Suppression of innate immunity by an ADP-ribosyltransferase type III effector

ADP-核糖基转移酶 III 型效应子对先天免疫的抑制

• 批准号: 8197564
• 负责人: JAMES Robert ALFANO
• 金额: $ 35.55万
• 依托单位: UNIVERSITY OF NEBRASKA LINCOLN
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-12-15 至 2013-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8197564
• 关键词: ADP Ribose Transferases; ADP ribosylation; Active Sites; Affect; Animals; Arabidopsis; Award; Binding; Biochemical; Biological; Chloroplasts; Cholera Toxin; Data; Disease; Eukaryota; Gene Expression Profile; Genes; Glycine; Grant; Immune response; Immune system; In Vitro; Inflammatory; Journals; Mammals; Manuscripts; Mass Spectrum Analysis; Metabolism; Microbe; Mission; Modeling; Molecular; Natural Immunity; Nature; Pathogenesis; Plant Proteins; Plants; Play; Predisposition; Principal Investigator; Production; Protein Secretion; Proteins; Pseudomonas syringae; Publishing; RNA; RNA Splicing; RNA-Binding Proteins; Research; Research Personnel; Resources; Role; Shigella flexneri; System; Tomatoes; Toxin; Type III Epithelial Receptor Cell; United States National Institutes of Health; Update; base; cost efficient; cytokine; interest; mutant; novel; pathogen; programs; research study; response

DESCRIPTION (provided by applicant): The eukaryotic innate immune system represents an important barrier that pathogens need to circumvent in order to cause disease. Several components of this system are conserved in eukaryotes. Recently, bacterial pathogen effectors that are injected into host cells by type III protein secretion systems (TTSSs) have been shown to be capable of suppressing innate immunity in eukaryotes. The bacterial plant pathogen Pseudomonas syringae is dependent on a TTSS to cause disease on plants. The P. s. pv. tomato DC3000 effector gene hopU1 resembles ADP ribosyltransferases (ADP-RTs) genes. These genes encode some of the best understood toxins in bacterial pathogens of animals (e. g., cholera toxin). Preliminary data within this proposal show that HopU1 is an active ADP-RT and that it ADP-riboslylates several plant proteins. Mass spectrometry determined that chloroplast and glycine-rich RNA-binding proteins acted as in vitro substrates for HopU1. These are novel substrates for ADP-RTs. Moreover, HopU1 has the ability to suppress several responses of the plant innate immune system in a manner that is dependent on its ADP-RT active site. An Arabidopsis mutant lacking one HopU1 substrate, AtGRP7, displayed enhanced susceptibility to P. syringae suggesting that it is a component of innate immunity. AtGRP7 is a glycine-rich RNA-binding protein, which suggests this pathogen targets proteins involved in RNA metabolism to suppress innate immunity. The central hypothesis of the proposed experiments is that AtGRP7 and perhaps other targets of the HopU1 ADP-RT type III effector are components of innate immunity. Several of the experiments seek to elucidate the role AtGRP7 plays in innate immunity using biochemical and molecular biological approaches. The P. syringae-Arabidopsis pathosystem is an excellent model to study the innate immune system because of the resources available, the similarities between innate immune systems between eukaryotes, and the cost efficient research. These experiments will contribute to a fundamental understanding of the molecular mechanism of bacterial pathogenesis and innate immunity. The Specific Aims are the following: (1) Determine the molecular consequence of ADP- ribosylation on the function of AtGRP7 and elucidate the role this protein plays in innate immunity; (2) Identify additional substrates of HopU1 and verify their involvement in innate immunity; (3) Analyze the affect that HopU1 has on host-microbe interactions. Project Narrative: Identifying the eukaryotic targets for the P. syringae HopU1 ADP-ribosyltransferase will contribute to our understanding of bacterial pathogenesis and will likely reveal important components of the innate immune system. One HopU1 target belongs to a large group of proteins called glycine-rich RNA binding proteins, which are not well understood, and this research will likely increase our understanding of these proteins. Because there are considerable similarities between the innate immune systems in plants and mammals we expect that our findings will be relevant to the mission of the NIH and be broadly interesting to researchers studying molecular mechanisms of bacterial pathogenesis and innate immunity.

描述（由申请人提供）：真核先天免疫系统是病原体需要绕过的重要屏障，以引起疾病。该系统的几个组成部分在真核生物中是保守的。最近，通过III型蛋白分泌系统（TTSSs）注入宿主细胞的细菌病原体效应物已被证明能够抑制真核生物的先天免疫。植物病原菌丁香假单胞菌依赖TTSS对植物致病。p.s. pv。番茄DC3000效应基因hopU1类似于ADP核糖基转移酶（ADP- rts）基因。这些基因编码动物细菌性病原体中一些最容易理解的毒素（例如霍乱毒素）。本研究的初步数据表明，HopU1是一种活性ADP-RT，它能使几种植物蛋白发生adp核苷化。质谱分析表明，叶绿体和富含甘氨酸的rna结合蛋白是HopU1的体外底物。这些都是adp - rt的新型底物。此外，HopU1能够抑制植物先天免疫系统的几种反应，这种反应依赖于它的ADP-RT活性位点。缺乏HopU1底物AtGRP7的拟南芥突变体对丁香假单胞菌的易感性增强，这表明它是先天免疫的一个组成部分。AtGRP7是一种富含甘氨酸的RNA结合蛋白，这表明该病原体靶向参与RNA代谢的蛋白来抑制先天免疫。所提出的实验的中心假设是AtGRP7和HopU1 ADP-RT III型效应物的其他靶点可能是先天免疫的组成部分。一些实验试图利用生化和分子生物学方法阐明AtGRP7在先天免疫中的作用。由于资源丰富、真核生物天然免疫系统的相似性以及研究成本高，丁香拟南芥病理系统是研究天然免疫系统的一个很好的模型。这些实验将有助于对细菌发病和先天免疫的分子机制有一个基本的了解。

项目成果

Screen of Non-annotated Small Secreted Proteins of Pseudomonas syringae Reveals a Virulence Factor That Inhibits Tomato Immune Proteases.

• DOI: 10.1371/journal.ppat.1005874
• 发表时间: 2016-09
• 期刊: PLoS pathogens
• 影响因子: 6.7
• 作者: Shindo T;Kaschani F;Yang F;Kovács J;Tian F;Kourelis J;Hong TN;Colby T;Shabab M;Chawla R;Kumari S;Ilyas M;Hörger AC;Alfano JR;van der Hoorn RA
• 通讯作者: van der Hoorn RA

Roadmap for future research on plant pathogen effectors.

未来研究植物病原体效应子的路线图。

• DOI: 10.1111/j.1364-3703.2009.00588.x
• 发表时间: 2009-11
• 期刊: MOLECULAR PLANT PATHOLOGY
• 影响因子: 4.9
• 作者: Alfano, James R.

Plant targets for Pseudomonas syringae type III effectors: virulence targets or guarded decoys?

• DOI: 10.1016/j.mib.2010.12.011
• 发表时间: 2011-02
• 期刊: Current opinion in microbiology
• 影响因子: 5.4
• 作者: Block A;Alfano JR
• 通讯作者: Alfano JR

Effectors, effectors et encore des effectors: the XIV International Congress on Molecular-Plant Microbe Interactions, Quebec.

效应器、效应器和效应器的再演：第十四届国际分子-植物微生物相互作用大会，魁北克。

• DOI: 10.1094/mpmi-22-12-1479
• 发表时间: 2009
• 期刊: Molecular plant-microbe interactions : MPMI
• 作者: Walton,JonathanD;Avis,TylerJ;Alfano,JamesR;Gijzen,Mark;Spanu,Pietro;Hammond-Kosack,Kim;Sánchez,Federico
• 通讯作者: Sánchez,Federico

A putative RNA-binding protein positively regulates salicylic acid-mediated immunity in Arabidopsis.

• DOI: 10.1094/mpmi-05-10-0106
• 发表时间: 2010-11
• 期刊: Molecular plant-microbe interactions : MPMI
• 作者: Yiping Qi;K. Tsuda;Anna Joe;Masanao Sato;L. Nguyen;J. Glazebrook;J. Alfano;J. Cohen;F. Katagiri