CaM-kinase II (CAMK2) is a prominent kinase in the central nervous system. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Autophosphorylation of CAMK2 plays an important role in the regulation of the kinase activity. CAMK2 is composed of four different chains: alpha, beta, gamma, and delta. The different isoforms assemble into homo- or heteromultimeric holoenzymes composed of 8 to 12 subunits (By similarity). First detected at the 18-somite stage where expression is restricted to somite boundaries. At 24 hpf, expression is elevated in epidermal tissue and in the hatching gland. After 24 hpf, expression dimishes, but persists at low levels along the dorsal trunk. At 48 hpf, expression is restricted at a low level to the forebrain. At 72 hpf, weak expression reappears along the entire dorsal trunk in discrete cell bodies. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. CaMK subfamily.