The role of secreted effector proteins in Chlamydia trachomatis invasion

项目摘要 沙眼衣原体（C.t.）是导致非先天性失明的主要原因， 世界上最严重的传染性细菌感染，如果不及时治疗，可能会导致严重的后果。所有 衣原体是专性细胞内细菌，因此进入宿主细胞是病原体必需的 来完成它的复制周期并增殖。尽管入侵过程的关键性， 关于C.t.强行进入非吞噬细胞仍然是一个很大的知识 间隙当前模型的一个主要前提表明，预包装的交付有助于入侵 在病原体进入之前，常规III型分泌系统（cT 3SS）效应蛋白进入宿主细胞。我们 假设这些cT 3SS效应子的一个子集通过以下途径协调宿主细胞骨架的主动颠覆： 直接操纵肌动蛋白动力学的关键调节器。我们实验室的新数据表明，cT 3SS 效应蛋白TmeA与成核促进因子N-WASP结合，我们发现两者都是必需的 准备入侵在目标1中，我们将机械地确定TmeA如何调节N-WASP，并确定是否 这种相互作用促进了可能有助于细菌进入的关键膜特征如：膜皱褶， 基座形成和丝状伪足动态。鉴于入侵对细菌增殖的本质影响， 存活，C.t.很可能采用了多种入侵手段在目标2中，我们将评估复杂的相互作用 之间的TarP，TepP，和TmeA，并揭示其效应器功能的最终分子效应，并描述 这些效应物所针对的看似不同的途径如何汇聚在一起以确保衣原体入侵。 此外，我们将确定是否有其他cT 3SS效应物，仅表达于侵袭性EB形式， 衣原体是侵入非吞噬细胞所必需的。细菌和宿主的详细表征 在C.t.期间促进肌动蛋白细胞骨架重组所需的蛋白质。入侵将提供一个全面的 细胞内病原体，如C.t.，协同破坏细胞骨架调节因子入侵宿主 细胞

Project Summary Chlamydia trachomatis (C.t.) is the leading cause of non-congenital blindness and the most prevalent sexually transmitted bacterial infection in the world, which if left untreated can result in severe consequences. All chlamydiae are obligate intracellular bacteria and thus gaining entry into a host cell is essential for the pathogen to complete its replicative cycle and proliferate. Despite the critical nature of the invasion process, the molecular mechanisms and details regarding how C.t. forces its way into non-phagocytic cells remains a large knowledge gap. A major premise of the current model suggests that invasion is facilitated by delivery of prepackaged conventional type III secretion system (cT3SS) effector proteins into the host cell prior to pathogen entry. We hypothesize that a subset of these cT3SS effectors coordinate active subversion of the host cytoskeleton through direct manipulation of key regulators of actin dynamics. New data from our laboratory indicates that the cT3SS effector protein TmeA binds to the nucleation promoting factor N-WASP, both of which we show are essential for invasion. In Aim 1, we will mechanistically determine how TmeA regulates N-WASP and determine whether this interaction promotes key membrane features that likely aid in bacterial entry such as; membrane ruffling, pedestal formation, and filopodial dynamics. Given the essential nature of invasion to bacterial proliferation and survival, C.t. likely employs multiple measures for invasion. In Aim 2, we will evaluate the complex interplay between TarP, TepP, and TmeA and reveal the ultimate molecular effects of their effector function and describe how the seemingly disparate pathways targeted by these effectors converge to assure chlamydial invasion. Furthermore, we will determine whether other cT3SS effectors, only expressed in the invasive EB form of chlamydia, are necessary for invasion of non-phagocytic cells. Detailed characterization of the bacterial and host proteins required to promote reorganization of the actin cytoskeleton during C.t. invasion will provide a holistic view of how intracellular pathogens, such as C.t., coordinate subversion of cytoskeletal regulators to invade host cells.