How chlamydia generates cytoskeletal scaffolds and their role during infection

项目摘要 细胞内细菌沙眼衣原体是性传播疾病的主要原因， 全世界有超过1.5亿例感染性失明。一旦进入细胞，衣原体就以一种 寄生隔室称为内含物，其被包裹在肌动蛋白和微管支架中。肌动蛋白支架 提供内含物的完整性，而微管（MT）控制高尔基体在内含物周围的重新定位; 这些事件是衣原体生存所必需的。尽管细胞骨架重排对于 衣原体的生命周期，一个主要的差距存在的分子机制，用于控制这种细菌 细胞骨架此外，衣原体在感染期间将多个宿主细胞器重定向到其包含体。 值得注意的是，哪种细胞骨架支架控制这种重新定位仍有待确定。值得注意的是，这是一个 关键问题是细胞器的重新定位增强了脂质和营养物质转移到内含物中，然后 有助于包涵体膜的生长和细菌的复制。 使用最近建立的基因修饰衣原体菌株，我们建议研究新的衣原体的作用。 衣原体蛋白（也称为效应物）在细胞骨架支架的形成中起重要作用。这些效应器已经被 显示与转染细胞中的细胞骨架蛋白相互作用，因此是 在感染期间操纵细胞骨架。具体来说，我们将测试假设1）衣原体建立一个 由多种细菌和宿主蛋白组成的分子平台，以协调肌动蛋白和MT 感染期间的重排，和2）由于细胞骨架支架围绕内含物编织， 然后各种细胞器转向包涵体以促进衣原体的存活。 最终，这些信息将产生广泛的科学影响，因为（i）它将建立详细的机制， 衣原体利用它来重新利用两个主要的细胞骨架元素，使其自身受益，并将提供一个更好的 理解疾病进展;（ii）细胞骨架重排在癌症中起着关键作用 发展由于衣原体感染与癌症风险增加有关，了解 细胞骨架在感染过程中是如何重组的，这将有助于阐明这一现象;（iii）了解 控制细胞骨架动力学的机制将为基础生物学提供重要的见解 途径，和（iv）最后，一个详细的表征蛋白质控制细胞骨架动力学过程中， 衣原体感染将提供基本的工具，以筛选存在类似的效应，在其他主要 人类病原体也操纵宿主细胞骨架，特别是沙门氏菌，从而开辟了新的途径 分子发病机制的研究。

PROJECT SUMMARY The intracellular bacterium Chlamydia trachomatis is a major cause of sexually transmitted disease and infectious blindness with over 150 million cases worldwide. Once inside the cell, Chlamydia replicates in a parasitic compartment called an inclusion, which is encased in actin and microtubules scaffolds. Actin scaffolds provide inclusion integrity, while microtubules (MT) control Golgi repositioning around the inclusion; both of these events are necessary for Chlamydia survival. Despite the importance of cytoskeleton rearrangements for Chlamydia's life cycle, a major gap exists regarding the molecular mechanism used by this bacterium to control the cytoskeleton. Furthermore, Chlamydia redirects multiple host organelles to its inclusion during infection. Remarkably, which cytoskeleton scaffold controls this repositioning remains to be identified. Of note, this is a key question as organelle repositioning enhances lipid and nutrient transfer to the inclusion, which then contribute to the growth of the inclusion membrane and the replication of the bacteria. Using recently established genetically-modified Chlamydia strains, we propose to study the role of novel chlamydial proteins (also called effectors) in the formation of cytoskeleton scaffolds. These effectors have been shown to interact with cytoskeleton proteins in transfected cells and are, therefore, ideal candidates to manipulate cytoskeleton during infection. Specifically, we will test the hypotheses that 1) Chlamydia builds a molecular platform composed of multiple bacterial and host proteins to coordinate actin and MT rearrangements during infection, and 2) as cytoskeletal scaffolds are woven around the inclusion, various organelles are then diverted towards the inclusion to promote Chlamydia's survival. Ultimately, this information will have a broad scientific impact as (i) It will establish the detailed mechanism used by Chlamydia to repurpose two major cytoskeleton elements for its own benefit and will provide a better understanding of disease progression; (ii) Cytoskeleton rearrangement plays a critical role in cancer development. Since Chlamydia infection has been associated with an increased risk of cancer, understanding how the cytoskeleton is reorganized during infection will shed light on this phenomenon; (iii) Understanding the mechanism that controls cytoskeleton dynamics will provide critical insight into fundamental biological pathways, and (iv) Finally, a detailed characterization of the proteins that control cytoskeletal dynamics during Chlamydia infection will provide fundamental tools to screen for the presence of similar effectors in other major human pathogens that also manipulate host cytoskeleton, in particular Salmonella, thus opening new avenues of research in molecular pathogenesis.