Salmonella SopA is a functional mimicry of eukaryotic E3 protein ubiquitin ligase

沙门氏菌 SopA 是真核 E3 蛋白泛素连接酶的功能模拟物

• 批准号: 7448037
• 负责人: DAOGUO ZHOU
• 金额: $ 22.88万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-08 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7448037
• 关键词: Bacteria; Biochemical; Cell Extracts; Cell Survival; Cell physiology; Cells; Classification; Clinical; Data; Developed Countries; Developing Countries; Disease; Domestic Animals; Drug Design; Epithelial; Epithelial Cells; Foundations; Gastroenteritis; Goals; Human; Infection; Inflammatory Response; Inflammatory disease of the intestine; Longitudinal Studies; Lysine; Mammalian Cell; Mediating; Medical; Molecular; Multi-Drug Resistance; Pathway interactions; Play; Production; Protein Secretion; Proteins; Role; Salmonella; Salmonella enterica; Salmonella infections; System; Therapeutic; Type III Secretion System Pathway; Ubiquitin; Ubiquitination; Virulence; Work; cellular targeting; chemokine; enteritis; foodborne; interest; migration; mimicry; neutrophil; public health relevance; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Salmonella enterica serovar Typhimurium causes mild gastroenteritis and more severe systematic infections in both humans and domestic animals. It encodes two specialized type III protein secretion systems that are required for bacterial invasion into epithelial cells, for survival inside the host cells, and for the induction of gastroenteritis. Through the type III secretion system, Salmonella injects a panel of bacterial effector proteins to exploit the host cell function to induce intestinal inflammation. Previous work has shown that SopA, one of the type III effectors, plays a key role in chemokine production, induction of enteritis, and is required for efficient polymorphonuclear leukocytes (PMN) trans-epithelial migration. Our preliminary data demonstrated that SopA is an E3 ubiquitin ligase. We also found that the SopA E3 ligase activity is involved in Salmonella- induced PMN transepithelial migration. Furthermore, we showed that SopA is capable of ubiquitinating protein(s) from uninfected mammalian cell extracts. In addition, we demonstrated that SopA is ubiquitinated by HsRMA1, a host ubiquitin E3 ligase. The discovery of the Salmonella E3 ubiquitin ligase, SopA, has provided us with a unique opportunity to study SopA function and to help unravel the molecular and biochemical mechanisms by which Salmonella and SopA induce intestinal inflammation and enteritis. My working hypothesis is that SopA ubiquitinates bacterial and/or host substrate protein(s), which are involved in Salmonella-induced inflammatory responses. We seek to identify bacterial and/or host proteins that are ubiquitinated by Salmonella SopA. In this proposal, we plan to: 1) determine the ubiquitin lysine linkages in SopA and HsRMA1-mediated ubiquitination; 2) identify bacterial or host protein(s) that are ubiquitinated by Salmonella SopA. SopA-ubiquitinated proteins identified from this study will lay the foundation for more long- term studies aimed at understanding how SopA induces gastroenteritis and how Salmonella induces intestinal inflammation in humans. PUBLIC HEALTH RELEVANCE: the understanding gained by our long-standing interest in studying Salmonella, salmonellosis continues to pose worldwide medical concerns and remains the number one cause of food-borne diseases even in developed countries. How Salmonella cause gastroenteritis is poorly understood. The identification of host cellular targets of Salmonella virulence proteins will aid clinical therapeutic drug designs and treatment of multidrug-resistant bacteria. Results from this study will help us understand how Salmonella induces intestinal inflammation in humans.

描述（由申请人提供）：鼠伤寒沙门氏菌引起人类和家畜轻度胃肠炎和更严重的系统性感染。它编码两种特殊的 III 型蛋白分泌系统，这些系统是细菌侵入上皮细胞、在宿主细胞内生存以及诱导胃肠炎所必需的。通过 III 型分泌系统，沙门氏菌注入一组细菌效应蛋白，利用宿主细胞功能诱导肠道炎症。先前的研究表明，SopA是III型效应子之一，在趋化因子的产生、肠炎的诱导中发挥着关键作用，并且是有效的多形核白细胞（PMN）跨上皮迁移所必需的。我们的初步数据表明 SopA 是一种 E3 泛素连接酶。我们还发现 SopA E3 连接酶活性参与沙门氏菌诱导的 PMN 跨上皮迁移。此外，我们表明 SopA 能够泛素化未受感染的哺乳动物细胞提取物中的蛋白质。此外，我们证明 SopA 被 HsRMA1（一种宿主泛素 E3 连接酶）泛素化。沙门氏菌E3泛素连接酶SopA的发现为我们提供了研究SopA功能的独特机会，并帮助揭示沙门氏菌和SopA诱导肠道炎症和肠炎的分子和生化机制。我的工作假设是 SopA 泛素化细菌和/或宿主底物蛋白，这些蛋白参与沙门氏菌诱导的炎症反应。我们寻求鉴定被沙门氏菌 SopA 泛素化的细菌和/或宿主蛋白。在本提案中，我们计划：1）确定SopA和HsRMA1介导的泛素化中的泛素赖氨酸连接； 2) 鉴定被沙门氏菌 SopA 泛素化的细菌或宿主蛋白。这项研究中鉴定出的 SopA 泛素化蛋白将为更长期的研究奠定基础，这些研究旨在了解 SopA 如何诱发胃肠炎以及沙门氏菌如何诱发人类肠道炎症。 公共卫生相关性：根据我们对沙门氏菌研究的长期兴趣所获得的认识，沙门氏菌病继续引起世界范围的医学关注，并且即使在发达国家也仍然是食源性疾病的头号原因。人们对沙门氏菌如何引起胃肠炎知之甚少。沙门氏菌毒力蛋白宿主细胞靶标的鉴定将有助于临床治疗药物设计和多重耐药细菌的治疗。这项研究的结果将帮助我们了解沙门氏菌如何诱发人类肠道炎症。