Ehrlichia TRP120 HECT E3 ubiquitin ligase modulation of host cell pathways

埃里希体 TRP120 HECT E3 泛素连接酶对宿主细胞途径的调节

基本信息

批准号：
10248423
负责人：
JERE W MCBRIDE
金额：
$ 19.75万
依托单位：
UNIVERSITY OF TEXAS MED BR GALVESTON
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-01 至 2023-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10248423
关键词：
Address Apoptotic Bacteria CUL1 gene Cell Proliferation Cell Survival Cell physiology Cells Complex Critical Pathways Development Down-Regulation Ehrlichia Ehrlichia chaffeensis Ehrlichiosis Enhancers Etiology Eukaryotic Cell F Box Domain F-Box Proteins FBXW7 gene Feasibility Studies Gene Expression Genetic Transcription Genome Goals Host Defense Human Immune In Vitro Infection Investigation Knowledge Life Ligase Lysine Mediating Modeling Molecular Mononuclear Pathway interactions Phagocytes Polycomb Polyubiquitination Post-Translational Protein Processing Process Proteins Research Ring Finger Domain Role Signal Transduction Site Small Interfering RNA System Tandem Repeat Sequences Therapeutic Transcription Repressor Transducin Tumor Suppressor Proteins Ubiquitin Ubiquitination WD Repeat antimicrobial base c-myc Genes cellular targeting enolase in vivo knock-down new therapeutic target notch protein novel novel therapeutic intervention pathogen programs protein function protein protein interaction tick-borne ubiquitin ligase ubiquitin-protein ligase

项目摘要

Project Summary/Abstract Ehrlichia chaffeensis (E. ch.) is a gram-negative, obligately intracellular bacterium and etiologic agent of human monocytotropic ehrlichiosis (HME), an emerging, life-threatening, tick-borne zoonosis. E. ch. preferentially infects mononuclear phagocytes and survives intracellularly by subverting innate immune defenses mediated in part by tandem repeat protein (TRP) effectors. TRPs are secreted intracellularly during infection via a type-1 secretion system where they interact in a context-dependent manner with a diverse array of host cell proteins involved in essential cellular processes. The molecular features that determine the continuum of protein-protein interactions that occur during host-pathogen interplay, including those attributed to ehrlichial TRPs, are known to involve posttranslational modifications (PTMs). The scientific premise of this proposal is based on our previous research demonstrating that the E. ch. infection is dependent on exploitation of host PTM pathways for infection, the discovery that E. ch.TRP120 moonlights as a HECT-type E3 ubiquitin (Ub) ligase that tags host proteins for Ub-mediated degradation, identification of novel TRP120-host protein interactions, enhancement of infection through iRNA knockdown of selected TRP120 targets, and demonstration that Wnt and Notch pathways are critical for ehrlichial infection. The long-term goal of this research is to understand the role of host- and pathogen- derived PTMs in host cell reprogramming and infection by E. ch. The objectives of this proposal are to determine the functional role of TRP120 HECT E3 Ub ligase activity during infection, demonstrate TRP120 ubiquitination and degradation of specific host cell targets, and to further expand and define the repertoire of TRP120 Ub ligase substrates. We hypothesize that E. ch. TRP120 HECT E3 ligase modulates host cell signaling and transcriptional repressors via a Ub-mediated degradation mechanism to promote host cell survival and ehrlichial infection. Aim 1 is to determine the role of TRP120 HECT E3 Ub ligase in degrading host cell transcription and signaling regulators; Aim 2 will identify novel TRP120 HECT E3 Ub ligase substrates degraded during infection. This research is significant because it will addresses how intracellular pathogens, particularly those with small genomes and a limited number of effector proteins, interface with eukaryotic cells via PTMs and use pathogen- encoded Ub ligases to manipulate complex and evolutionarily conserved host cell pathways to promote infection. We have established an excellent model to investigate the mechanisms whereby intracellular pathogens influence the stability of cellular regulators though pathogen-encoded Ub ligases. Understanding the interactions between E. ch. HECT-type E3 Ub ligases and host processes/pathways will further define TRP moonlighting roles in pathobiology, and how pathogens mimic eukaryotic protein function to exploit host cell pathways for their benefit.

项目概要/摘要恰菲埃里希体 (E. ch.) 是一种革兰氏阴性、专性细胞内细菌，是人类感染的病原体。单核细胞嗜埃利希体病 (HME)，一种新出现的危及生命的蜱传人畜共患病。 E.ch.优先地感染单核吞噬细胞并通过破坏介导的先天免疫防御在细胞内存活部分由串联重复蛋白（TRP）效应子组成。 TRP 在感染过程中通过 1 型细胞分泌到细胞内分泌系统，它们以上下文相关的方式与多种宿主细胞蛋白相互作用参与重要的细胞过程。决定蛋白质-蛋白质连续体的分子特征宿主与病原体相互作用期间发生的相互作用，包括归因于埃利希体 TRP 的相互作用，是已知的涉及翻译后修饰（PTM）。这个提议的科学前提是基于我们之前的研究表明，E. ch。感染取决于宿主 PTM 感染途径的利用，发现 E. ch.TRP120 兼职作为 HECT 型 E3 泛素 (Ub) 连接酶，标记宿主蛋白 Ub 介导的降解、新型 TRP120-宿主蛋白相互作用的鉴定、感染的增强通过 iRNA 敲低选定的 TRP120 靶标，并证明 Wnt 和 Notch 通路对于埃立克体感染至关重要。这项研究的长期目标是了解宿主和病原体的作用宿主细胞重编程和大肠杆菌感染中衍生的 PTM。该提案的目标是确定 TRP120 HECT E3 Ub 连接酶活性在感染过程中的功能作用，证明 TRP120 泛素化和特定宿主细胞靶标的降解，并进一步扩展和定义 TRP120 Ub 连接酶的库基材。我们假设 E. ch。 TRP120 HECT E3 连接酶调节宿主细胞信号传导和转录抑制子通过泛素介导的降解机制促进宿主细胞存活和埃利希体感染。目的 1是确定TRP120 HECT E3 Ub连接酶在降解宿主细胞转录和信号传导中的作用监管机构；目标 2 将鉴定感染过程中降解的新型 TRP120 HECT E3 Ub 连接酶底物。这这项研究意义重大，因为它将解决细胞内病原体，特别是那些具有小分子的病原体如何基因组和有限数量的效应蛋白，通过 PTM 与真核细胞相互作用，并使用病原体编码 Ub 连接酶来操纵复杂且进化上保守的宿主细胞途径以促进感染。我们建立了一个优秀的模型来研究细胞内病原体的机制通过病原体编码的 Ub 连接酶影响细胞调节因子的稳定性。了解交互作用 E.ch.之间。 HECT 型 E3 Ub 连接酶和宿主过程/途径将进一步定义 TRP 兼职病理学中的作用，以及病原体如何模仿真核蛋白质功能以利用宿主细胞途径来发挥其作用益处。