Gating the activation and tuning the Ca2+ frequency response of CaM kinase II

门控 CaM 激酶 II 的激活并调节 Ca2 频率响应

• 批准号: 8737282
• 负责人: Howard Schulman
• 金额: $ 26.7万
• 依托单位: ALLOSTEROS THERAPEUTICS, INC.
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-30 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8737282
• 关键词: Affect; Architecture; Attention; Binding; Brain; Cardiac Myocytes; Catalytic Domain; Cell Nucleus; Cell membrane; Cell physiology; Cytosol; Dependence; Enzymes; Equilibrium; Frequencies; Genetic; Grant; Growth Factor; Heart; Heart Arrest; Heart Rate; Holoenzymes; Hormones; In Situ; Length; Link; Mediating; Mediator of activation protein; Memory; Molecular; Molecular Conformation; Neurons; Neurotransmitters; Phosphorylation; Phosphotransferases; Physiologic pulse; Physiological; Property; Protein Kinase; Proteins; Reactive Oxygen Species; Risk; Role; Second Messenger Systems; Series; Signal Transduction; Signaling Molecule; Site; Stimulus; Structure; Substrate Specificity; Testing; Tissues; base; calmodulin-dependent protein kinase II; cell type; inhibitor/antagonist; insight; meetings; oxidation; response; second messenger; tool

DESCRIPTION (provided by applicant): Gating the activation and tuning the Ca[2+] frequency response of CaM kinase II Ca[2+] functions as a second messenger for many signaling molecules, including neurotransmitters, hormones and growth factors. One of the central mediators of Ca[2+]/CaM action is the multifunctional CaM kinase II (CaMKII), a ubiquitous Ser/Thr protein kinase that phosphorylates dozens of key cellular proteins and enzymes in the cytosol, plasma membrane, and nucleus. The kinase has been the focus of considerable attention because i) it has a unique architecture with 12 kinase subunits that determine its Ca[2+]/CaM sensing, intracellular targeting, and substrate specificity; ii) it displays a form of molecular memory in which Ca[2+]-dependent autophosphorylation at a Thr residue and/or oxidation at a nearby Met residue switches it to a Ca[2+]-independent (autonomous) state that participates in neuronal memory and other functions; iii) it can respond to the frequency of Ca[2+]-linked stimulation, such as heart rate, and modifies cell function accordingly. Understanding the mechanism and structural basis by which CaMKII decodes the frequency of Ca[2+] spikes is therefore critical to understanding both its physiological and pathological functions. Based on a recent crystal structure and functional analysis of the kinase we hypothesize that the kinase undergoes an equilibrium between a compact structure where its catalytic domains are tightly packed into a central hub composed of its association domain and a more extended structure that is more readily activated by CaM. We will test whether the length of linker sequences between the catalytic and association domains tune the kinase to different frequencies of Ca[2+] spikes and how this is affected by oxidation. We will further examine the effects of gating of the autoinhibitory domain by a pharmacological inhibitor and by a SNP that is associated with increased risk of sudden cardiac arrest. We propose to test its remarkable properties by determining whether the kinase decodes the frequency of Ca[2+] stimuli delivered to cardiomyocytes to increase its autophosphorylation and phosphorylation of its substrates. Finally, we will use our structural and regulatory insights to develop an activator of CaMKII that can be used to evaluate and discover and delineate new CaMKII functions in diverse cell types.

描述（由申请人提供）：门控激活和调整CAM激酶II CA [2+]的Ca [2+]频率响应，作为许多信号分子的第二个使者，包括神经递质，激素和生长因子。 CA [2+]/CAM作用的中心介体之一是多功能CAM激酶II（CAMKII），这是一种无处不在的Ser/Thr蛋白激酶，可磷酸化细胞溶胶，质膜膜和核的数十种钥匙细胞蛋白和酶。激酶一直是引起大量关注的重点，因为i）它具有独特的架构，具有12个激酶亚基，可以确定其CA [2+]/CAM感应，细胞内靶向和底物特异性； ii）它显示了一种分子记忆的形式，其中Ca [2+] - 在THR残基处依赖性自磷酸化和附近的MED残基将其切换为CA [2+] - 独立（自主）状态，该状态参与神经元记忆和其他功能； iii）它可以响应Ca [2+]链接刺激（例如心率）的频率，并相应地修饰细胞功能。因此，了解CAMKII解码Ca [2+]尖峰的频率的机制和结构基础对于理解其生理和病理功能至关重要。基于最新的晶体结构和激酶的功能分析，我们假设激酶在紧凑的结构之间经历平衡，在紧凑的结构中，其催化结构域被紧密地堆积到由其关联域组成的中心轮毂中，并且更易于扩展的结构，该结构更容易被CAM激活。我们将测试催化和关联域之间的接头序列的长度是否将激酶调整为Ca [2+]尖峰的不同频率以及如何影响氧化的不同频率。我们将进一步研究药理学抑制剂以及与猝死风险增加的SNP对自身抑制域对裂开的影响。我们建议通过确定激酶是否解析传递到心肌细胞的Ca [2+]刺激的频率以增加其自磷酸化和其底物磷酸化的频率。最后，我们将使用我们的结构和法规见解来开发CAMKII的激活因子，该激活因子可用于评估和发现和描述各种细胞类型中的新CAMKII功能。