Ca Regulation of Ca Channels

Ca 通道的 Ca 调节

• 批准号: 7265541
• 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/7265541
• 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; Operative Surgical Procedures; Pain; Pattern; Phase; Psychotic Disorders; Range; Regulation; Research; Signal Transduction; Signaling Molecule; Source; Surface; System; Testing; Therapeutic; Total Internal Reflection Fluorescent; base; design; insight; nanometer; next generation; novel; 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）：在过去的赠款周期中，CA渠道家族的钙调蛋白（CAM）调节的一般规则被辨别。 CAM有两个裂片，每个裂片都有两个Ca2+结合位点。第一个一般方面是，每个叶可以自主触发一种通道调节的形式。其次，每当CAM（C-LOBE）的C末端叶触发通道调节时，对局部CA2+信号的响应性就会优先。相反，无论N末端叶（N-LOBE）启动调节，全局CA2+信号都有选择性。第三，有理由期望这种操作规则将CA通道超出CA通道超出CAM与目标分子相关的许多复合物。因为CA通道（和其他信号分子）的CAM调节对于正常的神经化学方法至关重要，并且对于与疼痛，精神病和心脏心律失常发生有关的治疗剂可能很重要，因此回答这些通用规则是如何发生的，这是下一个研究周期的总体推力。三个目标将解决这个总体主题。 1。开发和执行针对CAM/CA通道复合物的动力学CA2+解码机理的基本测试。这个目标为凸轮解码的发生方式提出了“动力学CA2+解码”理论，并设计了新型的电压块“实验，以实现该理论的基本检验。 2。为了设计CAM/CA通道调节的局部/全局CA2+偏好，作为动力学CA2+解码理论的高阶测试，以及用于开发新型通道调节剂的设计原理的手段。动力学CA2+解码理论的主要预测是，通道调节的局部/全局CA2+偏好反映了CA2+结合的通道亲和力之间的竞争与CAM叶的无用形式。 AIM 2将改变这些亲和力，并检查CA2+偏好的预测变化。 AIM 2还将探索这些修饰是否可以为以新方式调节通道调节的药物化合物的设计提供信息。 3。通过实验确定Ca通道纳米内的Ca2+浓度和扩散。对于下一阶段的进步至关重要的是在实际的“纳米域”环境中直接测量局部和全局Ca2+浓度信号以及Ca2+扩散。遗传编码的Ca2+传感器（TNL-15）的融合与通道的融合，结合TIRF显微镜有望揭示这些长期追求的实体。这些目的有望大胆的进步，并具有基本和应用的后果。