Mechanism of the Usher in Assembly and Secretion of Pili

霹雳虫的组装与分泌机制

• 批准号: 6636631
• 负责人: David G Thanassi
• 金额: $ 23.33万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6636631
• 关键词: Escherichia coli; bacteria infection mechanism; bacterial proteins; cell free system; epitope mapping; liposomes; membrane biogenesis; membrane model; membrane permeability; membrane proteins; molecular assembly /self assembly; molecular chaperones; pilus; urinary tract infection; virulence; Escherichia coli; bacteria infection mechanism; bacterial proteins; cell free system; epitope mapping; liposomes; membrane biogenesis; membrane model; membrane permeability; membrane proteins; molecular assembly /self assembly; molecular chaperones; pilus; urinary tract infection; virulence

DESCRIPTION (provided by the applicant): Pathogenic bacteria must assemble and secrete virulence factors in order to interact with their hosts and cause disease. Gram-negative bacteria have an outer membrane in addition to a cytoplasmic membrane and must secrete virulence factors across both these barriers. The mechanisms by which this occurs can be quite complex and are not well understood. The chaperone/usher pathway is a virulence protein secretion pathway that requires two components for secretion across the outer membrane: a periplasmic chaperone and an outer membrane protein termed an usher. The chaperone directs proper folding of the secreted proteins and prevents their engagement in non-productive interactions. The usher serves as an assembly platform at the outer membrane and provides a secretion channel to the cell surface. The chaperone/usher pathway is required for assembly and secretion of a superfamily of adhesive structures in a broad range of Gram-negative pathogens. The prototypical organelles assembled by this pathway are the P and type 1 pili expressed by uropathogenic Escherichia coli, the primary causative agent of urinary tract infections. P and type 1 pili are critical virulence factors, allowing binding and colonization of the kidney and bladder, respectively. The long-term goal of this proposal is to use pilus biogenesis by uropathogenic E. coli as a model system with which to understand virulence factor secretion in Gram-negative bacteria. More specifically, the structure and function of the usher will be investigated to elucidate the molecular mechanisms governing secretion across the outer membrane. The first specific aim is to create a detailed model of the structural arrangement of the usher in the outer membrane using computer analysis and epitope mapping techniques. The second specific aim is to probe function of the usher through generation and analysis of mutants. The third specific aim is to establish a cell-free system for pilus biogenesis based on reconstitution of the usher into liposomes. Such a system will provide an invaluable tool for studying the chaperone/usher pathway and analyzing mutants. The work described in this proposal will elucidate mechanisms of virulence factor secretion and create opportunities for the development of novel antimicrobial agents to treat not only urinary tract infections, but also a broad range of infectious diseases.

描述（由申请人提供）：病原细菌必须组装，并且 分泌毒力因素，以便与宿主互动并导致 疾病。革兰氏阴性细菌除了 细胞质膜，并且必须分泌这两种毒力因子 障碍。发生这种情况的机制可能很复杂，而不是 理解。伴侣/Usher途径是一种毒力蛋白分泌 途径需要两个分泌跨膜分泌的组成部分： 周质伴侣蛋白和外膜蛋白称为usher。这 伴侣指导分泌蛋白的适当折叠，并防止其 参与非生产互动。 Usher用作集会 外膜的平台，为电池提供了一个分泌通道 表面。组装和分泌需要伴侣/usher途径 粘合剂结构的超家族范围广泛的革兰氏阴性 病原体。该途径组装的原型细胞器是P和 尿道病大肠杆菌表达的1型pili，主要因果关系 尿路感染的药物。 P和1型Pili是关键的毒力 因素，允许肾脏和膀胱的结合和定植， 分别。该提议的长期目标是使用pilus生物发生 肝病大肠杆菌作为模型系统，以了解毒力 革兰氏阴性细菌的因子分泌。更具体地，结构 将研究迎接的功能，以阐明分子 控制整个外膜分泌的机制。第一个特定 目的是创建一个详细的模型 使用计算机分析和表位映射技术的外膜。这 第二个具体目的是通过一代和 突变体的分析。第三个具体目的是建立一个无单元的系统 用于基于usher重构为脂质体的生物发生。这样的 系统将为研究伴侣/usher提供宝贵的工具 途径和分析突变体。本提案中描述的工作将 阐明毒力因子分泌的机制，并为 新型抗菌剂的发展不仅治疗尿路 感染，但也有广泛的传染病。