FGF-BP

Fibroblast growth factor binding protein (FGF-BP), also known as HBp17, is a secreted glycoprotein that increases the bioavailability of FGFs. Mature FGFBP is a 34 kDa, 211 amino acid (aa) O-glycosylated protein with five conserved intrachain disulfide bonds. FGFBP contains a heparin-binding domain (aa 110-143) and a distinct FGF-binding region (aa 193-243) . Mature human FGF-BP shares 59% and 54% aa sequence identity with mouse and rat FGF-BP, respectively. FGF-BP is expressed throughout development and in adult squamous epithelium. It is upregulated in injured skin, renal tubular epithelium, and spinal nerves as well as in carcinomas of the skin, colon, and pancreas. FGF-BP binds FGF1, 2, 7, 10, and 22 which are secreted and sequestered in the extracellular matrix (ECM) . The association of FGF-BP with heparan sulfate proteoglycans (HSPG) weakens HSPG attachment of FGFs and promotes their release. FGF-BP enhances the mitogenic effects of FGFs, thereby contributing to epithelial, endothelial, and neuronal tissue repair, angiogenesis, and tumor growth.