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Zheng R, Li W, Yin W, Qiao L, Song S, An Y, Ling Z, Bai L, Yang H, Shen J, Dong Y, Wang Y. PEtN-Modified O-Antigen Enhances Shigella Pathogenesis by Promoting Epithelial Cell Invasion and Inhibiting Complement Binding. ACS Infect Dis 2024; 10:377-383. [PMID: 38252850 DOI: 10.1021/acsinfecdis.3c00602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Shigellosis poses an ongoing global public health threat. The presence and length of the O-antigen in lipopolysaccharide play critical roles in Shigella pathogenesis. The plasmid-mediated opt gene encodes a phosphoethanolamine (PEtN) transferase that catalyzes the addition of PEtN to the O-antigen of Shigella flexneri serotype X and Y strains, converting them into serotype Xv and Yv strains, respectively. Since 2002, these modified strains have become prevalent in China. Here we demonstrate that PEtN-mediated O-antigen modification in S. flexneri increase the severity of corneal infection in guinea pigs without any adaptive cost. This heightened virulence is associated with epithelial cell adhesion and invasion, as well as an enhanced inflammatory response of macrophage. Notably, PEtN addition allow S. flexneri to attenuate the binding of complement C3 and better resist phagocytosis, potentially contributing to the retention of S. flexneri in the host environment.
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Affiliation(s)
- Ruicheng Zheng
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Wan Li
- School of Basic Medicine, Shenzhen University, Shenzhen, Guangdong 518055, China
| | - Wenjuan Yin
- School of Basic Medicine, Hebei University, Baoding, Hebei 071000, China
| | - Lu Qiao
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Shikai Song
- Poultry Institute, Shandong Academy of Agricultural Science, Jinan, Shandong 250100, China
| | - Yina An
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Zhuoren Ling
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Li Bai
- NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100021, China
| | - Hui Yang
- NHC Key Laboratory of Food Safety Risk Assessment, China National Center for Food Safety Risk Assessment, Beijing 100021, China
| | - Jianzhong Shen
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yanjun Dong
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yang Wang
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
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2
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Chang YY, Valenzuela C, Lensen A, Lopez-Montero N, Sidik S, Salogiannis J, Enninga J, Rohde J. Microtubules provide force to promote membrane uncoating in vacuolar escape for a cyto-invasive bacterial pathogen. Nat Commun 2024; 15:1065. [PMID: 38316786 PMCID: PMC10844605 DOI: 10.1038/s41467-024-45182-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 01/15/2024] [Indexed: 02/07/2024] Open
Abstract
Intracellular bacterial pathogens gain entry to mammalian cells inside a vacuole derived from the host membrane. Some of them escape the bacteria-containing vacuole (BCV) and colonize the cytosol. Bacteria replicating within BCVs coopt the microtubule network to position it within infected cells, whereas the role of microtubules for cyto-invasive pathogens remains obscure. Here, we show that the microtubule motor cytoplasmic dynein-1 and specific activating adaptors are hijacked by the enterobacterium Shigella flexneri. These host proteins were found on infection-associated macropinosomes (IAMs) formed during Shigella internalization. We identified Rab8 and Rab13 as mediators of dynein recruitment and discovered that the Shigella effector protein IpaH7.8 promotes Rab13 retention on moving BCV membrane remnants, thereby facilitating membrane uncoating of the Shigella-containing vacuole. Moreover, the efficient unpeeling of BCV remnants contributes to a successful intercellular spread. Taken together, our work demonstrates how a bacterial pathogen subverts the intracellular transport machinery to secure a cytosolic niche.
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Affiliation(s)
- Yuen-Yan Chang
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Camila Valenzuela
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
| | - Arthur Lensen
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
| | - Noelia Lopez-Montero
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
| | - Saima Sidik
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
| | - John Salogiannis
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, USA
| | - Jost Enninga
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France.
| | - John Rohde
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada.
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Torraca V, White RJ, Sealy IM, Mazon-Moya M, Duggan G, Willis AR, Busch-Nentwich EM, Mostowy S. Transcriptional profiling of zebrafish identifies host factors controlling susceptibility to Shigella flexneri. Dis Model Mech 2024; 17:dmm050431. [PMID: 38131137 PMCID: PMC10846535 DOI: 10.1242/dmm.050431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023] Open
Abstract
Shigella flexneri is a human-adapted pathovar of Escherichia coli that can invade the intestinal epithelium, causing inflammation and bacillary dysentery. Although an important human pathogen, the host response to S. flexneri has not been fully described. Zebrafish larvae represent a valuable model for studying human infections in vivo. Here, we use a Shigella-zebrafish infection model to generate mRNA expression profiles of host response to Shigella infection at the whole-animal level. Immune response-related processes dominate the signature of early Shigella infection (6 h post-infection). Consistent with its clearance from the host, the signature of late Shigella infection (24 h post-infection) is significantly changed, and only a small set of immune-related genes remain differentially expressed, including acod1 and gpr84. Using mutant lines generated by ENU, CRISPR mutagenesis and F0 crispants, we show that acod1- and gpr84-deficient larvae are more susceptible to Shigella infection. Together, these results highlight the power of zebrafish to model infection by bacterial pathogens and reveal the mRNA expression of the early (acutely infected) and late (clearing) host response to Shigella infection.
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Affiliation(s)
- Vincenzo Torraca
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London SE1 9RT, UK
- School of Life Sciences, University of Westminster, London W1W 6UW, UK
| | - Richard J. White
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge CB2 0AW, UK
- School of Biological and Behavioural Sciences, Faculty of Science and Engineering, Queen Mary University of London, London E1 4NS, UK
| | - Ian M. Sealy
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge CB2 0AW, UK
- School of Biological and Behavioural Sciences, Faculty of Science and Engineering, Queen Mary University of London, London E1 4NS, UK
| | - Maria Mazon-Moya
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Gina Duggan
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Alexandra R. Willis
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Elisabeth M. Busch-Nentwich
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge, Cambridge CB2 0AW, UK
- School of Biological and Behavioural Sciences, Faculty of Science and Engineering, Queen Mary University of London, London E1 4NS, UK
| | - Serge Mostowy
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
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4
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Ascari A, Frölich S, Zang M, Tran ENH, Wilson DW, Morona R, Eijkelkamp BA. Shigella flexneri remodeling and consumption of host lipids during infection. J Bacteriol 2023; 205:e0032023. [PMID: 37991380 PMCID: PMC10729657 DOI: 10.1128/jb.00320-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/10/2023] [Indexed: 11/23/2023] Open
Abstract
IMPORTANCE Bacterial pathogens have vastly distinct sites that they inhabit during infection. This requires adaptation due to changes in nutrient availability and antimicrobial stress. The bacterial surface is a primary barrier, and here, we show that the bacterial pathogen Shigella flexneri increases its surface decorations when it transitions to an intracellular lifestyle. We also observed changes in bacterial and host cell fatty acid homeostasis. Specifically, intracellular S. flexneri increased the expression of their fatty acid degradation pathway, while the host cell lipid pool was significantly depleted. Importantly, bacterial proliferation could be inhibited by fatty acid supplementation of host cells, thereby providing novel insights into the possible link between human malnutrition and susceptibility to S. flexneri.
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Affiliation(s)
- Alice Ascari
- Department of Molecular and Biomedical Science, School of Biological Sciences, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, Australia
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Adelaide, Australia
| | - Sonja Frölich
- Department of Molecular and Biomedical Science, School of Biological Sciences, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, Australia
- Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, Australia
| | - Maoge Zang
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Adelaide, Australia
| | - Elizabeth N. H. Tran
- Department of Molecular and Biomedical Science, School of Biological Sciences, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, Australia
| | - Danny W. Wilson
- Department of Molecular and Biomedical Science, School of Biological Sciences, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, Australia
- Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, Australia
| | - Renato Morona
- Department of Molecular and Biomedical Science, School of Biological Sciences, Research Centre for Infectious Diseases, University of Adelaide, Adelaide, Australia
| | - Bart A. Eijkelkamp
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Adelaide, Australia
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5
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Trirocco R, Pasqua M, Tramonti A, Colonna B, Paiardini A, Prosseda G. Diffusible signal factors (DSFs) bind and repress VirF, the leading virulence activator of Shigella flexneri. Sci Rep 2023; 13:13170. [PMID: 37580399 PMCID: PMC10425336 DOI: 10.1038/s41598-023-40023-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/03/2023] [Indexed: 08/16/2023] Open
Abstract
Shigella, the aetiological agent of human bacillary dysentery, controls the expression of its virulence determinants through an environmentally stimulated cascade of transcriptional activators. VirF is the leading activator and is essential for proper virulence expression. In this work, we report on in vitro and in vivo experiments showing that two autoinducers of the DSF family, XcDSF and BDSF interact with the jelly roll module of VirF causing its inhibition and affecting the expression of the entire virulence system of Shigella, including its ability to invade epithelial cells. We propose a molecular model explaining how the binding of XcDSF and BDSF causes inhibition of VirF by preventing its dimerization. Overall, our experimental results suggest that XcDSF and BDSF may contribute to "colonisation resistance" in the human gut or, alternatively, may be exploited for the fine-tuning of Shigella virulence expression as the bacterium migrates from the lumen to approach the intestinal mucosa. Our findings also stress how a detailed understanding of the interaction of DSF ligands with VirF may contribute to the rational development of innovative antivirulence drugs to treat shigellosis.
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Affiliation(s)
- Rita Trirocco
- Institute Pasteur Italia, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy
| | - Martina Pasqua
- Institute Pasteur Italia, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy
| | - Angela Tramonti
- Institute of Molecular Biology and Pathology, National Research Council, Rome, Italy
| | - Bianca Colonna
- Institute Pasteur Italia, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy
| | - Alessandro Paiardini
- Department of Biochemical Sciences, Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy
| | - Gianni Prosseda
- Institute Pasteur Italia, Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, p.le Aldo Moro 5, 00185, Rome, Italy.
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6
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Ascari A, Waters JK, Morona R, Eijkelkamp BA. Shigella flexneri Adapts to Niche-Specific Stresses through Modifications in Cell Envelope Composition and Decoration. ACS Infect Dis 2023; 9:1610-1621. [PMID: 37494550 DOI: 10.1021/acsinfecdis.3c00210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Shigella flexneri is the primary causative agent of worldwide shigellosis. As the pathogen transverses the distinct niches of the gastrointestinal tract it necessitates dynamic adaptation strategies to mitigate host antimicrobials such as dietary fatty acids (FAs) and the bile salt, deoxycholate (DOC). This study investigates the dynamics of the S. flexneri cell envelope, by interrogating adaptations following FA or DOC exposure. We deciphered the effects of FAs and DOC on bacterial membrane fatty acid and lipopolysaccharide (LPS) compositions. We identified novel LPS-based strategies by the pathogen to support resistance to these host compounds. In particular, expression of S. flexneri very-long O antigen (VL-Oag) LPS was found to play a central role in stress mitigation, as VL-Oag protects against antimicrobial FAs, but its presence rendered S. flexneri susceptible to DOC stress. Collectively, this work underpins the importance for S. flexneri to maintain appropriate regulation of cell envelope constituents, in particular VL-Oag LPS, to adequately adapt to diverse stresses during infection.
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Affiliation(s)
- Alice Ascari
- School of Biological Sciences, Department of Molecular and Biomedical Science, Research Centre for Infectious Diseases, University of Adelaide, Adelaide 5005, South Australia, Australia
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Adelaide 5042, South Australia, Australia
| | - Jack K Waters
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Adelaide 5042, South Australia, Australia
| | - Renato Morona
- School of Biological Sciences, Department of Molecular and Biomedical Science, Research Centre for Infectious Diseases, University of Adelaide, Adelaide 5005, South Australia, Australia
| | - Bart A Eijkelkamp
- Molecular Sciences and Technology, College of Science and Engineering, Flinders University, Adelaide 5042, South Australia, Australia
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7
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Juthani R, Das A, Doss K, Mandal J. Exploring the use of Congo red agar in improving the serotyping of non-serotypeable Shigella with In-silico evidence. Indian J Med Microbiol 2023; 44:100381. [PMID: 37356833 DOI: 10.1016/j.ijmmb.2023.100381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/27/2022] [Accepted: 04/26/2023] [Indexed: 06/27/2023]
Abstract
OBJECTIVES To assess if congo red could make non-serotypeable Shigella strains serotypeable and to employ molecular docking to determine the basis of the same phenomenon. METHODS We used 42 bacterial strains of non-serotypeable Shigella collected from 2012 to 2019 for this study. Each bacterial strain was freshly inoculated onto congo red agar and incubated at 37° C for 18-24 h. Bacterial colonies obtained were re-subjected to biochemical tests followed by serotyping and serogrouping. In-silico studies to investigate the interaction between MxiC protein of T3SS and O-antigen LPS with congo red were performed. RESULTS Of the total 42 non-serotypeable Shigella studied, (26/42)62% were capable of being serotyped following the use of congo red agar, 65% were Shigella flexneri, 19% were Shigella dysenteriae, while 2 strains (7%) each of Shigella boydii and Shigella sonnei were detected. We observed no change in their biochemical properties. The in-silico molecular docking studies revealed high binding affinity between congo red and the B-Chain of Mxi C. Out of the 5 chains of the O-Antigen, congo red showed robust binding with the B-chain with the involvement of a cluster of hydrophobic interactions between them. This may have a crucial role in the conversion of non-serotypeable strains to serotypeable strains on exposure to congo red as observed in our study. CONCLUSION Congo red agar as a medium converts a sizeable percentage of non-serotypeable Shigella strains to serotypeable Shigella strains.
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Affiliation(s)
- Ronit Juthani
- Jawaharlal Institute of Postgraduate Medical Institute and Research (JIPMER), Puducherry, India.
| | - Ankita Das
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India.
| | - Kamali Doss
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India.
| | - Jharna Mandal
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Institute and Research (JIPMER), Puducherry, India.
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8
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Valeva SV, Degabriel M, Michal F, Gay G, Rohde JR, Randow F, Lagrange B, Henry T. Comparative study of GBP recruitment on two cytosol-dwelling pathogens, Francisella novicida and Shigella flexneri highlights differences in GBP repertoire and in GBP1 motif requirements. Pathog Dis 2023; 81:ftad005. [PMID: 37012222 DOI: 10.1093/femspd/ftad005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023] Open
Abstract
Guanylate-Binding Proteins are interferon-inducible GTPases that play a key role in cell autonomous responses against intracellular pathogens. Despite sharing high sequence similarity, subtle differences among GBPs translate into functional divergences that are still largely not understood. A key GBP feature is the formation of supramolecular GBP complexes on the bacterial surface. Such complexes are observed when GBP1 binds lipopolysaccharide (LPS) from Shigella and Salmonella and further recruits GBP2-4. Here, we compared GBP recruitment on two cytosol-dwelling pathogens, Francisella novicida and S. flexneri. Francisella novicida was coated by GBP1 and GBP2 and to a lower extent by GBP4 in human macrophages. Contrary to S. flexneri, F. novicida was not targeted by GBP3, a feature independent of T6SS effectors. Multiple GBP1 features were required to promote targeting to F. novicida while GBP1 targeting to S. flexneri was much more permissive to GBP1 mutagenesis suggesting that GBP1 has multiple domains that cooperate to recognize F. novicida atypical LPS. Altogether our results indicate that the repertoire of GBPs recruited onto specific bacteria is dictated by GBP-specific features and by specific bacterial factors that remain to be identified.
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Affiliation(s)
- Stanimira V Valeva
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Manon Degabriel
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Fanny Michal
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Gabrielle Gay
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - John R Rohde
- Department of Microbiology and Immunology, Dalhousie University, Halifax, B3H 4R2, NS, Canada
| | - Felix Randow
- Division of Protein and Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, CB2 0QH, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, CB2 0QH, Cambridge, United Kingdom
| | - Brice Lagrange
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Thomas Henry
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
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9
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Roncaioli JL, Babirye JP, Chavez RA, Liu FL, Turcotte EA, Lee AY, Lesser CF, Vance RE. A hierarchy of cell death pathways confers layered resistance to shigellosis in mice. eLife 2023; 12:83639. [PMID: 36645406 PMCID: PMC9876568 DOI: 10.7554/elife.83639] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 01/15/2023] [Indexed: 01/17/2023] Open
Abstract
Bacteria of the genus Shigella cause shigellosis, a severe gastrointestinal disease driven by bacterial colonization of colonic intestinal epithelial cells. Vertebrates have evolved programmed cell death pathways that sense invasive enteric pathogens and eliminate their intracellular niche. Previously we reported that genetic removal of one such pathway, the NAIP-NLRC4 inflammasome, is sufficient to convert mice from resistant to susceptible to oral Shigella flexneri challenge (Mitchell et al., 2020). Here, we investigate the protective role of additional cell death pathways during oral mouse Shigella infection. We find that the Caspase-11 inflammasome, which senses Shigella LPS, restricts Shigella colonization of the intestinal epithelium in the absence of NAIP-NLRC4. However, this protection is limited when Shigella expresses OspC3, an effector that antagonizes Caspase-11 activity. TNFα, a cytokine that activates Caspase-8-dependent apoptosis, also provides potent protection from Shigella colonization of the intestinal epithelium when mice lack both NAIP-NLRC4 and Caspase-11. The combined genetic removal of Caspases-1, -11, and -8 renders mice hyper-susceptible to oral Shigella infection. Our findings uncover a layered hierarchy of cell death pathways that limit the ability of an invasive gastrointestinal pathogen to cause disease.
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Affiliation(s)
- Justin L Roncaioli
- Division of Immunology & Molecular Medicine, Department of Molecular & Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Janet Peace Babirye
- Division of Immunology & Molecular Medicine, Department of Molecular & Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Roberto A Chavez
- Division of Immunology & Molecular Medicine, Department of Molecular & Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Fitty L Liu
- Division of Immunology & Molecular Medicine, Department of Molecular & Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Elizabeth A Turcotte
- Division of Immunology & Molecular Medicine, Department of Molecular & Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Angus Y Lee
- Cancer Research Laboratory, University of California, BerkeleyBerkeleyUnited States
| | - Cammie F Lesser
- Department of Microbiology, Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
- Department of Medicine, Division of Infectious Diseases, Massachusetts General HospitalBostonUnited States
| | - Russell E Vance
- Division of Immunology & Molecular Medicine, Department of Molecular & Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Cancer Research Laboratory, University of California, BerkeleyBerkeleyUnited States
- Immunotherapeutics and Vaccine Research Initiative, University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
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10
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Yin H, Zheng J, He Q, Zhang X, Li X, Ma Y, Liang X, Gao J, Kocsis BL, Li Z, Liu X, Alto NM, Li L, Zhang H. Insights into the GSDMB-mediated cellular lysis and its targeting by IpaH7.8. Nat Commun 2023; 14:61. [PMID: 36599845 PMCID: PMC9813358 DOI: 10.1038/s41467-022-35725-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 12/21/2022] [Indexed: 01/06/2023] Open
Abstract
The multifunctional GSDMB protein is an important molecule in human immunity. The pyroptotic and bactericidal activity of GSDMB is a host response to infection by the bacterial pathogen Shigella flexneri, which employs the virulence effector IpaH7.8 to ubiquitinate and target GSDMB for proteasome-dependent degradation. Furthermore, IpaH7.8 selectively targets human but not mouse GSDMD, suggesting a non-canonical mechanism of substrate selection. Here, we report the crystal structure of GSDMB in complex with IpaH7.8. Together with biochemical and functional studies, we identify the potential membrane engagement sites of GSDMB, revealing general and unique features of gasdermin proteins in membrane recognition. We further illuminate how IpaH7.8 interacts with GSDMB, and delineate the mechanism by which IpaH7.8 ubiquitinates and suppresses GSDMB. Notably, guided by our structural model, we demonstrate that two residues in the α1-α2 loop make the mouse GSDMD invulnerable to IpaH7.8-mediated degradation. These findings provide insights into the versatile functions of GSDMB, which could open new avenues for therapeutic interventions for diseases, including cancers and bacterial infections.
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Affiliation(s)
- Hang Yin
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, 430062, Wuhan, China
| | - Jian Zheng
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
- Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Qiuqiu He
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Xuan Zhang
- Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Xuzichao Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Yongjian Ma
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Xiao Liang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Jiaqi Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China
| | - Benjamin L Kocsis
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Zhuang Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, 430062, Wuhan, China
| | - Xiang Liu
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, 300071, Tianjin, China
| | - Neal M Alto
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Long Li
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China.
- Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China.
| | - Heng Zhang
- The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Haihe Laboratory of Cell Ecosystem, Tianjin Institute of Immunology, Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China.
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, 300070, Tianjin, China.
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Hall CP, Jadeja NB, Sebeck N, Agaisse H. Characterization of MxiE- and H-NS-Dependent Expression of ipaH7.8, ospC1, yccE, and yfdF in Shigella flexneri. mSphere 2022; 7:e0048522. [PMID: 36346241 PMCID: PMC9769918 DOI: 10.1128/msphere.00485-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 10/10/2022] [Indexed: 11/09/2022] Open
Abstract
Shigella flexneri uses a type 3 secretion system (T3SS) apparatus to inject virulence effector proteins into the host cell cytosol. Upon host cell contact, MxiE, an S. flexneri AraC-like transcriptional regulator, is required for the expression of a subset of T3SS effector genes encoded on the large virulence plasmid. Here, we defined the MxiE regulon using RNA-seq. We identified virulence plasmid- and chromosome-encoded genes that are activated in response to type 3 secretion in a MxiE-dependent manner. Bioinformatic analysis revealed that similar to previously known MxiE-dependent genes, chromosome-encoded genes yccE and yfdF contain a regulatory element known as the MxiE box, which is required for their MxiE-dependent expression. The significant AT enrichment of MxiE-dependent genes suggested the involvement of H-NS. Using a dominant negative H-NS system, we demonstrate that H-NS silences the expression of MxiE-dependent genes located on the virulence plasmid (ipaH7.8 and ospC1) and the chromosome (yccE and yfdF). Furthermore, we show that MxiE is no longer required for the expression of ipaH7.8, ospC1, yccE, and yfdF when H-NS silencing is relieved. Finally, we show that the H-NS anti-silencer VirB is not required for ipaH7.8 and yccE expression upon MxiE/IpgC overexpression. Based on these genetic studies, we propose a model of MxiE-dependent gene regulation in which MxiE counteracts H-NS-mediated silencing. IMPORTANCE The expression of horizontally acquired genes, including virulence genes, is subject to complex regulation involving xenogeneic silencing proteins, and counter-silencing mechanisms. The pathogenic properties of Shigella flexneri mainly rely on the acquisition of the type 3 secretion system (T3SS) and cognate effector proteins, whose expression is repressed by the xenogeneic silencing protein H-NS. Based on previous studies, releasing H-NS-mediated silencing mainly relies on two mechanisms involving (i) a temperature shift leading to the release of H-NS at the virF promoter, and (ii) the virulence factor VirB, which dislodges H-NS upon binding to specific motifs upstream of virulence genes, including those encoding the T3SS. In this study, we provide genetic evidence supporting the notion that, in addition to VirB, the AraC family member MxiE also contributes to releasing H-NS-mediated silencing in S. flexneri.
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Affiliation(s)
- Chelsea P. Hall
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Niti B. Jadeja
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Natalie Sebeck
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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12
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Tran Van Nhieu G, Latour-Lambert P, Enninga J. Modification of phosphoinositides by the Shigella effector IpgD during host cell infection. Front Cell Infect Microbiol 2022; 12:1012533. [PMID: 36389142 PMCID: PMC9647168 DOI: 10.3389/fcimb.2022.1012533] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 09/27/2022] [Indexed: 09/15/2023] Open
Abstract
Shigella, the causative agent of bacillary dysentery, subvert cytoskeletal and trafficking processes to invade and replicate in epithelial cells using an arsenal of bacterial effectors translocated through a type III secretion system. Here, we review the various roles of the type III effector IpgD, initially characterized as phosphatidylinositol 4,5 bisphosphate (PI4,5P2) 4-phosphatase. By decreasing PI4,5P2 levels, IpgD triggers the disassembly of cortical actin filaments required for bacterial invasion and cell migration. PI5P produced by IpgD further stimulates signaling pathways regulating cell survival, macropinosome formation, endosomal trafficking and dampening of immune responses. Recently, IpgD was also found to exhibit phosphotransferase activity leading to PI3,4P2 synthesis adding a new flavor to this multipotent bacterial enzyme. The substrate of IpgD, PI4,5P2 is also the main substrate hydrolyzed by endogenous phospholipases C to produce inositoltriphosphate (InsP3), a major Ca2+ second messenger. Hence, beyond the repertoire of effects associated with the direct diversion of phoshoinositides, IpgD indirectly down-regulates InsP3-mediated Ca2+ release by limiting InsP3 production. Furthermore, IpgD controls the intracellular lifestyle of Shigella promoting Rab8/11 -dependent recruitment of the exocyst at macropinosomes to remove damaged vacuolar membrane remnants and promote bacterial cytosolic escape. IpgD thus emerges as a key bacterial effector for the remodeling of host cell membranes.
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Affiliation(s)
- Guy Tran Van Nhieu
- Institute for Integrative Biology of the Cell – Centre National de la Recherche Scientifique (CNRS) UMR9198 - Institut National de la Santé et de la Recherche Médicale (Inserm) U1280, Team Calcium Signaling and Microbial Infections, Gif-sur-Yvette, France
| | - Patricia Latour-Lambert
- Institut Pasteur, Unité Dynamique des interactions hôtes-pathogènes and Centre National de la Recherche Scientifique (CNRS) UMR3691, Université de Paris Cité, Paris, France
| | - Jost Enninga
- Institut Pasteur, Unité Dynamique des interactions hôtes-pathogènes and Centre National de la Recherche Scientifique (CNRS) UMR3691, Université de Paris Cité, Paris, France
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Xerri NL, Payne SM. Bacteroides thetaiotaomicron Outer Membrane Vesicles Modulate Virulence of Shigella flexneri. mBio 2022; 13:e0236022. [PMID: 36102517 PMCID: PMC9600379 DOI: 10.1128/mbio.02360-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 11/20/2022] Open
Abstract
The role of the gut microbiota in the pathogenesis of Shigella flexneri remains largely unknown. To understand the impact of the gut microbiota on S. flexneri virulence, we examined the effect of interspecies interactions with Bacteroides thetaiotaomicron, a prominent member of the gut microbiota, on S. flexneri invasion. When grown in B. thetaiotaomicron-conditioned medium, S. flexneri showed reduced invasion of human epithelial cells. This decrease in invasiveness of S. flexneri resulted from a reduction in the level of the S. flexneri master virulence regulator VirF. Reduction of VirF corresponded with a decrease in expression of a secondary virulence regulator, virB, as well as expression of S. flexneri virulence genes required for invasion, intracellular motility, and spread. Repression of S. flexneri virulence factors by B. thetaiotaomicron-conditioned medium was not caused by either a secreted metabolite or secreted protein but rather was due to the presence of B. thetaiotaomicron outer membrane vesicles (OMVs) in the conditioned medium. The addition of purified B. thetaiotaomicron OMVs to S. flexneri growth medium recapitulated the inhibitory effects of B. thetaiotaomicron-conditioned medium on invasion, virulence gene expression, and virulence protein levels. Total lipids extracted from either B. thetaiotaomicron cells or B. thetaiotaomicron OMVs also recapitulated the effects of B. thetaiotaomicron-conditioned medium on expression of the S. flexneri virulence factor IpaC, indicating that B. thetaiotaomicron OMV lipids, rather than a cargo contained in the vesicles, are the active factor responsible for the inhibition of S. flexneri virulence. IMPORTANCE Shigella flexneri is the causative agent of bacillary dysentery in humans. Shigella spp. are one of the leading causes of diarrheal morbidity and mortality, especially among children in low- and middle-income countries. The rise of antimicrobial resistance combined with the lack of an effective vaccine for Shigella heightens the importance of studies aimed at better understanding previously uncharacterized aspects of Shigella pathogenesis. Here, we show that conditioned growth medium from the commensal bacterium Bacteroides thetaiotaomicron represses the invasion of S. flexneri. This repression is due to the presence of B. thetaiotaomicron outer membrane vesicles. These findings establish a role for interspecies interactions with a prominent member of the gut microbiota in modulating the virulence of S. flexneri and identify a novel function of outer membrane vesicles in interbacterial signaling between members of the gut microbiota and an enteric pathogen.
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Affiliation(s)
- Nicholas L. Xerri
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Shelley M. Payne
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
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14
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Wood TE, Westervelt KA, Yoon JM, Eshleman HD, Levy R, Burnes H, Slade DJ, Lesser CF, Goldberg MB. The Shigella Spp. Type III Effector Protein OspB Is a Cysteine Protease. mBio 2022; 13:e0127022. [PMID: 35638611 PMCID: PMC9239218 DOI: 10.1128/mbio.01270-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/20/2022] Open
Abstract
The type III secretion system is required for virulence of many pathogenic bacteria. Bacterial effector proteins delivered into target host cells by this system modulate host signaling pathways and processes in a manner that promotes infection. Here, we define the activity of the effector protein OspB of the human pathogen Shigella spp., the etiological agent of shigellosis and bacillary dysentery. Using the yeast Saccharomyces cerevisiae as a model organism, we show that OspB sensitizes cells to inhibition of TORC1, the central regulator of growth and metabolism. In silico analyses reveal that OspB bears structural homology to bacterial cysteine proteases that target mammalian cell processes, and we define a conserved cysteine-histidine catalytic dyad required for OspB function. Using yeast genetic screens, we identify a crucial role for the arginine N-degron pathway in the yeast growth inhibition phenotype and show that inositol hexakisphosphate is an OspB cofactor. We find that a yeast substrate for OspB is the TORC1 component Tco89p, proteolytic cleavage of which generates a C-terminal fragment that is targeted for degradation via the arginine N-degron pathway; processing and degradation of Tco89p is required for the OspB phenotype. In all, we demonstrate that the Shigella T3SS effector OspB is a cysteine protease and decipher its interplay with eukaryotic cell processes. IMPORTANCEShigella spp. are important human pathogens and among the leading causes of diarrheal mortality worldwide, especially in children. Virulence depends on the Shigella type III secretion system (T3SS). Definition of the roles of the bacterial effector proteins secreted by the T3SS is key to understanding Shigella pathogenesis. The effector protein OspB contributes to a range of phenotypes during infection, yet the mechanism of action is unknown. Here, we show that S. flexneri OspB possesses cysteine protease activity in both yeast and mammalian cells, and that enzymatic activity of OspB depends on a conserved cysteine-histidine catalytic dyad. We determine how its protease activity sensitizes cells to TORC1 inhibition in yeast, finding that OspB cleaves a component of yeast TORC1, and that the degradation of the C-terminal cleavage product is responsible for OspB-mediated hypersensitivity to TORC1 inhibitors. Thus, OspB is a cysteine protease that depends on a conserved cysteine-histidine catalytic dyad.
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Affiliation(s)
- Thomas E. Wood
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Kathleen A. Westervelt
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Jessica M. Yoon
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Heather D. Eshleman
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Roie Levy
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Henry Burnes
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Daniel J. Slade
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Cammie F. Lesser
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Marcia B. Goldberg
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
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15
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Köseoğlu VK, Jones MK, Agaisse H. The type 3 secretion effector IpgD promotes S. flexneri dissemination. PLoS Pathog 2022; 18:e1010324. [PMID: 35130324 PMCID: PMC8853559 DOI: 10.1371/journal.ppat.1010324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/17/2022] [Accepted: 01/31/2022] [Indexed: 12/15/2022] Open
Abstract
The bacterial pathogen Shigella flexneri causes 270 million cases of bacillary dysentery worldwide every year, resulting in more than 200,000 deaths. S. flexneri pathogenic properties rely on its ability to invade epithelial cells and spread from cell to cell within the colonic epithelium. This dissemination process relies on actin-based motility in the cytosol of infected cells and formation of membrane protrusions that project into adjacent cells and resolve into double-membrane vacuoles (DMVs) from which the pathogen escapes, thereby achieving cell-to-cell spread. S. flexneri dissemination is facilitated by the type 3 secretion system (T3SS) through poorly understood mechanisms. Here, we show that the T3SS effector IpgD facilitates the resolution of membrane protrusions into DMVs during S. flexneri dissemination. The phosphatidylinositol 4-phosphatase activity of IpgD decreases PtdIns(4,5)P2 levels in membrane protrusions, thereby counteracting de novo cortical actin formation in protrusions, a process that restricts the resolution of protrusions into DMVs. Finally, using an infant rabbit model of shigellosis, we show that IpgD is required for efficient cell-to-cell spread in vivo and contributes to the severity of dysentery. The intracellular pathogen Shigella flexneri is the causative agent of bacillary dysentery (blood in stool). Invasion of epithelial cells and cell-to-cell spread are critical determinants of S. flexneri pathogenesis. Cell-to-cell spread relies on the formation of membrane protrusions that project into adjacent cells and resolve into vacuoles. The molecular mechanisms supporting this dissemination process are poorly understood. In this study, we show that S. flexneri employs the phosphatidylinositol phosphatase activity of the T3SS effector protein IpgD to manipulate phosphoinositides in the protrusion membrane. Manipulation of phosphoinositide signaling restricts the formation of actin networks underneath the protrusion membrane, which would otherwise prevent the scission of protrusions into vacuoles. We also demonstrate that IpgD is required for efficient dissemination in the colon of infant rabbits and contributes to the severity of disease. This study exemplifies how manipulation of phosphoinositide signaling by intracellular pathogens supports bacterial pathogenesis.
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Affiliation(s)
- Volkan K. Köseoğlu
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - Marieke K. Jones
- Claude Moore Health Sciences Library, University of Virginia, Charlottesville, Virginia, United States of America
| | - Hervé Agaisse
- Department of Microbiology, Immunology, and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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16
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Nie JJ, Pian YY, Hu JH, Fan GQ, Zeng LT, Ouyang QG, Gao ZX, Liu Z, Wang CC, Liu Q, Cai JP. Increased systemic RNA oxidative damage and diagnostic value of RNA oxidative metabolites during Shigella flexneri-induced intestinal infection. World J Gastroenterol 2021; 27:6248-6261. [PMID: 34712030 PMCID: PMC8515791 DOI: 10.3748/wjg.v27.i37.6248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/29/2021] [Accepted: 08/09/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Shigella flexneri (S. flexneri) is a major pathogen causing acute intestinal infection, but the systematic oxidative damage incurred during the course of infection has not been investigated.
AIM To investigate the incurred systemic RNA oxidative damage and the diagnostic value of RNA oxidative metabolites during S. flexneri-induced intestinal infection.
METHODS In this study, a Sprague-Dawley rat model of acute intestinal infection was established by oral gavage with S. flexneri strains. The changes in white blood cells (WBCs) and cytokine levels in blood and the inflammatory response in the colon were investigated. We also detected the RNA and DNA oxidation in urine and tissues.
RESULTS S. flexneri infection induced an increase in WBCs, C-reactive protein, interleukin (IL)-6, IL-10, IL-1β, IL-4, IL-17a, IL-10, and tumor necrosis factor α (TNF-α) in blood. Of note, a significant increase in urinary 8-oxo-7,8-dihydroguanosine (8-oxo-Gsn), an important marker of total RNA oxidation, was detected after intestinal infection (P = 0.03). The urinary 8-oxo-Gsn level returned to the baseline level after recovery from infection. In addition, the results of a correlation analysis showed that urinary 8-oxo-Gsn was positively correlated with the WBC count and the cytokines IL-6, TNF-α, IL-10, IL-1β, and IL-17α. Further detection of the oxidation in different tissues showed that S. flexneri infection induced RNA oxidative damage in the colon, ileum, liver, spleen, and brain.
CONCLUSION Acute infection induced by S. flexneri causes increased RNA oxidative damage in various tissues (liver, spleen, and brain) and an increase of 8-oxo-Gsn, a urinary metabolite. Urinary 8-oxo-Gsn may be useful as a biomarker for evaluating the severity and prognosis of infection.
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Affiliation(s)
- Jing-Jing Nie
- Department of Microbiology, National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Ya-Ya Pian
- Department of Microbiology, National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Ji-Hong Hu
- Department of Microbiology, National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Guo-Qing Fan
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Beijing Hospital, National Center of Gerontology, National Health Commission, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Lv-Tao Zeng
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Beijing Hospital, National Center of Gerontology, National Health Commission, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Qiu-Geng Ouyang
- Department of Pharmacy, Wenzhou Medical University, Wenzhou 325035, Zhejiang Province, China
| | - Zhen-Xiang Gao
- Department of Microbiology, National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Zhen Liu
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Beijing Hospital, National Center of Gerontology, National Health Commission, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Chen-Chen Wang
- Department of Pharmacy, Wenzhou Medical University, Wenzhou 325035, Zhejiang Province, China
| | - Qian Liu
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Beijing Hospital, National Center of Gerontology, National Health Commission, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Jian-Ping Cai
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Beijing Hospital, National Center of Gerontology, National Health Commission, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing 100730, China
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Maculins T, Verschueren E, Hinkle T, Choi M, Chang P, Chalouni C, Rao S, Kwon Y, Lim J, Katakam AK, Kunz RC, Erickson BK, Huang T, Tsai TH, Vitek O, Reichelt M, Senbabaoglu Y, Mckenzie B, Rohde JR, Dikic I, Kirkpatrick DS, Murthy A. Multiplexed proteomics of autophagy-deficient murine macrophages reveals enhanced antimicrobial immunity via the oxidative stress response. eLife 2021; 10:e62320. [PMID: 34085925 PMCID: PMC8177894 DOI: 10.7554/elife.62320] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 05/12/2021] [Indexed: 12/11/2022] Open
Abstract
Defective autophagy is strongly associated with chronic inflammation. Loss-of-function of the core autophagy gene Atg16l1 increases risk for Crohn's disease in part by enhancing innate immunity through myeloid cells such as macrophages. However, autophagy is also recognized as a mechanism for clearance of certain intracellular pathogens. These divergent observations prompted a re-evaluation of ATG16L1 in innate antimicrobial immunity. In this study, we found that loss of Atg16l1 in myeloid cells enhanced the killing of virulent Shigella flexneri (S.flexneri), a clinically relevant enteric bacterium that resides within the cytosol by escaping from membrane-bound compartments. Quantitative multiplexed proteomics of murine bone marrow-derived macrophages revealed that ATG16L1 deficiency significantly upregulated proteins involved in the glutathione-mediated antioxidant response to compensate for elevated oxidative stress, which simultaneously promoted S.flexneri killing. Consistent with this, myeloid-specific deletion of Atg16l1 in mice accelerated bacterial clearance in vitro and in vivo. Pharmacological induction of oxidative stress through suppression of cysteine import enhanced microbial clearance by macrophages. Conversely, antioxidant treatment of macrophages permitted S.flexneri proliferation. These findings demonstrate that control of oxidative stress by ATG16L1 and autophagy regulates antimicrobial immunity against intracellular pathogens.
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Affiliation(s)
- Timurs Maculins
- Department of Cancer Immunology, GenentechSouth San FranciscoUnited States
- Institute of Biochemistry II, Goethe UniversityFrankfurt am MainGermany
| | - Erik Verschueren
- Department of Microchemistry, Proteomics and Lipidomics, GenentechSouth San FranciscoUnited States
| | - Trent Hinkle
- Department of Microchemistry, Proteomics and Lipidomics, GenentechSouth San FranciscoUnited States
| | - Meena Choi
- Department of Microchemistry, Proteomics and Lipidomics, GenentechSouth San FranciscoUnited States
- Khoury College of Computer Sciences, Northeastern UniversityBostonUnited States
| | - Patrick Chang
- Department of Pathology, GenentechSouth San FranciscoUnited States
| | - Cecile Chalouni
- Department of Pathology, GenentechSouth San FranciscoUnited States
| | - Shilpa Rao
- Department of Oncology Bioinformatics, GenentechSouth San FranciscoUnited States
| | - Youngsu Kwon
- Department of Translational Immunology, GenentechSouth San FranciscoUnited States
| | - Junghyun Lim
- Department of Cancer Immunology, GenentechSouth San FranciscoUnited States
| | | | | | | | - Ting Huang
- Khoury College of Computer Sciences, Northeastern UniversityBostonUnited States
| | - Tsung-Heng Tsai
- Khoury College of Computer Sciences, Northeastern UniversityBostonUnited States
- Department of Mathematical Sciences, Kent State UniversityKentUnited States
| | - Olga Vitek
- Khoury College of Computer Sciences, Northeastern UniversityBostonUnited States
| | - Mike Reichelt
- Department of Pathology, GenentechSouth San FranciscoUnited States
| | - Yasin Senbabaoglu
- Department of Oncology Bioinformatics, GenentechSouth San FranciscoUnited States
| | - Brent Mckenzie
- Department of Translational Immunology, GenentechSouth San FranciscoUnited States
| | - John R Rohde
- Department of Microbiology and Immunology, Dalhousie UniversityHalifaxCanada
| | - Ivan Dikic
- Institute of Biochemistry II, Goethe UniversityFrankfurt am MainGermany
- Department of Infectious Diseases, GenentechSouth San FranciscoUnited States
| | | | - Aditya Murthy
- Interline TherapeuticsSouth San FranciscoUnited States
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Wimmi S, Balinovic A, Jeckel H, Selinger L, Lampaki D, Eisemann E, Meuskens I, Linke D, Drescher K, Endesfelder U, Diepold A. Dynamic relocalization of cytosolic type III secretion system components prevents premature protein secretion at low external pH. Nat Commun 2021; 12:1625. [PMID: 33712575 PMCID: PMC7954860 DOI: 10.1038/s41467-021-21863-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 02/12/2021] [Indexed: 01/31/2023] Open
Abstract
Many bacterial pathogens use a type III secretion system (T3SS) to manipulate host cells. Protein secretion by the T3SS injectisome is activated upon contact to any host cell, and it has been unclear how premature secretion is prevented during infection. Here we report that in the gastrointestinal pathogens Yersinia enterocolitica and Shigella flexneri, cytosolic injectisome components are temporarily released from the proximal interface of the injectisome at low external pH, preventing protein secretion in acidic environments, such as the stomach. We show that in Yersinia enterocolitica, low external pH is detected in the periplasm and leads to a partial dissociation of the inner membrane injectisome component SctD, which in turn causes the dissociation of the cytosolic T3SS components. This effect is reversed upon restoration of neutral pH, allowing a fast activation of the T3SS at the native target regions within the host. These findings indicate that the cytosolic components form an adaptive regulatory interface, which regulates T3SS activity in response to environmental conditions.
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Affiliation(s)
- Stephan Wimmi
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Alexander Balinovic
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Mellon College of Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Hannah Jeckel
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Marburg, Germany
| | - Lisa Selinger
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Dimitrios Lampaki
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Max-Planck-Institut für Immunbiologie und Epigenetik, Freiburg, Germany
| | - Emma Eisemann
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- James Madison University, Harrisonburg, VA, USA
| | - Ina Meuskens
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Marburg, Germany
| | - Ulrike Endesfelder
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Department of Physics, Mellon College of Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.
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19
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Singh R, Hano C, Nath G, Sharma B. Green Biosynthesis of Silver Nanoparticles Using Leaf Extract of Carissa carandas L. and Their Antioxidant and Antimicrobial Activity against Human Pathogenic Bacteria. Biomolecules 2021; 11:299. [PMID: 33671333 PMCID: PMC7922588 DOI: 10.3390/biom11020299] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 12/21/2022] Open
Abstract
Carissa carandas L. is traditionally used as antibacterial medicine and accumulates many antioxidant phytochemicals. Here, we expand this traditional usage with the green biosynthesis of silver nanoparticles (AgNPs) achieved using a Carissa carandas L. leaf extract as a reducing and capping agent. The green synthesis of AgNPs reaction was carried out using 1mM silver nitrate and leaf extract. The effect of temperature on the synthesis of AgNPs was examined using room temperature (25 °C) and 60 °C. The silver nanoparticles were formed in one hour by stirring at room temperature. In this case, a yellowish brown colour was developed. The successful formation of silver nanoparticles was confirmed by UV-Vis, Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analysis. The characteristic peaks of the UV-vis spectrum and XRD confirmed the synthesis of AgNPs. The biosynthesised AgNPs showed potential antioxidant activity through DPPH assay. These AgNPs also exhibited potential antibacterial activity against human pathogenic bacteria. The results were compared with the antioxidant and antibacterial activities of the plant extract, and clearly suggest that the green biosynthesized AgNPs can constitute an effective antioxidant and antibacterial agent.
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Affiliation(s)
- Reetika Singh
- Department of Biochemistry, University of Allahabad, Allahabad 211002, India
| | - Christophe Hano
- Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), INRA USC1328, Université d’Orléans, Eure et Loir Campus, 21 rue de Loigny la Bataille, F-28000 Chartres, France
- Bioactifs et Cosmétiques, Centre National de la Recherche Scientifique (CNRS)—Groupement de Recherche 3711, Université d’Orléans, 45067 Orléans CEDEX 2, France
| | - Gopal Nath
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India;
| | - Bechan Sharma
- Department of Biochemistry, University of Allahabad, Allahabad 211002, India
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20
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Yang G, Li B, Jia L, Qiu H, Yang M, Zhu B, Xie J, Qiu S, Li P, Ma H, Song H, Wang L. A Novel sRNA in Shigella flexneri That Regulates Tolerance and Virulence Under Hyperosmotic Pressure. Front Cell Infect Microbiol 2020; 10:483. [PMID: 33042862 PMCID: PMC7526569 DOI: 10.3389/fcimb.2020.00483] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 08/04/2020] [Indexed: 01/09/2023] Open
Abstract
Regulation of the environmental stress response and virulence of Shigella flexneri may involve multiple signaling pathways; however, these mechanisms are not well-defined. In bacteria, small regulatory RNAs (sRNAs) regulate bacterial growth, metabolism, virulence, and environmental stress response. Therefore, identifying novel functional sRNAs in S. flexneri could help elucidate pathogenic adaptations to host micro-environmental stresses and associated virulence. The aim of this study was to confirm the presence of an sRNA, Ssr54, in S. flexneri and to determine its functions and possible mechanism of action. Ssr54 was found to regulate tolerance and virulence under hyperosmotic pressure. Its expression was verified by qRT-PCR and Northern blotting, and its genomic position was confirmed by 5'-rapid amplification of cDNA ends. Ssr54 expression was significantly decreased (~ 80%) under hyperosmotic conditions (680 mM NaCl), and the survival rate of the Ssr54 deletion strain increased by 20% under these conditions. This suggested that Ssr54 has been selected to promote host survival under hyperosmotic conditions. Additionally, virulence assessment, including guinea pig Sereny test and competitive invasion assays in mouse lungs, revealed that Ssr54 deletion significantly decreased S. flexneri virulence. Two-dimensional gel analyses suggest that Ssr54 may modulate the expression of tolC, ompA, and treF genes, which may affect the virulence and survival of S. flexneri under osmotic pressures. Furthermore, treF expression has been shown to improve the survival of S. flexneri under osmotic pressures. These results suggest that Ssr54 has a broad range of action in S. flexneri response to hyperosmotic environmental stresses and in controlling its virulence to adapt to environmental stresses encountered during host infection.
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Affiliation(s)
- Guang Yang
- Center for Disease Control and Prevention of Chinese People's Liberation Army, Beijing, China
- The 5th Medical Center of General Hospital of Chinese People's Liberation Army, Beijing, China
| | - Boan Li
- The 5th Medical Center of General Hospital of Chinese People's Liberation Army, Beijing, China
| | - Leili Jia
- Center for Disease Control and Prevention of Chinese People's Liberation Army, Beijing, China
| | - Huaiyu Qiu
- Department of Ophthalmology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Mingjuan Yang
- Center for Disease Control and Prevention of Chinese People's Liberation Army, Beijing, China
| | | | - Jing Xie
- Center for Disease Control and Prevention of Chinese People's Liberation Army, Beijing, China
| | - Shaofu Qiu
- Center for Disease Control and Prevention of Chinese People's Liberation Army, Beijing, China
| | - Peng Li
- Center for Disease Control and Prevention of Chinese People's Liberation Army, Beijing, China
| | - Hui Ma
- The 6th Medical Center of General Hospital of Chinese People's Liberation Army, Beijing, China
| | - Hongbin Song
- Center for Disease Control and Prevention of Chinese People's Liberation Army, Beijing, China
| | - Ligui Wang
- Center for Disease Control and Prevention of Chinese People's Liberation Army, Beijing, China
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21
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Chang YY, Stévenin V, Duchateau M, Giai Gianetto Q, Hourdel V, Rodrigues CD, Matondo M, Reiling N, Enninga J. Shigella hijacks the exocyst to cluster macropinosomes for efficient vacuolar escape. PLoS Pathog 2020; 16:e1008822. [PMID: 32866204 PMCID: PMC7485983 DOI: 10.1371/journal.ppat.1008822] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 09/11/2020] [Accepted: 07/20/2020] [Indexed: 12/15/2022] Open
Abstract
Shigella flexneri invades host cells by entering within a bacteria-containing vacuole (BCV). In order to establish its niche in the host cytosol, the bacterium ruptures its BCV. Contacts between S. flexneri BCV and infection-associated macropinosomes (IAMs) formed in situ have been reported to enhance BCV disintegration. The mechanism underlying S. flexneri vacuolar escape remains however obscure. To decipher the molecular mechanism priming the communication between the IAMs and S. flexneri BCV, we performed mass spectrometry-based analysis of the magnetically purified IAMs from S. flexneri-infected cells. While proteins involved in host recycling and exocytic pathways were significantly enriched at the IAMs, we demonstrate more precisely that the S. flexneri type III effector protein IpgD mediates the recruitment of the exocyst to the IAMs through the Rab8/Rab11 pathway. This recruitment results in IAM clustering around S. flexneri BCV. More importantly, we reveal that IAM clustering subsequently facilitates an IAM-mediated unwrapping of the ruptured vacuole membranes from S. flexneri, enabling the naked bacterium to be ready for intercellular spread via actin-based motility. Taken together, our work untangles the molecular cascade of S. flexneri-driven host trafficking subversion at IAMs to develop its cytosolic lifestyle, a crucial step en route for infection progression at cellular and tissue level.
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Affiliation(s)
- Yuen-Yan Chang
- Dynamics of Host-Pathogen Interactions Unit and CNRS UMR3691, Institut Pasteur, Paris, France
| | - Virginie Stévenin
- Dynamics of Host-Pathogen Interactions Unit and CNRS UMR3691, Institut Pasteur, Paris, France
| | - Magalie Duchateau
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS, Paris, France
| | - Quentin Giai Gianetto
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS, Paris, France
- Hub Bioinformatics et Biostatistics, Computational Biology Department, USR CNRS, Institut Pasteur, Paris, France
| | - Veronique Hourdel
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS, Paris, France
| | - Cristina Dias Rodrigues
- Dynamics of Host-Pathogen Interactions Unit and CNRS UMR3691, Institut Pasteur, Paris, France
| | - Mariette Matondo
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS, Paris, France
| | - Norbert Reiling
- Microbial Interface Biology, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
- German Center for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel, Borstel, Germany
| | - Jost Enninga
- Dynamics of Host-Pathogen Interactions Unit and CNRS UMR3691, Institut Pasteur, Paris, France
- * E-mail:
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22
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Russo BC, Duncan JK, Wiscovitch AL, Hachey AC, Goldberg MB. Activation of Shigella flexneri type 3 secretion requires a host-induced conformational change to the translocon pore. PLoS Pathog 2019; 15:e1007928. [PMID: 31725799 PMCID: PMC6879154 DOI: 10.1371/journal.ppat.1007928] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 11/26/2019] [Accepted: 09/30/2019] [Indexed: 12/17/2022] Open
Abstract
Type 3 secretion systems (T3SSs) are conserved bacterial nanomachines that inject virulence proteins (effectors) into eukaryotic cells during infection. Due to their ability to inject heterologous proteins into human cells, these systems are being developed as therapeutic delivery devices. The T3SS assembles a translocon pore in the plasma membrane and then docks onto the pore. Docking activates effector secretion through the pore and into the host cytosol. Here, using Shigella flexneri, a model pathogen for the study of type 3 secretion, we determined the molecular mechanisms by which host intermediate filaments trigger docking and enable effector secretion. We show that the interaction of intermediate filaments with the translocon pore protein IpaC changed the pore's conformation in a manner that was required for docking. Intermediate filaments repositioned residues of the Shigella pore protein IpaC that are located on the surface of the pore and in the pore channel. Restricting these conformational changes blocked docking in an intermediate filament-dependent manner. These data demonstrate that a host-induced conformational change to the pore enables T3SS docking and effector secretion, providing new mechanistic insight into the regulation of type 3 secretion.
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Affiliation(s)
- Brian C. Russo
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jeffrey K. Duncan
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Alexandra L. Wiscovitch
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Research Scholar Initiative, The Graduate School of Arts and Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Austin C. Hachey
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Marcia B. Goldberg
- Center for Bacterial Pathogenesis, Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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23
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Pizarro-Cerda J, Tran Van Nhieu G. Philippe Sansonetti and Cellular Microbiology. Cell Microbiol 2019; 21:e13134. [PMID: 31664785 DOI: 10.1111/cmi.13134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Fogolari M, Mavian C, Angeletti S, Salemi M, Lampel KA, Maurelli AT. Distribution and characterization of Shiga toxin converting temperate phages carried by Shigella flexneri in Hispaniola. Infect Genet Evol 2018; 65:321-328. [PMID: 30075254 PMCID: PMC6260934 DOI: 10.1016/j.meegid.2018.07.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/22/2018] [Accepted: 07/29/2018] [Indexed: 01/29/2023]
Abstract
Shigella infections account for a considerable burden of acute diarrheal diseases worldwide and remain a major cause of childhood mortality in developing countries. Although, all four species of Shigella (S. dysenteriae, S. flexneri, S. boydii, and S. sonnei) cause bacillary dysentery, historically only S. dysenteriae type 1 has been recognized as carrying the genes for Shiga toxin (stx). Recent epidemiological data, however, have suggested that the emergence of stx carrying S. flexneri strains may have originated from bacteriophage-mediated inter-species horizontal gene transfer in one specific geographical area, Hispaniola. To test this hypothesis, we analyzed whole genome sequences of stx-encoding phages carried by S. flexneri strains isolated in Haiti and S. flexneri S. boydii and S. dysenteriae strains isolated from international travelers who likely acquired the infection in Haiti or the Dominican Republic. Phylogenetic analysis showed that phage sequences encoded in the Shigella strains from Hispaniola were bacteriophage φPOC-J13 and they were all closely related to a phage isolated from a USA isolate, E. coli 2009C-3133 serotype O119:H4. In addition, despite the low genetic heterogeneity of phages from different Shigella spp. circulating in the Caribbean island between 2001 and 2014, two distinct clusters emerged in Haiti and the Dominican Republic. Each cluster possibly originated from phages isolated from S. flexneri 2a, and within each cluster several instances of horizontal phage transfer from S. flexneri 2a to other species were detected. The implications of the emergence of stx-producing non-S. dysenteriae type 1 Shigella species, such as S. flexneri, spans not only the basic science behind horizontal phage spread, but also extends to medical treatment of patients infected with this pathogen.
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Affiliation(s)
- Marta Fogolari
- Unit of Clinical Laboratory Science, University Campus Bio-Medico of Rome, Rome, Italy; Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Carla Mavian
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA; Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL, USA
| | - Silvia Angeletti
- Unit of Clinical Laboratory Science, University Campus Bio-Medico of Rome, Rome, Italy
| | - Marco Salemi
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA; Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL, USA.
| | | | - Anthony T Maurelli
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA; Department of Environmental and Global Health, University of Florida, Gainesville, FL, USA.
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25
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Liu W, Zhou Y, Peng T, Zhou P, Ding X, Li Z, Zhong H, Xu Y, Chen S, Hang HC, Shao F. N ε-fatty acylation of multiple membrane-associated proteins by Shigella IcsB effector to modulate host function. Nat Microbiol 2018; 3:996-1009. [PMID: 30061757 PMCID: PMC6466622 DOI: 10.1038/s41564-018-0215-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 06/27/2018] [Indexed: 11/09/2022]
Abstract
Shigella flexneri, an intracellular Gram-negative bacterium causative for shigellosis, employs a type III secretion system to deliver virulence effectors into host cells. One such effector, IcsB, is critical for S. flexneri intracellular survival and pathogenesis, but its mechanism of action is unknown. Here, we discover that IcsB is an 18-carbon fatty acyltransferase catalysing lysine Nε-fatty acylation. IcsB disrupted the actin cytoskeleton in eukaryotes, resulting from Nε-fatty acylation of RhoGTPases on lysine residues in their polybasic region. Chemical proteomic profiling identified about 60 additional targets modified by IcsB during infection, which were validated by biochemical assays. Most IcsB targets are membrane-associated proteins bearing a lysine-rich polybasic region, including members of the Ras, Rho and Rab families of small GTPases. IcsB also modifies SNARE proteins and other non-GTPase substrates, suggesting an extensive interplay between S. flexneri and host membrane trafficking. IcsB is localized on the Shigella-containing vacuole to fatty-acylate its targets. Knockout of CHMP5-one of the IcsB targets and a component of the ESCRT-III complex-specifically affected S. flexneri escape from host autophagy. The unique Nε-fatty acyltransferase activity of IcsB and its altering of the fatty acylation landscape of host membrane proteomes represent an unprecedented mechanism in bacterial pathogenesis.
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Affiliation(s)
- Wang Liu
- College of Life Science, Peking University, Beijing, China
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, National Institute of Biological Sciences, Beijing, China
- National Institute of Biological Sciences, Beijing, China
| | - Yan Zhou
- National Institute of Biological Sciences, Beijing, China
- College of Life Sciences, Beijing Normal University, Beijing, China
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tao Peng
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA
| | - Ping Zhou
- National Institute of Biological Sciences, Beijing, China
| | - Xiaojun Ding
- National Institute of Biological Sciences, Beijing, China
| | - Zilin Li
- National Institute of Biological Sciences, Beijing, China
| | - Haoyu Zhong
- National Institute of Biological Sciences, Beijing, China
| | - Yue Xu
- National Institute of Biological Sciences, Beijing, China
| | - She Chen
- National Institute of Biological Sciences, Beijing, China
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA.
| | - Feng Shao
- National Institute of Biological Sciences, Beijing, China.
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
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26
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Kunstmann S, Scheidt T, Buchwald S, Helm A, Mulard LA, Fruth A, Barbirz S. Bacteriophage Sf6 Tailspike Protein for Detection of Shigella flexneri Pathogens. Viruses 2018; 10:E431. [PMID: 30111705 PMCID: PMC6116271 DOI: 10.3390/v10080431] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/26/2018] [Accepted: 08/09/2018] [Indexed: 12/30/2022] Open
Abstract
Bacteriophage research is gaining more importance due to increasing antibiotic resistance. However, for treatment with bacteriophages, diagnostics have to be improved. Bacteriophages carry adhesion proteins, which bind to the bacterial cell surface, for example tailspike proteins (TSP) for specific recognition of bacterial O-antigen polysaccharide. TSP are highly stable proteins and thus might be suitable components for the integration into diagnostic tools. We used the TSP of bacteriophage Sf6 to establish two applications for detecting Shigella flexneri (S. flexneri), a highly contagious pathogen causing dysentery. We found that Sf6TSP not only bound O-antigen of S. flexneri serotype Y, but also the glucosylated O-antigen of serotype 2a. Moreover, mass spectrometry glycan analyses showed that Sf6TSP tolerated various O-acetyl modifications on these O-antigens. We established a microtiter plate-based ELISA like tailspike adsorption assay (ELITA) using a Strep-tag®II modified Sf6TSP. As sensitive screening alternative we produced a fluorescently labeled Sf6TSP via coupling to an environment sensitive dye. Binding of this probe to the S. flexneri O-antigen Y elicited a fluorescence intensity increase of 80% with an emission maximum in the visible light range. The Sf6TSP probes thus offer a promising route to a highly specific and sensitive bacteriophage TSP-based Shigella detection system.
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Affiliation(s)
- Sonja Kunstmann
- Physical Biochemistry, University of Potsdam, 14476 Potsdam, Germany.
| | - Tom Scheidt
- Physical Biochemistry, University of Potsdam, 14476 Potsdam, Germany.
| | - Saskia Buchwald
- Physical Biochemistry, University of Potsdam, 14476 Potsdam, Germany.
| | - Alexandra Helm
- Physical Biochemistry, University of Potsdam, 14476 Potsdam, Germany.
| | - Laurence A Mulard
- Institut Pasteur, Unité de Chimie des Biomolécules, 28 rue du Roux, 75015 Paris, France.
- CNRS UMR 3523, Institut Pasteur, 75015 Paris, France.
| | - Angelika Fruth
- National Reference Centre for Salmonella and other Bacterial Enterics, Robert Koch Institute, 38855 Wernigerode, Germany.
| | - Stefanie Barbirz
- Physical Biochemistry, University of Potsdam, 14476 Potsdam, Germany.
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27
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Bernard AR, Jessop TC, Kumar P, Dickenson NE. Deoxycholate-Enhanced Shigella Virulence Is Regulated by a Rare π-Helix in the Type Three Secretion System Tip Protein IpaD. Biochemistry 2017; 56:6503-6514. [PMID: 29134812 PMCID: PMC5761661 DOI: 10.1021/acs.biochem.7b00836] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Type three secretion systems (T3SS) are specialized nanomachines that support infection by injecting bacterial proteins directly into host cells. The Shigella T3SS has uniquely evolved to sense environmental levels of the bile salt deoxycholate (DOC) and upregulate virulence in response to DOC. In this study, we describe a rare i + 5 hydrogen bonding secondary structure element (π-helix) within the type three secretion system tip protein IpaD that plays a critical role in DOC-enhanced virulence. Specifically, engineered mutations within the π-helix altered the pathogen's response to DOC, with one mutant construct in particular exhibiting an unprecedented reduction in virulence following DOC exposure. Fluorescence polarization binding assays showed that these altered DOC responses are not the result of differences in affinity between IpaD and DOC, but rather differences in the DOC-dependent T3SS tip maturation resulting from binding of IpaD to translocator/effector protein IpaB. Together, these findings begin to uncover the complex mechanism of DOC-enhanced Shigella virulence while identifying an uncommon structural element that may provide a much needed target for non-antibiotic treatment of Shigella infection.
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Affiliation(s)
- Abram R. Bernard
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA
| | - T. Carson Jessop
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA
| | - Prashant Kumar
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047, USA
| | - Nicholas E. Dickenson
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA
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28
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Pinaud L, Ferrari ML, Friedman R, Jehmlich N, von Bergen M, Phalipon A, Sansonetti PJ, Campbell-Valois FX. Identification of novel substrates of Shigella T3SA through analysis of its virulence plasmid-encoded secretome. PLoS One 2017; 12:e0186920. [PMID: 29073283 PMCID: PMC5658099 DOI: 10.1371/journal.pone.0186920] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/10/2017] [Indexed: 11/19/2022] Open
Abstract
Many human Gram-negative bacterial pathogens express a Type Three Secretion Apparatus (T3SA), including among the most notorious Shigella spp., Salmonella enterica, Yersinia enterocolitica and enteropathogenic Escherichia coli (EPEC). These bacteria express on their surface multiple copies of the T3SA that mediate the delivery into host cells of specific protein substrates critical to pathogenesis. Shigella spp. are Gram-negative bacterial pathogens responsible for human bacillary dysentery. The effector function of several Shigella T3SA substrates has largely been studied but their potential cellular targets are far from having been comprehensively delineated. In addition, it is likely that some T3SA substrates have escaped scrutiny as yet. Indeed, sequencing of the virulence plasmid of Shigella flexneri has revealed numerous open reading frames with unknown functions that could encode additional T3SA substrates. Taking advantage of label-free mass spectrometry detection of proteins secreted by a constitutively secreting strain of S. flexneri, we identified five novel substrates of the T3SA. We further confirmed their secretion through the T3SA and translocation into host cells using β-lactamase assays. The coding sequences of two of these novel T3SA substrates (Orf13 and Orf131a) have a guanine-cytosine content comparable to those of T3SA components and effectors. The three other T3SA substrates identified (Orf48, Orf86 and Orf176) have significant homology with antitoxin moieties of type II Toxin-Antitoxin systems usually implicated in the maintenance of low copy plasmids. While Orf13 and Orf131a might constitute new virulence effectors contributing to S. flexneri pathogenicity, potential roles for the translocation into host cells of antitoxins or antitoxin-like proteins during Shigella infection are discussed.
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Affiliation(s)
- Laurie Pinaud
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
| | - Mariana L. Ferrari
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
| | - Robin Friedman
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
- Laboratoire de Biologie Systémique & Centre de Bioinformatique, Biostatistique et Biologie Intégrative, Institut Pasteur, Paris, France
| | - Nico Jehmlich
- Department of Molecular Systems Biology, Helmholtz-Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz-Centre for Environmental Research-UFZ, Leipzig, Germany
- Institute of Biochemistry, University of Leipzig, Faculty of Biosciences, Pharmacy and Psychology, Leipzig, Germany
| | - Armelle Phalipon
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
| | - Philippe J. Sansonetti
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris, France
- U1202, INSERM, Paris, France
- Chaire de Microbiologie et Maladies Infectieuses, Collège de France, Paris, France
| | - François-Xavier Campbell-Valois
- Department of Chemistry and Biomolecular Sciences, Centre for Chemical and Synthetic Biology, Faculty of Science, University of Ottawa, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
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Mauricio RPM, Jeffries CM, Svergun DI, Deane JE. The Shigella Virulence Factor IcsA Relieves N-WASP Autoinhibition by Displacing the Verprolin Homology/Cofilin/Acidic (VCA) Domain. J Biol Chem 2017; 292:134-145. [PMID: 27881679 PMCID: PMC5217673 DOI: 10.1074/jbc.m116.758003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/09/2016] [Indexed: 11/10/2022] Open
Abstract
Shigella flexneri is a bacterial pathogen that invades cells of the gastrointestinal tract, causing severe dysentery. Shigella mediates intracellular motility and spreading via actin comet tail formation. This process is dependent on the surface-exposed, membrane-embedded virulence factor IcsA, which recruits the host actin regulator N-WASP. Although it is clear that Shigella requires N-WASP for this process, the molecular details of this interaction and the mechanism of N-WASP activation remain poorly understood. Here, we show that co-expression of full-length IcsA and the Shigella membrane protease IcsP yields highly pure IcsA passenger domain (residues 53-758). We show that IcsA is monomeric and describe the solution structure of the passenger domain obtained by small-angle X-ray scattering (SAXS) analysis. The SAXS-derived models suggest that IcsA has an elongated shape but, unlike most other autotransporter proteins, possesses a central kink revealing a distinctly curved structure. Pull-down experiments show direct binding of the IcsA passenger domain to both the WASP homology 1 (WH1) domain and the GTPase binding domain (GBD) of N-WASP and no binding to the verprolin homology/cofilin/acidic (VCA) region. Using fluorescence polarization experiments, we demonstrate that IcsA binding to the GBD region displaces the VCA peptide and that this effect is synergistically enhanced upon IcsA binding to the WH1 region. Additionally, domain mapping of the IcsA interaction interface reveals that different regions of IcsA bind to the WH1 and GBD domains of N-WASP. Taken together, our data support a model where IcsA and N-WASP form a tight complex releasing the N-WASP VCA domain to recruit the host cell machinery for actin tail formation.
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Affiliation(s)
- Rui P M Mauricio
- From the Cambridge Institute for Medical Research, Department of Pathology, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom and
| | - Cy M Jeffries
- the European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o DESY, Hamburg 22067, Germany
| | - Dmitri I Svergun
- the European Molecular Biology Laboratory (EMBL), Hamburg Outstation, c/o DESY, Hamburg 22067, Germany
| | - Janet E Deane
- From the Cambridge Institute for Medical Research, Department of Pathology, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, United Kingdom and
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Shen DK, Blocker AJ. MxiA, MxiC and IpaD Regulate Substrate Selection and Secretion Mode in the T3SS of Shigella flexneri. PLoS One 2016; 11:e0155141. [PMID: 27171191 PMCID: PMC4865121 DOI: 10.1371/journal.pone.0155141] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 04/25/2016] [Indexed: 11/19/2022] Open
Abstract
Type III secretion systems (T3SSs) are central virulence devices for many Gram-negative bacterial pathogens of humans, animals & plants. Upon physical contact with eukaryotic host cells, they translocate virulence-mediating proteins, known as effectors, into them during infection. T3SSs are gated from the outside by host-cell contact and from the inside via two cytoplasmic negative regulators, MxiC and IpaD in Shigella flexneri, which together control the effector secretion hierarchy. Their absence leads to premature and increased secretion of effectors. Here, we investigated where and how these regulators act. We demonstrate that the T3SS inner membrane export apparatus protein MxiA plays a role in substrate selection. Indeed, using a genetic screen, we identified two amino acids located on the surface of MxiA's cytoplasmic region (MxiAC) which, when mutated, upregulate late effector expression and, in the case of MxiAI674V, also secretion. The cytoplasmic region of MxiA, but not MxiAN373D and MxiAI674V, interacts directly with the C-terminus of MxiC in a two-hybrid assay. Efficient T3S requires a cytoplasmic ATPase and the proton motive force (PMF), which is composed of the ΔΨ and the ΔpH. MxiA family proteins and their regulators are implicated in utilization of the PMF for protein export. However, our MxiA point mutants show similar PMF utilisation to wild-type, requiring primarily the ΔΨ. On the other hand, lack of MxiC or IpaD, renders the faster T3S seen increasingly dependent on the ΔpH. Therefore, MxiA, MxiC and IpaD act together to regulate substrate selection and secretion mode in the T3SS of Shigella flexneri.
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Affiliation(s)
- Da-Kang Shen
- School of Cellular & Molecular Medicine, Faculty of Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Ariel J. Blocker
- Schools of Cellular & Molecular Medicine and Biochemistry, Faculty of Biomedical Sciences, University of Bristol, Bristol, United Kingdom
- * E-mail:
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Papadopoulos M, Tran ENH, Murray GL, Morona R. Conserved transmembrane glycine residues in the Shigella flexneri polysaccharide co-polymerase protein WzzB influence protein-protein interactions. Microbiology (Reading) 2016; 162:921-929. [PMID: 27028755 DOI: 10.1099/mic.0.000282] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The O antigen (Oag) component of lipopolysaccharides (LPS) is crucial for virulence and Oag chain-length regulation is controlled by the polysaccharide co-polymerase class 1 (PCP1) proteins. Crystal structure analyses indicate that structural conservation among PCP1 proteins is highly maintained, however the mechanism of Oag modal-chain-length control remains to be fully elucidated. Shigella flexneri PCP1 protein WzzBSF confers a modal-chain length of 10-17 Oag repeat units (RUs), whereas the Salmonella enterica Typhimurium PCP1 protein WzzBST confers a modal-chain length of ~16-28 Oag RUs. Both proteins share >70 % overall sequence identity and contain two transmembrane (TM1 and TM2) regions, whereby a conserved proline-glycine-rich motif overlapping the TM2 region is identical in both proteins. Conserved glycine residues within TM2 are functionally important, as glycine to alanine substitutions at positions 305 and 311 confer very short Oag modal-chain length (~2-6 Oag RUs). In this study, WzzBSF was co-expressed with WzzBST in S. flexneri and a single intermediate modal-chain length of ~11-21 Oag RUs was observed, suggesting the presence of Wzz:Wzz interactions. Interestingly, co-expression of WzzBSF with WzzBG305A/G311A conferred a bimodal LPS Oag chain length (despite over 99 % protein sequence identity), and we hypothesized that the proteins fail to interact. Co-purification assays detected His6-WzzBSF co-purifying with FLAG-tagged WzzBST but not with FLAG-tagged WzzBG305A/G311A, supporting our hypothesis. These data indicate that the conserved glycine residues in TM2 are involved in Wzz:Wzz interactions, and provide insight into key interactions that drive Oag modal length control.
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Affiliation(s)
- Magdalene Papadopoulos
- School of Biological Sciences, Department of Molecular & Cellular Biology, Research Centre for Infectious Diseases, University of Adelaide, Adelaide 5005, Australia
| | - Elizabeth Ngoc Hoa Tran
- School of Biological Sciences, Department of Molecular & Cellular Biology, Research Centre for Infectious Diseases, University of Adelaide, Adelaide 5005, Australia
| | - Gerald Laurence Murray
- School of Biological Sciences, Department of Molecular & Cellular Biology, Research Centre for Infectious Diseases, University of Adelaide, Adelaide 5005, Australia
| | - Renato Morona
- School of Biological Sciences, Department of Molecular & Cellular Biology, Research Centre for Infectious Diseases, University of Adelaide, Adelaide 5005, Australia
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Emanuele AA, Garcia GA. Mechanism of Action and Initial, In Vitro SAR of an Inhibitor of the Shigella flexneri Virulence Regulator VirF. PLoS One 2015; 10:e0137410. [PMID: 26352269 PMCID: PMC4564171 DOI: 10.1371/journal.pone.0137410] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/17/2015] [Indexed: 12/19/2022] Open
Abstract
Shigella spp. are among the main causative agents of acute diarrheal illness and claim more than 1 million lives per year worldwide. There are multiple bacterial genes that control the pathogenesis of Shigella, but the virF gene may be the most important. This gene, located on the primary pathogenicity island of Shigella, encodes VirF, an AraC-family transcriptional activator that is responsible for initiating the pathogenesis cycle in Shigella. We have previously shown that it is possible to attenuate the virulence of Shigella flexneri via small molecule inhibition of VirF. In this study, we probed the mechanism of action of our small molecule inhibitors of VirF. To enable these studies, we have developed a homologous and efficient expression and purification system for VirF and have optimized two different in vitro VirF-DNA binding assays. We have determined that one of our HTS hit compounds inhibits VirF binding to DNA with a calculated Ki similar to the effective doses seen in our transcriptional activation and virulence screens. This is consistent with inhibition of DNA binding as the mechanism of action of this hit compound. We have also screened 15 commercially sourced analogs of this compound and deduced an initial SAR from the approximately 100-fold range in activities. Our four other HTS hit compounds do not inhibit DNA binding and yet they do block VirF activity. This suggests that multiple agents with different molecular mechanisms of inhibition of VirF could be developed. Pursuing hits with different mechanisms of action could be a powerful approach to enhance activity and to circumvent resistance that could develop to any one of these agents.
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Affiliation(s)
- Anthony A. Emanuele
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States of America
| | - George A. Garcia
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States of America
- * E-mail:
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Leuzzi A, Di Martino ML, Campilongo R, Falconi M, Barbagallo M, Marcocci L, Pietrangeli P, Casalino M, Grossi M, Micheli G, Colonna B, Prosseda G. Multifactor Regulation of the MdtJI Polyamine Transporter in Shigella. PLoS One 2015; 10:e0136744. [PMID: 26313003 PMCID: PMC4636849 DOI: 10.1371/journal.pone.0136744] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 08/06/2015] [Indexed: 01/19/2023] Open
Abstract
The polyamine profile of Shigella, the etiological agent of bacillary dysentery in humans, differs markedly from that of E. coli, its innocuous commensal ancestor. Pathoadaptive mutations such as the loss of cadaverine and the increase of spermidine favour the full expression of the virulent phenotype of Shigella. Spermidine levels affect the expression of the MdtJI complex, a recently identified efflux pump belonging to the small multi-drug resistance family of transporters. In the present study, we have addressed the regulation of the mdtJI operon in Shigella by asking which factors influence its expression as compared to E. coli. In particular, after identifying the mdtJI promoter by primer extension analysis, in vivo transcription assays and gel-retardation experiments were carried out to get insight on the silencing of mdtJI in E. coli. The results indicate that H-NS, a major nucleoid protein, plays a key role in repressing the mdtJI operon by direct binding to the regulatory region. In the Shigella background mdtJI expression is increased by the high levels of spermidine typically found in this microorganism and by VirF, the plasmid-encoded regulator of the Shigella virulence regulatory cascade. We also show that the expression of mdtJI is stimulated by bile components. Functional analyses reveal that MdtJI is able to promote the excretion of putrescine, the spermidine precursor. This leads us to consider the MdtJI complex as a possible safety valve allowing Shigella to maintain spermidine to a level optimally suited to survival within infected macrophages and, at the same time, prevent toxicity due to spermidine over-accumulation.
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Affiliation(s)
- Adriano Leuzzi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Maria Letizia Di Martino
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Rosaria Campilongo
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Maurizio Falconi
- Laboratorio di Genetica Molecolare e dei Microrganismi, Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Via Gentile III da Varano, Camerino, Italy
| | - Marialuisa Barbagallo
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Lucia Marcocci
- Dipartimento di Biochimica, Sapienza Università di Roma, P.le A. Moro 5, 00185, Roma, Italy
| | - Paola Pietrangeli
- Dipartimento di Biochimica, Sapienza Università di Roma, P.le A. Moro 5, 00185, Roma, Italy
| | - Mariassunta Casalino
- Dipartimento di Scienze, Università Roma Tre, Viale G. Marconi 446, 00146, Roma, Italy
| | - Milena Grossi
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Gioacchino Micheli
- Istituto di Biologia e Patologia molecolari CNR, P.le A. Moro 5, 00185, Roma, Italy
| | - Bianca Colonna
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
| | - Gianni Prosseda
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Biologia e Biotecnologie “C. Darwin”, Sapienza Università di Roma, Via dei Sardi 70, 00185, Roma, Italy
- * E-mail:
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Gray MD, Lampel KA, Strockbine NA, Fernandez RE, Melton-Celsa AR, Maurelli AT. Clinical isolates of Shiga toxin 1a-producing Shigella flexneri with an epidemiological link to recent travel to Hispañiola. Emerg Infect Dis 2015; 20:1669-77. [PMID: 25271406 PMCID: PMC4193171 DOI: 10.3201/eid2010.140292] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Shiga toxins (Stx) are cytotoxins involved in severe human intestinal disease. These toxins are commonly found in Shigella dysenteriae serotype 1 and Shiga-toxin-producing Escherichia coli; however, the toxin genes have been found in other Shigella species. We identified 26 Shigella flexneri serotype 2 strains isolated by public health laboratories in the United States during 2001-2013, which encode the Shiga toxin 1a gene (stx1a). These strains produced and released Stx1a as measured by cytotoxicity and neutralization assays using anti-Stx/Stx1a antiserum. The release of Stx1a into culture supernatants increased ≈100-fold after treatment with mitomycin C, suggesting that stx1a is carried by a bacteriophage. Infectious phage were found in culture supernatants and increased ≈1,000-fold with mitomycin C. Whole-genome sequencing of several isolates and PCR analyses of all strains confirmed that stx1a was carried by a lambdoid bacteriophage. Furthermore, all patients who reported foreign travel had recently been to Hispañiola, suggesting that emergence of these novel strains is associated with that region.
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35
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Jakhetia R, Verma NK. Identification and Molecular Characterisation of a Novel Mu-Like Bacteriophage, SfMu, of Shigella flexneri. PLoS One 2015; 10:e0124053. [PMID: 25902138 PMCID: PMC4406740 DOI: 10.1371/journal.pone.0124053] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/24/2015] [Indexed: 11/18/2022] Open
Abstract
S. flexneri is the leading cause of bacillary dysentery in the developing countries. Several temperate phages originating from this host have been characterised. However, all S. flexneri phages known to date are lambdoid phages, which have the ability to confer the O-antigen modification of their host. In this study, we report the isolation and characterisation of a novel Mu-like phage from a serotype 4a strain of S. flexneri. The genome of phage SfMu is composed of 37,146 bp and is predicted to contain 55 open reading frames (orfs). Comparative genome analysis of phage SfMu with Mu and other Mu-like phages revealed that SfMu is closely related to phage Mu, sharing >90% identity with majority of its proteins. Moreover, investigation of phage SfMu receptor on the surface of the host cell revealed that the O-antigen of the host serves as the receptor for the adsorption of phage SfMu. This study also demonstrates pervasiveness of SfMu phage in S. flexneri, by identifying complete SfMu prophage strains of serotype X and Y, and remnants of SfMu in strains belonging to 4 other serotypes, thereby indicating that transposable phages in S. flexneri are not uncommon. The findings of this study contribute an advance in our current knowledge of S. flexneri phages and will also play a key role in understanding the evolution of S. flexneri.
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Affiliation(s)
- Richa Jakhetia
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Naresh K. Verma
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
- * E-mail:
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36
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Kuehl CJ, Dragoi AM, Agaisse H. The Shigella flexneri type 3 secretion system is required for tyrosine kinase-dependent protrusion resolution, and vacuole escape during bacterial dissemination. PLoS One 2014; 9:e112738. [PMID: 25405985 PMCID: PMC4236203 DOI: 10.1371/journal.pone.0112738] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/14/2014] [Indexed: 01/29/2023] Open
Abstract
Shigella flexneri is a human pathogen that triggers its own entry into intestinal cells and escapes primary vacuoles to gain access to the cytosolic compartment. As cytosolic and motile bacteria encounter the cell cortex, they spread from cell to cell through formation of membrane protrusions that resolve into secondary vacuoles in adjacent cells. Here, we examined the roles of the Type 3 Secretion System (T3SS) in S. flexneri dissemination in HT-29 intestinal cells infected with the serotype 2a strain 2457T. We generated a 2457T strain defective in the expression of MxiG, a central component of the T3SS needle apparatus. As expected, the ΔmxiG strain was severely affected in its ability to invade HT-29 cells, and expression of mxiG under the control of an arabinose inducible expression system (ΔmxiG/pmxiG) restored full infectivity. In this experimental system, removal of the inducer after the invasion steps (ΔmxiG/pmxiG (Ara withdrawal)) led to normal actin-based motility in the cytosol of HT-29 cells. However, the time spent in protrusions until vacuole formation was significantly increased. Moreover, the number of formed protrusions that failed to resolve into vacuoles was also increased. Accordingly, the ΔmxiG/pmxiG (Ara withdrawal) strain failed to trigger tyrosine phosphorylation in membrane protrusions, a signaling event that is required for the resolution of protrusions into vacuoles. Finally, the ΔmxiG/pmxiG (Ara withdrawal) strain failed to escape from the formed secondary vacuoles, as previously reported in non-intestinal cells. Thus, the T3SS system displays multiple roles in S. flexneri dissemination in intestinal cells, including the tyrosine kinase signaling-dependent resolution of membrane protrusions into secondary vacuoles, and the escape from the formed secondary vacuoles.
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Affiliation(s)
- Carole J. Kuehl
- Department of Microbial Pathogenesis, Yale School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, United States of America
| | - Ana-Maria Dragoi
- Department of Microbial Pathogenesis, Yale School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, United States of America
| | - Hervé Agaisse
- Department of Microbial Pathogenesis, Yale School of Medicine, Boyer Center for Molecular Medicine, New Haven, Connecticut, United States of America
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Grishin AM, Condos TEC, Barber KR, Campbell-Valois FX, Parsot C, Shaw GS, Cygler M. Structural basis for the inhibition of host protein ubiquitination by Shigella effector kinase OspG. Structure 2014; 22:878-88. [PMID: 24856362 DOI: 10.1016/j.str.2014.04.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 03/19/2014] [Accepted: 04/09/2014] [Indexed: 11/30/2022]
Abstract
Shigella invasion of its human host is assisted by T3SS-delivered effector proteins. The OspG effector kinase binds ubiquitin and ubiquitin-loaded E2-conjugating enzymes, including UbcH5b and UbcH7, and attenuates the host innate immune NF-kB signaling. We present the structure of OspG bound to the UbcH7∼Ub conjugate. OspG has a minimal kinase fold lacking the activation loop of regulatory kinases. UbcH7∼Ub binds OspG at sites remote from the kinase active site, yet increases its kinase activity. The ubiquitin is positioned in the "open" conformation with respect to UbcH7 using its I44 patch to interact with the C terminus of OspG. UbcH7 binds to OspG using two conserved loops essential for E3 ligase recruitment. The interaction of the UbcH7∼Ub with OspG is remarkably similar to the interaction of an E2∼Ub with a HECT E3 ligase. OspG interferes with the interaction of UbcH7 with the E3 parkin and inhibits the activity of the E3.
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Affiliation(s)
- Andrey M Grishin
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada
| | - Tara E C Condos
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Kathryn R Barber
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | | | - Claude Parsot
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris, France; INSERM, U786, 75015, Paris, France
| | - Gary S Shaw
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Miroslaw Cygler
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada; Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada.
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Abstract
Shigella spp. are intracytosolic gram-negative pathogens that cause disease by invasion and spread through the colonic mucosa, utilizing host cytoskeletal components to form propulsive actin tails. We have previously identified the host factor Toca-1 as being recruited to intracellular S. flexneri and being required for efficient bacterial actin tail formation. We show that at early times during infection (40 min.), the type three-secreted effector protein IcsB recruits Toca-1 to intracellular bacteria and that recruitment of Toca-1 is associated with repression of recruitment of LC3, as well as with repression of recruitment of the autophagy marker NDP52, around these intracellular bacteria. LC3 is best characterized as a marker of autophagosomes, but also marks phagosomal membranes in the process LC3-associated phagocytosis. IcsB has previously been demonstrated to be required for S. flexneri evasion of autophagy at late times during infection (4-6 hr) by inhibiting binding of the autophagy protein Atg5 to the Shigella surface protein IcsA (VirG). Our results suggest that IcsB and Toca-1 modulation of LC3 recruitment restricts LC3-associated phagocytosis and/or LC3 recruitment to vacuolar membrane remnants. Together with published results, our findings suggest that IcsB inhibits innate immune responses in two distinct ways, first, by inhibiting LC3-associated phagocytosis and/or LC3 recruitment to vacuolar membrane remnants early during infection, and second, by inhibiting autophagy late during infection.
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Affiliation(s)
- Leigh A. Baxt
- Department of Medicine, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marcia B. Goldberg
- Department of Medicine, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
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Costa SCP, Lesser CF. A multifunctional region of the Shigella type 3 effector IpgB1 is important for secretion from bacteria and membrane targeting in eukaryotic cells. PLoS One 2014; 9:e93461. [PMID: 24718571 PMCID: PMC3981709 DOI: 10.1371/journal.pone.0093461] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 03/05/2014] [Indexed: 11/29/2022] Open
Abstract
Type 3 secretion systems are complex nanomachines used by many Gram–negative bacteria to deliver tens of proteins (effectors) directly into host cells. Once delivered into host cells, effectors often target to specific cellular loci where they usurp host cell processes to their advantage. Here, using the yeast model system, we identify the membrane localization domain (MLD) of IpgB1, a stretch of 20 amino acids enriched for hydrophobic residues essential for the targeting of this effector to the plasma membrane. Embedded within these residues are ten that define the IpgB1 chaperone-binding domain for Spa15. As observed with dedicated class IA chaperones that mask hydrophobic MLDs, Spa15, a class IB chaperone, promotes IpgB1 stability by binding this hydrophobic region. However, despite being stable, an IpgB1 allele that lacks the MLD is not recognized as a secreted substrate. Similarly, deletion of the chaperone binding domains of IpgB1 and three additional Spa15-dependent effectors result in alleles that are no longer recognized as secreted substrates despite the presence of intact N-terminal secretion signal sequences. This is in contrast with MLD-containing effectors that bind class IA dedicated chaperones, as deletion of the MLD of these effectors alleviates the chaperone requirement for secretion. These observations indicate that at least for substrates of class IB chaperones, the chaperone-effector complex plays a major role in defining type 3 secreted proteins and highlight how a single region of an effector can play important roles both within prokaryotic and eukaryotic cells.
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Affiliation(s)
- Sonia C. P. Costa
- Department of Medicine (Microbiology and Immunobiology), Division of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Cammie F. Lesser
- Department of Medicine (Microbiology and Immunobiology), Division of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, Cambridge, Massachusetts, United States of America
- * E-mail:
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Scribano D, Petrucca A, Pompili M, Ambrosi C, Bruni E, Zagaglia C, Prosseda G, Nencioni L, Casalino M, Polticelli F, Nicoletti M. Polar localization of PhoN2, a periplasmic virulence-associated factor of Shigella flexneri, is required for proper IcsA exposition at the old bacterial pole. PLoS One 2014; 9:e90230. [PMID: 24587292 PMCID: PMC3937361 DOI: 10.1371/journal.pone.0090230] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/27/2014] [Indexed: 12/18/2022] Open
Abstract
Proper protein localization is critical for bacterial virulence. PhoN2 is a virulence-associated ATP-diphosphohydrolase (apyrase) involved in IcsA-mediated actin-based motility of S. flexneri. Herein, by analyzing a ΔphoN2 mutant of the S. flexneri strain M90T and by generating phoN2::HA fusions, we show that PhoN2, is a periplasmic protein that strictly localizes at the bacterial poles, with a strong preference for the old pole, the pole where IcsA is exposed, and that it is required for proper IcsA exposition. PhoN2-HA was found to be polarly localized both when phoN2::HA was ectopically expressed in a Escherichia coli K-12 strain and in a S. flexneri virulence plasmid-cured mutant, indicating a conserved mechanism of PhoN2 polar delivery across species and that neither IcsA nor the expression of other virulence-plasmid encoded genes are involved in this process. To assess whether PhoN2 and IcsA may interact, two-hybrid and cross-linking experiments were performed. While no evidence was found of a PhoN2-IcsA interaction, unexpectedly the outer membrane protein A (OmpA) was shown to bind PhoN2-HA through its periplasmic-exposed C-terminal domain. Therefore, to identify PhoN2 domains involved in its periplasmic polar delivery as well as in the interaction with OmpA, a deletion and a set of specific amino acid substitutions were generated. Analysis of these mutants indicated that neither the (183)PAPAP(187) motif of OmpA, nor the N-terminal polyproline (43)PPPP(46) motif and the Y155 residue of PhoN2 are involved in this interaction while P45, P46 and Y155 residues were found to be critical for the correct folding and stability of the protein. The relative rapid degradation of these amino acid-substituted recombinant proteins was found to be due to unknown S. flexneri-specific protease(s). A model depicting how the PhoN2-OmpA interaction may contribute to proper polar IcsA exposition in S. flexneri is presented.
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Affiliation(s)
- Daniela Scribano
- Dipartimento di Scienze Sperimentali e Cliniche, Università “G. D'Annunzio”, Chieti, Italy
| | - Andrea Petrucca
- Dipartimento di Scienze Sperimentali e Cliniche, Università “G. D'Annunzio”, Chieti, Italy
| | - Monica Pompili
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Cecilia Ambrosi
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Elena Bruni
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Carlo Zagaglia
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Gianni Prosseda
- Dipartimento di Biologia e Biotecnologie “C. Darwin”, Università Sapienza di Roma, Rome, Italy
| | - Lucia Nencioni
- Dipartimento di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | | | - Fabio Polticelli
- Dipartimento di Scienze, Università di “Roma Tre”, Rome, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di “Roma Tre”, Rome, Italy
| | - Mauro Nicoletti
- Dipartimento di Scienze Sperimentali e Cliniche, Università “G. D'Annunzio”, Chieti, Italy
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Dohlich K, Zumsteg AB, Goosmann C, Kolbe M. A substrate-fusion protein is trapped inside the Type III Secretion System channel in Shigella flexneri. PLoS Pathog 2014; 10:e1003881. [PMID: 24453973 PMCID: PMC3894212 DOI: 10.1371/journal.ppat.1003881] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/27/2013] [Indexed: 11/18/2022] Open
Abstract
The Type III Secretion System (T3SS) is a macromolecular complex used by Gram-negative bacteria to secrete effector proteins from the cytoplasm across the bacterial envelope in a single step. For many pathogens, the T3SS is an essential virulence factor that enables the bacteria to interact with and manipulate their respective host. A characteristic structural feature of the T3SS is the needle complex (NC). The NC resembles a syringe with a basal body spanning both bacterial membranes and a long needle-like structure that protrudes from the bacterium. Based on the paradigm of a syringe-like mechanism, it is generally assumed that effectors and translocators are unfolded and secreted from the bacterial cytoplasm through the basal body and needle channel. Despite extensive research on T3SS, this hypothesis lacks experimental evidence and the mechanism of secretion is not fully understood. In order to elucidate details of the T3SS secretion mechanism, we generated fusion proteins consisting of a T3SS substrate and a bulky protein containing a knotted motif. Because the knot cannot be unfolded, these fusions are accepted as T3SS substrates but remain inside the NC channel and obstruct the T3SS. To our knowledge, this is the first time substrate fusions have been visualized together with isolated NCs and we demonstrate that substrate proteins are secreted directly through the channel with their N-terminus first. The channel physically encloses the fusion protein and shields it from a protease and chemical modifications. Our results corroborate an elementary understanding of how the T3SS works and provide a powerful tool for in situ-structural investigations in the future. This approach might also be applicable to other protein secretion systems that require unfolding of their substrates prior to secretion. Type III Secretion Systems (T3SS) secrete bacterial effector proteins from the cytoplasm across the cell wall, but mechanistic details of this process remain mostly elusive. We locked the T3SS of Shigella flexneri in an actively secreting state by expression of substrate fusions that consist of a functional translocator and a stably-folded knotted protein. Although recognized as T3SS substrates, the fusions are not released from secreting Shigella and impede transport of other effector proteins by obstructing the T3SS channel. We localized the fusion at isolated channels and observed that the translocator is secreted with the N-terminus first. We further demonstrate that the channel physically encloses the partially transported substrate. Our analysis elucidates important steps of the T3SS mechanism. Furthermore, we developed fusion proteins useful for advanced structural investigations of one of the most complex bacterial virulence devices known and our approach may help to also understand other protein transport mechanisms.
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Affiliation(s)
- Kim Dohlich
- Structural Systems Biology Group, Max-Planck-Institute for Infection Biology, Berlin, Germany
| | - Anna Brotcke Zumsteg
- Department of Cellular Microbiology, Max-Planck-Institute for Infection Biology, Berlin, Germany
| | - Christian Goosmann
- Microscopy Core Facility, Max-Planck-Institute for Infection Biology, Berlin, Germany
| | - Michael Kolbe
- Structural Systems Biology Group, Max-Planck-Institute for Infection Biology, Berlin, Germany
- * E-mail:
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Sun Q, Knirel YA, Lan R, Wang J, Senchenkova SN, Shashkov AS, Wang Y, Wang Y, Luo X, Xu J. Dissemination and serotype modification potential of pSFxv_2, an O-antigen PEtN modification plasmid in Shigella flexneri. Glycobiology 2013; 24:305-13. [PMID: 24379081 DOI: 10.1093/glycob/cwt115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The O-antigens of all Shigella flexneri serotypes, except serotype 6, share a linear tetrasaccharide repeat composed of one N-acetylglucosamine and three l-rhamnose residues, and differences between the serotypes are due to modification of various monosaccharide residues with glucosyl and/or O-acetyl and/or phosphoethanolamine (PEtN) groups. Plasmid-borne opt (formerly lpt-O) gene encoding a PEtN transferase which modifies the O-antigens of S. flexneri serotype X, 4a and Y strains and converts the hosts into MASF IV-1 (E1037) positive "variant" (v) Xv, 4av and Yv serotypes, respectively. In this study, we showed that the opt-carrying plasmid pSFxv_2 can transform strains of all S. flexneri serotypes (1-6) to confer them with the MASF IV-1 epitope recognized by monoclonal antibody MASF IV-1 and typing antiserum IV. The transformants possessed modified O-antigens with a PEtN group(s) at position 3 of one or two rhamnose residues. In some serotypes, the PEtN modification competed or/and interfered with glucosylation and O-acetylation at the same or its neighboring sugar residue. We also showed that the plasmid pSFxv_2 is mobilizable to other S. flexneri strains by conjugation. Although pSFxv_2-harboring S. flexneri strains found in clinical infections are restricted to serotypes Xv, 4av, Yv and, possibly, 6v, our results demonstrate a high potential of dissemination of this plasmid in S. flexneri and emergence of new S. flexneri serotypes.
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Affiliation(s)
- Qiangzheng Sun
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, China CDC, P.O Box 5, Changping, Beijing, China
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Mostowy S, Boucontet L, Mazon Moya MJ, Sirianni A, Boudinot P, Hollinshead M, Cossart P, Herbomel P, Levraud JP, Colucci-Guyon E. The zebrafish as a new model for the in vivo study of Shigella flexneri interaction with phagocytes and bacterial autophagy. PLoS Pathog 2013; 9:e1003588. [PMID: 24039575 PMCID: PMC3764221 DOI: 10.1371/journal.ppat.1003588] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 07/19/2013] [Indexed: 01/02/2023] Open
Abstract
Autophagy, an ancient and highly conserved intracellular degradation process, is viewed as a critical component of innate immunity because of its ability to deliver cytosolic bacteria to the lysosome. However, the role of bacterial autophagy in vivo remains poorly understood. The zebrafish (Danio rerio) has emerged as a vertebrate model for the study of infections because it is optically accessible at the larval stages when the innate immune system is already functional. Here, we have characterized the susceptibility of zebrafish larvae to Shigella flexneri, a paradigm for bacterial autophagy, and have used this model to study Shigella-phagocyte interactions in vivo. Depending on the dose, S. flexneri injected in zebrafish larvae were either cleared in a few days or resulted in a progressive and ultimately fatal infection. Using high resolution live imaging, we found that S. flexneri were rapidly engulfed by macrophages and neutrophils; moreover we discovered a scavenger role for neutrophils in eliminating infected dead macrophages and non-immune cell types that failed to control Shigella infection. We observed that intracellular S. flexneri could escape to the cytosol, induce septin caging and be targeted to autophagy in vivo. Depletion of p62 (sequestosome 1 or SQSTM1), an adaptor protein critical for bacterial autophagy in vitro, significantly increased bacterial burden and host susceptibility to infection. These results show the zebrafish larva as a new model for the study of S. flexneri interaction with phagocytes, and the manipulation of autophagy for anti-bacterial therapy in vivo. Autophagy, an ancient and highly conserved intracellular degradation process, is viewed as a critical component of innate immunity because of its ability to deliver cytosolic bacteria to the lysosome. However, a complete understanding of the molecules and mechanisms restricting cytosolic bacteria has not been obtained, and the role of bacterial autophagy in vivo remains poorly understood. Shigella flexneri are human-adapted Escherichia coli that have gained the ability to invade the colonic mucosa, causing inflammation and diarrhea. The intracellular lifestyle of this pathogen has been well-studied in vitro, and Shigella has recently gained recognition as a paradigm of bacterial autophagy. We show that the zebrafish larva represents a valuable new host for the analysis of S. flexneri infection. Interactions between bacteria and host phagocytes can be imaged at high resolution in vivo, and the zebrafish model should prove useful for understanding the cell biology of Shigella infection. We use zebrafish larvae to investigate the role of bacterial autophagy in host defense, and observed that the perturbation of autophagy can adversely affect host survival in response to Shigella infection. Therefore, the zebrafish constitutes a valuable system to develop new strategies aimed at pathogen clearance by manipulation of anti-bacterial autophagy.
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Affiliation(s)
- Serge Mostowy
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
- Institut Pasteur, Unité des Interactions Bactéries-Cellules, Département de Biologie Cellulaire et Infection, Paris, France
- Inserm, U604, Paris, France
- INRA, USC2020, Paris, France
- * E-mail: (SM); (ECG)
| | - Laurent Boucontet
- Institut Pasteur, Unité Macrophages et Développement de l'Immunité, Département de Biologie du Développement et des Cellules Souches, Paris, France
- CNRS, URA2578, Paris, France
| | - Maria J. Mazon Moya
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Andrea Sirianni
- Section of Microbiology, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Pierre Boudinot
- INRA, Virologie et Immunologie Moléculaire, Jouy-en-Josas, France
| | - Michael Hollinshead
- Section of Virology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Pascale Cossart
- Institut Pasteur, Unité des Interactions Bactéries-Cellules, Département de Biologie Cellulaire et Infection, Paris, France
- Inserm, U604, Paris, France
- INRA, USC2020, Paris, France
| | - Philippe Herbomel
- Institut Pasteur, Unité Macrophages et Développement de l'Immunité, Département de Biologie du Développement et des Cellules Souches, Paris, France
- CNRS, URA2578, Paris, France
| | - Jean-Pierre Levraud
- Institut Pasteur, Unité Macrophages et Développement de l'Immunité, Département de Biologie du Développement et des Cellules Souches, Paris, France
- CNRS, URA2578, Paris, France
| | - Emma Colucci-Guyon
- Institut Pasteur, Unité Macrophages et Développement de l'Immunité, Département de Biologie du Développement et des Cellules Souches, Paris, France
- CNRS, URA2578, Paris, France
- * E-mail: (SM); (ECG)
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Fu P, Zhang X, Jin M, Xu L, Wang C, Xia Z, Zhu Y. Complex structure of OspI and Ubc13: the molecular basis of Ubc13 deamidation and convergence of bacterial and host E2 recognition. PLoS Pathog 2013; 9:e1003322. [PMID: 23633953 PMCID: PMC3636029 DOI: 10.1371/journal.ppat.1003322] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 03/07/2013] [Indexed: 11/24/2022] Open
Abstract
Ubc13 is an important ubiquitin-conjugating (E2) enzyme in the NF-κB signaling pathway. The Shigella effector OspI targets Ubc13 and deamidates Gln100 of Ubc13 to a glutamic acid residue, leading to the inhibition of host inflammatory responses. Here we report the crystal structure of the OspI-Ubc13 complex at 2.3 Å resolution. The structure reveals that OspI uses two differently charged regions to extensively interact with the α1 helix, L1 loop and L2 loop of Ubc13. The Gln100 residue is bound within the hydrophilic catalytic pocket of OspI. A comparison between Ubc13-bound and wild-type free OspI structures revealed that Ubc13 binding induces notable structural reassembly of the catalytic pocket, suggesting that substrate binding might be involved in the catalysis of OspI. The OspI-binding sites in Ubc13 largely overlap with the binding residues for host ubiquitin E3 ligases and a deubiquitinating enzyme, which suggests that the bacterial effector and host proteins exploit the same surface on Ubc13 for specific recognition. Biochemical results indicate that both of the differently charged regions in OspI are important for the interaction with Ubc13, and the specificity determinants in Ubc13 for OspI recognition reside in the distinct residues in the α1 helix and L2 region. Our study reveals the molecular basis of Ubc13 deamidation by OspI, as well as a convergence of E2 recognition by bacterial and host proteins. The Gram-negative pathogenic bacterium Shigella infects human intestinal epithelium cells and causes severe inflammatory colitis (bacillary dysentery). Shigella harbors an approximately 220-kb virulence plasmid that encodes a type III secretion system (T3SS) protein secretion apparatus and many effector proteins. Using the T3SS, Shigella delivers the effector proteins into the host cells, targeting key signal molecules and manipulating the host physiological processes and thereby promoting infection and multiplication. OspI, a newly identified Shigella effector, targets the host Ubc13 protein, a critical ubiquitin-conjugating enzyme in the NF-κB signaling pathway. OspI deamidates Gln100 of Ubc13 to a glutamic acid residue, thereby disrupting TRAF6-catalyzed polyubiquitination and dampening host inflammatory responses. However, the structural mechanism of this specific deamidation is unclear. Through crystallography, we have determined the structure of the OspI-Ubc13 complex. The structure illustrates how OspI interacts with Ubc13 and how Ubc13 induces conformational changes in OspI. Combining structural analysis and biochemical assays, we revealed how OspI distinguishes Ubc13 from other ubiquitin conjugating enzymes and found that OspI binds to the same surface region on Ubc13 as host TRAF6, CHIP and OTUB1. Our study sheds light on the molecular mechanism of Ubc13 deamidation by OspI and provides new insights into E2 recognition by bacterial and host proteins.
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Affiliation(s)
- Panhan Fu
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoqing Zhang
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Mengmeng Jin
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Li Xu
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chong Wang
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zongping Xia
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yongqun Zhu
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
- * E-mail:
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Abstract
Nonstop mRNAs pose a challenge for bacteria, because translation cannot terminate efficiently without a stop codon. The trans-translation pathway resolves nonstop translation complexes by removing the nonstop mRNA, the incomplete protein, and the stalled ribosome. P1 co-transduction experiments demonstrated that tmRNA, a key component of the trans-translation pathway, is essential for viability in Shigella flexneri. tmRNA was previously shown to be dispensable in the closely related species Escherichia coli, because E. coli contains a backup system for trans-translation mediated by the alternative release factor ArfA. Genome sequence analysis showed that S. flexneri does not have a gene encoding ArfA. E. coli ArfA could suppress the requirement for tmRNA in S. flexneri, indicating that tmRNA is essential in S. flexneri because there is no functional backup system. These data suggest that resolution of nonstop translation complexes is required for most bacteria.
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Affiliation(s)
- Nitya S. Ramadoss
- Pennsylvania State University, Department of Biochemistry & Molecular Biology, University Park, Pennsylvania, United States of America
| | - Xin Zhou
- Pennsylvania State University, Department of Biochemistry & Molecular Biology, University Park, Pennsylvania, United States of America
| | - Kenneth C. Keiler
- Pennsylvania State University, Department of Biochemistry & Molecular Biology, University Park, Pennsylvania, United States of America
- * E-mail:
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Teh MY, Morona R. Identification of Shigella flexneri IcsA residues affecting interaction with N-WASP, and evidence for IcsA-IcsA co-operative interaction. PLoS One 2013; 8:e55152. [PMID: 23405119 PMCID: PMC3566212 DOI: 10.1371/journal.pone.0055152] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 12/21/2012] [Indexed: 12/17/2022] Open
Abstract
The Shigella flexneri IcsA (VirG) protein is a polarly distributed outer membrane protein that is a fundamental virulence factor which interacts with neural Wiskott-Aldrich syndrome protein (N-WASP). The activated N-WASP then activates the Arp2/3 complex which initiates de novo actin nucleation and polymerisation to form F-actin comet tails and allows bacterial cell-to-cell spreading. In a previous study, IcsA was found to have three N-WASP interacting regions (IRs): IR I (aa 185-312), IR II (aa 330-382) and IR III (aa 508-730). The aim of this study was to more clearly define N-WASP interacting regions II and III by site-directed mutagenesis of specific amino acids. Mutant IcsA proteins were expressed in both smooth lipopolysaccharide (S-LPS) and rough LPS (R-LPS) S. flexneri strains and characterised for IcsA production level, N-WASP recruitment and F-actin comet tail formation. We have successfully identified new amino acids involved in N-WASP recruitment within different N-WASP interacting regions, and report for the first time using co-expression of mutant IcsA proteins, that N-WASP activation involves interactions with different regions on different IcsA molecules as shown by Arp3 recruitment. In addition, our findings suggest that autochaperone (AC) mutant protein production was not rescued by another AC region provided in trans, differing to that reported for two other autotransporters, PrtS and BrkA autotransporters.
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Affiliation(s)
- Min Yan Teh
- Discipline of Microbiology and Immunology, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Renato Morona
- Discipline of Microbiology and Immunology, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
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Ambrosi C, Pompili M, Scribano D, Zagaglia C, Ripa S, Nicoletti M. Outer membrane protein A (OmpA): a new player in shigella flexneri protrusion formation and inter-cellular spreading. PLoS One 2012; 7:e49625. [PMID: 23166731 PMCID: PMC3498225 DOI: 10.1371/journal.pone.0049625] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 10/11/2012] [Indexed: 11/24/2022] Open
Abstract
Outer membrane protein A (OmpA) is a multifaceted predominant outer membrane protein of Escherichia coli and other Enterobacteriaceae whose role in the pathogenesis of various bacterial infections has recently been recognized. Here, the role of OmpA on the virulence of Shigella flexneri has been investigated. An ompA mutant of wild-type S. flexneri 5a strain M90T was constructed (strain HND92) and it was shown to be severely impaired in cell-to-cell spreading since it failed to plaque on HeLa cell monolayers. The lack of OmpA significantly reduced the levels of IcsA while the levels of cell associated and released IcsP-cleaved 95 kDa amino-terminal portion of the mature protein were similar. Nevertheless, the ompA mutant displayed IcsA exposed across the entire bacterial surface. Surprisingly, the ompA mutant produced proper F-actin comet tails, indicating that the aberrant IcsA exposition at bacterial lateral surface did not affect proper activation of actin-nucleating proteins, suggesting that the absence of OmpA likely unmasks mature or cell associated IcsA at bacterial lateral surface. Moreover, the ompA mutant was able to invade and to multiply within HeLa cell monolayers, although internalized bacteria were found to be entrapped within the host cell cytoplasm. We found that the ompA mutant produced significantly less protrusions than the wild-type strain, indicating that this defect could be responsible of its inability to plaque. Although we could not definitely rule out that the ompA mutation might exert pleiotropic effects on other S. flexneri genes, complementation of the ompA mutation with a recombinant plasmid carrying the S. flexneri ompA gene clearly indicated that a functional OmpA protein is required and sufficient for proper IcsA exposition, plaque and protrusion formation. Moreover, an independent ompA mutant was generated. Since we found that both mutants displayed identical virulence profile, these results further supported the findings presented in this study.
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Affiliation(s)
- Cecilia Ambrosi
- Dip. di Scienze Sperimentali e Cliniche, Università “G. D’Annunzio’ di Chieti, Chieti, Italy
| | - Monica Pompili
- Dip. di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | | | - Carlo Zagaglia
- Dip. di Sanità Pubblica e Malattie Infettive Università “Sapienza” di Roma, Rome, Italy
| | - Sandro Ripa
- Dip. di Biologia Molecolare, Cellulare e Animale Università di Camerino, Camerino (MC), Italy
| | - Mauro Nicoletti
- Dip. di Scienze Sperimentali e Cliniche, Università “G. D’Annunzio’ di Chieti, Chieti, Italy
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Sun Q, Knirel YA, Lan R, Wang J, Senchenkova SN, Jin D, Shashkov AS, Xia S, Perepelov AV, Chen Q, Wang Y, Wang H, Xu J. A novel plasmid-encoded serotype conversion mechanism through addition of phosphoethanolamine to the O-antigen of Shigella flexneri. PLoS One 2012; 7:e46095. [PMID: 23049947 PMCID: PMC3458804 DOI: 10.1371/journal.pone.0046095] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 08/27/2012] [Indexed: 11/19/2022] Open
Abstract
Shigella flexneri is the major pathogen causing bacillary dysentery in developing countries. S. flexneri is divided into at least 16 serotypes based on the combination of antigenic determinants present in the O-antigen. All the serotypes (except for serotype 6) share a basic O-unit containing one N-acetyl-d-glucosamine and three l-rhamnose residues, whereas differences between the serotypes are conferred by phage-encoded glucosylation and/or O-acetylation. Serotype Xv is a newly emerged and the most prevalent serotype in China, which can agglutinate with both MASF IV-1 and 7,8 monoclonal antibodies. The factor responsible for the presence of MASF IV-1 (E1037) epitope has not yet been identified. In this study, we analyzed the LPS structure of serotype Xv strains and found that the MASF IV-1 positive phenotype depends on an O-antigen modification with a phosphoethanolamine (PEtN) group attached at position 3 of one of the rhamnose residues. A plasmid carried gene, lpt-O (LPS phosphoethanolamine transferase for O–antigen), mediates the addition of PEtN for serotype Xv and other MASF IV-1 positive strains. These findings reveal a novel serotype conversion mechanism in S. flexneri and show the necessity of further extension of the serotype classification scheme recognizing the MASF IV-1 positive strains as distinctive subtypes.
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Affiliation(s)
- Qiangzheng Sun
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China
| | - Yuriy A. Knirel
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Ruiting Lan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Jianping Wang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China
| | - Sof’ya N. Senchenkova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Dong Jin
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China
| | - Alexander S. Shashkov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Shengli Xia
- Branch for Enteric Disease Control and Prevention, Institute for Infectious Disease Control and Prevention, Henan Center for Disease Control and Prevention, Zhengzhou, China
| | - Andrei V. Perepelov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Qiang Chen
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China
| | - Yan Wang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China
| | - Haiyin Wang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China
| | - Jianguo Xu
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, China CDC, Changping, Beijing, China
- * E-mail:
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49
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Fu H, Liu L, Zhang X, Zhu Y, Zhao L, Peng J, He H, Jin Q. Common changes in global gene expression induced by RNA polymerase inhibitors in Shigella flexneri. PLoS One 2012; 7:e33240. [PMID: 22428000 PMCID: PMC3299763 DOI: 10.1371/journal.pone.0033240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 02/06/2012] [Indexed: 11/22/2022] Open
Abstract
Characterization of expression profile of organisms in response to antimicrobials provides important information on the potential mechanism of action of the drugs. The special expression signature can be used to predict whether other drugs act on the same target. Here, the common response of Shigella flexneri to two inhibitors of RNA polymerase was examined using gene expression profiling. Consistent with similar effects of the two drugs, the gene expression profiles indicated that responses of the bacteria to these drugs were roughly the same, with 225 genes affected commonly. Of them, 88 were induced and 137 were repressed. Real-time PCR was performed for selected genes to verify the microarray results. Analysis of the expression data revealed that more than 30% of the plasmid-encoded genes on the array were up-regulated by the antibiotics including virF regulon, other virulence-related genes, and genes responsible for plasmid replication, maintenance, and transfer. In addition, some chromosome-encoded genes involved in virulence and genes acquired from horizontal transfer were also significantly up-regulated. However, the expression of genes encoding the beta-subunit of RNA polymerase was increased moderately. The repressed genes include those that code for products associated with the ribosome, citrate cycle, glycolysis, thiamine biosynthesis, purine metabolism, fructose metabolism, mannose metabolism, and cold shock proteins. This study demonstrates that the two antibiotics induce rapid cessation of RNA synthesis resulting in inhibition of translation components. It also indicates that the production of virulence factors involved in intercellular dissemination, tissue invasion and inflammatory destruction may be enhanced through derepressing horizontal transfer genes by the drugs.
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Affiliation(s)
- Hua Fu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Liguo Liu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
- National Research Center for Wildlife Born Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Xiaobing Zhang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Yafang Zhu
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Lina Zhao
- Department of Biological Engineering, College of Life Sciences, Hebei United University, Hebei, People's Republic of China
| | - Junping Peng
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
| | - Hongxuan He
- National Research Center for Wildlife Born Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China
- * E-mail: (HH); (QJ)
| | - Qi Jin
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, People's Republic of China
- * E-mail: (HH); (QJ)
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50
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Bhardwaj A, Molineux IJ, Casjens SR, Cingolani G. Atomic structure of bacteriophage Sf6 tail needle knob. J Biol Chem 2011; 286:30867-30877. [PMID: 21705802 PMCID: PMC3162447 DOI: 10.1074/jbc.m111.260877] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/22/2011] [Indexed: 11/06/2022] Open
Abstract
Podoviridae are double-stranded DNA bacteriophages that use short, non-contractile tails to adsorb to the host cell surface. Within the tail apparatus of P22-like phages, a dedicated fiber known as the "tail needle" likely functions as a cell envelope-penetrating device to promote ejection of viral DNA inside the host. In Sf6, a P22-like phage that infects Shigella flexneri, the tail needle presents a C-terminal globular knob. This knob, absent in phage P22 but shared in other members of the P22-like genus, represents the outermost exposed tip of the virion that contacts the host cell surface. Here, we report a crystal structure of the Sf6 tail needle knob determined at 1.0 Å resolution. The structure reveals a trimeric globular domain of the TNF fold structurally superimposable with that of the tail-less phage PRD1 spike protein P5 and the adenovirus knob, domains that in both viruses function in receptor binding. However, P22-like phages are not known to utilize a protein receptor and are thought to directly penetrate the host surface. At 1.0 Å resolution, we identified three equivalents of l-glutamic acid (l-Glu) bound to each subunit interface. Although intimately bound to the protein, l-Glu does not increase the structural stability of the trimer nor it affects its ability to self-trimerize in vitro. In analogy to P22 gp26, we suggest the tail needle of phage Sf6 is ejected through the bacterial cell envelope during infection and its C-terminal knob is threaded through peptidoglycan pores formed by glycan strands.
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Affiliation(s)
- Anshul Bhardwaj
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Ian J Molineux
- Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, Texas 78712
| | - Sherwood R Casjens
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
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