| abstract |
Catalytic domain of the Serine/Threonine kinase, Calcium/calmodulin-dependent protein kinase Type II. STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. CaMKs are multifunctional calcium and calmodulin (CaM) stimulated STKs involved in cell cycle regulation. There are several types of CaMKs including CaMKI, CaMKII, and CaMKIV. CaMKs contain an N-terminal catalytic domain followed by a regulatory domain that harbors a CaM binding site. In addition, CaMKII contains a C-terminal association domain that facilitates oligomerization. There are four CaMKII proteins (alpha, beta, gamma, delta) encoded by different genes; each gene undergoes alternative splicing to produce more than 30 isoforms. CaMKII-alpha and -beta are enriched in neurons while CaMKII-gamma and -delta are predominant in myocardium. CaMKII is a signaling molecule that translates upstream calcium and reactive oxygen species (ROS) signals into downstream responses that play important roles in synaptic function and cardiovascular physiology. It is a major component of the postsynaptic density and is critical in regulating synaptic plasticity including long-term potentiation. It is critical in regulating ion channels and proteins involved in myocardial excitation-contraction and excitation-transcription coupling. Excessive CaMKII activity promotes processes that contribute to heart failure and arrhythmias. The CaMKII 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. |