Modulation of Host Vesicle Trafficking by Legionella pneumophila

描述（由申请方提供）：嗜肺军团菌是军团菌病的病原体，是一种细胞内病原体。其致病性的关键是Dot/Icm IV型分泌系统，该系统将大量细菌效应物易位到宿主细胞中。这些效应子调节多种宿主细胞过程以产生允许军团菌细胞内生长的内质网（ER）衍生的细胞器。我们最近发现，这样的效应器之一，称为SidJ起着重要的作用，在生物合成的复制军团菌含空泡（LCV）和损失SidJ的结果在招聘的ER蛋白的LCV的时间延迟。进一步的研究表明，SidJ是一种蛋白磷酸酶，与Sec 31相互作用并使Sec 31去磷酸化，Sec 31是COPII包被囊泡外壳复合物的主要亚基。我们的工作假设是，SidJ，通过与其他效应物协调，重定向COPII包被的囊泡的运输到细菌吞噬体。本项目的目标是利用遗传学、生物化学和细胞生物学方法来表征军团菌感染中SidJ及其蛋白磷酸酶活性。我们的主要工作是：1）分析SidJ与Sec 31之间的相互作用及其对宿主分泌途径的影响。2)研究SidJ-Sec 31相互作用对COPII包被囊泡形成的功能后果。3)与SidJ协同作用的效应子的鉴定和表征。这项研究的结果将有助于新兴的细胞微生物学领域和细胞生物学领域，特别是COPII组分的蛋白磷酸化在调节囊泡运输中的作用。这些研究也将扩大我们的研究能力，从而使我们能够建立一个更广泛的项目研究计划。K 02奖将使我能够投入更多的努力，通过探索和获取在这个多学科领域未来成功所需的背景知识和新技术来发展我的研究事业。 相关性：由于其潜在的致命性，嗜肺军团菌感染是一个公共卫生问题。我们的研究可以为预防和/或治疗提供新的策略。此外，了解受这种细菌影响的哺乳动物细胞过程可能会为我们研究与这些过程异常相关的其他疾病提供线索。 项目叙述：嗜肺军团菌感染通常导致致命性肺炎的发展。此外，对该菌的研究也有助于我们对其他胞内病原菌的认识。嗜肺菌和这些感染因子共享许多致病机制。

DESCRIPTION (provided by applicant): Legionella pneumophila, the etiological agent of Legionnaires' disease is an intracellular pathogen. Essential to its pathogenicity is the Dot/Icm type IV secretion system that translocates a large number of bacterial effectors into host cell. These effectors modulate multiple host cell processes to create an endoplasmic reticulum (ER) derived organelle permissive for Legionella intracellular growth. We recently found that one of such effectors called SidJ plays an important role in the biogenesis of replicative Legionella-containing vacuoles (LCVs) and loss of SidJ results in a temporal delay in the recruitment of ER proteins to the LCVs. Further studies indicate that SidJ is a protein phosphatase that interacts with and dephosphorylates Sec31, the major subunit of the outer shell complexes of the COPII-coated vesicles. Our working hypothesis is that SidJ, by coordinating with other effectors, redirects the trafficking of COPII-coated vesicles to the bacterial phagosomes. The goal of this project is to characterize SidJ and its protein phosphatase activity in Legionella infection using genetic, biochemical and cell biological approaches. We propose to: 1) Analyzing the interactions between SidJ and Sec31 and the effect of SidJ on host secretory pathways. 2) Studying the functional consequence of SidJ-Sec31 interaction on COPII coated vesicle formation. 3) Identification and characterization of effectors that function synergistically with SidJ. Results from this study will contribute to the emerging field of cellular microbiology and to the field of cell biology, particularly the roles of protein phosphorylation of COPII components in the regulation of vesicle trafficking. These studies will also expand our research capacity, thus allowing us to establish a research program with a broader spectrum of projects. A K02 award would allow me to invest more effort to develop my research career by exploring and acquiring background knowledge and new techniques necessary for future success in this multidisciplinary field. Relevance: Because of its potential fatality, infection by Legionella pneumophila is a concern of public health. Our study can provide novel strategies for its prevention and/or treatment. Furthermore, understanding of mammalian cell processes affected by this bacterium could lead to clues in our study of other diseases associated with abnormality of these processes. Project Narrative: Infection by Legionella pneumophila often leads to the development of a fatal form of pneumonia. In addition, study on this bacterium could share light on our understanding of other intracellular pathogens because L. pneumophila and these infectious agents share many pathogenic mechanisms.