Tropomyosin and the Regulation of Muscle Contraction

原肌球蛋白和肌肉收缩的调节

基本信息

批准号：
7822163
负责人：
SHERWIN LEHRER
金额：
$ 1.18万
依托单位：
BOSTON BIOMEDICAL RESEARCH INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-06-01 至 2010-10-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The broad, long-term objective is to elucidate the molecular details of the regulation of striated muscle contraction by determining how trooping and Ca2+ and myosin, regulate the important tropomyosin-actin interaction. Health Relatedness: The role of each component and their interactions are required to understand the malfunctions associated with certain muscle diseases, e.g., familial hypertrophic cardiomyopathy (FHC) resulting from mutations in Tm, TnT, Tnl and myosin. Tm, in its interaction with actin, plays a key role in determining the equilibria between the 3 states of the muscle thin filament, Blocked, Closed and Open (contraction takes place in the Open state). By interacting with actin and Tm, troponin (assisted by Ca2+) and myosin heads change the equilibrium between the states, thereby turning contraction on and off. Specific Aims: (a) to determine the relationship between the flexibility of Tm on actin and the number of actin subunits activated (the cooperative unit size); to determine the altered regulatory properties of the FHC Tm mutants; (b) to determine the location of the Tnl and TnT components of the Tn complex on the actinTm filament and the changes that take place in shifting between activity states; (c) to determine the changing interactions of the thin filament components in the organized sarcomere. Methods: In addition to characterization of the 3 states in solution with ATPase, binding and kinetic studies, extensive use will be made of high resolution distance measurements between components with time-resolved fluorescence-detected energy transfer (FRET) in solution and in regions of the sarcomere of components exchanged into single myofibrils. These measurements between specific labeled amino acid residues will provide information about the dynamics of the changes between the components involved in the regulatory process.

描述（由申请人提供）：广泛的长期目标是通过确定部队，Ca2+和肌球蛋白如何调节重要的肌动蛋白 - 肌动蛋白相互作用，从而阐明条纹肌肉收缩的分子细节。健康相关性：需要每个成分及其相互作用的作用才能理解与某些肌肉疾病相关的故障，例如TM，TNT，TNL和肌球蛋白中突变引起的家族性肥厚心肌病（FHC）。 TM在与肌动蛋白的相互作用中，在确定肌肉薄丝的3个状态之间的平衡中起着关键作用，阻塞，闭合和开放（收缩发生在开放状态）。通过与肌动蛋白和TM相互作用，肌钙蛋白（由Ca2+）和肌球蛋白头与状态之间的平衡改变，从而改变了和关闭收缩。具体目的：（a）确定TM对肌动蛋白的灵活性与激活的肌动蛋白亚基数（合作单位大小）之间的关系；确定FHC TM突变体的调节特性的改变；（b）确定TN复合物在Actintm细丝上的TNL和TNT成分的位置以及活动状态之间转移时发生的变化；（c）确定有组织的肌膜中细丝成分的相互作用变化。方法：除了用ATPase，结合和动力学研究的溶液中表征3个状态外，还将大量使用在组件之间的高分辨率距离测量以及时间分辨荧光检测的能量转移（FRET）中，在溶液中和溶液中的溶液和肉瘤区域中的组分群体中交换为单个肌动纤维。特定标记的氨基酸残基之间的这些测量将提供有关调节过程中涉及的组件之间变化的动力学信息。