Fibroblast growth factors (FGFs) are small polypeptide growth factors, all of whom share in common certain structural characteristics. FGFs that signal through FGF receptors (FGFRs) regulate fundamental developmental pathways, controlling events such as mesoderm patterning in the early embryo through to the development of multiple organ systems. FGF signalling extends to many physiological roles in the adult organism, including the regulation of angiogenesis and wound repair.
Fibroblast Growth Factors (FGFs) possess high affinity for heparan sulfate proteoglycans (HPSGs) and can interact with heparin-like glycosa-minoglycans (HLGAGs) of the extracellular matrix (ECM). When Fibroblast Growth Factors (FGFs) binding with FGFRs in a FGF:FGFR:HPSG ternary complex form, dimerization of FGFRs occurs, which causes the receptors to be phosphorylated at the intracellular tyrosine kinase domain and carboxy-terminal tail.
Subsequently, the phosphorylated tyrosine recruits specific molecules, which interact with SH2 (Src homology-2) or PTB (phosphotyrosine binding) domains of adaptors docking proteins or signaling enzymes, forming signaling complexes. Then, a cascade of phosphorylation events occurs at the recruited complexes and induces a number of signaling pathways, such as the RAS/MAP kinase pathway, PI3 kinase/AKT pathway, and PLCγ pathway, resulting in specific cellular responses (Figure 1).
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