Calcium/calmodulin-dependent protein kinase belonging to a proposed calcium-triggered signaling cascade. In vitro phosphorylates transcription factor CREB1. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Activated by Ca(2+)/calmodulin. Binding of calmodulin is thought to result in a conformational change and leads to activation through phosphorylation by CAMKK1. Highly expressed in brain, in neuronal cell bodies of the central nucleus of amygdala and ventromedial hypothalamic nucleus. Also detected in heart, testis, and kidney. Expression starts at 11 dpc in parallel with the onset of development of the central nervous system. The autoinhibitory domain overlaps with the calmodulin binding region and interacts in the inactive folded state with the catalytic domain as a pseudosubstrate. May be prenylated on Cys-474. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. CaMK subfamily.