Fibroblast growth factors (FGFs) produce mitogenic and angiogenic effects in target cells by signaling through cell surface receptor tyrosine kinases. There are four members of the FGF receptor family: FGFR1-4. Each receptor contains an extracellular ligand binding domain, a transmembrane domain, and a cytoplasmic kinase domain. Following ligand binding and dimerization, the receptors are phosphorylated at specific tyrosine residues. Alternatively spliced variants which encode different protein isoforms have been described; however, not all variants have been fully characterized.
