FGF-4 is a heparin binding growth factor that is a member of the FGF family. Proteins of this family play a central role during prenatal development and postnatal growth and regeneration of a variety of tissues, by promoting cellular proliferation and differentiation. FGF-4 signals through the FGFR 1c, 2c, 3c, and 4. Recombinant human FGF-4 is a 19.7 kDa protein consisting of 182 amino acid residues.