Binding of the complex of calcium and calmodulin (CALM1:4xCa2+) to CaMKII dodecamer, upon calcium influx through activated NMDA receptors, activates the kinase activity of CaMKII, leading to CaMKII autophosphorylation on threonine residue T286 (T286 in the alpha isoform of CaMKII corresponds to T287 in the beta isoforms of CaMKII). Autophosphorylation increases the affinity of CaMKII for calmodulin, but once autophosphorylated, CaMKII remains partially catalytically active even after dissociation of calmodulin (Schworer et al. 1986, Meyer et al. 1992).