Effectors of Brucella intracellular replication

布鲁氏菌细胞内复制的效应子

• 批准号: 9283905
• 负责人: JEAN A CELLI
• 金额: $ 45.68万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-05 至 2021-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9283905
• 关键词: Address; Affect; Animal Diseases; Area; Bacteria; Biochemistry; Biogenesis; Brucella; Brucellosis; Cell membrane; Cell physiology; Cells; Cellular biology; Data; Disease; Endoplasmic Reticulum; Event; Generations; Goals; Golgi Apparatus; Growth; Infection; Injectable; Integration Host Factors; Knowledge; Mammalian Cell; Mediating; Microbe; Molecular; Natural Immunity; Organelles; Pathogenesis; Pathogenicity; Pathway interactions; Play; Process; Proliferating; Proteins; Public Health; Research; Role; Testing; Time; Type IV Secretion System Pathway; Vacuole; Virulence; Widespread Disease; Work; Zoonoses; base; cellular targeting; disorder control; experimental study; human disease; insight; microbial; novel; pathogen; permissiveness; protein degradation; trafficking; trans-Golgi Network; ubiquitin-protein ligase

Project Summary Intracellular bacterial pathogens cause a large number of diseases of public health importance. Their intracellular cycle is key to virulence and culminates in the biogenesis of a niche dedicated to their survival, proliferation or persistence, a feat achieved via their subversion of host cell functions. Determining the mechanisms used to create these niches is critical to understanding their pathogenesis, providing broad insights into pathogenic themes shared by microbes. Bacterial subversion of host cell functions invokes delivery of effector proteins, whose modes of action hold keys to their pathogenic mechanisms. Bacteria of the genus Brucella, the causative agents of the world-widespread zoonosis brucellosis, generate a replication-permissive organelle, the Brucella-containing vacuole (rBCV), which is essential to their pathogenesis and derived from the host endoplasmic reticulum (ER). rBCV biogenesis requires the Brucella VirB Type IV secretion system (T4SS) and host secretory trafficking, suggesting it is controlled by T4SS-delivered effector proteins that modulate specific secretory functions. Yet, the bacterial effectors and host factors of rBCV biogenesis are mostly unknown. We recently discovered Brucella VirB T4SS effectors (BspA, BspB and BspF) that target the host secretory pathway, contribute to either rBCV biogenesis or bacterial growth within rBCVs, and interact with various host proteins functionally associated with either ER-associated degradation (ERAD) or secretory trafficking at the Golgi apparatus. These findings provide timely opportunities to address outstanding questions about the molecular mechanisms of rBCV biogenesis. Here we propose to elucidate the mechanisms by which the newly identified T4SS effector proteins BspA, BspB and BspF modulate distinct host secretory functions to promote rBCV biogenesis and bacterial proliferation. We will use molecular and cellular approaches to first dissect the mode of action of BspB in modulating Golgi-associated secretory trafficking via its interaction with the COG complex, and define how it contributes to rBCV biogenesis. Second, we will determine whether BspF targeting of optineurin (OPTN)-mediated functions in post-Golgi vesicular trafficking mediates its role in Brucella intracellular replication. Last, we will examine whether BspA modulates ER-associated degradation (ERAD) via its targeting of the ERAD E3 ubiquitin ligase MARCH6 to facilitate rBCV biogenesis and Brucella proliferation. The successful completion of this project will provide the first characterizations of Brucella effectors involved in rBCV biogenesis via targeting of host secretory functions. By identifying novel host functions involved in the Brucella intracellular cycle, the proposed research will define new paradigms of pathogenic exploitation of the host secretory pathway applicable to the many intracellular microbes that target this cellular compartment, therefore having a broad impact on the research areas of microbial pathogenesis, cell biology and innate immunity.

项目概要 细胞内细菌病原体引起大量具有公共卫生重要性的疾病。他们的 细胞内循环是毒力的关键，并最终导致专门针对其细胞的生态位的生物发生。 生存、增殖或持久性，这是通过破坏宿主细胞功能而实现的壮举。 确定用于创建这些生态位的机制对于了解其发病机制至关重要， 提供对微生物共有的致病主题的广泛见解。细菌颠覆宿主细胞 功能调用效应蛋白的传递，其作用模式掌握其致病性的关键 机制。布鲁氏菌属细菌，世界范围内人畜共患病的病原体 布鲁氏菌病，产生一种允许复制的细胞器，即含有布鲁氏菌的液泡（rBCV），它是 其发病机制至关重要，源自宿主内质网 (ER)。 rBCV生物合成 需要布鲁氏菌 VirB IV 型分泌系统 (T4SS) 和宿主分泌运输，表明它 由 T4SS 传递的效应蛋白控制，调节特定的分泌功能。然而， rBCV 生物发生的细菌效应因子和宿主因素大多未知。我们最近发现 布鲁氏菌 VirB T4SS 效应子（BspA、BspB 和 BspF）以宿主分泌途径为目标，有助于 rBCV 生物发生或 rBCV 内细菌生长，并与各种宿主蛋白​​相互作用 与 ER 相关降解 (ERAD) 或高尔基体分泌性运输功能相关 设备。这些发现为解决有关的突出问题提供了及时的机会 rBCV 生物发生的分子机制。在此，我们建议阐明其机制 新鉴定的 T4SS 效应蛋白 BspA、BspB 和 BspF 调节不同的宿主分泌功能 促进 rBCV 生物合成和细菌增殖。我们将使用分子和细胞方法 首先剖析 BspB 通过其调节高尔基体相关分泌物运输的作用模式 与 COG 复合物的相互作用，并定义它如何促进 rBCV 生物发生。其次，我们将 确定 BspF 是否靶向高尔基体后囊泡中的 optineurin (OPTN) 介导的功能 运输介导其在布鲁氏菌细胞内复制中的作用。最后，我们将检查 BspA 是否 通过靶向 ERAD E3 泛素连接酶 MARCH6 调节 ER 相关降解 (ERAD) 促进 rBCV 生物发生和布鲁氏菌增殖。该项目的顺利完成将 通过靶向宿主提供参与 rBCV 生物发生的布鲁氏菌效应子的第一个特征 分泌功能。通过识别布鲁氏菌细胞内循环中涉及的新宿主功能， 拟议的研究将定义宿主分泌途径致病性利用的新范式 适用于许多针对该细胞区室的细胞内微生物，因此具有 对微生物发病机制、细胞生物学和先天免疫的研究领域产生了广泛影响。