Structural Basis of “Force from Lipids” Activation in Mechanosensitive Channels

机械敏感通道中“脂质力”激活的结构基础

• 批准号: 10216309
• 负责人: Eduardo A Perozo
• 金额: $ 35.64万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10216309
• 关键词: Address; Antibiotics; Archaea; Architecture; Automobile Driving; Bacteria; Behavior; Biological; Biomedical Engineering; Cells; Communication; Computing Methodologies; Coupling; Cryoelectron Microscopy; Crystallization; Data; Data Set; Detergents; Development; Disease; Drug Delivery Systems; Elements; Environment; Event; Family; Goals; Growth; Health; Hearing; Heterogeneity; Hydrophobicity; Ion Channel; Ion Channel Gating; Libraries; Light; Lipid Bilayers; Lipids; Location; Mechanics; Membrane; Membrane Proteins; Methods; Modeling; Molecular; Molecular Conformation; Motion; Mutagenesis; Mutation; N-terminal; Nature; Nociception; Organism; Orthologous Gene; Osmoregulation; Pathway interactions; Pattern; Physiological; Physiological Processes; Plants; Play; Population; Positioning Attribute; Prokaryotic Cells; Proprioception; Proteins; Resolution; Roentgen Rays; Role; Sensory; Signal Transduction; Spin Labels; Stimulus; Structure; System; Thermodynamics; Thick; Touch sensation; base; deep sequencing; design; experience; extracellular; fascinate; feasibility research; gain of function; interfacial; mechanotransduction; member; monolayer; mutant; nanodisk; next generation sequencing; novel; particle; patch clamp; physical property; physical state; protein function; reconstitution; response; vapor

Project Summary/Abstract Mechanosensitive (MS) channels are oligomeric membrane proteins that function as mechano-electrical sensory switches in a wide range physiological processes. These include touch, hearing, proprioception, turgor control in plant cells and osmoregulation in bacteria. Among these, a fundamental class of MS channels responds to changes in the physical properties of the lipid bilayer by undergoing major structural transitions in response to membrane tension, thus fulfilling a major role in the response of living organisms to mechanical stimuli. This has been referred to as the “force from lipid” principle of mechanosensitivity. The overall, long-term goal of this project is to understand the molecular mechanism of “force from lipid” gating in mechanosensitive channels. Specifically, we will focus on the MscS family of MS channels found in most prokaryotes and plants. These channels are of fundamental importance in various physiological events, can been engineered for biomedical applications, and display fascinating intramembrane heterogeneity among family orthologs. More importantly, the MscS family Affords us the possibility of studying the functional behavior, high resolution structure and dynamics in the same MS system. Although MscL and MscS channels have been studied extensively and crystal structures have been available in multiple conformations, there are still major mechanistic questions that remain to be solved. This is particularly true for the molecular events underlying channel gating, in light of exciting new preliminary data at the core of this proposal. In this respect, we plan to experimentally address several fundamental questions: What is the physical basis of the energy transduction steps, starting with trans-bilayer tension and culminating in protein motion? What are the structures of the key functional states in its native, bilayer-embedded form? Where in the molecule does mechanical transduction occur? And how? Functional studies will be designed to understand the physical basis of energy transduction. Information on the architecture, dynamics and energetic relationship of MscS (plus other related members of the superfamily) with its surrounding lipid bilayer will be obtained from cryo-EM, EPR analysis of spin labeled mutants and computational methods. The data will be interpreted to generate high resolution structures of the different stages of the gating pathway in each type of channel. We suggest that the advent of new cryo-EM approaches to the analysis of structure and dynamics in membrane proteins in their native environment shall open an exciting new experimental avenue that will contribute to the understanding of biologically important events such as ion channel gating, nociception and signal transduction.

项目概要/摘要 机械敏感 (MS) 通道是寡聚膜蛋白，具有机电功能 各种生理过程中的感觉开关，包括触觉、听觉、本体感觉、膨压。 其中，一类基本的 MS 通道。 通过经历主要的结构转变来响应脂双层物理性质的变化 对膜张力的响应，从而在生物体对机械的响应中发挥重要作用 这被称为机械敏感性的“脂质力”原理。 该项目的总体、长期目标是了解“脂质力”的分子机制 具体来说，我们将重点关注 MS 通道中的 MScS 系列。 大多数原核生物和植物在各种生理事件中都具有重要意义。 可以被设计用于生物医学应用，并显示出令人着迷的膜内异质性 更重要的是，MscS家族为我们提供了研究功能的可能性。 同一 MS 系统中的行为、高分辨率结构和动力学。 尽管主要研究了MscL和MscS通道并且晶体结构已经被研究 尽管有多种构象，但仍有一些重大的机制问题有待解决。 鉴于令人兴奋的新初步数据，对于通道门控背后的分子事件尤其如此 在这方面，我们计划通过实验解决几个基本问​​题： 能量转换步骤的物理基础是什么，从跨双层张力开始到最终 蛋白质运动中的关键功能状态的结构是什么？ 机械传导在分子的什么位置发生？又是如何发生的？ 功能研究旨在了解能量转换信息的物理基础。 关于 MscS 的架构、动力学和能量关系（以及该组织的其他相关成员） 超家族）及其周围的脂质双层将通过冷冻电镜、自旋标记的 EPR 分析获得 突变体和计算方法将被解释以生成高分辨率的结构。 每种类型通道中门控途径的不同阶段我们建议新冷冻电镜的出现。 分析膜蛋白在其天然环境中的结构和动力学的方法应 开辟一条令人兴奋的新实验途径，这将有助于理解具有重要生物学意义的东西 离子通道门控、伤害感受和信号转导等事件。