Gating Mechanisms of Retinal Cyclic Nucleotide-Regulated Ion Channels

视网膜环状核苷酸调节离子通道的门控机制

• 批准号: 8694326
• 负责人: Stefan Stoll
• 金额: $ 50.14万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-01-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8694326
• 关键词: Agonist; Behavior; Binding; Brain; C-terminal; Cardiac; Cartoons; Cations; Cells; Complex; Cyclic AMP; Cyclic Nucleotides; Cysteine; Cytoplasmic Protein; DNA Sequence Rearrangement; Dendrites; Dependence; Disease; Distal; Electrons; Exhibits; Fluorescence; Fluorescence Resonance Energy Transfer; Fluorometry; Funding; Gated Ion Channel; Goals; Heart; Ion Channel; Ions; Label; Lead; Light; Location; Magnetic Resonance; Measures; Membrane; Metals; Methods; Modeling; Molecular; Neurons; Peptides; Photoreceptors; Play; Property; Protein Binding; Protein Isoforms; RNA Splicing; Regulation; Rest; Retina; Retinal; Roentgen Rays; Role; Shapes; Signal Transduction; Structure; Surface; Synapses; Testing; Transition Elements; Visual; base; molecular dynamics; molecular rearrangement; patch clamp; public health relevance; research study; response; therapy design; trafficking; voltage

Abstract Hyperpolarization-activated cyclic nucleotide-modulated (HCN) ion channels were first discovered in photoreceptors where they shape the light response. They exhibit several properties that make them specialized for retinal signaling: 1) they are activated by membrane hyperpolarization instead of depolarization, 2) they are regulated by the direct binding of cyclic nucleotides to an intracellular domain, and 3) they are expressed in the distal dendrites of neurons. Recently an accessory subunit of HCN channels in photoreceptors and other neurons was discovered, called TRIP8b, that has a profound effect on each of these important channel properties. Our long term goal is to understand the molecular mechanisms for these properties. In previous funding periods we have made great progress toward achieving this goal. We have solved the X-ray crystal structure of the cyclic nucleotide-binding domain of HCN2 and the structure of TRIP8b bound to HCN2. We have also invented three ground-breaking new fluorescence methods that allow us to record molecular rearrangements in intact channels simultaneous with electrophysiological recording. In this funding period, we propose to combine these methods with double electron-electron resonance (DEER), a powerful magnetic resonance-based method, and molecular dynamics simulations, to measure and model the structure and dynamics of the HCN channel and its interaction with TRIP8b. These experiments will lead to the first dynamic picture for how HCN channels regulate the excitability of photoreceptors and other neurons.

摘要