Mechanism of the Usher in Assembly and Secretion of Pili

霹雳虫的组装与分泌机制

• 批准号: 6724911
• 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/6724911
• 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

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（由申请方提供）：病原菌必须组装并 分泌毒力因子，以便与宿主相互作用， 疾病革兰氏阴性菌除了具有外膜外，还具有外膜。 细胞质膜，并且必须分泌毒力因子穿过这两个 隔栏.发生这种情况的机制可能相当复杂， 很好理解。伴侣蛋白/引导蛋白途径是一种毒力蛋白分泌途径， 这一途径需要两种成分来分泌穿过外膜： 周质伴侣蛋白和称为引导者的外膜蛋白。的 伴侣蛋白指导分泌蛋白的正确折叠，并防止它们的 参与非生产性互动。引座员作为一个集会 在外膜的平台，并提供了一个分泌通道的细胞 面分子伴侣/引导剂途径是组装和分泌 在广泛的革兰氏阴性菌中的粘附结构超家族 病原体通过该途径组装的原型细胞器是P和 1型皮利，由尿路致病性大肠杆菌表达，主要致病 尿路感染的病原体。P和1型皮利是关键毒力 因子，允许肾脏和膀胱的结合和定殖， 分别这项建议的长期目标是利用菌毛生物发生， 肾盂肾炎大肠大肠杆菌作为了解毒力的模型系统 革兰氏阴性菌中的因子分泌。更具体地说， 和功能的引座员将进行调查，以阐明分子 控制外膜分泌的机制。第一特定 目的是建立一个详细的模型的结构安排的引座员 利用计算机分析和表位作图技术，的 第二个具体目的是通过生成来探索引导员的功能， 突变体分析第三个具体目标是建立一个无细胞系统 用于基于将引导剂重构为脂质体的菌毛生物发生。等 一个系统将提供一个宝贵的工具，研究伴侣/引座员 途径和分析突变体。本提案所述工作将 阐明毒力因子分泌的机制，并创造机会 新型抗菌药物的开发不仅可以治疗泌尿道， 感染，但也有广泛的传染病。