Diversity does make a difference: fibroblast growth factor-heparin interactions.

Fibroblast growth factors (FGFs) are members of a protein family with a broad range of biological activities. The best characterized FGFs interact with two distinct extracellular receptors--a transmembrane tyrosine kinase FGF receptor (FGFR) and a heparan f1p4ate-related proteoglycan of the extracellular matrix. These components form a FGF-FGFR-proteoglycan complex that activates the FGF-mediated signal transduction process through FGFR dimerization. Recent crystal structure determinations of FGF-heparin complexes have provided insights into both the interactions between these components and the role of heparin-like proteoglycans in FGF function. Future advances in this field will benefit enormously from an ability to specifically prepare homogeneous heparin-based oligosaccharides of defined sequence for use in biochemical and structural studies of FGF and many other systems.