Fig. 3

Reprogramming of amino acid metabolism in the innate immune system. In the innate immune system, various amino acids affect innate immune cell functions. The same amino acids may play different role in the homeostasis/inflammation microenvironment and tumor microenvironment. The arrow line represents activation and the line with a bar at the end represents inhibition. 3-HAA 3-hydroxyanthranilic acid; AHR Aryl hydrocarbon receptor; Arg Arginine; Arg1/2 Arginase-1/2; BCAA Branched-chain amino acids; BCAT1 branched-chain aminotransferases 1; BH4 Tetrahydrobiopterin; BTK Bruton’s tyrosine kinase; C3 Complement 3; CTLA4 Cytotoxic T-lymphocyte associated protein 4; Cys Cystine; GCN2 General control nonderepressible 2; GCN2 General control nonderepressible 2; Gln Glutamine; Glu Glutamate; GSH Glutathione; HIF Hypoxia inducible factor; IDO Indoleamine 2,3-dioxygenase; IL Interleukin; iNOS Inducible isoform of NO synthase; KMO Kynurenine 3-monooxygenase; Kyn Kynurenine; KYNU 2-amino-4-[3-hydroxyphenyl]-4-hydroxybutanoic acid; Leu Leucine; LPS Lipopolysaccharide; SLC Solute carrier; STAT3 Signal transducer and activator of transcription 3; TAM Tumor-associated macrophages; TGF Transforming growth factor; Trp Tryptophan; Tα1 Thymosin α1