Calcium/calmodulin-dependent protein kinase that operates in the calcium-triggered CaMKK-CaMK1 signaling cascade and, upon calcium influx, activates CREB-dependent gene transcription, regulates calcium-mediated granulocyte function and respiratory burst and promotes basal dendritic growth of hippocampal neurons. In neutrophil cells, required for cytokine-induced proliferative responses and activation of the respiratory burst. Activates the transcription factor CREB1 in hippocampal neuron nuclei. May play a role in apoptosis of erythroleukemia cells. In vitro, phosphorylates transcription factor CREM isoform Beta. 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 results in conformational change that relieves intrasteric autoinhibition and allows phosphorylation of Thr-180 within the activation loop by CaMKK1 or CaMKK2. Phosphorylation of Thr-180 results in several fold increase in total activity. Unlike CaMK4, may be unable to exhibit autonomous activity after Ca(2+)/calmodulin activation. Predominantly cytoplasmic. Nuclear localization increases upon activation by KCl treatment in hippocampal neurons. Widely expressed. Highly and mostly expressed in polymorphonuclear leukocytes (neutrophilic and eosinophilic granulocytes) while little or no expression is observed in monocytes and lymphocytes. Expressed during hippocampal formation with high expression in the pyramidal cell layers. Expression increases upon treatment of EC cells with DMSO and retinoic acid. Induced by KCL in PC12 cells. The autoinhibitory domain overlaps with the calmodulin binding region and interacts in the inactive folded state with the catalytic domain as a pseudosubstrate. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. CaMK subfamily.