c-Met, a member of the tyrosine kinase superfamily, is the receptor for hepatocyte growth factor, also known as scatter factor (HGF/SF). The mature c-Met protein is a disulfide-linked heterodimer with Mr190kD composed of a heavily glycosylated alpha subunit that is completely extracellular in localization, and a beta subunit comprising an extracellular ligand binding domain, a single transmembrane domain, and a cytoplasmic tyrosine kinase domain. Cells expressing c-Met include epithelial cells, endothelial cells, blood cells of various types, and glomerular mesenchymal cells. HGF/SF binding to c-Met stimulates receptor dimerization and the phosphorylation of numerous residues within the receptor