CaMKII (Calcium/calmodulin-dependent protein kinase II) is a ubiquitous serine/threonine protein kinase that is abundant in the brain as a major constituent of the postsynaptic density (PSD). The enzyme is an oligomeric protein composed of distinct but related subunits, alpha, beta, gamma, and delta, each encoded by a separate gene. CAMK2A assembles into heterooligomeric complexes with other CAMK2 subunits.CaMKII is a prominent kinase in the central nervous system that may function in long term potentiation and neurotransmitter release.