Orientia tsutsugamushi modulation of host cell ubiquitination machinery

恙虫病东方体对宿主细胞泛素化机制的调节

基本信息

批准号：
8720687
负责人：
Jason A Carlyon
金额：
$ 19.06万
依托单位：
VIRGINIA COMMONWEALTH UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-08-14 至 2016-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8720687
关键词：
Acute Afghanistan Ankyrin Repeat Architecture Asia Bacteria Bacterial Proteins Binding Binding Proteins Blood Vessels Boxing Case Study Cell Line Cell physiology Cells Cessation of life Chiggers Communicable Diseases Complex Data Disease Endothelial Cells Extravasation F Box Domain F-Box Motifs F-Box Proteins Fever Funding Genes Immune Sera Infection Invaded Knowledge Lead Mediating Middle East Mites Morbidity - disease rate Nature Orientia tsutsugamushi Pakistan Pathogenesis Proteins Risk Role SKP Cullin F-Box Protein Ligases Scrub Typhus Soldier Structure Testing Ubiquitin Ubiquitination Vietnam Conflict Viral Virus Work World War II cell type in vivo killings macrophage mortality multicatalytic endopeptidase complex neglect neutrophil novel pathogen protein expression protein protein interaction public health relevance research study tissue/cell culture ubiquitin ligase

项目摘要

DESCRIPTION (provided by applicant): Scrub typhus is a neglected disease that threatens the 1 billion inhabitants of the Asia-Pacific rim and causes 1 million new infections annually. Its mortality rate can be as high as 50%. The disease was a significant cause of morbidity in World War II and the Vietnam conflict and presently threatens U.S. soldiers serving in the Middle East. The causative agent is the chigger-transmitted obligate intracellular bacterium, Orientia tsutsugamushi, which colonizes microvascular endothelial cells, macrophages, and neutrophils. The proposed work will advance understanding of how Orientia facilitates its survival in its diverse host cell types, a subject that has long-remained a metaphoric "black box". The ankyrin repeat is the most common protein-protein interaction motif in nature. Many intracellular bacterial and viral pathogens translocate ankyrin repeat-containing proteins (Anks) into eukaryotic host cells. The Anks interact with target proteins to modulate host cell functions. O. tsutsugamushi encodes 38 Anks, several of which also carry another eukaryotic-like motif, the F-box, in their C-termini. We refer to these as Ank/F-box proteins. Eukaryotic F-boxes bind SKP1, a part of the SCF1 ubiquitin ligase complex, which catalyzes the transfer of ubiquitin onto proteins to target them for degradation in the proteasome. The bipartite structure of Ank/F-box proteins conceivably enables them to bind protein substrates via their Ank domains and, using their F-box motifs, bind SKP1 to direct SCF1-mediated ubiquitination and subsequent proteasomal degradation of the substrates. We discovered that 5 of the 8 ank genes that Orientia expresses as it establishes infection in tissue culture cells encode Ank/F-box proteins. In Aim 1, we will evaluate our hypothesis that the Ank/F-box proteins interact with SKP1 to promote SCF1- mediated ubiquitination of host cell proteins. We will also identify the proteins that become ubiquitinated as a result of interacting with Ank/F-box proteins. Given its extensive Ank repertoire, we hypothesize that Orientia expresses specific Anks to establish infection in endothelial cells, macrophages, and neutrophils. In Aim 2, we will close an important knowledge gap by identifying the Anks that the pathogen expresses as it establishes infection in each of the 3 biologically relevant host cells.

描述（由申请人提供）：恙虫病是一种被忽视的疾病，威胁着亚太地区 10 亿居民，每年造成 100 万人新感染。它是死亡率可高达50%。这种疾病是第二次世界大战和越南冲突中发病的一个重要原因，目前威胁着在中东服役的美国士兵。病原体是恙螨传播的专性细胞内细菌东方恙虫病，它定殖于微血管内皮细胞、巨噬细胞和中性粒细胞。这项拟议的工作将增进对东方体如何促进其在不同宿主细胞类型中生存的理解，这个课题长期以来一直是一个隐喻的“黑匣子”。锚蛋白重复序列是自然界中最常见的蛋白质-蛋白质相互作用基序。许多细胞内细菌和病毒病原体将含有锚蛋白重复序列的蛋白质 (Anks) 易位到真核宿主细胞中。 Anks 与靶蛋白相互作用来调节宿主细胞功能。恙虫病 O. tsutsugamushi 编码 38 个 Anks，其中一些在其 C 末端还携带另一个类似真核生物的基序，即 F-box。我们将这些称为 Ank/F-box 蛋白。真核 F-box 结合 SKP1，SKP1 是 SCF1 泛素连接酶复合物的一部分，催化泛素转移到蛋白质上，以靶向它们在蛋白酶体中降解。 Ank/F-box 蛋白的二分结构可能使它们能够通过其 Ank 结构域结合蛋白质底物，并利用其 F-box 基序结合 SKP1 来指导 SCF1 介导的泛素化和随后的底物蛋白酶体降解。我们发现 Orientia 在组织培养细胞中建立感染时表达的 8 个 ank 基因中有 5 个编码 Ank/F-box 蛋白。在目标 1 中，我们将评估我们的假设，即 Ank/F-box 蛋白与 SKP1 相互作用，促进 SCF1 介导的宿主细胞蛋白泛素化。我们还将鉴定因与 Ank/F-box 蛋白相互作用而被泛素化的蛋白。鉴于其广泛的 Ank 库，我们假设 Orientia 表达特定的 Ank 来在内皮细胞、巨噬细胞和中性粒细胞中建立感染。在目标 2 中，我们将通过识别病原体在 3 个生物学相关宿主细胞中建立感染时表达的 Anks 来弥补重要的知识差距。