Dissecting the means by which type 3 substrates are defined & secreted

剖析 3 类底物的定义方式

• 批准号: 10589974
• 负责人: CAMMIE LESSER
• 金额: $ 3.13万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10589974
• 关键词: ATP phosphohydrolase; Address; Binding; Biochemical; Biological Assay; Biological Models; Cells; Complex; Cytosol; Data; Development; Disease; Dissociation; Engineering; Escherichia; Escherichia coli; Family; Genetic; Goals; Human; Infection; Lead; Mammalian Cell; Mediating; Membrane; Modeling; Molecular; Molecular Chaperones; Multi-Drug Resistance; Mutagenesis; N-terminal; Nature; Pathogenicity; Pathway interactions; Pharmaceutical Preparations; Phylogenetic Analysis; Physiological; Play; Process; Protein Secretion; Proteins; Proton-Motive Force; Pseudomonas aeruginosa; Publishing; RNA; Ribosomes; Role; Salmonella; Salmonella enterica; Shigella; Shigella flexneri; Solid; Sorting; Technology; Translations; Type III Secretion System Pathway; Variant; Virulence; Yersinia; antimicrobial; antimicrobial drug; experimental study; follow-up; genetic approach; high throughput screening; in vivo; insight; nanomachine; novel; pathogen; pathogenic bacteria; recruit; resistant strain; ribosome profiling; targeted agent

The virulence of many human bacterial pathogens is dependent on transkingdom nanomachines, including type III secretion systems (T3SSs), which act to directly deliver tens of virulence proteins, often referred to as effectors, into the cytosol of mammalian cells. Many critical gaps exist in our understanding of how type III secreted (T3S) proteins, referred to as effectors, are defined and delivered to the T3S apparatus (T3SA). While each pathogen injects its own unique set of effectors into hosts, components of their machines share a high degree of similarity. For several decades, the dogma has been that the effector secretion is dependent on small acidic T3S chaperones that bind to their N-terminal regions. These chaperones control the hierarchy of secretion of proteins by mediating their recruitment to the sorting platform, a complex that cycles between the cytosol and membrane-embedded T3SA. Interestingly, cognate chaperones have not yet been identified for the majority of T3S effectors, including those from intensively studied Salmonella, Yersinia, Shigella and pathogenic Escherichia T3SSs. Here, we present data that support the existence of a noncanonical T3SS chaperone-independent (CI) pathway likely conserved across numerous phylogenetically distinct T3SS families. Here, using the Shigella flexneri T3SS as a model system, we propose to: 1. Determine how T3S chaperones are recruited to the sorting platform. Using the Protein Interaction 2. Dissect the molecular mechanisms by which CI effectors are recognized and delivered to the T3SA. 3. Investigate the existence of a co-translational ATPase-independent type III secretion pathway. Together the proposed studies shown not only advance our understanding regarding how T3S effectors are defined and delivered to the T3SA, but also result in the identification of targets for the development of novel antimicrobial agents that target the virulence of the large family of Gram-negative bacterial pathogens whose virulence is dependent on a functional T3SS.

许多人类细菌病原体的毒力依赖于跨界纳米机器，包括 III 型分泌系统 (T3SS)，可直接传递数十种毒力蛋白，通常称为 效应器进入哺乳动物细胞的细胞质。我们对 III 型如何理解存在许多关键差距 分泌型 (T3S) 蛋白（称为效应器）被定义并递送至 T3S 装置 (T3SA)。尽管 每种病原体将其独特的一组效应器注入宿主，其机器的组件共享高 相似程度。几十年来，人们一直认为效应器的分泌取决于 与其 N 末端区域结合的小型酸性 T3S 伴侣。这些伴侣控制着等级制度 通过介导蛋白质被招募到分选平台来分泌蛋白质，分选平台是一个在蛋白质之间循环的复合体 胞浆和膜嵌入的 T3SA。有趣的是，尚未确定同源伴侣 大多数 T3S 效应子，包括来自深入研究的沙门氏菌、耶尔森氏菌、志贺氏菌和 致病性大肠杆菌 T3SS。在这里，我们提供支持非规范 T3SS 存在的数据 分子伴侣独立（CI）途径可能在许多系统发育上不同的 T3SS 中保守 家庭。在这里，使用福氏志贺菌 T3SS 作为模型系统，我们建议： 1. 确定如何将 T3S 伴侣招募到分拣平台。利用蛋白质相互作用 2. 剖析 CI 效应子被识别并传递至 T3SA 的分子机制。 3. 研究共翻译 ATP 酶独立的 III 型分泌途径的存在。 总之，拟议的研究不仅增进了我们对 T3S 效应器如何发挥作用的理解 定义并交付给 T3SA，还确定了开发新型药物的目标 针对革兰氏阴性细菌病原体大家族的毒力的抗菌剂 毒力取决于功能性 T3SS。