Catalytic domain of the Protein Tyrosine Kinases, Met and Ron
PTKs catalyze the transfer of the gamma-phosphoryl group from ATP to tyrosine (tyr) residues in protein substrates. Met and Ron are receptor PTKs (RTKs) composed of an alpha-beta heterodimer. The extracellular alpha chain is disulfide linked to the beta chain, which contains an extracellular ligand-binding region with a sema domain, a PSI domain and four IPT repeats, a transmembrane segment, and an intracellular catalytic domain. Binding to their ligands leads to receptor dimerization, autophosphorylation, activation, and intracellular signaling. Met binds to the ligand, hepatocyte growth factor/scatter factor (HGF/SF), and is also called the HGF receptor. HGF/Met signaling plays a role in growth, transformation, cell motility, invasion, metastasis, angiogenesis, wound healing, and tissue regeneration. Aberrant expression of Met through mutations or gene amplification is associated with many human cancers including hereditary papillary renal and gastric carcinomas. The ligand for Ron is macrophage stimulating protein (MSP). Ron signaling is important in regulating cell motility, adhesion, proliferation, and apoptosis. Aberrant Ron expression is implicated in tumorigenesis and metastasis. The Met/Ron subfamily is part of a larger superfamily that includes the catalytic domains of other kinases such as protein serine/threonine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.
Jiyao W et al.(2023). "The conserved domain database in 2023.",