Catalytic domain of the Serine/Threonine Kinases, Novel Protein Kinase C theta, delta, and similar proteins
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. PKC-theta is selectively expressed in T-cells and plays an important and non-redundant role in several aspects of T-cell biology. PKC-delta plays a role in cell cycle regulation and programmed cell death in many cell types. PKCs are classified into three groups (classical, atypical, and novel) depending on their mode of activation and the structural characteristics of their regulatory domain. nPKCs are calcium-independent, but require DAG (1,2-diacylglycerol) and phosphatidylserine (PS) for activity. There are four nPKC isoforms, delta, epsilon, eta, and theta. The nPKC-theta-like subfamily is part of a larger superfamily that includes the catalytic domains of other STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.
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