1
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Sichel SR, Bratton BP, Salama NR. Distinct regions of H. pylori's bactofilin CcmA regulate protein-protein interactions to control helical cell shape. eLife 2022; 11:e80111. [PMID: 36073778 PMCID: PMC9507126 DOI: 10.7554/elife.80111] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 09/07/2022] [Indexed: 11/26/2022] Open
Abstract
The helical shape of Helicobacter pylori cells promotes robust stomach colonization; however, how the helical shape of H. pylori cells is determined is unresolved. Previous work identified helical-cell-shape-promoting protein complexes containing a peptidoglycan-hydrolase (Csd1), a peptidoglycan precursor synthesis enzyme (MurF), a non-enzymatic homolog of Csd1 (Csd2), non-enzymatic transmembrane proteins (Csd5 and Csd7), and a bactofilin (CcmA). Bactofilins are highly conserved, spontaneously polymerizing cytoskeletal bacterial proteins. We sought to understand CcmA's function in generating the helical shape of H. pylori cells. Using CcmA deletion analysis, in vitro polymerization, and in vivo co-immunoprecipitation experiments, we identified that the bactofilin domain and N-terminal region of CcmA are required for helical cell shape and the bactofilin domain of CcmA is sufficient for polymerization and interactions with Csd5 and Csd7. We also found that CcmA's N-terminal region inhibits interaction with Csd7. Deleting the N-terminal region of CcmA increases CcmA-Csd7 interactions and destabilizes the peptidoglycan-hydrolase Csd1. Using super-resolution microscopy, we found that Csd5 recruits CcmA to the cell envelope and promotes CcmA enrichment at the major helical axis. Thus, CcmA helps organize cell-shape-determining proteins and peptidoglycan synthesis machinery to coordinate cell wall modification and synthesis, promoting the curvature required to build a helical cell.
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Affiliation(s)
- Sophie R Sichel
- Division of Human Biology, Fred Hutchinson Cancer CenterSeattleUnited States
- Molecular Medicine and Mechanisms of Disease Graduate Program, University of WashingtonSeattleUnited States
| | - Benjamin P Bratton
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical CenterNashvilleUnited States
- Vanderbilt Institute for Infection, Immunology and InflammationNashvilleUnited States
| | - Nina R Salama
- Division of Human Biology, Fred Hutchinson Cancer CenterSeattleUnited States
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2
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Lu Y, Pang J, Wang G, Hu X, Li X, Li G, Wang X, Yang X, Li C, You X. Quantitative proteomics approach to investigate the antibacterial response of Helicobacter pylori to daphnetin, a traditional Chinese medicine monomer. RSC Adv 2021; 11:2185-2193. [PMID: 35424199 PMCID: PMC8693750 DOI: 10.1039/d0ra06677j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 12/11/2020] [Indexed: 12/20/2022] Open
Abstract
Helicobacter pylori is a Gram-negative bacterium related to the development of peptic ulcers and stomach cancer. An increasing number of infected individuals are found to harbor antibiotic-resistant H. pylori, which results in treatment failure. Daphnetin, a traditional Chinese medicine, has a broad spectrum of antibacterial activity without the development of bacterial resistance. However, the antibacterial mechanisms of daphnetin have not been elucidated entirely. To better understand the mechanisms of daphnetin's effect on H. pylori, a label-free quantitative proteomics approach based on an EASY-nLC 1200 system coupled with an Orbitrap Fusion Lumos mass spectrometer was established to investigate the key protein differences between daphnetin- and non-daphnetin-treated H. pylori. Using the criteria of greater than 1.5-fold changes and adjusted p value <0.05, proteins related to metabolism, membrane structure, nucleic acid and protein synthesis, ion binding, H. pylori colonization and infection, stress reaction, flagellar assembly and so on were found to be changed under daphnetin pressure. And the changes of selected proteins in expression level were confirmed by targeted proteomics. These new data provide us a more comprehensive horizon of the proteome changes in H. pylori that occur in response to daphnetin.
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Affiliation(s)
- Yun Lu
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Jing Pang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Genzhu Wang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Xinxin Hu
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Xue Li
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Guoqing Li
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Xiukun Wang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Xinyi Yang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Congran Li
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
| | - Xuefu You
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College Beijing 100050 China
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3
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Taylor JA, Bratton BP, Sichel SR, Blair KM, Jacobs HM, DeMeester KE, Kuru E, Gray J, Biboy J, VanNieuwenhze MS, Vollmer W, Grimes CL, Shaevitz JW, Salama NR. Distinct cytoskeletal proteins define zones of enhanced cell wall synthesis in Helicobacter pylori. eLife 2020; 9:52482. [PMID: 31916938 PMCID: PMC7012605 DOI: 10.7554/elife.52482] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 01/07/2020] [Indexed: 12/15/2022] Open
Abstract
Helical cell shape is necessary for efficient stomach colonization by Helicobacter pylori, but the molecular mechanisms for generating helical shape remain unclear. The helical centerline pitch and radius of wild-type H. pylori cells dictate surface curvatures of considerably higher positive and negative Gaussian curvatures than those present in straight- or curved-rod H. pylori. Quantitative 3D microscopy analysis of short pulses with either N-acetylmuramic acid or D-alanine metabolic probes showed that cell wall growth is enhanced at both sidewall curvature extremes. Immunofluorescence revealed MreB is most abundant at negative Gaussian curvature, while the bactofilin CcmA is most abundant at positive Gaussian curvature. Strains expressing CcmA variants with altered polymerization properties lose helical shape and associated positive Gaussian curvatures. We thus propose a model where CcmA and MreB promote PG synthesis at positive and negative Gaussian curvatures, respectively, and that this patterning is one mechanism necessary for maintaining helical shape. Round spheres, straight rods, and twisting corkscrews, bacteria come in many different shapes. The shape of bacteria is dictated by their cell wall, the strong outer barrier of the cell. As bacteria grow and multiply, they must add to their cell wall while keeping the same basic shape. The cells walls are made from long chain-like molecules via processes that are guided by protein scaffolds within the cell. Many common antibiotics, including penicillin, stop bacterial infections by interrupting the growth of cell walls. Helicobacter pylori is a common bacterium that lives in the gut and, after many years, can cause stomach ulcers and stomach cancer. H. pylori are shaped in a twisting helix, much like a corkscrew. This shape helps H. pylori to take hold and colonize the stomach. It remains unclear how H. pylori creates and maintains its helical shape. The helix is much more curved than other bacteria, and H. pylori does not have the same helpful proteins that other curved bacteria do. If H. pylori grows asymmetrically, adding more material to the cell wall on its long outer side to create a twisting helix, what controls the process? To find out, Taylor et al. grew H. pylori cells and watched how the cell walls took shape. First, a fluorescent dye was attached to the building blocks of the cell wall or to underlying proteins that were thought to help direct its growth. The cells were then imaged in 3D, and images from hundreds of cells were reconstructed to analyze the growth patterns of the bacteria’s cell wall. A protein called CcmA was found most often on the long side of the twisting H. pylori. When the CcmA protein was isolated in a dish, it spontaneously formed sheets and helical bundles, confirming its role as a structural scaffold for the cell wall. When CcmA was absent from the cell of H. pylori, Taylor et al. observed that the pattern of cell growth changed substantially. This work identifies a key component directing the growth of the cell wall of H. pylori and therefore, a new target for antibiotics. Its helical shape is essential for H. pylori to infect the gut, so blocking the action of the CcmA protein may interrupt cell wall growth and prevent stomach infections.
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Affiliation(s)
- Jennifer A Taylor
- Department of Microbiology, University of Washington, Seattle, United States.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Benjamin P Bratton
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States.,Department of Molecular Biology, Princeton University, Princeton, United States
| | - Sophie R Sichel
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular Medicine and Mechanisms of Disease Graduate Program, University of Washington, Seattle, United States
| | - Kris M Blair
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, United States
| | - Holly M Jacobs
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, United States
| | - Kristen E DeMeester
- Department of Chemistry and Biochemistry, University of Delaware, Newark, United States
| | - Erkin Kuru
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Joe Gray
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Catherine L Grimes
- Department of Chemistry and Biochemistry, University of Delaware, Newark, United States.,Department of Biological Sciences, University of Delaware, Newark, United States
| | - Joshua W Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, United States.,Department of Physics, Princeton University, Princeton, United States
| | - Nina R Salama
- Department of Microbiology, University of Washington, Seattle, United States.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Molecular Medicine and Mechanisms of Disease Graduate Program, University of Washington, Seattle, United States.,Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, United States
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4
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Abstract
Type IV secretion systems (T4SSs) are nanomachines that Gram-negative, Gram-positive bacteria, and some archaea use to transport macromolecules across their membranes into bacterial or eukaryotic host targets or into the extracellular milieu. They are the most versatile secretion systems, being able to deliver both proteins and nucleoprotein complexes into targeted cells. By mediating conjugation and/or competence, T4SSs play important roles in determining bacterial genome plasticity and diversity; they also play a pivotal role in the spread of antibiotic resistance within bacterial populations. T4SSs are also used by human pathogens such as Legionella pneumophila, Bordetella pertussis, Brucella sp., or Helicobacter pylori to sustain infection. Since they are essential virulence factors for these important pathogens, T4SSs might represent attractive targets for vaccines and therapeutics. The best-characterized conjugative T4SSs of Gram-negative bacteria are composed of twelve components that are conserved across many T4SSs. In this chapter, we will review our current structural knowledge on the T4SSs by describing the structures of the individual components and how they assemble into large macromolecular assemblies. With the combined efforts of X-ray crystallography, nuclear magnetic resonance (NMR), and more recently electron microscopy, structural biology of the T4SS has made spectacular progress during the past fifteen years and has unraveled the properties of unique proteins and complexes that assemble dynamically in a highly sophisticated manner.
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5
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Blair KM, Mears KS, Taylor JA, Fero J, Jones LA, Gafken PR, Whitney JC, Salama NR. The Helicobacter pylori cell shape promoting protein Csd5 interacts with the cell wall, MurF, and the bacterial cytoskeleton. Mol Microbiol 2018; 110:114-127. [PMID: 30039535 DOI: 10.1111/mmi.14087] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2018] [Indexed: 12/17/2022]
Abstract
Chronic infection with Helicobacter pylori can lead to the development of gastric ulcers and stomach cancers. The helical cell shape of H. pylori promotes stomach colonization. Screens for loss of helical shape have identified several periplasmic peptidoglycan (PG) hydrolases and non-enzymatic putative scaffolding proteins, including Csd5. Both over and under expression of the PG hydrolases perturb helical shape, but the mechanism used to coordinate and localize their enzymatic activities is not known. Using immunoprecipitation and mass spectrometry we identified Csd5 interactions with cytosolic proteins CcmA, a bactofilin required for helical shape, and MurF, a PG precursor synthase, as well as the inner membrane spanning ATP synthase. A combination of Csd5 domain deletions, point mutations, and transmembrane domain chimeras revealed that the N-terminal transmembrane domain promotes MurF, CcmA, and ATP synthase interactions, while the C-terminal SH3 domain mediates PG binding. We conclude that Csd5 promotes helical shape as part of a membrane associated, multi-protein shape complex that includes interactions with the periplasmic cell wall, a PG precursor synthesis enzyme, the bacterial cytoskeleton, and ATP synthase.
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Affiliation(s)
- Kris M Blair
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave, Seattle, WA, 98109, USA.,Molecular and Cellular Biology Ph.D. Program, University of Washington, 1959 NE Pacific Street, HSB T-466, Box 357275, Seattle, WA, 98195-7275, USA
| | - Kevin S Mears
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave, Seattle, WA, 98109, USA
| | - Jennifer A Taylor
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave, Seattle, WA, 98109, USA.,Department of Microbiology, University of Washington, 1705 NE Pacific St., HSB K-343, Box 357735, Seattle, WA, 98195-7735, USA
| | - Jutta Fero
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave, Seattle, WA, 98109, USA
| | - Lisa A Jones
- Proteomics Facility, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., DE-352, Seattle, WA, 98109-1024, USA
| | - Philip R Gafken
- Proteomics Facility, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., DE-352, Seattle, WA, 98109-1024, USA
| | - John C Whitney
- Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, L8S 4K1, Canada
| | - Nina R Salama
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave, Seattle, WA, 98109, USA
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6
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Yuan XY, Wang Y, Wang MY. The type IV secretion system in Helicobacter pylori. Future Microbiol 2018; 13:1041-1054. [PMID: 29927340 DOI: 10.2217/fmb-2018-0038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Helicobacter pylori (H. pylori) has an essential role in the pathogenesis of gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue lymphoma and gastric cancer. The severity of the host inflammatory responses against the bacteria have been straightly associated with a special bacterial virulence factor, the cag pathogenicity island, which is a type IV secretion system (T4SS) to deliver CagA into the host cells. Besides cag-T4SS, the chromosomes of H. pylori can encode another three T4SSs, including comB, tfs3 and tfs4. In this review, we systematically reviewed the four T4SSs of H. pylori and explored their roles in the pathogenesis of gastroduodenal diseases. The information summarized in this review might provide valuable insights into the pathogenic mechanism for H. pylori.
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Affiliation(s)
- Xiao-Yan Yuan
- Department of Central Lab, Weihai Municipal Hospital Affiliated to Dalian Medical University, Weihai, Shandong, 264200, PR China
| | - Ying Wang
- Department of Central Lab, Weihai Municipal Hospital Affiliated to Dalian Medical University, Weihai, Shandong, 264200, PR China
| | - Ming-Yi Wang
- Department of Central Lab, Weihai Municipal Hospital Affiliated to Dalian Medical University, Weihai, Shandong, 264200, PR China
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7
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Backert S, Haas R, Gerhard M, Naumann M. The Helicobacter pylori Type IV Secretion System Encoded by the cag Pathogenicity Island: Architecture, Function, and Signaling. Curr Top Microbiol Immunol 2018. [DOI: 10.1007/978-3-319-75241-9_8] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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8
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Bats SH, Bergé C, Coombs N, Terradot L, Josenhans C. Biochemical characterization of the Helicobacter pylori Cag Type 4 Secretion System protein CagN and its interaction partner CagM. Int J Med Microbiol 2018; 308:425-437. [PMID: 29572102 DOI: 10.1016/j.ijmm.2018.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 02/22/2018] [Accepted: 02/25/2018] [Indexed: 12/26/2022] Open
Abstract
Highly virulent Helicobacter pylori strains contain the cag pathogenicity island (cagPAI). It codes for about 30 proteins forming a type IV secretion system (T4SS) which translocates the pro-inflammatory protein CagA into epithelial host cells. While CagA and various other Cag proteins have been extensively studied, several cagPAI proteins are poorly characterized or of unknown function. CagN (HP0538) is of unknown function but highly conserved in the cagPAI suggesting an important role. cagM (HP0537) is the first gene of the cagMN operon and its product is part of the CagT4SS core complex. Both proteins do not have detectable homologs in other type IV secretion systems. We have characterized the biochemical and structural properties of CagN and CagM and their interaction. We demonstrate by circular dichroism, Multi-Angle Light Scattering (MALS) and small angle X-ray scattering (SAXS) that CagN is a folded, predominantly monomeric protein with an elongated shape in solution. CagM is folded and forms predominantly dimers that are also elongated in solution. We found by various in vivo and in vitro methods that CagN and CagM directly interact with each other. CagM self-interacts stably with a low nanomolar KD and can form stable multimers. Finally, in vivo experiments show that deletion of CagM reduces the amounts of CagN and other outer CagPAI proteins in H. pylori cells.
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Affiliation(s)
- Simon H Bats
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; Max von Pettenkofer Institute, Ludwig Maximilians Universität LMU München, Pettenkoferstraße 9a, 80336 München, Germany
| | - Célia Bergé
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon 1, Institut de Biologie et Chimie des Protéines, 7 Passage du Vercors, 69367 Lyon, Cedex 07, France
| | - Nina Coombs
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; German Center for Infection Research (DZIF), Partner Site Munich, Germany
| | - Laurent Terradot
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon 1, Institut de Biologie et Chimie des Protéines, 7 Passage du Vercors, 69367 Lyon, Cedex 07, France
| | - Christine Josenhans
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover, Germany; Max von Pettenkofer Institute, Ludwig Maximilians Universität LMU München, Pettenkoferstraße 9a, 80336 München, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany; German Center for Infection Research (DZIF), Partner Site Munich, Germany.
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9
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Kumar N, Shariq M, Kumar A, Kumari R, Subbarao N, Tyagi RK, Mukhopadhyay G. Analyzing the role of CagV, a VirB8 homolog of the type IV secretion system of Helicobacter pylori. FEBS Open Bio 2017; 7:915-933. [PMID: 28680806 PMCID: PMC5494299 DOI: 10.1002/2211-5463.12225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/22/2017] [Accepted: 02/24/2017] [Indexed: 12/13/2022] Open
Abstract
The type IV secretion system of Helicobacter pylori (Cag‐T4SS) is composed of ~ 27 components including a VirB8 homolog, CagV. We have characterized CagV and reported that it is an inner membrane protein and, like VirB8, forms a homodimer. Its stability is not dependent on the other Cag components and the absence of cagV affects the stability of only CagI, a protein involved in pilus formation. CagV is not required for the stability and localization of outer membrane subcomplex proteins, but interacts with them through CagX. It also interacts with the inner membrane‐associated components, CagF and CagZ, and is required for the surface localization of CagA. The results of this study might help in deciphering the mechanistic contributions of CagV in the Cag‐T4SS biogenesis and function.
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Affiliation(s)
- Navin Kumar
- Special Centre for Molecular Medicine Jawaharlal Nehru University New Delhi India.,Present address: School of Biotechnology Gautam Buddha University Yamuna Expressway Greater Noida Gautam Budh Nagar Uttar Pradesh India
| | - Mohd Shariq
- Special Centre for Molecular Medicine Jawaharlal Nehru University New Delhi India.,Present address: School of Life Sciences Jawaharlal Nehru University New Delhi India
| | - Amarjeet Kumar
- School of Computational and Integrative Sciences Jawaharlal Nehru University New Delhi India
| | - Rajesh Kumari
- Special Centre for Molecular Medicine Jawaharlal Nehru University New Delhi India
| | - Naidu Subbarao
- School of Computational and Integrative Sciences Jawaharlal Nehru University New Delhi India
| | - Rakesh K Tyagi
- Special Centre for Molecular Medicine Jawaharlal Nehru University New Delhi India
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10
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Merino E, Flores-Encarnación M, Aguilar-Gutiérrez GR. Functional interaction and structural characteristics of unique components of Helicobacter pylori T4SS. FEBS J 2017; 284:3540-3549. [PMID: 28470874 DOI: 10.1111/febs.14092] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 03/14/2017] [Accepted: 04/26/2017] [Indexed: 12/25/2022]
Abstract
The Helicobacter pylori infection of the human gastric mucosa causes chronic active gastritis and peptic ulcers and is associated with the development of gastric cancer. Epidemiological studies show that these gastric diseases are related to virulent H. pylori strains that harbor the cytotoxin-associated gene pathogenicity island (cag PAI). The cag PAI is a DNA insertion in the H. pylori chromosome that encodes ~ 27 proteins, including the oncoprotein CagA. Approximately 20 of these proteins have been designated as cag type IV secretion system (T4SS) components. However, only 11 of these proteins share function, structure, and/or sequence similarities with the prototypical VirB/VirD4 T4SS of Agrobacterium tumefaciens. The VirB/VirD4 orthologs of the cag T4SS of H. pylori are required for CagA translocation and stimulate the gastric epithelial cells to produce and secrete interleukin-8 (IL-8). The cag PAI encodes eight additional proteins, such as Cag3 (Cagδ/HP0522), CagM (Cag16/HP0537), CagU (Cag11/HP0531), CagI (Cag19/HP0540), and CagH (Cag20/HP0541), which are also required for the translocation of CagA and IL-8 secretion, meanwhile CagF (Cag22/HP0543), CagG (Cag21/HP0542), and CagZ (Cag6/HP0526) are just required for the translocation of CagA. However, relatively little is known about their functions and structural organization because they exhibit a nondetectable sequence similarity with T4SS components in the current databases. In this review, we conducted an exhaustive analysis of the literature to present the biochemistry, putative role, localization, and interactions of each of these eight additional cag T4SS components.
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Affiliation(s)
- Enrique Merino
- Enrique Merino, Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Marcos Flores-Encarnación
- Marcos Flores-Encarnación, Laboratorio de Microbiología Molecular y Celular, Facultad de Medicina, Benemérita Universidad Autónoma de Puebla, Puebla, México
| | - Germán Rubén Aguilar-Gutiérrez
- Germán Rubén Aguilar-Gutiérrez, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México
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11
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Zhang J, Fan F, Zhao Y, Sun L, Liu Y, Keegan RM, Isupov MN, Wu Y. Crystal structure of the type IV secretion system component CagX from Helicobacter pylori. Acta Crystallogr F Struct Biol Commun 2017; 73:167-173. [PMID: 28291753 PMCID: PMC5349311 DOI: 10.1107/s2053230x17001376] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/26/2017] [Indexed: 12/28/2022] Open
Abstract
Helicobacter pylori, a Gram-negative bacterial pathogen prevalent in the human population, is the causative agent of severe gastric diseases. An H. pylori type IV secretion (T4S) system encoded by the cytotoxin-associated gene pathogenicity island (cagPAI) is responsible for communication with host cells. As a component of the cagPAI T4S system core complex, CagX plays an important role in virulence-protein translocation into the host cells. In this work, the crystal structure of the C-terminal domain of CagX (CagXct), which is a homologue of the VirB9 protein from the VirB/D4 T4S system, is presented. CagXct is only the second three-dimensional structure to be elucidated of a VirB9-like protein. Another homologue, TraO, which is encoded on the Escherichia coli conjugative plasmid pKM101, shares only 19% sequence identity with CagXct; however, there is a remarkable similarity in tertiary structure between these two β-sandwich protein domains. Most of the residues that are conserved between CagXct and TraO are located within the protein core and appear to be responsible for the preservation of this domain fold. The studies presented here will contribute to our understanding of different bacterial T4S systems.
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Affiliation(s)
- Jin Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
| | - Fei Fan
- Fujian Health College, Fuzhou 350101, People’s Republic of China
| | - Yanhe Zhao
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
| | - Lifang Sun
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
| | - Yadan Liu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
| | - Ronan M. Keegan
- CCP4, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0FA, England
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, England
| | - Michail N. Isupov
- The Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, England
| | - Yunkun Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, People’s Republic of China
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12
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Kumari R, Shariq M, Kumar N, Mukhopadhyay G. Biochemical characterization of theHelicobacter pyloriCag-type IV secretion system unique component CagU. FEBS Lett 2017; 591:500-512. [DOI: 10.1002/1873-3468.12564] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 12/16/2016] [Accepted: 01/10/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Rajesh Kumari
- Special Centre for Molecular Medicine; Jawaharlal Nehru University; New Delhi India
| | - Mohd Shariq
- Special Centre for Molecular Medicine; Jawaharlal Nehru University; New Delhi India
- School of Life Sciences; Jawaharlal Nehru University; New Delhi India
| | - Navin Kumar
- Special Centre for Molecular Medicine; Jawaharlal Nehru University; New Delhi India
- School of Biotechnology; Gautam Buddha University; Uttar Pradesh India
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13
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Smart J, Fouillen A, Casu B, Nanci A, Baron C. Cag-delta (Cag3) protein from theHelicobacter pylori26695cagtype IV secretion system forms ring-like supramolecular assemblies. FEMS Microbiol Lett 2016; 364:fnw280. [DOI: 10.1093/femsle/fnw280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/20/2016] [Accepted: 12/13/2016] [Indexed: 12/11/2022] Open
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Backert S, Tegtmeyer N, Fischer W. Composition, structure and function of the Helicobacter pylori cag pathogenicity island encoded type IV secretion system. Future Microbiol 2016; 10:955-65. [PMID: 26059619 DOI: 10.2217/fmb.15.32] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Many Gram-negative pathogens harbor type IV secretion systems (T4SS) that translocate bacterial virulence factors into host cells to hijack cellular processes. The pathology of the gastric pathogen Helicobacter pylori strongly depends on a T4SS encoded by the cag pathogenicity island. This T4SS forms a needle-like pilus, and its assembly is accomplished by multiple protein-protein interactions and various pilus-associated factors that bind to integrins followed by delivery of the CagA oncoprotein into gastric epithelial cells. Recent studies revealed the crystal structures of six T4SS proteins and pilus formation is modulated by iron and zinc availability. All these T4SS interactions are crucial for deregulating host signaling events and disease progression. New developments in T4SS functions and their importance for pathogenesis are discussed.
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Affiliation(s)
- Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany
| | - Wolfgang Fischer
- Max von Pettenkofer-Institute for Hygiene & Medical Microbiology, Ludwig Maximilians-University, D-80336 Munich, Germany
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15
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Pérez-Figueroa E, Torres J, Sánchez-Zauco N, Contreras-Ramos A, Alvarez-Arellano L, Maldonado-Bernal C. Activation of NLRP3 inflammasome in human neutrophils by Helicobacter pylori infection. Innate Immun 2016; 22:103-112. [DOI: 10.1177/1753425915619475] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
TLRs and NLRs participate in the immune system recognition of Helicobacter pylori. However, little is known about the mechanisms leading to inflammasome activation by H. pylori and if NLRs in neutrophils are involved in the process. We studied how NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome components are involved in IL-1β maturation in human neutrophils in response to the infection and if they are dependent on T4SS (type IV secretion system) and TLRs. Human neutrophils were cultured and infected with the 26695 or the VirD4− H. pylori strains; the IL-1β concentration was analyzed by ELISA, and we also evaluated the activation of TLRs 2 and 4. The infection of neutrophils with both strains of H. pylori induced production of IL-1β and expression of the NLRP3 inflammasome components such as apoptosis-associated speck-like protein with CARD domain and NLRP3 protein. The infection also increased the activity of caspase-1, which is required for the maturation of IL-1β. Our study shows, for the first time, that H. pylori infection induces the expression and activation of components of NLRP3 inflammasomes in human neutrophils and that the activation is independent of a functional T4SS and TLR2 and TLR4.
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Affiliation(s)
- Erandi Pérez-Figueroa
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, México City, México
- Unidad de Investigación Médica en Enfermedades Infecciosas, Hospital de Pediatría, CMN SXXI, IMSS, México City, México
| | - Javier Torres
- Unidad de Investigación Médica en Enfermedades Infecciosas, Hospital de Pediatría, CMN SXXI, IMSS, México City, México
| | - Norma Sánchez-Zauco
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, México City, México
- Unidad de Investigación Médica en Enfermedades Infecciosas, Hospital de Pediatría, CMN SXXI, IMSS, México City, México
| | - Alejandra Contreras-Ramos
- Laboratorio de Biología del Desarrollo, Hospital Infantil de México Federico Gómez, México City, México
| | | | - Carmen Maldonado-Bernal
- Laboratorio de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, México City, México
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16
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Molecular and Structural Analysis of the Helicobacter pylori cag Type IV Secretion System Core Complex. mBio 2016; 7:e02001-15. [PMID: 26758182 PMCID: PMC4725015 DOI: 10.1128/mbio.02001-15] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bacterial type IV secretion systems (T4SSs) can function to export or import DNA, and can deliver effector proteins into a wide range of target cells. Relatively little is known about the structural organization of T4SSs that secrete effector proteins. In this report, we describe the isolation and analysis of a membrane-spanning core complex from the Helicobacter pylori cag T4SS, which has an important role in the pathogenesis of gastric cancer. We show that this complex contains five H. pylori proteins, CagM, CagT, Cag3, CagX, and CagY, each of which is required for cag T4SS activity. CagX and CagY are orthologous to the VirB9 and VirB10 components of T4SSs in other bacterial species, and the other three Cag proteins are unique to H. pylori. Negative stain single-particle electron microscopy revealed complexes 41 nm in diameter, characterized by a 19-nm-diameter central ring linked to an outer ring by spoke-like linkers. Incomplete complexes formed by Δcag3 or ΔcagT mutants retain the 19-nm-diameter ring but lack an organized outer ring. Immunogold labeling studies confirm that Cag3 is a peripheral component of the complex. The cag T4SS core complex has an overall diameter and structural organization that differ considerably from the corresponding features of conjugative T4SSs. These results highlight specialized features of the H. pylori cag T4SS that are optimized for function in the human gastric mucosal environment. Type IV secretion systems (T4SSs) are versatile macromolecular machines that are present in many bacterial species. In this study, we investigated a T4SS found in the bacterium Helicobacter pylori. H. pylori is an important cause of stomach cancer, and the H. pylori T4SS contributes to cancer pathogenesis by mediating entry of CagA (an effector protein regarded as a “bacterial oncoprotein”) into gastric epithelial cells. We isolated and analyzed the membrane-spanning core complex of the H. pylori T4SS and showed that it contains unique proteins unrelated to components of T4SSs in other bacterial species. These results constitute the first structural analysis of the core complex from this important secretion system.
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17
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Shariq M, Kumar N, Kumari R, Kumar A, Subbarao N, Mukhopadhyay G. Biochemical Analysis of CagE: A VirB4 Homologue of Helicobacter pylori Cag-T4SS. PLoS One 2015; 10:e0142606. [PMID: 26565397 PMCID: PMC4643968 DOI: 10.1371/journal.pone.0142606] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 10/23/2015] [Indexed: 12/30/2022] Open
Abstract
Helicobacter pylori are among the most successful human pathogens that harbour a distinct genomic segment called cag Pathogenicity Island (cag-PAI). This genomic segment codes for a type IV secretion system (Cag-T4SS) related to the prototypical VirB/D4 system of Agrobacterium tumefaciens (Ag), a plant pathogen. Some of the components of Cag-T4SS share homology to that of VirB proteins including putative energy providing CagE (HP0544), the largest VirB4 homologue. In Ag, VirB4 is required for the assembly of the system, substrate translocation and pilus formation, however, very little is known about CagE. Here we have characterised the protein biochemically, genetically, and microscopically and report that CagE is an inner membrane associated active NTPase and has multiple interacting partners including the inner membrane proteins CagV and Cagβ. Through CagV it is connected to the outer membrane sub-complex proteins. Stability of CagE is not dependent on several of the cag-PAI proteins tested. However, localisation and stability of the pilus associated CagI, CagL and surface associated CagH are affected in its absence. Stability of the inner membrane associated energetic component Cagβ, a VirD4 homologue seems to be partially affected in its absence. Additionally, CagA failed to cross the membrane barriers in its absence and no IL-8 induction is observed under infection condition. These results thus suggest the importance of CagE in Cag-T4SS functions. In future it may help in deciphering the mechanism of substrate translocation by the system.
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Affiliation(s)
- Mohd Shariq
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
- * E-mail: (MS); (GM)
| | - Navin Kumar
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Rajesh Kumari
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Amarjeet Kumar
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Naidu Subbarao
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Gauranga Mukhopadhyay
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- * E-mail: (MS); (GM)
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18
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Chan ACK, Blair KM, Liu Y, Frirdich E, Gaynor EC, Tanner ME, Salama NR, Murphy MEP. Helical shape of Helicobacter pylori requires an atypical glutamine as a zinc ligand in the carboxypeptidase Csd4. J Biol Chem 2014; 290:3622-38. [PMID: 25505267 DOI: 10.1074/jbc.m114.624734] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Peptidoglycan modifying carboxypeptidases (CPs) are important determinants of bacterial cell shape. Here, we report crystal structures of Csd4, a three-domain protein from the human gastric pathogen Helicobacter pylori. The catalytic zinc in Csd4 is coordinated by a rare His-Glu-Gln configuration that is conserved among most Csd4 homologs, which form a distinct subfamily of CPs. Substitution of the glutamine to histidine, the residue found in prototypical zinc carboxypeptidases, resulted in decreased enzyme activity and inhibition by phosphate. Expression of the histidine variant at the native locus in a H. pylori csd4 deletion strain did not restore the wild-type helical morphology. Biochemical assays show that Csd4 can cleave a tripeptide peptidoglycan substrate analog to release m-DAP. Structures of Csd4 with this substrate analog or product bound at the active site reveal determinants of peptidoglycan specificity and the mechanism to cleave an isopeptide bond to release m-DAP. Our data suggest that Csd4 is the archetype of a new CP subfamily with a domain scheme that differs from this large family of peptide-cleaving enzymes.
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Affiliation(s)
- Anson C K Chan
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Kris M Blair
- the Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, the Program in Molecular and Cellular Biology, University of Washington, Seattle, Washington 98195, and
| | - Yanjie Liu
- the Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Emilisa Frirdich
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Erin C Gaynor
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Martin E Tanner
- the Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Nina R Salama
- the Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, the Program in Molecular and Cellular Biology, University of Washington, Seattle, Washington 98195, and
| | - Michael E P Murphy
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada,
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19
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DeMaster LK, Rose TM. A critical Sp1 element in the rhesus rhadinovirus (RRV) Rta promoter confers high-level activity that correlates with cellular permissivity for viral replication. Virology 2013; 448:196-209. [PMID: 24314650 DOI: 10.1016/j.virol.2013.10.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 08/25/2013] [Accepted: 10/08/2013] [Indexed: 10/26/2022]
Abstract
KSHV establishes characteristic latent infections in vitro, while RRV, a related macaque rhadinovirus, establishes characteristic permissive infections with virus replication. We identified cells that are not permissive for RRV replication and recapitulate the latent KSHV infection and reactivation processes. The RRV replication and transactivator (Rta) promoter was characterized in permissive and non-permissive cells and compared to the KSHV Rta promoter. Both promoters contained a critical Sp1 element, had equivalent activities in different cell types, and were inhibited by LANA. RRV and KSHV infections were non-permissive in cells with low Rta promoter activity. While RRV infections were permissive in cells with high basal promoter activity, KSHV infections remained non-permissive. Our studies suggest that RRV lacks the Rta-inducible LANA promoter that is responsible for LANA inhibition of the KSHV Rta promoter and induction of latency during KSHV infection. Instead, the outcome of RRV infection is determined by host factors, such as Sp1.
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Affiliation(s)
- Laura K DeMaster
- Department of Global Health, University of Washington, Seattle, WA 98195, USA; Center for Childhood Infections and Prematurity Research, Seattle Children's Research Institute, Seattle, WA 98101, USA.
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20
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Sycuro LK, Rule CS, Petersen TW, Wyckoff TJ, Sessler T, Nagarkar DB, Khalid F, Pincus Z, Biboy J, Vollmer W, Salama NR. Flow cytometry-based enrichment for cell shape mutants identifies multiple genes that influence Helicobacter pylori morphology. Mol Microbiol 2013; 90:869-83. [PMID: 24112477 PMCID: PMC3844677 DOI: 10.1111/mmi.12405] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2013] [Indexed: 12/17/2022]
Abstract
The helical cell shape of Helicobacter pylori is highly conserved and contributes to its ability to swim through and colonize the viscous gastric mucus layer. A multi-faceted peptidoglycan (PG) modification programme involving four recently characterized peptidases and two accessory proteins is essential for maintaining H. pylori's helicity. To expedite identification of additional shape-determining genes, we employed flow cytometry with fluorescence-activated cell sorting (FACS) to enrich a transposon library for bacterial cells with altered light scattering profiles that correlate with perturbed cell morphology. After a single round of sorting, 15% of our clones exhibited a stable cell shape defect, reflecting 37-fold enrichment. Sorted clones with straight rod morphology contained insertions in known PG peptidases, as well as an insertion in csd6, which we demonstrated has ld-carboxypeptidase activity and cleaves monomeric tetrapeptides in the PG sacculus, yielding tripeptides. Other mutants had only slight changes in helicity due to insertions in genes encoding MviN/MurJ, a protein possibly involved in initiating PG synthesis, and the hypothetical protein HPG27_782. Our findings demonstrate FACS robustly detects perturbations of bacterial cell shape and identify additional PG peptide modifications associated with helical cell shape in H. pylori.
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Affiliation(s)
- Laura K Sycuro
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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21
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Kumar N, Shariq M, Kumari R, Tyagi RK, Mukhopadhyay G. Cag type IV secretion system: CagI independent bacterial surface localization of CagA. PLoS One 2013; 8:e74620. [PMID: 24040297 PMCID: PMC3769253 DOI: 10.1371/journal.pone.0074620] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/05/2013] [Indexed: 12/14/2022] Open
Abstract
Helicobacter pylori Cag type IV secretion system (Cag-T4SS) is a multi-component transporter of oncoprotein CagA across the bacterial membranes into the host epithelial cells. To understand the role of unique Cag-T4SS component CagI in CagA translocation, we have characterized it by biochemical and microscopic approaches. We observed that CagI is a predominantly membrane attached periplasmic protein partially exposed to the bacterial surface especially on the pili. The association of the protein with membrane appeared to be loose as it could be easily recovered in soluble fraction. We documented that the stability of the protein is dependent on several key components of the secretion system and it has multiple interacting partners including a non-cag-PAI protein HP1489. Translocation of CagA across the bacterial membranes to cell surface is CagI-independent process. The observations made herein are expected to assist in providing an insight into the substrate translocation by the Cag-T4SS system and Helicobacter pylori pathogenesis.
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Affiliation(s)
- Navin Kumar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- * E-mail: (GM); (NK)
| | - Mohd Shariq
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Rajesh Kumari
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Rakesh K. Tyagi
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Gauranga Mukhopadhyay
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- * E-mail: (GM); (NK)
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22
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Sánchez-Zauco NA, Torres J, Pérez-Figueroa GE, Álvarez-Arellano L, Camorlinga-Ponce M, Gómez A, Giono-Cerezo S, Maldonado-Bernal C. Impact of cagPAI and T4SS on the inflammatory response of human neutrophils to Helicobacter pylori infection. PLoS One 2013; 8:e64623. [PMID: 23755130 PMCID: PMC3670914 DOI: 10.1371/journal.pone.0064623] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 04/17/2013] [Indexed: 12/16/2022] Open
Abstract
Helicobacter pylori contains a pathogenicity island, cagPAI, with genes homologous to components of the type IV secretion system (T4SS) of Agrobacterium tumefaciens. The T4SS components assemble a structure that transfers CagA protein and peptidoglycan into host epithelial cells, causing the increased release of interleukin 8 (IL8) from the cells. The Toll-like receptors on neutrophils recognize H. pylori, initiating signaling pathways that enhance the activation of NF-κB. However, the roles of cagPAI and T4SS in the inflammatory response of neutrophils are unknown. We evaluated the participation of cagPAI and T4SS in the response of human neutrophils to H. pylori infection. Neutrophils were isolated from the blood of healthy donors and infected with H. pylori cagPAI(+), cagPAI(-), and cagPAI mutant strains virB4 (-) and virD4 (-). Whereas cagPAI(+) strain 26695 induced the greatest IL8 production, a proinflammatory response, cagPAI(-) strain 8822 induced the greatest IL10 production, an anti-inflammatory response. In contrast, the virB4 (-) and virD4 (-) mutant strains produced significantly more of the two proinflammatory cytokines IL1β and tumor necrosis factor αthan the cagPAI(+) strain 26695. We observed that H. pylori downregulated the expression of TLRs 2 and 5 but upregulated TLR9 expression in a cagPAI and T4SS-independent manner. These results show for the first time that the response of human neutrophils to H. pylori may vary from a pro-inflammatory to an anti-inflammatory response, depending on cagPAI and the integrity of T4SS.
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Affiliation(s)
- Norma Angélica Sánchez-Zauco
- Unidad de Investigación en Enfermedades Oncológicas, Hospital Infantil de México Federico Gómez, SS. Mexico City, México
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
- Laboratorio de Bacteriología Médica, Escuela Nacional de Ciencias Biológicas-IPN, Mexico City, México
| | - Javier Torres
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
| | - Gloria Erandi Pérez-Figueroa
- Unidad de Investigación en Enfermedades Oncológicas, Hospital Infantil de México Federico Gómez, SS. Mexico City, México
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
| | - Lourdes Álvarez-Arellano
- Laboratorio de Neuroinmunología, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, UNAM. Cuernavaca, Morelos, México
| | - Margarita Camorlinga-Ponce
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
| | - Alejandro Gómez
- Unidad de Investigación en Enfermedades Infecciosas, Centro Médico Nacional Siglo XXI, IMSS. Mexico City, México
| | - Silvia Giono-Cerezo
- Laboratorio de Bacteriología Médica, Escuela Nacional de Ciencias Biológicas-IPN, Mexico City, México
| | - Carmen Maldonado-Bernal
- Unidad de Investigación en Enfermedades Oncológicas, Hospital Infantil de México Federico Gómez, SS. Mexico City, México
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23
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Zechner EL, Lang S, Schildbach JF. Assembly and mechanisms of bacterial type IV secretion machines. Philos Trans R Soc Lond B Biol Sci 2012; 367:1073-87. [PMID: 22411979 PMCID: PMC3297438 DOI: 10.1098/rstb.2011.0207] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Type IV secretion occurs across a wide range of prokaryotic cell envelopes: Gram-negative, Gram-positive, cell wall-less bacteria and some archaea. This diversity is reflected in the heterogeneity of components that constitute the secretion machines. Macromolecules are secreted in an ATP-dependent process using an envelope-spanning multi-protein channel. Similar to the type III systems, this apparatus extends beyond the cell surface as a pilus structure important for direct contact and penetration of the recipient cell surface. Type IV systems are remarkably versatile in that they mobilize a broad range of substrates, including single proteins, protein complexes, DNA and nucleoprotein complexes, across the cell envelope. These machines have broad clinical significance not only for delivering bacterial toxins or effector proteins directly into targeted host cells, but also for direct involvement in phenomena such as biofilm formation and the rapid horizontal spread of antibiotic resistance genes among the microbial community.
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Affiliation(s)
- Ellen L Zechner
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/I, Graz 8010, Austria.
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24
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Talarico S, Whitefield SE, Fero J, Haas R, Salama NR. Regulation of Helicobacter pylori adherence by gene conversion. Mol Microbiol 2012; 84:1050-61. [PMID: 22519812 DOI: 10.1111/j.1365-2958.2012.08073.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Genetic diversification of Helicobacter pylori adhesin genes may allow adaptation of adherence properties to facilitate persistence despite host defences. The sabA gene encodes an adhesin that binds sialyl-Lewis antigens on inflamed gastric tissue. We found variability in the copy number and locus of the sabA gene and the closely related sabB and omp27 genes due to gene conversion among 51 North American paediatric H. pylori strains. We determined that sabB to sabA gene conversion is predominantly the result of intra-genomic recombination and RecA, RecG and AddA influence the rate at which it occurs. Although all clinical strains had at least one sabA gene copy, sabA and sabB were lost due to gene conversion at similar rates in vitro, suggesting host selection to maintain the sabA gene. sabA gene duplication resulted in increased SabA protein production and increased adherence to sialyl-Lewis antigens and mouse gastric tissue. In conclusion, gene conversion is a mechanism for H. pylori to regulate sabA expression level and adherence.
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Affiliation(s)
- Sarah Talarico
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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25
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Pham KT, Weiss E, Jiménez Soto LF, Breithaupt U, Haas R, Fischer W. CagI is an essential component of the Helicobacter pylori Cag type IV secretion system and forms a complex with CagL. PLoS One 2012; 7:e35341. [PMID: 22493745 PMCID: PMC3320882 DOI: 10.1371/journal.pone.0035341] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 03/15/2012] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori, the causative agent of type B gastritis, peptic ulcers, gastric adenocarcinoma and MALT lymphoma, uses the Cag type IV secretion system to induce a strong proinflammatory response in the gastric mucosa and to inject its effector protein CagA into gastric cells. CagA translocation results in altered host cell gene expression profiles and cytoskeletal rearrangements, and it is considered as a major bacterial virulence trait. Recently, it has been shown that binding of the type IV secretion apparatus to integrin receptors on target cells is a crucial step in the translocation process. Several bacterial proteins, including the Cag-specific components CagL and CagI, have been involved in this interaction. Here, we have examined the localization and interactions of CagI in the bacterial cell. Since the cagI gene overlaps and is co-transcribed with the cagL gene, the role of CagI for type IV secretion system function has been difficult to assess, and conflicting results have been reported regarding its involvement in the proinflammatory response. Using a marker-free gene deletion approach and genetic complementation, we show now that CagI is an essential component of the Cag type IV secretion apparatus for both CagA translocation and interleukin-8 induction. CagI is distributed over soluble and membrane-associated pools and seems to be partly surface-exposed. Deletion of several genes encoding essential Cag components has an impact on protein levels of CagI and CagL, suggesting that both proteins require partial assembly of the secretion apparatus. Finally, we show by co-immunoprecipitation that CagI and CagL interact with each other. Taken together, our results indicate that CagI and CagL form a functional complex which is formed at a late stage of secretion apparatus assembly.
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Affiliation(s)
- Kieu Thuy Pham
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität, München, Germany
| | - Evelyn Weiss
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität, München, Germany
| | - Luisa F. Jiménez Soto
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität, München, Germany
| | - Ute Breithaupt
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität, München, Germany
| | - Rainer Haas
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität, München, Germany
| | - Wolfgang Fischer
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität, München, Germany
- * E-mail:
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Sycuro LK, Wyckoff TJ, Biboy J, Born P, Pincus Z, Vollmer W, Salama NR. Multiple peptidoglycan modification networks modulate Helicobacter pylori's cell shape, motility, and colonization potential. PLoS Pathog 2012; 8:e1002603. [PMID: 22457625 PMCID: PMC3310797 DOI: 10.1371/journal.ppat.1002603] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 01/05/2012] [Indexed: 12/14/2022] Open
Abstract
Helical cell shape of the gastric pathogen Helicobacter pylori has been suggested to promote virulence through viscosity-dependent enhancement of swimming velocity. However, H. pylori csd1 mutants, which are curved but lack helical twist, show normal velocity in viscous polymer solutions and the reason for their deficiency in stomach colonization has remained unclear. Characterization of new rod shaped mutants identified Csd4, a DL-carboxypeptidase of peptidoglycan (PG) tripeptide monomers and Csd5, a putative scaffolding protein. Morphological and biochemical studies indicated Csd4 tripeptide cleavage and Csd1 crosslinking relaxation modify the PG sacculus through independent networks that coordinately generate helical shape. csd4 mutants show attenuation of stomach colonization, but no change in proinflammatory cytokine induction, despite four-fold higher levels of Nod1-agonist tripeptides in the PG sacculus. Motility analysis of similarly shaped mutants bearing distinct alterations in PG modifications revealed deficits associated with shape, but only in gel-like media and not viscous solutions. As gastric mucus displays viscoelastic gel-like properties, our results suggest enhanced penetration of the mucus barrier underlies the fitness advantage conferred by H. pylori's characteristic shape.
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Affiliation(s)
- Laura K. Sycuro
- Molecular and Cellular Biology Graduate Program, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Timna J. Wyckoff
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Division of Science and Mathematics, University of Minnesota, Morris, Minnesota, United States of America
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Petra Born
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Zachary Pincus
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nina R. Salama
- Molecular and Cellular Biology Graduate Program, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
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Shaffer CL, Gaddy JA, Loh JT, Johnson EM, Hill S, Hennig EE, McClain MS, McDonald WH, Cover TL. Helicobacter pylori exploits a unique repertoire of type IV secretion system components for pilus assembly at the bacteria-host cell interface. PLoS Pathog 2011; 7:e1002237. [PMID: 21909278 PMCID: PMC3164655 DOI: 10.1371/journal.ppat.1002237] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 07/10/2011] [Indexed: 12/27/2022] Open
Abstract
Colonization of the human stomach by Helicobacter pylori is an important risk factor for development of gastric cancer. The H. pylori cag pathogenicity island (cag PAI) encodes components of a type IV secretion system (T4SS) that translocates the bacterial oncoprotein CagA into gastric epithelial cells, and CagL is a specialized component of the cag T4SS that binds the host receptor α5β1 integrin. Here, we utilized a mass spectrometry-based approach to reveal co-purification of CagL, CagI (another integrin-binding protein), and CagH (a protein with weak sequence similarity to CagL). These three proteins are encoded by contiguous genes in the cag PAI, and are detectable on the bacterial surface. All three proteins are required for CagA translocation into host cells and H. pylori-induced IL-8 secretion by gastric epithelial cells; however, these proteins are not homologous to components of T4SSs in other bacterial species. Scanning electron microscopy analysis reveals that these proteins are involved in the formation of pili at the interface between H. pylori and gastric epithelial cells. ΔcagI and ΔcagL mutant strains fail to form pili, whereas a ΔcagH mutant strain exhibits a hyperpiliated phenotype and produces pili that are elongated and thickened compared to those of the wild-type strain. This suggests that pilus dimensions are regulated by CagH. A conserved C-terminal hexapeptide motif is present in CagH, CagI, and CagL. Deletion of these motifs results in abrogation of CagA translocation and IL-8 induction, and the C-terminal motifs of CagI and CagL are required for formation of pili. In summary, these results indicate that CagH, CagI, and CagL are components of a T4SS subassembly involved in pilus biogenesis, and highlight the important role played by unique constituents of the H. pylori cag T4SS. Helicobacter pylori persistently colonizes the stomach in approximately half of the human population. People who are infected with H. pylori strains harboring the cag pathogenicity island (PAI) have an increased risk of developing gastric cancer. The cag PAI encodes a type IV secretion system (T4SS) that is utilized by the bacteria to inject the bacterial oncoprotein CagA into gastric epithelial cells. Related T4SSs found in several other bacteria have been studied in detail, but thus far there has been very little study of the H. pylori cag T4SS. Here, we utilized a mass spectrometry-based approach to reveal co-purification of three constituents of the H. pylori T4SS (CagH, CagI, and CagL) that lack homology to components of T4SSs in other bacterial species. These proteins are essential for CagA translocation into host cells, and scanning electron microscope studies reveal that the proteins are involved in the formation of pili at the bacterial-host cell interface. A conserved C-terminal motif present in CagH, CagI, and CagL is essential for functionality of the T4SS. This study highlights the important role played by unique constituents of the H. pylori cag T4SS, and illustrates the marked variation that exists among bacterial T4SSs.
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Affiliation(s)
- Carrie L. Shaffer
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Jennifer A. Gaddy
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - John T. Loh
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Elizabeth M. Johnson
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Salisha Hill
- Proteomics Laboratory, Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Ewa E. Hennig
- Department of Gastroenterology and Hepatology, Medical Center for Postgraduate Education, and Department of Oncological Genetics, Cancer Center Institute, Warsaw, Poland
| | - Mark S. McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - W. Hayes McDonald
- Proteomics Laboratory, Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Timothy L. Cover
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
- * E-mail:
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Schuelein R, Everingham P, Kwok T. Integrin-mediated type IV secretion by Helicobacter: what makes it tick? Trends Microbiol 2011; 19:211-6. [PMID: 21371889 DOI: 10.1016/j.tim.2011.01.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 01/18/2011] [Accepted: 01/27/2011] [Indexed: 12/13/2022]
Abstract
Helicobacter pylori (Hp) employs a multi-component type IV secretion system (T4SS) to secrete the effector protein CagA into the cytosol of infected host cells. A longstanding challenge has been to identify the host cell receptor(s) involved. Two recent studies have independently unveiled human β(1) integrin as the receptor but are divided over which T4SS proteins bind to β(1) integrin. Here we revisit the two models in light of previous findings and recent progress in the field. More concerted efforts are required to fully understand the complex T4SS mechanisms that underpin Hp pathogenesis.
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Affiliation(s)
- Ralf Schuelein
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Australia
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29
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Microorganismos y cáncer: evidencias científicas y nuevas hipótesis. Cir Esp 2011; 89:136-44. [DOI: 10.1016/j.ciresp.2010.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 08/03/2010] [Accepted: 08/03/2010] [Indexed: 01/15/2023]
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Cendron L, Zanotti G. Structural and functional aspects of unique type IV secretory components in the Helicobacter pylori cag-pathogenicity island. FEBS J 2011; 278:1223-31. [PMID: 21284804 DOI: 10.1111/j.1742-4658.2011.08038.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Helicobacter pylori cytotoxin-associated gene-pathogenicity island (cagPAI) is responsible for the secretion of the CagA effector through a type IV secretion system (T4SS) apparatus, as well as of peptidoglycan and possibly other not yet identified factors. Twenty-nine different polypeptide chains are encoded by this cluster of genes, although only some of them show a significant similarity with the constitutive elements of well characterized secretion systems from other bacteria. The other cagPAI components represent almost unique proteins in this scenario. The majority of the T4SS include approximately fifteen components, taking into account either the transmembrane complex subunits, ATPases or substrate factors. The composition of the cagPAI is very complex: it includes proteins most likely involved at different levels in the pilus assembly, stabilization and processing of secreted substrate, as well as regulatory particles possibly involved in the control of the entire apparatus. Despite recent findings with respect to components that play a role in the interaction with the host cell, the function of several cagPAI proteins remains unclear or unknown. This is particularly true for those that represent unique members with no clear similarity to those of other T4SS and no obvious evidence of involvement in the secretion of CagA or induction of pro-inflammatory responses. We summarize what is known about these accessory components, both from a molecular and structural point of view, as well as their putative physiological role.
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Affiliation(s)
- Laura Cendron
- Department of Biological Chemistry, University of Padua, Padua, Italy
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31
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Abstract
Type IV secretion systems (T4SS) are macromolecular assemblies used by bacteria to transport material across their membranes. T4SS are generally composed of a set of twelve proteins (VirB1-11 and VirD4). This represents a dynamic machine powered by three ATPases. T4SS are widespread in pathogenic bacteria where they are often used to deliver effectors into host cells. For example, the human pathogen Helicobacter pylori encodes a T4SS, the Cag-T4SS, which mediates the injection of the toxin CagA. We review the progress made in the past decade in our understanding of T4SS architecture. We translate this new knowledge to derive an understanding of the structure of the H. pylori Cag system, and use recent protein-protein interaction data to refine this model.
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Affiliation(s)
- Laurent Terradot
- Institut de Biologie et Chimie des Protéines, Biologie Structurale des Complexes Macromoléculaires Bactériens, UMR 5086 CNRS Université de Lyon, Lyon, France.
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32
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Fischer W. Assembly and molecular mode of action of the Helicobacter pylori Cag type IV secretion apparatus. FEBS J 2011; 278:1203-12. [PMID: 21352490 DOI: 10.1111/j.1742-4658.2011.08036.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bacterial type IV secretion systems (T4SS) form supramolecular protein complexes that are capable of transporting DNA or protein substrates across the bacterial cell envelope and, in many cases, also across eukaryotic target cell membranes. Because of these characteristics, they are often used by pathogenic bacteria for the injection of host cell-modulating virulence factors. One example is the human pathogen Helicobacter pylori, which uses the Cag-T4SS to induce a pro-inflammatory response and multiple cytoskeletal and gene regulatory effects in gastric epithelial cells. Work in recent years has shown that the Cag-T4SS exhibits marked differences in relation to other systems, both with respect to the composition of its secretion apparatus and the molecular details of its secretion mechanisms. This review describes the molecular properties of the Cag-T4SS and compares these with prototypical systems of this family of protein transporters.
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Affiliation(s)
- Wolfgang Fischer
- Max von Pettenkofer-Institut, Ludwig-Maximilians-Universität, München, Germany.
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Humbert O, Dorer MS, Salama NR. Characterization of Helicobacter pylori factors that control transformation frequency and integration length during inter-strain DNA recombination. Mol Microbiol 2010; 79:387-401. [PMID: 21219459 DOI: 10.1111/j.1365-2958.2010.07456.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Helicobacter pylori is a genetically diverse bacterial species, owing in part to its natural competence for DNA uptake that facilitates recombination between strains. Inter-strain DNA recombination occurs during human infection and the H. pylori genome is in linkage equilibrium worldwide. Despite this high propensity for DNA exchange, little is known about the factors that limit the extent of recombination during natural transformation. Here, we identify restriction-modification (R-M) systems as a barrier to transformation with homeologous DNA and find that R-M systems and several components of the recombination machinery control integration length. Type II R-M systems, the nuclease nucT and resolvase ruvC reduced integration length whereas the helicase recG increased it. In addition, we characterized a new factor that promotes natural transformation in H. pylori, dprB. Although free recombination has been widely observed in H. pylori, our study suggests that this bacterium uses multiple systems to limit inter-strain recombination.
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Affiliation(s)
- Olivier Humbert
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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Abstract
BACKGROUND Helicobacter pylori (H. pylori) infection has been linked to the development of chronic gastritis, duodenal ulcer disease, and gastric cancer. Helicobacter pylori- infected patients and animal models develop hypergastrinemia, chronic gastritis, and gastric atrophy. Since gastrin is an important regulator of gastric acid secretion and cell growth, H. pylori regulation of this hormone has been implicated in its pathogenesis. OBJECTIVES To investigate the effect of H. pylori on gastrin gene expression in mice and of human bacterial isolates on gastrin mRNA expressed in a human cell line. METHODS Gastrin mRNA was measured by qRT-PCR in H. pylori-infected mice. H. pylori were co-cultured with AGS cells to study regulation of human gastrin gene expression. Various MAP kinases were implicated in signal transduction from the bacteria using specific inhibitors. Gastrin reporter constructs and gel shift assays were used to map DNA responsive elements. RESULTS In addition to an increase in gastrin mRNA in H. pylori-infected mice, H. pylori induced the endogenous human gastrin gene through MAP kinase-dependent signaling but not NFκB-dependent signaling. Activation of gastrin through MAPK signaling did not require CagA or VacA virulence factors. Transfection studies demonstrated that a GC-rich motif mediated H. pylori-induction of the gastrin promoter and that the motif inducibly binds Sp1 and Sp3 transcription factors. CONCLUSIONS Direct contact of live H. pylori bacteria with human cells is sufficient to induce gastrin gene expression.
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Affiliation(s)
- Tamara P Tucker
- Departments of Internal Medicine, Microbiology and Immunology and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109-2200, USA
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The coupling protein Cagbeta and its interaction partner CagZ are required for type IV secretion of the Helicobacter pylori CagA protein. Infect Immun 2010; 78:5244-51. [PMID: 20876293 DOI: 10.1128/iai.00796-10] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Bacterial type IV secretion systems are macromolecule transporters with essential functions for horizontal gene transfer and for symbiotic and pathogenic interactions with eukaryotic host cells. Helicobacter pylori, the causative agent of type B gastritis, peptic ulcers, gastric adenocarcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma, uses the Cag type IV secretion system to inject its effector protein CagA into gastric cells. This protein translocation results in altered host cell gene expression profiles and cytoskeletal rearrangements, and it has been linked to cancer development. Interactions of CagA with host cell proteins have been studied in great detail, but little is known about the molecular details of CagA recognition as a type IV secretion substrate or of the translocation process. Apart from components of the secretion apparatus, we previously identified several CagA translocation factors that are either required for or support CagA translocation. To identify protein-protein interactions between these translocation factors, we used a yeast two-hybrid approach comprising all cag pathogenicity island genes. Among several other interactions involving translocation factors, we found a strong interaction between the coupling protein homologue Cagβ (HP0524) and the Cag-specific translocation factor CagZ (HP0526). We show that CagZ has a stabilizing effect on Cagβ, and we demonstrate protein-protein interactions between the cytoplasmic part of Cagβ and CagA and between CagZ and Cagβ, using immunoprecipitation and pull-down assays. Together, our data suggest that these interactions represent a substrate-translocation factor complex at the bacterial cytoplasmic membrane.
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Olbermann P, Josenhans C, Moodley Y, Uhr M, Stamer C, Vauterin M, Suerbaum S, Achtman M, Linz B. A global overview of the genetic and functional diversity in the Helicobacter pylori cag pathogenicity island. PLoS Genet 2010; 6:e1001069. [PMID: 20808891 PMCID: PMC2924317 DOI: 10.1371/journal.pgen.1001069] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 07/15/2010] [Indexed: 12/16/2022] Open
Abstract
The Helicobacter pylori cag pathogenicity island (cagPAI) encodes a type IV secretion system. Humans infected with cagPAI–carrying H. pylori are at increased risk for sequelae such as gastric cancer. Housekeeping genes in H. pylori show considerable genetic diversity; but the diversity of virulence factors such as the cagPAI, which transports the bacterial oncogene CagA into host cells, has not been systematically investigated. Here we compared the complete cagPAI sequences for 38 representative isolates from all known H. pylori biogeographic populations. Their gene content and gene order were highly conserved. The phylogeny of most cagPAI genes was similar to that of housekeeping genes, indicating that the cagPAI was probably acquired only once by H. pylori, and its genetic diversity reflects the isolation by distance that has shaped this bacterial species since modern humans migrated out of Africa. Most isolates induced IL-8 release in gastric epithelial cells, indicating that the function of the Cag secretion system has been conserved despite some genetic rearrangements. More than one third of cagPAI genes, in particular those encoding cell-surface exposed proteins, showed signatures of diversifying (Darwinian) selection at more than 5% of codons. Several unknown gene products predicted to be under Darwinian selection are also likely to be secreted proteins (e.g. HP0522, HP0535). One of these, HP0535, is predicted to code for either a new secreted candidate effector protein or a protein which interacts with CagA because it contains two genetic lineages, similar to cagA. Our study provides a resource that can guide future research on the biological roles and host interactions of cagPAI proteins, including several whose function is still unknown. Most humans are infected with Helicobacter pylori. The H. pylori cag pathogenicity island (cagPAI) encodes a secretion apparatus that can translocate the CagA protein into host cells. Humans infected with cagPAI–carrying H. pylori are at increased risk of severe disease, including gastric cancer. We analyzed the nucleotide sequences and functional diversity of the cagPAI in a globally representative collection of isolates. Complete cagPAI sequences were obtained for 29 strains from all known H. pylori biogeographic populations. The gene content and arrangement of the cagPAI and its function were highly conserved. Diversity in most cag genes consisted in large part of synonymous polymorphisms. However some genes—in particular those that encode proteins predicted to be secreted or located on the outside of the bacterial cell—had particularly high frequencies of non-synonymous polymorphisms, suggesting that they were under diversifying selection. Our study provides evidence that the cagPAI was only acquired once and provides an important resource that can guide future research on the biological roles and host interactions of cagPAI proteins, including several whose function is still unknown.
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Affiliation(s)
- Patrick Olbermann
- Institute for Medical Microbiology and Hospital Epidemiology, Medizinische Hochschule Hannover, Hannover, Germany
| | - Christine Josenhans
- Institute for Medical Microbiology and Hospital Epidemiology, Medizinische Hochschule Hannover, Hannover, Germany
| | - Yoshan Moodley
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Markus Uhr
- Institute for Medical Microbiology and Hospital Epidemiology, Medizinische Hochschule Hannover, Hannover, Germany
| | - Christiana Stamer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | | | - Sebastian Suerbaum
- Institute for Medical Microbiology and Hospital Epidemiology, Medizinische Hochschule Hannover, Hannover, Germany
- * E-mail: ;
| | - Mark Achtman
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
- Environmental Research Institute, University College Cork, Cork, Ireland
- * E-mail: ;
| | - Bodo Linz
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
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