FGF Family

Fibroblast growth factors (FGFs) are a family of structurally related polypeptide growth factors that have diverse roles in regulating cell proliferation, migration, differentiation, and apoptosis. The FGFs exert multiple functions by binding to FGF receptors (FGFRs) with heparin/heparan sulphate as a cofactor. Activated FGFRs mediate signaling by recruiting specific molecules that bind to phosphorylated tyrosine at the cytosolic part of the receptor, triggering a number of signaling pathways, such as RAS-MAPK, PI3K-AKT, PLCγ, and STAT signaling pathways, and leading to specific cellular responses. The mammalian Fgf family contains 22 genes, 18 of which encode proteins (FGF1-FGF10 and FGF16-FGF23) known to signal through four highly conserved transmembrane tyrosine kinase receptors (FGFR1, FGFR2, FGFR3, and FGFR4). The FGF homologous factors (FGF11, FGF12, FGF13, and FGF14) have high sequence identity with the FGF family but do not activate FGFRs and are therefore not generally considered members of the FGF family. FGFs are highly conserved in both gene structure and amino-acid sequence between vertebrate species.