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.
Fig 6. Fibroblast Growth Factor (FGF) Signalling