Fibroblast growth factors (FGFs), a heparin binding growth factor, exhibit widespread mitogenic and neurotrophic activities in a variety of different cells including mesenchymal, neuroectodermal and endothelial cells. aFGF (FGF-1) and bFGF (FGF-2) are present in relatively high levels in CNS. aFGF is expressed by a subset of neuronal populations, while bFGF is expressed by astrocytes, both lack signal peptides. Human bFGF is a 17.2kD protein containing 155 amino acid residues. The heparin-binding growth factors are angiogenic agents in vivo and are potent mitogens for a variety of cell types in vitro. There are differences in the tissue distribution and concentration of these 2 growth factors. Subunit: Monomer. Interacts with CSPG4 and FGFBP1. Found in a complex with FGFBP1, FGF1 and FGF2. This protein binds heparin more strongly than does aFGF. Belongs to the heparin-binding growth factors family.