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Schneider S, Wirth C, Jank T, Hunte C, Aktories K. Tyrosine-modifying glycosylation by Yersinia effectors. J Biol Chem 2024; 300:107331. [PMID: 38703997 PMCID: PMC11152714 DOI: 10.1016/j.jbc.2024.107331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 03/20/2024] [Accepted: 03/23/2024] [Indexed: 05/06/2024] Open
Abstract
Mono-O-glycosylation of target proteins by bacterial toxins or effector proteins is a well-known mechanism by which bacteria interfere with essential functions of host cells. The respective glycosyltransferases are important virulence factors such as the Clostridioides difficile toxins A and B. Here, we describe two glycosyltransferases of Yersinia species that have a high sequence identity: YeGT from the zoonotic pathogen Yersinia enterocolitica and YkGT from the murine pathogen Yersinia kristensenii. We show that both modify Rho family proteins by attachment of GlcNAc at tyrosine residues (Tyr-34 in RhoA). Notably, the enzymes differed in their target protein specificity. While YeGT modified RhoA, B, and C, YkGT possessed a broader substrate spectrum and glycosylated not only Rho but also Rac and Cdc42 subfamily proteins. Mutagenesis studies indicated that residue 177 is important for this broader target spectrum. We determined the crystal structure of YeGT shortened by 16 residues N terminally (sYeGT) in the ligand-free state and bound to UDP, the product of substrate hydrolysis. The structure assigns sYeGT to the GT-A family. It shares high structural similarity to glycosyltransferase domains from toxins. We also demonstrated that the 16 most N-terminal residues of YeGT and YkGT are important for the mediated translocation into the host cell using the pore-forming protective antigen of anthrax toxin. Mediated introduction into HeLa cells or ectopic expression of YeGT and YkGT caused morphological changes and redistribution of the actin cytoskeleton. The data suggest that YeGT and YkGT are likely bacterial effectors belonging to the family of tyrosine glycosylating bacterial glycosyltransferases.
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Affiliation(s)
- Silvia Schneider
- Faculty of Medicine, Institute for Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - Christophe Wirth
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, University of Freiburg, Freiburg, Germany.
| | - Thomas Jank
- Faculty of Medicine, Institute for Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - Carola Hunte
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, University of Freiburg, Freiburg, Germany; Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Klaus Aktories
- Faculty of Medicine, Institute for Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany; Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg, Germany.
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Zhou Y, Zhan X, Luo J, Li D, Zhou R, Zhang J, Pan Z, Zhang Y, Jia T, Zhang X, Li Y, Tao L. Structural dynamics of the CROPs domain control stability and toxicity of Paeniclostridium sordellii lethal toxin. Nat Commun 2023; 14:8426. [PMID: 38114525 PMCID: PMC10730571 DOI: 10.1038/s41467-023-44169-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 12/04/2023] [Indexed: 12/21/2023] Open
Abstract
Paeniclostridium sordellii lethal toxin (TcsL) is a potent exotoxin that causes lethal toxic shock syndrome associated with fulminant bacterial infections. TcsL belongs to the large clostridial toxin (LCT) family. Here, we report that TcsL with varied lengths of combined repetitive oligopeptides (CROPs) deleted show increased autoproteolysis as well as higher cytotoxicity. We next present cryo-EM structures of full-length TcsL, at neutral (pH 7.4) and acidic (pH 5.0) conditions. The TcsL at neutral pH exhibits in the open conformation, which resembles reported TcdB structures. Low pH induces the conformational change of partial TcsL to the closed form. Two intracellular interfaces are observed in the closed conformation, which possibly locks the cysteine protease domain and hinders the binding of the host receptor. Our findings provide insights into the structure and function of TcsL and reveal mechanisms for CROPs-mediated modulation of autoproteolysis and cytotoxicity, which could be common across the LCT family.
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Affiliation(s)
- Yao Zhou
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
- Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang, 310024, China
| | - Xiechao Zhan
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China.
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China.
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China.
| | - Jianhua Luo
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
- Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang, 310024, China
| | - Diyin Li
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
- Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang, 310024, China
| | - Ruoyu Zhou
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
| | - Jiahao Zhang
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
| | - Zhenrui Pan
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
| | - Yuanyuan Zhang
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
| | - Tianhui Jia
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
- Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang, 310024, China
| | - Xiaofeng Zhang
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
| | - Yanyan Li
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
| | - Liang Tao
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China.
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China.
- Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China.
- Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang, 310024, China.
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Zhang D, Wang Z, Yamamoto N, Wang M, Yi X, Li P, Lin R, Nasimi Z, Okada K, Mochida K, Noutoshi Y, Zheng A. Secreted Glycosyltransferase RsIA_GT of Rhizoctonia solani AG-1 IA Inhibits Defense Responses in Nicotiana benthamiana. Pathogens 2022; 11:pathogens11091026. [PMID: 36145458 PMCID: PMC9501517 DOI: 10.3390/pathogens11091026] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 08/31/2022] [Accepted: 09/03/2022] [Indexed: 11/16/2022] Open
Abstract
Anastomosis group AG-1 IA of Rhizoctonia solani Khün has a wide host range and threatens crop production. Various glycosyltransferases secreted by phytopathogenic fungi play an essential role in pathogenicity. Previously, we identified a glycosyltransferase RsIA_GT (AG11A_09161) as a secreted protein-encoding gene of R. solani AG-1 IA, whose expression levels increased during infection in rice. In this study, we further characterized the virulence function of RsIA_GT. It is conserved not only in Basidiomycota, including multiple anastomosis groups of R. solani, but also in other primary fungal taxonomic categories. RsIA_GT possesses a signal peptide (SP) for protein secretion, and its functionality was proven using yeast and Nicotiana benthamiana. The SP-truncated form of RsIA_GT (RsIA_GT(ΔS)) expressed in Escherichia coli-induced lesion-like phenotype in rice leaves when applied to punched leaves. However, Agrobacterium-mediated transient expressions of both the full-length RsIA_GT and RsIA_GT(ΔS) did not induce cell death in N. benthamiana leaves. Instead, only RsIA_GT(ΔS) suppressed the cell death induced by two reference cell death factors BAX and INF1 in N.benthamiana. RsIA_GT(ΔS)R154A D168A D170A, a mutant RsIA_GT(ΔS) for the glycosyltransferase catalytic domain, still suppressed the BAX- or INF1-induced cell death, suggesting that the cell death suppression activity of RsIA_GT(ΔS) would be independent from its enzymatic activity. RsIA_GT(ΔS) also suppressed the H2O2 production and callose deposition and showed an effect on the induction of defense genes associated with the expression of BAX and INF1. The transient expression of RsIA_GT(ΔS) in N. benthamiana enhanced the lesion area caused by R. solani AG-1 IA. The secreted glycosyltransferase, RsIA_GT, of R. solani AG-1 IA is likely to have a dual role in virulence inside and outside of host cells.
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Affiliation(s)
- Danhua Zhang
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Zhaoyilin Wang
- Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Naoki Yamamoto
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Mingyue Wang
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Xiaoqun Yi
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Ping Li
- Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Runmao Lin
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zohreh Nasimi
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Kazunori Okada
- Agro-Biotechnology Research Center, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Keiichi Mochida
- Bioproductivity Informatics Research Team, RIKEN Center for Sustainable Resource Science, Yokohama 2300045, Japan
- Microalgae Production Control Technology Laboratory, RIKEN Baton Zone Program, RIKEN Cluster for Science, Technology and Innovation Hub, Yokohama 2300045, Japan
- Kihara Institute for Biological Research, Yokohama City University, Yokohama 2440813, Japan
- School of Information and Data Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Yoshiteru Noutoshi
- Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan
| | - Aiping Zheng
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Chengdu 611130, China
- Correspondence:
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Abstract
Large clostridial toxins (LCTs) are a family of bacterial exotoxins that infiltrate and destroy target cells. Members of the LCT family include Clostridioides difficile toxins TcdA and TcdB, Paeniclostridium sordellii toxins TcsL and TcsH, Clostridium novyi toxin TcnA, and Clostridium perfringens toxin TpeL. Since the 19th century, LCT-secreting bacteria have been isolated from the blood, organs, and wounds of diseased individuals, and LCTs have been implicated as the primary virulence factors in a variety of infections, including C. difficile infection and some cases of wound-associated gas gangrene. Clostridia express and secrete LCTs in response to various physiological signals. LCTs invade host cells by binding specific cell surface receptors, ultimately leading to internalization into acidified vesicles. Acidic pH promotes conformational changes within LCTs, which culminates in translocation of the N-terminal glycosyltransferase and cysteine protease domain across the endosomal membrane and into the cytosol, leading first to cytopathic effects and later to cytotoxic effects. The focus of this review is on the role of LCTs in infection and disease, the mechanism of LCT intoxication, with emphasis on recent structural work and toxin subtyping analysis, and the genomic discovery and characterization of LCT homologues. We provide a comprehensive review of these topics and offer our perspective on emerging questions and future research directions for this enigmatic family of toxins.
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5
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Lemichez E, Popoff MR, Satchell KJF. Cellular microbiology: Bacterial toxin interference drives understanding of eukaryotic cell function. Cell Microbiol 2021; 22:e13178. [PMID: 32185903 DOI: 10.1111/cmi.13178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/04/2019] [Accepted: 11/08/2019] [Indexed: 11/28/2022]
Abstract
Intimate interactions between the armament of pathogens and their host dictate tissue and host susceptibility to infection also forging specific pathophysiological outcomes. Studying these interactions at the molecular level has provided an invaluable source of knowledge on cellular processes, as ambitioned by the Cellular Microbiology discipline when it emerged in early 90s. Bacterial toxins act on key cell regulators or membranes to produce major diseases and therefore constitute a remarkable toolbox for dissecting basic biological processes. Here, we review selected examples of recent studies on bacterial toxins illustrating how fruitful the discipline of cellular microbiology is in shaping our understanding of eukaryote processes. This ever-renewing discipline unveils new virulence factor biochemical activities shared by eukaryotic enzymes and hidden rules of cell proteome homeostasis, a particularly promising field to interrogate the impact of proteostasis breaching in late onset human diseases. It is integrating new concepts from the physics of soft matter to capture biomechanical determinants forging cells and tissues architecture. The success of this discipline is also grounded by the development of therapeutic tools and new strategies to treat both infectious and noncommunicable human diseases.
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Affiliation(s)
- Emmanuel Lemichez
- Unité des Toxines Bactériennes, CNRS ERL6002, Institut Pasteur, Paris, France
| | | | - Karla J F Satchell
- Department of Microbiology-Immunology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
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6
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Varela-Chavez C, Blondel A, Popoff MR. Bacterial intracellularly active toxins: Membrane localisation of the active domain. Cell Microbiol 2020; 22:e13213. [PMID: 32353188 DOI: 10.1111/cmi.13213] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/06/2020] [Accepted: 04/17/2020] [Indexed: 12/31/2022]
Abstract
Numerous bacterial toxins exert their activity by inactivating or modulating a specific intracellular host target. For this purpose, these toxins have developed efficient strategies to overcome the different host cell defences including specific binding to cell surface, internalisation, passage through the endosome or plasma membrane, exploiting intracellular trafficking and addressing to intracellular targets. Several intracellularly active toxins deliver an active domain into the cytosol that interacts with a target localised to the inner face of the plasma membrane. Thus, the large clostridial glucosylating toxins (LCGTs) target Rho/Ras-GTPases, certain virulence factors of Gram negative bacteria, Rho-GTPases, while Pasteurella multocida toxin (PMT) targets trimeric G-proteins. Others such as botulinum neurotoxins and tetanus neurotoxin have their substrate on synaptic vesicle membrane. LCGTs, PMT, and certain virulence factors from Vibrio sp. show a particular structure constituted of a four-helix bundle membrane (4HBM) protruding from the catalytic site that specifically binds to the membrane phospholipids and then trap the catalytic domain at the proximity of the membrane anchored substrate. Structural and functional analysis indicate that the 4HBM tip of the Clostridium sordellii lethal toxin (TcsL) from the LCGT family contain two loops forming a cavity that mediates the binding to phospholipids and more specifically to phosphatidylserine.
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Affiliation(s)
| | - Arnaud Blondel
- Unité de Bio-Informatique Structurale, Institut Pasteur, Paris, France
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Tian S, Liu Y, Wu H, Liu H, Zeng J, Choi MY, Chen H, Gerhard R, Dong M. Genome-Wide CRISPR Screen Identifies Semaphorin 6A and 6B as Receptors for Paeniclostridium sordellii Toxin TcsL. Cell Host Microbe 2020; 27:782-792.e7. [PMID: 32302524 DOI: 10.1016/j.chom.2020.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/04/2020] [Accepted: 03/11/2020] [Indexed: 01/21/2023]
Abstract
The exotoxin TcsL is a major virulence factor in Paeniclostridium (Clostridium) sordellii and responsible for the high lethality rate associated with P. sordellii infection. Here, we present a genome-wide CRISPR-Cas9-mediated screen using a human lung carcinoma cell line and identify semaphorin (SEMA) 6A and 6B as receptors for TcsL. Disrupting SEMA6A/6B expression in several distinct human cell lines and primary human endothelial cells results in reduced TcsL sensitivity, while SEMA6A/6B over-expression increases their sensitivity. TcsL recognizes the extracellular domain (ECD) of SEMA6A/6B via a region homologous to the receptor-binding site in Clostridioides difficile toxin B (TcdB), which binds the human receptor Frizzled. Exchanging the receptor-binding interfaces between TcsL and TcdB switches their receptor-binding specificity. Finally, administration of SEMA6A-ECD proteins protects human cells from TcsL toxicity and reduces TcsL-induced damage to lung tissues and the lethality rate in mice. These findings establish SEMA6A and 6B as pathophysiologically relevant receptors for TcsL.
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Affiliation(s)
- Songhai Tian
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Yang Liu
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Department of Nephrology, The First Hospital of Jilin University, Changchun 130012, China
| | - Hao Wu
- The Vascular Biology Program, Department of Surgery, Boston Children's Hospital and Harvard Medical School, MA 02115, USA
| | - Hao Liu
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ji Zeng
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Mei Yuk Choi
- Division of Genetics, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Hong Chen
- The Vascular Biology Program, Department of Surgery, Boston Children's Hospital and Harvard Medical School, MA 02115, USA
| | - Ralf Gerhard
- Institute of Toxicology, Hannover Medical School, Hannover, 30625, Germany
| | - Min Dong
- Department of Urology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Surgery and Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA.
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Wu Y, Pons V, Noël R, Kali S, Shtanko O, Davey RA, Popoff MR, Tordo N, Gillet D, Cintrat JC, Barbier J. DABMA: A Derivative of ABMA with Improved Broad-Spectrum Inhibitory Activity of Toxins and Viruses. ACS Med Chem Lett 2019; 10:1140-1147. [PMID: 31413797 DOI: 10.1021/acsmedchemlett.9b00155] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 07/02/2019] [Indexed: 02/08/2023] Open
Abstract
The small molecule ABMA has been previously shown to protect cells against multiple toxins and pathogens including virus, intracellular bacteria, and parasite. Its mechanism of action is directly associated with host endolysosomal pathway rather than targeting toxin or pathogen itself. However, the relationship of its broad-spectrum anti-infection activity and chemical structure is not yet resolved. Here, we synthesized a series of derivatives and compared their activities against diphtheria toxin (DT). Dimethyl-ABMA (DABMA), one of the most potent analogs with about 20-fold improvement in protection efficacy against DT, was identified with a similar mechanism of action to ABMA. Moreover, DABMA exhibited enhanced efficacy against Clostridium difficile toxin B (TcdB), Clostridium sordellii lethal toxin (TcsL), Pseudomonas Exotoxin A (PE) as well as Rabies and Ebola viruses. The results revealed a structure-activity relationship of ABMA, which is a starting point for its clinical development as broad-spectrum drug against existing and emerging infectious diseases.
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Affiliation(s)
- Yu Wu
- Service d’Ingénierie Moléculaire des Protéines (SIMOPRO), CEA, Université
Paris-Saclay, LabEx LERMIT, 91191 Gif-sur-Yvette, France
| | - Valérie Pons
- Service de Chimie Bio-organique et de Marquage (SCBM), CEA, Université Paris-Saclay, LabEx LERMIT, 91191 Gif-sur-Yvette, France
| | - Romain Noël
- Service de Chimie Bio-organique et de Marquage (SCBM), CEA, Université Paris-Saclay, LabEx LERMIT, 91191 Gif-sur-Yvette, France
| | - Sabrina Kali
- Antiviral Strategies Unit, Virology Department, Institut Pasteur, 75015 Paris, France
| | - Olena Shtanko
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas 78227, United States
| | - Robert A. Davey
- Department of Microbiology, NEIDL, Boston University, Boston, Massachusetts 02118, United States
| | - Michel R. Popoff
- Bactéries anaérobies et Toxines, Institut Pasteur, 75015 Paris, France
| | - Noël Tordo
- Antiviral Strategies Unit, Virology Department, Institut Pasteur, 75015 Paris, France
| | - Daniel Gillet
- Service d’Ingénierie Moléculaire des Protéines (SIMOPRO), CEA, Université
Paris-Saclay, LabEx LERMIT, 91191 Gif-sur-Yvette, France
| | - Jean-Christophe Cintrat
- Service de Chimie Bio-organique et de Marquage (SCBM), CEA, Université Paris-Saclay, LabEx LERMIT, 91191 Gif-sur-Yvette, France
| | - Julien Barbier
- Service d’Ingénierie Moléculaire des Protéines (SIMOPRO), CEA, Université
Paris-Saclay, LabEx LERMIT, 91191 Gif-sur-Yvette, France
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9
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Mileto S, Das A, Lyras D. Enterotoxic Clostridia: Clostridioides difficile Infections. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0015-2018. [PMID: 31124432 PMCID: PMC11026080 DOI: 10.1128/microbiolspec.gpp3-0015-2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Indexed: 12/17/2022] Open
Abstract
Clostridioides difficile is a Gram-positive, anaerobic, spore forming pathogen of both humans and animals and is the most common identifiable infectious agent of nosocomial antibiotic-associated diarrhea. Infection can occur following the ingestion and germination of spores, often concurrently with a disruption to the gastrointestinal microbiota, with the resulting disease presenting as a spectrum, ranging from mild and self-limiting diarrhea to severe diarrhea that may progress to life-threating syndromes that include toxic megacolon and pseudomembranous colitis. Disease is induced through the activity of the C. difficile toxins TcdA and TcdB, both of which disrupt the Rho family of GTPases in host cells, causing cell rounding and death and leading to fluid loss and diarrhea. These toxins, despite their functional and structural similarity, do not contribute to disease equally. C. difficile infection (CDI) is made more complex by a high level of strain diversity and the emergence of epidemic strains, including ribotype 027-strains which induce more severe disease in patients. With the changing epidemiology of CDI, our understanding of C. difficile disease, diagnosis, and pathogenesis continues to evolve. This article provides an overview of the current diagnostic tests available for CDI, strain typing, the major toxins C. difficile produces and their mode of action, the host immune response to each toxin and during infection, animal models of disease, and the current treatment and prevention strategies for CDI.
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Affiliation(s)
- S Mileto
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia, 3800
| | - A Das
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia, 3800
| | - D Lyras
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia, 3800
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10
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Popoff MR. Clostridium difficile and Clostridium sordellii toxins, proinflammatory versus anti-inflammatory response. Toxicon 2018; 149:54-64. [DOI: 10.1016/j.toxicon.2017.11.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 11/07/2017] [Accepted: 11/09/2017] [Indexed: 12/17/2022]
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11
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Junemann J, Lämmerhirt CM, Polten F, Just I, Gerhard R, Genth H, Pich A. Quantification of small GTPase glucosylation by clostridial glucosylating toxins using multiplexed MRM analysis. Proteomics 2017; 17. [PMID: 28252257 DOI: 10.1002/pmic.201700016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/10/2017] [Accepted: 02/28/2017] [Indexed: 12/29/2022]
Abstract
Large clostridial toxins mono-O-glucosylate small GTPases of the Rho and Ras subfamily. As a result of glucosylation, the GTPases are inhibited and thereby corresponding downstream signaling pathways are disturbed. Current methods for quantifying the extent of glucosylation include sequential [14 C]glucosylation, sequential [32 P]ADP-ribosylation, and Western Blot detection of nonglucosylated GTPases, with neither method allowing the quantification of the extent of glucosylation of an individual GTPase. Here, we describe a novel MS-based multiplexed MRM assay to specifically quantify the glucosylation degree of small GTPases. This targeted proteomics approach achieves a high selectivity and reproducibility, which allows determination of the in vivo substrate pattern of glucosylating toxins. As proof of principle, GTPase glucosylation was analyzed in CaCo-2 cells treated with TcdA, and glucosylation kinetics were determined for RhoA/B, RhoC, RhoG, Ral, Rap1, Rap2, (H/K/N)Ras, and R-Ras2.
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Affiliation(s)
- Johannes Junemann
- Hannover Medical School, Institute for Toxicology, Hannover, Germany
| | | | - Felix Polten
- Hannover Medical School, Institute for Toxicology, Hannover, Germany
| | - Ingo Just
- Hannover Medical School, Institute for Toxicology, Hannover, Germany
| | - Ralf Gerhard
- Hannover Medical School, Institute for Toxicology, Hannover, Germany
| | - Harald Genth
- Hannover Medical School, Institute for Toxicology, Hannover, Germany
| | - Andreas Pich
- Hannover Medical School, Institute for Toxicology, Hannover, Germany
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12
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ABMA, a small molecule that inhibits intracellular toxins and pathogens by interfering with late endosomal compartments. Sci Rep 2017; 7:15567. [PMID: 29138439 PMCID: PMC5686106 DOI: 10.1038/s41598-017-15466-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/24/2017] [Indexed: 12/30/2022] Open
Abstract
Intracellular pathogenic microorganisms and toxins exploit host cell mechanisms to enter, exert their deleterious effects as well as hijack host nutrition for their development. A potential approach to treat multiple pathogen infections and that should not induce drug resistance is the use of small molecules that target host components. We identified the compound 1-adamantyl (5-bromo-2-methoxybenzyl) amine (ABMA) from a cell-based high throughput screening for its capacity to protect human cells and mice against ricin toxin without toxicity. This compound efficiently protects cells against various toxins and pathogens including viruses, intracellular bacteria and parasite. ABMA provokes Rab7-positive late endosomal compartment accumulation in mammalian cells without affecting other organelles (early endosomes, lysosomes, the Golgi apparatus, the endoplasmic reticulum or the nucleus). As the mechanism of action of ABMA is restricted to host-endosomal compartments, it reduces cell infection by pathogens that depend on this pathway to invade cells. ABMA may represent a novel class of broad-spectrum compounds with therapeutic potential against diverse severe infectious diseases.
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13
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Chandrasekaran R, Lacy DB. The role of toxins in Clostridium difficile infection. FEMS Microbiol Rev 2017; 41:723-750. [PMID: 29048477 PMCID: PMC5812492 DOI: 10.1093/femsre/fux048] [Citation(s) in RCA: 210] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/10/2017] [Indexed: 02/06/2023] Open
Abstract
Clostridium difficile is a bacterial pathogen that is the leading cause of nosocomial antibiotic-associated diarrhea and pseudomembranous colitis worldwide. The incidence, severity, mortality and healthcare costs associated with C. difficile infection (CDI) are rising, making C. difficile a major threat to public health. Traditional treatments for CDI involve use of antibiotics such as metronidazole and vancomycin, but disease recurrence occurs in about 30% of patients, highlighting the need for new therapies. The pathogenesis of C. difficile is primarily mediated by the actions of two large clostridial glucosylating toxins, toxin A (TcdA) and toxin B (TcdB). Some strains produce a third toxin, the binary toxin C. difficile transferase, which can also contribute to C. difficile virulence and disease. These toxins act on the colonic epithelium and immune cells and induce a complex cascade of cellular events that result in fluid secretion, inflammation and tissue damage, which are the hallmark features of the disease. In this review, we summarize our current understanding of the structure and mechanism of action of the C. difficile toxins and their role in disease.
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Affiliation(s)
- Ramyavardhanee Chandrasekaran
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - D. Borden Lacy
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- The Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37232, USA
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14
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Biancucci M, Rabideau AE, Lu Z, Loftis AR, Pentelute BL, Satchell KJF. Substrate Recognition of MARTX Ras/Rap1-Specific Endopeptidase. Biochemistry 2017; 56:2747-2757. [PMID: 28459538 DOI: 10.1021/acs.biochem.7b00246] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ras/Rap1-specific endopeptidase (RRSP) is a cytotoxic effector domain of the multifunctional autoprocessing repeats-in-toxin (MARTX) toxin of highly virulent strains of Vibrio vulnificus. RRSP blocks RAS-MAPK kinase signaling by cleaving Ras and Rap1 within the switch I region between Y32 and D33. Although the RRSP processing site is highly conserved among small GTPases, only Ras and Rap1 have been identified as proteolytic substrates. Here we report that residues Y32 and D33 at the scissile bond play an important role in RRSP substrate recognition, while the nucleotide state of Ras has an only minimal effect. In addition, substrate specificity is generated by residues across the entire switch I region. Indeed, swapping the Ras switch I region into either RalA or RhoA, GTPases that are not recognized by RRSP, generated chimeras that are substrates of RRSP. However, a difference in the processing efficiency of Ras switch I in the context of Ras, RalA, or RhoA indicates that protein regions outside Ras switch I also contribute to efficient RRSP substrate recognition. Moreover, we show that synthetic peptides corresponding to the Ras and Rap1, but not RalA, switch I regions are cleaved by RRSP, demonstrating sequence-specific substrate recognition. In conclusion, this work demonstrates that the GTPase recognition of RRSP is independent of the nucleotide state and is mainly driven by the Ras and Rap1 switch I loop and also influenced by additional protein-protein interactions, increasing the substrate specificity of RRSP.
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Affiliation(s)
- Marco Biancucci
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine , Chicago, Illinois 60611, United States
| | - Amy E Rabideau
- Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Zeyu Lu
- Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Alex R Loftis
- Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Bradley L Pentelute
- Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Karla J F Satchell
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine , Chicago, Illinois 60611, United States
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15
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Chen S, Sun C, Gu H, Wang H, Li S, Ma Y, Wang J. Salubrinal protects against Clostridium difficile toxin B-induced CT26 cell death. Acta Biochim Biophys Sin (Shanghai) 2017; 49:228-237. [PMID: 28119311 DOI: 10.1093/abbs/gmw139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile (C. difficile) is considered to be the major cause of the antibiotic-associated diarrhea and pseudomembranous colitis in animals and humans. The prevalence of C. difficile infections (CDI) has been increasing since 2000. Two exotoxins of C. difficile, Toxin A (TcdA) and Toxin B (TcdB), are the main virulence factors of CDI, which can induce glucosylation of Rho GTPases in host cytosol, leading to cell morphological changes, cell apoptosis, and cell death. The mechanism of TcdB-induced cell death has been investigated for decades, but it is still not completely understood. It has been reported that TcdB induces endoplasmic reticulum stress via PERK-eIF2α signaling pathway in CT26 cell line (BALB/C mouse colon tumor cells). In this study, we found that salubrinal, a selective inhibitor of eIF2α dephosphorylation, efficiently protects CT26 cell line against TcdB-induced cell death and tried to explore the mechanism underlying in this protective effect. Our results demonstrated that salubrinal protects CT26 cells from TcdB-mediated cytotoxic and cytopathic effect, inhibits apoptosis and death of the toxin-exposed cells via caspase-9-dependent pathway, eIF2α signaling pathway, and autophagy. These findings will be helpful for the development of CDI therapies.
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Affiliation(s)
- Shuyi Chen
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Chunli Sun
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Huawei Gu
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Haiying Wang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Shan Li
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Yi Ma
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Jufang Wang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
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16
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Rho-modifying bacterial protein toxins from Photorhabdus species. Toxicon 2016; 116:17-22. [DOI: 10.1016/j.toxicon.2015.05.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/15/2015] [Accepted: 05/26/2015] [Indexed: 02/04/2023]
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17
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Varela Chavez C, Haustant GM, Baron B, England P, Chenal A, Pauillac S, Blondel A, Popoff MR. The Tip of the Four N-Terminal α-Helices of Clostridium sordellii Lethal Toxin Contains the Interaction Site with Membrane Phosphatidylserine Facilitating Small GTPases Glucosylation. Toxins (Basel) 2016; 8:90. [PMID: 27023605 PMCID: PMC4848617 DOI: 10.3390/toxins8040090] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/01/2016] [Accepted: 03/10/2016] [Indexed: 12/22/2022] Open
Abstract
Clostridium sordellii lethal toxin (TcsL) is a powerful virulence factor responsible for severe toxic shock in man and animals. TcsL belongs to the large clostridial glucosylating toxin (LCGT) family which inactivates small GTPases by glucosylation with uridine-diphosphate (UDP)-glucose as a cofactor. Notably, TcsL modifies Rac and Ras GTPases, leading to drastic alteration of the actin cytoskeleton and cell viability. TcsL enters cells via receptor-mediated endocytosis and delivers the N-terminal glucosylating domain (TcsL-cat) into the cytosol. TcsL-cat was found to preferentially bind to phosphatidylserine (PS)-containing membranes and to increase the glucosylation of Rac anchored to the lipid membrane. We have previously reported that the N-terminal four helical bundle structure (1–93 domain) recognizes a broad range of lipids, but that TcsL-cat specifically binds to PS and phosphatidic acid. Here, we show using mutagenesis that the PS binding site is localized on the tip of the four-helix bundle which is rich in positively-charged amino acids. Residues Y14, V15, F17, and R18 on loop 1, between helices 1 and 2, in coordination with R68 from loop 3, between helices 3 and 4, form a pocket which accommodates L-serine. The functional PS-binding site is required for TcsL-cat binding to the plasma membrane and subsequent cytotoxicity. TcsL-cat binding to PS facilitates a high enzymatic activity towards membrane-anchored Ras by about three orders of magnitude as compared to Ras in solution. The PS-binding site is conserved in LCGTs, which likely retain a common mechanism of binding to the membrane for their full activity towards membrane-bound GTPases.
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Affiliation(s)
- Carolina Varela Chavez
- Unité des Bactéries anaérobies et Toxines, Institut Pasteur, 75724 Paris cedex15, France.
| | | | - Bruno Baron
- Plate-Forme de Biophysique Moléculaires, Institut Pasteur, 75724 Paris cedex15, France.
| | - Patrick England
- Plate-Forme de Biophysique Moléculaires, Institut Pasteur, 75724 Paris cedex15, France.
| | - Alexandre Chenal
- Unité de Biochimie des Interactions Macromoléculaires, Institut Pasteur, 75724 Paris cedex15, France.
| | - Serge Pauillac
- Unité des Bactéries anaérobies et Toxines, Institut Pasteur, 75724 Paris cedex15, France.
| | - Arnaud Blondel
- Unité de Bioinformatique Structurale, Institut Pasteur, 75724 Paris cedex15, France.
| | - Michel-Robert Popoff
- Unité des Bactéries anaérobies et Toxines, Institut Pasteur, 75724 Paris cedex15, France.
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18
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Chen S, Sun C, Wang H, Wang J. The Role of Rho GTPases in Toxicity of Clostridium difficile Toxins. Toxins (Basel) 2015; 7:5254-67. [PMID: 26633511 PMCID: PMC4690124 DOI: 10.3390/toxins7124874] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/18/2015] [Accepted: 11/18/2015] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile (C. difficile) is the main cause of antibiotic-associated diarrhea prevailing in hospital settings. In the past decade, the morbidity and mortality of C. difficile infection (CDI) has increased significantly due to the emergence of hypervirulent strains. Toxin A (TcdA) and toxin B (TcdB), the two exotoxins of C. difficile, are the major virulence factors of CDI. The common mode of action of TcdA and TcdB is elicited by specific glucosylation of Rho-GTPase proteins in the host cytosol using UDP-glucose as a co-substrate, resulting in the inactivation of Rho proteins. Rho proteins are the key members in many biological processes and signaling pathways, inactivation of which leads to cytopathic and cytotoxic effects and immune responses of the host cells. It is supposed that Rho GTPases play an important role in the toxicity of C. difficile toxins. This review focuses on recent progresses in the understanding of functional consequences of Rho GTPases glucosylation induced by C. difficile toxins and the role of Rho GTPases in the toxicity of TcdA and TcdB.
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Affiliation(s)
- Shuyi Chen
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
| | - Chunli Sun
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
| | - Haiying Wang
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
| | - Jufang Wang
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
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19
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Clostridium sordellii Lethal-Toxin Autoprocessing and Membrane Localization Activities Drive GTPase Glucosylation Profiles in Endothelial Cells. mSphere 2015; 1:mSphere00012-15. [PMID: 27303685 PMCID: PMC4863631 DOI: 10.1128/msphere.00012-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/05/2015] [Indexed: 11/20/2022] Open
Abstract
Clostridium sordellii is a bacterium that can infect humans and cause serious disease and death. The principle virulence factor associated with clinical symptoms is a large protein toxin known as lethal toxin. The mechanism of lethal-toxin intoxication is assumed to be similar to that of the homologous toxins from C. difficile, but very few studies have been done in the context of endothelial cells, a relevant target in C. sordellii infections. This study was designed to test the role of the lethal-toxin enzymatic activities and membrane localization in endothelial cell toxicity and host substrate modification. Clostridium sordellii infections cause gangrene and edema in humans and gastrointestinal infections in livestock. One of the principle virulence factors is TcsL, a large protein toxin which glucosylates host GTPases to cause cytopathic and cytotoxic effects. TcsL has two enzymatic domains, an N-terminal glucosyltransferase domain (GTD) and an autoprocessing domain responsible for release of the GTD within the cell. The GTD can then use its N-terminal membrane localization domain (MLD) for orientation on membranes and modification of GTPases. This study describes the use of conditionally immortalized murine pulmonary microvascular endothelial cells as a model for the study of TcsL functional activities. Point mutations that disrupt the glucosyltransferase, autoprocessing, or membrane localization activities were introduced into a recombinant version of TcsL, and the activities of these mutants were compared to those of wild-type toxin. We observed that all mutants are defective or impaired in cytotoxicity but differ in their modification of Rac1 and Ras. The data suggest a model where differences in GTPase localization dictate cellular responses to intoxication and highlight the importance of autoprocessing in the function of TcsL. IMPORTANCEClostridium sordellii is a bacterium that can infect humans and cause serious disease and death. The principle virulence factor associated with clinical symptoms is a large protein toxin known as lethal toxin. The mechanism of lethal-toxin intoxication is assumed to be similar to that of the homologous toxins from C. difficile, but very few studies have been done in the context of endothelial cells, a relevant target in C. sordellii infections. This study was designed to test the role of the lethal-toxin enzymatic activities and membrane localization in endothelial cell toxicity and host substrate modification.
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20
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Tsuge H, Yoshida T, Tsurumura T. Conformational plasticity is crucial for C3-RhoA complex formation by ARTT-loop. Pathog Dis 2015; 73:ftv094. [PMID: 26474844 DOI: 10.1093/femspd/ftv094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2015] [Indexed: 01/22/2023] Open
Abstract
ADP-ribosylation is an important post-translational protein modification catalyzed by bacterial toxins and eukaryotic endogenous ADP-ribosyltransferases. Bacterial binary toxins and C3-like toxins recognize and ADP-ribosylate actin Arg177 and RhoA Asn41, respectively. Structural and mutational studies have identified an ADP-ribosylating turn-turn loop (ARTT-loop) that has been implicated in substrate specificity and recognition, although it has not been verified. Recently, we determined the crystal structure of the C3 exoenzyme-RhoA complex. The complex structure shows how C3 recognizes Rho GTPase and provides the first structural evidence for RhoA recognition by the ARTT-loop. The complex formation mediated by the ARTT-loop is through the intrinsic plasticity of C3 and RhoA. C3 changes the conformations of both the phosphate nicotinamide-loop and the ARTT-loop by NAD(+) and RhoA binding, respectively. In contrast, RhoA changes the conformations of switch I and II regions upon C3 binding with a particular conformation, irrespective of the bound nucleotide (GTP or GDP).
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Affiliation(s)
- Hideaki Tsuge
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences and Structural Biology Research Center, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
| | - Toru Yoshida
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences and Structural Biology Research Center, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
| | - Toshiharu Tsurumura
- Department of Bioresource and Environmental Sciences, Faculty of Life Sciences and Structural Biology Research Center, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
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21
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Antic I, Biancucci M, Zhu Y, Gius DR, Satchell KJF. Site-specific processing of Ras and Rap1 Switch I by a MARTX toxin effector domain. Nat Commun 2015; 6:7396. [PMID: 26051945 PMCID: PMC4468845 DOI: 10.1038/ncomms8396] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 05/01/2015] [Indexed: 12/31/2022] Open
Abstract
Ras (Rat sarcoma) protein is a central regulator of cell growth and proliferation. Mutations in the RAS gene are known to occur in human cancers and have been shown to contribute to carcinogenesis. In this study, we show that the multifunctional-autoprocessing repeats-in-toxin (MARTX) toxin-effector domain DUF5Vv from Vibrio vulnificus to be a site-specific endopeptidase that cleaves within the Switch 1 region of Ras and Rap1. DUF5Vv processing of Ras, which occurs both biochemically and in mammalian cell culture, inactivates ERK1/2, thereby inhibiting cell proliferation. The ability to cleave Ras and Rap1 is shared by DUF5Vv homologues found in other bacteria. In addition, DUF5Vv can cleave all Ras isoforms and KRas with mutations commonly implicated in malignancies. Therefore, we speculate that this new family of Ras/Rap1-specific endopeptidases (RRSPs) has potential to inactivate both wild-type and mutant Ras proteins expressed in malignancies. V. vulnificus, a bacteria that cause life-threatening septicaemia following wound infections or tainted food consumption, utilizes MARTX toxins for toxic effector delivery. Here the authors show that the MARTX virulence factor DUF5 targets the cellular MAP kinase pathway as a Ras and Rap1 site-specific protease.
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Affiliation(s)
- Irena Antic
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Ward 6-225, Chicago, Illinois 60611, USA
| | - Marco Biancucci
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Ward 6-225, Chicago, Illinois 60611, USA
| | - Yueming Zhu
- Department of Radiation Oncology and Pharmacology, Feinberg School of Medicine, Northwestern University, 303 East Superior Avenue, Lurie 3-119, Chicago, Illinois 60611, USA
| | - David R Gius
- Department of Radiation Oncology and Pharmacology, Feinberg School of Medicine, Northwestern University, 303 East Superior Avenue, Lurie 3-119, Chicago, Illinois 60611, USA
| | - Karla J F Satchell
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Ward 6-225, Chicago, Illinois 60611, USA
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22
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Varela Chavez C, Hoos S, Haustant GM, Chenal A, England P, Blondel A, Pauillac S, Lacy DB, Popoff MR. The catalytic domains of Clostridium sordellii lethal toxin and related large clostridial glucosylating toxins specifically recognize the negatively charged phospholipids phosphatidylserine and phosphatidic acid. Cell Microbiol 2015; 17:1477-93. [PMID: 25882477 DOI: 10.1111/cmi.12449] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/15/2015] [Indexed: 12/23/2022]
Abstract
Clostridium sordellii lethal toxin (TcsL) is a potent virulence factor belonging to the large clostridial glucosylating toxin family. TcsL enters target cells via receptor-mediated endocytosis and delivers the N-terminal catalytic domain (TcsL-cat) into the cytosol upon an autoproteolytic process. TcsL-cat inactivates small GTPases including Rac and Ras by glucosylation with uridine-diphosphate (UDP)-glucose as cofactor leading to drastic changes in cytoskeleton and cell viability. TcsL-cat was found to preferentially bind to phosphatidylserine (PS)-containing membranes and to increase the glucosylation of Rac anchored to lipid membrane. We here report binding affinity measurements of TcsL-cat for brain PS-containing membranes by surface plasmon resonance and enzyme-linked immunosorbent assay (ELISA). In addition, TcsL-cat bound to phosphatidic acid (PA) and, to a lesser extent, to other anionic lipids, but not to neutral lipids, sphingolipids or sterol. We further show that the lipid unsaturation status influenced TcsL-cat binding to phospholipids, PS with unsaturated acyl chains and PA with saturated acyl chains being the preferred bindingsubstrates. Phospholipid binding site is localized at the N-terminal four helical bundle structure (1-93 domain). However, TcsL-1-93 bound to a broad range of substrates, whereas TcsL-cat, which is the active domain physiologically delivered into the cytosol, selectively bound to PS and PA. Similar findings were observed with the other large clostridial glucosylating toxins from C. difficile, C. novyi and C. perfringens.
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Affiliation(s)
| | - Sylviane Hoos
- Plateforme de Biophysique Moléculaire, Institut Pasteur, Paris, France
| | | | - Alexandre Chenal
- Unité de Biochimie des Interactions Macromoléculaires, Institut Pasteur, Paris, France
| | - Patrick England
- Plateforme de Biophysique Moléculaire, Institut Pasteur, Paris, France
| | - Arnaud Blondel
- Unité de Bioinformatique Structurale, Institut Pasteur, Paris, France
| | - Serge Pauillac
- Unité des Bactéries anaérobies et Toxines, Institut Pasteur, Paris, France
| | - D Borden Lacy
- Unité de Bioinformatique Structurale, Institut Pasteur, Paris, France.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
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23
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Jank T, Trillhaase C, Brozda N, Steinemann M, Schwan C, Süss R, Aktories K. Intracellular plasma membrane guidance of
Photorhabdus asymbiotica
toxin is crucial for cell toxicity. FASEB J 2015; 29:2789-802. [DOI: 10.1096/fj.14-269381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 02/26/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Thomas Jank
- Departments of Experimental and Clinical Pharmacology and ToxicologyUniversity of FreiburgFreiburgGermany
| | - Christoph Trillhaase
- Departments of Experimental and Clinical Pharmacology and ToxicologyUniversity of FreiburgFreiburgGermany
| | - Natalia Brozda
- Departments of Experimental and Clinical Pharmacology and ToxicologyUniversity of FreiburgFreiburgGermany
| | - Marcus Steinemann
- Departments of Experimental and Clinical Pharmacology and ToxicologyUniversity of FreiburgFreiburgGermany
| | - Carsten Schwan
- Departments of Experimental and Clinical Pharmacology and ToxicologyUniversity of FreiburgFreiburgGermany
| | - Regine Süss
- Pharmaceutical Technology and BiopharmacyUniversity of FreiburgFreiburgGermany
| | - Klaus Aktories
- Departments of Experimental and Clinical Pharmacology and ToxicologyUniversity of FreiburgFreiburgGermany
- Centre for Biological Signalling Studies, University of FreiburgFreiburgGermany
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24
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D'Auria KM, Bloom MJ, Reyes Y, Gray MC, van Opstal EJ, Papin JA, Hewlett EL. High temporal resolution of glucosyltransferase dependent and independent effects of Clostridium difficile toxins across multiple cell types. BMC Microbiol 2015; 15:7. [PMID: 25648517 PMCID: PMC4323251 DOI: 10.1186/s12866-015-0361-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 01/22/2015] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Clostridium difficile toxins A and B (TcdA and TcdB), considered to be essential for C. difficile infection, affect the morphology of several cell types with different potencies and timing. However, morphological changes over various time scales are poorly characterized. The toxins' glucosyltransferase domains are critical to their deleterious effects, and cell responses to glucosyltransferase-independent activities are incompletely understood. By tracking morphological changes of multiple cell types to C. difficile toxins with high temporal resolution, cellular responses to TcdA, TcdB, and a glucosyltransferase-deficient TcdB (gdTcdB) are elucidated. RESULTS Human umbilical vein endothelial cells, J774 macrophage-like cells, and four epithelial cell lines (HCT8, T84, CHO, and immortalized mouse cecal epithelial cells) were treated with TcdA, TcdB, gdTcdB. Impedance across cell cultures was measured to track changes in cell morphology. Metrics from impedance data, developed to quantify rapid and long-lasting responses, produced standard curves with wide dynamic ranges that defined cell line sensitivities. Except for T84 cells, all cell lines were most sensitive to TcdB. J774 macrophages stretched and increased in size in response to TcdA and TcdB but not gdTcdB. High concentrations of TcdB and gdTcdB (>10 ng/ml) greatly reduced macrophage viability. In HCT8 cells, gdTcdB did not induce a rapid cytopathic effect, yet it delayed TcdA and TcdB's rapid effects. gdTcdB did not clearly delay TcdA or TcdB's toxin-induced effects on macrophages. CONCLUSIONS Epithelial and endothelial cells have similar responses to toxins yet differ in timing and degree. Relative potencies of TcdA and TcdB in mouse epithelial cells in vitro do not correlate with potencies in vivo. TcdB requires glucosyltransferase activity to cause macrophages to spread, but cell death from high TcdB concentrations is glucosyltransferase-independent. Competition experiments with gdTcdB in epithelial cells confirm common TcdA and TcdB mechanisms, yet different responses of macrophages to TcdA and TcdB suggest different, additional mechanisms or targets in these cells. This first-time, precise quantification of the response of multiple cell lines to TcdA and TcdB provides a comparative framework for delineating the roles of different cell types and toxin-host interactions.
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Affiliation(s)
- Kevin M D'Auria
- Department of Biomedical Engineering, University of Virginia, PO Box 800759, Charlottesville, VA, 22908, USA.
| | - Meghan J Bloom
- Department of Biomedical Engineering, University of Virginia, PO Box 800759, Charlottesville, VA, 22908, USA. .,Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, PO Box 801340, Charlottesville, VA, 22908, USA.
| | - Yesenia Reyes
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, PO Box 801340, Charlottesville, VA, 22908, USA.
| | - Mary C Gray
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, PO Box 801340, Charlottesville, VA, 22908, USA.
| | - Edward J van Opstal
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, PO Box 801340, Charlottesville, VA, 22908, USA. .,Current address: Vanderbilt University School of Medicine, 340 Light Hall, Nashville, TN, 27232, USA.
| | - Jason A Papin
- Department of Biomedical Engineering, University of Virginia, PO Box 800759, Charlottesville, VA, 22908, USA.
| | - Erik L Hewlett
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, PO Box 801340, Charlottesville, VA, 22908, USA.
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Woolery AR, Yu X, LaBaer J, Orth K. AMPylation of Rho GTPases subverts multiple host signaling processes. J Biol Chem 2014; 289:32977-88. [PMID: 25301945 DOI: 10.1074/jbc.m114.601310] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rho GTPases are frequent targets of virulence factors as they are keystone signaling molecules. Herein, we demonstrate that AMPylation of Rho GTPases by VopS is a multifaceted virulence mechanism that counters several host immunity strategies. Activation of NFκB, Erk, and JNK kinase signaling pathways were inhibited in a VopS-dependent manner during infection with Vibrio parahaemolyticus. Phosphorylation and degradation of IKBα were inhibited in the presence of VopS as was nuclear translocation of the NFκB subunit p65. AMPylation also prevented the generation of superoxide by the phagocytic NADPH oxidase complex, potentially by inhibiting the interaction of Rac and p67. Furthermore, the interaction of GTPases with the E3 ubiquitin ligases cIAP1 and XIAP was hindered, leading to decreased degradation of Rac and RhoA during infection. Finally, we screened for novel Rac1 interactions using a nucleic acid programmable protein array and discovered that Rac1 binds to the protein C1QA, a protein known to promote immune signaling in the cytosol. Interestingly, this interaction was disrupted by AMPylation. We conclude that AMPylation of Rho Family GTPases by VopS results in diverse inhibitory consequences during infection beyond the most obvious phenotype, the collapse of the actin cytoskeleton.
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Affiliation(s)
- Andrew R Woolery
- From the Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas 75390-9148 and
| | - Xiaobo Yu
- The Virginia G. Piper Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287
| | - Joshua LaBaer
- The Virginia G. Piper Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287
| | - Kim Orth
- From the Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas 75390-9148 and
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Genth H, Pauillac S, Schelle I, Bouvet P, Bouchier C, Varela-Chavez C, Just I, Popoff MR. Haemorrhagic toxin and lethal toxin from Clostridium sordellii strain vpi9048: molecular characterization and comparative analysis of substrate specificity of the large clostridial glucosylating toxins. Cell Microbiol 2014; 16:1706-21. [PMID: 24905543 DOI: 10.1111/cmi.12321] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 05/12/2014] [Accepted: 05/29/2014] [Indexed: 12/16/2022]
Abstract
Large clostridial glucosylating toxins (LCGTs) are produced by toxigenic strains of Clostridium difficile, Clostridium perfringens, Clostridium novyi and Clostridium sordellii. While most C. sordellii strains solely produce lethal toxin (TcsL), C. sordellii strain VPI9048 co-produces both hemorrhagic toxin (TcsH) and TcsL. Here, the sequences of TcsH-9048 and TcsL-9048 are provided, showing that both toxins retain conserved LCGT features and that TcsL and TcsH are highly related to Toxin A (TcdA) and Toxin B (TcdB) from C. difficile strain VPI10463. The substrate profile of the toxins was investigated with recombinant LCGT transferase domains (rN) and a wide panel of small GTPases. rN-TcsH-9048 and rN-TcdA-10463 glucosylated preferably Rho-GTPases but also Ras-GTPases to some extent. In this respect, rN-TcsH-9048 and rN-TcdA-10463 differ from the respective full-length TcsH-9048 and TcdA-10463, which exclusively glucosylate Rho-GTPases. rN-TcsL-9048 and full length TcsL-9048 glucosylate both Rho- and Ras-GTPases, whereas rN-TcdB-10463 and full length TcdB-10463 exclusively glucosylate Rho-GTPases. Vero cells treated with full length TcsH-9048 or TcdA-10463 also showed glucosylation of Ras, albeit to a lower extent than of Rho-GTPases. Thus, in vitro analysis of substrate spectra using recombinant transferase domains corresponding to the auto-proteolytically cleaved domains, predicts more precisely the in vivo substrates than the full length toxins. Except for TcdB-1470, all LCGTs evoked increased expression of the small GTPase RhoB, which exhibited cytoprotective activity in cells treated with TcsL isoforms, but pro-apoptotic activity in cells treated with TcdA, TcdB, and TcsH. All LCGTs induced a rapid dephosphorylation of pY118-paxillin and of pS144/141-PAK1/2 prior to actin filament depolymerization indicating that disassembly of focal adhesions is an early event leading to the disorganization of the actin cytoskeleton.
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Affiliation(s)
- Harald Genth
- Institute of Toxicology, Medical School Hannover, Hannover, Germany
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27
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Innate immune sensing of bacterial modifications of Rho GTPases by the Pyrin inflammasome. Nature 2014; 513:237-41. [PMID: 24919149 DOI: 10.1038/nature13449] [Citation(s) in RCA: 584] [Impact Index Per Article: 58.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Accepted: 05/07/2014] [Indexed: 01/13/2023]
Abstract
Cytosolic inflammasome complexes mediated by a pattern recognition receptor (PRR) defend against pathogen infection by activating caspase 1. Pyrin, a candidate PRR, can bind to the inflammasome adaptor ASC to form a caspase 1-activating complex. Mutations in the Pyrin-encoding gene, MEFV, cause a human autoinflammatory disease known as familial Mediterranean fever. Despite important roles in immunity and disease, the physiological function of Pyrin remains unknown. Here we show that Pyrin mediates caspase 1 inflammasome activation in response to Rho-glucosylation activity of cytotoxin TcdB, a major virulence factor of Clostridium difficile, which causes most cases of nosocomial diarrhoea. The glucosyltransferase-inactive TcdB mutant loses the inflammasome-stimulating activity. Other Rho-inactivating toxins, including FIC-domain adenylyltransferases (Vibrio parahaemolyticus VopS and Histophilus somni IbpA) and Clostridium botulinum ADP-ribosylating C3 toxin, can also biochemically activate the Pyrin inflammasome in their enzymatic activity-dependent manner. These toxins all target the Rho subfamily and modify a switch-I residue. We further demonstrate that Burkholderia cenocepacia inactivates RHOA by deamidating Asn 41, also in the switch-I region, and thereby triggers Pyrin inflammasome activation, both of which require the bacterial type VI secretion system (T6SS). Loss of the Pyrin inflammasome causes elevated intra-macrophage growth of B. cenocepacia and diminished lung inflammation in mice. Thus, Pyrin functions to sense pathogen modification and inactivation of Rho GTPases, representing a new paradigm in mammalian innate immunity.
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Popoff MR. Bacterial factors exploit eukaryotic Rho GTPase signaling cascades to promote invasion and proliferation within their host. Small GTPases 2014; 5:28209. [PMID: 25203748 DOI: 10.4161/sgtp.28209] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Actin cytoskeleton is a main target of many bacterial pathogens. Among the multiple regulation steps of the actin cytoskeleton, bacterial factors interact preferentially with RhoGTPases. Pathogens secrete either toxins which diffuse in the surrounding environment, or directly inject virulence factors into target cells. Bacterial toxins, which interfere with RhoGTPases, and to some extent with RasGTPases, catalyze a covalent modification (ADPribosylation, glucosylation, deamidation, adenylation, proteolysis) blocking these molecules in their active or inactive state, resulting in alteration of epithelial and/or endothelial barriers, which contributes to dissemination of bacteria in the host. Injected bacterial virulence factors preferentially manipulate the RhoGTPase signaling cascade by mimicry of eukaryotic regulatory proteins leading to local actin cytoskeleton rearrangement, which mediates bacterial entry into host cells or in contrast escape to phagocytosis and immune defense. Invasive bacteria can also manipulate RhoGTPase signaling through recognition and stimulation of cell surface receptor(s). Changes in RhoGTPase activation state is sensed by the innate immunity pathways and allows the host cell to adapt an appropriate defense response.
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Affiliation(s)
- Michel R Popoff
- Unité des Bactéries anaérobies et Toxines; Institut Pasteur; Paris, France
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29
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LRP1 is a receptor for Clostridium perfringens TpeL toxin indicating a two-receptor model of clostridial glycosylating toxins. Proc Natl Acad Sci U S A 2014; 111:6431-6. [PMID: 24737893 DOI: 10.1073/pnas.1323790111] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Large glycosylating toxins are major virulence factors of various species of pathogenic Clostridia. Prototypes are Clostridium difficile toxins A and B, which cause antibiotics-associated diarrhea and pseudomembranous colitis. The current model of the toxins' action suggests that receptor binding is mediated by a C-terminal domain of combined repetitive oligopeptides (CROP). This model is challenged by the glycosylating Clostridium perfringens large cytotoxin (TpeL toxin) that is devoid of the CROP domain but still intoxicates cells. Using a haploid genetic screen, we identified LDL receptor-related protein 1 (LRP1) as a host cell receptor for the TpeL toxin. LRP1-deficient cells are not able to take up TpeL and are not intoxicated. Expression of cluster IV of LRP1 is sufficient to rescue toxin uptake in these cells. By plasmon resonance spectroscopy, a KD value of 23 nM was determined for binding of TpeL to LRP1 cluster IV. The C terminus of TpeL (residues 1335-1779) represents the receptor-binding domain (RBD) of the toxin. RBD-like regions are conserved in all other clostridial glycosylating toxins preceding their CROP domain. CROP-deficient C. difficile toxin B is toxic to cells, depending on the RBD-like region (residues 1349-1811) but does not interact with LRP1. Our data indicate the presence of a second, CROP-independent receptor-binding domain in clostridial glycosylating toxins and suggest a two-receptor model for the cellular uptake of clostridial glycosylating toxins.
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30
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Pauillac S, D'allayer J, Lenormand P, Rousselle JC, Bouvet P, Popoff MR. Characterization of the enzymatic activity of Clostridium perfringens TpeL. Toxicon 2013; 75:136-43. [PMID: 23851225 DOI: 10.1016/j.toxicon.2013.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 06/25/2013] [Accepted: 07/02/2013] [Indexed: 01/01/2023]
Abstract
TpeL is a toxin produced by Clostridium perfringens which belongs to the large clostridial glucosylating toxin family. It was shown that TpeL modifies Ras using UDP-glucose or UDP-N-acetylglucosamine as cosubstrates (Guttenberg et al., 2012; Nagahama et al., 2011). We confirmed that TpeL preferentially glucosaminates the three isoforms of Ras (cH-Ras, N-Ras, and K-Ras) from UDP-N-acetylglucosamine and to a lower extent Rap1a and R-Ras3, and very weakly Rac1. In contrast to previous report, we observed that Ral was not a substrate of TpeL. In addition, we confirmed by in vitro glucosylation and mass spectrometry that TpeL modifies cH-Ras at Thr35.
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Affiliation(s)
- Serge Pauillac
- Institut Pasteur, Unité des Bactéries anaérobies et Toxines, 25 rue du Dr Roux, 75724 Paris Cedex 15, France
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31
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Zeiser J, Gerhard R, Just I, Pich A. Substrate specificity of clostridial glucosylating toxins and their function on colonocytes analyzed by proteomics techniques. J Proteome Res 2013; 12:1604-18. [PMID: 23387933 DOI: 10.1021/pr300973q] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Clostridium difficile is the major cause of intestinal infections in hospitals. The major virulence factors are toxin A (TcdA) and toxin B (TcdB), which belong to the group of clostridial glucosylating toxins (CGT) that inactivate small GTPases. After a 24 h incubation period with TcdA or a glucosyltransferase-deficient mutant TcdA (gdTcdA), quantitative changes in the proteome of colonic cells (Caco-2) were analyzed using high-resolution LC-MS/MS and the SILAC technique. The changes in abundance of more than 5100 proteins were quantified. Nearly 800 toxin-responsive proteins were identified that were involved in cell cycle, cell structure, and adhesion as well as metabolic processes. Several proteins localized to mitochondria or involved in lipid metabolism were consistently of higher abundance after TcdA treatment. All changes of protein abundance depended on the glucosyltransferase activity of TcdA. Glucosylation of the known targets of TcdA such as RhoA, RhoC, RhoG was detected by LC-MS/MS. In addition, an almost complete glucosylation of Rap1(A/B), Rap2(A/B/C) and a partial glucosylation of Ral(A/B) and (H/K/N)Ras were detected. The glucosylation pattern of TcdA was compared to that of other CGT like TcdB, the variant TcdB from C. difficile strain VPI 1470 (TcdBF), and lethal toxin from C. sordellii (TcsL).
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Affiliation(s)
- Johannes Zeiser
- Hannover Medical School, Institute of Toxicology , Carl-Neuberg-Str. 1, 30625 Hannover, Germany
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32
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Zeidán-Chuliá F, Rybarczyk-Filho JL, Salmina AB, de Oliveira BHN, Noda M, Moreira JCF. Exploring the Multifactorial Nature of Autism Through Computational Systems Biology: Calcium and the Rho GTPase RAC1 Under the Spotlight. Neuromolecular Med 2013; 15:364-83. [DOI: 10.1007/s12017-013-8224-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 02/16/2013] [Indexed: 01/08/2023]
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Guttenberg G, Hornei S, Jank T, Schwan C, Lü W, Einsle O, Papatheodorou P, Aktories K. Molecular characteristics of Clostridium perfringens TpeL toxin and consequences of mono-O-GlcNAcylation of Ras in living cells. J Biol Chem 2012; 287:24929-40. [PMID: 22665487 DOI: 10.1074/jbc.m112.347773] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
TpeL is a member of the family of clostridial glucosylating toxins produced by Clostridium perfringens type A, B, and C strains. In contrast to other members of this toxin family, it lacks a C-terminal polypeptide repeat domain, which is suggested to be involved in target cell binding. It was shown that the glucosyltransferase domain of TpeL modifies Ras in vitro by mono-O-glucosylation or mono-O-GlcNAcylation (Nagahama, M., Ohkubo, A., Oda, M., Kobayashi, K., Amimoto, K., Miyamoto, K., and Sakurai, J. (2011) Infect. Immun. 79, 905-910). Here we show that TpeL preferably utilizes UDP-N-acetylglucosamine (UDP-GlcNAc) as a sugar donor. Change of alanine 383 of TpeL to isoleucine turns the sugar donor preference from UDP-GlcNAc to UDP-glucose. In contrast to previous studies, we show that Rac is a poor substrate in vitro and in vivo and requires 1-2 magnitudes higher toxin concentrations for modification by TpeL. The toxin is autoproteolytically processed in the presence of inositol hexakisphosphate (InsP(6)) by an intrinsic cysteine protease domain, located next to the glucosyltransferase domain. A C-terminally extended TpeL full-length variant (TpeL1-1779) induces apoptosis in HeLa cells (most likely by mono-O-GlcNAcylation of Ras), and inhibits Ras signaling including Ras-Raf interaction and ERK activation. In addition, TpeL blocks Ras signaling in rat pheochromocytoma PC12 cells. TpeL is a glucosylating toxin, which modifies Ras and induces apoptosis in target cells without having a typical C-terminal polypeptide repeat domain.
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Affiliation(s)
- Gregor Guttenberg
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany
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Faust D, Schmitt C, Oesch F, Oesch-Bartlomowicz B, Schreck I, Weiss C, Dietrich C. Differential p38-dependent signalling in response to cellular stress and mitogenic stimulation in fibroblasts. Cell Commun Signal 2012; 10:6. [PMID: 22404972 PMCID: PMC3352310 DOI: 10.1186/1478-811x-10-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 03/09/2012] [Indexed: 01/07/2023] Open
Abstract
p38 MAP kinase is known to be activated by cellular stress finally leading to cell cycle arrest or apoptosis. Furthermore, a tumour suppressor role of p38 MAPK has been proposed. In contrast, a requirement of p38 for proliferation has also been described. To clarify this paradox, we investigated stress- and mitogen-induced p38 signalling in the same cell type using fibroblasts. We demonstrate that - in the same cell line - p38 is activated by mitogens or cellular stress, but p38-dependent signalling is different. Exposure to cellular stress, such as anisomycin, leads to a strong and persistent p38 activation independent of GTPases. As a result, MK2 and downstream the transcription factor CREB are phosphorylated. In contrast, mitogenic stimulation results in a weaker and transient p38 activation, which upstream involves small GTPases and is required for cyclin D1 induction. Consequently, the retinoblastoma protein is phosphorylated and allows G1/S transition. Our data suggest a dual role of p38 and indicate that the level and/or duration of p38 activation determines the cellular response, i.e either proliferation or cell cycle arrest.
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Affiliation(s)
- Dagmar Faust
- Institute of Toxicology, Medical Center of the Johannes Gutenberg-University, Obere Zahlbacherstr, 67, 55131 Mainz, Germany.
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35
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Popoff MR. Multifaceted interactions of bacterial toxins with the gastrointestinal mucosa. Future Microbiol 2011; 6:763-97. [PMID: 21797691 DOI: 10.2217/fmb.11.58] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The digestive tract is one of the ecosystems that harbors the largest number and greatest variety of bacteria. Among them, certain bacteria have developed various strategies, including the synthesis of virulence factors such as toxins, to interact with the intestinal mucosa, and are responsible for various pathologies. A large variety of bacterial toxins of different sizes, structures and modes of action are able to interact with the gastrointestinal mucosa. Some toxins, termed enterotoxins, directly stimulate fluid secretion in enterocytes or cause their death, whereas other toxins pass through the intestinal barrier and disseminate by the general circulation to remote organs or tissues, where they are active. After recognition of a membrane receptor on target cells, toxins can act at the cell membrane by transducing a signal across the membrane in a hormone-like manner, by pore formation or by damaging membrane compounds. Other toxins can enter the cells and modify an intracellular target leading to a disregulation of certain physiological processes or disorganization of some structural architectures and cell death. Toxins are fascinating molecules, which mimic or interfere with eukaryotic physiological processes. Thereby, they have permitted the identification and characterization of new natural hormones or regulatory pathways. Besides use as protective antigens in vaccines, toxins offer multiple possibilities in pharmacology, such as immune modulation or specific delivery of a protein of interest into target cells.
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Affiliation(s)
- M R Popoff
- Institut Pasteur, Unité des Bactéries anaérobies et Toxines, 25 rue du Dr Roux, 757245 Paris cedex 15, France.
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Abstract
Many bacterial pathogens produce protein toxins to outmanoeuvre the immune system of the host. Some of these proteins target regulatory GTPases such as those belonging to the RHO family, which control the actin cytoskeleton of the host cell. In this Review, I discuss a diversity of mechanisms that are used by bacterial effectors and toxins to modulate the activity of host GTPases, with a focus on covalent modifications such as ADP-ribosylation, glucosylation, adenylylation, proteolysis, deamidation and transglutamination.
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Affiliation(s)
- Klaus Aktories
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, Albertstr. 25, 79104 Freiburg, Germany.
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Guttenberg G, Papatheodorou P, Genisyuerek S, Lü W, Jank T, Einsle O, Aktories K. Inositol hexakisphosphate-dependent processing of Clostridium sordellii lethal toxin and Clostridium novyi alpha-toxin. J Biol Chem 2011; 286:14779-86. [PMID: 21385871 DOI: 10.1074/jbc.m110.200691] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Clostridium sordellii lethal toxin and Clostridium novyi α-toxin, which are virulence factors involved in the toxic shock and gas gangrene syndromes, are members of the family of clostridial glucosylating toxins. The toxins inactivate Rho/Ras proteins by glucosylation or attachment of GlcNAc (α-toxin). Here, we studied the activation of the autoproteolytic processing of the toxins by inositol hexakisphosphate (InsP(6)) and compared it with the processing of Clostridium difficile toxin B. In the presence of low concentrations of InsP(6) (<1 μM), toxin fragments consisting of the N-terminal glucosyltransferase (or GlcNAc-transferase) domains and the cysteine protease domains (CPDs) of C. sordellii lethal toxin, C. novyi α-toxin, and C. difficile toxin B were autocatalytically processed. The cleavage sites of lethal toxin (Leu-543) and α-toxin (Leu-548) and the catalytic cysteine residues (Cys-698 of lethal toxin and Cys-707 of α-toxin) were identified. Affinity of the CPDs for binding InsP(6) was determined by isothermal titration calorimetry. In contrast to full-length toxin B and α-toxin, autocatalytic cleavage and InsP(6) binding of full-length lethal toxin depended on low pH (pH 5) conditions. The data indicate that C. sordellii lethal toxin and C. novyi α-toxin are InsP(6)-dependently processed. However, full-length lethal toxin, but not its short toxin fragments consisting of the glucosyltransferase domain and the CPD, requires a pH-sensitive conformational change to allow binding of InsP(6) and subsequent processing of the toxin.
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Affiliation(s)
- Gregor Guttenberg
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany
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Popoff MR, Geny B. Rho/Ras-GTPase-dependent and -independent activity of clostridial glucosylating toxins. J Med Microbiol 2011; 60:1057-1069. [PMID: 21349986 DOI: 10.1099/jmm.0.029314-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Clostridial glucosylating toxins are the main virulence factors of clostridia responsible for gangrene and/or colitis. These toxins have been well characterized to inactivate Rho/Ras-GTPases through glucosylation. However, the signalling pathways downstream of Rho/Ras-GTPases leading to the intracellular effects of these toxins are only partially known. Rac-dependent modification of focal adhesion complexes and phosphoinositide metabolism seem to be key processes involved in actin filament depolymerization and disorganization of intercellular junctions. In addition, clostridial glucosylating toxins induce Rho/Ras-independent intracellular effects such as activation of mitogen-activated protein kinase pathways, which are used by some of these toxins to trigger an inflammatory response.
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Affiliation(s)
- Michel R Popoff
- Institut Pasteur, Unité des Bactéries Anaérobies et Toxines, 25 rue du Dr Roux, 75724 Paris cedex 15, France
| | - Bladine Geny
- Institut Pasteur, Unité des Bactéries Anaérobies et Toxines, 25 rue du Dr Roux, 75724 Paris cedex 15, France
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Functional implications of lethal toxin-catalysed glucosylation of (H/K/N)Ras and Rac1 in Clostridium sordellii-associated disease. Eur J Cell Biol 2010; 90:959-65. [PMID: 21134703 DOI: 10.1016/j.ejcb.2010.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 10/19/2010] [Accepted: 10/19/2010] [Indexed: 11/20/2022] Open
Abstract
Clostridium sordellii-based diseases in humans and livestock rely on the activity of the major virulence factors, the single-chain protein toxins TcsL and TcsH, both belonging to the large clostridial glucosylating toxins. TcsL exclusively glucosylates Rho and Ras low molecular weight GTP-binding proteins. TcsL-induced loss of barrier function in epithelial (diarrhoea) and endothelial cells (extravasation of blood fluid) is based on Rac glucosylation whereas induction of apoptosis results from glucosylation of Ras. Intracellular glucosylation of Rac and Ras can be tracked by immunoblot applying the glucosylation-sensitive antibodies Rac1(Mab 102) and Ras(Mab 27H5). Induction of apoptosis especially of phagocytotic cells is crucial for the severity of C. sordellii-associated disease. The inhibition of TcsL-induced apoptosis by tauroursodeoxycholic acid (TUDCA) may be a promising therapeutic option.
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Wilson BA, Ho M. Recent insights into Pasteurella multocida toxin and other G-protein-modulating bacterial toxins. Future Microbiol 2010; 5:1185-201. [PMID: 20722598 DOI: 10.2217/fmb.10.91] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Over the past few decades, our understanding of the bacterial protein toxins that modulate G proteins has advanced tremendously through extensive biochemical and structural analyses. This article provides an updated survey of the various toxins that target G proteins, ending with a focus on recent mechanistic insights in our understanding of the deamidating toxin family. The dermonecrotic toxin from Pasteurella multocida (PMT) was recently added to the list of toxins that disrupt G-protein signal transduction through selective deamidation of their targets. The C3 deamidase domain of PMT has no sequence similarity to the deamidase domains of the dermonecrotic toxins from Escherichia coli (cytotoxic necrotizing factor [CNF]1-3), Yersinia (CNFY) and Bordetella (dermonecrotic toxin). The structure of PMT-C3 belongs to a family of transglutaminase-like proteins, with active site Cys-His-Asp catalytic triads distinct from E. coli CNF1.
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Affiliation(s)
- Brenda A Wilson
- Department of Microbiology and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave, B128 CLSL, Urbana, IL 61801, USA.
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Dreger SC, Schulz F, Huelsenbeck J, Gerhard R, Hofmann F, Just I, Genth H. Killing of rat basophilic leukemia cells by lethal toxin from Clostridium sordellii: critical role of phosphatidylinositide 3'-OH kinase/Akt signaling. Biochemistry 2010; 48:1785-92. [PMID: 19199813 DOI: 10.1021/bi800708b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Clostridium sordellii lethal toxin (TcsL) belongs to the family of clostridial glucosylating toxins. TcsL exhibits glucosyltransferase activity to inactivate Rho and Ras proteins. On cultured cells, TcsL causes actin reorganization ("cytopathic effect") and apoptotic cell death ("cytotoxic effect"). This study is based on the concept that the cytotoxic effects of TcsL depend on the glucosylation of critical substrate proteins rather than on the glucosyltransferase activity per se. The cytotoxic effects of TcsL depend on the glucosyltransferase activity of TcsL, as neither chemically inactivated TcsL nor a glucosyltransferase-deficient mutant version of TcsL caused it. The TcsL homologous toxin B from Clostridium difficile serotype F strain 1470 (TcdBF) also failed to cause cytotoxic effects. Correlation of the toxins' respective protein substrate specificities highlighted (H/K/N)Ras as critical substrate proteins for the cytotoxic effects. (H/K/N)Ras are critical upstream regulators of phosphatidylinositide 3'-OH kinase (PI3K)/Akt survival signaling. Tauroursodeoxycholic acid (TUDCA) classified to activate PI3K/Akt signaling downstream of apoptosis-inducing stimuli prevented the cytotoxic effects of TcsL. In conclusion, (H/K/N)Ras glucosylation and subsequent inhibition of PI3K/Akt signaling are critical for the cytotoxic effects of TcsL.
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Affiliation(s)
- Stefanie C Dreger
- Institut für Toxikologie, Medizinische Hochschule Hannover, D-30625 Hannover, Germany
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Popoff MR, Poulain B. Bacterial toxins and the nervous system: neurotoxins and multipotential toxins interacting with neuronal cells. Toxins (Basel) 2010; 2:683-737. [PMID: 22069606 PMCID: PMC3153206 DOI: 10.3390/toxins2040683] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2010] [Revised: 03/18/2010] [Accepted: 04/07/2010] [Indexed: 12/13/2022] Open
Abstract
Toxins are potent molecules used by various bacteria to interact with a host organism. Some of them specifically act on neuronal cells (clostridial neurotoxins) leading to characteristics neurological affections. But many other toxins are multifunctional and recognize a wider range of cell types including neuronal cells. Various enterotoxins interact with the enteric nervous system, for example by stimulating afferent neurons or inducing neurotransmitter release from enterochromaffin cells which result either in vomiting, in amplification of the diarrhea, or in intestinal inflammation process. Other toxins can pass the blood brain barrier and directly act on specific neurons.
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Affiliation(s)
- Michel R. Popoff
- Neurotransmission et Sécrétion Neuroendocrine, CNRS UPR 2356 IFR 37 - Neurosciences, Centre de Neurochimie, 5, rue Blaise Pascal, F-67084 STRASBOURG cedex, France;
- Author to whom correspondence should be addressed;
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Abstract
Small GTPases of the Rho protein family are master regulators of the actin cytoskeleton and are targeted by potent virulence factors of several pathogenic bacteria. Their dysfunctional regulation can lead to severe human pathologies. Both host and bacterial factors can activate or inactivate Rho proteins by direct post-translational modifications: such as deamidation and transglutamination for activation, or ADP-ribosylation, glucosylation, adenylylation and phosphorylation for inactivation. We review and compare these unconventional ways in which both host cells and bacterial pathogens regulate Rho proteins.
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Belyi Y, Aktories K. Bacterial toxin and effector glycosyltransferases. Biochim Biophys Acta Gen Subj 2010; 1800:134-43. [DOI: 10.1016/j.bbagen.2009.07.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 07/14/2009] [Accepted: 07/18/2009] [Indexed: 02/08/2023]
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Abstract
Clostridia produce the highest number of toxins of any type of bacteria and are involved in severe diseases in humans and other animals. Most of the clostridial toxins are pore-forming toxins responsible for gangrenes and gastrointestinal diseases. Among them, perfringolysin has been extensively studied and it is the paradigm of the cholesterol-dependent cytolysins, whereas Clostridium perfringens epsilon-toxin and Clostridium septicum alpha-toxin, which are related to aerolysin, are the prototypes of clostridial toxins that form small pores. Other toxins active on the cell surface possess an enzymatic activity, such as phospholipase C and collagenase, and are involved in the degradation of specific cell-membrane or extracellular-matrix components. Three groups of clostridial toxins have the ability to enter cells: large clostridial glucosylating toxins, binary toxins and neurotoxins. The binary and large clostridial glucosylating toxins alter the actin cytoskeleton by enzymatically modifying the actin monomers and the regulatory proteins from the Rho family, respectively. Clostridial neurotoxins proteolyse key components of neuroexocytosis. Botulinum neurotoxins inhibit neurotransmission at neuromuscular junctions, whereas tetanus toxin targets the inhibitory interneurons of the CNS. The high potency of clostridial toxins results from their specific targets, which have an essential cellular function, and from the type of modification that they induce. In addition, clostridial toxins are useful pharmacological and biological tools.
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Affiliation(s)
- Michel R Popoff
- Institut Pasteur, Bactéries Anaérobies et Toxines, 75724 Paris cedex 15, France.
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Abstract
The endothelium lining blood and lymphatic vessels is a key barrier separating body fluids from host tissues and is a major target of pathogenic bacteria. Endothelial cells are actively involved in host responses to infectious agents, producing inflammatory cytokines, controlling coagulation cascades and regulating leukocyte trafficking. In this Review, a range of bacteria and bacterial toxins are used to illustrate how pathogens establish intimate interactions with endothelial cells, triggering inflammatory responses and coagulation processes and modifying endothelial cell plasma membranes and junctions to adhere to their surfaces and then invade, cross and even disrupt the endothelial barrier.
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Geny B, Grassart A, Manich M, Chicanne G, Payrastre B, Sauvonnet N, Popoff MR. Rac1 inactivation by lethal toxin from Clostridium sordellii modifies focal adhesions upstream of actin depolymerization. Cell Microbiol 2009; 12:217-32. [PMID: 19840028 DOI: 10.1111/j.1462-5822.2009.01392.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inactivation of different small GTPases upon their glucosylation by lethal toxin from Clostridium sordellii strain IP82 (LT-82) is already known to lead to cell rounding, adherens junction (AJ) disorganization and actin depolymerization. In the present work, we observed that LT-82 induces a rapid dephosphorylation of paxillin, a protein regulating focal adhesion (FA), independently of inactivation of paxillin kinases such as Src, Fak and Pyk2. Among the small GTPases inactivated by this toxin, including Rac, Ras, Rap and Ral, we identified Rac1, as responsible for paxillin dephosphorylation using cells overexpressing Rac1(V12). Rac1 inactivation by LT-82 modifies interactions between proteins from AJ and FA complexes as shown by pull-down assays. We showed that in Triton X-100-insoluble membrane proteins from these complexes, namely E-cadherin, beta-catenin, p120-catenin and talin, are decreased upon LT-82 intoxication, a treatment that also induces a rapid decrease in cell phosphoinositide content. Therefore, we proposed that Rac inactivation by LT-82 alters phosphoinositide metabolism leading to FA and AJ complex disorganization and actin depolymerization.
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Affiliation(s)
- Blandine Geny
- Unité des Bactéries Anaérobies et Toxines, Department of Microbiology, Institut Pasteur, 25 rue du Docteur Roux, Paris Cedex 15, France.
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Huelsenbeck SC, Klose I, Reichenbach M, Huelsenbeck J, Genth H. Distinct kinetics of (H/K/N)Ras glucosylation and Rac1 glucosylation catalysed by Clostridium sordellii lethal toxin. FEBS Lett 2009; 583:3133-9. [PMID: 19744486 DOI: 10.1016/j.febslet.2009.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 08/24/2009] [Accepted: 09/01/2009] [Indexed: 10/20/2022]
Abstract
Mono-glucosylation of (H/K/N)Ras by Clostridium sordellii lethal toxin (TcsL) blocks critical survival signaling pathways, resulting in apoptotic cell death. One yet unsolved problem in studies on TcsL is the lack of a method allowing the specific detection of (H/K/N)Ras glucosylation. In this study, we identify the Ras(Mab 27H5) antibody as a glucosylation-sensitive antibody capable for the immunoblot detection of (H/K/N)Ras glucosylation in TcsL-treated cells. Alternative Ras antibodies including the K-Ras(Mab F234) antibody or the v-H-Ras(Mab Y13-159) antibody recognize Ras proteins regardless of glucosylation. (H/K)Ras are further shown to be more efficaciously glucosylated by TcsL than Rac1 in rat basophilic leukemia cells as well as in a cell-free system.
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Geny B, Popoff MR. Activation of a c-Jun-NH2-terminal kinase pathway by the lethal toxin fromClostridium sordellii, TcsL-82, occurs independently of the toxin intrinsic enzymatic activity and facilitates small GTPase glucosylation. Cell Microbiol 2009; 11:1102-13. [DOI: 10.1111/j.1462-5822.2009.01314.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Jank T, Ziegler MOP, Schulz GE, Aktories K. Inhibition of the glucosyltransferase activity of clostridial Rho/Ras-glucosylating toxins by castanospermine. FEBS Lett 2008; 582:2277-82. [PMID: 18505687 DOI: 10.1016/j.febslet.2008.05.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 05/16/2008] [Accepted: 05/19/2008] [Indexed: 01/25/2023]
Abstract
Castanospermine was identified as an inhibitor of the Rho/Ras-glucosylating Clostridium sordellii lethal toxin and Clostridium difficile toxin B. Microinjection of castanospermine into embryonic bovine lung cells prevented the cytotoxic effects of toxins. The crystal structure of the glucosyltransferase domain of C. sordellii lethal toxin in complex with castanospermine, UDP and a calcium ion was solved at a resolution of 2.3A. The inhibitor binds in a conformation that brings its four hydroxyl groups and its N-atom almost exactly in the positions of the four hydroxyls and of the ring oxygen of the glucosyl moiety of UDP-glucose, respectively.
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Affiliation(s)
- Thomas Jank
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Albertstrasse 25, Freiburg, Germany
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