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

中枢神经系统的突触可塑性被认为对学习和记忆等高级大脑功能至关重要，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Ca^<2+>/calmodulin依赖性蛋白激酶II （calmodulin kinase II,CaMKII）的蛋白磷酸化。CaMKII是一种特别富集于神经系统的多功能蛋白激酶，与多种神经元功能有关，但其调控的确切机制及其在活体动物中的作用尚不清楚。为了获得一种有效的工具来了解CaMKII在体内突触可塑性中的作用，研究者首先尝试寻找能够在体内充分抑制CaMKII表达的针对CaMKII的反义寡脱氧核苷酸（antisense ODN）。尽管在体外使用过表达CaMKII的神经母细胞瘤细胞系大力筛选反义ODN，但没有发现有效的候选物。作为另一种工具，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，这些抗体只有在CaMKII被激活后才能识别CaMKII，即自磷酸化，并利用这些抗体来了解CaMKII在体内对急性神经元兴奋的生理调节。研究表明，CaMKII的活化、自磷酸化状态在体内受到动态、精确的调控，证明这些抗体是评价CaMKII功能意义的有力工具。这些抗体的进一步应用，以了解CaMKII在突触可塑性中的作用，以及新的遗传方法来调节CaMKII在体内的表达，将是研究者未来的研究方向。

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.