THIN FILAMENTS AND MUSCLE REGULATION

细丝和肌肉调节

• 批准号: 2739330
• 负责人: WILLIAM J LEHMAN
• 金额: $ 26.38万
• 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 2002-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2739330
• 关键词: Rana; actins; animal tissue; caldesmon; calponin; electron microscopy; image processing; microfilaments; muscle contraction; muscle proteins; myocardium; myosin light chain kinase; myosins; protein reconstitution; protein structure function; smooth muscle; striated muscles; tissue /cell culture; tropomyosin; troponin

Thin filament-associated actin-binding proteins have dual function, controlling actomyosin-based contractility and cytoskeletal assembly in a variety of muscle and non-muscle systems. In striated muscles, the regulatory protein complex, troponin-tropomyosin, linked to thin filaments, controls contractility by sterically blocking and unblocking myosin-crossbridge binding on actin in response to changing Ca/2+ levels. In smooth muscle, thin filament-associated caldesmon and calponin may function similarly to modulate actomyosin-based motility and/or the state of cytoskeletal assembly. To accomplish our goal to determine the regulatory mechanisms by which these proteins function in striated and smooth muscles, it is crucial to assess their structural interactions on isolated and reconstituted thin filaments and their respective responses to Ca/2+, myosin-crossbridge binding and phosphorylation. For a fuller picture of filament function, it is also essential to understand the structural interactions of muscle and related non-muscle actin- cytoskeletal proteins State of the art electron microscopy, computer- assisted image analysis and three-dimensional reconstruction will be used to determine the arrangement of thin filament components on F-actin and to evaluate their position and influence on actin domains. Reconstruction will be fitted to the atomic map of F-actin to detail contacts with specific amino acid clusters on actin monomers. Our own published reconstructions and those of our colleagues demonstrate the feasibility of these goals. Our continued structural studies on troponin-tropomyosin regulated filaments will lead to an elucidation of the molecular mechanism of relaxation and activation in skeletal and cardiac muscle. Our studies to smooth muscle filament swill contribute to understanding the fine tuning of the smooth muscle contractile response and the construction of its cytoskeleton. A general understanding of the molecular mechanisms involved in the regulation of contractility in healthy muscle tissue will aid in our evaluation of defects occurring in disease. The control of smooth muscle contractility, for example, is of great importance in the regulation of vascular tone and pulmonary airway resistance, determinants in a number of disease processes such as hypertension and asthma. The wider significance of our goals is underscore by possible participation of caldesmon, calponin and proteins with consensus calponin homology-domains in such diverse cellular processes as cytokinesis, exocytosis, cortical cytoskeleton modeling and signal transduction modulation, i.e. processes that are essential to all normal cells and that can become aberrant in malignancy.

瘦蛋白相关肌动蛋白结合蛋白具有双重功能， 控制基于肌动球蛋白的收缩性和细胞骨架组装， 各种肌肉和非肌肉系统。在横纹肌中， 调节蛋白复合物，肌钙蛋白原肌球蛋白，连接到薄 纤维，通过空间阻断和解除阻断来控制收缩性 肌动蛋白上的肌球蛋白-交联桥结合对变化的Ca/2+水平的反应。 在平滑肌中，与平滑肌细胞相关的钙调素和钙调蛋白可能 类似地调节基于肌动球蛋白的运动性和/或状态 细胞骨架组装的过程。为了实现我们的目标， 这些蛋白质在横纹肌和 平滑肌，这是至关重要的，以评估其结构上的相互作用， 分离的和重组的细丝及其各自的响应 对Ca/2+、肌球蛋白-交联桥结合和磷酸化的影响。为了更全面 图灯丝功能，它也是必不可少的了解 肌肉和相关非肌肉肌动蛋白的结构相互作用- 细胞骨架蛋白质最先进的电子显微镜，计算机- 将使用辅助图像分析和三维重建 确定F-肌动蛋白上细丝组分的排列， 评估其位置和对肌动蛋白结构域的影响。重建 将适合F-肌动蛋白的原子图，以详细说明与 肌动蛋白单体上的特定氨基酸簇。我们自己出版的 重建和我们的同事证明的可行性， 这些目标。我们对肌钙蛋白-原肌球蛋白结构的继续研究 调控丝将导致阐明的分子机制 骨骼肌和心肌的松弛和激活。我们的研究 平滑肌细丝的研究将有助于理解 调节平滑肌收缩反应和构建 细胞骨架对分子机制的一般理解 参与调节健康肌肉组织的收缩性， 帮助我们评估疾病中出现的缺陷。的控制 平滑肌收缩性，例如，是非常重要的， 调节血管张力和肺气道阻力，决定因素 在许多疾病过程中，如高血压和哮喘。的 我们目标的更广泛意义由于可能有 钙调素、钙调蛋白和具有共有钙调蛋白同源结构域的蛋白质 在胞质分裂、胞吐、皮质 细胞骨架建模和信号转导调节，即过程 对所有正常细胞都是必需的， 恶性肿瘤