Cooperative Dimerization of Fibroblast Growth Factor 1 (FGF1) upon a Single Heparin Saccharide May Drive the Formation of 2:2:1 FGF1·FGFR2c·Heparin Ternary Complexes

The related glycosaminoglycans heparin and heparan sulfate are essential for the activity of the fibroblast growth factor (FGF) family as they form an integral part of the signaling complex at the cell surface. Using size-exclusion chromatography we have studied the capacities of a variety of heparin oligosaccharides to bind FGF1 and FGFR2c both separately and together in ternary complexes. In the absence of heparin, FGF1 had no detectable...