Structure-function analysis of type IVB secretion systems

IVB型分泌系统的结构-功能分析

基本信息

批准号：
10160783
负责人：
Joseph P Vogel
金额：
$ 51.18万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-06-10 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10160783
关键词：
Address Alveolar Macrophages Bacteria Bacterial Infections Cell Nucleus Cell physiology Cells Complex Coupling Coxiella Cryoelectron Microscopy Cytoplasm DNA Development Disease Drug Targeting Drug usage Environment Eukaryota Family Future Genes Goals Gram-Negative Bacteria Growth Health Human Image Individual Knowledge Legionella Legionella pneumophila Legionnaires&apos Disease Light Lung Lysosomes Macromolecular Complexes Mediating Molecular Molecular Chaperones Organism Pathway interactions Phagocytes Phagosomes Pharmacotherapy Phase Plasmids Pneumonia Proteins Protozoa Research Rhizobium radiobacter Role Structure System Therapeutic Therapeutic Intervention Type IV Secretion System Pathway Vacuole Virulence Virulence Factors bactericide base cell envelope drug development follow-up insight macrophage molecular targeted therapies multidisciplinary mutant novel pathogen pathogenic bacteria prevent receptor secretion process targeted treatment trait

项目摘要

Abstract Legionella pneumophila is a Gram-negative bacteria that replicates inside protozoa in the environment but can also replicate within alveoloar macrophages, thereby causing a pneumonia-like disease called Legionnaires’ disease. L. pneumophila is able to survive and replicate within normally bactericidal phagocytic cells by altering their endocytic pathway and preventing rapid phagosome-lysosome fusion. L. pneumophila perturbs normal host cell function by injecting a large number of virulence factors into the host cell cytoplasm via a type IVB secretion system (T4BSS). The L. pneumophila T4BSS is encoded by twenty- seven dot/icm genes, which encode a large macromolecular complex in the bacterial cell envelope. The Dot/Icm system is absolutely required for intracellular growth and virulence. In contrast, the majority of the ~300 Dot/Icm substrates appear to be dispensable for both traits due to multiple levels of redundancy. Therefore, the L. pneumophila Dot/Icm represents the most viable target for therapeutic intervention. Although a significant amount of information has been acquired about the assembly and function of the Dot/Icm system, many questions remain. This proposal will follow-up on a number of recent advances on the Dot/Icm T4BSS. These include the discovery that the Dot/Icm system is located at the poles of the bacterium and polar export of substrates by this specialized secretion system is required for proper intracellular targeting of the LCV (Legionella containing vacuole). The second major advance was the determination of the structure of the c-terminus of DotL bound to the secretion chaperones. The final advance was the acquisition of the first image of this secretion apparatus by cryoEM. Overall this research relates to human health in several ways. First, establishing the mechanism used by L. pneumophila to survive and replicate inside macrophages will provide additional insight into how it causes disease and may reveal novel targets to be used for drug therapy. Second, since specialized secretion systems are commonly used by a variety of bacterial pathogens, knowledge gained about the L. pneumophila secretion apparatus is likely to be applicable to understanding the molecular mechanisms of virulence used by other pathogens, and could serve as the basis to prevent or treat a number of different diseases.

抽象的嗜肺军团菌是一种革兰氏阴性细菌，可在环境中的原生动物内复制，但也可以在肺泡巨噬细胞内复制，从而引起一种类似肺炎的疾病，称为军团菌病能够在正常杀菌条件下存活和复制。通过改变吞噬细胞的内吞途径并阻止快速吞噬体-溶酶体融合 L. 嗜肺军团菌通过向宿主注入大量毒力因子来扰乱宿主细胞的正常功能嗜肺军团菌T4BSS由20-编码。七个 dot/icm 基因，编码细菌细胞包膜中的大分子复合物。 Dot/Icm 系统对于细胞内生长和毒力来说是绝对必需的。由于多级冗余，约 300 点/Icm 基板对于这两种性状似乎都是可有可无的。因此，嗜肺军团菌 Dot/Icm 代表了治疗干预最可行的目标。尽管已经获得了大量关于组件的组装和功能的信息 Dot/Icm 系统仍然存在许多问题，该提案将跟进一些最新进展。 Dot/Icm T4BSS 包括发现 Dot/Icm 系统位于地球的两极。细菌和底物的极性输出需要通过这种特殊的分泌系统进行适当的 LCV（含有液泡的军团菌）的细胞内靶向第二个主要进展是确定与分泌伴侣结合的 DotL C 末端的结构。总体而言，这项研究通过冷冻电镜获得了该分泌装置的第一张图像。首先，建立嗜肺军团菌的机制。在巨噬细胞内生存和复制将提供更多关于它如何引起疾病的见解，并可能揭示用于药物治疗的新靶标其次，因为专门的分泌系统是。多种细菌病原体常用，获得有关嗜肺军团菌分泌物的知识该装置可能适用于理解其他病毒所使用的毒力分子机制。病原体，并可以作为预防或治疗许多不同疾病的基础。