Regulation of actin dynamics during myofibril assembly

肌原纤维组装过程中肌动蛋白动力学的调节

• 批准号: 7477731
• 负责人: Shoichiro Ono
• 金额: $ 32.24万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7477731
• 关键词: Actin-Binding Protein; Actins; Biochemical; Biochemical Genetics; Caenorhabditis elegans; Cell physiology; Cytoskeleton; Development; Enhancers; Equilibrium; F-actin-binding proteins; Filament; Immunoglobulins; Length; Maintenance; Microfilaments; Muscle; Muscle Cells; Myofibrils; Nemaline Myopathies; Nematoda; Numbers; Pathogenesis; Protein Isoforms; Proteins; Rate; Recycling; Regulation; Research Personnel; Striated Muscles; Structure; Thin Filament; Tropomyosin; actin depolymerizing factor; actin interacting protein 1; calponin; cofilin; depolymerization; monomer; polymerization; profilin; programs; protein function

DESCRIPTION (provided by applicant): The actin cytoskeleton is adapted to many different structures and involved in diverse cellular functions. Differentiation of the cytoskeletal structures is generally controlled by a number of actin-binding proteins that regulate dynamics and organization of the actin filaments. Myofibrils in striated muscle are highly differentiated forms of the actin cytoskeleton and specialized for generating contractile forces. However, the mechanisms by which actin filaments are assembled into myofibrils during development and maintained in the contractile apparatuses are largely unknown. The nematode Caenorhabditis elegans has obliquely striated muscle in the body wall, which shares a number of biochemical and functional similarities with vertebrate striated muscle. We have identified actin depolymerizing factor (ADF)/cofilin, actin-interacting protein 1 (AIP1), and tropomyosin as key regulators of actin organization in the body wall muscle. When these proteins are defective, the actin filaments are disorganized and the contractility of the body wall muscle is impaired. In addition, we obtained evidence that UNC-87, a calponin-like protein, and kettin, immunoglobulin-like repeat protein, may stabilize actin filaments, and PFN-3, a muscle-specific profilin, may help recycling actin monomers for polymerization. Although genetic and biochemical analyses of these proteins suggest that each of these actin-binding proteins might be important for regulation of actin dynamics in muscle cells, we do not understand how these proteins functionally interact. We hypothesize that ADF/cofilin is a key enhancer of actin dynamics and functionally interacts with other actin-binding proteins to regulate actin polymerization, depolymerization, and stability during assembly and maintenance of the striated myofibrils. In this project, we aim to investigate mechanisms of three aspects of actin dynamics in muscle cells in C. elegans: (Aim 1) To determine how ADF/cofilin and AIP1 disassemble actin filaments in muscle cells, (Aim 2) To determine how actin monomers are recycled for polymerization in muscle cells, and (Aim 3) To determine how actin filaments are stabilized in muscle cells. These studies should provide important information not only on the mechanism of normal myofibril assembly and maintenance but also on the pathogenesis of nemaline myopathy in which misregulation of actin filament stability is implicated.

描述（由申请人提供）：肌动蛋白细胞骨架适应于许多不同的结构，并参与多种细胞功能。细胞骨架结构的分化通常由许多肌动蛋白结合蛋白控制，这些肌动蛋白结合蛋白调节肌动蛋白丝的动力学和组织。横纹肌中的肌原纤维是肌动蛋白细胞骨架的高度分化形式，专门用于产生收缩力。然而，肌动蛋白丝在发育过程中组装成肌原纤维并维持在收缩器官中的机制在很大程度上是未知的。秀丽隐杆线虫的体壁上有斜横纹肌，它与脊椎动物的横纹肌有许多生化和功能上的相似之处。我们已经确定了肌动蛋白解聚因子（ADF）/cofilin，肌动蛋白相互作用蛋白1（AIP 1），原肌球蛋白作为在体壁肌肉肌动蛋白组织的关键调节因子。当这些蛋白质有缺陷时，肌动蛋白丝就会紊乱，体壁肌肉的收缩力就会受损。此外，我们还获得了证据表明，钙调蛋白样蛋白P10 -87和免疫球蛋白样重复蛋白Kettin可以稳定肌动蛋白丝，而肌肉特异性profilin PFN-3可以帮助回收肌动蛋白单体进行聚合。虽然这些蛋白质的遗传和生物化学分析表明，这些肌动蛋白结合蛋白可能是重要的肌肉细胞中的肌动蛋白动力学的调节，我们不知道这些蛋白质的功能如何相互作用。我们假设ADF/cofilin是肌动蛋白动力学的关键增强子，并且在功能上与其他肌动蛋白结合蛋白相互作用以调节肌动蛋白聚合、解聚和在横纹肌原纤维的组装和维持期间的稳定性。本研究旨在探讨C.优雅：（目的1）确定ADF/cofilin和AIP 1如何分解肌细胞中的肌动蛋白丝，（目的2）确定肌动蛋白单体如何在肌细胞中再循环用于聚合，以及（目的3）确定肌动蛋白丝如何在肌细胞中稳定。这些研究不仅提供了重要的信息，正常的肌原纤维组装和维护的机制，但也对线虫肌病的发病机制，其中涉及的肌动蛋白丝稳定性失调。