Regulation of Pore Formation by Type III Secretion System

III 型分泌系统对毛孔形成的调节

基本信息

批准号：
7924020
负责人：
Gloria I Viboud
金额：
$ 19.63万
依托单位：
STATE UNIVERSITY NEW YORK STONY BROOK
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-09-01 至 2012-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7924020
关键词：
Actins Adhesions Antigens Bacteria Binding Bioterrorism Cell membrane Cell physiology Cells Code Complex Confocal Microscopy Cytoplasm Cytoskeleton Dominant-Negative Mutation Epithelial Cells Event Family Genes Glycosphingolipids Hela Cells Homologous Protein Human Image Immune system Immunoprecipitation Infection Integrins Intestines Knock-out Life Light Lymphoid Tissue Mediating Membrane Membrane Proteins Modeling Modification Molecular Monoclonal Antibodies Nature Needles Organism Pasteurella pseudotuberculosis Pathogenesis Pathway interactions Plague Plasmids Play Pneumonia Pneumonic Plague Process Proteins Pseudomonas Pseudomonas aeruginosa Receptor Cell Regulation Research Research Project Grants Role Salmonella Shigella Signal Pathway Signal Transduction Signaling Molecule Site Structure Syringes Testing Toxin Travel Type III Secretion System Pathway Virulence Yersinia Yersinia enterocolitica Yersinia pestis antimicrobial appendage base clinically significant enteropathogenic Escherichia coli inhibitor/antagonist mutant novel pathogen polymerization rho rho GTP-Binding Proteins

项目摘要

DESCRIPTION (provided by applicant): The type III secretion system (TTSS) is essential for the pathogenesis of a number of gram-negative human pathogens, including three Yersinia species; Y. pseudotuberculosis and Y. enterocolitica, that cause infection of intestinal lymphoid tissues, and Y. pestis, the etiological agent of bubonic and pneumonic plague. In Yersinia, the TTSS is composed of a needle-like structure, three translocator proteins involved in the delivery of toxins into the host cell (YopB, YopD and LcrV), and six effector proteins (YopE, YopT, YopH, YopJ, YopO, YopM) that target different host cell signaling molecules to disarm the innate and adaptive host immune system. YopB and YopD are thought to insert in the plasma membrane forming a translocation channel. Wild type Yersinia does not disrupt the integrity of the host cell membrane during the translocation process. Bacteria deficient in YopE and YopT, or expressing a form of the two proteins unable to down-regulate Rho GTPases, have strong pore forming activity. We have found that pore formation results from a Yersinia-induced host cell signaling that requires YopB and YopD, and that is blocked by inactivation of Rho GTPases. Here, we postulate that activation of such signaling pathways might also be required for an efficient translocation process. We will aim to determine a) what signaling events are required for pore formation, and whether those signals play a role in translocation; b) whether activation of additional host cell signals, such as the 21 integrin pathway, may be involved in pore formation or translocation; c) whether YopD may stimulate host-signaling functions by interacting with host cell partners. The type III secretion system (TTSS) is essential for the virulence of a number of gram- negative human pathogens of enormous clinical significance. Some of these organisms include important entropathogens such as Salmonella spp., Shigella spp., Yersinia enterocolitica, Y. pseudotuberculosis and enteropathogenic Escherichia coli as well agents causing severe pneumonia, like the opportunistic bacteria Pseudomonas aeruginosa, or the deadly Yersinia pestis. Interestingly, Y. pestis, the etiological agent of plague, and a currently considered a class A bioterrorism agent, is closely related to Y. pseudotubeculosis, which causes an infection limited to intestinal lymphoid tissues. The studies proposed in this application constitute the frame of an exploratory research project aim at testing a new hypothesis: that the TTSS of Yersinia manipulates the host cell machinery to inject its own toxins. This type III-mediated signaling may not be restricted to Yersinia and might take place during infection of host cells with other pathogens that encode homologs of proteins, such as enteropathogenic E. coli, Shigella, and Salmonella. Studies that answer these questions might shed light on the molecular nature of the complex interaction between bacterial pathogens bearing TTSSs and the host cell. Importantly, components that act by modulating the TTSS are potential targets for novel antimicrobials.

描述（由申请人提供）：III 型分泌系统（TTSS）对于许多革兰氏阴性人类病原体（包括三种耶尔森氏菌）的发病机制至关重要；假结核耶尔森氏菌和小肠结肠炎耶尔森氏菌会引起肠道淋巴组织感染，鼠疫耶尔森氏菌是腺鼠疫和肺鼠疫的病原体。在耶尔森氏菌中，TTSS 由针状结构、参与将毒素递送到宿主细胞中的三种易位蛋白（YopB、YopD 和 LcrV）以及六种效应蛋白（YopE、YopT、YopH、YopJ、YopO、 YopM）针对不同的宿主细胞信号分子来解除先天性和适应性宿主免疫系统的武装。 YopB 和 YopD 被认为插入质膜中形成易位通道。野生型耶尔森氏菌在易位过程中不会破坏宿主细胞膜的完整性。缺乏 YopE 和 YopT 或表达无法下调 Rho GTPases 的两种蛋白质的细菌具有很强的孔形成活性。我们发现孔的形成是耶尔森菌诱导的宿主细胞信号传导的结果，该信号传导需要 YopB 和 YopD，并且可通过 Rho GTPases 的失活来阻断。在这里，我们假设有效的易位过程也可能需要激活此类信号通路。我们的目标是确定 a) 孔形成需要哪些信号事件，以及这些信号是否在易位中发挥作用； b) 其他宿主细胞信号（例如21整合素途径）的激活是否可能参与孔形成或易位； c) YopD是否可以通过与宿主细胞伙伴相互作用来刺激宿主信号传导功能。 III 型分泌系统 (TTSS) 对于许多具有巨大临床意义的革兰氏阴性人类病原体的毒力至关重要。其中一些生物体包括重要的内病原体，例如沙门氏菌属、志贺氏菌属、小肠结肠炎耶尔森氏菌、假结核耶尔森氏菌和肠病性大肠杆菌，以及引起严重肺炎的病原体，例如机会性细菌铜绿假单胞菌或致命的鼠疫耶尔森氏菌。有趣的是，鼠疫的病原体、目前被认为是 A 类生物恐怖制剂的鼠疫耶尔森氏菌与假结核耶尔森氏菌密切相关，后者引起仅限于肠道淋巴组织的感染。本申请中提出的研究构成了一个探索性研究项目的框架，旨在测试一个新的假设：耶尔森氏菌的 TTSS 操纵宿主细胞机器注入自己的毒素。这种 III 型介导的信号传导可能不仅限于耶尔森氏菌，也可能发生在宿主细胞被编码蛋白质同源物的其他病原体（例如致病性大肠杆菌、志贺氏菌和沙门氏菌）感染期间。回答这些问题的研究可能会揭示携带 TTSS 的细菌病原体与宿主细胞之间复杂相互作用的分子性质。重要的是，通过调节 TTSS 发挥作用的成分是新型抗菌药物的潜在目标。