Ca Regulation of Ca Channels

Ca 通道的 Ca 调节

• 批准号: 7886484
• 负责人: DAVID T YUE
• 金额: $ 34.85万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7886484
• 关键词: Address; Affinity; Avidity; Binding; Binding Sites; Biological; C-terminal; Calmodulin; Cardiac; Complex; Diffusion; Drug Compounding; Engineering; Environment; Family; Glean; Grant; Individual; Kinetics; Lobe; Measurement; Mediating; Modification; N-terminal; Neurons; Pain; Pattern; Phase; Psychotic Disorders; Regulation; Research; Signal Transduction; Signaling Molecule; Source; Surface; System; Testing; Therapeutic; Total Internal Reflection Fluorescent; base; design; insight; nanometer; next generation; novel; operation; preference; research study; sensor; theories; voltage

DESCRIPTION (provided by applicant): Over the past grant cycle, general rules for calmodulin (CaM) regulation of the family of Ca channels were discerned. CaM has two lobes, each with two Ca2+ binding sites. A first general aspect was that each lobe can autonomously trigger a form of channel regulation. Secondly, whenever the C-terminal lobe of CaM (C-lobe) triggers channel regulation, there is preferential responsiveness to local Ca2+ signals. Conversely, wherever the N-terminal lobe (N-lobe) initiates regulation, there is selectivity for global Ca2+ signals. Thirdly, there is reason to expect that this rule of operation generalizes beyond Ca channels, to many complexes in which CaM is preassociated with target molecules. Because CaM regulation of Ca channels (and other signaling molecules) is crucial for normal neuroprocessing, and likely important for therapeutics relating to pain, psychosis, and cardiac arrhythmogenesis, answering how these general rules occur is the overarching thrust for the next cycle of research. Three aims will address this overall theme. 1. To develop and perform elementary tests of a kinetic Ca2+ decoding mechanism for the CaM/Ca channel complex. This aim formulates a 'kinetic Ca2+ decoding' theory of how the CaM decoding occurs, and devises novel Voltage-block' experiments to enable elementary tests of this theory. 2. To engineer the local/global Ca2+ preference of CaM/Ca channel regulation, as a higher-order test of the kinetic Ca2+ decoding theory, and as means to glean design principles for developing novel channel modulators. A principal prediction of the kinetic Ca2+ decoding theory is that the local/global Ca2+ preference of channel regulation reflects competition between channel affinities for the Ca2+-bound and Ca2+-free forms of a lobe of CaM. Aim 2 will alter these affinities and check for the predicted changes in Ca2+ preference. Aim 2 will also explore whether these modifications can inform the design of drug compounds that modulate channel regulation in new ways. 3. To experimentally determine Ca2+ concentrations and diffusion within the nanometers of the Ca channel. Crucial to the next phase of progress is the direct measurements of local and global Ca2+ concentration signals, and Ca2+ diffusion, in the actual channel 'nanodomain' environment. Fusions of a genetically-encoded Ca2+ sensor (TNL-15) to channels, combined with TIRF microscopy promise to reveal these long sought-after entities. These aims promise bold progress, with basic and applied ramifications.

描述(由申请人提供)：在过去的资助周期中，发现了钙通道家族钙调素(CaM)调节的一般规则。CaM有两个叶，每个叶有两个钙结合部位。第一个总体方面是，每个叶可以自主地触发一种形式的通道调节。其次，当CaM的C-末端叶(C-叶)触发通道调节时，对局部钙信号具有优先反应性。相反，在N-末端叶(N-叶)启动调节的任何地方，都有全球钙信号的选择性。第三，有理由预期，这一操作规则不仅适用于钙通道，还适用于许多CaM与目标分子预先关联的复合体。由于CaM对钙通道(和其他信号分子)的调节对正常的神经加工至关重要，而且可能对与疼痛、精神病和心律失常发生相关的治疗很重要，因此回答这些一般规律是如何发生的是下一轮研究的首要推动力。三个目标将针对这一总体主题。1.建立和进行钙调素/钙通道复合体的动力学钙离子解码机制的初步测试。这一目标形成了一个关于CaM解码如何发生的“动力学钙解码”理论，并设计了新颖的电压块实验来实现对该理论的初步测试。2.设计钙调素/钙通道调节的局部/全局钙偏好，作为动力学钙解码理论的高阶检验，并为开发新的通道调节剂收集设计原则。动力学钙解码理论的一个主要预测是，通道调节的局部/全局钙偏好反映了通道亲和力对CaM叶的钙结合形式和无钙形式的竞争。目标2将改变这些亲和力，并检查钙离子偏好的预测变化。目标2还将探索这些修饰是否可以为以新方式调节通道的药物化合物的设计提供信息。3.实验测定钙离子通道纳米尺度内的钙离子浓度和扩散。对下一阶段的进展至关重要的是，在实际的通道“纳米域”环境中，直接测量局部和全球的钙离子浓度信号以及钙离子扩散。基因编码的钙传感器(TNL-15)与通道的融合，与TIRF显微镜相结合，有望揭示这些长期受到追捧的实体。这些目标承诺取得大胆的进展，并产生基本的和应用的后果。