Molecular mechanisms of bundled actin structure assembly by formins

福明组装成束肌动蛋白结构的分子机制

• 批准号: 10216284
• 负责人: Naomi Courtemanche
• 金额: $ 28.65万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2022-12-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10216284
• 关键词: Actins; Address; Affect; Automobile Driving; Binding; Biological; Biological Assay; Biological Process; Biophysics; Bundling; Cell Proliferation; Cell Shape; Cell division; Cell physiology; Cells; Complex; DNA; Development; Diffusion; Dilated Cardiomyopathy; Disease; Equilibrium; Filament; Filopodia; Fluorescence Resonance Energy Transfer; Focal Adhesions; Genes; Growth; In Vitro; Malignant Neoplasms; Mammals; Mediating; Microcephaly; Microfilaments; Modeling; Molecular; Mutation; Nuclear; Play; Polymers; Positioning Attribute; Process; Property; Protein Family; Protein Isoforms; Proteins; Role; Saccharomycetales; Signal Transduction; Stress Fibers; Structure; Techniques; Testing; Thick; Variant; Work; base; cell motility; cofilin; disease-causing mutation; flexibility; human disease; insight; mechanical force; parallel architecture; physical property; polymerization; profilin; scaffold

PROJECT SUMMARY Cells dynamically assemble a diverse set of actin-based structures to perform essential processes including motility, division and signaling. One class of actin structures consists of networks of actin filaments that are bundled together into parallel or anti-parallel architectures. These bundled actin structures include contractile rings, actin cables, filopodia, and the stress fibers that promote focal adhesion maturation and nuclear positioning. The actin filaments that comprise these structures are primarily polymerized by formins, a family of proteins that nucleate and direct the elongation of unbranched actin filaments. Mammals express 15 formin isoforms, each of which possesses unique actin assembly properties and plays a specific role in cells. Although mutations in formin genes are associated with a number of human diseases including preleukemic disorders and cancer, it remains unknown how the polymerization activity of each formin isoform is tuned for the assembly of a specific bundled actin structure and participation in a specific cellular process. To bridge this gap in understanding, we must establish how formins function in the context of the bundled actin structures that exist in cells. We will address this question by characterizing the mechanism of formin-mediated assembly of bundled actin structures. Our central hypothesis is that incorporation of formin-bound actin filaments into bundled structures modulates polymerization by exposing formins to force, filament bundling and filament severing. We will use a combination of biophysical and cell biological approaches to test this hypothesis by pursuing three specific aims: (1) To elucidate the effects of force on the mechanism of formin-mediated filament elongation, (2) to investigate the relationship between filament bundling and formin polymerization activity, and (3) to evaluate the contribution of filament turnover to bundled actin structure assembly. By establishing the mechanism of formin-directed bundled actin assembly, we will gain fundamental insights into the large number of cellular processes regulated by formins. This work will also provide a molecular basis for understanding how formins contribute to healthy cellular proliferation and normal development.

项目概要 细胞动态地组装一组不同的基于肌动蛋白的结构来执行基本过程，包括 运动、分裂和信号传导。一类肌动蛋白结构由肌动蛋白丝网络组成， 捆绑在一起形成并行或反并行架构。这些成束的肌动蛋白结构包括收缩性 环、肌动蛋白线、丝状伪足和促进粘着斑成熟和核的应力纤维 定位。构成这些结构的肌动蛋白丝主要由福明斯（福明斯家族）聚合而成。 使无分支肌动蛋白丝成核并指导其伸长的蛋白质。哺乳动物表达15福明 亚型，每种亚型都具有独特的肌动蛋白组装特性，并在细胞中发挥特定作用。 尽管福尔明基因的突变与许多人类疾病有关，包括白血病前期 疾病和癌症，目前仍不清楚每种福尔马亚型的聚合活性是如何调节的 特定捆绑肌动蛋白结构的组装并参与特定的细胞过程。为了弥补这一点 由于理解上的差距，我们必须确定formins如何在捆绑的肌动蛋白结构中发挥作用 存在于细胞中。我们将通过描述福尔明介导的组装机制来解决这个问题 成束的肌动蛋白结构。我们的中心假设是，将福尔明结合的肌动蛋白丝掺入 成束结构通过将甲醛暴露于力、丝束和丝来调节聚合 切断。我们将结合使用生物物理学和细胞生物学方法来检验这一假设： 追求三个具体目标：（1）阐明力对福尔明介导机制的影响 细丝伸长率，（2）研究细丝成束与福尔明聚合之间的关系 活性，以及​​（3）评估丝周转对束状肌动蛋白结构组装的贡献。经过 建立福尔明引导的捆绑肌动蛋白组装机制，我们将获得以下基本见解： 福尔明调节的大量细胞过程。这项工作也将为 了解福明如何促进健康的细胞增殖和正常发育。