Structural and Functional Diversity in the FGf Receptor Multigene Family

The fibroblast growth factors (FGFs) constitute a family of closely related polypeptide mitogens. There are seven members of this family, identified on the basis of amino acid sequence homologies. The FGF family has distinguished itself from other growth factor families by virtue of the pleiotropic actions of its members. This chapter discusses the structural and functional diversity in the FGF receptor multigene family. The effects of FGFs are known to be mediated by high-affinity receptor tyrosine kinases. The structurally diverse receptor molecules are also functionally different. The characterization of structural and functional diversity within the FGF receptor shows the differences in the mechanisms of action among members of the FGF family. The first members of the FGF family to be purified and characterized were acidic FGF (aFGF) and basic FGF (bFGF), which are purified on the basis of their mitogenicity toward fibroblasts by using bovine pituitary. Functional differences among the different receptor forms are observed in the chapter at two levels. The long-range goal of designing the effective agonist and antagonists of FGF action has considerable therapeutic value.