Description
Fibroblast growth factor binding protein (FGF-BP), also known as HBp17, is a secreted glycoprotein that increases the bioavailability of FGFs (1). Mature FGF-BP is a 34 kDa O-glycosylated protein with five conserved intrachain disulfide bonds (2-4). FGF-BP contains a heparin-binding domain (aa 113-146) and a distinct FGF-binding region (aa 197-238) (5). Mature rat FGF-BP shares 54% and 81% aa sequence identity with mouse and rat FGF-BP, respectively. FGF-BP is expressed throughout development and in adult squamous epithelium (6, 7). It is upregulated in injured skin, renal tubular epithelium, and spinal nerves as well as in carcinomas of the skin, colon, and pancreas (3, 8-11). FGF-BP binds FGF -1, -2, -7, -10, and -22 which are secreted and sequestered in the extracellular matrix (ECM) (8, 12). The interactions of FGF-BP with heparin sulfate proteoglycans (HSPG) and FGF, modulates their activities (7, 9 13, 14). FGF-BP enhances the mitogenic effects of FGFs, thereby contributing to epithelial, endothelial, and neuronal tissue repair, angiogenesis, and tumor growth (8-10, 12, 15, 16)