Thin Filaments and Muscle Regulation

细丝和肌肉调节

• 批准号: 8605902
• 负责人: WILLIAM J LEHMAN
• 金额: $ 40.11万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-09-30 至 2017-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8605902
• 关键词: Actin-Binding Protein; Actins; Address; Architecture; Asthma; Attention; Binding; Binding Proteins; Binding Sites; Blood Vessels; Cardiac; Cardiac Muscle Contraction; Cardiomyopathies; Cardiovascular Diseases; Cardiovascular system; Chemicals; Computational Biology; Coupled; Data; Development; Disease; Electrons; Filament; Functional disorder; Goals; Hypertension; Image Analysis; Inherited; Lead; Link; Lung; Lung diseases; Microfilaments; Molecular; Molecular Structure; Movement; Muscle; Muscle Contraction; Mutation; Myocardium; Myosin ATPase; Participant; Process; Protein Dynamics; Proteins; Protocols documentation; Regulation; Resistance; Resolution; Respiration Disorders; Skeletal Muscle; Smooth Muscle; Structure; System; Techniques; Testing; Thin Filament; Tropomyosin; Troponin; Work; base; computerized tools; design; genetic regulatory protein; innovation; link protein; molecular dynamics; mutant; myosin-binding protein C; particle; reconstruction; structural biology; therapeutic target

Thin filament-linked actin-binding proteins control both actomyosln-based muscle contraction and cytoskeletal formation. In order to understand the normal control of muscle contraction, it is crucial to characterize the structural interactions of thin filament regulatory proteins that influence actin-mvosin association. Using structural analysis, we will examine the architecture of cardiac and skeletal muscle thin filaments at a fundamental level and determine the changing interactions of thin filament-linked proteins that regulate muscle activity. Our principal objective therefore is to solve the atomic structure of the entire thin filament in relaxed and in active muscle. We use state-of-the-art electron microscopv and electron tomographv. coupled with image analysis, 3D reconstruction (3DEM) and computational ehemistrv to establish the macromolecular structure of actin-binding proteins on thin filament actin and thus demarcate molecular contacts of binding proteins with actin at near atomic resolution. Using these techniques: (1) We aim to detennine the structural basis of troponin-tropomyosin regulation of cardiac and skeletal muscle activity by analyzing interactions of tropomyosin and troponin on thin filaments, which are governed by Ca^^-binding to troponin and myosin-crossbridge binding on actin. To accomplish this goal, (a) we will describe the complete atomic structure of tropomyosin and troponintropomyosin on thin filaments by generating single particle and electron tomographic reconstructions at increasingly high resolution and by fitting atomic resolution crystal structures of actin and regulatory proteins into the reconstruction volumes; (b) we will further refine these atomic structures using computational tools to maximize chemical interactions between regulatory proteins and actin; (c) we will use Molecular Dynamics protocols to assess regulatory protein dynamics and likely transitions between regulatory states. (2) Using this same approach, we will test the hypothesis that mutant cardiac troponin and tropomyosin perturb muscle regulation by causing imbalanced protein interactions that alter the regulatory state of thin filaments, and we will determine the underlying structural reasons for such perturbations. (3) We will test the hypothesis that the short molecular overlap domain between adjacent tropomyosins, needed for end-to-end tropomyosin linkage, is vital for tropomyosin strand formation on filaments, and again assess the impact of mutants on this structure. (4) We will complete efforts to test the hypothesis that Myosin-Binding Protein C forms regular and periodic links to thin filaments, which are likely to modulate striated contractile activity.

细丝连接肌动蛋白结合蛋白控制基于肌动肌液的肌肉收缩和 细胞骨架形成。为了理解肌肉收缩的正常控制，这对 表征影响肌动蛋白 - 伏蛋白的细丝调节蛋白的结构相互作用 协会。使用结构分析，我们将检查心脏和骨骼肌的结构 细丝在基本水平上，并确定细丝连接的变化相互作用 调节肌肉活性的蛋白质。因此，我们的主要目标是解决原子 放松和活跃肌肉中整个细丝的结构。我们使用最先进的 电子显微镜和电子断层牙条。结合图像分析，3D重建（3DEM） 和计算eHemistrv以在肌动蛋白结合蛋白上建立大分子结构 薄丝细丝肌动蛋白，从而划定结合蛋白与肌动蛋白在近原子上的分子接触 解决。使用这些技术：（1）我们旨在确定肌钙蛋白 - 肌球蛋白的结构基础 通过分析肌球蛋白和肌钙蛋白的相互作用来调节心脏和骨骼肌活性 在薄丝上，由Ca ^^ - 与肌动蛋白结合的肌动蛋白结合和肌动蛋白结合。 为了实现这一目标，（a）我们将描述肌球蛋白和肌动毒素的完整原子结构 通过在薄丝上产生单个粒子和电子断层造影重建 分辨率越来越高，并通过拟合肌动蛋白和调节蛋白的原子分辨率晶体结构 进入重建量； （b）我们将使用计算工具进一步完善这些原子结构 最大化调节蛋白与肌动蛋白之间的化学相互作用； （c）我们将使用分子 评估调节蛋白动力学和调节状态之间可能过渡的动力方案。 （2）使用这种方法，我们将检验以下假设：突变心脏肌钙蛋白和肌动球蛋白 通过引起不平衡蛋白质相互作用来改变薄的调节状态，从而扰动肌肉调节 细丝，我们将确定这种扰动的根本结构原因。 （3）我们将测试 假设端到端所需的相邻肌动蛋白之间的短分子重叠结构域 tropomyosin链接，对于肌球蛋白链对细丝至关重要，并再次评估 这种结构上的突变体。 （4）我们将完成测试肌球蛋白结合蛋白C的假设 形成与细丝的常规和周期性联系，可能会调节条纹的收缩活动。