Novel rhoptry effector proteins in Toxoplasma host-pathogen interaction

弓形虫宿主-病原体相互作用中的新型棒状体效应蛋白

• 批准号: 8229898
• 负责人: Peter John Bradley
• 金额: $ 23.1万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-15 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8229898
• 关键词: Acquired Immunodeficiency Syndrome; Acute; Address; Affinity; Ala-Trp-Arg-His-Pro-Gln-Phe-Gly-Gly; Blood; Cell physiology; Cells; Central Nervous System Diseases; Chronic; Complex; Congenital Abnormality; Cytoplasm; Cytoplasmic Granules; Cytosol; Destinations; Disease; Family; Genes; Hand; Human; Immune response; Immunocompromised Host; In Vitro; Individual; Infection; Injection of therapeutic agent; Invaded; Knock-out; Mammalian Cell; Masks; Mediating; Microarray Analysis; Monoclonal Antibodies; Mus; Names; Needles; Nomenclature; Organelles; Organism; Parasites; Pathway interactions; Patients; Penetration; Phenotype; Phosphotransferases; Play; Population; Positioning Attribute; Process; Proteins; Proteomics; Role; Series; Shapes; Signal Pathway; Staging; System; Toxoplasma; Toxoplasma gondii; Virulence; Work; experience; in vivo; insight; knockout gene; neonate; novel; obligate intracellular parasite; pathogen; protein function; response; rhoptry; success; tissue tropism; tool; trafficking

DESCRIPTION (provided by applicant): Toxoplasma gondii is an obligate intracellular parasite that causes severe central nervous system disorders in immunocompromised individuals and birth defects in congenitally infected neonates. Intracellular survival of these organisms is dependent on the ability to invade their host cell, establish a replication-permissive niche, and avoid host cell defenses. The secretory rhoptries have emerged as a key organelle that regulates both invasion and hijacking of host cell functions. For hijacking host functions, the rhoptries inject a burst of proteins into the host cell cytoplasm that can be trafficked to distinct compartments within the infected cell and directly target host pathways. The importance of these host "effector" proteins is exemplified by a family of rhoptry kinases that are injected and play critical roles in modulating host signaling pathways and regulating parasite virulence. In addition to ROP kinases, the rhoptries inject an array of other effector proteins that are of unknown function. Most of these proteins lack homology to known proteins or identifiable domains and are unique to Toxoplasma and closely related parasites. We have identified a panel of these novel rhoptry effectors and developed gene knockouts in the biologically relevant type II strain parasites for their study. In this proposal, we will determine the role of these novel effector proteins in regulating host functions. Specifically, we will determine the host response to ?effector strains in vitro using host microarray analysis and in vivo by assessing virulence, tissue tropism, and bradyzoite formation in mice. We will additionally use exogenous expression of tandem affinity tagged effector proteins in host cells to determine their destination and identify host targets. Together, these complementary approaches promise to reveal novel mechanistic insights into how Toxoplasma uses this unique set of effector proteins to modulate its mammalian host cell. PUBLIC HEALTH RELEVANCE: Toxoplasma gondii is an intracellular parasite that infects up to a third of the world's human population and causes serious disease in immunocompromised (AIDS) patients and congenitally-infected neonates. Toxoplasma secretes an array of factors from an organelle named the rhoptries that enable it to invade and hijack its host cell. This project is focused determining the function of a novel group of rhoptry effector proteins by examining the host response to gene knockout parasites and identifying host proteins that interact with these novel effectors.

描述（由申请方提供）：弓形虫是一种专性细胞内寄生虫，可导致免疫功能低下个体的严重中枢神经系统疾病和先天性感染新生儿的出生缺陷。这些生物体的细胞内存活依赖于侵入其宿主细胞、建立允许复制的小生境和避免宿主细胞防御的能力。分泌棒状体已经成为调节入侵和劫持宿主细胞功能的关键细胞器。为了劫持宿主功能，棒状体将蛋白质注入宿主细胞质中，这些蛋白质可以被运输到感染细胞内的不同隔室并直接靶向宿主途径。这些宿主“效应物”蛋白的重要性由棒状体激酶家族例证，棒状体激酶被注射并且在调节宿主信号传导途径和调节寄生虫毒力中发挥关键作用。 除了ROP激酶，棒状体还注入一系列功能未知的其他效应蛋白。这些蛋白质中的大多数与已知蛋白质或可识别结构域缺乏同源性，并且是弓形虫和密切相关的寄生虫所特有的。我们已经确定了一组这些新的棒状效应子，并在生物学相关的II型菌株寄生虫中开发了基因敲除。在这个提议中，我们将确定这些新的效应蛋白在调节宿主功能中的作用。具体来说，我们将确定主机响应？在体外使用宿主微阵列分析和在体内通过评估小鼠中的毒力、组织嗜性和缓殖子形成来研究效应菌株。我们还将使用串联亲和标记效应蛋白在宿主细胞中的外源表达来确定它们的目的地并鉴定宿主靶标。总之，这些互补的方法有望揭示弓形虫如何使用这套独特的效应蛋白来调节其哺乳动物宿主细胞的新机制。 公共卫生关系：弓形虫是一种细胞内寄生虫，感染了世界上三分之一的人口，并在免疫功能低下（AIDS）患者和先天性感染的新生儿中引起严重疾病。弓形虫从一种名为棒状体的细胞器中分泌一系列因子，使其能够入侵并劫持宿主细胞。该项目的重点是确定一组新的棒状效应蛋白的功能，通过检查宿主对基因敲除寄生虫的反应，并确定与这些新的效应蛋白相互作用的宿主蛋白。