Catalytic domain of PCTAIRE-like Serine/Threonine Kinases
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. PCTAIRE-like proteins show unusual expression patterns with high levels in post-mitotic tissues, suggesting that they may be involved in regulating post-mitotic cellular events. They share sequence similarity with Cyclin-Dependent Kinases (CDKs), which belong to a large family of STKs that are regulated by their cognate cyclins. Together, CDKs and cyclins are involved in the control of cell-cycle progression, transcription, and neuronal function. The association of PCTAIRE-like proteins with cyclins has not been widely studied, although PFTAIRE-1 has been shown to function as a CDK which is regulated by cyclin D3 as well as the membrane-associated cyclin Y. The PCTAIRE-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.