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

基本信息

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
项目类别：
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

项目摘要

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 CaM 激酶 II 的激活并调节 Ca[2+] 频率响应 Ca[2+] 充当许多信号分子（包括神经递质、激素和生长因子）的第二信使。 Ca[2+]/CaM 作用的中心介质之一是多功能 CaM 激酶 II (CaMKII)，这是一种普遍存在的 Ser/Thr 蛋白激酶，可磷酸化细胞质、质膜和细胞核中的数十种关键细胞蛋白和酶。该激酶已成为人们广泛关注的焦点，因为 i) 它具有独特的结构，包含 12 个激酶亚基，决定了其 Ca[2+]/CaM 传感、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 Thr 残基处的 Ca[2+] 依赖性自磷酸化和/或附近 Met 残基处的氧化将其转换为参与 Ca[2+] 独立（自主）状态神经元记忆和其他功能； iii) 它可以对 Ca[2+] 相关刺激的频率（例如心率）做出反应，并相应地改变细胞功能。因此，了解 CaMKII 解码 Ca[2+] 尖峰频率的机制和结构基础对于了解其生理和病理功能至关重要。根据最近对激酶的晶体结构和功能分析，我们假设激酶在紧凑的结构和更容易激活的更延伸的结构之间达到平衡，在紧凑的结构中，其催化结构域紧密地堆积在由其关联结构域组成的中心枢纽中。由卡姆。我们将测试催化域和关联域之间的连接序列的长度是否将激酶调节到不同的 Ca[2+] 尖峰频率，以及氧化对此有何影响。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 门控自抑制结构域的影响。我们建议通过确定激酶是否解码递送至心肌细胞的 Ca[2+] 刺激的频率来测试其显着特性，以增加其自身磷酸化及其底物的磷酸化。最后，我们将利用我们的结构和调控见解来开发 CaMKII 激活剂，可用于评估、发现和描述不同细胞类型中的新 CaMKII 功能。