Fig. 1
From: Fibroblast growth factor signaling in axons: from development to disease
Fibroblast growth factor (FGF) phylogeny and receptor structure. A The FGFs subfamilies. The 22 FGF ligands are divided into 7 subfamilies according to their cofactors, binding specificity, sequence similarities and evolutionary relationships. B Schematic representation of the FGF-FGFR complex. This complex is composed of two receptor dimers and two FGFs. FGFRs (blue) are transmembrane proteins whose extracellular domain contains three immunoglobulin-like domains (IgI-IgIII) and an acidic box domain (yellow). Following a transmembrane α-helix, the intracellular domain is composed by a split tyrosine kinase domain (orange). The binding site for FGFs (green) comprises the region between the C-terminal portion of IgII and the N-terminal portion of IgIII. All FGFs include a heparan sulfate proteoglycan (HSPG) binding domain and the majority present a N-terminal signal peptide