?
Catalytic domain of the Protein Tyrosine Kinases, Discoidin Domain Receptors PTKs catalyze the transfer of the gamma-phosphoryl group from ATP to tyrosine (tyr) residues in protein substrates. The DDR subfamily consists of homologs of mammalian DDR1, DDR2, and similar proteins. They are receptor PTKs (RTKs) containing an extracellular discoidin homology domain, a transmembrane segment, an extended juxtamembrane region, and an intracellular catalytic domain. The binding of the ligand, collagen, to DDRs results in a slow but sustained receptor activation. DDRs regulate cell adhesion, proliferation, and extracellular matrix remodeling. They have been linked to a variety of human cancers including breast, colon, ovarian, brain, and lung. There is no evidence showing that DDRs act as transforming oncogenes. They are more likely to play a role in the regulation of tumor growth and metastasis. The DDR 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.
|