Tropomyosin-regulated actomyosin-based contractility in nonmuscles cells

非肌肉细胞中原肌球蛋白调节的基于肌动球蛋白的收缩性

• 批准号: 268184046
• 负责人: Professor Dr. Dietmar J. Manstein
• 金额: --
• 依托单位: Institut für Biophysikalische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/268184046?language=en
• 关键词: Tropomyosin; regulated; actomyosin; based; contractility

Our goal is the elucidation of mechanisms that govern tropomyosin-regulated actomyosin-based contractility in nonmuscle cells. Tropomyosin-binding to bare actin filaments has been described with the notion gestalt-binding. However, gestalt-binding is easily disrupted by other actin-binding proteins and fails to provide a satisfactory explanation for the role of low molecular weight isoforms of tropomyosin in the formation of functionally distinct filament populations, which display well-defined isoform-composition and function. Our work is based on a model where NM-2 isoforms are required in addition to cytosolic actin and Tm isoforms to establish minimal functional entities with clearly defined properties. Myosin mediates all stereospecific interactions in the resulting ATmM complex, thereby enhancing the specificity of interactions between the individual actin, myosin, and tropomyosin isoforms that coexist in the human cells. The cyclic ATP-dependent interaction of myosin with actin and the production of force and movement support the formation of structurally distinct filament populations. Moreover, we presume that myosin motor activity enhances the dynamic nature of the resulting filament populations, their ability to fulfill a specific functional role, and their independent regulation in different regions of the cell. The thousands of potential combinations of splice isoforms and mutants are a particular challenge in performing this project. Based on our preliminary work, it appears likely that studies with a relatively small number of isoform combinations are sufficient to make accurate predictions about the most common ATmM complexes found in human cells. The availability of the individual rate and equilibrium constants for prototypic cytoskeletal complexes will greatly advance the field, as current modeling approaches are rather inaccurately based on a small number of studies performed with skeletal muscle alpha-actin. Reconstitution and detailed structural characterization of prototypic ATmM complexes promises to reveal insights in the code that defines structure-function relationships in Tm-regulated actomyosin-based contraction, membrane shaping and remodeling, and the integration of cellular signaling events.

我们的目标是阐明机制，管理原肌球蛋白调节肌动球蛋白为基础的收缩在非肌肉细胞。原肌球蛋白与裸肌动蛋白丝的结合被称为完形结合。然而，孕结合很容易被其他肌动蛋白结合蛋白破坏，并未能提供一个令人满意的解释的作用，低分子量的异构体的原肌球蛋白在形成功能不同的细丝人口，显示定义明确的异构体组成和功能。我们的工作是基于一个模型，其中NM-2亚型需要除了细胞溶质肌动蛋白和Tm亚型，以建立最小的功能实体，明确定义的属性。肌球蛋白介导所产生的ATmM复合物中的所有立体特异性相互作用，从而增强共存于人类细胞中的个体肌动蛋白、肌球蛋白和原肌球蛋白亚型之间相互作用的特异性。肌球蛋白与肌动蛋白的环状ATP依赖性相互作用以及力和运动的产生支持结构上不同的肌丝群体的形成。此外，我们推测肌球蛋白运动活性增强了所产生的肌丝群体的动态性质，它们履行特定功能作用的能力，以及它们在细胞不同区域的独立调节。数千种潜在的剪接异构体和突变体的组合是执行该项目的一个特殊挑战。基于我们的初步工作，似乎有可能，研究与相对较少的异构体组合是足以作出准确的预测，最常见的ATmM复合物中发现的人类细胞。原型细胞骨架复合物的个体速率和平衡常数的可用性将大大推进该领域，因为目前的建模方法是相当不准确的基础上进行的骨骼肌α-肌动蛋白的研究数量很少。原型ATmM复合物的重建和详细的结构表征有望揭示在Tm调节的肌动球蛋白为基础的收缩，膜成形和重塑，以及细胞信号事件的整合中定义结构-功能关系的代码中的见解。

项目成果

Thrombocytopenia Microcephaly Syndrome - a novel phenotype associated with ACTB mutations

• DOI: 10.1101/303909
• 发表时间: 2018-04
• 期刊: bioRxiv
• 作者: Sharissa L. Latham;Nadja Ehmke;P. Reinke;M. Taft;M. Lyons;M. Friez;Jennifer A. Lee;Ramona Hecker;M. Frühwald;K. Becker;T. Neuhann;D. Horn;E. Schrock;Katharina Sarnow;Konrad Grützmann;Luzie Gawehn;B. Klink;A. Rump;C. Chaponnier;R. Knöfler;D. Manstein;N. Di Donato

Cryo-EM structure of a human cytoplasmic actomyosin complex at near-atomic resolution

• DOI: 10.1038/nature18295
• 发表时间: 2016-06-30
• 期刊: NATURE
• 影响因子: 64.8
• 作者: von der Ecken, Julian;Heissler, Sarah M.;Raunser, Stefan
• 通讯作者: Raunser, Stefan