Catalytic domain of the Serine/Threonine Kinase, Novel Protein Kinase C delta
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. PKC-delta plays a role in cell cycle regulation and programmed cell death in many cell types. It slows down cell proliferation, inducing cell cycle arrest and enhancing cell differentiation. PKC-delta is also involved in the regulation of transcription as well as immune and inflammatory responses. It plays a central role in the genotoxic stress response that leads to DNA damaged-induced apoptosis. 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. The nPKC-delta 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.