A molecular switch of the type III secretion system in Chlamydia trachomatis

描述（由申请人提供）：沙眼衣原体III型分泌系统的分子开关。沙眼是全世界最常见的性传播疾病的病原体，是一个重大的公共卫生负担。女性生殖器衣原体感染的严重后遗症包括盆腔炎、宫外孕和输卵管不孕。C.沙眼衣原体是III型分泌系统（T3 SS），其直接将蛋白质效应物递送到宿主细胞胞质溶胶中以破坏宿主免疫并使细菌能够在宿主中存活。本课题的目的是研究C.沙眼衣原体控制III型分泌和基因表达，有助于疾病的发病机制。我们假设T3 SS活性在C.沙眼衣原体感染的分子开关，由CT663和它的蛋白伴侣。这一假设得到了我们的新发现的有力支持，衣原体CT663是一种双功能蛋白质，既作为一个转录调节因子，与RNA聚合酶的相互作用？66和CopN的T3 SS分子伴侣，其是T3 SS的调节剂以及效应物。我们的具体目标是：目标1。为了检验CT663形成III型分泌活性所必需的蛋白复合物的假设。我们将描述CT663及其合作伙伴的动态相互作用，以及这些相互作用如何影响分泌活性，使用定量分析蛋白质-蛋白质相互作用，免疫检测和肠致病性大肠杆菌（EPEC）系统。目标2.为了验证CT663差异调节基因转录的假设。这一目标将 使用我们建立的重组转录测定法来实现？66 RNA聚合酶的体外和E.杆菌这些研究将揭示T3 SS活性如何影响C.沙眼感染，反之亦然。这个项目将提供重要的见解，如何C。沙眼衣原体利用T3 SS通过在感染期间协调T3 SS的调节事件和基因表达而在细胞内小生境中存活。我们的研究将大大扩展目前的知识的C。沙眼衣原体感染过程中，并有助于确定潜在的药物靶点的新疗法，可以显着减少由C.沙眼感染

DESCRIPTION (provided by applicant): A molecular switch of the type III secretion system in Chlamydia trachomatis The obligate intracellular bacterium C. trachomatis is the causative agent of the most common sexually transmitted disease worldwide and represents a significant public health burden. The severe sequelae of genital chlamydial infections in women include pelvic inflammatory disease, ectopic pregnancy and tubal infertility. A key virulence mechanism of C. trachomatis is the type III secretion system (T3SS) that directly delivers protein effectors into the host cell cytosol to subvert host immunity and enables bacterial survival in hosts. The objective of this project is to study the mechanism by which C. trachomatis controls type III secretion and gene expression, contributing to disease pathogenesis. We hypothesize that T3SS activity is regulated and coupled to gene transcription during C. trachomatis infection by a molecular switch, consisting of CT663 and its protein partners. This hypothesis is strongly supported by our novel finding that chlamydial CT663 is a bi-functional protein acting as both a transcription regulator that interacts with RNA polymerase containing ? 66 and a T3SS chaperone for CopN, which is a regulator as well as an effector of the T3SS. Our specific aims are: Aim 1. To test the hypothesis that CT663 forms a protein complex necessary for type III secretion activity. We will characterize the dynamic interactions of CT663 and its partners, and how these interactions impact the secretion activity using quantitative assays for protein-protein interactions, immunodetection, and an enteropathogenic Escherichia coli (EPEC) system. Aim 2. To test the hypothesis that CT663 differentially regulates the gene transcription. This aim will be achieved using our established transcription assays with reconstituted ?66RNA polymerase in vitro and in E. coli. These studies will uncover how T3SS activity affects gene expression during C. trachomatis infection and vice versa. This project will provide important insights into how C. trachomatis utilizes T3SS to survive in an intracellular niche by coordinating the regulatory events of the T3SS and gene expression during infection. Our research will significantly expand current knowledge of the C. trachomatis infection process and contribute to the identification of potential drug targets for new therapies that could significantly reduce the public health burden caused by C. trachomatis infection.