Structural Studies of Actin

肌动蛋白的结构研究

• 批准号: 7457967
• 负责人: EDWARD H. EGELMAN
• 金额: $ 34.43万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-12-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7457967
• 关键词: Actinin; Actins; Actomyosin; Architecture; Area; Bacteriophages; Binding; Binding Proteins; Bundling; Cancer Biology; Cells; Chimera organism; Communicable Diseases; Communities; Complex; Cytoskeleton; Disease; F-Actin; Filament; Fimbrin; Freezing; Funding; G Actin; Gelsolin; Genetic Polymorphism; Higher Order Chromatin Structure; Homologous Gene; Human; Ice; Image; Image Analysis; Indium; Methods; Microfilaments; Modeling; Molecular Conformation; Mothers; Muscle; Muscle Cells; Muscle Contraction; Myosin ATPase; Needles; Neoplasm Metastasis; Numbers; Pathogenesis; Pilum; Play; Process; Productivity; Property; Proteins; Protomer; Range; Regulation; Research; Research Personnel; Resolution; Role; Salmonella; Sampling; Site; Sorting - Cell Movement; Specimen; Spectrin; Striated Muscles; Structure; Takeda brand of pioglitazone hydrochloride; Tertiary Protein Structure; Testing; Thin Filament; Thinking; Toxin; Troponin; Utrophin; Vibrio cholerae; Work; Yeasts; base; calponin; cell motility; computerized tools; crosslink; depolymerization; fundamental research; innovation; insight; interest; link protein; pathogen; plastin; programs; reconstruction; research study; villin

DESCRIPTION (provided by applicant): Actin is the most ubiquitous and conserved eukaryotic protein, and plays a central role in processes from muscle contraction to metastasis to bacterial pathogenesis. As a result, a very large number of other proteins interact with actin. These interactions are important in the nucleation and depolymerization of F-actin, in the bundling of F-actin into higher order structures, and in both muscle and non-muscle motility. We have been actively exploring the multiplicity of structural states within F-actin, as well as investigating the polymorphisms in the binding of many proteins to F-actin. These studies have provided new clues about the basis for extremely conserved actin sequences over large evolutionary distances. We propose to greatly extend our current studies by generating three-dimensional reconstructions of F-actin and complexes between F-actin and other proteins at a significantly higher resolution. This has only become possible recently with new computational tools for the reconstruction of polymorphic and weakly scattering filaments imaged by cryo-EM in ice. These higher resolution reconstructions will illuminate the conformational changes between existing G-actin crystal structures and the protomer within F-actin, as well as give information about how subunit-subunit contacts change as subunits twist and tilt in the filament. We will test the hypothesis that the multiplicity of interactions observed for proteins such as villin, dematin, fimbrin, a-actinin and calponin with F-actin is governed by how the actin filament is nucleated. The rationale for this is that within a cell no actin filaments are self-nucleated, and we and others have shown that nucleating actin with another protein can change the structure of an entire actin filament. We will also gain insights into acto-myosin motility by studying a chimeric actin assembled from both yeast and muscle sequences. The regulation of striated muscle contraction involves the troponin complex on the thin filament, and we will help constrain models of the thin filament by studying a complex of actin with Tnl. Overall, these studies will have a significant impact in areas as diverse as muscle contraction, infectious diseases, and cancer biology.

描述（由申请人提供）：肌动蛋白是最普遍和保守的真核蛋白，并且在从肌肉收缩到转移到细菌发病机理的过程中起着核心作用。结果，许多其他蛋白质与肌动蛋白相互作用。这些相互作用在F-肌动蛋白的成核和解聚，F-肌动蛋白捆绑成高阶结构以及肌肉和非肌肉运动性。我们一直在积极探索F-肌动蛋白内的结构状态的多样性，并研究了许多蛋白质与F-肌动蛋白的结合中的多态性。这些研究为在较大的进化距离上极为保守的肌动蛋白序列的基础提供了新的线索。我们建议以明显更高的分辨率产生F-肌动蛋白和F-肌动蛋白之间的F-肌动蛋白和复合物的三维重建，以极大地扩展我们的目前研究。最近，使用新的计算工具，用于重建冰中的冰冻EM成像的多态性和弱散射丝的新计算工具。这些较高的分辨率重建将阐明现有的G-肌动蛋白晶体结构与F-肌动蛋白中的果实之间的构象变化，并提供有关亚基 - 亚基触点在细丝中的扭曲和倾斜时如何变化的信息。我们将检验以下假设：诸如villin，dematin，fimbrin，a-肌动蛋白和F-肌动蛋白等蛋白质的相互作用的多样性受肌动蛋白丝的成核如何控制。这样做的理由是，在细胞中，没有肌动蛋白丝是自核的，我们和其他人表明，用另一种蛋白质核定肌动蛋白可以改变整个肌动蛋白丝的结构。我们还将通过研究从酵母和肌肉序列组装的嵌合肌动蛋白来了解肌动蛋白肌球蛋白运动。纹状体肌肉收缩的调节涉及薄丝上的肌钙蛋白复合物，我们将通过研究肌动蛋白与TNL的复合物来帮助限制薄丝的模型。总体而言，这些研究将对肌肉收缩，传染病和癌症生物学等多样化的地区产生重大影响。