CopN mechanism as a key to understanding Type Three Secretion in bacteria

CopN 机制是理解细菌三型分泌的关键

• 批准号: 9305827
• 负责人: BENJAMIN W SPILLER
• 金额: $ 39.21万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9305827
• 关键词: Antibiotic Resistance; Antibiotics; Bacteria; Bacterial Infections; Binding; Binding Proteins; Binding Sites; Biochemistry; Categories; Cell membrane; Cell physiology; Cells; Centers for Disease Control and Prevention (U.S.); Chlamydia; Chlamydophila psittaci; Complex; Crystallization; Cytoplasm; Cytoskeleton; Cytosol; Data; Development; Drug Targeting; Drug resistance; Escherichia coli; Eukaryotic Cell; Gram-Negative Bacteria; Host Defense; Lead; Link; Mediating; Membrane; Methicillin Resistance; Microtubules; Modification; Molecular; Molecular Chaperones; Mutagenesis; Mutation; Needles; Pathogenicity; Peptides; Pharmaceutical Preparations; Process; Protein Secretion; Proteins; Pseudomonas; Public Health; Publishing; Regulation; Role; Salmonella; Shigella; Staphylococcus aureus; Stimulus; Structure; System; Testing; Therapeutic; Tubulin; Variant; Virulence; Virulence Factors; X-Ray Crystallography; Yersinia enterocolitica; Yersinia pestis; design; experimental study; genetic regulatory protein; inhibitor/antagonist; kinetosome; mortality; new therapeutic target; novel; pathogen; periplasm; polymerization; prevent; public health relevance; response; scaffold

DESCRIPTION (provided by applicant): Antibiotic resistant and pathogenic Gram-negative bacteria are an increasingly important public health concern and are expected to soon surpass methicillin-resistant S. aureus as the principal cause of mortality due to bacterial infection. Despite evident need, new antibiotics are not being developed at an adequate rate and most effort involves modifications of existing drugs, rather than identification and development of novel drug targets. An attractive target for the much-needed development of new antibiotic therapeutics is the Type Three Secretion System (T3SS), a virulence factor delivery machine that is conserved among over 25 species of Gram-negative bacteria (including category A, B, and C pathogens). The T3SS is a multi-protein needle-like machine that spans the bacterial and host membranes and delivers protein translocator molecules into the membrane of the target cell and effector molecules into the cytosol of the target cell. The effectors promote virulence by co-opting cellular processes and subverting host defenses. While the molecular mechanisms of TTSS regulation are largely unknown, key requirements are that the pore is constitutively closed, that it opens in response to a stimulus, and secretion is an orderly, hierarchical process. Effectors are secreted directly into the host cell, through a preformed translocon pore. This pore is composed of secreted translocator proteins that must be secreted prior to effectors. A key regulatory protein is the "plug" which blocks the pore. Following plug protein secretion translocators are secreted, followed by effectors. In strains where plug proteins have been deleted, effectors are secreted constitutively, translocator secretion is severely defective, and the strains are non-virulent. The origin of the essential translocator-effector hierarchy is unknown. We have recently determined the first structure of a plug protein bound to a chaperone for a translocator. This structure reveals that plugs are molecular scaffolds that are tethered to translocators. We intend to further elucidate the role of plug-translocator scaffolding in multiple gram-negative species, and to understand the novel effector function of the Chlamydial plug protein. We have shown these proteins to possess novel tubulin binding function are poised, with our recent structure, to determine the molecular strategies that Chlamydia use to regulate the host's microtubule cytoskeleton. Finally, we will evaluate the chaperone-translocator interaction as a novel therapeutic target for the development of broad-spectrum antibiotics.

描述（由申请人提供）：抗生素耐药性致病性革兰氏阴性菌是一个日益重要的公共卫生问题，预计很快将超过耐甲氧西林金黄色葡萄球菌，成为细菌感染导致死亡的主要原因。尽管存在明显的需求，但新抗生素的开发速度还不够，而且大多数努力涉及对现有药物的修改，而不是识别和开发新的药物靶点。对于急需开发的新抗生素疗法来说，一个有吸引力的目标是三型分泌系统（T3SS），这是一种毒力因子传递机器，在超过 25 种革兰氏阴性细菌（包括 A、B 和 C 类病原体）中保守。 T3SS 是一种多蛋白针状机器，可跨越细菌和宿主细胞膜，将蛋白质易位分子递送到靶细胞膜中，将效应分子递送到靶细胞胞质溶胶中。 The effectors promote virulence by 选择细胞过程并颠覆宿主防御。 虽然 TTSS 调节的分子机制在很大程度上尚不清楚，但关键要求是孔本质上是封闭的，它响应刺激而打开，并且分泌是一个有序的、分层的过程。 效应子通过预先形成的易位子孔直接分泌到宿主细胞中。该孔由分泌的易位蛋白组成，必须在效应器之前分泌。一个关键的调节蛋白是堵塞毛孔的“塞子”。插头蛋白分泌后，易位蛋白被分泌，随后是效应蛋白。在插头蛋白被删除的菌株中，效应子是组成型分泌的，易位子分泌有严重缺陷，并且菌株是无毒力的。基本易位器-效应器层次结构的起源尚不清楚。我们最近确定了与易位子伴侣结合的插头蛋白的第一个结构。这种结构揭示了插头是与易位子相连的分子支架。我们打算进一步阐明插头转运支架的作用 在多种革兰氏阴性物种中，并了解衣原体插头蛋白的新效应子功能。我们已经证明，这些蛋白质具有新颖的微管蛋白结合功能，并且根据我们最新的结构，可以确定衣原体用于调节宿主微管细胞骨架的分子策略。最后，我们将评估分子伴侣-易位子相互作用作为广谱抗生素开发的新治疗靶点。