FGF domain, beta-trefoil fold, found in fibroblast growth factor 6 (FGF6) and similar proteins
FGF6, also called heparin secretory-transforming protein 2 (HST-2), or HSTF-2, or heparin-binding growth factor 6 (HBGF6), plays an important role in the regulation of cell proliferation, cell differentiation, angiogenesis, and myogenesis, and is required for normal muscle regeneration. FGF6 interacts with fibroblast growth factor receptors, FGFR1, FGFR2, and FGFR4. Affinity between fibroblast growth factors (FGFs) and their receptors is increased by heparan sulfate glycosaminoglycans that function as coreceptors. FGF6 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.