ORGANIZATION OF ACTIN-MYOSIN-II NETWORK IN CLEAVAGE FURROW OF DICTYOSTELIUM CELL

网柄细胞分裂沟中肌动蛋白-肌球蛋白-II网络的组织

• 批准号: 7722844
• 负责人: Douglas Robinson
• 金额: $ 0.92万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7722844
• 关键词: Actins; Cell Shape; Cell division; Cells; Computer Retrieval of Information on Scientific Projects Database; Cytokinesis; Dictyostelium; Formvar 1285; Freeze Substitution; Freezing; Funding; Goals; Gold; Grant; Institution; Microfilaments; Mitotic; Modeling; Molecular; Myosin ATPase; Myosin Type II; Organism; Plastics; Process; Research; Research Personnel; Resolution; Resources; Source; Staging; Textbooks; Thick Filament; United States National Institutes of Health; Work; cell type; cellular imaging; mutant; reconstruction

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The objective of this project is to acquire 3D structural information about the organization of the actin-myosin-II network in the cleavage furrow cortex of Dictyostelium cells at different stages f furrow ingression. In our work, we have been developing a quantitative framework for cytokinesis in order to understand the molecular mechanisms that govern the dynamics of cell shape change. Myosin-II and actin are central to this process. Many textbook models of cytokinesis invoke a circumferential belt of actin filaments with the myosin-II thick filaments arranged so that the cleavage furrow is constricted like a purse string. While this organization is likely to be correct for some organisms, several lines of evidence challenge this as a general framework. First, myosin-II mutant Dictyostelium cells undergo mitotic cell division nearly as fast as wild-type cells. Second, Dictyostelium myosin-II is kinetically tuned and assembled into thick filaments in such a way as to make it difficult to conceptualize a simple sarcomeric-like contraction mechanism; some mammalian nonmuscle myosin-IIs are similarly tuned. Third, in mammalian and Dictyostelium, cells, a clear ring of actin filaments is not clearly detectable. High resolution structural information would allow us to considerably refine our current models for cytokinesis in Dictyostelium. The initial goal of this project is to determine the orientation of actin filaments and myosin-II thick filaments at various stages of furrow ingression. We have prepared cells by rapidly plunge freezing formvar-coated gold EM grids with attached cells and are imaging these for tomographic reconstruction both as whole mounts in the frozen-hydrated state and as plastic sections after freeze-substitution.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 该项目的目的是在不同阶段的裂解阶段的裂解沟皮层中获取有关肌动蛋白 - 肌球蛋白-II网络组织的3D结构信息。在我们的工作中，我们一直在为细胞因子的定量框架开发，以了解控制细胞形状动力学变化的分子机制。肌球蛋白-II和肌动蛋白是这一过程的核心。许多细胞因子的教科书模型带有肌动蛋白丝的圆周带，并与肌球蛋白-II厚细丝排列，以使裂解沟像钱包一样被限制。尽管该组织对于某些生物体可能是正确的，但有几条证据作为一般框架挑战这一点。首先，肌球蛋白-II突变体柱状骨细胞经历有丝分裂细胞分裂几乎与野生型细胞一样快。其次，将肌球蛋白-II进行了动力学调节并组装成厚的细丝，以使很难概念化一种简单的肉瘤样收缩机制。某些哺乳动物的非肌肉肌球蛋白 - 同样调整了。第三，在哺乳动物和dictyostelium中，细胞，无法清楚地检测到肌动蛋白丝的透明环。高分辨率的结构信息将使我们能够大大完善当前在dictyostelium中的细胞因子模型。该项目的最初目标是确定肌动蛋白丝和肌动蛋白-II厚细丝的方向。我们通过与附着的细胞迅速融化形式的金色EM网格，制备了细胞，并将其成像以进行层析成像重建，因为整个安装在冷冻水合状态下，又是冻结固定后的塑料部分。