Ischaemia- and excitotoxicity-induced CaMKII-Mediated neuronal cell death: The relative roles of CaMKII autophosphorylation at T286 and T253

Ischaemia/excitotoxicity produces persistent activation of CaMKII (Ca2+-calmodulin stimulated protein kinase II) that initiates cell death. This study investigated the involvement of CaMKII phosphorylation at T286 and T253 in producing this persistent activation. In T286A-alpha CaMKII transgenic mice that lack the ability to phosphorylate alpha CaMKII at T286, transient occlusion of the middle cerebral artery for 90 min resulted in no significant difference in infarct size compared to normal littermate controls. Over-expression of the phospho-mimic mutant T286D-alpha CaMKII in differentiated neuroblastoma cell lines did not enhance excitotoxicity-induced cell death compared to overexpression of wild type KaMKII. By contrast, overexpression of the phospho-mimic mutant T253D-alpha CaMKII significantly enhanced excitotoxicity-induced cell death whereas overexpression of the phospho-null mutant T253V-alpha CaMKII produced no enhancement. These results indicate that T286 phosphorylation does not play a significant role in ischaemia/excitotoxicity induced CaMKII-mediated cell death and suggest that T253 phosphorylation is required to produce the persistent activation of CaMKII involved in ischaemia/excitotoxicity induced cell death. (C) 2017 Elsevier Ltd. All rights reserved.