| 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 Mr=190 kDa 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?????s cytoplasmic domain. Signaling proteins that are phosphorylated and/or localized in response to c-Met phosphorylation include: Grb2, Shc, Cbl, Crk, cortactin, paxillin, GAB1, PI3K, FAK, Src, Ras, ERK1 and 2, JNK, PLC gamma, AKT, and STAT3. HGF/SF stimulation of c-Met expressing cells enhances proliferation, migration, morphogenesis, and protease synthesis, characteristics that are associated with invasive cell phenotype. Many types of cancer exhibit sustained c-Met stimulation, overexpression, or mutation, including carcinomas of the colon, breast, ovary, lung, liver, prostate, thyroid, kidney, as well as melanomas and sarcomas. In addition to cancer studies, other research areas in which c-Met is under investigation include organogenesis, organ regeneration, angiogenesis and surgical wound healing. |
