Regulation of Host Defense by IRG Proteins

IRG 蛋白对宿主防御的调节

• 批准号: 8070511
• 负责人: GREGORY A TAYLOR
• 金额: $ 31.63万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8070511
• 关键词: Actins; Address; Appearance; Bacteria; Binding; Biochemical; Categories; Cell membrane; Communicable Diseases; Complex; Cytoskeleton; Data; Defect; Dependence; Family; Generations; Genetic Transcription; Goals; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Host Defense; Host resistance; Human; Immune system; Immunity; Interferon Type II; Interferons; Laboratories; Macrophage Colony-Stimulating Factor; Mediating; Membrane Lipids; Molecular; Mus; Mycobacterium tuberculosis; Natural Immunity; Pathway interactions; Phagosomes; Physiological; Play; Process; Protein Deficiency; Protein Family; Proteins; Protozoa; Publishing; Regulation; Research; Resistance; Role; Salmonella typhimurium; Site; Tertiary Protein Structure; Therapeutic Agents; Time; Toxoplasma gondii; Translations; antimicrobial drug; base; biodefense; cell motility; cytokine; gene cloning; killings; macrophage; mutant; novel; pathogen; prevent; protein complex; protein expression; public health relevance

DESCRIPTION (provided by applicant): Interferon (IFN)-gamma is a prominent activator of pathways that effect host defense against intracellular pathogens, including many category A, B, and C biodefense priority pathogens. The Immunity-related GTPases (IRG; also known as p47 GTPases) are a family of IFN-gamma-induced proteins that play critical roles in resistance to intracellular bacteria and protozoa, including Salmonella typhimurium and Toxoplasma gondii. Mice lacking certain IRG proteins have crippled host defense against these pathogens; further, macrophages isolated from the IRG-deficient mice display defects in phagosome processing and intracellular killing, as well as in cellular motility. However, the underlying mechanisms are unknown. Based on our published and preliminary data, we hypothesize the following: Hypothesis 1. IRG proteins form complexes among themselves - both homotypic and heterotypic - that regulate phagosome processing and macrophage motility. Hypothesis 2. IRG proteins in the GMS subfamily play dominant roles as regulators of the IRG proteins in the GKS subfamily. GMS proteins complex with specific GKS proteins to prevent their degradation, enabling subsequent GKS protein assembly in homotypic complexes at sites of contact between lipid membranes and the actin cytoskeleton, impacting phagosome processing and cell motility. We will address these hypotheses with the following: Aim 1. We will define homotypic and heterotypic IRG protein complexes that exist among specific GMS and GKS proteins in activated macrophages. We will determine the localization of the complexes, and the time frames in which they appear as related to cell motility and phagosome processing. We will determine the dependence on biochemical activity and protein domains on formation of the complexes. Aim 2. We will define the role of IRG GMS proteins in regulating IRG GKS proteins, and in coordinating IRG protein-mediated host defense functions. We will determine the effect of GMS protein deficiency on regulating GKS protein levels. Where levels are altered, we will determine whether GMS proteins impact GKS expression at the level of transcription, translation, and/or protein stability. We will determine the effect of IRG GMS protein-deficiency on the creation of homotypic IRG GKS protein complexes on the phagosome, and on the plasma membrane at the leading edge of the migrating macrophages. PUBLIC HEALTH RELEVANCE: This research will elucidate a fundamental mechanism that governs resistance to intracellular bacteria and protozoa. Our ultimate goals are the generation of broadly applicable therapeutic agents for human infectious disease and biodefense.

描述（由申请人提供）：干扰素（IFN）-Gamma是途径的突出激活因子，可影响宿主防御对细胞内病原体的影响，包括许多A类，B类和C Biodefense Priority病原体。与免疫性相关的GTPase（IRG；也称为p47 GTPase）是IFN-GAMMA诱导的蛋白质家族，在抗细胞内细菌和原生动物中起着至关重要的作用，包括鼠伤寒沙门氏菌和toxoplasma gondii。缺乏某些IRG蛋白质的小鼠对这些病原体的防御削弱了宿主的防御。此外，从IRG缺陷型小鼠中分离出的巨噬细胞在吞噬体加工和细胞内杀戮以及细胞运动中显示出缺陷。但是，基本机制尚不清楚。基于我们发布的和初步数据，我们假设以下内容：假设1。IRG蛋白质彼此之间形成复合物 - 同源性和异型型 - 调节吞噬体加工和巨噬细胞运动。假设2。GMS亚家族中的IRG蛋白作为GKS亚科中IRG蛋白的调节剂的主要作用。 GMS蛋白与特定GKS蛋白复合以防止其降解，从而在脂质膜和肌动蛋白细胞骨架之间接触部位的同型复合物中随后的GKS蛋白质组装，影响吞噬体处理和细胞运动。我们将使用以下内容解决这些假设：AIM 1。我们将定义特定的GMS和GKS蛋白之间存在于活化巨噬细胞中的特定GMS和GKS蛋白之间的同型和异型IRG蛋白复合物。我们将确定复合物的定位，以及它们与细胞运动和吞噬体处理相关的时间范围。我们将确定对生化活性和蛋白质结构域对复合物形成的依赖性。 AIM 2。我们将定义IRG GMS蛋白在调节IRG GKS蛋白以及协调IRG蛋白介导的宿主防御功能方面的作用。我们将确定GMS蛋白缺乏对调节GKS蛋白水平的影响。在改变水平的地方，我们将确定GMS蛋白是否会影响转录，翻译和/或蛋白质稳定性水平的GKS表达。我们将确定IRG GMS蛋白质缺陷对吞噬体上同型IRG GKS蛋白复合物以及在迁移巨噬细胞前缘的质膜上产生的影响。 公共卫生相关性：这项研究将阐明一种基本机制，该机制控制了对细胞内细菌和原生动物的抗性。我们的最终目标是生成针对人类传染病和生物性疾病的广泛适用的治疗剂。