Catalytic domain of an Uncharacterized group of Serine/Threonine kinases with similarity to Calcium/calmodulin-dependent protein kinases
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. This subfamily is composed of uncharacterized STKs with similarity to CaMKs, which are multifunctional calcium and calmodulin (CaM) stimulated STKs involved in cell cycle regulation. The CaMK family includes CaMKI, CaMKII, CaMKIV, and CaMK kinase (CaMKK). CaMKs contain an N-terminal catalytic domain followed by a regulatory domain that harbors a CaM binding site. This uncharacterized subfamily is part of a larger superfamily that includes the catalytic domains of other protein kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.