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细菌是越来越重要的公共卫生问题，预计将很快超过耐甲氧西林的金黄色葡萄球菌作为细菌感染引起的死亡的主要原因。尽管需要明显，但新的抗生素并未以足够的速度开发，大多数努力涉及现有药物的修改，而不是鉴定和开发新型药物靶标。新型抗生素治疗剂急需开发的一个有吸引力的目标是三型分泌系统（T3SS），这是一种毒力因子输送机，在25种革兰氏阴性细菌（包括A类，B类和C病原体）中保守。 T3SS是一种多蛋白针状的机器，它跨细菌和宿主膜，并将蛋白质转运剂分子传递到靶细胞和效应分子的膜中，进入靶细胞的细胞质。效应子通过 选择细胞过程和颠覆宿主防御。 尽管TTSS调控的分子机制在很大程度上未知，但关键要求是孔是组成型封闭的，它是响应刺激而打开的，而分泌是一个有序的，分层的过程。 效应子通过预先形成的转运孔直接分泌到宿主细胞中。该孔由必须在效应子之前分泌的分泌转运蛋白组成。一个关键的调节蛋白是阻塞孔的“插头”。插头蛋白质分泌的转运剂被分泌，其次是效应子。在已删除插头蛋白的菌株中，效应子是组成型分泌的，转运剂的分泌严重缺陷，菌株是非毒气的。必需转运器效应层次结构的起源尚不清楚。我们最近确定了插头蛋白与伴侣蛋白结合的第一个结构，用于转运剂。该结构表明插头是分子支架，它们束缚在转运器上。我们打算进一步阐明插件转换器脚手架的作用 在多个革兰氏阴性物种中，并了解衣原体塞蛋白的新型效应子功能。我们已经证明，这些蛋白质具有新型的微管蛋白结合功能，并通过我们最近的结构来确定衣原体用于调节宿主微管细胞骨架的分子策略。最后，我们将评估伴侣蛋白转换剂的相互作用，作为开发广谱抗生素的新型治疗靶标。