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: 8550104
• 负责人: Howard Schulman
• 金额: $ 25.77万
• 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/8550104
• 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)：控制CaM激酶II的激活和调节Ca[2+]的频率响应Ca[2+]作为许多信号分子的第二信使，包括神经递质、激素和生长因子。多功能钙调素蛋白激酶II(CaMKII)是Ca[2+]/CaM作用的中心介质之一，它是一种普遍存在的丝氨酸/苏氨酸蛋白激酶，可磷酸化胞浆、质膜和细胞核中的许多关键蛋白和酶。该激酶一直是人们关注的焦点，因为i)它有一个独特的结构，由12个亚基组成，决定了它的钙[2+]/CaM感知、细胞内靶向和底物特异性；ii)它表现出一种分子记忆形式，其中苏氨酸残基上依赖钙离子的自动磷酸化和/或附近蛋氨酸残基上的氧化将它转换到参与神经元记忆和其他功能的钙[2+]非依赖性(自主)状态；iii)它可以响应钙[2+]连接的刺激的频率，如心率，并相应地改变细胞功能。因此，了解CaMKII解码钙离子尖峰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。根据最近对该蛋白的晶体结构和功能分析，我们推测该蛋白经历了一个紧凑的结构和一个更易被CaM激活的延伸结构之间的平衡。我们将测试催化结构域和结合结构域之间的连接子序列的长度是否将激酶调节到不同的Ca[2+]尖峰频率，以及氧化如何影响这一点。我们将进一步研究药物抑制剂和与心脏骤停风险增加相关的SNP对自身抑制域门控的影响。我们建议通过确定该激酶是否解码传递给心肌细胞的钙离子刺激的频率以增加其底物的自磷酸化和磷酸化来测试其显著的特性。最后，我们将利用我们的结构和调控洞察力开发一种CaMKII激活剂，可用于评估、发现和描绘不同细胞类型中的新CaMKII功能。