Microbial mobilization of the actin cytoskeleton

项目摘要/摘要 肌动蛋白细胞骨架对细胞的性质和行为至关重要，包括形状、迁移和分裂， 以及动物发育过程中的细胞间连接和融合。因为这些众多的 细胞生理学中的基本功能，肌动蛋白功能障碍也是导致发病的常见因素， 例如炎症、心血管疾病、癌症转移和微生物感染。尽管有很多人 然而，多年的研究了解肌动蛋白组装是如何在细胞质中调节和利用的，以及 细胞内事件、细胞行为和细胞间相互作用的核仍然是一个关键的悬而未决的问题 在细胞生物学中。我的实验室采取了一种独特的方法来解决这一重要的知识差距，即 作为了解肌动蛋白的窗口，检查感染微生物与肌动蛋白细胞骨架之间的相互作用 规范和功能。我们的方法利用了这样一个事实，即许多感染微生物在宿主细胞上定居 通过它们靶向肌动蛋白的能力，并建立在大量研究相互作用的例子上 微生物和宿主细胞加深了我们对细胞骨架动力学以及膜的了解 贩运、细胞周期调节、蛋白质循环和细胞死亡。 这项Mira申请中描述的研究利用微生物作为工具来解决三个基本问题 细胞生物学问题：(1)肌动蛋白在膜上的聚合如何被调节和动员以驱动 运动？(2)肌动蛋白如何以及为什么运输到细胞核内并在细胞核内聚合以进行基因表达， 核组织、核内运动和核膜动力学？(3)肌动蛋白聚合是如何进行的 质膜突起被用来诱导细胞-细胞融合？我们将调查这些问题 使用三种模型微生物，每一种都以一种独特而强大的方式动员肌动蛋白 仪器：海洋分枝杆菌作为一种工具来了解肌动蛋白在膜上组装的调节 推动细胞内运动；加州链球杆状病毒多核型多角体病毒作为工具 了解肌动蛋白在细胞核中的调节和功能；以及泰兰伯克霍尔德氏菌作为工具 了解肌动蛋白在细胞-细胞融合中的作用。通过利用我们在微生物学和细胞生物学方面的专业知识， 采用微生物和哺乳动物遗传方法的协同组合，并使用生化， 通过生物物理和成像方法，我们在推动该领域向前发展方面具有得天独厚的优势。我们的结果将 加深我们对肌动蛋白调控机制的理解，并可能为 诊断、治疗和预防与肌动蛋白功能障碍相关的疾病，包括炎症性和 心血管疾病、癌症和微生物感染。

PROJECT SUMMARY/ABSTRACT The actin cytoskeleton is crucial for cellular properties and behaviors including shape, migration, and division, as well as for cell-cell connections and fusion during animal development. Because of these numerous essential functions in cell physiology, actin dysfunction is also a common contributor to pathogenesis, for example in inflammation, cardiovascular disease, cancer metastasis, and microbial infection. Despite many years of study, however, understanding how actin assembly is regulated and harnessed in the cytoplasm and nucleus for intracellular events, cellular behaviors, and cell-cell interactions remains a key outstanding problem in cell biology. My lab has taken a distinctive approach to address this important gap in knowledge, which is to examine the interactions between infectious microbes and the actin cytoskeleton as a window into actin regulation and function. Our approach leverages the fact that many infectious microbes colonize host cells through their ability to target actin, and builds on numerous examples of how studying the interactions between microbes and host cells has enhanced our understanding of cytoskeleton dynamics, as well as membrane trafficking, cell cycle regulation, protein recycling, and cell death. The research described in this MIRA application makes use of microbes as tools to address three fundamental cell biological questions: (1) How is actin polymerization at membranes regulated and mobilized to drive movement? (2) How and why is actin transported into and polymerized within the nucleus for gene expression, nuclear organization, intranuclear movement, and nuclear envelope dynamics? (3) How is actin polymerization in plasma membrane protrusions harnessed to induce cell-cell fusion? We will investigate these questions using three model microbes, each of which mobilizes actin in a manner that makes it a unique and powerful instrument: Mycobacterium marinum as a tool to understand the regulation of actin assembly at membranes to drive intracellular movement; the baculovirus Autographa californica multiple nucleopolyhedrovirus as a tool to understand the regulation and function of actin in the nucleus; and Burkholderia thailandensis as a tool to understand the role of actin in cell-cell fusion. By leveraging our expertise in both microbiology and cell biology, deploying a synergistic combination of microbial and mammalian genetic methods, and employing biochemical, biophysical and imaging approaches, we are uniquely positioned to advance the field forward. Our results will enhance our understanding of the mechanisms of actin regulation and may provide new insights into diagnosing, treating, and preventing diseases associated with actin dysfunction including inflammatory and cardiovascular diseases, cancer, and microbial infection.