Protein Interactions in Type III Secretion in Y. pestis

鼠疫耶尔森氏菌 III 型分泌物中的蛋白质相互作用

• 批准号: 6574729
• 负责人: Matthew L. Nilles
• 金额: $ 51.38万
• 依托单位: UNIVERSITY OF NORTH DAKOTA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2008-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6574729
• 关键词: Yersinia pestis; bacterial proteins; circular dichroism; gel filtration chromatography; matrix assisted laser desorption ionization; plasmids; protein localization; protein protein interaction; protein structure function; secretion; site directed mutagenesis

DESCRIPTION (Provided by applicant): Yersinia pestis, the causative agent of Plague, harbors a -71 KB plasmid that encodes many virulence-related proteins. Among the pCDl-encoded genes are genes specifying for the construction of a type III secretion system and the genes for the secreted effector proteins (collectively termed Yops). Type III secretion systems allow pathogenic bacteria to specifically translocate effectors into eukaryotic cells for the pathogen's benefit. The Yops exert their effects on targeted eukaryotic cells that results in a blockage of phagocytosis by immune cells. This effect allows Y. pestis to remain extracellular during the course of an infection. In Y. pestis the activity of the type III system is controlled by environmental stimuli, in vitro secretion is stimulated by the removal of calcium ions. In vivo Yops translocation is triggered by contact with eukaryotic cells. Appropriate control of type III secretion is required for the disease process as mutants defective in control are avirulent. Control of type III secretion relies on both positive and negative control circuits. LcrG and LcrV are two proteins whose interaction is required to control type III secretion in Y. pestis. LcrV is required to activate secretion while LcrG is required to inactivate secretion. Their interaction provides a linkage between positive and negative regulation in type III secretion control. The mechanism responsible for their controlling effects are largely unknown, although progress has been made. Published studies have shown that the interaction of LcrG and LcrV is required to control secretion. Additionally, a separate study demonstrated that a ratio of LcrV to LcrG, favoring LcrV, is required to activate secretion. Clearly, more work is needed to define the roles of LcrG and LcrV in the activation of secretion. Specifically, in this proposal we shall: Aim 1. Define structure-function relationships within LcrG relating to LcrV interaction and secretion-blocking. Aim 2. Screen for other proteins that may interact with LcrG. Aim 3. Refine the subcellular localization of LcrG. Aim 4. Examine mechanisms that alter LcrG levels relative to LcrV. Type III secretion systems have emerged recently as a common theme in the pathogenic mechanism of many gram-negative bacterial pathogens. Work in the yersiniae has been at the forefront of research on the characterization and function of type III mechanisms. An understanding of how these systems are controlled should lead to a deeper understanding of the intimate and dynamic interactions between pathogens and their hosts.

描述（由申请人提供）：鼠疫的病因耶尔西尼亚·佩斯蒂斯（Yersinia Pestis），含有编码许多与毒力相关蛋白质的-71 kb质粒。在PCDL编码的基因中，有指定的基因，用于构建III型分泌系统和分泌效应蛋白（统称为YOPS）的基因。 III型分泌系统使致病细菌可以将效应子特异性地将效应子转移到真核细胞中，以便病原体的益处。 YOP对靶向的真核细胞发挥作用，从而导致免疫细胞吞噬作用阻塞。这种效果使鼠疫在感染过程中保持细胞外。在Y. Pestis中，III型系统的活性受环境刺激的控制，通过去除钙离子来刺激体外分泌。体内YOP易位是通过与真核细胞接触而触发的。 疾病过程需要适当控制III型分泌，因为缺陷在控制中的突变体是无毒的。对III型分泌的控制依赖于阳性对照电路。 LCRG和LCRV是两种蛋白质，其相互作用需要控制Y. Pestis中的III型分泌。 需要LCRV激活分泌，而LCRG需要灭活分泌。它们的相互作用在III型分泌控制中提供了正调节和负调节之间的联系。尽管取得了进展，但导致其控制作用的机制在很大程度上是未知的。已发表的研究表明，控制分泌需要LCRG和LCRV的相互作用。此外，一项单独的研究表明，LCRV与LCRG的比率（有利于LCRV）激活分泌需要。显然，需要更多的工作来定义LCRG和LCRV在分泌激活中的作用。具体而言，在此提案中，我们将：目标1。定义与LCRV相互作用和分泌阻滞有关的LCRG内的结构功能关系。目标2。其他可能与LCRG相互作用的蛋白质的屏幕。目标3。完善LCRG的亚细胞定位。目标4。检查相对于LCRV改变LCRG水平的机制。 III型分泌系统最近已成为许多革兰氏阴性细菌病原体的致病机理中的共同主题。在耶尔森氏菌的工作一直是关于III型机制的表征和功能的研究的最前沿。对这些系统的控制方式的理解应导致对病原体及其宿主之间的亲密和动态相互作用的深入了解。