Skip to content

Advertisement

  • Review
  • Open Access

Platelet integrin αIIbβ3: signal transduction, regulation, and its therapeutic targeting

Contributed equally
Journal of Hematology & Oncology201912:26

https://doi.org/10.1186/s13045-019-0709-6

  • Received: 23 December 2018
  • Accepted: 21 February 2019
  • Published:

Abstract

Integrins are a family of transmembrane glycoprotein signaling receptors that can transmit bioinformation bidirectionally across the plasma membrane. Integrin αIIbβ3 is expressed at a high level in platelets and their progenitors, where it plays a central role in platelet functions, hemostasis, and arterial thrombosis. Integrin αIIbβ3 also participates in cancer progression, such as tumor cell proliferation and metastasis. In resting platelets, integrin αIIbβ3 adopts an inactive conformation. Upon agonist stimulation, the transduction of inside-out signals leads integrin αIIbβ3 to switch from a low- to high-affinity state for fibrinogen and other ligands. Ligand binding causes integrin clustering and subsequently promotes outside-in signaling, which initiates and amplifies a range of cellular events to drive essential platelet functions such as spreading, aggregation, clot retraction, and thrombus consolidation. Regulation of the bidirectional signaling of integrin αIIbβ3 requires the involvement of numerous interacting proteins, which associate with the cytoplasmic tails of αIIbβ3 in particular. Integrin αIIbβ3 and its signaling pathways are considered promising targets for antithrombotic therapy. This review describes the bidirectional signal transduction of integrin αIIbβ3 in platelets, as well as the proteins responsible for its regulation and therapeutic agents that target integrin αIIbβ3 and its signaling pathways.

Keywords

  • Integrin αIIbβ3
  • Signal transduction
  • Talin
  • Kindlin
  • Transmembrane proteins
  • Therapeutic targeting

Background

Integrins, a family of transmembrane glycoprotein signaling receptors, comprise two distinct, noncovalently associated subunits, α and β. Each subunit consists of a large extracellular domain that contributes to ligand binding, a single-pass transmembrane (TM) domain, and a smaller unstructured cytoplasmic tail of approximately 20~70 amino acids (except β4). The cytoplasmic tail provides binding sites for adaptors, signaling proteins, and cytoskeleton-associated proteins, which play an essential role in integrin bidirectional signaling (inside-out signaling and outside-in signaling) [1]. In mammals, 18 α and 8 β subunits can combine in a restricted manner to form at least 24 integrins, which exhibit considerably different ligand binding properties, resulting in wide-ranging impacts on cellular functions, such as cell adhesion, spreading, migration, survival, differentiation, proliferation, and apoptosis [1]. Integrins can be grouped into 8 subgroups based on the identity of their β subunits (β1, β2, β3, β4, β5, β6, β7, and β8) [1]. Two subgroups of integrins are present in human platelets: β1 and β3, which account for a total of five human platelet integrins. Three β1 integrins are found in platelets, namely, α2β1, α5β1, and α6β1, which support platelet adhesion to the extracellular matrix proteins collagen [2], fibronectin [3], and laminin [4, 5], respectively. Two β3 integrins are present on platelets, namely, αvβ3 and αIIbβ3 [4, 5]. A variety of cells, including endothelial cells, smooth muscle cells, and fibroblasts, express αvβ3. However, there are only a few hundred copies of integrin αvβ3 per platelet [6, 7], and its function in platelets remains poorly understood. By contrast, αIIbβ3, also known as the glycoprotein GPIIb/IIIa (CD41/CD61) complex, is the dominant integrin on platelets and is essential for normal platelet functions. Integrin αIIbβ3 was also found to be expressed in tumor cells [8]. Integrin αIIbβ3 can bind to several arginine-glycine-aspartic acid (RGD)-containing ligands, including fibrinogen, fibrin, von Willebrand factor (vWF), and fibronectin. Of these ligands, fibrinogen is the major ligand. Integrin αIIbβ3 also interacts with the KQAGDV sequence of the fibrinogen γ-chain to cross-link platelets [9]. Glanzmann’s thrombasthenia (GT) is a rare autosomal recessive bleeding disorder that arises from disrupted αIIb and/or β3 subunit synthesis and function due to missense, nonsense, frame shift, or point mutations and exon skipping in the αIIb or β3 genes. This disruption impairs normal platelet functions, such as adhesion, spreading, and aggregation [1012]. However, nonphysiological αIIbβ3-mediated platelet activation and aggregation often cause pathological arterial thrombosis [13].

Quantitative studies using 7E3 mAbs eventually confirmed that each unstimulated platelet presents approximately 50,000–100,000 copies of αIIbβ3 on its surface [14], and additional αIIbβ3 molecules in the α-granule membranes are recruited to the platelet surface during platelet secretion, particularly by stimulatory agonists, such as thrombin or adenosine diphosphate (ADP) [15, 16]. A critical characteristic of αIIbβ3 is that it can transmit bidirectional signaling. In resting platelets, integrin αIIbβ3 adopts an inactive conformation. In this state, the extracellular domain has low affinity for its ligands. However, upon agonist stimulation, the cytoplasmic tails of integrin αIIbβ3 are bound by intracellular proteins, particularly talin and/or kindlin. Binding triggers an unclasping of the intracellular and transmembrane αIIbβ3 complex, leading to a conformational change in the extracellular domain. This conformational change leads αIIbβ3 to switch from low affinity (inactive) to high affinity (active) for its ligand (fibrinogen). This process is known as inside-out signaling or integrin αIIbβ3 activation. The outside-in signaling of αIIbβ3 on platelets is triggered by the binding of fibrinogen to activated integrin αIIbβ3, leading to a cascade of intracellular signaling events that mediate irreversible stable adhesion, spreading, clot retraction, irreversible aggregation, and cytoskeletal reorganization of platelets, as well as subsequent thrombus growth.

Bidirectional signaling of integrin αIIbβ3 is vital for platelet functions, hemostasis, and arterial thrombosis. Bidirectional signaling of integrin αIIbβ3 also plays an important role in cancer progression through regulating the interaction of integrin αIIbβ3 with the fibrinogen/αvβ3 complex on the surface of tumor cells [8] and/or releasing vascular endothelial growth factor (VEGF) from activated platelets [17]. An improved understanding of integrin αIIbβ3 signal transduction and regulation will result in greater progress in understanding thrombosis and developing therapeutic agents. Several excellent reviews have provided an overview of the structure of integrin αIIbβ3 and its bidirectional signaling [1823]. This brief review describes platelet integrin αIIbβ3 bidirectional signaling, the proteins responsible for regulating signal transduction, and the therapeutic agents targeting integrin αIIbβ3 and/or its signaling.

Integrin αIIbβ3 inside-out signaling

The inside-out signaling of αIIbβ3 on platelets can be initiated by various soluble agonists, such as epinephrine, ADP, thromboxane A2 (TXA2), or thrombin, which bind to G protein-coupled seven-transmembrane domain receptors (GPCRs). Inside-out signaling can also be initiated by immobilized agonists, such as vWF or collagen, which mainly interact with GPIb-IX-V or GPVI, respectively. Inside-out signaling includes (1) intracellular activators (such as talin or kindlin) binding to integrin αIIbβ3 tails, (2) separation of the α and β TM and the cytoplasmic tail, (3) a conformational change of the extracellular domain of αIIbβ3, and (4) increasing ligand binding affinity and avidity. To date, talin, kindlin, and other proteins have been identified as directly or indirectly interacting with integrin cytoplasmic tails to participate in the inside-out signaling of αIIbβ3 [24].

Talin

Talin has long been known to play an essential role in integrin activation. As an integrin-actin adaptor protein, it is an autoinhibited dimer with a head-to-tail conformation [25]. It consists of a globular N-terminal head (talin-H, approximately 50 kDa) and a large flexible C-terminal rod region (talin-R, approximately 200 kDa) (Fig. 1) [26]. There is a short linker sequence containing a calpain-II cleavage site between the talin-H and talin-R regions [27]. The talin-H region contains an F0 subdomain and a so-called 4.1, ezrin, radixin, moesin (FERM) domain, comprising three subdomains named F1, F2, and F3. The F3 subdomain has a phosphotyrosine-binding domain (PTB)-like fold [28], which binds with high affinity to the first (or membrane-proximal) of two conserved NPXY motifs in the β tails at integrin-binding site 1 (IBS1) [29]. The F3 subdomain can also interact with phosphatidylinositol 4-phosphate 5-kinase isoform 1γ (PIPK1γ) [30], layilin [31], and focal adhesion kinase (FAK) [32]. The talin-R region is composed of 13 amphipathic helical bundle domains (R1-R13, containing 62 α-helices), each consisting of four or five α-helices. The talin-R region contains at least two actin-binding sites [33], a second integrin-binding site (IBS2) [34], and multiple binding sites for vinculin [35]. Thus, talin-H binds to the evolutionarily conserved NPXY motif of the β cytoplasmic tails of integrins, connecting the integrin with the actin cytoskeleton through the actin-binding site of talin-R.
Fig. 1
Fig. 1

Domains and binding sites of talin. Talin-H comprises an atypical FERM domain containing F0, F1, F2, and F3 domains. Talin-R is composed of 13 amphipathic helical bundle domains (R1-R13, containing 62 α-helices), each consisting of four or five α-helices. A calpain-II cleavage site lies between talin-H and talin-R. Binding sites for interacting proteins are indicated by horizontal lines

Over the past 20 years, studies in cultured cells [36], mouse models [37, 38], and purified protein-reconstituted systems [39] have reinforced the notion that talin is an essential regulator of integrin ligand affinity. Binding of talin-H to the conserved N744PLY747 motif of the β3 tail is proposed to induce αIIbβ3 activation by disrupting the salt bridge between αIIb and the β3 tail [21]. Talin-H is sufficient to induce integrin activation, as evidenced by the fact that talin-H was able to induce integrin αIIbβ3 binding to the activation-specific mAb PAC-1 [40]. Studies on murine embryonic stem cell-derived megakaryocytes with talin knockdown have shown that talin is required for integrin αIIbβ3 activation in response to different agonists [41]. Furthermore, mice expressing the L746A mutation of β3 integrin, which is believed to selectively disrupt the interaction between αIIbβ3 and talin, display impaired inside-out activation of αIIbβ3 [42]. Conditional deletion of talin-1 in mice showed that integrin αIIbβ3 is unable to activate in response to any tested agonists [43, 44]. This finding suggests that talin plays a crucial role in homeostasis and that talin is required for the activation and function of αIIbβ3 in vivo [43, 44]. Thus, disruption of the interaction of talin with integrin β3 may offer a strategy for anti-thrombosis [42, 45]. Recent data utilizing phospholipid nanodiscs bearing a single lipid-embedded integrin have also shown that talin-H binding to the integrin β3 tail is sufficient for integrin activation in the absence of other proteins [39]. However, solid evidence has clearly demonstrated that integrin activation also requires the cooperation of kindlin alongside talin [4651].

Kindlin

A series of publications have established a requirement for kindlin coordinating with talin for integrin αIIbβ3 inside-out signaling [47, 48, 52, 53]. In mammals, there are three evolutionarily conserved members of the kindlin family: kindlin-1, kindlin-2, and kindlin-3 [54, 55]. Kindlin-1 is ubiquitously expressed in epithelial cells, and kindlin-2 is broadly expressed in all solid tissues of mesenchymal origin. In contrast, kindlin-3 is mainly restricted to hematopoietic cells [56, 57]. However, recent experimental work has shown that kindlin-3 is also expressed in endothelial cells [58]. Mutations in the kindlin-1 gene lead to Kindler syndrome, which is characterized by serious skin blistering, progressive poikiloderma, photosensitivity, and atrophy of the skin [59, 60]. Mutations in the kindlin-3 gene lead to type-III leukocyte adhesion deficiency (LAD-III), as well as recurrent infections, immune deficiencies, and severe bleeding disorders caused by the dysfunction of integrins in leukocytes and platelets; loss of hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) in the bone marrow; elevated leukocyte counts; and osteopetrosis [6164]. To date, no human diseases have been associated with mutations of the kindlin-2 gene, but kindlin-2 is highly expressed in cancers of the lung, prostate, pancreas, liver, and esophagus [65]. Knockout of kindlin-2 is embryonically lethal in mice and causes multiple severe abnormalities in zebrafish due to impaired integrin activation [49, 66, 67].

Using Chinese hamster ovary (CHO) cells expressing integrin αIIbβ3, the Calderwood group reported that kindlin-1 and talin cooperatively enhance integrin αIIbβ3 activation [52, 68] and that kindlin-2 is also a coactivator of talin-H in regulating integrin αIIbβ3 activation [48, 49]. Using kindlin-3−/− mice, Moser et al. showed that in platelets lacking kindlin-3, integrin αIIbβ3 could not be activated despite normal talin expression [47]. Kindlin itself is incapable of unclasping the intracellular and transmembrane αIIbβ3 complex [69], and consequently, it is insufficient to trigger effective inside-out signaling of integrin αIIbβ3 [48]. However, there is a lack of evidence for the direct interaction between kindlins and talin-H [69]. Further studies will be required to address the unanswered question of how kindlin cooperates with talin to induce integrin activation. The tyrosine phosphorylation of the membrane-proximal N744PLY747 motif of the integrin β3 tail negatively regulates talin binding [70, 71]. Similar to talin, tyrosine phosphorylation of the membrane-distal N756ITY759 motif also inhibits kindlin-2 binding [46]. These observations suggest that transitions between the phosphorylated and nonphosphorylated states of the integrin β3 tail affect talin/kindlin-regulated integrin activation [46]. Tyrosine phosphorylation of the β3 tail also regulates β3 cleavage by calpain [72]. Structures of the kindlin-2/β-tail complex showed that the dimeric forms of kindlin-2 can bridge talin-activated integrins and promote integrin clustering [73]. Recent studies revealed that integrin-linked kinase (ILK) can interact with the F2 subdomain of kindlin-2 with high affinity and support αIIbβ3 activation [74, 75]. ADAP, a hematopoietic-specific adapter protein, is physically proximal to talin and kindlin-3 in human platelets. ADAP, when acting as a bridging molecule between kindlin and talin, promotes platelet integrin αIIbβ3 activation [38, 76, 77]. The paxillin (PXN) family members (paxillin and Hic-5) act as bridging molecules and are also able to promote platelet integrin αIIbβ3 activation by cooperating with kindlin and talin [51, 78, 79]. However, the exact details of how ILK, ADAP, paxillin, and Hic-5 assist kindlin and talin in mediating αIIbβ3 activation remain largely unknown.

Other proteins that positively regulate integrin αIIbβ3 activation

In addition to talin and kindlin, other proteins, such as ILK [80], β3-endonexin [81, 82], calcium- and integrin-binding protein 1 (CIB1) [83, 84], chloride channel regulatory protein (ICln) [85], catalytic subunit of protein phosphatase 1 γ (PP1cγ) [86], and vinculin [87], may be involved in integrin αIIbβ3 activation. However, little is known about how these proteins exert effects on integrin activation and signaling. In addition to interacting with kindlin, ILK serves as an adaptor protein that forms the ILK/PINCH/parvin (IPP) complex with PINCH and parvins. The IPP complex interacts directly with the β3 cytoplasmic tail via ILK and regulates integrin activation in platelets. Loss of ILK has been reported to inhibit integrin activation, as assessed by the binding of soluble fibrinogen and PAC-1 [75, 80, 88, 89]. Platelets stimulated by ADP or phorbol 12-myristate 13-acetate (PMA) exhibited an increase in ILK activity associated with phosphorylation of β3 [90]. ILK−/−mice showed increased bleeding time, reduced aggregation, soluble fibrinogen binding, and defects in α-granule secretion [88]. These observations suggested that ILK may be involved in integrin αIIbβ3 inside-out and outside-in signaling. β3-Endonexin is a molecule that is known to induce αIIbβ3 activation in CHO cells by interacting with the N756ITY759 motif of the integrin β3 cytoplasmic tail. β3-Endonexin is present in resting human platelets. Nonetheless, there is little available information about how β3-endonexin regulates integrin αIIbβ3 [91, 92]. CIB1 can disrupt the association of αIIb and β3 by binding to the αIIb cytoplasmic tail, which in turn activates integrin αIIbβ3 [83, 93]. However, CIB1 has also been reported to negatively regulate the activation of integrin αIIbβ3 by competing with talin for binding to αIIbβ3 [84]. ICln binds to the membrane-proximal KVGFFKR motif of integrin αIIb regardless of the integrin activation state, and ICln regulates platelet activation through an integrin activation-dependent subcellular redistribution mechanism [85]. Using the γ isoform of PP1c-deficient (PP1cγ−/−) mice, Gushiken et al. showed that PP1cγ mainly participates in thrombin-induced integrin αIIbβ3 inside-out signaling but not ADP or collagen-related integrin αIIbβ3 inside-out signaling. Vinculin, a marker for integrin-mediated focal adhesion complexes, inhibits Rap1-GTP-interacting adaptor molecule (RIAM) binding to talin and plays a role in inside-out signaling of αIIbβ3 [87, 94]. Using CHO cells expressing αIIbβ3, Ohmori et al. reported that vinculin induces αIIbβ3 inside-out signaling through talin-1, while it is dispensable for outside-in signaling [87]. However, conditional deletion of the vinculin gene (Vcl) showed that tail bleeding times in Vcl−/− mice were prolonged, but platelet functions, including agonist-induced fibrinogen binding to αIIbβ3, spreading, clot retraction, platelet aggregation, and adhesion on immobilized fibrinogen or collagen, were similar to those of wild-type mice [95].

Proteins that negatively regulate integrin αIIbβ3 activation

Several proteins are thought to bind directly to one of the integrin αIIb or β3 cytoplasmic tails to inhibit integrin αIIbβ3 activation. CIB1 plays a role in the possible negative regulation of integrin αIIbβ3 activation by binding directly to the GFFKR sequence of the αIIb cytoplasmic tail [84, 96], whereas docking protein 1 (Dok1) [71], filamin [97], and tensin 1 [98] impair integrin activation by binding directly to the β3 cytoplasmic tail [99]. There are conflicting reports on the function of CIB1 proteins in αIIbβ3 activation. Tsuboi et al. first reported that CIB1 plays an important role in the activation of αIIbβ3 in platelets [83]. When platelets were incubated with a palmitoylated peptide corresponding to the C-terminus of CIB1 (residues 179–188), no significant PAC-1 binding to αIIbβ3 was detected in the presence of physiological agonists such as ADP and thrombin. Contrasting results were reported for the overexpression of CIB1 in megakaryocytes, which completely prevented agonist-induced integrin αIIbβ3 activation, whereas overexpression of a CIB1 F173A mutant resulted in failure to interact with the αIIb cytoplasmic tail and was unable to suppress agonist-induced integrin αIIbβ3 activation. Conversely, the reduction of endogenous CIB1 via RNA interference enhanced agonist-induced integrin αIIbβ3 activation [84]. However, Denofrio et al. reported that there was no significant difference in integrin αIIbβ3 expression, agonist-induced αIIbβ3 binding to JON/A, P-selectin expression, platelet aggregation, platelet spreading, bleeding time, or FeCl3-induced thrombus formation between Cib1+/+ and Cib1−/−mice, possibly owing to compensation by CIB2 and CIB3 [100]. In contrast to the report of Denofrio et al., Cib1−/−mice showed a rebleeding phenotype and defective thrombosis due to impaired integrin αIIbβ3 outside-in signaling [101]. Dok1 is a PTB domain-containing protein. Expression of Dok1 in CHO cells expressing chimeric αIIbα6Aβ3β1A inhibited integrin activation by competing with talin for the PTB binding sites in the β1A cytoplasmic tail [102]. The integrin β3 cytoplasmic tail also has the ability to bind Dok1 [103] and impair αIIbβ3 activation. Recent studies revealed that the 14-3-3ξ/Dok1 binary complex binds to the phosphorylated cytoplasmic tail of integrin β3 and regulates integrin activation [104]. Some studies reported that knockout of Dok1 or Dok2 did not affect platelet integrin αIIbβ3 inside-out signaling, as evidenced by normal aggregation, JON/A binding, and soluble fibrinogen [105, 106]. Crystal structure studies have shown that filamin and tensin 1 can compete with talin for binding to the integrin β3 tail [107]. The roles of filamin and tensin 1 in αIIbβ3 inside-out signaling need to be further investigated using CHO cells or platelets. A gain-of-function mutation in filamin A (stop codon mutation p. Ter2648SerextTer101) potentiates platelet integrin αIIbβ3 activation by facilitating recruitment of talin to the β3 tail [108]. Recent studies have demonstrated that α-actinin plays a role in maintaining αIIbβ3 in an inactivated state [109]. Due to partial overlapping of α-actinin binding sites with talin binding sites in the β3 cytoplasmic tail, α-actinin association with αIIbβ3 may block the access of talin to the β3 tails [109, 110]. α-Actinin induces a kink in the transmembrane domain of integrin β3 [109111], which maintains integrin αIIbβ3 in a low-affinity state [111].

Agonist-induced integrin αIIbβ3 activation

Knowledge of how agonists lead to integrin αIIbβ3 activation by talin and/or kindlin is vital for understanding inside-out signaling of αIIbβ3 (Fig. 2). The initial adhesion of platelets at the site of damaged vessel walls is mainly facilitated by GPIb-IX-V/collagen-bound vWF and/or GPVI-collagen interactions. These two interactions trigger integrin αIIbβ3 inside-out signaling and play a primary role in platelet activation. The GPIb-IX-V complex contains four type I transmembrane glycoproteins: GPIbα, GPIbβ, GPIX, and GPV. After vascular injury, circulating vWF in the plasma binds to the exposed collagen within the subendothelium through its A3 domain. The interaction of collagen and vWF-A3 enables vWF to expose the A1 domain, which is essential for collagen-bound vWF to interact with the GPIb subunit. In addition, factor XII, P-selectin, and leukocyte integrin MAC-1 are all able to bind to GPIb-IX-V and modulate integrin αIIbβ3 activation [112]. The interaction of vWF with GPIb-IX-V induces activation of the Src family kinases (Src, Lyn, and Fyn) and phosphorylation of its downstream substrates, including the Fc receptor γ-chain (FcRγ) and FcRγIIa [113116]. PLCγ tyrosine phosphorylation is mediated by the immunoreceptor tyrosine-based activation motif (ITAM)-bearing receptors FcRγ and FcRγIIa. PLCγ is also activated by GPVI-collagen interactions through FcRγ signaling involving tyrosine kinases, such as Src and spleen tyrosine kinase (Syk) [117]. In addition to PLCγ, phosphatidylinositol-3-kinase (PI3K) is another key molecule downstream of GPVI and GPIb-IX-V [118]. Collagen- or vWF-induced signaling leads to the release of ADP, TXA2, 5-hydroxytryptamine (5-TH), and thrombin, which triggers PLCβ activation via GPCRs, such as the P2Y1, TP, 5-TH2A, and PAR receptors. PLCβ is downstream of GPCRs, whereas PLCγ is activated by VWF/GPIb-IX-V or collagen/GPVI interactions [118, 119]. PI3K signaling leads to Rap1 activation, which is a Ca2+-independent process [120]. Unlike PI3K, PLC activation hydrolyzes platelet membrane phosphatidylinositol (4,5)-bisphosphate (PI-4,5-P) into the second messengers diacylglycerol (DAG) and inositol (1,4,5)-triphosphate (IP3). In turn, IP3 releases calcium from intracellular stores through IP3 receptor (IP3-R) channels [121], increasing the Ca2+ concentration in the platelet cytosol. DAG and Ca2+ activate many isoforms of platelet protein kinase C (PKC) and Ca2+ diacylglycerol guanine-nucleotide-exchange factor I (CalDAG-GEFI, a guanine exchange factor for Rap1), leading to the conversion of Rap1-GDP to Rap1-GTP and the translocation of Rap1-GTP to the plasma membrane [122124]. In CalDAG-GEFI−/− mice, induction of inside-out activation of integrin αIIbβ3 by calcium ionophore, collagen, ADP, and a TXA2 analog was strongly inhibited. In contrast, thrombin-induced activation of αIIbβ3 was mildly affected [125]. This finding suggests that other molecules may transform the signal from the agonist to the αIIbβ3 cytoplasmic tails and cause αIIbβ3 activation. In addition to CalDAG-GEFI, the activation of PKC also leads to the shift of Rap1-GDP to Rap1-GTP in platelets. There are at least four PKC isoforms (α, β, δ, and θ) [126] in human platelets. Using CHO cell models, Han et al. reported that Rap1-GTP was downstream of PKCα in integrin αIIbβ3 activation [127]. Platelets from PKCα−/− mice showed that PKCα was a regulator of inside-out signaling of αIIbβ3 [128] but did not play a significant role in the outside-in signaling of αIIbβ3. Rap1b−/− mice demonstrated that ADP- or AYPGKF-induced integrin αIIbβ3 activation was impaired, as was FeCl3-dependent arterial thrombosis [129]. Interestingly, overexpression of Rap1a in CHO cells leads to αIIbβ3 activation [127], but it does not appear to be required for integrin αIIbβ3 activation in platelets [129].
Fig. 2
Fig. 2

Schematic of integrin αIIbβ3 inside-out signaling in platelets. Soluble agonist (ADP, epinephrine, 5-HT, TXA2, and thrombin) stimulation of G protein-coupled receptors (GPCRs) triggers PLCβ activation. Collagen-bound vWF/GPIb-IX-V and collagen/GPVI interactions ultimately induce PLCγ activation. PLC hydrolyzes platelet membrane phosphatidylinositol (4,5)-bisphosphate (PI-4,5-P, PIP2) into diacylglycerol (DAG) and inositol (1,4,5)-triphosphate (IP3). IP3 induces Ca2+ release. DAG, together with Ca2+, activates CalDAG-GEFI and PKC. Activated CalDAG-GEFI along with PKC leads to the shift of Rap1-GDP to Rap1-GTP. Rap1-GTP targets the lipid membrane through farnesylation of its CAAX motif. RIAM functions as a linker between Rap1-GTP and talin, forming a Rap1/RIAM/talin complex. Complex-bound talin interacts with the integrin β3 subunit through the plasma membrane. Binding of talin-H (FERM domain) to the NPLY motif of the β3 tail disrupts the salt bridge between the αIIb and β3 subunits, leading to integrin αIIbβ3 activation, shifting from a bent to an extended conformation. Kindlin binding to the NITY motif of the β3 tail is shown. CIB1 directly binds to the αIIb cytoplasmic tail. ADAP serves as a bridging molecule between kindlin and talin, promoting platelet integrin αIIbβ3 activation

Rap1 mediates inside-out activation of integrin αIIbβ3 through another effector, called Rap1-GTP-interacting adaptor molecule (RIAM), on the membrane. RIAM is a member of the Mig-10/RIAM/lamellipodin (MRL) family of adaptor molecules. RIAM recruits talin-1 to integrin αIIbβ3. Knockout of RIAM in megakaryocytes abolishes Rap1-dependent αIIbβ3 activation [130]; however, deletion of RIAM in mice does not affect αIIbβ3 activation [131]. Rap1 activation induces the formation of an “integrin activation complex” containing Rap1, RIAM, and talin, leading to αIIbβ3 activation [127, 130]. Bimolecular fluorescence complementation (BiFC) has revealed that in CHO cells, knockdown of RIAM blocks talin recruitment to αIIbβ3, whereas overexpression of Rap1a or RIAM enhances talin recruitment to αIIbβ3 [132]. RIAM acts as a scaffold that connects the membrane targeting sequences in Rap1-GTP to talin, thereby recruiting talin to the plasma membrane and activating integrins [130]. Whether kindlin is a member of the “integrin activation complex” still warrants further investigation. In addition to the Rap1/RIAM/talin complex pathway, membrane-anchored Rap1b interacts with the F0 domain of talin, triggering integrin αIIbβ3 activation in a RIAM-independent fashion [133]; however, a recent study reported conflicting results [134]. The interaction of the F0 domain of talin with Rap1b plays no evident role in talin-H-induced αIIbβ3 activation [134]. Schiemer et al. recently reported that switch region 2 of G13α had the ability to mediate talin activation from its autoinhibition station and further regulate integrin αIIbβ3 activation [135].

Integrin αIIbβ3 outside-in signaling

The outside-in signaling of integrin αIIbβ3 on platelets is triggered by the binding of soluble fibrinogen to activated integrin αIIbβ3 (Fig. 3), leading to the generation of a cascade of intracellular signaling events that mediate irreversible stable adhesion, spreading, cytoskeletal reorganization and irreversible aggregation of platelets, and subsequent thrombus growth. Similar to the inside-out signaling of αIIbβ3, outside-in signaling of αIIbβ3 requires cooperating proteins to directly or indirectly interact with the αIIbβ3 cytoplasmic tails because the cytoplasmic tails themselves lack any intrinsic enzymatic activity (Fig. 4). Many of the recent advances in our understanding of the proteins that regulate outside-in signaling of αIIbβ3 have come from mouse gene knockout studies (Table 1). To date, the identified proteins that participate in outside-in signaling of αIIbβ3 are more numerous than those involved in inside-out signaling of αIIbβ3. However, there are some proteins associated with both inside-out and outside-in signaling, such as talin and kindlin-3. The proteins that regulate outside-in signaling of αIIbβ3 can be classified into four major categories: transmembrane proteins, intracellular adaptor molecules, kinases and phosphatases, and Rho-family small GTPases.
Fig. 3
Fig. 3

Schematic of integrin αIIbβ3 outside-in signaling in platelets. Following ligand binding to the extracellular domain of integrin αIIbβ3, integrin αIIbβ3 clustering promotes Src activation by autophosphorylation. Calpain cleaves the integrin β3 cytoplasmic tail and leads to disassociation of partly active Src from the integrin β3 tail. Src phosphorylates and supports the activation of a wide range of enzymes and signaling proteins, such as FAK, Syk kinase, RhoGAP, Rac-GEFs, RhoGEFs, and PI3K. Gα13, talin, kindlin, tensin, and vinculin provide the necessary links between the integrin β3 cytoplasmic tail and actin. Kindlin can directly couple integrin β3 to the actin cytoskeleton via the ILK/PINCH/parvin complex

Fig. 4
Fig. 4

Amino acid sequence of the C-terminal tail of integrin β3, highlighting interaction sites involved in integrin αIIbβ3 bidirectional signaling. Calpain cleavage sites are indicated by arrows. Phosphorylatable amino acid residues (tyrosine and threonine) are labeled in red. Positions of the horizontal lines indicate sites on the integrin β3 cytoplasmic tail that interact with cytoplasmic signaling proteins

Table 1

Key regulatory proteins involved in integrin αIIbβ3 bidirectional signaling

Proteins

Integrin αIIbβ3 activation

Phenotype of knockout mice

Reference

ADAP

Significantly reduced soluble fibrinogen binding

Formation of unstable thrombi, increased tail rebleeding, reduced stable attachment, and impaired cytoskeletal reorganization under shear flow

[76, 77]

CalDAG-GEFI

Impaired JON/A antibody binding

Reduced aggregation, granule secretion, and adhesive function. Mild defect in hemostasis. Impaired Rap1 activation

[104, 123125]

c-Cbl

Null

Significantly reduced spreading on immobilized fibrinogen. Drastically impaired clot retraction

[220]

CD9

Increased soluble fibrinogen binding

Normal aggregation and α-granule release, normal hemostasis

[159]

CD63

Normal JON/A antibody binding

Normal α-granule release. Normal adhesion and thrombus formation on collagen under flow conditions

[249]

CD82

Normal JON/A antibody binding

Normal aggregation and granule secretion. Enhanced clot retraction, enhanced adhesion on fibrinogen. Reduced bleeding time and volume. Increased tyrosine phosphorylation in integrin αIIbβ3 signaling

[153]

CD84

Normal JON/A antibody binding

Normal granule secretion. Unaltered hemostatic function and arterial thrombus formation. Unaltered aggregate formation under flow. Unaltered function of CD84−/− platelets in vitro

[167]

CD148

Markedly reduced JON/A antibody binding

Exhibited a bleeding tendency and defective arterial thrombosis. Markedly reduced SFK activity. Impaired spreading on fibrinogen and collagen-induced aggregate formation under flow conditions. Delayed thrombus formation

[250]

CD151

Normal soluble fibrinogen and JON/A antibody binding

Normal α-granule, dense granule secretion, and platelet adhesion. Impaired platelet aggregation and platelet spreading on fibrinogen, delayed kinetics of clot retraction, restricted cytoskeletal reorganization. Increased bleeding time and volume and rebleeding, but without spontaneous bleeding complications

[150, 156, 157]

CEACAM-1

Null

Enhanced aggregation, enhanced platelet adhesion on type I collagen but not fibrinogen, elevated granule secretion, larger and more stable thrombi

[137]

CIB1

Normal soluble fibrinogen binding

Normal aggregation and α-granule secretion, increased tail bleeding time and rebleeding, formation of unstable thrombi, impaired spreading on immobilized fibrinogen, reduced tyrosine phosphorylation of the integrin β3 tail

[93, 101]

cPLA2α

Impaired fibrinogen binding in response to CRP or the lower concentration of PAR4 peptide

Impaired collagen-induced aggregation, spreading on fibrinogen, platelet aggregation. Prolonged bleeding time

[224, 225]

Dab2

Impaired soluble fibrinogen binding

Selectively defective in thrombin-induced aggregation, platelet spreading on fibrinogen and clot retraction. Impaired ADP release. Prolonged bleeding time and impaired hemostasis and thrombosis

[179]

Dok1

Normal soluble fibrinogen and JON/A antibody binding

Normal aggregation, P-selectin surface expression. Increased clot retraction, increased PLCγ2 phosphorylation, and enhanced spreading on fibrinogen. Significantly shortened bleeding time and accelerated carotid artery thrombosis

[105]

Dok2

Normal soluble fibrinogen and JON/A antibody binding

Enhanced shear-dependent integrin adhesion in platelets. Increased platelet thrombus formation

[106]

ERp57

Impaired JON/A antibody binding

Prolonged tail bleeding time and thrombus occlusion time. Impaired platelet aggregation

[251]

ESAM

Normal JON/A antibody binding

Normal calcium mobilization, α-granule secretion and platelet spreading, more stable hemostasis. Formation of larger thrombi, increased aggregation, and more resistant to disaggregation

[145]

G6b-B

Reduced soluble fibrinogen binding

Megakaryocytes exhibited a marked reduction in spreading on fibrinogen or fibronectin, increased bleeding, failure to form normal aggregates on collagen-coated surfaces under flow condition. Impaired secretion of ATP, but not P-selectin, and reduced spreading

[140, 141]

Gα13

Normal soluble fibrinogen binding

Mutation of the Gα13-binding β3 ExE motif. Impaired stable thrombus formation. Increased tail bleeding time

[168, 169, 181]

Gas6, Gas6 receptors

Normal soluble fibrinogen binding, impaired PAC-1 binding

Failure to spread to fibrinogen, impaired dense granule secretion. No spontaneous bleeding, normal bleeding time but a tendency to repetitively rebleed. Lacked the second wave of platelet aggregation, with impaired clot retraction, reduced thrombus formation, and increased disaggregation. Reduced tyrosine phosphorylation of the integrin β3 tail

[160, 161, 163]

ILK

Reduced rate of soluble fibrinogen binding

Reduced α-granule secretion. Impaired aggregation, increased thrombus instability and tail bleeding time and volume

[88, 89]

JAM-A

Normal soluble fibrinogen and JON/A antibody binding

Normal α-granule secretion, enhanced thrombus formation, augmented platelet spreading and aggregation, enhanced clot retraction, shorted tail bleeding time

[147, 148]

Kindlin-3

Failed to bind soluble fibrinogen and JON/A antibody

Kindlin-3 deficiency results in severe bleeding and resistance to arterial thrombosis

[47]

Lnk

Normal soluble fibrinogen binding

Normal P-selectin expression. Reduced spreading on fibrinogen, impaired clot retraction, reduced tyrosine phosphorylation of integrin β3 tail. Impaired thrombus stability. Lnk promotes integrin αIIbβ3-mediated actin cytoskeleton reorganization

[176]

MEKK3

Impaired soluble fibrinogen binding

Reduced aggregation and granule secretion. Delayed thrombus formation and fewer microthrombi, normal tail bleeding time

[252]

Myosin

Normal soluble fibrinogen and JON/A antibody binding

Normal platelet aggregation and secretion. Increased bleeding time and absence of clot retraction. Reduced tyrosine phosphorylation of integrin β3 tail. Impaired thrombus growth, organization, and thrombus stability. Increased tail bleeding time

[172]

NLRP3

Normal JON/A antibody binding

Prolonged tail bleeding time, delayed arterial thrombus formation, impaired spreading on immobilized fibrinogen, defective clot retraction, mildly reduced platelet aggregation, normal P-selectin expression, decreased phosphorylation of Src, Syk, and PLCγ2 in response to thrombin stimulation

[13]

Palladin+/−

Null

Accelerated hemostasis and arterial thrombosis. Increased aggregation, spreading on immobilized fibrinogen, and rate of clot retraction

[253]

Paxillin

Enhanced JON/A antibody binding

Enhanced platelet aggregation and granule secretion, increased spreading on fibrinogen and clot retraction, increased tyrosine phosphorylation and calcium mobilization, increased thrombus formation

[79]

PDK1

Normal soluble fibrinogen binding

Diminished aggregation and spreading on immobilized fibrinogen and decreased rate of clot retraction

[254]

PECAM-1

Normal soluble fibrinogen and JON/A antibody binding

Normal α-granule secretion and aggregation, impaired spreading on immobilized fibrinogen and clot retraction, reduced tyrosine phosphorylation of FAK

[136]

PI3Kα

Null

Impaired platelet aggregation at low concentrations of CRP. Modest but significant decrease in thrombus size after superficial injury of mouse mesenteric arteries. Increased time to arterial occlusion after carotid lesion, without modification of the tail bleeding time

[219]

PKCα

Impaired soluble fibrinogen binding

Normal spreading on fibrinogen and collagen. Impaired granule release and aggregation. Markedly attenuated thrombus formation. Normal tail bleeding time

[128]

PKCβ

Normal soluble fibrinogen binding

Spread poorly on fibrinogen

[209]

PKCθ

Increased JON/A antibody binding

Partially impaired spreading on fibrinogen, but not on CRP or collagen. Increased CRP-induced granule release, unaltered platelet aggregation, and formation of significantly larger thrombi

[212, 213]

PKCι/λ

Normal JON/A antibody binding

Unaltered platelet spreading and function in vitro and in vivo under all tested conditions. Unaltered in vivo thrombus formation in PKCι/λ−/− mice

[206]

PP1cγ

Moderately decreased soluble fibrinogen binding with low concentrations of thrombin or PAR4, but not ADP, collagen or CRP

Mild agonist-specific decreased aggregation. Normal granule secretion, adhesion to immobilized fibrinogen, and clot retraction. Significantly delayed thrombus formation

[86]

PTEN

Null

Shortened tail bleeding time, increased sensitivity of platelets to collagen-induced activation and aggregation

[255]

PTP-1B

Normal soluble fibrinogen binding

Poor spreading on fibrinogen and decreased clot retraction, markedly reduced thrombus formation. Prolonged tail bleeding time, but without spontaneous bleeding

[199]

Pyk2

Impaired soluble fibrinogen binding

Defective spreading on fibrinogen. Impaired aggregation and thrombus formation. Slightly prolonged tail bleeding

[221, 222]

Rac1

Null

Defective spreading on fibrinogen. Reduced thrombus formation and stability. Prolonged tail bleeding

[228, 256]

Rap1b

Impaired soluble fibrinogen binding

Impaired spreading on fibrinogen. Increased tail bleeding time. Reduced platelet aggregation. Rap1b−/−mice are protected from thrombosis in an in vivo thrombosis model

[129]

Reelin

Reduced soluble fibrinogen binding

Impaired platelet adhesion. Significantly reduced thrombus formation under high shear conditions and protected from arterial thrombosis. Normal hemostasis

[192]

RhoA

Normal JON/A antibody binding

Impaired α-granule release. Markedly prolonged tail bleeding time but also significant protection in different models of arterial thrombosis and in a model of ischemic stroke. Normal spreading on fibrinogen, impaired clot retraction, moderately reduced aggregate formation

[227]

RIAM

Normal soluble fibrinogen and JON/A antibody binding

Normal adhesion and aggregation responses under static and flow conditions. Unaltered hemostasis and arterial thrombus formation

[131]

ROCK2

Slightly impaired fibrinogen binding

Impaired adhesion and spreading on collagen, reduced aggregation. Prolonged bleeding time and delayed vascular occlusion following vessel injury

[257]

Semaphorin 4D

Normal soluble fibrinogen binding

A selective defect in collagen-induced platelet aggregation and an impaired vascular injury response. Spleen tyrosine kinase activation, and subsequent downstream events are greatly reduced in Sema 4D−/− platelets. Normal spreading on collagen under flow conditions

[165]

SFKs

Normal JON/A antibody binding

Mouse platelets deficient in c-Src display impaired spreading on fibrinogen. Some redundancy with other SFKs such as Fyn and Lyn occurs, whereas Lyn is important for thrombus formation. However, Lyn also plays a negative regulatory role in cell spreading. Fyn−/− platelets display delayed spreading on fibrinogen and prolonged rebleeding time. Loss of SFKs does not affect tail bleeding

[114116, 176, 200, 214]

SHIP1

Null

SHIP1 plays a major role in regulating integrin αIIbβ3-dependent PI(3,4,5)P3 accumulation. Enhanced platelet spreading

[214]

SLP-76

Normal soluble fibrinogen binding

Impaired spreading on fibrinogen, collagen-induced platelet aggregation, and granule release. Fetal hemorrhage. Reduced tyrosine phosphorylation

[171, 182, 183]

Talin

Significantly reduced soluble fibrinogen binding

Impaired integrin αIIbβ3-mediated platelet aggregation and adhesion to collagen. Spontaneous hemorrhage and pathological bleeding

[41, 124]

TSSC6

Normal soluble fibrinogen and JON/A antibody binding

Normal platelet adhesion on fibrinogen and α-granule secretion. Increased bleeding time and volume and rebleeding. Unstable hemostasis. Impaired clot retraction, platelet aggregation, and spreading on fibrinogen

[151]

Vav1/3

Null

Impaired spreading on fibrinogen, reduced αIIbβ3-mediated PLCγ2 tyrosine phosphorylation, and reduced Ca2+ mobilization

[202]

Vinculin

Normal agonist-induced fibrinogen binding

Normal aggregation, adherence/spreading on immobilized fibrinogen or collagen, actin polymerization/organization, clot retraction. Prolonged tail bleeding time, but no spontaneous bleeding

[95]

VPS33B

Normal thrombin-induced soluble fibrinogen and JON/A antibody binding

Impaired spreading on fibrinogen, failure to support clot retraction. Reduced platelet aggregation and ATP secretion. Prolonged tail bleeding time

[170]

WASP

Normal fibrinogen, JON/A antibody and PAC-1 binding

Impaired adherence/spreading on immobilized fibrinogen, clot retraction and postaggregation. Primary hemostasis is normal, but rebleeding is increased

[180]

Transmembrane proteins

Immunoglobulin superfamily

Platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) is a membrane-spanning immunoglobulin protein that regulates outside-in signaling, but not inside-out signaling, of integrin αIIbβ3 [136, 137]. PECAM-1 recruits SHP-1 and SHP-2 to form a signaling complex, leading to Src and FAK activation. However, exactly how Src and FAK are activated following SHP-1 and SHP-2 recruitment to PECAM-1 are unknown. PECAM-1 can also trigger the internalization of GPIb [138]. Recently, G6B and carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM-1), which bears some similarities to PECAM-1 in its cytoplasmic tail, which contains ITIM domains, and its capacity to recruit SHP-1 and SHP-2, have been shown to negatively regulate platelet thrombus formation in vitro and in vivo [137, 139142]. Interestingly, platelets also express junctional adhesion molecule-A (JAM-A) [143] and endothelial cell-specific adhesion molecule (ESAM) [144, 145], which belongs to the cortical thymocyte marker of Xenopus (CTX) family of the immunoglobulin superfamily. JAM-A likely indirectly associates with integrin αIIbβ3 through CD9 [146]. In mouse knockout models, JAM-A was reported to negatively regulate αIIbβ3 outside-in signaling-mediated platelet thrombus formation through binding to Syk and inhibiting the activation of αIIbβ3-associated Src [147, 148].

Tetraspanin superfamily

The tetraspanins possess four conserved hydrophobic transmembrane regions: two extracellular loops and two intracellular tails (N-terminal and C-terminal). At least five members of the tetraspanin superfamily, CD151, tumor suppressing subtransferable candidate 6 (TSSC6), CD63, CD9, and CD82, have been reported to be expressed in platelets [149153]. However, there is little information on how these tetraspanins influence αIIbβ3 outside-in signaling. So far, immunoprecipitation and Western blot studies have revealed the physical association of CD151, CD63, TSSC6, and CD9 with αIIbβ3 in platelets [150, 151, 154, 155].

Studies using murine CD151−/− platelets have demonstrated that deletion of CD151 is capable of inhibiting the outside-in signaling properties of αIIbβ3, including reducing agonist-induced platelet aggregation, delaying clot retraction, diminishing platelet spreading on fibrinogen, and reducing formation of filopodia. However, CD151−/− platelets display normal αIIbβ3 inside-out signaling properties, as evidenced by standard agonist-induced binding of soluble fibrinogen or JON/A antibody [150, 156, 157]. Recent studies by Orlowski et al. that used three different models for thrombus formation have confirmed that platelet CD151 is required for regulating thrombus formation in vivo [149]. CD151 forms a CD151/P2Y12 receptor complex and participates in integrin αIIbβ3 outside-in signaling [157]. TSSC6 regulates integrin αIIbβ3 outside-in signaling by physically associating with the P2Y12 receptor [158]. Early studies suggested that CD63 might inhibit integrin αIIbβ3 outside-in signaling in platelets. D545, a CD63 monoclonal antibody, modulates αIIbβ3-mediated actin cytoskeleton reorganization, inhibiting platelet spreading on immobilized fibrinogen and impairing tyrosine phosphorylation of FAK. Tyrosine phosphorylation of FAK is a downstream marker of integrin αIIbβ3 outside-in signaling. Unlike the CD151 and TSSC6 tetraspanins, CD9 does not appear to play an important role in integrin αIIbβ3 outside-in signaling but does negatively regulate integrin inside-out signaling [159]. Future studies are required to explore the role of the tetraspanins in αIIbβ3 signaling.

Other transmembrane proteins

Growth arrest-specific protein 6 (Gas6) is a member of the vitamin K-dependent protein family. Recent studies of Gas6−/− mice have shown that Gas6 plays a role in platelet function [160162]. Gas6−/− mice have a normal bleeding time but a tendency to repetitively rebleed due to impaired αIIbβ3 outside-in signaling [160]. Interestingly, mice that have lost any one gene for the TAM family receptors (Tyro3, Axl, or Mer) display a phenotype similar to that of Gas6−/− mice [163]. Once Gas6 is secreted, it binds to the TAM family receptor on the platelet surface through the C-terminal sex hormone binding globulin (SHBG)-like domain and subsequently activates downstream signaling molecules, including PI3K, Rap1, and Akt. PI3K/Akt activation leads to propagation of αIIbβ3 outside-in signaling [164]. There are some transmembrane proteins, such as Semaphorin 4D [165] and the signaling lymphocyte activation molecule (SLAM) [166, 167], that regulate integrin αIIbβ3 outside-in signaling in platelets.

Intracellular adaptor molecules

Some intracellular adaptor molecules, such as the heterotrimeric guanine nucleotide-binding protein (G protein) Gα13 [168, 169], vacuolar protein sorting-associated protein 33B (VPS33B) [170], the SH2 domain-containing leukocyte protein of 76 kDa (SLP-76) [171], myosin [172], Src homology 2 domain-containing transforming protein (Shc) [173], Grb2 [174], FcγRIIa [175], lymphocyte adaptor protein (Lnk) [176], stress-activated protein kinase-interacting protein (Sin1) [177], Disabled-2 (Dab2) [178, 179], NLRP3 [13], and Wiskott-Aldrich syndrome protein (WASP) [180], are believed to be involved in integrin αIIbβ3 outside-in signaling. Gα13 directly binds to the integrin β3 cytoplasmic tail [168]. The spreading of CHO cells expressing αIIbβ3 on immobilized fibrinogen is inhibited by Gα13 siRNA interference. Gong et al. reported that platelets transfected with Gα13 siRNA spread poorly on immobilized fibrinogen and fail to activate Src. The myr-FEEERA peptide disrupted the Gα13/β3 interaction, thereby hampering Src activation and ultimately inhibiting αIIbβ3 outside-in signaling [181]. VPS33B, a member of the Sec1/Munc18 family, binds directly to integrin β3. Overexpression of VPS33B in CHO cells potentiated αIIbβ3 outside-in signaling but not inside-out signaling [170]. VPS33B was recently shown to function upstream of the RhoA-ROCK-MLC and Rac1-dependent pathways that lead to clot retraction and cell spreading [170]. SLP-76−/− murine platelets have normal fibrinogen binding but poor spreading. In the absence of SLP-76, collagen-induced platelet aggregation and granule release, as well as the phosphotyrosine of the β3 tail, are markedly impaired [182, 183]. Myosin is known to be able to bind to the NPXY motif within β integrin cytoplasmic domains [184]. Outside-in signaling events, such as integrin β3 phosphorylation, PI-4,5-P accumulation following stimulation, and FeCl3-induced thrombus formation, are strongly impaired in myosin-deficient mice [172]. Fibrinogen binding to platelet αIIbβ3 induces integrin cytoplasmic domain-dependent phosphorylation of FcγRIIa, which plays an important role in αIIbβ3-mediated outside-in signaling [175]. Platelets from Lnk−/−mice exhibit reduced abilities in terms of full spreading on fibrinogen, fibrin clot retraction, platelet aggregation, and stable thrombus formation. Lnk is thought to mediate αIIbβ3-dependent outside-in signaling through facilitating Src phosphorylation of Fyn [176]. Shc and Grb2 are known adaptor proteins that associate with the phosphorylated β3 tails involved in outside-in signaling [173]. Disabled-2 (Dab2) is known to be expressed in megakaryocytes and platelets. Dab2 has two isoforms: p82 and p59. Ser24 of Dab2 is phosphorylated by PKCβII, PKCγ, and PKCδ, which interact with integrin β3 and ultimately inhibit integrin αIIbβ3 activation [178]. The balance between the two isoforms of Dab2 controls integrin αIIbβ3 outside-in signaling [178]. NLRP3 regulates platelet integrin αIIbβ3 outside-in signaling by decreasing thrombin-induced phosphorylation of Src/Syk/PLCγ2 [13]. Data from WASP−/− mice showed that integrin αIIbβ3 outside-in signaling, such as fibrinogen and JON/A binding under agonist stimulation, is normal, whereas integrin αIIbβ3 outside-in signaling-dependent events, such as spreading on immobilized fibrinogen, fibrin clot retraction, and rebleeding, are impaired [180]. Some extracellular materials, pathogens, and other factors, such as amyloid-β [185], UV [186], Mucor circinelloides [187], heparin [188], and hypoxia [189], also regulate αIIbβ3 signaling. Peroxisome proliferator-activated receptor γ (PPARγ) [190], reelin [191, 192], and disulfide isomerase [193] were also reported to be involved in integrin αIIbβ3 outside-in signaling.

Kinases, phosphatases, and Rho-family small GTPases

The maintenance of normal platelet integrin αIIbβ3 signal transduction depends on numerous kinases and phosphatases that participate in the cascade of phosphorylation and dephosphorylation. To date, more than 10 enzymes have been reported to be involved in integrin αIIbβ3 outside-in signaling. The earliest phosphorylation event after fibrinogen binding to αIIbβ3 is the activation of Src kinase. Src has been reported to directly and constitutively associate with arginine-glycine-threonine (RGT) residues of the integrin β3 cytoplasmic tail via its SH3 domain [194, 195]. In resting platelets, integrin αIIbβ3-associated Src may not be activated because tyr418 of the Src activation loop is not phosphorylated and because its SH2 domain binds to phospho-tyr529. Phosphorylation of tyr529 is maintained by C-terminal Src kinase (Csk). Interestingly, RGT-containing peptides have the ability to abrogate the interaction of Src with β3 and thus selectively inhibit integrin αIIbβ3 outside-in signaling in platelets [196, 197]. Furthermore, experimental data from the β3 (Δ760-762) knockin mouse has demonstrated that deletion of RGT residues of β3 disrupts Src-mediated αIIbβ3 signaling [198].

Following platelet activation by agonists, fibrinogen binds to αIIbβ3 and then results in tyr529 of Src being dephosphorylated by protein-tyrosine phosphatase-1B (PTP-1B) [199]. After Src activation, Syk is recruited to the β3 tail and activated by Src [200]. Some adaptor molecules, such as SLP-76, Vav1, Vav2, Val3, and SLAP-130, are downstream of Syk in αIIbβ3 outside-in signaling [171, 201, 202]. There are some controversies concerning the role of Syk in αIIbβ3 outside-in signaling. Syk−/−platelets adhere normally to immobilized fibrinogen [203] and fail to show appropriate aggregation responses in collagen, but thrombin-stimulated responses remain normal [204, 205].

Twelve isoforms of the PKC family are involved in most platelet functions required for thrombus formation [206]. Recent data have demonstrated that individual PKC isoforms play highly specific roles in regulating platelet functions. PKCα is an essential positive regulator of granule secretion and secretion-dependent aggregation [207, 208]. The interaction of PKCβ with αIIbβ3 is regulated by integrin occupancy, and the interaction is required for platelet αIIbβ3 outside-in signaling [209]. PKCδ−/−mice showed that PKCδ is a key negative regulator of filopodial formation, and a lack of PKCδ leads to enhanced platelet aggregation [210]. However, Chari et al. have reported that there is no significant difference in thrombus formation ability in the injured artery in PKCδ−/− mice compared to that in wild-type mice [211]. PKCθ is constitutively associated with αIIbβ3 in human and murine platelets [160]. PKCθ is an important positive regulator in signaling between integrin αIIbβ3 and the actin cytoskeleton during platelet spreading on fibrinogen [212, 213], but not during spreading on collagen-related peptide (CRP) or collagen [213]. PKCθ−/− mice have shown that PKCθ negatively regulates thrombus formation on collagen under flow [213]. However, PKCι/λ−/− mice show that PKCι/λ is dispensable for αIIbβ3 bidirectional signaling [206]. Studies on murine Src homology 2 domain-containing inositol 5-phosphatase (SHIP1) knockout platelets have demonstrated that this enzyme regulates αIIbβ3-mediated platelet spreading through phosphatidylinositol (3,4,5)-triphosphate (PI (3,4,5) P3) and Src family kinases, as well as Lyn and calcium oscillation [214]. PI (3,4,5) P3 binds to Rasa3 and reduces Rasa3 Rap1GAP activity, thus facilitating CalDAG-GEFI-mediated Rap1 activation and regulation of αIIbβ3 outside-in signaling [215]. The activation of PI3K and internal calcium pathways are thought to be crucial for αIIbβ3 outside-in signaling [216]. PI3Kγ−/− platelets have demonstrated a diminished ability to reorganize the cytoskeleton, spread on fibrinogen, and form stable thrombi in vivo using a FeCl3-induced carotid injury model [217, 218]. The absence of PI3Kα leads to a reduction in thrombus size and increased arterial occlusion time but does not alter the tail bleeding time [219]. The E3 protein-ubiquitin ligase c-Cbl associates with the class I PI3K p85 regulatory subunit, regulating αIIbβ3 integrin outside-in signaling through Src family kinase (SFKs), Syk, and Pyk2 [19]. Pyk2−/− platelets show a significant defect in integrin αIIbβ3 outside-in signaling, similar to the loss of c-Cbl or PI3Kβ activity [220223]. Group IVA cytosolic phospholipase A2 (cPLA2α) and vimentin, a cPLA2α binding partner, are constitutively associated with αIIbβ3 in mouse and human platelets [224]. The data from the cPLA2α−/−platelets demonstrated that αIIbβ3 outside-in signaling was impaired and inside-out signaling was partially impaired [224, 225]. Khatlani et al. recently reported that the interaction of the catalytic subunit of protein phosphatase 2A (PP2Ac) with the adaptor protein Cbl-interacting protein of 85 kDa (CIN85) supports integrin αIIbβ3 outside-in signaling by suppressing phosphatase activity [226]. The Rho-family GTPases RhoA [227], Ras-related C3 botulinum toxin substrate 1 (Rac1) [228], and cell division control protein 42 (Cdc42) [229] are important for integrin-mediated platelet shape changes, but their precise role in αIIbβ3 outside-in signaling has been controversial [19].

Therapeutic agents targeting integrin αIIbβ3 in clinical use

Therapeutic agents targeting integrin αIIbβ3, both approved for clinical use and under development, are shown in Table 2. Currently, three therapeutic agents, consisting of integrin αIIbβ3 antagonists, the antibody fragment abciximab, and two small molecule inhibitors (eptifibatide and tirofiban), have been approved for clinical use in most countries. Abciximab (Reopro) is the Fab fragment of the mouse/human chimeric monoclonal antibody 7E3 that binds to an epitope near the ligand binding site of integrin β3. The steric hindrance resulting from the binding of abciximab to integrin αIIbβ3 prevents the interaction of fibrinogen and other ligands with integrin αIIbβ3, interfering with platelet aggregation and thrombosis. Abciximab has a nearly equal affinity for blocking either integrin αIIbβ3 or αvβ3 [230]. In addition, abciximab also reacts with a member of the β2 integrin subfamily of leukocyte integrins, called Mac-1 (CD11b/CD18, αMβ2) [231]. This feature gives abciximab anti-inflammatory and antiproliferative properties, but the clinical implications are unclear. Eptifibatide (Integrilin) is an 832 Da cyclic heptapeptide containing a lysine-glycine-aspartic acid (KGD) sequence, based on the structure of snake venom barbourin [232]. Tirofiban (Aggrastat) is a 495 Da synthetic compound (an l-tyrosine derivative) that acts as an RGD mimetic. The EPIC trial showed a reduced frequency of restenosis in high-risk angioplasty patients who received abciximab infusion [233]. Three phase 3 clinical trials (EPIC, EPILOG, and CAPTURE) showed that abciximab is effective in the prevention of ischemic cardiac complications, either in patients undergoing percutaneous coronary intervention or in patients with unstable angina (UA)/non-ST-elevation myocardial infarction (NSTMI) that was unresponsive to conventional therapy [234]. In recent years, tirofiban and eptifibatide have been introduced in clinical practice. Eptifibatide and tirofiban have also been approved for use in unstable angina, as well as angioplasty. The STRATEGY, MULTI-STRATEGY, and EVA-AMI trials demonstrated similar clinical outcomes between eptifibatide and abciximab in patients undergoing primary angioplasty [230]. Eptifibatide and tirofiban were developed to be used in patients with acute coronary syndrome (ACS) as a bridging therapy to revascularization. Eptifibatide and tirofiban were used directly in the catheterization laboratory immediately prior to PCI [235]. All three integrin αIIbβ3 antagonists are administered intravenously, but several oral active agents have been extensively investigated. Orbofiban, sibrafiban, xemilofiban, lefradafiban, and roxifiban are all experienced on phase II or phase III clinical trials. However, these oral αIIbβ3 antagonists are associated with a prolonged bleeding time, an increase in the incidence of thrombocytopenia, and a 30–35% increase in mortality, including cardiovascular mortality, potentially outweighing the beneficial effects [236]. Orally active antagonists have not yet been approved due to these adverse effects, as well as the fact that oral antagonists have exhibited no significant advantage compared to aspirin in large-scale clinical trials (totaling 33,326 subjects) [237]. For a more in-depth examination of integrin αIIbβ3 antagonists, several comprehensive reviews have been selected for further reading [238240]. In addition to integrin αIIbβ3 antagonists, some potential therapeutic agents (cilengitide, MRL-123) targeting the integrin αvβ3 molecule have been extensively investigated for anti-cancer or osteoporosis [238].
Table 2

Therapeutic agents targeting the integrin αIIbβ3 molecule in clinical use and preclinical studies

Class

Agent

Synonyms

Status

References

Monoclonal antibody

Abciximab

ReoPro, Clotinab, CentoRx

Approved

[230]

YM337

Null

No development reported

[258]

KGD sequence

Eptifibatide

Intrifiban, SB-1, Sch-60936, Integrilin

Approved

[232]

RGD sequence

MK-0852

L-367073

No development reported

[259]

G4120

Null

No development reported

[260]

DMP-728

Null

No development reported

[261]

Nonpeptide inhibitors

Tirofiban

L-700462, MK-383, Aggrastat

Approved

[262]

Lamifiban

Ro-449883

Not approved

[263]

GR144053

Null

No development reported

[264]

Oral agents

Xemilofiban

SC-54684; SC-54701 is the active component of xemilofiban

Not approved

[265]

Orbofiban

SC-57099B, CS-511; SC-57101 is the active component of orbofiban

Not approved

[266]

Sibrafiban

Null

Not approved

[267]

Lotrafiban

Null

Not approved

[268]

Lefradafiban

BiBu-104; fradafiban is the active component of lefradafiban

Not approved

[238]

Roxifiban

DMP754

Not approved

[269]

Cromafiban

CT-50352

Not approved

[238]

FK-633

Null

Not approved

[238]

Elarofiban

RWJ-53308

Not approved

[238, 270]

SR-121787

Null

Not approved

[238, 271]

Alnidofibatide

PRP-109891, Klerval

Not approved

[272]

Others

ANTP266

Null

Preclinical studies

[246]

RUC-1, RUC-2

Null

Preclinical studies

[273, 274]

PLT/uPA-T

Null

Preclinical studies

[244]

scFvSCE5-scuPA

Null

Preclinical studies

[243]

Targ-CD39

Null

Preclinical studies

[275]

myr-FEEERA

Null

Preclinical studies

[181]

RGT-containing peptides

Null

Preclinical studies

[196, 197]

Innovative agents/concepts targeting integrin αIIbβ3 and its signaling pathways

Because of the marked inhibition of platelet function, integrin αIIbβ3 antagonists can increase bleeding risk, although many studies suggest that these antagonists do not significantly increase the risk of life-threatening bleeding when compared to standard unfractionated heparin [235]. Severe thrombocytopenia is associated with all three currently approved integrin αIIbβ3 antagonists [241]. Thus, integrin αIIbβ3 antagonists must act in a narrow therapeutic window to prevent uncontrolled bleeding. The integrin αIIbβ3 antagonists currently in clinical use have been reported to cause conformational changes of αIIbβ3, inducing fibrinogen binding (priming) and eliciting outside-in signaling, thereby causing paradoxical platelet activation [242]. Currently, three novel and attractive concepts for avoiding bleeding risk are under development. (1) The single-chain variable fragment (scFv) of anti-integrin αIIbβ3 fused to an anticoagulant, fibrinolytic drugs, and CD39 is being developed. In preclinical studies, the prodrugs PLT/uPA-T and scFvSCE5-scuPA effectively inhibited thrombosis without affecting hemostasis [243, 244]. Targ-CD39 (CD39 recombinantly fused to an activated αIIbβ3-specific scFv) also demonstrates strong antithrombotic potency without hemostatic disturbance [245]. (2) Small molecules, such as RUC-1 and RUC-2, which selectively inhibit αIIbβ3 binding to fibrinogen to avoid a conformational change of the integrin αIIbβ3, are also being developed. Unlike classic agents, RUC-1 and RUC-2 bind to the metal ion binding site of β3 to inhibit fibrinogen binding. RUC-1 and RUC-2 do not induce a conformational change of integrin β3. As a result, they do not “prime” αIIbβ3 to bind its ligands. These small molecules that selectively inhibit fibrinogen binding to integrin αIIbβ3 have shown potent antithrombotic effects with low bleeding risk [246, 247]. (3) Targeting the integrin αIIbβ3 outside-in signaling pathways instead of the integrin αIIbβ3 molecule itself is another approach. Transgenic animals with impaired integrin αIIbβ3 outside-in signaling displayed a similar phenotype of reduced thrombosis potential, without excessive bleeding [248]. Thus, blocking integrin αIIbβ3 outside-in signaling has a potential advantage for the design of new antithrombotic therapies. A major advantage of targeting integrin αIIbβ3 outside-in signaling may be unaffected primary platelet adhesion and the first wave of reversible aggregation, which is critical for hemostasis but can reduce the size of a thrombus to prevent vessel occlusion [181, 196]. A recent study showed that the myr-FEEERA peptide selectively inhibits the Gα13-integrin β3 interaction, ultimately impairing Src activation and thereby inhibiting integrin αIIbβ3 outside-in signaling [181]. Both eptifibatide and the myr-FEEERA peptide inhibit laser-induced arteriolar thrombosis and FeCl3-induced occlusive carotid artery thrombosis. Eptifibatide also dramatically prolongs tail bleeding and increases blood loss; however, the myr-FEEERA peptide had no such adverse side effects [181]. Our studies have demonstrated that RGT-containing peptides have the ability to selectively inhibit integrin αIIbβ3 outside-in signaling through physical dissociation of the Src/β3 interaction in platelets [196, 197]. The results from ex vivo flow-based assays show that RGT-containing peptides inhibit thrombus formation under high shear rates but not under intermediate or low shear rates. The RGT peptide, its derivatives, and its analogs may have the potential to be developed into novel antithrombotic agents that specifically disrupt integrin αIIbβ3 outside-in signaling. However, it is still important to consider and investigate potential off-target effects caused by selective targeting of the Gα13-β3 and Src-β3 interactions.

Conclusions

The development of proteomics, biophysics, and gene knockout/knockin technologies has uncovered an increasing number of proteins that participate in the bidirectional signaling of integrin αIIbβ3 and has begun to shed light on their mechanisms and roles in regulating integrin αIIbβ3 signaling. Given the importance of integrin αIIbβ3 bidirectional signaling in maintaining proper platelet function, examining the complex regulatory relationship between these interacting proteins can prove immensely important for understanding the mechanisms of platelet activity, as well as for developing new therapies for cancer and thrombosis based on a deeper knowledge of the underlying physiology. Until now, the complex stoichiometric and spatiotemporal dynamics between integrin αIIbβ3 and its regulatory proteins have remained obscure, but promising new techniques have already presented new opportunities to learn more. Considerable efforts are still needed to fully explore how integrin αIIbβ3 interacts with its regulatory proteins, how its regulatory proteins interact with one another in space and time, and how therapeutic agents targeting integrin αIIbβ3 and its pathways can provide therapeutic benefits while minimizing adverse side effects.

Notes

Abbreviations

5-TH: 

5-Hydroxytryptamine

ACS: 

Acute coronary syndrome

ADAP: 

A hematopoietic-specific adapter protein

ADP: 

Adenosine diphosphate

BiFC: 

Bimolecular fluorescence complementation

CalDAG-GEFI: 

Ca2+ diacylglycerol guanine-nucleotide-exchange factor I

Cdc42: 

Cell division control protein 42

CEACAM-1: 

Carcinoembryonic antigen-related cell adhesion molecule-1

CHO: 

Chinese hamster ovary

CIB1: 

Calcium- and integrin-binding protein 1

CIN85: 

Cbl-interacting protein of 85 kDa

cPLA2α: 

Group IVA cytosolic phospholipase A2

CRP: 

Collagen-related peptide

Csk: 

C-terminal Src kinase

CTX: 

Cortical thymocyte marker of Xenopus

Dab2: 

Disabled-2

DAG: 

Diacylglycerol

Dok: 

Docking protein

EPIC: 

European Prevalence of Infection in Intensive Care

ESAM: 

Endothelial cell specific adhesion molecule

FAK: 

Focal adhesion kinase

FcRγ: 

Fc receptor γ-chain

FERM: 

4.1, Ezrin, radixin, moesin

Gas6: 

Growth arrest specific protein 6

GP: 

Glycoprotein

GPCR: 

G protein-coupled seven-transmembrane domain receptor

Grb2: 

Growth factor receptor bound protein 2

GT: 

Glanzmann’s thrombasthenia

HPC: 

Hematopoietic progenitor cell

HSC: 

Hematopoietic stem cell

IBS: 

Integrin-binding site

ICln: 

Chloride channel regulatory protein

ILK: 

Integrin-linked kinase

IP3: 

Inositol (1,4,5)-triphosphate

IP3-R: 

P3 receptor

IPP: 

ILK/PINCH/parvin

ITAM: 

Immunoreceptor tyrosine-based activation motif

ITIM: 

Immunoreceptor tyrosine-based inhibitory motif

JAM-A: 

Junctional adhesion molecule-A

KGD: 

Lysine-glycine-aspartic acid

Lnk: 

Lymphocyte adaptor protein

mAb: 

Monoclonal antibody

MEKK3: 

Mitogen-activated protein kinase/extracellular-regulated kinase kinase kinase-3

MRL: 

Mig-10/RIAM/lamellipodin

NLRP3: 

NACHT, LRR, and PYD domain-containing protein 3

NSTMI: 

Non-ST-elevation myocardial infarction

PCI: 

Percutaneous coronary intervention

PDK1: 

3-Phosphoinositide-dependent protein kinase-1

PECAM-1: 

Platelet endothelial cell adhesion molecule-1

PI3K: 

Phosphatidylinositol-3-kinase

PI-4,5-P: 

Phosphatidylinositol (4,5)-bisphosphate

PIPK1γ: 

Phosphatidylinositol 4-phosphate 5-kinase isoform 1γ

PKC: 

Protein kinase C

PMA: 

Phorbol 12-myristate 13-acetate

PP1cγ: 

Catalytic subunit of protein phosphatase 1 γ

PP2Ac: 

Catalytic subunit of protein phosphatase 2A

PPARγ: 

Peroxisome proliferator-activated receptor γ

PTB: 

Phosphotyrosine-binding domain

PTEN: 

Phosphatase and tensin homolog deleted on chromosome ten

PTP-1B: 

Protein-tyrosine phosphatase-1B

PXN: 

Paxillin

Pyk2: 

Proline-rich tyrosine kinase 2

Rac1: 

Ras-related C3 botulinum toxin substrate 1

RGT: 

Arginine-glycine-threonine

RhoA: 

Rho-family GTPase

RIAM: 

Rap1-GTP-interacting adaptor molecule

SFK: 

Src family kinase

SHBG: 

Sex hormone binding globulin

Shc: 

Src homology 2 domain-containing transforming protein

SHIP: 

Src homology 2 domain-containing inositol 5-phosphatase

Sin1: 

Stress-activated protein kinase-interacting protein

SLAM: 

Signaling lymphocyte activation molecule

SLP-76: 

SH2 domain-containing leukocyte protein of 76 kDa

Syk: 

Spleen tyrosine kinase

TM: 

Transmembrane

TSSC6: 

Tumor suppressing subtransferable candidate 6

TXA2: 

Thromboxane A2

UA: 

Unstable angina

UV: 

Ultraviolet

VEGF: 

Vascular endothelial growth factor

VPS33B: 

Vacuolar protein sorting-associated protein 33b

vWF: 

von Willebrand factor

WASP: 

Wiskott-Aldrich syndrome protein

Declarations

Acknowledgments

We thank all of our laboratory members for helpful discussion.

Funding

This study was supported by grants from the National Natural Science Foundation of China (81820108004, 81470305, 81670127, 81770624, and 81860490).

Availability of data and materials

All data and materials supporting the conclusions of this study have been included within the article.

Authors’ contributions

JH, XL, and XX were responsible for the conception and drafting of the manuscript and figures. JJ reviewed the articles to prepare this manuscript and participated in the discussion. All authors revised the manuscript. All authors read and approved the final manuscript.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors’ Affiliations

(1)
Department of Hematology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
(2)
Key Laboratory of Hematologic Malignancies, Diagnosis and Treatment, Hangzhou, Zhejiang, China
(3)
Institute of Hematology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
(4)
Department of Hematology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu, China
(5)
Department of Hematological Malignancies Translational Science, Gehr Family Center for Leukemia Research, Hematologic Malignancies and Stem Cell Transplantation Institute, Beckman Research Institute, City of Hope Medical Center, Duarte, CA 91010, USA
(6)
Department of Pathology, The Fourth Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
(7)
Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
(8)
State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Collaborative Innovation Center of Hematology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
(9)
Sino-French Research Centre for Life Sciences and Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
(10)
Department of Hematology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
(11)
Clinical Prenatal Diagnosis Center, Women’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China

References

  1. Hynes RO. Integrins: bidirectional, allosteric signaling machines. Cell. 2002;110(6):673–87.PubMedView ArticleGoogle Scholar
  2. Staatz WD, Rajpara SM, Wayner EA, Carter WG, Santoro SA. The membrane glycoprotein Ia-IIa (VLA-2) complex mediates the Mg++-dependent adhesion of platelets to collagen. J Cell Biol. 1989;108(5):1917–24.PubMedView ArticleGoogle Scholar
  3. Piotrowicz RS, Orchekowski RP, Nugent DJ, Yamada KY, Kunicki TJ. Glycoprotein Ic-IIa functions as an activation-independent fibronectin receptor on human platelets. J Cell Biol. 1988;106(4):1359–64.PubMedView ArticleGoogle Scholar
  4. Ill CR, Engvall E, Ruoslahti E. Adhesion of platelets to laminin in the absence of activation. J Cell Biol. 1984;99(6):2140–5.PubMedView ArticleGoogle Scholar
  5. Sonnenberg A, Modderman PW, Hogervorst F. Laminin receptor on platelets is the integrin VLA-6. Nature. 1988;336(6198):487–9.PubMedView ArticleGoogle Scholar
  6. Bennett JS, Chan C, Vilaire G, Mousa SA, DeGrado WF. Agonist-activated αvβ3 on platelets and lymphocytes binds to the matrix protein osteopontin. J Biol Chem. 1997;272(13):8137–40.PubMedView ArticleGoogle Scholar
  7. Paul BZ, Vilaire G, Kunapuli SP, Bennett JS. Concurrent signaling from Gαq- and Gαi-coupled pathways is essential for agonist-induced αvβ3 activation on human platelets. J Thromb Haemost. 2003;1(4):814–20.PubMedView ArticleGoogle Scholar
  8. Lavergne M, Janus-Bell E, Schaff M, Gachet C, Mangin PH. Platelet integrins in tumor metastasis: do they represent a therapeutic target? Cancers (Basel). 2017;9(10):133.Google Scholar
  9. Springer TA, Zhu J, Xiao T. Structural basis for distinctive recognition of fibrinogen γC peptide by the platelet integrin αIIbβ3. J Cell Biol. 2008;182(4):791–800.PubMedPubMed CentralView ArticleGoogle Scholar
  10. Nurden AT, Caen JP. An abnormal platelet glycoprotein pattern in three cases of Glanzmann’s thrombasthenia. Br J Haematol. 1974;28(2):253–60.PubMedView ArticleGoogle Scholar
  11. George JN, Caen JP, Nurden AT. Glanzmann’s thrombasthenia: the spectrum of clinical disease. Blood. 1990;75(7):1383–95.PubMedGoogle Scholar
  12. Zhou L, Jiang M, Shen H, You T, Ding Z, Cui Q, et al. Clinical and molecular insights into Glanzmann’s thrombasthenia in China. Clin Genet. 2018;94(2):213–20.PubMedView ArticleGoogle Scholar
  13. Qiao J, Wu X, Luo Q, Wei G, Xu M, Wu Y, et al. NLRP3 regulates platelet integrin αIIbβ3 outside-in signaling, hemostasis and arterial thrombosis. Haematologica. 2018;103(9):1568–76.PubMedPubMed CentralView ArticleGoogle Scholar
  14. Wagner CL, Mascelli MA, Neblock DS, Weisman HF, Coller BS, Jordan RE. Analysis of GPIIb/IIIa receptor number by quantification of 7E3 binding to human platelets. Blood. 1996;88(3):907–14.PubMedGoogle Scholar
  15. Woods VL Jr, Wolff LE, Keller DM. Resting platelets contain a substantial centrally located pool of glycoprotein IIb-IIIa complex which may be accessible to some but not other extracellular proteins. J Biol Chem. 1986;261(32):15242–51.PubMedGoogle Scholar
  16. Wencel-Drake JD, Plow EF, Kunicki TJ, Woods VL, Keller DM, Ginsberg MH. Localization of internal pools of membrane glycoproteins involved in platelet adhesive responses. Am J Pathol. 1986;124(2):324–34.PubMedPubMed CentralGoogle Scholar
  17. Amirkhosravi A, Amaya M, Siddiqui F, Biggerstaff JP, Meyer TV, Francis JL. Blockade of GpIIb/IIIa inhibits the release of vascular endothelial growth factor (VEGF) from tumor cell-activated platelets and experimental metastasis. Platelets. 1999;10(5):285–92.PubMedView ArticleGoogle Scholar
  18. Campbell ID, Humphries MJ. Integrin structure, activation, and interactions. Cold Spring Harb Perspect Biol. 2011;3(3):a004994.Google Scholar
  19. Durrant TN, van den Bosch MT, Hers I. Integrin αIIbβ3 outside-in signaling. Blood. 2017;130(14):1607–19.PubMedPubMed CentralGoogle Scholar
  20. Ye F, Kim C, Ginsberg MH. Molecular mechanism of inside-out integrin regulation. J Thromb Haemost. 2011;9(Suppl 1):20–5.PubMedPubMed CentralView ArticleGoogle Scholar
  21. Ginsberg MH. Integrin activation. BMB Rep. 2014;47(12):655–9.PubMedPubMed CentralView ArticleGoogle Scholar
  22. Ye F, Snider AK, Ginsberg MH. Talin and kindlin: the one-two punch in integrin activation. Front Med. 2014;8(1):6–16.PubMedView ArticleGoogle Scholar
  23. Shattil SJ, Kim C, Ginsberg MH. The final steps of integrin activation: the end game. Nat Rev Mol Cell Biol. 2010;11(4):288–300.PubMedPubMed CentralView ArticleGoogle Scholar
  24. Nieswandt B, Varga-Szabo D, Elvers M. Integrins in platelet activation. J Thromb Haemost. 2009;7(Suppl 1):206–9.PubMedView ArticleGoogle Scholar
  25. Goksoy E, Ma YQ, Wang X, Kong X, Perera D, Plow EF, et al. Structural basis for the autoinhibition of talin in regulating integrin activation. Mol Cell. 2008;31(1):124–33.PubMedPubMed CentralView ArticleGoogle Scholar
  26. Anthis NJ, Wegener KL, Ye F, Kim C, Goult BT, Lowe ED, et al. The structure of an integrin/talin complex reveals the basis of inside-out signal transduction. EMBO J. 2009;28(22):3623–32.PubMedPubMed CentralView ArticleGoogle Scholar
  27. Critchley DR. Cytoskeletal proteins talin and vinculin in integrin-mediated adhesion. Biochem Soc Trans. 2004;32(Pt 5):831–6.PubMedView ArticleGoogle Scholar
  28. Garcia-Alvarez B, de Pereda JM, Calderwood DA, Ulmer TS, Critchley D, Campbell ID, et al. Structural determinants of integrin recognition by talin. Mol Cell. 2003;11(1):49–58.PubMedView ArticleGoogle Scholar
  29. Di Paolo G, Pellegrini L, Letinic K, Cestra G, Zoncu R, Voronov S, et al. Recruitment and regulation of phosphatidylinositol phosphate kinase type 1 γ by the FERM domain of talin. Nature. 2002;420(6911):85–9.PubMedView ArticleGoogle Scholar
  30. Ling K, Doughman RL, Firestone AJ, Bunce MW, Anderson RA. Type I γ phosphatidylinositol phosphate kinase targets and regulates focal adhesions. Nature. 2002;420(6911):89–93.PubMedView ArticleGoogle Scholar
  31. Wegener KL, Basran J, Bagshaw CR, Campbell ID, Roberts GC, Critchley DR, et al. Structural basis for the interaction between the cytoplasmic domain of the hyaluronate receptor layilin and the talin F3 subdomain. J Mol Biol. 2008;382(1):112–26.PubMedView ArticleGoogle Scholar
  32. Chen HC, Appeddu PA, Parsons JT, Hildebrand JD, Schaller MD, Guan JL. Interaction of focal adhesion kinase with cytoskeletal protein talin. J Biol Chem. 1995;270(28):16995–9.PubMedView ArticleGoogle Scholar
  33. Hemmings L, Rees DJ, Ohanian V, Bolton SJ, Gilmore AP, Patel B, et al. Talin contains three actin-binding sites each of which is adjacent to a vinculin-binding site. J Cell Sci. 1996;109(Pt 11):2715–26.PubMedGoogle Scholar
  34. Moes M, Rodius S, Coleman SJ, Monkley SJ, Goormaghtigh E, Tremuth L, et al. The integrin binding site 2 (IBS2) in the talin rod domain is essential for linking integrin β subunits to the cytoskeleton. J Biol Chem. 2007;282(23):17280–8.PubMedView ArticleGoogle Scholar
  35. Gingras AR, Ziegler WH, Frank R, Barsukov IL, Roberts GC, Critchley DR, et al. Mapping and consensus sequence identification for multiple vinculin binding sites within the talin rod. J Biol Chem. 2005;280(44):37217–24.PubMedView ArticleGoogle Scholar
  36. Nakazawa T, Tadokoro S, Kamae T, Kiyomizu K, Kashiwagi H, Honda S, et al. Agonist stimulation, talin-1, and kindlin-3 are crucial for αIIbβ3 activation in a human megakaryoblastic cell line, CMK. Exp Hematol. 2013;41(1):79–90.e1.PubMedView ArticleGoogle Scholar
  37. Haling JR, Monkley SJ, Critchley DR, Petrich BG. Talin-dependent integrin activation is required for fibrin clot retraction by platelets. Blood. 2011;117(5):1719–22.PubMedPubMed CentralView ArticleGoogle Scholar
  38. Kasirer-Friede A, Kang J, Kahner B, Ye F, Ginsberg MH, Shattil SJ. ADAP interactions with talin and kindlin promote platelet integrin αIIbβ3 activation and stable fibrinogen binding. Blood. 2014;123(20):3156–65.PubMedPubMed CentralView ArticleGoogle Scholar
  39. Ye F, Hu G, Taylor D, Ratnikov B, Bobkov AA, McLean MA, et al. Recreation of the terminal events in physiological integrin activation. J Cell Biol. 2010;188(1):157–73.PubMedPubMed CentralView ArticleGoogle Scholar
  40. Calderwood DA, Zent R, Grant R, Rees DJ, Hynes RO, Ginsberg MH. The talin head domain binds to integrin β subunit cytoplasmic tails and regulates integrin activation. J Biol Chem. 1999;274(40):28071–4.PubMedView ArticleGoogle Scholar
  41. Tadokoro S, Shattil SJ, Eto K, Tai V, Liddington RC, de Pereda JM, et al. Talin binding to integrin β tails: a final common step in integrin activation. Science. 2003;302(5642):103–6.PubMedView ArticleGoogle Scholar
  42. Petrich BG, Fogelstrand P, Partridge AW, Yousefi N, Ablooglu AJ, Shattil SJ, et al. The antithrombotic potential of selective blockade of talin-dependent integrin αIIbβ3 (platelet GPIIb-IIIa) activation. J Clin Invest. 2007;117(8):2250–9.PubMedPubMed CentralView ArticleGoogle Scholar
  43. Petrich BG, Marchese P, Ruggeri ZM, Spiess S, Weichert RA, Ye F, et al. Talin is required for integrin-mediated platelet function in hemostasis and thrombosis. J Exp Med. 2007;204(13):3103–11.PubMedPubMed CentralView ArticleGoogle Scholar
  44. Nieswandt B, Moser M, Pleines I, Varga-Szabo D, Monkley S, Critchley D, et al. Loss of talin1 in platelets abrogates integrin activation, platelet aggregation, and thrombus formation in vitro and in vivo. J Exp Med. 2007;204(13):3113–8.PubMedPubMed CentralView ArticleGoogle Scholar
  45. Stefanini L, Ye F, Snider AK, Sarabakhsh K, Piatt R, Paul DS, et al. A talin mutant that impairs talin-integrin binding in platelets decelerates αIIbβ3 activation without pathological bleeding. Blood. 2014;123(17):2722–31.PubMedPubMed CentralView ArticleGoogle Scholar
  46. Bledzka K, Bialkowska K, Nie H, Qin J, Byzova T, Wu C, et al. Tyrosine phosphorylation of integrin β3 regulates kindlin-2 binding and integrin activation. J Biol Chem. 2010;285(40):30370–4.PubMedPubMed CentralView ArticleGoogle Scholar
  47. Moser M, Nieswandt B, Ussar S, Pozgajova M, Fassler R. Kindlin-3 is essential for integrin activation and platelet aggregation. Nat Med. 2008;14(3):325–30.PubMedView ArticleGoogle Scholar
  48. Ma YQ, Qin J, Wu C, Plow EF. Kindlin-2 (Mig-2): a co-activator of β3 integrins. J Cell Biol. 2008;181(3):439–46.PubMedPubMed CentralView ArticleGoogle Scholar
  49. Montanez E, Ussar S, Schifferer M, Bosl M, Zent R, Moser M, et al. Kindlin-2 controls bidirectional signaling of integrins. Genes Dev. 2008;22(10):1325–30.PubMedPubMed CentralView ArticleGoogle Scholar
  50. Klapproth S, Moretti FA, Zeiler M, Ruppert R, Breithaupt U, Mueller S, et al. Minimal amounts of kindlin-3 suffice for basal platelet and leukocyte functions in mice. Blood. 2015;126(24):2592–600.PubMedView ArticleGoogle Scholar
  51. Gao J, Huang M, Lai J, Mao K, Sun P, Cao Z, et al. Kindlin supports platelet integrin αIIbβ3 activation by interacting with paxillin. J Cell Sci. 2017;130(21):3764–75.PubMedPubMed CentralView ArticleGoogle Scholar
  52. Harburger DS, Bouaouina M, Calderwood DA. Kindlin-1 and -2 directly bind the C-terminal region of β integrin cytoplasmic tails and exert integrin-specific activation effects. J Biol Chem. 2009;284(17):11485–97.PubMedPubMed CentralView ArticleGoogle Scholar
  53. Svensson L, Howarth K, McDowall A, Patzak I, Evans R, Ussar S, et al. Leukocyte adhesion deficiency-III is caused by mutations in KINDLIN3 affecting integrin activation. Nat Med. 2009;15(3):306–12.PubMedPubMed CentralView ArticleGoogle Scholar
  54. Moser M, Legate KR, Zent R, Fassler R. The tail of integrins, talin, and kindlins. Science. 2009;324(5929):895–9.PubMedView ArticleGoogle Scholar
  55. Lai-Cheong JE, Parsons M, McGrath JA. The role of kindlins in cell biology and relevance to human disease. Int J Biochem Cell Biol. 2010;42(5):595–603.PubMedView ArticleGoogle Scholar
  56. Meves A, Stremmel C, Gottschalk K, Fassler R. The Kindlin protein family: new members to the club of focal adhesion proteins. Trends Cell Biol. 2009;19(10):504–13.PubMedView ArticleGoogle Scholar
  57. Ussar S, Wang HV, Linder S, Fassler R, Moser M. The Kindlins: subcellular localization and expression during murine development. Exp Cell Res. 2006;312(16):3142–51.PubMedView ArticleGoogle Scholar
  58. Bialkowska K, Ma YQ, Bledzka K, Sossey-Alaoui K, Izem L, Zhang X, et al. The integrin co-activator Kindlin-3 is expressed and functional in a non-hematopoietic cell, the endothelial cell. J Biol Chem. 2010;285(24):18640–9.PubMedPubMed CentralView ArticleGoogle Scholar
  59. Zhou C, Song S, Zhang J. A novel 3017-bp deletion mutation in the FERMT1 (KIND1) gene in a Chinese family with Kindler syndrome. Br J Dermatol. 2009;160(5):1119–22.PubMedView ArticleGoogle Scholar
  60. Techanukul T, Sethuraman G, Zlotogorski A, Horev L, Macarov M, Trainer A, et al. Novel and recurrent FERMT1 gene mutations in Kindler syndrome. Acta Derm Venereol. 2011;91(3):267–70.PubMedView ArticleGoogle Scholar
  61. Kuijpers TW, van de Vijver E, Weterman MA, de Boer M, Tool AT, van den Berg TK, et al. LAD-1/variant syndrome is caused by mutations in FERMT3. Blood. 2009;113(19):4740–6.PubMedView ArticleGoogle Scholar
  62. Nagy M, Mastenbroek TG, Mattheij NJA, de Witt S, Clemetson KJ, Kirschner J, et al. Variable impairment of platelet functions in patients with severe, genetically linked immune deficiencies. Haematologica. 2018;103(3):540–9.PubMedPubMed CentralView ArticleGoogle Scholar
  63. Rognoni E, Ruppert R, Fassler R. The kindlin family: functions, signaling properties and implications for human disease. J Cell Sci. 2016;129(1):17–27.PubMedView ArticleGoogle Scholar
  64. McDowall A, Svensson L, Stanley P, Patzak I, Chakravarty P, Howarth K, et al. Two mutations in the KINDLIN3 gene of a new leukocyte adhesion deficiency III patient reveal distinct effects on leukocyte function in vitro. Blood. 2010;115(23):4834–42.PubMedView ArticleGoogle Scholar
  65. Wang P, Zhan J, Song J, Wang Y, Fang W, Liu Z, et al. Differential expression of Kindlin-1 and Kindlin-2 correlates with esophageal cancer progression and epidemiology. Sci China Life Sci. 2017;60(11):1214–22.PubMedView ArticleGoogle Scholar
  66. Dowling JJ, Gibbs E, Russell M, Goldman D, Minarcik J, Golden JA, et al. Kindlin-2 is an essential component of intercalated discs and is required for vertebrate cardiac structure and function. Circ Res. 2008;102(4):423–31.PubMedView ArticleGoogle Scholar
  67. Pluskota E, Dowling JJ, Gordon N, Golden JA, Szpak D, West XZ, et al. The integrin coactivator kindlin-2 plays a critical role in angiogenesis in mice and zebrafish. Blood. 2011;117(18):4978–87.PubMedPubMed CentralView ArticleGoogle Scholar
  68. Goult BT, Bouaouina M, Harburger DS, Bate N, Patel B, Anthis NJ, et al. The structure of the N-terminus of kindlin-1: a domain important for αIIbβ3 integrin activation. J Mol Biol. 2009;394(5):944–56.PubMedPubMed CentralView ArticleGoogle Scholar
  69. Bledzka K, Liu J, Xu Z, Perera HD, Yadav SP, Bialkowska K, et al. Spatial coordination of kindlin-2 with talin head domain in interaction with integrin β cytoplasmic tails. J Biol Chem. 2012;287(29):24585–94.PubMedPubMed CentralView ArticleGoogle Scholar
  70. Anthis NJ, Haling JR, Oxley CL, Memo M, Wegener KL, Lim CJ, et al. β Integrin tyrosine phosphorylation is a conserved mechanism for regulating talin-induced integrin activation. J Biol Chem. 2009;284(52):36700–10.PubMedPubMed CentralView ArticleGoogle Scholar
  71. Oxley CL, Anthis NJ, Lowe ED, Vakonakis I, Campbell ID, Wegener KL. An integrin phosphorylation switch: the effect of β3 integrin tail phosphorylation on Dok1 and talin binding. J Biol Chem. 2008;283(9):5420–6.PubMedView ArticleGoogle Scholar
  72. Li Z, Delaney MK, O’Brien KA, Du X. Signaling during platelet adhesion and activation. Arterioscler Thromb Vasc Biol. 2010;30(12):2341–9.PubMedPubMed CentralView ArticleGoogle Scholar
  73. Li H, Deng Y, Sun K, Yang H, Liu J, Wang M, et al. Structural basis of kindlin-mediated integrin recognition and activation. Proc Natl Acad Sci U S A. 2017;114(35):9349–54.PubMedPubMed CentralView ArticleGoogle Scholar
  74. Fukuda K, Bledzka K, Yang J, Perera HD, Plow EF, Qin J. Molecular basis of kindlin-2 binding to integrin-linked kinase pseudokinase for regulating cell adhesion. J Biol Chem. 2014;289(41):28363–75.PubMedPubMed CentralView ArticleGoogle Scholar
  75. Huet-Calderwood C, Brahme NN, Kumar N, Stiegler AL, Raghavan S, Boggon TJ, et al. Differences in binding to the ILK complex determines kindlin isoform adhesion localization and integrin activation. J Cell Sci. 2014;127(Pt 19):4308–21.PubMedPubMed CentralView ArticleGoogle Scholar
  76. Kasirer-Friede A, Moran B, Nagrampa-Orje J, Swanson K, Ruggeri ZM, Schraven B, et al. ADAP is required for normal αIIbβ3 activation by VWF/GP Ib-IX-V and other agonists. Blood. 2007;109(3):1018–25.PubMedPubMed CentralView ArticleGoogle Scholar
  77. Kasirer-Friede A, Ruggeri ZM, Shattil SJ. Role for ADAP in shear flow-induced platelet mechanotransduction. Blood. 2010;115(11):2274–82.PubMedPubMed CentralView ArticleGoogle Scholar
  78. Theodosiou M, Widmaier M, Bottcher RT, Rognoni E, Veelders M, Bharadwaj M, et al. Kindlin-2 cooperates with talin to activate integrins and induces cell spreading by directly binding paxillin. Elife. 2016;5:e10130.PubMedPubMed CentralView ArticleGoogle Scholar
  79. Sakata A, Ohmori T, Nishimura S, Suzuki H, Madoiwa S, Mimuro J, et al. Paxillin is an intrinsic negative regulator of platelet activation in mice. Thromb J. 2014;12(1):1.PubMedPubMed CentralView ArticleGoogle Scholar
  80. Honda S, Shirotani-Ikejima H, Tadokoro S, Maeda Y, Kinoshita T, Tomiyama Y, et al. Integrin-linked kinase associated with integrin activation. Blood. 2009;113(21):5304–13.PubMedView ArticleGoogle Scholar
  81. Shattil SJ, O’Toole T, Eigenthaler M, Thon V, Williams M, Babior BM, et al. β3-Endonexin, a novel polypeptide that interacts specifically with the cytoplasmic tail of the integrin β3 subunit. J Cell Biol. 1995;131(3):807–16.PubMedView ArticleGoogle Scholar
  82. Kashiwagi H, Schwartz MA, Eigenthaler M, Davis KA, Ginsberg MH, Shattil SJ. Affinity modulation of platelet integrin αIIbβ3 by β3-endonexin, a selective binding partner of the β3 integrin cytoplasmic tail. J Cell Biol. 1997;137(6):1433–43.PubMedPubMed CentralView ArticleGoogle Scholar
  83. Tsuboi S. Calcium integrin-binding protein activates platelet integrin αIIbβ3. J Biol Chem. 2002;277(3):1919–23.PubMedView ArticleGoogle Scholar
  84. Yuan W, Leisner TM, McFadden AW, Wang Z, Larson MK, Clark S, et al. CIB1 is an endogenous inhibitor of agonist-induced integrin αIIbβ3 activation. J Cell Biol. 2006;172(2):169–75.PubMedPubMed CentralView ArticleGoogle Scholar
  85. Larkin D, Murphy D, Reilly DF, Cahill M, Sattler E, Harriott P, et al. ICln, a novel integrin αIIbβ3-associated protein, functionally regulates platelet activation. J Biol Chem. 2004;279(26):27286–93.PubMedView ArticleGoogle Scholar
  86. Gushiken FC, Hyojeong H, Pradhan S, Langlois KW, Alrehani N, Cruz MA, et al. The catalytic subunit of protein phosphatase 1 γ regulates thrombin-induced murine platelet αIIbβ3 function. PLoS One. 2009;4(12):e8304.PubMedPubMed CentralView ArticleGoogle Scholar
  87. Ohmori T, Kashiwakura Y, Ishiwata A, Madoiwa S, Mimuro J, Honda S, et al. Vinculin activates inside-out signaling of integrin αIIbβ3 in Chinese hamster ovary cells. Biochem Biophys Res Commun. 2010;400(3):323–8.PubMedView ArticleGoogle Scholar
  88. Tucker KL, Sage T, Stevens JM, Jordan PA, Jones S, Barrett NE, et al. A dual role for integrin-linked kinase in platelets: regulating integrin function and α-granule secretion. Blood. 2008;112(12):4523–31.PubMedPubMed CentralView ArticleGoogle Scholar
  89. Jones CI, Tucker KL, Sasikumar P, Sage T, Kaiser WJ, Moore C, et al. Integrin-linked kinase regulates the rate of platelet activation and is essential for the formation of stable thrombi. J Thromb Haemost. 2014;12(8):1342–52.PubMedView ArticleGoogle Scholar
  90. Pasquet JM, Noury M, Nurden AT. Evidence that the platelet integrin αIIbβ3 is regulated by the integrin-linked kinase, ILK, in a PI3-kinase dependent pathway. Thromb Haemost. 2002;88(1):115–22.PubMedGoogle Scholar
  91. Sadoul K, Vignoud L, Mossuz P, Block MR. Proteolysis leads to the appearance of the long form of β3-endonexin in human platelets. Exp Cell Res. 2005;305(2):427–35.PubMedView ArticleGoogle Scholar
  92. Kracun D, Riess F, Kanchev I, Gawaz M, Gorlach A. The β3-integrin binding protein β3-endonexin is a novel negative regulator of hypoxia-inducible factor-1. Antioxid Redox Signal. 2014;20(13):1964–76.PubMedPubMed CentralView ArticleGoogle Scholar
  93. Naik MU, Naik TU, Summer R, Naik UP. Binding of CIB1 to the αIIb tail of αIIbβ3 is required for FAK recruitment and activation in platelets. PLoS One. 2017;12(5):e0176602.PubMedPubMed CentralView ArticleGoogle Scholar
  94. Lagarrigue F, Vikas Anekal P, Lee HS, Bachir AI, Ablack JN, Horwitz AF, et al. A RIAM/lamellipodin-talin-integrin complex forms the tip of sticky fingers that guide cell migration. Nat Commun. 2015;6:8492.PubMedPubMed CentralView ArticleGoogle Scholar
  95. Mitsios JV, Prevost N, Kasirer-Friede A, Gutierrez E, Groisman A, Abrams CS, et al. What is vinculin needed for in platelets? J Thromb Haemost. 2010;8(10):2294–304.PubMedPubMed CentralView ArticleGoogle Scholar
  96. Kato A, Kawamata N, Tamayose K, Egashira M, Miura R, Fujimura T, et al. Ancient ubiquitous protein 1 binds to the conserved membrane-proximal sequence of the cytoplasmic tail of the integrin α subunits that plays a crucial role in the inside-out signaling of αIIbβ3. J Biol Chem. 2002;277(32):28934–41.PubMedView ArticleGoogle Scholar
  97. Kiema T, Lad Y, Jiang P, Oxley CL, Baldassarre M, Wegener KL, et al. The molecular basis of filamin binding to integrins and competition with talin. Mol Cell. 2006;21(3):337–47.PubMedView ArticleGoogle Scholar
  98. McCleverty CJ, Lin DC, Liddington RC. Structure of the PTB domain of tensin1 and a model for its recruitment to fibrillar adhesions. Protein Sci. 2007;16(6):1223–9.PubMedPubMed CentralView ArticleGoogle Scholar
  99. Wegener KL, Partridge AW, Han J, Pickford AR, Liddington RC, Ginsberg MH, et al. Structural basis of integrin activation by talin. Cell. 2007;128(1):171–82.PubMedView ArticleGoogle Scholar
  100. Denofrio JC, Yuan W, Temple BR, Gentry HR, Parise LV. Characterization of calcium- and integrin-binding protein 1 (CIB1) knockout platelets: potential compensation by CIB family members. Thromb Haemost. 2008;100(5):847–56.PubMedPubMed CentralView ArticleGoogle Scholar
  101. Naik MU, Nigam A, Manrai P, Millili P, Czymmek K, Sullivan M, et al. CIB1 deficiency results in impaired thrombosis: the potential role of CIB1 in outside-in signaling through integrin αIIbβ3. J Thromb Haemost. 2009;7(11):1906–14.PubMedView ArticleGoogle Scholar
  102. Izard T, Vonrhein C. Structural basis for amplifying vinculin activation by talin. J Biol Chem. 2004;279(26):27667–78.PubMedView ArticleGoogle Scholar
  103. Calderwood DA, Fujioka Y, de Pereda JM, Garcia-Alvarez B, Nakamoto T, Margolis B, et al. Integrin β cytoplasmic domain interactions with phosphotyrosine-binding domains: a structural prototype for diversity in integrin signaling. Proc Natl Acad Sci U S A. 2003;100(5):2272–7.PubMedPubMed CentralView ArticleGoogle Scholar
  104. Chatterjee D, D’Souza A, Zhang Y, Bin W, Tan SM, Bhattacharjya S. Interaction analyses of 14-3-3ζ, Dok1, and phosphorylated integrin β cytoplasmic tails reveal a bi-molecular switch in integrin regulation. J Mol Biol. 2018;430(21):4419–30.PubMedView ArticleGoogle Scholar
  105. Niki M, Nayak MK, Jin H, Bhasin N, Plow EF, Pandolfi PP, et al. Dok-1 negatively regulates platelet integrin αIIbβ3 outside-in signalling and inhibits thrombosis in mice. Thromb Haemost. 2016;115(5):969–78.PubMedPubMed CentralView ArticleGoogle Scholar
  106. Hughan SC, Spring CM, Schoenwaelder SM, Sturgeon S, Alwis I, Yuan Y, et al. Dok-2 adaptor protein regulates the shear-dependent adhesive function of platelet integrin αIIbβ3 in mice. J Biol Chem. 2014;289(8):5051–60.PubMedPubMed CentralView ArticleGoogle Scholar
  107. Liu J, Das M, Yang J, Ithychanda SS, Yakubenko VP, Plow EF, et al. Structural mechanism of integrin inactivation by filamin. Nat Struct Mol Biol. 2015;22(5):383–9.PubMedPubMed CentralView ArticleGoogle Scholar
  108. Berrou E, Adam F, Lebret M, Planche V, Fergelot P, Issertial O, et al. Gain-of-function mutation in filamin A potentiates platelet integrin αIIbβ3 activation. Arterioscler Thromb Vasc Biol. 2017;37(6):1087–97.PubMedView ArticleGoogle Scholar
  109. Tadokoro S, Nakazawa T, Kamae T, Kiyomizu K, Kashiwagi H, Honda S, et al. A potential role for α-actinin in inside-out αIIbβ3 signaling. Blood. 2011;117(1):250–8.PubMedView ArticleGoogle Scholar
  110. Legate KR, Fassler R. Mechanisms that regulate adaptor binding to β-integrin cytoplasmic tails. J Cell Sci. 2009;122(Pt 2):187–98.PubMedView ArticleGoogle Scholar
  111. Shams H, Mofrad MRK. α-Actinin induces a kink in the transmembrane domain of β3-integrin and impairs activation via talin. Biophys J. 2017;113(4):948–56.PubMedPubMed CentralView ArticleGoogle Scholar
  112. Vanhoorelbeke K, Ulrichts H, Van de Walle G, Fontayne A, Deckmyn H. Inhibition of platelet glycoprotein Ib and its antithrombotic potential. Curr Pharm Des. 2007;13(26):2684–97.PubMedView ArticleGoogle Scholar
  113. Senis YA, Mazharian A, Mori J. Src family kinases: at the forefront of platelet activation. Blood. 2014;124(13):2013–24.PubMedPubMed CentralView ArticleGoogle Scholar
  114. Severin S, Nash CA, Mori J, Zhao Y, Abram C, Lowell CA, et al. Distinct and overlapping functional roles of Src family kinases in mouse platelets. J Thromb Haemost. 2012;10(8):1631–45.PubMedPubMed CentralView ArticleGoogle Scholar
  115. Li Z, Zhang G, Liu J, Stojanovic A, Ruan C, Lowell CA, et al. An important role of the SRC family kinase Lyn in stimulating platelet granule secretion. J Biol Chem. 2010;285(17):12559–70.PubMedPubMed CentralView ArticleGoogle Scholar
  116. Reddy KB, Smith DM, Plow EF. Analysis of Fyn function in hemostasis and αIIbβ3-integrin signaling. J Cell Sci. 2008;121(Pt 10):1641–8.PubMedPubMed CentralView ArticleGoogle Scholar
  117. Geue S, Walker-Allgaier B, Eissler D, Tegtmeyer R, Schaub M, Lang F, et al. Doxepin inhibits GPVI-dependent platelet Ca (2+) signaling and collagen-dependent thrombus formation. Am J Physiol Cell Physiol. 2017;312(6):C765–C74.PubMedView ArticleGoogle Scholar
  118. Suzuki-Inoue K, Inoue O, Frampton J, Watson SP. Murine GPVI stimulates weak integrin activation in PLCγ2−/− platelets: involvement of PLCγ1 and PI3-kinase. Blood. 2003;102(4):1367–73.PubMedView ArticleGoogle Scholar
  119. Ozaki Y, Asazuma N, Suzuki-Inoue K, Berndt MC. Platelet GPIb-IX-V-dependent signaling. J Thromb Haemost. 2005;3(8):1745–51.PubMedView ArticleGoogle Scholar
  120. Woulfe D, Jiang H, Mortensen R, Yang J, Brass LF. Activation of Rap1B by G(i) family members in platelets. J Biol Chem. 2002;277(26):23382–90.PubMedView ArticleGoogle Scholar
  121. Varga-Szabo D, Braun A, Nieswandt B. Calcium signaling in platelets. J Thromb Haemost. 2009;7(7):1057–66.PubMedView ArticleGoogle Scholar
  122. Cifuni SM, Wagner DD, Bergmeier W. CalDAG-GEFI and protein kinase C represent alternative pathways leading to activation of integrin αIIbβ3 in platelets. Blood. 2008;112(5):1696–703.PubMedPubMed CentralView ArticleGoogle Scholar
  123. Piatt R, Paul DS, Lee RH, McKenzie SE, Parise LV, Cowley DO, et al. Mice expressing low levels of CalDAG-GEFI exhibit markedly impaired platelet activation with minor impact on hemostasis. Arterioscler Thromb Vasc Biol. 2016;36(9):1838–46.PubMedPubMed CentralView ArticleGoogle Scholar
  124. Kato H, Nakazawa Y, Kurokawa Y, Kashiwagi H, Morikawa Y, Morita D, et al. Human CalDAG-GEFI deficiency increases bleeding and delays αIIbβ3 activation. Blood. 2016;128(23):2729–33.PubMedView ArticleGoogle Scholar
  125. Crittenden JR, Bergmeier W, Zhang Y, Piffath CL, Liang Y, Wagner DD, et al. CalDAG-GEFI integrates signaling for platelet aggregation and thrombus formation. Nat Med. 2004;10(9):982–6.PubMedView ArticleGoogle Scholar
  126. Harper MT, Poole AW. Diverse functions of protein kinase C isoforms in platelet activation and thrombus formation. J Thromb Haemost. 2010;8(3):454–62.PubMedView ArticleGoogle Scholar
  127. Han J, Lim CJ, Watanabe N, Soriani A, Ratnikov B, Calderwood DA, et al. Reconstructing and deconstructing agonist-induced activation of integrin αIIbβ3. Curr Biol. 2006;16(18):1796–806.PubMedView ArticleGoogle Scholar
  128. Konopatskaya O, Gilio K, Harper MT, Zhao Y, Cosemans JM, Karim ZA, et al. PKCα regulates platelet granule secretion and thrombus formation in mice. J Clin Invest. 2009;119(2):399–407.PubMedPubMed CentralGoogle Scholar
  129. Chrzanowska-Wodnicka M, Smyth SS, Schoenwaelder SM, Fischer TH, White GC 2nd. Rap1b is required for normal platelet function and hemostasis in mice. J Clin Invest. 2005;115(3):680–7.PubMedPubMed CentralView ArticleGoogle Scholar
  130. Lee HS, Lim CJ, Puzon-McLaughlin W, Shattil SJ, Ginsberg MH. RIAM activates integrins by linking talin to ras GTPase membrane-targeting sequences. J Biol Chem. 2009;284(8):5119–27.PubMedPubMed CentralView ArticleGoogle Scholar
  131. Stritt S, Wolf K, Lorenz V, Vogtle T, Gupta S, Bosl MR, et al. Rap1-GTP-interacting adaptor molecule (RIAM) is dispensable for platelet integrin activation and function in mice. Blood. 2015;125(2):219–22.PubMedPubMed CentralView ArticleGoogle Scholar
  132. Watanabe N, Bodin L, Pandey M, Krause M, Coughlin S, Boussiotis VA, et al. Mechanisms and consequences of agonist-induced talin recruitment to platelet integrin αIIbβ3. J Cell Biol. 2008;181(7):1211–22.PubMedPubMed CentralView ArticleGoogle Scholar
  133. Zhu L, Yang J, Bromberger T, Holly A, Lu F, Liu H, et al. Structure of Rap1b bound to talin reveals a pathway for triggering integrin activation. Nat Commun. 2017;8(1):1744.PubMedPubMed CentralView ArticleGoogle Scholar
  134. Lagarrigue F, Gingras AR, Paul DS, Valadez AJ, Cuevas MN, Sun H, et al. Rap1 binding to the talin 1 F0 domain makes a minimal contribution to murine platelet GPIIb-IIIa activation. Blood Adv. 2018;2(18):2358–68.PubMedPubMed CentralView ArticleGoogle Scholar
  135. Srinivasan S, Schiemer J, Zhang X, Chishti AH, Le Breton GC. Gα13 switch region 2 binds to the talin head domain and activates αIIbβ3 integrin in human platelets. J Biol Chem. 2015;290(41):25129–39.PubMedPubMed CentralView ArticleGoogle Scholar
  136. Wee JL, Jackson DE. The Ig-ITIM superfamily member PECAM-1 regulates the “outside-in” signaling properties of integrin αIIbβ3 in platelets. Blood. 2005;106(12):3816–23.PubMedView ArticleGoogle Scholar
  137. Wong C, Liu Y, Yip J, Chand R, Wee JL, Oates L, et al. CEACAM1 negatively regulates platelet-collagen interactions and thrombus growth in vitro and in vivo. Blood. 2009;113(8):1818–28.PubMedView ArticleGoogle Scholar
  138. Jones CI, Sage T, Moraes LA, Vaiyapuri S, Hussain U, Tucker KL, et al. Platelet endothelial cell adhesion molecule-1 inhibits platelet response to thrombin and von Willebrand factor by regulating the internalization of glycoprotein Ib via AKT/glycogen synthase kinase-3/dynamin and integrin αIIbβ3. Arterioscler Thromb Vasc Biol. 2014;34(9):1968–76.PubMedView ArticleGoogle Scholar
  139. Newland SA, Macaulay IC, Floto AR, de Vet EC, Ouwehand WH, Watkins NA, et al. The novel inhibitory receptor G6B is expressed on the surface of platelets and attenuates platelet function in vitro. Blood. 2007;109(11):4806–9.PubMedView ArticleGoogle Scholar
  140. Geer MJ, van Geffen JP, Gopalasingam P, Vogtle T, Smith CW, Heising S, et al. Uncoupling ITIM receptor G6b-B from tyrosine phosphatases Shp1 and Shp2 disrupts murine platelet homeostasis. Blood. 2018;132(13):1413–25.PubMedPubMed CentralView ArticleGoogle Scholar
  141. Mazharian A, Wang YJ, Mori J, Bem D, Finney B, Heising S, et al. Mice lacking the ITIM-containing receptor G6b-B exhibit macrothrombocytopenia and aberrant platelet function. Sci Signal. 2012;5(248):ra78.PubMedPubMed CentralView ArticleGoogle Scholar
  142. Hu M, Liu P, Liu Y, Yue M, Wang Y, Wang S, et al. Platelet Shp2 negatively regulates thrombus stability under high shear stress. J Thromb Haemost. 2019;17(1):220–31.PubMedView ArticleGoogle Scholar
  143. Naik UP, Ehrlich YH, Kornecki E. Mechanisms of platelet activation by a stimulatory antibody: cross-linking of a novel platelet receptor for monoclonal antibody F11 with the FcγRII receptor. Biochem J. 1995;310(Pt 1):155–62.PubMedPubMed CentralView ArticleGoogle Scholar
  144. Nasdala I, Wolburg-Buchholz K, Wolburg H, Kuhn A, Ebnet K, Brachtendorf G, et al. A transmembrane tight junction protein selectively expressed on endothelial cells and platelets. J Biol Chem. 2002;277(18):16294–303.PubMedView ArticleGoogle Scholar
  145. Stalker TJ, Wu J, Morgans A, Traxler EA, Wang L, Chatterjee MS, et al. Endothelial cell specific adhesion molecule (ESAM) localizes to platelet-platelet contacts and regulates thrombus formation in vivo. J Thromb Haemost. 2009;7(11):1886–96.PubMedPubMed CentralView ArticleGoogle Scholar
  146. Sobocka MB, Sobocki T, Babinska A, Hartwig JH, Li M, Ehrlich YH, et al. Signaling pathways of the F11 receptor (F11R; a.k.a. JAM-1, JAM-A) in human platelets: F11R dimerization, phosphorylation and complex formation with the integrin GPIIIa. J Recept Signal Transduct Res. 2004;24(1–2):85–105.PubMedView ArticleGoogle Scholar
  147. Naik MU, Caplan JL, Naik UP. Junctional adhesion molecule-A suppresses platelet integrin αIIbβ3 signaling by recruiting Csk to the integrin-c-Src complex. Blood. 2014;123(9):1393–402.PubMedPubMed CentralView ArticleGoogle Scholar
  148. Naik MU, Stalker TJ, Brass LF, Naik UP. JAM-A protects from thrombosis by suppressing integrin αIIbβ3-dependent outside-in signaling in platelets. Blood. 2012;119(14):3352–60.PubMedPubMed CentralView ArticleGoogle Scholar
  149. Orlowski E, Chand R, Yip J, Wong C, Goschnick MW, Wright MD, et al. A platelet tetraspanin superfamily member, CD151, is required for regulation of thrombus growth and stability in vivo. J Thromb Haemost. 2009;7(12):2074–84.PubMedView ArticleGoogle Scholar
  150. Lau LM, Wee JL, Wright MD, Moseley GW, Hogarth PM, Ashman LK, et al. The tetraspanin superfamily member CD151 regulates outside-in integrin αIIbβ3 signaling and platelet function. Blood. 2004;104(8):2368–75.PubMedView ArticleGoogle Scholar
  151. Goschnick MW, Lau LM, Wee JL, Liu YS, Hogarth PM, Robb LM, et al. Impaired “outside-in” integrin αIIbβ3 signaling and thrombus stability in TSSC6-deficient mice. Blood. 2006;108(6):1911–8.PubMedView ArticleGoogle Scholar
  152. Israels SJ, McMillan-Ward EM. CD63 modulates spreading and tyrosine phosphorylation of platelets on immobilized fibrinogen. Thromb Haemost. 2005;93(2):311–8.PubMedView ArticleGoogle Scholar
  153. Uchtmann K, Park ER, Bergsma A, Segula J, Edick MJ, Miranti CK. Homozygous loss of mouse tetraspanin CD82 enhances integrin αIIbβ3 expression and clot retraction in platelets. Exp Cell Res. 2015;339(2):261–9.PubMedView ArticleGoogle Scholar
  154. Indig FE, Diaz-Gonzalez F, Ginsberg MH. Analysis of the tetraspanin CD9-integrin αIIbβ3 (GPIIb-IIIa) complex in platelet membranes and transfected cells. Biochem J. 1997;327(Pt 1):291–8.PubMedPubMed CentralView ArticleGoogle Scholar
  155. Israels SJ, McMillan-Ward EM, Easton J, Robertson C, McNicol A. CD63 associates with the αIIbβ3 integrin-CD9 complex on the surface of activated platelets. Thromb Haemost. 2001;85(1):134–41.PubMedView ArticleGoogle Scholar
  156. Wright MD, Geary SM, Fitter S, Moseley GW, Lau LM, Sheng KC, et al. Characterization of mice lacking the tetraspanin superfamily member CD151. Mol Cell Biol. 2004;24(13):5978–88.PubMedPubMed CentralView ArticleGoogle Scholar
  157. Makkawi M, Moheimani F, Alserihi R, Howells D, Wright M, Ashman L, et al. A complementary role for tetraspanin superfamily member CD151 and ADP purinergic P2Y12 receptor in platelets. Thromb Haemost. 2015;114(5):1004–19.PubMedView ArticleGoogle Scholar
  158. Makkawi M, Howells D, Wright MD, Jackson DE. A complementary role for tetraspanin superfamily member TSSC6 and ADP purinergic P2Y12 receptor in platelets. Thromb Res. 2018;161:12–21.PubMedView ArticleGoogle Scholar
  159. Mangin PH, Kleitz L, Boucheix C, Gachet C, Lanza F. CD9 negatively regulates integrin αIIbβ3 activation and could thus prevent excessive platelet recruitment at sites of vascular injury. J Thromb Haemost. 2009;7(5):900–2.PubMedView ArticleGoogle Scholar
  160. Saller F, Burnier L, Schapira M, Angelillo-Scherrer A. Role of the growth arrest-specific gene 6 (gas6) product in thrombus stabilization. Blood Cells Mol Dis. 2006;36(3):373–8.PubMedView ArticleGoogle Scholar
  161. Angelillo-Scherrer A, Burnier L, Flores N, Savi P, DeMol M, Schaeffer P, et al. Role of Gas6 receptors in platelet signaling during thrombus stabilization and implications for antithrombotic therapy. J Clin Invest. 2005;115(2):237–46.PubMedPubMed CentralView ArticleGoogle Scholar
  162. Gould WR, Baxi SM, Schroeder R, Peng YW, Leadley RJ, Peterson JT, et al. Gas6 receptors Axl, Sky and Mer enhance platelet activation and regulate thrombotic responses. J Thromb Haemost. 2005;3(4):733–41.PubMedView ArticleGoogle Scholar
  163. Cosemans JM, Van Kruchten R, Olieslagers S, Schurgers LJ, Verheyen FK, Munnix IC, et al. Potentiating role of Gas6 and Tyro3, Axl and Mer (TAM) receptors in human and murine platelet activation and thrombus stabilization. J Thromb Haemost. 2010;8(8):1797–808.PubMedView ArticleGoogle Scholar
  164. Law LA, Graham DK, Di Paola J, Branchford BR. GAS6/TAM pathway signaling in hemostasis and thrombosis. Front Med (Lausanne). 2018;5:137.View ArticleGoogle Scholar
  165. Wannemacher KM, Zhu L, Jiang H, Fong KP, Stalker TJ, Lee D, et al. Diminished contact-dependent reinforcement of Syk activation underlies impaired thrombus growth in mice lacking Semaphorin 4D. Blood. 2010;116(25):5707–15.PubMedPubMed CentralView ArticleGoogle Scholar
  166. Nanda N, Andre P, Bao M, Clauser K, Deguzman F, Howie D, et al. Platelet aggregation induces platelet aggregate stability via SLAM family receptor signaling. Blood. 2005;106(9):3028–34.PubMedView ArticleGoogle Scholar
  167. Hofmann S, Braun A, Pozgaj R, Morowski M, Vogtle T, Nieswandt B. Mice lacking the SLAM family member CD84 display unaltered platelet function in hemostasis and thrombosis. PLoS One. 2014;9(12):e115306.PubMedPubMed CentralView ArticleGoogle Scholar
  168. Gong H, Shen B, Flevaris P, Chow C, Lam SC, Voyno-Yasenetskaya TA, et al. G protein subunit Gα13 binds to integrin αIIbβ3 and mediates integrin “outside-in” signaling. Science. 2010;327(5963):340–3.PubMedPubMed CentralView ArticleGoogle Scholar
  169. Moers A, Nieswandt B, Massberg S, Wettschureck N, Gruner S, Konrad I, et al. G13 is an essential mediator of platelet activation in hemostasis and thrombosis. Nat Med. 2003;9(11):1418–22.PubMedView ArticleGoogle Scholar
  170. Xiang B, Zhang G, Ye S, Zhang R, Huang C, Liu J, et al. Characterization of a novel integrin binding protein, VPS33B, which is important for platelet activation and in vivo thrombosis and hemostasis. Circulation. 2015;132(24):2334–44.PubMedPubMed CentralView ArticleGoogle Scholar
  171. Obergfell A, Judd BA, del Pozo MA, Schwartz MA, Koretzky GA, Shattil SJ. The molecular adapter SLP-76 relays signals from platelet integrin αIIbβ3 to the actin cytoskeleton. J Biol Chem. 2001;276(8):5916–23.PubMedView ArticleGoogle Scholar
  172. Leon C, Eckly A, Hechler B, Aleil B, Freund M, Ravanat C, et al. Megakaryocyte-restricted MYH9 inactivation dramatically affects hemostasis while preserving platelet aggregation and secretion. Blood. 2007;110(9):3183–91.PubMedView ArticleGoogle Scholar
  173. Deshmukh L, Gorbatyuk V, Vinogradova O. Integrin β3 phosphorylation dictates its complex with the Shc phosphotyrosine-binding (PTB) domain. J Biol Chem. 2010;285(45):34875–84.PubMedPubMed CentralView ArticleGoogle Scholar
  174. Law DA, Nannizzi-Alaimo L, Phillips DR. Outside-in integrin signal transduction. αIIbβ3-(GP IIb IIIa) tyrosine phosphorylation induced by platelet aggregation. J Biol Chem. 1996;271(18):10811–5.PubMedView ArticleGoogle Scholar
  175. Boylan B, Gao C, Rathore V, Gill JC, Newman DK, Newman PJ. Identification of FcγRIIa as the ITAM-bearing receptor mediating αIIbβ3 outside-in integrin signaling in human platelets. Blood. 2008;112(7):2780–6.PubMedPubMed CentralView ArticleGoogle Scholar
  176. Takizawa H, Nishimura S, Takayama N, Oda A, Nishikii H, Morita Y, et al. Lnk regulates integrin αIIbβ3 outside-in signaling in mouse platelets, leading to stabilization of thrombus development in vivo. J Clin Invest. 2010;120(1):179–90.PubMedView ArticleGoogle Scholar
  177. Xu Y, Ouyang X, Yan L, Zhang M, Hu Z, Gu J, et al. Sin1 (stress-activated protein kinase-interacting protein) regulates ischemia-induced microthrombosis through integrin αIIbβ3-mediated outside-in signaling and hypoxia responses in platelets. Arterioscler Thromb Vasc Biol. 2018;38(12):2793–805.Google Scholar
  178. Tsai HJ, Tseng CP. The adaptor protein Disabled-2: new insights into platelet biology and integrin signaling. Thromb J. 2016;14(Suppl 1):28.PubMedPubMed CentralView ArticleGoogle Scholar
  179. Tsai HJ, Huang CL, Chang YW, Huang DY, Lin CC, Cooper JA, et al. Disabled-2 is required for efficient hemostasis and platelet activation by thrombin in mice. Arterioscler Thromb Vasc Biol. 2014;34(11):2404–12.PubMedPubMed CentralView ArticleGoogle Scholar
  180. Shcherbina A, Cooley J, Lutskiy MI, Benarafa C, Gilbert GE, Remold-O’Donnell E. WASP plays a novel role in regulating platelet responses dependent on αIIbβ3 integrin outside-in signalling. Br J Haematol. 2010;148(3):416–27.PubMedView ArticleGoogle Scholar
  181. Shen B, Zhao X, O’Brien KA, Stojanovic-Terpo A, Delaney MK, Kim K, et al. A directional switch of integrin signalling and a new anti-thrombotic strategy. Nature. 2013;503(7474):131–5.PubMedPubMed CentralView ArticleGoogle Scholar
  182. Clements JL, Lee JR, Gross B, Yang B, Olson JD, Sandra A, et al. Fetal hemorrhage and platelet dysfunction in SLP-76-deficient mice. J Clin Invest. 1999;103(1):19–25.PubMedPubMed CentralView ArticleGoogle Scholar
  183. Judd BA, Myung PS, Leng L, Obergfell A, Pear WS, Shattil SJ, et al. Hematopoietic reconstitution of SLP-76 corrects hemostasis and platelet signaling through αIIbβ3 and collagen receptors. Proc Natl Acad Sci U S A. 2000;97(22):12056–61.PubMedPubMed CentralView ArticleGoogle Scholar
  184. Zhang H, Berg JS, Li Z, Wang Y, Lang P, Sousa AD, et al. Myosin-X provides a motor-based link between integrins and the cytoskeleton. Nat Cell Biol. 2004;6(6):523–31.PubMedView ArticleGoogle Scholar
  185. Donner L, Gremer L, Ziehm T, Gertzen CGW, Gohlke H, Willbold D, et al. Relevance of N-terminal residues for amyloid-β binding to platelet integrin αIIbβ3, integrin outside-in signaling and amyloid-β fibril formation. Cell Signal. 2018;50:121–30.PubMedView ArticleGoogle Scholar
  186. Verhaar R, Dekkers DW, De Cuyper IM, Ginsberg MH, de Korte D, Verhoeven AJ. UV-C irradiation disrupts platelet surface disulfide bonds and activates the platelet integrin αIIbβ3. Blood. 2008;112(13):4935–9.PubMedPubMed CentralView ArticleGoogle Scholar
  187. Ghuman H, Shepherd-Roberts A, Watson S, Zuidscherwoude M, Watson SP, Voelz K. Mucor circinelloides induces platelet aggregation through integrin αIIbβ3 and FcγRIIA. Platelets. 2018. https://doi.org/10.1080/09537104.2017.1420152.
  188. Gao C, Boylan B, Fang J, Wilcox DA, Newman DK, Newman PJ. Heparin promotes platelet responsiveness by potentiating αIIbβ3-mediated outside-in signaling. Blood. 2011;117(18):4946–52.PubMedPubMed CentralView ArticleGoogle Scholar
  189. Kiouptsi K, Gambaryan S, Walter E, Walter U, Jurk K, Reinhardt C. Hypoxia impairs agonist-induced integrin αIIbβ3 activation and platelet aggregation. Sci Rep. 2017;7(1):7621.PubMedPubMed CentralView ArticleGoogle Scholar
  190. Unsworth AJ, Kriek N, Bye AP, Naran K, Sage T, Flora GD, et al. PPARγ agonists negatively regulate αIIbβ3 integrin outside-in signaling and platelet function through up-regulation of protein kinase A activity. J Thromb Haemost. 2017;15(2):356–69.PubMedPubMed CentralView ArticleGoogle Scholar
  191. Tseng WL, Huang CL, Chong KY, Liao CH, Stern A, Cheng JC, et al. Reelin is a platelet protein and functions as a positive regulator of platelet spreading on fibrinogen. Cell Mol Life Sci. 2010;67(4):641–53.PubMedView ArticleGoogle Scholar
  192. Gowert NS, Kruger I, Klier M, Donner L, Kipkeew F, Gliem M, et al. Loss of Reelin protects mice against arterial thrombosis by impairing integrin activation and thrombus formation under high shear conditions. Cell Signal. 2017;40:210–21.PubMedView ArticleGoogle Scholar
  193. Zhao Z, Wu Y, Zhou J, Chen F, Yang A, Essex DW. The transmembrane protein disulfide isomerase TMX1 negatively regulates platelet responses. Blood. 2019;133(3):246–51.PubMedView ArticleGoogle Scholar
  194. Arias-Salgado EG, Lizano S, Shattil SJ, Ginsberg MH. Specification of the direction of adhesive signaling by the integrin β cytoplasmic domain. J Biol Chem. 2005;280(33):29699–707.PubMedView ArticleGoogle Scholar
  195. Arias-Salgado EG, Lizano S, Sarkar S, Brugge JS, Ginsberg MH, Shattil SJ. Src kinase activation by direct interaction with the integrin β cytoplasmic domain. Proc Natl Acad Sci U S A. 2003;100(23):13298–302.PubMedPubMed CentralView ArticleGoogle Scholar
  196. Huang J, Shi X, Xi W, Liu P, Long Z, Xi X. Evaluation of targeting c-Src by the RGT-containing peptide as a novel antithrombotic strategy. J Hematol Oncol. 2015;8:62.PubMedPubMed CentralView ArticleGoogle Scholar
  197. Su X, Mi J, Yan J, Flevaris P, Lu Y, Liu H, et al. RGT, a synthetic peptide corresponding to the integrin β3 cytoplasmic C-terminal sequence, selectively inhibits outside-in signaling in human platelets by disrupting the interaction of integrin αIIbβ3 with Src kinase. Blood. 2008;112(3):592–602.PubMedPubMed CentralView ArticleGoogle Scholar
  198. Ablooglu AJ, Kang J, Petrich BG, Ginsberg MH, Shattil SJ. Antithrombotic effects of targeting αIIbβ3 signaling in platelets. Blood. 2009;113(15):3585–92.PubMedPubMed CentralView ArticleGoogle Scholar
  199. Arias-Salgado EG, Haj F, Dubois C, Moran B, Kasirer-Friede A, Furie BC, et al. PTP-1B is an essential positive regulator of platelet integrin signaling. J Cell Biol. 2005;170(5):837–45.PubMedPubMed CentralView ArticleGoogle Scholar
  200. Obergfell A, Eto K, Mocsai A, Buensuceso C, Moores SL, Brugge JS, et al. Coordinate interactions of Csk, Src, and Syk kinases with αIIbβ3 initiate integrin signaling to the cytoskeleton. J Cell Biol. 2002;157(2):265–75.PubMedPubMed CentralView ArticleGoogle Scholar
  201. Bustelo XR. Regulatory and signaling properties of the Vav family. Mol Cell Biol. 2000;20(5):1461–77.PubMedPubMed CentralView ArticleGoogle Scholar
  202. Pearce AC, McCarty OJ, Calaminus SD, Vigorito E, Turner M, Watson SP. Vav family proteins are required for optimal regulation of PLCγ2 by integrin αIIbβ3. Biochem J. 2007;401(3):753–61.PubMedPubMed CentralView ArticleGoogle Scholar
  203. Law DA, Nannizzi-Alaimo L, Ministri K, Hughes PE, Forsyth J, Turner M, et al. Genetic and pharmacological analyses of Syk function in αIIbβ3 signaling in platelets. Blood. 1999;93(8):2645–52.PubMedGoogle Scholar
  204. Poole A, Gibbins JM, Turner M, van Vugt MJ, van de Winkel JG, Saito T, et al. The Fc receptor γ-chain and the tyrosine kinase Syk are essential for activation of mouse platelets by collagen. EMBO J. 1997;16(9):2333–41.PubMedPubMed CentralView ArticleGoogle Scholar
  205. Clark EA, Shattil SJ, Brugge JS. Regulation of protein tyrosine kinases in platelets. Trends Biochem Sci. 1994;19(11):464–9.PubMedView ArticleGoogle Scholar
  206. Beck S, Leitges M, Stegner D. Protein kinase Cι/λ is dispensable for platelet function in thrombosis and hemostasis in mice. Cell Signal. 2017;38:223–9.PubMedView ArticleGoogle Scholar
  207. Yoshioka A, Shirakawa R, Nishioka H, Tabuchi A, Higashi T, Ozaki H, et al. Identification of protein kinase Cα as an essential, but not sufficient, cytosolic factor for Ca2+-induced α- and dense-core granule secretion in platelets. J Biol Chem. 2001;276(42):39379–85.PubMedView ArticleGoogle Scholar
  208. Tabuchi A, Yoshioka A, Higashi T, Shirakawa R, Nishioka H, Kita T, et al. Direct demonstration of involvement of protein kinase Cα in the Ca2+-induced platelet aggregation. J Biol Chem. 2003;278(29):26374–9.PubMedView ArticleGoogle Scholar
  209. Buensuceso CS, Obergfell A, Soriani A, Eto K, Kiosses WB, Arias-Salgado EG, et al. Regulation of outside-in signaling in platelets by integrin-associated protein kinase Cβ. J Biol Chem. 2005;280(1):644–53.PubMedView ArticleGoogle Scholar
  210. Pula G, Schuh K, Nakayama K, Nakayama KI, Walter U, Poole AW. PKCδ regulates collagen-induced platelet aggregation through inhibition of VASP-mediated filopodia formation. Blood. 2006;108(13):4035–44.PubMedView ArticleGoogle Scholar
  211. Chari R, Getz T, Nagy B Jr, Bhavaraju K, Mao Y, Bynagari YS, et al. Protein kinase Cδ differentially regulates platelet functional responses. Arterioscler Thromb Vasc Biol. 2009;29(5):699–705.PubMedPubMed CentralView ArticleGoogle Scholar
  212. Soriani A, Moran B, de Virgilio M, Kawakami T, Altman A, Lowell C, et al. A role for PKCθ in outside-in αIIbβ3 signaling. J Thromb Haemost. 2006;4(3):648–55.PubMedView ArticleGoogle Scholar
  213. Hall KJ, Harper MT, Gilio K, Cosemans JM, Heemskerk JW, Poole AW. Genetic analysis of the role of protein kinase Cθ in platelet function and thrombus formation. PLoS One. 2008;3(9):e3277.PubMedPubMed CentralView ArticleGoogle Scholar
  214. Maxwell MJ, Yuan Y, Anderson KE, Hibbs ML, Salem HH, Jackson SP. SHIP1 and Lyn kinase negatively regulate integrin αIIbβ3 signaling in platelets. J Biol Chem. 2004;279(31):32196–204.PubMedView ArticleGoogle Scholar
  215. Battram AM, Durrant TN, Agbani EO, Heesom KJ, Paul DS, Piatt R, et al. The phosphatidylinositol 3,4,5-trisphosphate (PI (3,4,5) P3) binder Rasa3 regulates phosphoinositide 3-kinase (PI3K)-dependent integrin αIIbβ3 outside-in signaling. J Biol Chem. 2017;292(5):1691–704.PubMedView ArticleGoogle Scholar
  216. Sun DS, Lo SJ, Lin CH, Yu MS, Huang CY, Chen YF, et al. Calcium oscillation and phosphatidylinositol 3-kinase positively regulate integrin αIIbβ3-mediated outside-in signaling. J Biomed Sci. 2005;12(2):321–33.PubMedView ArticleGoogle Scholar
  217. Lian L, Wang Y, Draznin J, Eslin D, Bennett JS, Poncz M, et al. The relative role of PLCβ and PI3Kγ in platelet activation. Blood. 2005;106(1):110–7.PubMedPubMed CentralView ArticleGoogle Scholar
  218. Cosemans JM, Munnix IC, Wetzker R, Heller R, Jackson SP, Heemskerk JW. Continuous signaling via PI3K isoforms β and γ is required for platelet ADP receptor function in dynamic thrombus stabilization. Blood. 2006;108(9):3045–52.PubMedView ArticleGoogle Scholar
  219. Laurent PA, Hechler B, Solinhac R, Ragab A, Cabou C, Anquetil T, et al. Impact of PI3Kα (phosphoinositide 3-kinase α) inhibition on hemostasis and thrombosis. Arterioscler Thromb Vasc Biol. 2018;38(9):2041–53.PubMedView ArticleGoogle Scholar
  220. Buitrago L, Langdon WY, Sanjay A, Kunapuli SP. Tyrosine phosphorylated c-Cbl regulates platelet functional responses mediated by outside-in signaling. Blood. 2011;118(20):5631–40.PubMedPubMed CentralView ArticleGoogle Scholar
  221. Cipolla L, Consonni A, Guidetti G, Canobbio I, Okigaki M, Falasca M, et al. The proline-rich tyrosine kinase Pyk2 regulates platelet integrin αIIbβ3 outside-in signaling. J Thromb Haemost. 2013;11(2):345–56.PubMedView ArticleGoogle Scholar
  222. Canobbio I, Cipolla L, Consonni A, Momi S, Guidetti G, Oliviero B, et al. Impaired thrombin-induced platelet activation and thrombus formation in mice lacking the Ca (2+)-dependent tyrosine kinase Pyk2. Blood. 2013;121(4):648–57.PubMedView ArticleGoogle Scholar
  223. Laurent PA, Severin S, Hechler B, Vanhaesebroeck B, Payrastre B, Gratacap MP. Platelet PI3Kβ and GSK3 regulate thrombus stability at a high shear rate. Blood. 2015;125(5):881–8.PubMedView ArticleGoogle Scholar
  224. Prevost N, Mitsios JV, Kato H, Burke JE, Dennis EA, Shimizu T, et al. Group IVA cytosolic phospholipase A2 (cPLA2α) and integrin αIIbβ3 reinforce each other’s functions during αIIbβ3 signaling in platelets. Blood. 2009;113(2):447–57.PubMedPubMed CentralView ArticleGoogle Scholar
  225. Wong DA, Kita Y, Uozumi N, Shimizu T. Discrete role for cytosolic phospholipase A (2) α in platelets: studies using single and double mutant mice of cytosolic and group IIA secretory phospholipase A (2). J Exp Med. 2002;196(3):349–57.PubMedPubMed CentralView ArticleGoogle Scholar
  226. Khatlani T, Pradhan S, Da Q, Shaw T, Buchman VL, Cruz MA, et al. A novel interaction of the catalytic subunit of protein phosphatase 2A with the adaptor protein CIN85 suppresses phosphatase activity and facilitates platelet outside-in αIIbβ3 integrin signaling. J Biol Chem. 2016;291(33):17360–8.PubMedPubMed CentralView ArticleGoogle Scholar
  227. Pleines I, Hagedorn I, Gupta S, May F, Chakarova L, van Hengel J, et al. Megakaryocyte-specific RhoA deficiency causes macrothrombocytopenia and defective platelet activation in hemostasis and thrombosis. Blood. 2012;119(4):1054–63.PubMedView ArticleGoogle Scholar
  228. Pleines I, Elvers M, Strehl A, Pozgajova M, Varga-Szabo D, May F, et al. Rac1 is essential for phospholipase C-γ2 activation in platelets. Pflugers Arch. 2009;457(5):1173–85.PubMedView ArticleGoogle Scholar
  229. Akbar H, Shang X, Perveen R, Berryman M, Funk K, Johnson JF, et al. Gene targeting implicates Cdc42 GTPase in GPVI and non-GPVI mediated platelet filopodia formation, secretion and aggregation. PLoS One. 2011;6(7):e22117.PubMedPubMed CentralView ArticleGoogle Scholar
  230. Giordano A, Musumeci G, D’Angelillo A, Rossini R, Zoccai GB, Messina S, et al. Effects of glycoprotein IIb/IIIa antagonists: anti platelet aggregation and beyond. Curr Drug Metab. 2016;17(2):194–203.PubMedView ArticleGoogle Scholar
  231. Schwarz M, Nordt T, Bode C, Peter K. The GP IIb/IIIa inhibitor abciximab (c7E3) inhibits the binding of various ligands to the leukocyte integrin Mac-1 (CD11b/CD18, alphaMbeta2). Thromb Res. 2002;107(3–4):121–8.PubMedView ArticleGoogle Scholar
  232. Scarborough RM, Naughton MA, Teng W, Rose JW, Phillips DR, Nannizzi L, et al. Design of potent and specific integrin antagonists. Peptide antagonists with high specificity for glycoprotein IIb-IIIa. J Biol Chem. 1993;268(2):1066–73.PubMedGoogle Scholar
  233. Topol EJ, Califf RM, Weisman HF, Ellis SG, Tcheng JE, Worley S, et al. Randomised trial of coronary intervention with antibody against platelet IIb/IIIa integrin for reduction of clinical restenosis: results at six months. The EPIC Investigators Lancet. 1994;343(8902):881–6.PubMedView ArticleGoogle Scholar
  234. Stoffer K, Shah S. Abciximab. StatPearls, Vol. Treasure Island (FL); 2018.Google Scholar
  235. De Luca G, Savonitto S, van’t Hof AW, Suryapranata H. Platelet GP IIb-IIIa receptor antagonists in primary angioplasty: back to the future. Drugs. 2015;75(11):1229–53.PubMedView ArticleGoogle Scholar
  236. Cannon CP, McCabe CH, Wilcox RG, Langer A, Caspi A, Berink P, et al. Oral glycoprotein IIb/IIIa inhibition with orbofiban in patients with unstable coronary syndromes (OPUS-TIMI 16) trial. Circulation. 2000;102(2):149–56.PubMedView ArticleGoogle Scholar
  237. Fan P, Gao Y, Zheng M, Xu T, Schoenhagen P, Jin Z. Recent progress and market analysis of anticoagulant drugs. J Thorac Dis. 2018;10(3):2011–25.PubMedPubMed CentralView ArticleGoogle Scholar
  238. Goodman SL, Picard M. Integrins as therapeutic targets. Trends Pharmacol Sci. 2012;33(7):405–12.PubMedView ArticleGoogle Scholar
  239. Xie Z, Cao C, Feng S, Huang J, Li Z. Progress in the research of GPIIb/IIIa antagonists. Future Med Chem. 2015;7(9):1149–71.PubMedView ArticleGoogle Scholar
  240. Jamasbi J, Ayabe K, Goto S, Nieswandt B, Peter K, Siess W. Platelet receptors as therapeutic targets: past, present and future. Thromb Haemost. 2017;117(7):1249–57.PubMedView ArticleGoogle Scholar
  241. Estevez B, Shen B, Du X. Targeting integrin and integrin signaling in treating thrombosis. Arterioscler Thromb Vasc Biol. 2015;35(1):24–9.PubMedView ArticleGoogle Scholar
  242. Bassler N, Loeffler C, Mangin P, Yuan Y, Schwarz M, Hagemeyer CE, et al. A mechanistic model for paradoxical platelet activation by ligand-mimetic αIIbβ3 (GPIIb/IIIa) antagonists. Arterioscler Thromb Vasc Biol. 2007;27(3):e9–15.Google Scholar
  243. Wang X, Palasubramaniam J, Gkanatsas Y, Hohmann JD, Westein E, Kanojia R, et al. Towards effective and safe thrombolysis and thromboprophylaxis: preclinical testing of a novel antibody-targeted recombinant plasminogen activator directed against activated platelets. Circ Res. 2014;114(7):1083–93.PubMedView ArticleGoogle Scholar
  244. Fuentes RE, Zaitsev S, Ahn HS, Hayes V, Kowalska MA, Lambert MP, et al. A chimeric platelet-targeted urokinase prodrug selectively blocks new thrombus formation. J Clin Invest. 2016;126(2):483–94.PubMedView ArticleGoogle Scholar
  245. Hohmann JD, Wang X, Krajewski S, Selan C, Haller CA, Straub A, et al. Delayed targeting of CD39 to activated platelet GPIIb/IIIa via a single-chain antibody: breaking the link between antithrombotic potency and bleeding? Blood. 2013;121(16):3067–75.PubMedPubMed CentralView ArticleGoogle Scholar
  246. Liu TD, Ren SH, Ding X, Xie ZL, Kong Y. A short half-life αIIbβ3 antagonist ANTP266 reduces thrombus formation. Int J Mol Sci. 2018;19(8):2306.Google Scholar
  247. Li J, Vootukuri S, Shang Y, Negri A, Jiang JK, Nedelman M, et al. RUC-4: a novel αIIbβ3 antagonist for prehospital therapy of myocardial infarction. Arterioscler Thromb Vasc Biol. 2014;34(10):2321–9.Google Scholar
  248. Law DA, DeGuzman FR, Heiser P, Ministri-Madrid K, Killeen N, Phillips DR. Integrin cytoplasmic tyrosine motif is required for outside-in αIIbβ3 signalling and platelet function. Nature. 1999;401(6755):808–11.Google Scholar
  249. Schroder J, Lullmann-Rauch R, Himmerkus N, Pleines I, Nieswandt B, Orinska Z, et al. Deficiency of the tetraspanin CD63 associated with kidney pathology but normal lysosomal function. Mol Cell Biol. 2009;29(4):1083–94.PubMedView ArticleGoogle Scholar
  250. Senis YA, Tomlinson MG, Ellison S, Mazharian A, Lim J, Zhao Y, et al. The tyrosine phosphatase CD148 is an essential positive regulator of platelet activation and thrombosis. Blood. 2009;113(20):4942–54.PubMedPubMed CentralView ArticleGoogle Scholar
  251. Wang L, Wu Y, Zhou J, Ahmad SS, Mutus B, Garbi N, et al. Platelet-derived ERp57 mediates platelet incorporation into a growing thrombus by regulation of the αIIbβ3 integrin. Blood. 2013;122(22):3642–50.PubMedPubMed CentralView ArticleGoogle Scholar
  252. Fan X, Wang C, Shi P, Gao W, Gu J, Geng Y, et al. Platelet MEKK3 regulates arterial thrombosis and myocardial infarct expansion in mice. Blood Adv. 2018;2(12):1439–48.PubMedPubMed CentralView ArticleGoogle Scholar
  253. Chen X, Fan X, Tan J, Shi P, Wang X, Wang J, et al. Palladin is involved in platelet activation and arterial thrombosis. Thromb Res. 2017;149:1–8.PubMedView ArticleGoogle Scholar
  254. Chen X, Zhang Y, Wang Y, Li D, Zhang L, Wang K, et al. PDK1 regulates platelet activation and arterial thrombosis. Blood. 2013;121(18):3718–26.PubMedView ArticleGoogle Scholar
  255. Weng Z, Li D, Zhang L, Chen J, Ruan C, Chen G, et al. PTEN regulates collagen-induced platelet activation. Blood. 2010;116(14):2579–81.PubMedView ArticleGoogle Scholar
  256. McCarty OJ, Larson MK, Auger JM, Kalia N, Atkinson BT, Pearce AC, et al. Rac1 is essential for platelet lamellipodia formation and aggregate stability under flow. J Biol Chem. 2005;280(47):39474–84.PubMedPubMed CentralView ArticleGoogle Scholar
  257. Sladojevic N, Oh GT, Kim HH, Beaulieu LM, Falet H, Kaminski K, et al. Decreased thromboembolic stroke but not atherosclerosis or vascular remodelling in mice with ROCK2-deficient platelets. Cardiovasc Res. 2017;113(11):1307–17.PubMedPubMed CentralView ArticleGoogle Scholar
  258. Graff J, Klinkhardt U, Westrup D, Kirchmaier CM, Breddin HK, Harder S. Pharmacodynamic characterization of the interaction between the glycoprotein IIb/IIIa inhibitor YM337 and unfractionated heparin and aspirin in humans. Br J Clin Pharmacol. 2003;56(3):321–6.PubMedPubMed CentralView ArticleGoogle Scholar
  259. Greenberg HE, Wissel P, Barrett J, Barchowsky A, Gould R, Farrell D, et al. Antiplatelet effects of MK-852, a platelet fibrinogen receptor antagonist, in healthy volunteers. J Clin Pharmacol. 2000;40(5):496–507.PubMedView ArticleGoogle Scholar
  260. Collen D, Lu HR, Stassen JM, Vreys I, Yasuda T, Bunting S, et al. Antithrombotic effects and bleeding time prolongation with synthetic platelet GPIIb/IIIa inhibitors in animal models of platelet-mediated thrombosis. Thromb Haemost. 1994;71(1):95–102.PubMedView ArticleGoogle Scholar
  261. Michaelis W, Turlapaty P, Gray J, Fiske WD, Faulkner E, Kornhauser D, et al. Pharmacodynamics and pharmacokinetics of DMP 728, a platelet GPIIb/IIIa antagonist, in healthy subjects. Clin Pharmacol Ther. 1998;63(3):384–92.PubMedView ArticleGoogle Scholar
  262. Hartman GD, Egbertson MS, Halczenko W, Laswell WL, Duggan ME, Smith RL, et al. Non-peptide fibrinogen receptor antagonists. 1. Discovery and design of exosite inhibitors. J Med Chem. 1992;35(24):4640–2.PubMedView ArticleGoogle Scholar
  263. Starnes HB, Patel AA, Stouffer GA. Optimal use of platelet glycoprotein IIb/IIIa receptor antagonists in patients undergoing percutaneous coronary interventions. Drugs. 2011;71(15):2009–30.PubMedView ArticleGoogle Scholar
  264. Storey RF, Wilcox RG, Heptinstall S. Differential effects of glycoprotein IIb/IIIa antagonists on platelet microaggregate and macroaggregate formation and effect of anticoagulant on antagonist potency. Implications for assay methodology and comparison of different antagonists. Circulation. 1998;98(16):1616–21.PubMedView ArticleGoogle Scholar
  265. Brugts JJ, Mercado N, Hu S, Guarneri M, Price M, Schatz R, et al. Relation of periprocedural bleeding complications and long-term outcome in patients undergoing percutaneous coronary revascularization (from the Evaluation of Oral Xemilofiban in Controlling Thrombotic Events [EXCITE] Trial). Am J Cardiol. 2009;103(7):917–22.PubMedView ArticleGoogle Scholar
  266. Smith EE, Cannon CP, Murphy S, Feske SK, Schwamm LH. Risk factors for stroke after acute coronary syndromes in the orbofiban in patients with unstable coronary syndromes--thrombolysis in myocardial infarction (OPUS-TIMI) 16 study. Am Heart J. 2006;151(2):338–44.PubMedView ArticleGoogle Scholar
  267. Wong CK, Newby LK, Bhapker MV, Aylward PE, Pfisterer M, Alexander KP, et al. Use of evidence-based medicine for acute coronary syndromes in the elderly and very elderly: insights from the Sibrafiban vs aspirin to yield maximum protection from ischemic heart events postacute cOroNary sYndromes trials. Am Heart J. 2007;154(2):313–21.PubMedView ArticleGoogle Scholar
  268. Topol EJ, Easton D, Harrington RA, Amarenco P, Califf RM, Graffagnino C, et al. Randomized, double-blind, placebo-controlled, international trial of the oral IIb/IIIa antagonist lotrafiban in coronary and cerebrovascular disease. Circulation. 2003;108(4):399–406.PubMedView ArticleGoogle Scholar
  269. Murphy J, Wright RS, Gussak I, Williams B, Daly RN, Cain VA, et al. The use of roxifiban (DMP754), a novel oral platelet glycoprotein IIb/IIIa receptor inhibitor, in patients with stable coronary artery disease. Am J Cardiovasc Drugs. 2003;3(2):101–12.PubMedView ArticleGoogle Scholar
  270. Damiano BP, Mitchell JA, Giardino E, Corcoran T, Haertlein BJ, de Garavilla L, et al. Antiplatelet and antithrombotic activity of RWJ-53308, a novel orally active glycoprotein IIb/IIIa antagonist. Thromb Res. 2001;104(2):113–26.PubMedView ArticleGoogle Scholar
  271. Savi P, Badorc A, Lale A, Bordes MF, Bornia J, Labouret C, et al. SR 121787, a new orally active fibrinogen receptor antagonist. Thromb Haemost. 1998;80(3):469–76.PubMedView ArticleGoogle Scholar
  272. Giugliano RP, McCabe CH, Sequeira RF, Frey MJ, Henry TD, Piana RN, et al. First report of an intravenous and oral glycoprotein IIb/IIIa inhibitor (RPR 109891) in patients with recent acute coronary syndromes: results of the TIMI 15A and 15B trials. Am Heart J. 2000;140(1):81–93.PubMedView ArticleGoogle Scholar
  273. Zhu J, Choi WS, McCoy JG, Negri A, Zhu J, Naini S, et al. Structure-guided design of a high-affinity platelet integrin αIIbβ3 receptor antagonist that disrupts Mg (2)(+) binding to the MIDAS. Sci Transl Med. 2012;4(125):125ra32.Google Scholar
  274. Polishchuk PG, Samoylenko GV, Khristova TM, Krysko OL, Kabanova TA, Kabanov VM, et al. Design, virtual screening, and synthesis of antagonists of αIIbβ3 as antiplatelet agents. J Med Chem. 2015;58(19):7681–94.Google Scholar
  275. Ziegler M, Hohmann JD, Searle AK, Abraham MK, Nandurkar HH, Wang X, et al. A single-chain antibody-CD39 fusion protein targeting activated platelets protects from cardiac ischaemia/reperfusion injury. Eur Heart J. 2018;39(2):111–6.PubMedGoogle Scholar

Copyright

© The Author(s). 2019

Advertisement