The Role of Ca^<2+>/Calmodulin-Dependent Protein Kinase II in Synaptic Plasticity.

中枢神经系统中的突触可塑性被认为对于大脑的高级功能如学习和记忆是重要的，并且对其基本机制的理解是当今神经科学最重要的课题之一。首席研究员一直致力于突触可塑性的分子机制，特别强调通过Ca^<2+>/钙调蛋白依赖性蛋白激酶II（钙调蛋白激酶II，CaMK II）的蛋白磷酸化。CaMK Ⅱ是一种多功能蛋白激酶，尤其是在神经系统中富集，参与多种神经元功能，但其确切的调节机制及其在活体动物中的作用尚未阐明。为了在体内研究CaMK Ⅱ在突触可塑性中的作用，本研究首先寻找能在体内有效抑制CaMK Ⅱ表达的CaMK Ⅱ反义寡核苷酸（antisense oligodeoxynucleotides，反义ODN）。作为另一个工具，研究者已经成功地产生了针对CaMKII的磷酸化状态特异性抗体，该抗体仅在CaMKII被激活后才识别CaMKII，即，自磷酸化，并使用这些抗体来了解CaMKII在体内响应急性神经元兴奋的生理调节。该研究表明，CaMK II的活化、自磷酸化状态在体内处于动态和精确的调节下，并证明这些抗体是评价CaMK II功能意义的有力工具。进一步应用这些抗体来了解CaMK II在突触可塑性中的作用，以及体内调节CaMK II表达的新的遗传方法，研究者将在未来继续研究。

Synaptic plasticity in the central nervous system is thought to be important for the higher brain functions such as learning and memory, and the understanding of its fundamental mechanisms is one of the most important subjects of neuroscience today. The head investigator has been working on the molecular mechanisms of synaptic plasticity, with special emphasis on protein phosphorylation by Ca^<2+>/calmodulin-dependent protein kinase II (calmodulin kinase II,CaMKII). CaMKII is a multifunctional protein kinase especially enriched in the nervous system and has been implicatedin a variety of neuronal funcrions, but the precise mechanisms of its regulation and its role in living animals have not been clarified yet. In order to get an effective tool to understand the role of CaMKII in synaptic plasticity in vivo, the investigator first tried to search for antisense oligodeoxynucleotides (antisense ODN) against CaMKII which could sufficiently supress CaMKII expression in vivo. Despite the vigorous screening of antisense ODN using a neuroblastoma cell line overexpressing CaMKII in vitro, no effective candidate was found. As another tool, the investigator has succeeded in generating phosphorylation state-specific antibodies toward CaMKII which recognize CaMKII only after it is activated, i.e., autophosphorylated, and used these antibodies to understand the physiological regulation of CaMKII in response to acute neuronal excitation in vivo. The study showed that the activated, Autophosphorylated state of CaMKII was under dynamic and precise regulation in vivo, and proved these antibodies as powerful tools for the evaluation of the functional significance of CaMKII.Further application of these antibodies to understand the role of CaMKII in synaptic plasticity, as well as novel genetic approaches to regulate the expression of CaMKII in vivo, will be pursued by the investigator in the future.