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.

细丝相关的肌动蛋白结合蛋白具有双重功能， 控制基于肌动蛋白的收缩力和细胞骨架组件 各种肌肉和非肌肉系统。在条纹的肌肉中 调节性蛋白质复合物，肌钙蛋白 - 肌球蛋白，与薄有关 细丝，通过在空间阻塞和解阻来控制收缩性 肌球蛋白 - 十字桥对肌动蛋白的结合，以响应变化的Ca/2+水平。 在平滑肌中，与细丝相关的Caldesmon和Calponin可能 功能类似于调节基于肌动蛋白的运动性和/或状态 细胞骨架组件的。实现我们的目标来确定 这些蛋白质在条纹和 光滑的肌肉，评估其结构相互作用至关重要 孤立和重构的细丝及其各自的反应 至CA/2+，肌球蛋白 - 骨桥结合和磷酸化。为了饱满 细丝功能的图片，也必须了解 肌肉和相关非肌肉肌动蛋白的结构相互作用 - ART电子显微镜的细胞骨架蛋白质状态，计算机 - 将使用辅助图像分析和三维重建 确定薄丝成分在F-肌动蛋白上的排列和 评估其对肌动蛋白领域的地位和影响。重建 将安装在F-肌动蛋白的原子图上，以详细介绍与 肌动蛋白单体上的特定氨基酸簇。我们自己的出版 重建和我们同事的重建证明了 这些目标。我们对肌钙蛋白 - 肌球蛋白的持续结构研究 受调节的细丝将导致分子机制的阐明 骨骼和心肌的放松和激活。我们的研究 为了平滑肌肉丝扫有助于理解罚款 调整平滑肌收缩反应和构建 它的细胞骨架。对分子机制的一般理解 参与健康肌肉组织中收缩力的调节将 有助于我们评估疾病中发生的缺陷。控制 例如，平滑肌收缩力在 调节血管张力和肺气道耐药性，决定因素 在许多疾病过程中，例如高血压和哮喘。这 我们的目标的更广泛意义是通过可能参与的 Caldesmon，Calponin和蛋白质具有共识CALPONIN同源性疾病 在诸如细胞因子，胞吐作用，皮质等多种细胞过程中 细胞骨架建模和信号转导调制，即过程 对于所有正常细胞来说都是必不可少的，在 恶性。