Molecular mechanisms of cell shape change in cytokinesis

胞质分裂过程中细胞形状变化的分子机制

• 批准号: 8348652
• 负责人: Amy Shaub Maddox
• 金额: $ 16.93万
• 依托单位: UNIVERSITY OF MONTREAL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-21 至 2013-07-01
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8348652
• 关键词: Accounting; Actins; Actomyosin; Adverse effects; Aneuploidy; Animal Model; Antineoplastic Agents; Apoptosis; Behavior; Biological Assay; Biological Models; Biomechanics; Bundling; Caenorhabditis elegans; Cell Cycle Proteins; Cell Shape; Cell division; Cell membrane; Cells; Chimeric Proteins; Clinic; Collaborations; Complex; Computer Simulation; Coupled; Cytokinesis; Cytoskeletal Filaments; Cytoskeleton; Data; Development; Drug Delivery Systems; Event; F-Actin; Failure; Feedback; Filament; Gastrointestinal tract structure; Goals; Human body; Image Analysis; Interphase Cell; Kinetics; Laboratories; Life; Malignant Neoplasms; Mammals; Measures; Mechanics; Membrane; Methods; Mitotic; Modeling; Molecular; Mothers; Myosin ATPase; Nature; Organelles; Pathology; Persons; Pharmaceutical Preparations; Phylogeny; Positioning Attribute; Process; Proteins; Quantitative Microscopy; Regulation; Role; Shapes; Skin; Slide; Structural Protein; Tetraploidy; Time; Tissues; Uncertainty; United States National Institutes of Health; Work; base; cancer cell; constriction; daughter cell; innovation; insight; interdisciplinary approach; novel; protein function; single molecule; success; tumor; zygote

Cytokinesis, the physical division of one cell into two, is accomplished by a transient organelle called the contractile ring. The PI is focused on the molecular and biophysical mechanisms of contractile ring function. Ongoing work in the PI's laboratory has yielded an explanation of asymmetric (non-concentric) ring closure, which is seen throughout metazoa. To explain this asymmetry, a biomechanical feedback loop was proposed, among cytoskeletal filament alignment, filament sliding, and membrane curvature. An in silico model based on this feedback can recapitulate ring closure asymmetry, as well as the kinetics of closure initiation and duration in the C. elegans zygote, the primary animal model for this work. To expand and strengthen this model, the proposed work aims to define the molecular and physical mechanisms of each component of the feedback loop. Specifically, the conserved proteins that contribute to alignment of cytoskeletal filaments with each other and with the membrane will be defined. The existence of myosin in the form of bipolar minifilaments in the contractile ring will be defined. Last, the shape of the cell throughout cytokinesis will be described and correlated with local protein enrichment and organization. The proposal centers on the use of three dimensional live-cell (time-lapse) microscopy and quantitative image analysis. Several novel quantitative assays for contractile ring assembly, organization and function will be used. These include ways to measure F-actin alignment, kinetics and position of ring closure throughout cytokinesis, the number of molecules in macromolecular cortical complexes, and the three-dimensional shape of the cell during the course of division. The C. elegans zygote serves as an ideal model system for these studies due to its reproducible size, shape, and the kinetics of cell division events, the ease of thorough depletion of essential proteins, the ability to examine the first cell division attempted following protein depletion, and the availability of strains stably expressing fluorescent fusion proteins that serve as markers for various subcellular components and compartments. Importantly, cell cycle regulatory and structural proteins are conserved among C. elegans and mammals. The long-term goal of this work is to aid the development of anti-cancer chemotherapeutics that block cytokinesis. Targeting proteins that act specifically in the contractile ring should avoid the side effects on non-dividing cells of many popular drugs. In addition, because currently used anti-mitotics also have limited success against some tumor types, development of cytokinesis drugs will be a welcome expansion and diversification of our arsenal against cancers.

细胞分裂，即一个细胞一分为二的物理分裂，是通过短暂的过程完成的 细胞器称为收缩环。 PI 专注于分子和生物物理 收缩环功能的机制。 PI 实验室正在进行的工作已经取得了成果 对不对称（非同心）环闭合的解释，这在整个后生动物中都可见。到 为了解释这种不对称性，提出了细胞骨架之间的生物力学反馈回路 细丝排列、细丝滑动和膜曲率。基于此的计算机模型 反馈可以概括环闭合不对称性以及闭合启动的动力学 以及线虫受精卵（这项工作的主要动物模型）中的持续时间。 为了扩展和加强这个模型，拟议的工作旨在定义分子和 反馈环路每个组件的物理机制。具体来说，保守的 有助于细胞骨架丝彼此对齐以及与细胞骨架丝对齐的蛋白质 膜将被定义。肌球蛋白以双极微丝的形式存在 将定义收缩环。最后，整个胞质分裂过程中细胞的形状将是 描述并与局部蛋白质富集和组织相关。 该提案的重点是使用三维活细胞（延时）显微镜和 定量图像分析。用于收缩环组装的几种新颖的定量测定， 将使用组织和功能。其中包括测量 F-肌动蛋白排列的方法， 整个胞质分裂过程中闭环的动力学和位置，分子数量 大分子皮质复合物以及细胞在运动过程中的三维形状 划分的过程。线虫受精卵是这些研究的理想模型系统 由于其可重复的尺寸、形状和细胞分裂事件的动力学，易于彻底 必需蛋白质的耗尽，检查第一次细胞分裂尝试的能力 蛋白质耗尽，以及稳定表达荧光融合蛋白的菌株的可用性 作为各种亚细胞成分和区室的标记。重要的是细胞周期 调节蛋白和结构蛋白在秀丽隐杆线虫和哺乳动物中是保守的。 这项工作的长期目标是帮助抗癌化疗药物的开发 阻断胞质分裂。针对在收缩环中特异性作用的蛋白质应避免 许多流行药物对非分裂细胞的副作用。另外，由于目前使用 抗有丝分裂药物对某些肿瘤类型、胞质分裂的发展也有有限的成功 药物将是我们对抗癌症的武器库的一个值得欢迎的扩展和多样化。