Recent progress on vascular endothelial growth factor receptor inhibitors with dual targeting capabilities for tumor therapy

Table 1 Unique characteristics of the VEGFR family

Receptor	VEGFR1	VEGFR2	VEGFR3
Protein size	180–185 kDa	210–230 kDa	195 kDa
Ligands	VEGF-A, VEGF-B and PIGF	VEGF-A, VEGF-C and VEGF-D	VEGF-C and VEGF-D
Functions	A negative regulator of angiogenesis, vasculogenesis and monocyte/macrophage motility	Vasculogenesis, angiogenesis, vascular permeability and endothelial cell motility and survival	Vascular and lymphatic development and maintenance
Full length	1338	1356	1363
Signal peptide	1–26	1–19	1–24
Receptor chain	27–1338	20–1356	25–1363
ECD	27–758	20–764	25–775
IgD1	32–123	46–110	30–127
IgD2	151–214	141–207	151–213
IgD3	230–327	224–320	219–326
IgD4	335–421	328–414	331–415
IgD5	428–553	421–548	422–552
IgD6	556–654	551–660	555–671
IgD7	661–747	667–753	678–764
TM	759–780	765–785	776–796
Cytoplasmic domain	781–1338	786–1356	797–1363

ISSN: 1756-8722