Alias: FGF-1, acidic Fibroblast Growth Factor
FGF-1 is a member of a highly conserved family of heparin-binding proteins. Members of the FGF family share four common tyrosine kinase receptors, FGFR 1-4, and require the binding of a second surface protein, the ubiquitously expressed heparin sulfate proteoglycans, in order to fully activate these receptors. FGF acidic and FGF basic share similar biological functions and expression of both has been detected in several cell types, including fibroblasts, macrophages, endothelial cells, epithelial cells, and neurons. Both are unique from other members of the family in their lack of a signal sequence peptide necessary for the secretory pathway, indicating that secretion occurs via an alternate route. The secreted form of FGF-1 is a homodimer that is cleaved into its active form following release from the cell. FGF family members affect the proliferation, differentiation, mobility, and survival of several cell types, including fibroblasts, osteoblasts, smooth muscle cells, and neuroblasts. They are particularly important in embryonic development as triggers of neurogenesis, angiogenesis, and neovascularization. Both FGF acidic and FGF basic remain active during adulthood and play a role in bone formation and tissue repair. FGF family members are also implicated in many types of cancer and may contribute to tumor vascularization.