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）：抗生素耐药性和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的S。金黄色葡萄球菌是由于细菌感染导致死亡的主要原因。尽管有明显的需求，但新抗生素的开发速度并不足够，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。急需开发的新抗生素治疗剂的一个有吸引力的靶标是三型分泌系统（T3 SS），其是在超过25种革兰氏阴性细菌（包括A类、B类和C类病原体）中保守的毒力因子递送机器。T3 SS是一种多蛋白针状机器，其跨越细菌和宿主膜，并将蛋白质转运分子递送到靶细胞的膜中，并将效应分子递送到靶细胞的胞质溶胶中。效应子通过以下方式促进毒力： 利用细胞过程破坏宿主防御 虽然TTSS调节的分子机制在很大程度上是未知的，但关键的要求是孔是组成性关闭的，它响应于刺激而打开，并且分泌是一个有序的、分级的过程。 效应子通过预先形成的易位子孔直接分泌到宿主细胞中。该孔由必须在效应物之前分泌的分泌的转运蛋白组成。一个关键的调节蛋白质是堵塞孔的“塞子”。在栓蛋白分泌之后，分泌易位子，随后是效应子。在塞蛋白已被删除的菌株中，效应子组成型分泌，转运子分泌严重缺陷，并且菌株是无毒的。重要的移位器-效应器层级的起源是未知的。我们最近已经确定了第一个结构的插头蛋白绑定到伴侣转运。这种结构揭示了塞子是拴在转位器上的分子支架。我们打算进一步阐明插件转运支架的作用 在多种革兰氏阴性菌中，并了解衣原体栓蛋白的新效应子功能。我们已经表明，这些蛋白质具有新的微管蛋白结合功能的准备，与我们最近的结构，以确定衣原体用来调节宿主的微管细胞骨架的分子策略。最后，我们将评估伴侣转运蛋白相互作用作为一种新的治疗目标的发展广谱抗生素。