FGF domain, beta-trefoil fold, found in fibroblast growth factor 5 (FGF5) and similar proteins
FGF5, also called heparin-binding growth factor 5 (HBGF5), or Smag-82, plays an important role in the regulation of cell proliferation and cell differentiation. It is required for normal regulation of the hair growth cycle. It functions as an inhibitor of hair elongation by promoting progression from anagen, the growth phase of the hair follicle, into catagen the apoptosis-induced regression phase. FGF5 interacts with fibroblast growth factor receptors, FGFR1 and FGFR2. Affinity between FGFs and their receptors is increased by heparan sulfate glycosaminoglycans that function as coreceptors. FGF-5 contains a FGF domain with beta-trefoil fold, which is characterized by 12 beta strands folded into three similar trefoil subdomains (alpha, beta, and gamma) associated to give an overall structure with pseudo-3-fold symmetry.
Jiyao W et al.(2023). "The conserved domain database in 2023.",