FGF1 (Heparin-binding growth factor 1, Acidic fibroblast growth factor) and FGF2 (Basic FGF) are angiogenic agents in vivo and potent mitogens for a variety of cell types in vitro. There are differences between these heparin-binding growth factors in tissue distribution and concentration. FGF1 binds FGFR2, forming a ternary comple, Xenopus/Amphibian, of two molecules each of FGFR2 and FGF1 for one heparin molecule. Interacts with FGFBP1 and forms a comple, Xenopus/Amphibian, with FGF2 and FGFBP1.