CaMKII activation and regulation in adult cardiac myocytes

项目总结/摘要 钙调素依赖性蛋白激酶（CaMKII）是心脏功能的重要调节因子， 在病理状态下，调节离子通道、钙转运体、肌丝 和核转录。CaMKII通常可以微调这些过程。但在病理学上， 慢性自主性CaMKII过度激活可使靶点过度磷酸化， 由于对几种离子通道和钙处理的急性作用，导致促性腺激素生成 proteins.慢性CaMKII激活也是几种病理状态和急性炎症的标志。 或遗传性CaMKII抑制可以减少心律失常和HF的进展。因此 理解心肌细胞中CaMKII调节的基本方面是至关重要的 了解功能障碍和潜在的治疗方法。我们和其他人发现了几个新的 翻译后修饰（PTM）可以将CaMKII捕获在激活状态，而不是 在局部钙瞬变的情况下快速开启和关闭。自磷酸化、氧化、GlcNAcylation 和S-亚硝基化在CaMKII上的调节热点内产生记忆和自主 活性，即使当Ca/CaM福尔斯下降。这些PTM之间的功能协同作用尚不清楚，但 将在Aim 1中的肌细胞中直接测量。有一种教条认为CaMKII-十二聚体 在肌细胞中既不交换亚基，也不明显移动，但我们的初步数据推翻了 这两个教条，这将在目标2中阐明。S-亚硝基化，最新的监管PTM， 可以促进自主激活（C290）或抑制Ca/CaM激活（C273）。目标3 将测试这些位点在成人心肌细胞和急性缺血/再灌注中的功能影响 和长期压力超负荷。我们将使用多种创新的荧光 工具和方法，以及动物来测试这3个主要的CaMKII目标。拟议的研究将 对我们理解CaMKII活性在心脏中的调节方式产生了重大影响， 促进病理学，可能是治疗干预的目标。

Project Summary/ Abstract Ca-Calmodulin dependent protein kinase (CaMKII) is an important regulator of cardiac function, and dysfunction in pathological states, regulating ion channels, Ca transporters, myofilaments and nuclear transcription. CaMKII may normally fine-tune these processes. But in pathological conditions chronic autonomous CaMKII over-activation can hyerphosphorylate targets, contributing to arrhythmogenesis due to acute effects on several ion channels and Ca-handling proteins. Chronic CaMKII activation is also a hallmark of several pathological states and acute or genetic CaMKII inhibition can reduce arrhythmias and the progression of HF. Thus understanding fundamental aspects of CaMKII regulation in cardiac myocytes is critical understanding dysfunction and potential therapeutics. We and others discovered several novel post-translational modifications (PTMs) that can trap CaMKII in an activated state, rather than turning on & off rapidly with local Ca transients. Autophosphorylation, oxidation, GlcNAcylation and S-nitrosylation within a regulatory hotspot on CaMKII creates memory and autonomous activity, even when Ca/CaM falls. The functional synergy among these PTMs is unknown, but will be directly measured in myocytes in Aim 1. Dogma has been that CaMKII-dodecamers neither exchange subunits nor move appreciably in myocytes, but our preliminary data upends both dogmas, and this will be elucidated in Aim 2. S-nitrosylation, the newest regulatory PTM, can either promote autonomous activation (C290) or inhibit Ca/CaM activation (C273). Aim 3 will test the functional impact of these sites in adult myocytes and in acute ischemia/reperfusion and long-term pressure overload in intact animals. We will use multiple innovative fluorescence tools and methods, and animals to test these 3 major CaMKII Aims. The proposed studies will have major impact on our understanding of how CaMKII activity is regulated in heart, in ways that promote pathology and might be targets for therapeutic intervention.