Rostas John A P, Hoffman Alexander, Murtha Lucy A, Pepperall Debbie, McLeod Damian D, Dickson Phillip W, Spratt Neil J, Skelding Kathryn A
School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, and Hunter Medical Research Institute, The University of Newcastle, Callaghan, NSW 2308, Australia.
School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, and Hunter Medical Research Institute, The University of Newcastle, Callaghan, NSW 2308, Australia.
Neurochem Int. 2017 Mar;104:6-10. doi: 10.1016/j.neuint.2017.01.002. Epub 2017 Jan 5.
Ischaemia/excitotoxicity produces persistent activation of CaMKII (Ca-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-αCaMKII transgenic mice that lack the ability to phosphorylate αCaMKII 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. Overexpression of the phospho-mimic mutant T286D-αCaMKII in differentiated neuroblastoma cell lines did not enhance excitotoxicity-induced cell death compared to overexpression of wild type αCaMKII. By contrast, overexpression of the phospho-mimic mutant T253D-αCaMKII significantly enhanced excitotoxicity-induced cell death whereas overexpression of the phospho-null mutant T253V-αCaMKII 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.
缺血/兴奋毒性会导致钙调蛋白激酶II（Ca-钙调蛋白刺激的蛋白激酶II，CaMKII）持续激活，进而引发细胞死亡。本研究调查了T286和T253位点的CaMKII磷酸化在产生这种持续激活过程中的作用。在T286A-αCaMKII转基因小鼠中，该小鼠缺乏在T286位点磷酸化αCaMKII的能力，大脑中动脉短暂闭塞90分钟后，与正常同窝对照相比，梗死面积无显著差异。与野生型αCaMKII过表达相比，在分化的神经母细胞瘤细胞系中过表达磷酸模拟突变体T286D-αCaMKII并没有增强兴奋毒性诱导的细胞死亡。相比之下，过表达磷酸模拟突变体T253D-αCaMKII显著增强了兴奋毒性诱导的细胞死亡，而过表达磷酸化缺失突变体T253V-αCaMKII则没有增强作用。这些结果表明，T286磷酸化在缺血/兴奋毒性诱导的CaMKII介导的细胞死亡中不起重要作用，并提示T253磷酸化是产生缺血/兴奋毒性诱导的细胞死亡中所涉及的CaMKII持续激活所必需的。
