c-MET

c-MET

c-MET, also known as MET, is a receptor tyrosine kinase that, after binding with its ligand, hepatocyte growth factor, activates a wide range of different cellular signaling pathways, including those involved in proliferation, motility, migration and invasion. c-MET is encoded by the MET gene, and it transduces signals from the extracellular matrix into the cytoplasm by binding to hepatocyte growth factor/HGF ligand. c-MET is a heterodimer made of an alpha chain (50 kDa) and a beta chain (145 kDa), which are disulfide linked. Ligand binding at the cell surface induces autophosphorylation of MET on its intracellular domain that provides docking sites for downstream signaling molecules. Following activation by ligand, MET interacts with the PI3-kinase subunit PIK3R1, PLCG1, SRC, GRB2, STAT3 or the adapter GAB1. Recruitment of these downstream effectors by MET leads to the activation of several signaling cascades, including the RAS-ERK, PI3 kinase-AKT, or PLCgamma-PKC. In its inactive state, the C-terminal tail interacts with the catalytic domain and inhibits the kinase activity. Upon ligand binding, the C-terminal tail is displaced and becomes phosphorylated, thus increasing the kinase activity. Genetic polymorphisms, chromosomal translocation, overexpression, and additional splicing and proteolytic cleavage of c-MET have been described in a wide range of cancers.