The UNC-45 Chaperone as a Modulator of Myosin Biogenesis and Function

UNC-45 伴侣作为肌球蛋白生物发生和功能的调节剂

• 批准号: 9477067
• 负责人: GUY Martin BENIAN
• 金额: $ 30.69万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9477067
• 关键词: Address; Amino Acids; Animals; Binding; Biochemical; Biogenesis; Biological; Biological Assay; Biological Models; Biology; Biophysics; CRISPR/Cas technology; Caenorhabditis elegans; Cardiomyopathies; Cell division; Clustered Regularly Interspaced Short Palindromic Repeats; Collaborations; Data; Development; Drosophila genus; Equilibrium; Exposure to; Functional disorder; Genes; Head; Heat Stress Disorders; Heat-Shock Proteins 90; Heat-Shock Response; Hydrogen Peroxide; In Vitro; Investigation; Knowledge; Lead; Length; Mediating; Microfilaments; Molecular; Molecular Chaperones; Molecular Conformation; Motor; Muscle; Muscle Cells; Muscle Development; Muscle function; Mutagenesis; Mutation; Myofibrils; Myopathy; Myosin ATPase; Myosin Type II; Phenotype; Physiological; Process; Protein Isoforms; Proteins; Publishing; Recovery; Regulation; Research; Research Personnel; Role; Sarcomeres; Series; Site; Skeletal Muscle; Stress; Striated Muscles; Structure; System; Techniques; Testing; Thick Filament; Up-Regulation; Vertebrates; Work; cell motility; cell type; crystallinity; developmental disease; experimental study; human disease; in vivo; inhibitor/antagonist; insight; member; multidisciplinary; mutant; non-muscle myosin; novel; novel therapeutic intervention; novel therapeutics; premature; prevent; protein complex; protein folding; public health relevance; recruit; repaired; response; skeletal; stem; temperature sensitive mutant; tumor; tumor progression

 DESCRIPTION (provided by applicant): In this proposal we aim to elucidate the precise molecular mechanisms by which the chaperones UNC-45 and Hsp90 assist in the folding of the myosin head which is critical for sarcomere assembly during development and repair of stress-induced damage to sarcomeres in mature muscle. Developing an understanding of these mechanisms is a problem at the core of muscle development and function. It is also highly relevant to the folding and repair of the many classes of myosin molecules that are expressed in non-muscle tissues. Our recent discovery that myosin attains a novel conformation, which hydrolyzes ATP at the normal rate but with a greatly reduced ability to translocate actin filaments, in the presence of UNC-45 and is reversed by Hsp90, raises important questions as to the exact roles of these chaperones in myosin folding and repair and myofilament assembly. Guided by our recent published and preliminary studies, we hypothesize that during myosin assembly or repair, UNC-45 assists the myosin head to attain its native conformation and subsequently locks it in a state that prevents premature powerstrokes; this state is relieved by Hsp90 upon successful assembly into the sarcomere or repair of myosin heads. This hypothesis will be tested by using a combination of in vitro and in vivo analyses through a unique collaboration between two expert research labs. In Aim 1 we will use mutagenesis, biochemical and biophysical assays, including myosin-dependent actin filament gliding assays, to establish the UNC-45 domains and key amino acid regions that mediate the different unique functions of UNC-45. In Aims 2 and 3 we will use the power of C. elegans as a model system to examine the functional relationships between mutant UNC-45 proteins and sarcomere assembly (Aim 2), and the dynamics of association of UNC-45 and Hsp90 with themselves and with myosin during repair of damaged myosin heads (Aim 3). Our hypothesis, if confirmed, will represent a new paradigm in the biology of myosins, with potential novel therapeutic approaches not only for striated muscle disorders stemming from mutations in sarcomeric proteins (skeletal myopathies and cardiomyopathies), but also for the problem of tumor invasiveness.

 描述（由申请人提供）：在该提案中，我们旨在阐明伴侣蛋白ε 4 -45和Hsp 90协助肌球蛋白头部折叠的精确分子机制，这对于成熟肌肉中肌节的发育和应力诱导损伤的修复过程中的肌节组装至关重要。了解这些机制是肌肉发育和功能的核心问题。它也与非肌肉组织中表达的许多类肌球蛋白分子的折叠和修复高度相关。我们最近的发现，肌球蛋白达到一种新的构象，水解ATP在正常的速度，但大大降低了能力，易位肌动蛋白丝，在存在的β-45和被逆转的热休克蛋白90，提出了重要的问题，这些伴侣蛋白的确切作用，在肌球蛋白折叠和修复和肌丝组装。根据我们最近发表的初步研究，我们假设在肌球蛋白组装或修复过程中，HSP 90 -45帮助肌球蛋白头部达到其天然构象，随后将其锁定在一种防止过早动力中风的状态;这种状态在成功组装成肌节或修复肌球蛋白头部后由HSP 90缓解。这一假设将通过两个专家研究实验室之间的独特合作，使用体外和体内分析的组合进行测试。在目标1中，我们将使用诱变，生物化学和生物物理测定，包括肌球蛋白依赖性肌动蛋白丝滑动测定，以建立介导不同的独特功能的β-45结构域和关键氨基酸区域的β-45。在目标2和3中，我们将使用C的力量。elegans作为一个模型系统，以检查突变的HSP 45蛋白和肌节组装之间的功能关系（目的2），以及HSP 45和HSP 90与自身以及在受损肌球蛋白头修复过程中与肌球蛋白的动态关联（目的3）。我们的假设，如果得到证实，将代表肌球蛋白生物学的一个新的范例，潜在的新的治疗方法，不仅对横纹肌疾病起源于突变的肌节蛋白（骨骼肌病变和心肌病），但也为肿瘤侵袭的问题。