Molecular mechanisms for regulation of HCN channels by TRIP8b subunits

TRIP8b 亚基调节 HCN 通道的分子机制

• 批准号: 8092046
• 负责人: William N Zagotta
• 金额: $ 19.5万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-15 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8092046
• 关键词: Action Potentials; Amino Acids; Behavior; Binding; Brain; Brain Pathology; C-terminal; Cardiac; Cartoons; Cations; Cells; Complex; Crystallography; Cyclic AMP; Cyclic Nucleotides; Cytoplasmic Protein; Dendrites; Dependence; Electrophysiology (science); Environment; Epilepsy; Fire - disasters; Fluorescence; Functional disorder; Goals; Grant; Ion Channel; Measures; Membrane; Membrane Potentials; Methods; Molecular; Mutation; Neurons; Pathogenesis; Physiology; Property; Protein Binding; Protein Isoforms; Proteins; Regulation; Resolution; Rest; Role; Specificity; Spices; Structure; Surface; Synapses; Thinking; Transistors; cyclic-nucleotide gated ion channels; electrical property; improved; nervous system disorder; neuronal excitability; research study; response; single molecule; stoichiometry; structural biology; trafficking; voltage

DESCRIPTION (provided by applicant): The fundamental ability of a neuron to fire action potentials in response to synaptic input is largely determined by the electrical properties of its dendrites. One key ion channel that regulates the electrical properties of dendrites is the hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channel. HCN channels operate at the threshold of excitability so small changes in the number, localization, voltage dependence, and cyclic nucleotide dependence of the channels can have a dramatic impact on the excitability of the cell. Our long term goal is to understand the molecular mechanisms for how HCN channels control neuronal excitability. Recently an auxiliary subunit of HCN channels in neurons was discovered, called TRIP8b. TRIP8b has a profound effect on the trafficking, voltage dependence, and cyclic nucleotide dependence of the HCN channels. In this grant, we propose to study the molecular mechanism for how TRIP8b binds to the HCN channel and regulates channel function. Our approach will be to combine x-ray crystallography, for atomic resolution structural information, with electrophysiology and fluorescence to study the functional channel in its native membrane environment. Our experiments will reveal the structure of the interaction between the HCN2 C-terminal region and TRIP8b at atomic resolution, the stoichiometry of the interaction, and the mechanism for TRIP8b regulation of the cyclic nucleotide-dependent and voltage- dependent gating of HCN2. These findings will provide a significant advance in our understanding of the structure and regulation of HCN channels as they exist in the neuron and further illuminate their role in the physiology and pathology of the brain. PUBLIC HEALTH RELEVANCE: Ion channels are the transistors of the brain and thereby control everything from our senses to our thoughts. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are fundamentally involved in the electrical excitability of the neurons in our brain, and their dysfunction is responsible for some neurological diseases such as epilepsy. Our long term goal is to understand the molecular mechanisms for how HCN channels control neuronal excitability to enable us to develop targeted therapies for neurological diseases.

描述（由申请人提供）：神经元对响应突触输入发射动作电位的基本能力在很大程度上取决于其树突的电性能。调节树突电性能的一个关键离子通道是超极化激活的环状核苷酸门控（HCN）离子通道。 HCN通道在兴奋性的阈值下运行，因此，通道的数量，定位，电压依赖性和环状核苷酸依赖性的较小变化可能会对细胞的兴奋性产生巨大影响。我们的长期目标是了解HCN通道如何控制神经元兴奋性的分子机制。最近发现了神经元中HCN通道的辅助亚基，称为Trip8b。 TRIP8B对HCN通道的运输，电压依赖性和环状核苷酸依赖性具有深远的影响。在这笔赠款中，我们建议研究TRIP8B如何与HCN通道结合并调节通道功能的分子机制。我们的方法是将X射线晶体学，原子分辨率的结构信息与电生理学和荧光相结合，以在其天然膜环境中研究功能通道。我们的实验将揭示HCN2 C末端区域与TRIP8B在原子分辨率下的相互作用的结构，相互作用的化学计量以及TRIP8B调节循环核苷酸依赖性和依赖性电压的HCN2的机制。这些发现将在我们对HCN通道的结构和调节中存在的结构和调节，并进一步阐明它们在大脑的生理和病理学中的作用。 公共卫生相关性：离子渠道是大脑的晶体管，因此控制了从我们的感官到思想的一切。超极化激活的循环核苷酸门控（HCN）通道从根本上参与了我们大脑中神经元的电兴奋性，并且它们的功能障碍负责某些神经系统疾病（例如癫痫）。我们的长期目标是了解HCN通道如何控制神经元兴奋性的分子机制，使我们能够开发针对神经系统疾病的靶向疗法。