151
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Castiblanco LF, Triplett LR, Sundin GW. Regulation of Effector Delivery by Type III Secretion Chaperone Proteins in Erwinia amylovora. Front Microbiol 2018; 9:146. [PMID: 29472907 PMCID: PMC5809446 DOI: 10.3389/fmicb.2018.00146] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/23/2018] [Indexed: 11/16/2022] Open
Abstract
Type III secretion (TTS) chaperones are critical for the delivery of many effector proteins from Gram-negative bacterial pathogens into host cells, functioning in the stabilization and hierarchical delivery of the effectors to the type III secretion system (TTSS). The plant pathogen Erwinia amylovora secretes at least four TTS effector proteins: DspE, Eop1, Eop3, and Eop4. DspE specifically interacts with the TTS chaperone protein DspF, which stabilizes the effector protein in the cytoplasm and promotes its efficient translocation through the TTSS. However, the role of E. amylovora chaperones in regulating the delivery of other secreted effectors is unknown. In this study, we identified functional interactions between the effector proteins DspE, Eop1, and Eop3 with the TTS chaperones DspF, Esc1 and Esc3 in yeast. Using site-directed mutagenesis, secretion, and translocation assays, we demonstrated that the three TTS chaperones have additive roles for the secretion and translocation of DspE into plant cells whereas DspF negatively affects the translocation of Eop1 and Eop3. Collectively, these results indicate that TTS chaperone proteins exhibit a cooperative behavior to orchestrate the effector secretion and translocation dynamics in E. amylovora.
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Affiliation(s)
- Luisa F Castiblanco
- Department of Plant, Soil and Microbial Sciences, Center for Microbial Pathogenesis, Michigan State University, East Lansing, MI, United States
| | - Lindsay R Triplett
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, CT, United States
| | - George W Sundin
- Department of Plant, Soil and Microbial Sciences, Center for Microbial Pathogenesis, Michigan State University, East Lansing, MI, United States
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152
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Dortet L, Lombardi C, Cretin F, Dessen A, Filloux A. Pore-forming activity of the Pseudomonas aeruginosa type III secretion system translocon alters the host epigenome. Nat Microbiol 2018; 3:378-386. [PMID: 29403015 DOI: 10.1038/s41564-018-0109-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/21/2017] [Indexed: 12/13/2022]
Abstract
Recent studies highlight that bacterial pathogens can reprogram target cells by influencing epigenetic factors. The type III secretion system (T3SS) is a bacterial nanomachine that resembles a syringe on the bacterial surface. The T3SS 'needle' delivers translocon proteins into eukaryotic cell membranes, subsequently allowing injection of bacterial effectors into the cytosol. Here we show that Pseudomonas aeruginosa induces early T3SS-dependent dephosphorylation and deacetylation of histone H3 in eukaryotic cells. This is not triggered by any of the P. aeruginosa T3SS effectors, but results from the insertion of the PopB-PopD translocon into the membrane. This suggests that the P. aeruginosa translocon is a genuine T3SS effector acting as a pore-forming toxin. We visualized the translocon plugged into the host cell membrane after the bacterium has left the site of contact, and demonstrate that subsequent ion exchange through this pore is responsible for histone H3 modifications and host cell subversion.
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Affiliation(s)
- Laurent Dortet
- MRC Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, London, UK.,EA7361 'Structure, dynamic, function and expression of broad spectrum β-lactamases', Faculty of Medicine, Paris-Sud University, LabEx Lermit, Le Kremlin-Bicêtre, France
| | - Charlotte Lombardi
- Institut de Biologie Structurale (IBS), University Grenoble-Alpes, CEA, CNRS, Bacterial Pathogenesis Group, Grenoble, France
| | - François Cretin
- University Grenoble-Alpes, Bacterial Pathogenesis and Cellular Responses, CNRS-ERL5261, U1036_S, INSERM, Biosciences and Biotechnology Institute of Grenoble, CEA-Grenoble, Grenoble, France
| | - Andréa Dessen
- Institut de Biologie Structurale (IBS), University Grenoble-Alpes, CEA, CNRS, Bacterial Pathogenesis Group, Grenoble, France.,Brazilian Biosciences National Laboratory (LNBio), CNPEM, São Paulo, Brazil
| | - Alain Filloux
- MRC Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, London, UK.
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153
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Chalupowicz L, Nissan G, Brandl MT, McClelland M, Sessa G, Popov G, Barash I, Manulis-Sasson S. Assessing the Ability of Salmonella enterica to Translocate Type III Effectors Into Plant Cells. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:233-239. [PMID: 28952399 DOI: 10.1094/mpmi-07-17-0166-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Salmonella enterica serovar Typhimurium, a human enteric pathogen, has the ability to multiply and survive endophytically in plants. Genes encoding the type III secretion system (T3SS) or its effectors (T3Es) may contribute to its colonization. Two reporter plasmids for T3E translocation into plant cells that are based on hypersensitive response domains of avirulence proteins from the Pantoea agglomerans-beet and Xanthomonas euvesicatoria-pepper pathosystems were employed in this study to investigate the role of T3Es in the interaction of Salmonella ser. Typhimurium 14028 with plants. The T3Es of Salmonella ser. Typhimurium, SipB and SifA, which are translocated into animal cells, could not be delivered by Salmonella ser. Typhimurium into cells of beet roots or pepper leaves. In contrast, these effectors were translocated into plant cells by the phytopathogenic bacteria P. agglomerans pv. betae, Erwinia amylovora, and X. euvesicatoria. Similarly, HsvG, a T3E of P. agglomerans pv. gypsophilae, and XopAU of X. euvesicatoria could be translocated into beet roots and pepper leaves, respectively, by the plant pathogens but not by Salmonella ser. Typhimurium. Mutations in Salmonella ser. Typhimurium T3SS genes invA, ssaV, sipB, or sifA, did not affect its endophytic colonization of lettuce leaves, supporting the notion that S. enterica cannot translocate T3Es into plant cells.
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Affiliation(s)
- Laura Chalupowicz
- 1 Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel
| | - Gal Nissan
- 1 Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel
- 2 School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv 69978, Israel
| | - Maria T Brandl
- 3 Produce Safety and Microbiology Research Unit, USDA, ARS, WRRC, 800 Buchanan St., Albany, CA 94710, U.S.A.; and
| | - Michael McClelland
- 4 Department of Microbiology, School of Medicine, University of California, Irvine, CA 92697-4025, U.S.A
| | - Guido Sessa
- 2 School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv 69978, Israel
| | - Georgy Popov
- 2 School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv 69978, Israel
| | - Isaac Barash
- 2 School of Plant Sciences and Food Security, Faculty of Life Sciences, Tel-Aviv 69978, Israel
| | - Shulamit Manulis-Sasson
- 1 Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel
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154
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Rocha JM, Richardson CJ, Zhang M, Darch CM, Cai E, Diepold A, Gahlmann A. Single-molecule tracking in liveYersinia enterocoliticareveals distinct cytosolic complexes of injectisome subunits. Integr Biol (Camb) 2018; 10:502-515. [DOI: 10.1039/c8ib00075a] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Single-molecule tracking of bound (blue trajectories) and diffusive (red trajectories) injectisome subunits reveals the formation of distinct cytosolic complexes.
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Affiliation(s)
| | | | - Mingxing Zhang
- Department of Chemistry, University of Virginia
- Charlottesville
- USA
| | | | - Eugene Cai
- Department of Chemistry, University of Virginia
- Charlottesville
- USA
| | - Andreas Diepold
- Department of Ecophysiology
- Max Planck Institute for Terrestrial Microbiology
- Marburg
- Germany
| | - Andreas Gahlmann
- Department of Chemistry, University of Virginia
- Charlottesville
- USA
- Department of Molecular Physiology & Biological Physics, University of Virginia School of Medicine
- Charlottesville
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155
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El Hajjami N, Moussa S, Houssa J, Monteyne D, Perez-Morga D, Botteaux A. The inner-rod component of Shigella flexneri type 3 secretion system, MxiI, is involved in the transmission of the secretion activation signal by its interaction with MxiC. Microbiologyopen 2017; 7. [PMID: 29194994 PMCID: PMC5822323 DOI: 10.1002/mbo3.520] [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: 01/13/2017] [Revised: 05/29/2017] [Accepted: 06/13/2017] [Indexed: 11/28/2022] Open
Abstract
The virulence of Shigella mainly resides in the use of a Type 3 Secretion System (T3SS) to inject several proteins inside the host cell. Three categories of proteins are hierarchically secreted: (1) the needle components (MxiH and MxiI), (2) the translocator proteins which form a pore (translocon) inside the host cell membrane, and (3) the effectors interfering with the host cell signaling pathways. In the absence of host cell contact, the T3SS is maintained in an “off” state by the presence of a tip complex. We have previously identified a gatekeeper protein, MxiC, which sequesters effectors inside the bacteria probably by interacting with MxiI, the inner‐rod component. Upon cell contact and translocon insertion, a signal is most likely transmitted from the top of the needle to the base, passing through the needle and allowing effectors release. However, the molecular mechanism underlying the transmission of the activation signal through the needle is still poorly understood. In this work, we investigate the role of MxiI in the activation of the T3SS by performing a mutational study. Interestingly we have shown that mutations of a single residue in MxiI (T82) induce an mxiC‐like phenotype and prevent the interaction with MxiC. Moreover, we have shown that the L26A mutation significantly reduces T3 secretion. The L26A mutation impairs the interaction between MxiI and Spa40, a keystone component of the switch between needle assembly and translocators secretion. The L26A mutation also sequesters MxiC. All these results highlight the crucial role of MxiI in regulating the secretion and transmitting the activation signal of the T3SS.
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Affiliation(s)
- Nargisse El Hajjami
- Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Simon Moussa
- Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Jonathan Houssa
- Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Daniel Monteyne
- Laboratoire de Parasitologie Moléculaire, Faculté des Sciences, Université Libre de Bruxelles, Charleroi, Belgium.,Center for Microscopy and Molecular Imaging-CMMI, Université Libre de Bruxelles, Gosselies, Belgium
| | - David Perez-Morga
- Laboratoire de Parasitologie Moléculaire, Faculté des Sciences, Université Libre de Bruxelles, Charleroi, Belgium
| | - Anne Botteaux
- Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Bruxelles, Belgium
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156
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Schneider JP, Basler M. Shedding light on biology of bacterial cells. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0499. [PMID: 27672150 PMCID: PMC5052743 DOI: 10.1098/rstb.2015.0499] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2016] [Indexed: 12/11/2022] Open
Abstract
To understand basic principles of living organisms one has to know many different properties of all cellular components, their mutual interactions but also their amounts and spatial organization. Live-cell imaging is one possible approach to obtain such data. To get multiple snapshots of a cellular process, the imaging approach has to be gentle enough to not disrupt basic functions of the cell but also have high temporal and spatial resolution to detect and describe the changes. Light microscopy has become a method of choice and since its early development over 300 years ago revolutionized our understanding of living organisms. As most cellular components are indistinguishable from the rest of the cellular contents, the second revolution came from a discovery of specific labelling techniques, such as fusions to fluorescent proteins that allowed specific tracking of a component of interest. Currently, several different tags can be tracked independently and this allows us to simultaneously monitor the dynamics of several cellular components and from the correlation of their dynamics to infer their respective functions. It is, therefore, not surprising that live-cell fluorescence microscopy significantly advanced our understanding of basic cellular processes. Current cameras are fast enough to detect changes with millisecond time resolution and are sensitive enough to detect even a few photons per pixel. Together with constant improvement of properties of fluorescent tags, it is now possible to track single molecules in living cells over an extended period of time with a great temporal resolution. The parallel development of new illumination and detection techniques allowed breaking the diffraction barrier and thus further pushed the resolution limit of light microscopy. In this review, we would like to cover recent advances in live-cell imaging technology relevant to bacterial cells and provide a few examples of research that has been possible due to imaging. This article is part of the themed issue ‘The new bacteriology’.
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Affiliation(s)
- Johannes P Schneider
- Focal Area Infection Biology, Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Marek Basler
- Focal Area Infection Biology, Biozentrum, University of Basel, 4056 Basel, Switzerland
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157
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Ward E, Renault TT, Kim EA, Erhardt M, Hughes KT, Blair DF. Type-III secretion pore formed by flagellar protein FliP. Mol Microbiol 2017; 107:94-103. [PMID: 29076571 DOI: 10.1111/mmi.13870] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 10/14/2017] [Accepted: 10/23/2017] [Indexed: 11/29/2022]
Abstract
During assembly of the bacterial flagellum, protein subunits that form the exterior structures are exported through a specialized secretion apparatus energized by the proton gradient. This category of protein transport, together with the similar process that occurs in the injectisomes of gram-negative pathogens, is termed type-III secretion. The membrane-embedded part of the flagellar export apparatus contains five essential proteins: FlhA, FlhB, FliP, FliQ and FliR. Here, we have undertaken a variety of experiments that together support the proposal that the protein-conducting conduit is formed primarily, and possibly entirely, by FliP. Chemical modification experiments demonstrate that positions near the center of certain FliP trans-membrane (TM) segments are accessible to polar reagents. FliP expression sensitizes cells to a number of chemical agents, and mutations at predicted channel-facing positions modulate this effect. Multiple assays are used to show that FliP suffices to form a channel that can conduct a variety of medium-sized, polar molecules. Conductance properties are strongly modulated by mutations in a methionine-rich loop that is predicted to lie at the inner mouth of the channel, which might form a gasket around cargo molecules undergoing export. The results are discussed in the framework of an hypothesis for the architecture and action of the cargo-conducting part of the type-III secretion apparatus.
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Affiliation(s)
- Elizabeth Ward
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Thibaud T Renault
- Helmholtz Centre for Infection Research, Inhoffenstr. 7, Braunschweig, 38124, Germany.,Max Planck Institute for Infection Biology, Charitéplatz 1, Campus Charité Mitte, Berlin, 10117, Germany
| | - Eun A Kim
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Marc Erhardt
- Helmholtz Centre for Infection Research, Inhoffenstr. 7, Braunschweig, 38124, Germany
| | - Kelly T Hughes
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - David F Blair
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
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158
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Kitao A, Hata H. Molecular dynamics simulation of bacterial flagella. Biophys Rev 2017; 10:617-629. [PMID: 29181743 DOI: 10.1007/s12551-017-0338-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/07/2017] [Indexed: 12/31/2022] Open
Abstract
The bacterial flagellum is a biological nanomachine for the locomotion of bacteria, and is seen in organisms like Salmonella and Escherichia coli. The flagellum consists of tens of thousands of protein molecules and more than 30 different kinds of proteins. The basal body of the flagellum contains a protein export apparatus and a rotary motor that is powered by ion motive force across the cytoplasmic membrane. The filament functions as a propeller whose helicity is controlled by the direction of the torque. The hook that connects the motor and filament acts as a universal joint, transmitting torque generated by the motor to different directions. This report describes the use of molecular dynamics to study the bacterial flagellum. Molecular dynamics simulation is a powerful method that permits the investigation, at atomic resolution, of the molecular mechanisms of biomolecular systems containing many proteins and solvent. When applied to the flagellum, these studies successfully unveiled the polymorphic supercoiling and transportation mechanism of the filament, the universal joint mechanism of the hook, the ion transfer mechanism of the motor stator, the flexible nature of the transport apparatus proteins, and activation of proteins involved in chemotaxis.
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Affiliation(s)
- Akio Kitao
- School of Life Science and Technology, Tokyo Institute of Technology, M6-13, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan.
| | - Hiroaki Hata
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
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159
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The role of EscD in supporting EscC polymerization in the type III secretion system of enteropathogenic Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:384-395. [PMID: 28988128 DOI: 10.1016/j.bbamem.2017.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 10/01/2017] [Accepted: 10/02/2017] [Indexed: 11/23/2022]
Abstract
The type III secretion system (T3SS) is a multi-protein complex that plays a central role in the virulence of many Gram-negative bacterial pathogens. In enteropathogenic Escherichia coli, a prevalent cause of diarrheal diseases, the needle complex base of the T3SS is formed by multi-rings: two concentric inner-membrane rings made by the two oligomerizing proteins (EscD and EscJ), and an outer ring made of a single oligomerizing protein (EscC). Although the oligomerization activity of these proteins is critical for their function and can, therefore, affect the virulence of the pathogen, the mechanisms underlying the oligomerization of these proteins have yet to be identified. In this study, we report that the proteins forming the inner-membrane T3SS rings, EscJ and EscD proteins, are crucial for the oligomerization of EscC. Moreover, we elucidate the oligomerization process of EscD and determine the contribution of individual regions of the protein to its self-oligomerization activity. We show that the oligomerization motif of EscD is located at its N-terminal portion and that its transmembrane domain can self-oligomerize, thus contributing to the self-oligomerization of the full-length EscD.
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160
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Cheng S, Wang L, Liu Q, Qi L, Yu K, Wang Z, Wu M, Liu Y, Fu J, Hu M, Li M, Zhou D, Liu X. Identification of a Novel Salmonella Type III Effector by Quantitative Secretome Profiling. Mol Cell Proteomics 2017; 16:2219-2228. [PMID: 28887382 DOI: 10.1074/mcp.ra117.000230] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Indexed: 11/06/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is arguably one of the most studied bacterial pathogens and successful infection requires the delivery of its virulence factors (effectors) directly into host cells via the type III secretion systems (T3SSs). Central to Salmonella pathogenesis, these effector proteins have been subjected to extensive studies over the years. Nevertheless, whether additional effectors exist remains unclear. Here we report the identification of a novel Salmonella T3SS effector STM1239 (which we renamed SopF) via quantitative secretome profiling. Immunoblotting and β-lactamase reporter assays confirmed the secretion and translocation of SopF in a T3SS-dependent manner. Moreover, ectopic expression of SopF caused significant toxicity in yeast cells. Importantly, genetic ablation of sopF led to Salmonella strains defective in intracellular replication within macrophages and the mutant were also markedly attenuated in a mouse model of infection. Our study underscores the use of quantitative secretome profiling in identifying novel virulence factors for bacterial pathogens.
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Affiliation(s)
- Sen Cheng
- From the ‡Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871
| | - Lu Wang
- §Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | - Qian Liu
- ¶Department of Laboratory Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China 200127
| | - Linlu Qi
- From the ‡Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871
| | - Kaiwen Yu
- From the ‡Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871
| | - Zhen Wang
- From the ‡Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871
| | - Mei Wu
- From the ‡Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871
| | - Yanhua Liu
- From the ‡Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871
| | - Jiaqi Fu
- From the ‡Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871
| | - Mo Hu
- From the ‡Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871
| | - Min Li
- ¶Department of Laboratory Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China 200127
| | - Daoguo Zhou
- §Department of Biological Sciences, Purdue University, West Lafayette, IN 47907; .,‖TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China 300457
| | - Xiaoyun Liu
- From the ‡Institute of Analytical Chemistry and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China 100871;
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161
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Inhibitory effect of obovatol from Magnolia obovata on the Salmonella type III secretion system. J Antibiot (Tokyo) 2017; 70:1065-1069. [DOI: 10.1038/ja.2017.98] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/26/2017] [Accepted: 07/28/2017] [Indexed: 12/21/2022]
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162
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Barta ML, Shearer JP, Arizmendi O, Tremblay JM, Mehzabeen N, Zheng Q, Battaile KP, Lovell S, Tzipori S, Picking WD, Shoemaker CB, Picking WL. Single-domain antibodies pinpoint potential targets within Shigella invasion plasmid antigen D of the needle tip complex for inhibition of type III secretion. J Biol Chem 2017; 292:16677-16687. [PMID: 28842484 DOI: 10.1074/jbc.m117.802231] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/14/2017] [Indexed: 12/18/2022] Open
Abstract
Numerous Gram-negative pathogens infect eukaryotes and use the type III secretion system (T3SS) to deliver effector proteins into host cells. One important T3SS feature is an extracellular needle with an associated tip complex responsible for assembly of a pore-forming translocon in the host cell membrane. Shigella spp. cause shigellosis, also called bacillary dysentery, and invade colonic epithelial cells via the T3SS. The tip complex of Shigella flexneri contains invasion plasmid antigen D (IpaD), which initially regulates secretion and provides a physical platform for the translocon pore. The tip complex represents a promising therapeutic target for many important T3SS-containing pathogens. Here, in an effort to further elucidate its function, we created a panel of single-VH domain antibodies (VHHs) that recognize distinct epitopes within IpaD. These VHHs recognized the in situ tip complex and modulated the infectious properties of Shigella Moreover, structural elucidation of several IpaD-VHH complexes provided critical insights into tip complex formation and function. Of note, one VHH heterodimer could reduce Shigella hemolytic activity by >80%. Our observations along with previous findings support the hypothesis that the hydrophobic translocator (IpaB in Shigella) likely binds to a region within the tip protein that is structurally conserved across all T3SS-possessing pathogens, suggesting potential therapeutic avenues for managing infections by these pathogens.
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Affiliation(s)
- Michael L Barta
- From the Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047
| | - Jonathan P Shearer
- Department of Infectious Diseases and Global Health, Tufts Clinical and Translational Science Institute, North Grafton, Massachusetts 02111
| | - Olivia Arizmendi
- From the Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047
| | - Jacqueline M Tremblay
- Department of Infectious Diseases and Global Health, Tufts Clinical and Translational Science Institute, North Grafton, Massachusetts 02111
| | - Nurjahan Mehzabeen
- Protein Structure Laboratory, Del Shankel Structural Biology Center, University of Kansas, Lawrence, Kansas 66047, and
| | - Qi Zheng
- From the Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047
| | - Kevin P Battaile
- IMCA-CAT, Hauptman-Woodward Medical Research Institute, Argonne, Illinois 60439
| | - Scott Lovell
- Protein Structure Laboratory, Del Shankel Structural Biology Center, University of Kansas, Lawrence, Kansas 66047, and
| | - Saul Tzipori
- Department of Infectious Diseases and Global Health, Tufts Clinical and Translational Science Institute, North Grafton, Massachusetts 02111
| | - William D Picking
- From the Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047
| | - Charles B Shoemaker
- Department of Infectious Diseases and Global Health, Tufts Clinical and Translational Science Institute, North Grafton, Massachusetts 02111
| | - Wendy L Picking
- From the Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047,
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163
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Synthetic Cyclic Peptomers as Type III Secretion System Inhibitors. Antimicrob Agents Chemother 2017; 61:AAC.00060-17. [PMID: 28652236 DOI: 10.1128/aac.00060-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 06/10/2017] [Indexed: 12/12/2022] Open
Abstract
Antibiotic-resistant bacteria are an emerging threat to global public health. New classes of antibiotics and tools for antimicrobial discovery are urgently needed. Type III secretion systems (T3SS), which are required by dozens of Gram-negative bacteria for virulence but largely absent from nonpathogenic bacteria, are promising virulence blocker targets. The ability of mammalian cells to recognize the presence of a functional T3SS and trigger NF-κB activation provides a rapid and sensitive method for identifying chemical inhibitors of T3SS activity. In this study, we generated a HEK293 stable cell line expressing green fluorescent protein (GFP) driven by a promoter containing NF-κB enhancer elements to serve as a readout of T3SS function. We identified a family of synthetic cyclic peptide-peptoid hybrid molecules (peptomers) that exhibited dose-dependent inhibition of T3SS effector secretion in Yersinia pseudotuberculosis and Pseudomonas aeruginosa without affecting bacterial growth or motility. Among these inhibitors, EpD-3'N, EpD-1,2N, EpD-1,3'N, EpD-1,2,3'N, and EpD-1,2,4'N exhibited strong inhibitory effects on translocation of the Yersinia YopM effector protein into mammalian cells (>40% translocation inhibition at 7.5 μM) and showed no toxicity to mammalian cells at 240 μM. In addition, EpD-3'N and EpD-1,2,4'N reduced the rounding of HeLa cells caused by the activity of Yersinia effector proteins that target the actin cytoskeleton. In summary, we have discovered a family of novel cyclic peptomers that inhibit the injectisome T3SS but not the flagellar T3SS.
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164
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Young AM, Minson M, McQuate SE, Palmer AE. Optimized Fluorescence Complementation Platform for Visualizing Salmonella Effector Proteins Reveals Distinctly Different Intracellular Niches in Different Cell Types. ACS Infect Dis 2017; 3:575-584. [PMID: 28551989 PMCID: PMC5720895 DOI: 10.1021/acsinfecdis.7b00052] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The bacterial pathogen Salmonella uses sophisticated type III secretion systems (T3SS) to translocate and deliver bacterial effector proteins into host cells to establish infection. Monitoring these important virulence determinants in the context of live infections is a key step in defining the dynamic interface between the host and pathogen. Here, we provide a modular labeling platform based on fluorescence complementation with split-GFP that permits facile tagging of new Salmonella effector proteins. We demonstrate enhancement of split-GFP complementation signals by manipulating the promoter or by multimerizing the fluorescent tag and visualize three effector proteins, SseF, SseG, and SlrP, that have never before been visualized over time during infection of live cells. Using this platform, we developed a methodology for visualizing effector proteins in primary macrophage cells for the first time and reveal distinct differences in the effector-defined intracellular niche between primary macrophage and commonly used HeLa and RAW cell lines.
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Affiliation(s)
- Alexandra M. Young
- Department of Chemistry and Biochemistry, BioFrontiers Institute, UCB 596, 3415 Colorado Ave, University of Colorado, Boulder, CO 80303
| | - Michael Minson
- Department of Chemistry and Biochemistry, BioFrontiers Institute, UCB 596, 3415 Colorado Ave, University of Colorado, Boulder, CO 80303
| | - Sarah E. McQuate
- Department of Chemistry and Biochemistry, BioFrontiers Institute, UCB 596, 3415 Colorado Ave, University of Colorado, Boulder, CO 80303
| | - Amy E. Palmer
- Department of Chemistry and Biochemistry, BioFrontiers Institute, UCB 596, 3415 Colorado Ave, University of Colorado, Boulder, CO 80303
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165
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Panopoulos NJ. A Career on Both Sides of the Atlantic: Memoirs of a Molecular Plant Pathologist. ANNUAL REVIEW OF PHYTOPATHOLOGY 2017; 55:1-21. [PMID: 28777925 DOI: 10.1146/annurev-phyto-080516-035506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This article recounts the experiences that shaped my career as a molecular plant pathologist. It focuses primarily on technical and conceptual developments in molecular phytobacteriology, shares some personal highlights and untold stories that impacted my professional development, and describes the early years of agricultural biotechnology. Writing this article required reflection on events occurring over several decades that were punctuated by a mid-career relocation across the Atlantic. I hope it will still be useful, informative, and enjoyable to read. An extended version of the abstract is provided in the Supplemental Materials , available online.
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Affiliation(s)
- Nickolas J Panopoulos
- Professor Emeritus, Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94619
- Department of Biology, University of Crete, Heraklion, GR-71003, Greece;
- Hellenic Agricultural Academy, Agricultural University of Athens, 118 55 Athens, Greece
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166
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Fabiani FD, Renault TT, Peters B, Dietsche T, Gálvez EJC, Guse A, Freier K, Charpentier E, Strowig T, Franz-Wachtel M, Macek B, Wagner S, Hensel M, Erhardt M. A flagellum-specific chaperone facilitates assembly of the core type III export apparatus of the bacterial flagellum. PLoS Biol 2017; 15:e2002267. [PMID: 28771474 PMCID: PMC5542435 DOI: 10.1371/journal.pbio.2002267] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 06/30/2017] [Indexed: 11/21/2022] Open
Abstract
Many bacteria move using a complex, self-assembling nanomachine, the bacterial flagellum. Biosynthesis of the flagellum depends on a flagellar-specific type III secretion system (T3SS), a protein export machine homologous to the export machinery of the virulence-associated injectisome. Six cytoplasmic (FliH/I/J/G/M/N) and seven integral-membrane proteins (FlhA/B FliF/O/P/Q/R) form the flagellar basal body and are involved in the transport of flagellar building blocks across the inner membrane in a proton motive force-dependent manner. However, how the large, multi-component transmembrane export gate complex assembles in a coordinated manner remains enigmatic. Specific for most flagellar T3SSs is the presence of FliO, a small bitopic membrane protein with a large cytoplasmic domain. The function of FliO is unknown, but homologs of FliO are found in >80% of all flagellated bacteria. Here, we demonstrate that FliO protects FliP from proteolytic degradation and promotes the formation of a stable FliP–FliR complex required for the assembly of a functional core export apparatus. We further reveal the subcellular localization of FliO by super-resolution microscopy and show that FliO is not part of the assembled flagellar basal body. In summary, our results suggest that FliO functions as a novel, flagellar T3SS-specific chaperone, which facilitates quality control and productive assembly of the core T3SS export machinery. Many bacteria use the bacterial flagellum for directed movement in various environments. The assembly and function of the bacterial flagellum and the related virulence-associated injectisome relies on protein export via a conserved type III secretion system (T3SS). The multicomponent transmembrane core export apparatus of the flagellar T3SS consists of FlhA/B and FliP/Q/R and must assemble in a highly coordinated manner. In the present study, we determined the role of the transmembrane protein FliO in the maturation of the flagellar core protein export apparatus. We show that FliO functions as a flagellum-specific chaperone during the initial step of export apparatus assembly. FliO facilitates the efficient formation of a stable FliP–FliR core complex and is thus required for quality management and productive assembly of the flagellar export apparatus. Our results suggest a coordinated assembly process of the flagellar core export apparatus that nucleates with the FliO-dependent formation of a FliP–FliR complex. Subsequent incorporation of FliQ, FlhB, and FlhA leads to the assembly of a secretion-competent flagellar T3SS.
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Affiliation(s)
- Florian D. Fabiani
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Thibaud T. Renault
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Max Planck Institute for Infection Biology, Berlin, Germany
| | - Britta Peters
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, University of Osnabrück, Osnabrück, Germany
| | - Tobias Dietsche
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Section of Cellular and Molecular Microbiology, University of Tübingen, Tübingen, Germany
| | - Eric J. C. Gálvez
- Junior Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Alina Guse
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Karen Freier
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Till Strowig
- Junior Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Boris Macek
- Proteome Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Samuel Wagner
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Section of Cellular and Molecular Microbiology, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner-site Tübingen, Tübingen, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, University of Osnabrück, Osnabrück, Germany
| | - Marc Erhardt
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
- * E-mail:
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167
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Jovanovic M, Waite C, James E, Synn N, Simpson T, Kotta-Loizou I, Buck M. Functional Characterization of Key Residues in Regulatory Proteins HrpG and HrpV of Pseudomonas syringae pv. tomato DC3000. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:656-665. [PMID: 28488468 DOI: 10.1094/mpmi-03-17-0073-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The plant pathogen Pseudomonas syringae pv. tomato DC3000 uses a type III secretion system (T3SS) to transfer effector proteins into the host. The expression of T3SS proteins is controlled by the HrpL σ factor. Transcription of hrpL is σ54-dependent and bacterial enhancer-binding proteins HrpR and HrpS coactivate the hrpL promoter. The HrpV protein imposes negative control upon HrpR and HrpS through direct interaction with HrpS. HrpG interacts with HrpV and relieves such negative control. The sequence alignments across Hrp group I-type plant pathogens revealed conserved HrpV and HrpG amino acids. To establish structure-function relationships in HrpV and HrpG, either truncated or alanine substitution mutants were constructed. Key functional residues in HrpV and HrpG are found within their C-terminal regions. In HrpG, L101 and L105 are indispensable for the ability of HrpG to directly interact with HrpV and suppress HrpV-dependent negative regulation of HrpR and HrpS. In HrpV, L108 and G110 are major determinants for interactions with HrpS and HrpG. We propose that mutually exclusive binding of HrpS and HrpG to the same binding site of HrpV governs a transition from negative control to activation of the HrpRS complex leading to HrpL expression and pathogenicity of P. syringae.
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Affiliation(s)
- Milija Jovanovic
- 1 Imperial College London, Imperial College Road, London, SW7 2AZ, U.K
| | - Christopher Waite
- 1 Imperial College London, Imperial College Road, London, SW7 2AZ, U.K
| | - Ellen James
- 2 Trio Medicines Ltd., Hammersmith Medicines Research, Cumberland Avenue, London, NW10 7EW, U.K.; and
| | - Nicholas Synn
- 1 Imperial College London, Imperial College Road, London, SW7 2AZ, U.K
| | - Timothy Simpson
- 3 Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, U.K
| | - Ioly Kotta-Loizou
- 1 Imperial College London, Imperial College Road, London, SW7 2AZ, U.K
| | - Martin Buck
- 1 Imperial College London, Imperial College Road, London, SW7 2AZ, U.K
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168
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Davicino RC, Méndez-Huergo SP, Eliçabe RJ, Stupirski JC, Autenrieth I, Di Genaro MS, Rabinovich GA. Galectin-1–Driven Tolerogenic Programs AggravateYersinia enterocoliticaInfection by Repressing Antibacterial Immunity. THE JOURNAL OF IMMUNOLOGY 2017; 199:1382-1392. [DOI: 10.4049/jimmunol.1700579] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 06/15/2017] [Indexed: 12/19/2022]
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169
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A dynamic and adaptive network of cytosolic interactions governs protein export by the T3SS injectisome. Nat Commun 2017; 8:15940. [PMID: 28653671 PMCID: PMC5490264 DOI: 10.1038/ncomms15940] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 05/15/2017] [Indexed: 12/03/2022] Open
Abstract
Many bacteria use a type III secretion system (T3SS) to inject effector proteins into host cells. Selection and export of the effectors is controlled by a set of soluble proteins at the cytosolic interface of the membrane spanning type III secretion ‘injectisome’. Combining fluorescence microscopy, biochemical interaction studies and fluorescence correlation spectroscopy, we show that in live Yersinia enterocolitica bacteria these soluble proteins form complexes both at the injectisome and in the cytosol. Binding to the injectisome stabilizes these cytosolic complexes, whereas the free cytosolic complexes, which include the type III secretion ATPase, constitute a highly dynamic and adaptive network. The extracellular calcium concentration, which triggers activation of the T3SS, directly influences the cytosolic complexes, possibly through the essential component SctK/YscK, revealing a potential mechanism involved in the regulation of type III secretion. Bacterial type III secretion systems (T3SS) play important roles in pathogenesis. Here, Diepold et al. show the dynamic nature of complexes formed of essential T3SS components in live bacteria, and that extracellular calcium concentrations influence these cytosolic complexes likely via SctK/YscK.
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170
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Philip NH, Zwack EE, Brodsky IE. Activation and Evasion of Inflammasomes by Yersinia. Curr Top Microbiol Immunol 2017; 397:69-90. [PMID: 27460805 DOI: 10.1007/978-3-319-41171-2_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The innate immune system plays an essential role in initiating the early response against microbial infection, as well as instructing and shaping subsequent responses. Microbial pathogens are enormously diverse in terms of the niches they occupy, their metabolic properties and requirements, and the cellular pathways that they target. Nevertheless, innate sensing of pathogens triggers a relatively stereotyped set of responses that involve transcriptional induction of key inflammatory mediators, as well as post-translational assembly and activation of a multiprotein inflammatory complex termed 'the inflammasome.' Along with classical Pattern Recognition Receptors, the inflammasome activation pathway has emerged as a key regulator of tissue homeostasis and immune defense. Components of the inflammasome generally exist within the cell in a soluble, monomeric state, and oligomerize in response to diverse enzymatic activities associated with infection or cellular stress. Inflammasome assembly triggers activation of the pro-enzyme caspase-1, resulting in the cleavage of caspase-1 targets. The most extensively studied targets are the cytokines of the IL-1 family, but the recent discovery of Gasdermin D as a novel target of caspase-1 and the related inflammatory caspase, caspase-11, has begun to mechanistically define the links between caspase-1 activation and cell death. Cell death is a hallmark of macrophage infection by many pathogens, including the gram-negative bacterial pathogens of the genus Yersinia. Intriguingly, the activities of the Yersinia-secreted effector proteins and the type III secretion system (T3SS) itself have been linked to both inflammasome activation and evasion during infection. The balance between these activating and inhibitory activities shapes the outcome of Yersinia infection. Here, we describe the current state of knowledge on interactions between Yersinia and the inflammasome system, with the goal of integrating these findings within the general framework of inflammasome responses to microbial pathogens.
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Affiliation(s)
- Naomi H Philip
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, 19104, USA.,Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.,Immunology Graduate Group, Philadelphia, PA, 19104, USA
| | - Erin E Zwack
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, 19104, USA.,Cell and Molecular Biology Graduate Group, Philadelphia, PA, 19104, USA
| | - Igor E Brodsky
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, 19104, USA. .,Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.
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171
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Glasgow AA, Wong HT, Tullman-Ercek D. A Secretion-Amplification Role for Salmonella enterica Translocon Protein SipD. ACS Synth Biol 2017; 6:1006-1015. [PMID: 28301138 DOI: 10.1021/acssynbio.6b00335] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The bacterial type III secretion system (T3SS) is an important target for enabling high-titer production of proteins of biotechnological interest as well as for synthetic biology applications that rely on protein delivery to host cells. The T3SS forms a membrane-embedded needle complex that is capped by the translocon proteins and extends into the extracellular space. The needle tip complex in Salmonella enterica consists of three translocon proteins: SipB, SipC, and SipD. It is known that knocking out sipD disrupts T3SS regulation to cause constitutive secretion of native proteins. However, we discovered that complementation of SipD in trans via exogenous addition to T3SS-expressing cultures further improves heterologous protein secretion titers, suggesting a previously unknown but important role for this protein. Building on this knowledge, we have engineered a hyper-secreting strain of S. enterica for a greater than 100-fold improvement in the production of a variety of biotechnologically valuable heterologous proteins that are challenging to produce, such as toxic antimicrobial peptides and proteolysis-prone biopolymer proteins. We determined that transcription by several T3SS promoters is upregulated with the addition of SipD, that the N-terminal domain of SipD is sufficient to observe the increased secretion phenotype, and that the effect is post-transcriptional and post-translational. These results lend support to the use of bacterial secretion as a powerful protein production strategy, and the hypothesis that translocon proteins contribute to type III secretion regulation.
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Affiliation(s)
- Anum Azam Glasgow
- UC
Berkeley-UCSF Graduate Program in Bioengineering, University of California Berkeley, Berkeley, California 94720, United States
| | - Han Teng Wong
- Department
of Plant and Microbial Biology, University of California Berkeley, Berkeley, California 94720, United States
| | - Danielle Tullman-Ercek
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Center
for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
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172
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Zambelloni R, Connolly JPR, Huerta Uribe A, Burgess K, Marquez R, Roe AJ. Novel compounds targeting the enterohemorrhagic Escherichia coli type three secretion system reveal insights into mechanisms of secretion inhibition. Mol Microbiol 2017; 105:606-619. [PMID: 28557017 PMCID: PMC5575525 DOI: 10.1111/mmi.13719] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Anti‐virulence (AV) compounds are a promising alternative to traditional antibiotics for fighting bacterial infections. The Type Three Secretion System (T3SS) is a well‐studied and attractive AV target, given that it is widespread in more than 25 species of Gram‐negative bacteria, including enterohemorrhagic E. coli (EHEC), and as it is essential for host colonization by many pathogens. In this work, we designed, synthesized and tested a new series of compounds that block the functionality of the T3SS of EHEC. Affinity chromatography experiments identified the primary target of the compounds as the T3SS needle pore protein EspD, which is essential for effector protein translocation into host cells. These data were supported by mechanistic studies that determined the coiled‐coil domain 1 of EspD as a key compound‐binding site, thereby preventing correct assembly of the T3SS complex on the cell surface. However, binding of inhibitors to EspD or deletion of EspD itself did not result in transcriptional down‐regulation of effector proteins. Instead, we found the compounds to exhibit dual‐functionality by also down‐regulating transcription of the entire chromosomal locus encoding the T3SS, further demonstrating their desirability and effectiveness.
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Affiliation(s)
- Riccardo Zambelloni
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - James P R Connolly
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Alejandro Huerta Uribe
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Karl Burgess
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Rodolfo Marquez
- Department of Chemistry, Xi'an Jiaotong-Liverpool University, SIP Suzhou, 215123, China
| | - Andrew J Roe
- Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
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173
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Tian Y, Zhao Y, Shi L, Cui Z, Hu B, Zhao Y. Type VI Secretion Systems of Erwinia amylovora Contribute to Bacterial Competition, Virulence, and Exopolysaccharide Production. PHYTOPATHOLOGY 2017; 107:654-661. [PMID: 28421913 DOI: 10.1094/phyto-11-16-0393-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The type VI secretion system (T6SS) plays a major role in mediating interbacterial competition and might contribute to virulence in plant pathogenic bacteria. However, the role of T6SS in Erwinia amylovora remains unknown. In this study, 33 deletion mutants within three T6SS clusters were generated in E. amylovora strain NCPPB1665. Our results showed that all 33 mutants displayed reduced antibacterial activities against Escherichia coli as compared with that of the wild-type (WT) strain, indicating that Erwinia amylovora T6SS are functional. Of the 33 mutants, 19 exhibited reduced virulence on immature pear fruit as compared with that of the WT strain. Among them, 6, 1, and 12 genes belonged to T6SS-1, T6SS-2, and T6SS-3 clusters, respectively. Interestingly, these 19 mutants also produced less amylovoran or levan or both. These findings suggest that E. amylovora T6SS play a role in bacterial competition and virulence possibly by influencing exopolysaccharide production.
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Affiliation(s)
- Yanli Tian
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Yuqiang Zhao
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Linye Shi
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Zhongli Cui
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Baishi Hu
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Youfu Zhao
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
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174
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Kühn S, Lopez-Montero N, Chang YY, Sartori-Rupp A, Enninga J. Imaging macropinosomes during Shigella infections. Methods 2017; 127:12-22. [PMID: 28522322 DOI: 10.1016/j.ymeth.2017.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/11/2017] [Accepted: 05/10/2017] [Indexed: 12/21/2022] Open
Abstract
Macropinocytosis is the uptake of extracellular fluid within vesicles of varying size that takes place during numerous cellular processes in a large variety of cells. A growing number of pathogens, including viruses, parasites, and bacteria are known to induce macropinocytosis during their entry into targeted host cells. We have recently discovered that the human enteroinvasive, bacterial pathogen Shigella causes in situ macropinosome formation during its entry into epithelial cells. These infection-associated macropinosomes are not generated to ingest the bacteria, but are instead involved in Shigella's intracellular niche formation. They make contacts with the phagocytosed shigellae to promote vacuolar membrane rupture and their cytosolic release. Here, we provide an overview of the different imaging approaches that are currently used to analyze macropinocytosis during infectious processes with a focus on Shigella entry. We detail the advantages and disadvantages of genetically encoded reporters as well as chemical probes to trace fluid phase uptake. In addition, we report how such reporters can be combined with ultrastructural approaches for correlative light electron microscopy either in thin sections or within large volumes. The combined imaging techniques introduced here provide a detailed characterization of macropinosomes during bacterial entry, which, apart from Shigella, are relevant for numerous other ones, including Salmonella, Brucella or Mycobacteria.
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Affiliation(s)
- Sonja Kühn
- Department of Cell Biology and Infection, Institut Pasteur, Paris, France
| | | | - Yuen-Yan Chang
- Department of Cell Biology and Infection, Institut Pasteur, Paris, France
| | - Anna Sartori-Rupp
- Department of Cell Biology and Infection, Institut Pasteur, Paris, France
| | - Jost Enninga
- Department of Cell Biology and Infection, Institut Pasteur, Paris, France.
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175
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Letchumanan V, Chan KG, Khan TM, Bukhari SI, Ab Mutalib NS, Goh BH, Lee LH. Bile Sensing: The Activation of Vibrio parahaemolyticus Virulence. Front Microbiol 2017; 8:728. [PMID: 28484445 PMCID: PMC5399080 DOI: 10.3389/fmicb.2017.00728] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/07/2017] [Indexed: 01/21/2023] Open
Abstract
Bacteria must develop resistance to various inhospitable conditions in order to survive in the human gastrointestinal tract. Bile, which is secreted by the liver, and plays an important role in food digestion also has antimicrobial properties and is able to disrupt cellular homeostasis. Paradoxically, although bile is one of the guts defenses, many studies have reported that bacteria such as Vibrio parahaemolyticus can sense bile and use its presence as an environmental cue to upregulate virulence genes during infection. This article aims to discuss how bile is detected by V. parahaemolyticus and its role in regulating type III secretion system 2 leading to human infection. This bile–bacteria interaction pathway gives us a clearer understanding of the biochemical and structural analysis of the bacterial receptors involved in mediating a response to bile salts which appear to be a significant environmental cue during initiation of an infection.
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Affiliation(s)
- Vengadesh Letchumanan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of MalayaKuala Lumpur, Malaysia.,Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaSelangor, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of MalayaKuala Lumpur, Malaysia
| | - Tahir M Khan
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaSelangor, Malaysia.,Department of Pharmacy, Abasyn UniversityPeshawar, Pakistan
| | - Sarah I Bukhari
- Department of Pharmaceutics, College of Pharmacy, King Saud UniversityRiyadh, Saudi Arabia
| | - Nurul-Syakima Ab Mutalib
- UKM Medical Molecular Biology Institute, UKM Medical Centre, Universiti Kebangsaan MalaysiaKuala Lumpur, Malaysia
| | - Bey-Hing Goh
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaSelangor, Malaysia.,Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of PhayaoPhayao, Thailand
| | - Learn-Han Lee
- Novel Bacteria and Drug Discovery Research Group, School of Pharmacy, Monash University MalaysiaSelangor, Malaysia.,Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of PhayaoPhayao, Thailand
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176
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Deng X, Li M, Pan X, Zheng R, Liu C, Chen F, Liu X, Cheng Z, Jin S, Wu W. Fis Regulates Type III Secretion System by Influencing the Transcription of exsA in Pseudomonas aeruginosa Strain PA14. Front Microbiol 2017; 8:669. [PMID: 28469612 PMCID: PMC5395579 DOI: 10.3389/fmicb.2017.00669] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/31/2017] [Indexed: 11/21/2022] Open
Abstract
Fis is a versatile DNA binding protein in bacteria. It has been demonstrated in multiple bacteria that Fis plays crucial roles in regulating bacterial virulence factors and optimizing bacterial adaptation to various environments. However, the role of Fis in Pseudomonas aeruginosa virulence as well as gene regulation remains largely unknown. Here, we found that Fis was required for the virulence of P. aeruginosa in a murine acute pneumonia model. Transcriptome analysis revealed that expression of T3SS genes, including master regulator ExsA, was defective in a fis::Tn mutant. We further demonstrate that the continuous transcription of exsC, exsE, exsB, and exsA driven by the exsC promoter was required for the activation of T3SS. Fis was found to specifically bind to the exsB-exsA intergenic region and plays an essential role in the transcription elongation from exsB to exsA. Therefore, we found a novel role of Fis in the regulation of exsA expression.
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Affiliation(s)
- Xuan Deng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China
| | - Mei Li
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China
| | - Ruiping Zheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China
| | - Chang Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China
| | - Fei Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China
| | - Xue Liu
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai UniversityTianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China.,Department of Molecular Genetics and Microbiology, College of Medicine, University of FloridaGainesville, FL, USA
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China
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177
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Horstmann JA, Zschieschang E, Truschel T, de Diego J, Lunelli M, Rohde M, May T, Strowig T, Stradal T, Kolbe M, Erhardt M. Flagellin phase-dependent swimming on epithelial cell surfaces contributes to productive Salmonella gut colonisation. Cell Microbiol 2017; 19. [PMID: 28295924 DOI: 10.1111/cmi.12739] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 03/08/2017] [Indexed: 12/11/2022]
Abstract
The flagellum is a sophisticated nanomachine and an important virulence factor of many pathogenic bacteria. Flagellar motility enables directed movements towards host cells in a chemotactic process, and near-surface swimming on cell surfaces is crucial for selection of permissive entry sites. The long external flagellar filament is made of tens of thousands subunits of a single protein, flagellin, and many Salmonella serovars alternate expression of antigenically distinct flagellin proteins, FliC and FljB. However, the role of the different flagellin variants during gut colonisation and host cell invasion remains elusive. Here, we demonstrate that flagella made of different flagellin variants display structural differences and affect Salmonella's swimming behaviour on host cell surfaces. We observed a distinct advantage of bacteria expressing FliC-flagella to identify target sites on host cell surfaces and to invade epithelial cells. FliC-expressing bacteria outcompeted FljB-expressing bacteria for intestinal tissue colonisation in the gastroenteritis and typhoid murine infection models. Intracellular survival and responses of the host immune system were not altered. We conclude that structural properties of flagella modulate the swimming behaviour on host cell surfaces, which facilitates the search for invasion sites and might constitute a general mechanism for productive host cell invasion of flagellated bacteria.
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Affiliation(s)
- Julia A Horstmann
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Erik Zschieschang
- Department for Structural Infection Biology, Center for Structural Systems Biology, Hamburg, Germany.,Department for Structural Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Juana de Diego
- Department for Structural Infection Biology, Center for Structural Systems Biology, Hamburg, Germany.,Department for Structural Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Michele Lunelli
- Department for Structural Infection Biology, Center for Structural Systems Biology, Hamburg, Germany.,Department for Structural Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Till Strowig
- Junior Research Group Microbial Immune Regulation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Theresia Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Michael Kolbe
- Department for Structural Infection Biology, Center for Structural Systems Biology, Hamburg, Germany.,Department for Structural Infection Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,MIN-Faculty University Hamburg, Hamburg, Germany
| | - Marc Erhardt
- Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Braunschweig, Germany
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178
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Abstract
Type III secretion systems (T3SSs) are protein transport nanomachines that are found in Gram-negative bacterial pathogens and symbionts. Resembling molecular syringes, T3SSs form channels that cross the bacterial envelope and the host cell membrane, which enable bacteria to inject numerous effector proteins into the host cell cytoplasm and establish trans-kingdom interactions with diverse hosts. Recent advances in cryo-electron microscopy and integrative imaging have provided unprecedented views of the architecture and structure of T3SSs. Furthermore, genetic and molecular analyses have elucidated the functions of many effectors and key regulators of T3SS assembly and secretion hierarchy, which is the sequential order by which the protein substrates are secreted. As essential virulence factors, T3SSs are attractive targets for vaccines and therapeutics. This Review summarizes our current knowledge of the structure and function of this important protein secretion machinery. A greater understanding of T3SSs should aid mechanism-based drug design and facilitate their manipulation for biotechnological applications.
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179
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Wael AHH, Hisham AA. Evaluation of the role of SsaV Salmonella pathogenicity island-2 dependent type III secretion system components on the virulence behavior of Salmonella enterica serovar Typhimurium. ACTA ACUST UNITED AC 2017. [DOI: 10.5897/ajb2016.15852] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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180
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Pasztoi M, Bonifacius A, Pezoldt J, Kulkarni D, Niemz J, Yang J, Teich R, Hajek J, Pisano F, Rohde M, Dersch P, Huehn J. Yersinia pseudotuberculosis supports Th17 differentiation and limits de novo regulatory T cell induction by directly interfering with T cell receptor signaling. Cell Mol Life Sci 2017; 74:2839-2850. [PMID: 28378044 PMCID: PMC5491567 DOI: 10.1007/s00018-017-2516-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/20/2017] [Accepted: 03/28/2017] [Indexed: 11/17/2022]
Abstract
Adaptive immunity critically contributes to control acute infection with enteropathogenic Yersinia pseudotuberculosis; however, the role of CD4+ T cell subsets in establishing infection and allowing pathogen persistence remains elusive. Here, we assessed the modulatory capacity of Y. pseudotuberculosis on CD4+ T cell differentiation. Using in vivo assays, we report that infection with Y. pseudotuberculosis resulted in enhanced priming of IL-17-producing T cells (Th17 cells), whereas induction of Foxp3+ regulatory T cells (Tregs) was severely disrupted in gut-draining mesenteric lymph nodes (mLNs), in line with altered frequencies of tolerogenic and proinflammatory dendritic cell (DC) subsets within mLNs. Additionally, by using a DC-free in vitro system, we could demonstrate that Y. pseudotuberculosis can directly modulate T cell receptor (TCR) downstream signaling within naïve CD4+ T cells and Tregs via injection of effector molecules through the type III secretion system, thereby affecting their functional properties. Importantly, modulation of naïve CD4+ T cells by Y. pseudotuberculosis resulted in an enhanced Th17 differentiation and decreased induction of Foxp3+ Tregs in vitro. These findings shed light to the adjustment of the Th17-Treg axis in response to acute Y. pseudotuberculosis infection and highlight the direct modulation of CD4+ T cell subsets by altering their TCR downstream signaling.
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Affiliation(s)
- Maria Pasztoi
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Brunswick, Germany
| | - Agnes Bonifacius
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Brunswick, Germany
| | - Joern Pezoldt
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Brunswick, Germany
| | - Devesha Kulkarni
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Brunswick, Germany
| | - Jana Niemz
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Brunswick, Germany
| | - Juhao Yang
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Brunswick, Germany
| | - René Teich
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Brunswick, Germany
| | - Janina Hajek
- Department Molecular Infection Biology, Helmholtz Centre for Infection Research, 38124, Brunswick, Germany
| | - Fabio Pisano
- Department Molecular Infection Biology, Helmholtz Centre for Infection Research, 38124, Brunswick, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, 38124, Brunswick, Germany
| | - Petra Dersch
- Department Molecular Infection Biology, Helmholtz Centre for Infection Research, 38124, Brunswick, Germany
| | - Jochen Huehn
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Brunswick, Germany.
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181
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A Novel Mechanism for Protein Delivery by the Type 3 Secretion System for Extracellularly Secreted Proteins. mBio 2017; 8:mBio.00184-17. [PMID: 28351918 PMCID: PMC5371411 DOI: 10.1128/mbio.00184-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The type 3 secretion system (T3SS) is essential for bacterial virulence through delivering effector proteins directly into the host cytosol. Here, we identified an alternative delivery mechanism of virulence factors mediated by the T3SS, which consists of the association of extracellularly secreted proteins from bacteria with the T3SS to gain access to the host cytosol. Both EspC, a protein secreted as an enteropathogenic Escherichia coli (EPEC) autotransporter, and YopH, a protein detected on the surface of Yersinia, require a functional T3SS for host cell internalization; here we provide biophysical and molecular evidence to support the concept of the EspC translocation mechanism, which requires (i) an interaction between EspA and an EspC middle segment, (ii) an EspC translocation motif (21 residues that are shared with the YopH translocation motif), (iii) increases in the association and dissociation rates of EspC mediated by EspA interacting with EspD, and (iv) an interaction of EspC with the EspD/EspB translocon pore. Interestingly, this novel mechanism does not exclude the injection model (i.e., EspF) operating through the T3SS conduit; therefore, T3SS can be functioning as an internal conduit or as an external railway, which can be used to reach the translocator pore, and this mechanism appears to be conserved among different T3SS-dependent pathogens. The type 3 secretion system is essential for injection of virulence factors, which are delivered directly into the cytosol of the host cells for usurping and subverting host processes. Recent studies have shown that these effectors proteins indeed travel inside an “injectisome” conduit through a single step of translocation by connecting the bacterium and host cell cytoplasms. However, all findings are not compatible with this model. For example, both YopH, a protein detected on the surface of Yersinia, and EspC, an autotransporter protein secreted by enteropathogenic E. coli, require a functional T3SS for host cell translocation. Both proteins have an intermediate extracellular step before their T3SS-dependent translocation. Here, we show an alternative delivery mechanism for these extracellularly secreted virulence factors that are then incorporated into the T3SS to enter the cells; this novel mechanism coexists with but diverges from the canonical injection model that involves the passage of the protein inside the injectisome.
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182
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Backert S, Tegtmeyer N. Type IV Secretion and Signal Transduction of Helicobacter pylori CagA through Interactions with Host Cell Receptors. Toxins (Basel) 2017; 9:E115. [PMID: 28338646 PMCID: PMC5408189 DOI: 10.3390/toxins9040115] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 03/20/2017] [Accepted: 03/22/2017] [Indexed: 02/06/2023] Open
Abstract
Helicobacter pylori is a highly successful human bacterium, which is exceptionally equipped to persistently inhabit the human stomach. Colonization by this pathogen is associated with gastric disorders ranging from chronic gastritis and peptic ulcers to cancer. Highly virulent H. pylori strains express the well-established adhesins BabA/B, SabA, AlpA/B, OipA, and HopQ, and a type IV secretion system (T4SS) encoded by the cag pathogenicity island (PAI). The adhesins ascertain intimate bacterial contact to gastric epithelial cells, while the T4SS represents an extracellular pilus-like structure for the translocation of the effector protein CagA. Numerous T4SS components including CagI, CagL, CagY, and CagA have been shown to target the integrin-β₁ receptor followed by translocation of CagA across the host cell membrane. The interaction of CagA with membrane-anchored phosphatidylserine and CagA-containing outer membrane vesicles may also play a role in the delivery process. Translocated CagA undergoes tyrosine phosphorylation in C-terminal EPIYA-repeat motifs by oncogenic Src and Abl kinases. CagA then interacts with an array of host signaling proteins followed by their activation or inactivation in phosphorylation-dependent and phosphorylation-independent fashions. We now count about 25 host cell binding partners of intracellular CagA, which represent the highest quantity of all currently known virulence-associated effector proteins in the microbial world. Here we review the research progress in characterizing interactions of CagA with multiple host cell receptors in the gastric epithelium, including integrin-β₁, EGFR, c-Met, CD44, E-cadherin, and gp130. The contribution of these interactions to H. pylori colonization, signal transduction, and gastric pathogenesis is discussed.
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Affiliation(s)
- Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany.
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich Alexander University Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany.
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183
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Tsou LK, Yount JS, Hang HC. Epigallocatechin-3-gallate inhibits bacterial virulence and invasion of host cells. Bioorg Med Chem 2017; 25:2883-2887. [PMID: 28325635 DOI: 10.1016/j.bmc.2017.03.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 11/28/2022]
Abstract
Increasing antibiotic resistance and beneficial effects of host microbiota has motivated the search for anti-infective agents that attenuate bacterial virulence rather than growth. For example, we discovered that specific flavonoids such as baicalein and quercetin from traditional medicinal plant extracts could attenuate Salmonella enterica serovar Typhimurium type III protein secretion and invasion of host cells. Here, we show epigallocatechin-3-gallate from green tea extracts also inhibits the activity of S. Typhimurium type III protein effectors and significantly reduces bacterial invasion into host cells. These results reveal additional dietary plant metabolites that can attenuate bacterial virulence and infection of host cells.
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Affiliation(s)
- Lun K Tsou
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA; Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan Town, Miaoli County 35053, Taiwan, ROC
| | - Jacob S Yount
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA; Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA.
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184
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Nirujogi RS, Muthusamy B, Kim MS, Sathe GJ, Lakshmi PTV, Kovbasnjuk ON, Prasad TSK, Wade M, Jabbour RE. Secretome analysis of diarrhea-inducing strains of Escherichia coli. Proteomics 2017; 17. [PMID: 28070933 DOI: 10.1002/pmic.201600299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 12/19/2016] [Accepted: 01/05/2017] [Indexed: 01/05/2023]
Abstract
Secreted proteins constitute a major part of virulence factors that are responsible for pathogenesis caused by Gram-negative bacteria. Enterohemorrhagic Escherichia coli, O157:H7, is the major pathogen often causing outbreaks. However, studies have reported that the significant outbreaks caused by non-O157:H7 E. coli strains, also known as "Big-Six" serogroup strains, are increasing. There is no systematic study describing differential secreted proteins from these non-O157:H7 E. coli strains. In this study, we carried out MS-based differential secretome analysis using tandem mass tags labeling strategy of non-O157:H7 E. coli strains, O103, O111, O121, O145, O26, and O45. We identified 1241 proteins, of which 565 proteins were predicted to be secreted. We also found that 68 proteins were enriched in type III secretion system and several of them were differentially expressed across the strains. Additionally, we identified several strain-specific secreted proteins that could be used for developing potential markers for the identification and strain-level differentiation. To our knowledge, this study is the first comparative proteomic study on secretome of E. coli Big-Six serogroup and the several of these strain-specific secreted proteins can be further studied to develop potential markers for identification and strain-level differentiation. Moreover, the results of this study can be utilized in several applications, including food safety, diagnostics of E. coli outbreaks, and detection and identification of bio threats in biodefense.
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Affiliation(s)
- Raja Sekhar Nirujogi
- Institute of Bioinformatics, International Technology Park, Bangalore, India.,Centre for Bioinformatics, Pondicherry University, Puducherry, India.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Min-Sik Kim
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Applied Chemistry, Kyung Hee University, Yongin, Gyeonggi, South Korea
| | - Gajanan J Sathe
- Institute of Bioinformatics, International Technology Park, Bangalore, India.,Manipal University, Madhav Nagar, Manipal, India
| | - P T V Lakshmi
- Centre for Bioinformatics, Pondicherry University, Puducherry, India
| | - Olga N Kovbasnjuk
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - T S Keshava Prasad
- Institute of Bioinformatics, International Technology Park, Bangalore, India.,Centre for Bioinformatics, Pondicherry University, Puducherry, India.,Manipal University, Madhav Nagar, Manipal, India.,NIMHANS-IOB Proteomics and Bioinformatics Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neuro Sciences, Bangalore, India.,YU-IOB Center for Systems Biology and Molecular Medicine, Yenepoya University, Mangalore, India
| | - Mary Wade
- Research and Technology Directorate, US Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA
| | - Rabih E Jabbour
- Research and Technology Directorate, US Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA
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185
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Erhardt M, Wheatley P, Kim EA, Hirano T, Zhang Y, Sarkar MK, Hughes KT, Blair DF. Mechanism of type-III protein secretion: Regulation of FlhA conformation by a functionally critical charged-residue cluster. Mol Microbiol 2017; 104:234-249. [PMID: 28106310 DOI: 10.1111/mmi.13623] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2017] [Indexed: 11/28/2022]
Abstract
The bacterial flagellum contains a specialized secretion apparatus in its base that pumps certain protein subunits through the growing structure to their sites of installation beyond the membrane. A related apparatus functions in the injectisomes of gram-negative pathogens to export virulence factors into host cells. This mode of protein export is termed type-III secretion (T3S). Details of the T3S mechanism are unclear. It is energized by the proton gradient; here, a mutational approach was used to identify proton-binding groups that might function in transport. Conserved proton-binding residues in all the membrane components were tested. The results identify residues R147, R154 and D158 of FlhA as most critical. These lie in a small, well-conserved cytoplasmic domain of FlhA, located between transmembrane segments 4 and 5. Two-hybrid experiments demonstrate self-interaction of the domain, and targeted cross-linking indicates that it forms a multimeric array. A mutation that mimics protonation of the key acidic residue (D158N) was shown to trigger a global conformational change that affects the other, larger cytoplasmic domain that interacts with the export cargo. The results are discussed in the framework of a transport model based on proton-actuated movements in the cytoplasmic domains of FlhA.
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Affiliation(s)
- Marc Erhardt
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA.,Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, Inhoffenstraβe 7, Braunschweig, 38124, Germany
| | - Paige Wheatley
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Eun A Kim
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Takanori Hirano
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA.,Toshiba Medical Service Corporation, 1385 Shimoichigami, Otawara-shi, Tochigi, 324-8550, Japan
| | - Yang Zhang
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | | | - Kelly T Hughes
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - David F Blair
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
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186
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Milivojevic M, Dangeard AS, Kasper CA, Tschon T, Emmenlauer M, Pique C, Schnupf P, Guignot J, Arrieumerlou C. ALPK1 controls TIFA/TRAF6-dependent innate immunity against heptose-1,7-bisphosphate of gram-negative bacteria. PLoS Pathog 2017; 13:e1006224. [PMID: 28222186 PMCID: PMC5336308 DOI: 10.1371/journal.ppat.1006224] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 03/03/2017] [Accepted: 02/07/2017] [Indexed: 12/30/2022] Open
Abstract
During infection by invasive bacteria, epithelial cells contribute to innate immunity via the local secretion of inflammatory cytokines. These are directly produced by infected cells or by uninfected bystanders via connexin-dependent cell-cell communication. However, the cellular pathways underlying this process remain largely unknown. Here we perform a genome-wide RNA interference screen and identify TIFA and TRAF6 as central players of Shigella flexneri and Salmonella typhimurium-induced interleukin-8 expression. We show that threonine 9 and the forkhead-associated domain of TIFA are necessary for the oligomerization of TIFA in both infected and bystander cells. Subsequently, this process triggers TRAF6 oligomerization and NF-κB activation. We demonstrate that TIFA/TRAF6-dependent cytokine expression is induced by the bacterial metabolite heptose-1,7-bisphosphate (HBP). In addition, we identify alpha-kinase 1 (ALPK1) as the critical kinase responsible for TIFA oligomerization and IL-8 expression in response to infection with S. flexneri and S. typhimurium but also to Neisseria meningitidis. Altogether, these results clearly show that ALPK1 is a master regulator of innate immunity against both invasive and extracellular gram-negative bacteria. Epithelial cells line internal body cavities of multicellular organisms. They represent the first line of defense against various pathogens including bacteria and viruses. They can sense the presence of invasive pathogens and initiate the recruitment of immune cells to infected tissues via the local secretion of soluble factors, called chemokines. Although this phenomenon is essential for the development of an efficient immune response, the molecular mechanism underlying this process remains largely unknown. Here we demonstrate that the host proteins ALPK1, TIFA and TRAF6 act sequentially to activate the transcription factor NF-κB and regulate the production of chemokines in response to infection by the pathogens Shigella flexneri, Salmonella typhimurium and Neisseria meningitidis. In addition, we show that the production of chemokines is triggered after detection of the bacterial monosaccharide heptose-1,7-bisphosphate, found in gram-negative bacteria. In conclusion, our study uncovers a new molecular mechanism controlling inflammation during infection by gram-negative bacteria and identifies potential targets for treatments aiming at modulating inflammation during infection.
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Affiliation(s)
- Milica Milivojevic
- INSERM, U1016, Institut Cochin, Paris, France, CNRS, UMR8104, Paris, France, Université Paris Descartes, Sorbonne Paris Cité, France
| | - Anne-Sophie Dangeard
- INSERM, U1016, Institut Cochin, Paris, France, CNRS, UMR8104, Paris, France, Université Paris Descartes, Sorbonne Paris Cité, France
| | | | | | | | - Claudine Pique
- INSERM, U1016, Institut Cochin, Paris, France, CNRS, UMR8104, Paris, France, Université Paris Descartes, Sorbonne Paris Cité, France
| | | | - Julie Guignot
- INSERM, U1016, Institut Cochin, Paris, France, CNRS, UMR8104, Paris, France, Université Paris Descartes, Sorbonne Paris Cité, France
| | - Cécile Arrieumerlou
- INSERM, U1016, Institut Cochin, Paris, France, CNRS, UMR8104, Paris, France, Université Paris Descartes, Sorbonne Paris Cité, France
- * E-mail:
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187
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Piericidin A1 Blocks Yersinia Ysc Type III Secretion System Needle Assembly. mSphere 2017; 2:mSphere00030-17. [PMID: 28217742 PMCID: PMC5311113 DOI: 10.1128/msphere.00030-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 01/23/2017] [Indexed: 11/20/2022] Open
Abstract
The bacterial type III secretion system (T3SS) is widely used by both human and animal pathogens to cause disease yet remains incompletely understood. Deciphering how some natural products, such as the microbial metabolite piericidin, inhibit type III secretion can provide important insight into how the T3SS functions or is regulated. Taking this approach, we investigated the ability of piericidin to block T3SS function in several human pathogens. Surprisingly, piericidin selectively inhibited the Ysc family T3SS in enteropathogenic Yersinia but did not affect the function of a different T3SS within the same species. Furthermore, piericidin specifically blocked the formation of T3SS needles on the bacterial surface without altering the localization of several other T3SS components or regulation of T3SS gene expression. These data show that piericidin targets a mechanism important for needle assembly that is unique to the Yersinia Ysc T3SS. The type III secretion system (T3SS) is a bacterial virulence factor expressed by dozens of Gram-negative pathogens but largely absent from commensals. The T3SS is an attractive target for antimicrobial agents that may disarm pathogenic bacteria while leaving commensal populations intact. We previously identified piericidin A1 as an inhibitor of the Ysc T3SS in Yersinia pseudotuberculosis. Piericidins were first discovered as inhibitors of complex I of the electron transport chain in mitochondria and some bacteria. However, we found that piericidin A1 did not alter Yersinia membrane potential or inhibit flagellar motility powered by the proton motive force, indicating that the piericidin mode of action against Yersinia type III secretion is independent of complex I. Instead, piericidin A1 reduced the number of T3SS needle complexes visible by fluorescence microscopy at the bacterial surface, preventing T3SS translocator and effector protein secretion. Furthermore, piericidin A1 decreased the abundance of higher-order YscF needle subunit complexes, suggesting that piericidin A1 blocks YscF needle assembly. While expression of T3SS components in Yersinia are positively regulated by active type III secretion, the block in secretion by piericidin A1 was not accompanied by a decrease in T3SS gene expression, indicating that piericidin A1 may target a T3SS regulatory circuit. However, piericidin A1 still inhibited effector protein secretion in the absence of the T3SS regulator YopK, YopD, or YopN. Surprisingly, while piericidin A1 also inhibited the Y. enterocolitica Ysc T3SS, it did not inhibit the SPI-1 family Ysa T3SS in Y. enterocolitica or the Ysc family T3SS in Pseudomonas aeruginosa. Together, these data indicate that piericidin A1 specifically inhibits Yersinia Ysc T3SS needle assembly. IMPORTANCE The bacterial type III secretion system (T3SS) is widely used by both human and animal pathogens to cause disease yet remains incompletely understood. Deciphering how some natural products, such as the microbial metabolite piericidin, inhibit type III secretion can provide important insight into how the T3SS functions or is regulated. Taking this approach, we investigated the ability of piericidin to block T3SS function in several human pathogens. Surprisingly, piericidin selectively inhibited the Ysc family T3SS in enteropathogenic Yersinia but did not affect the function of a different T3SS within the same species. Furthermore, piericidin specifically blocked the formation of T3SS needles on the bacterial surface without altering the localization of several other T3SS components or regulation of T3SS gene expression. These data show that piericidin targets a mechanism important for needle assembly that is unique to the Yersinia Ysc T3SS.
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188
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Duncan MC, Herrera NG, Johnson KS, Engel JN, Auerbuch V. Bacterial internalization is required to trigger NIK-dependent NF-κB activation in response to the bacterial type three secretion system. PLoS One 2017; 12:e0171406. [PMID: 28166267 PMCID: PMC5293232 DOI: 10.1371/journal.pone.0171406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/20/2017] [Indexed: 01/11/2023] Open
Abstract
Infection of human cells with Yersinia pseudotuberculosis expressing a functional type III secretion system (T3SS) leads to activation of host NF-κB. We show that the Yersinia T3SS activates distinct NF-κB pathways dependent upon bacterial subcellular localization. We found that wildtype Yersinia able to remain extracellular triggered NF-κB activation independently of the non-canonical NF-κB kinase NIK in HEK293T cells. In contrast, Yersinia lacking the actin-targeting effectors YopEHO, which become internalized into host cells, induce a NIK-dependent response and nuclear entry of the non-canonical NF-κB subunit p52. Blocking actin polymerization and uptake of effector mutant bacteria using cytochalasin D shifted the host NF-κB response from NIK-independent to primarily NIK-dependent. We observed similar results using Pseudomonas aeruginosa, which expresses a related T3SS and the actin-targeting effector ExoT. As the NF-κB response of HEK293T cells to effectorless Yersinia has been used both as a screening tool for chemical inhibitors of the T3SS and for bacterial forward genetic screens, a better understanding of this response is important for tool optimization and interpretation.
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Affiliation(s)
- Miles C. Duncan
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Natalia G. Herrera
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Kevin S. Johnson
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Joanne N. Engel
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Victoria Auerbuch
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, Santa Cruz, California, United States of America
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189
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Nazir R, Mazurier S, Yang P, Lemanceau P, van Elsas JD. The Ecological Role of Type Three Secretion Systems in the Interaction of Bacteria with Fungi in Soil and Related Habitats Is Diverse and Context-Dependent. Front Microbiol 2017; 8:38. [PMID: 28197129 PMCID: PMC5282467 DOI: 10.3389/fmicb.2017.00038] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/06/2017] [Indexed: 12/14/2022] Open
Abstract
Bacteria and fungi constitute important organisms in many ecosystems, in particular terrestrial ones. Both organismal groups contribute significantly to biogeochemical cycling processes. Ecological theory postulates that bacteria capable of receiving benefits from host fungi are likely to evolve efficient association strategies. The purpose of this review is to examine the mechanisms that underpin the bacterial interactions with fungi in soil and other systems, with special focus on the type III secretion system (T3SS). Starting with a brief description of the versatility of the T3SS as an interaction system with diverse eukaryotic hosts, we subsequently examine the recent advances made in our understanding of its contribution to interactions with soil fungi. The analysis used data sets ranging from circumstantial evidence to gene-knockout-based experimental data. The initial finding that the abundance of T3SSs in microbiomes is often enhanced in fungal-affected habitats like the mycosphere and the mycorrhizosphere is now substantiated with in-depth knowledge of the specific systems involved. Different fungal–interactive bacteria, in positive or negative associations with partner fungi, harbor and express T3SSs, with different ecological outcomes. In some particular cases, bacterial T3SSs have been shown to modulate the physiology of its fungal partner, affecting its ecological characteristics and consequently shaping its own habitat. Overall, the analyses of the collective data set revealed that diverse T3SSs have assumed diverse roles in the interactions of bacteria with host fungi, as driven by ecological and evolutionary niche requirements.
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Affiliation(s)
- Rashid Nazir
- Department of Environmental Sciences, COMSATS Institute of Information TechnologyAbbottabad, Pakistan; Department of Soil Environmental Science, Research Centre for Eco-environmental Sciences - Chinese Academy of SciencesBeijing, China
| | - Sylvie Mazurier
- Agroécologie, AgroSup Dijon, Institut National de la Recherche Agronomique, Université Bourgogne Franche-Comté Dijon, France
| | - Pu Yang
- Department of Microbial Ecology, GELIFES, University of Groningen Groningen, Netherlands
| | - Philippe Lemanceau
- Agroécologie, AgroSup Dijon, Institut National de la Recherche Agronomique, Université Bourgogne Franche-Comté Dijon, France
| | - Jan Dirk van Elsas
- Department of Microbial Ecology, GELIFES, University of Groningen Groningen, Netherlands
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190
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Fris ME, Broach WH, Klim SE, Coschigano PW, Carroll RK, Caswell CC, Murphy ER. Sibling sRNA RyfA1 Influences Shigella dysenteriae Pathogenesis. Genes (Basel) 2017; 8:genes8020050. [PMID: 28134784 PMCID: PMC5333039 DOI: 10.3390/genes8020050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 01/17/2017] [Indexed: 12/23/2022] Open
Abstract
Small regulatory RNAs (sRNAs) of Shigella dysenteriae and other pathogens are vital for the regulation of virulence-associated genes and processes. Here, we characterize RyfA1, one member of a sibling pair of sRNAs produced by S. dysenteriae. Unlike its nearly identical sibling molecule, RyfA2, predicted to be encoded almost exclusively by non-pathogenic species, the presence of a gene encoding RyfA1, or a RyfA1-like molecule, is strongly correlated with virulence in a variety of enteropathogens. In S. dysenteriae, the overproduction of RyfA1 negatively impacts the virulence-associated process of cell-to-cell spread as well as the expression of ompC, a gene encoding a major outer membrane protein important for the pathogenesis of Shigella. Interestingly, the production of RyfA1 is controlled by a second sRNA, here termed RyfB1, the first incidence of one regulatory small RNA controlling another in S. dysenteriae or any Shigella species.
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Affiliation(s)
- Megan E Fris
- Department of Biological Sciences, Ohio University, 1 Ohio University Drive Athens, Athens, OH 45701, USA.
| | - William H Broach
- OU Genomics Core Facility, Ohio University, 1 Ohio University Drive Athens, Athens, OH 45701, USA.
| | - Sarah E Klim
- Department of Biological Sciences, Ohio University, 1 Ohio University Drive Athens, Athens, OH 45701, USA.
| | - Peter W Coschigano
- Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine, 1 Ohio University Drive Athens, Athens, OH 45701, USA.
| | - Ronan K Carroll
- Department of Biological Sciences, Ohio University, 1 Ohio University Drive Athens, Athens, OH 45701, USA.
| | - Clayton C Caswell
- Department of Biomedical Sciences and Pathobiology, Center for Molecular Medicine and Infectious Diseases, VA-MD College of Veterinary Medicine, Virginia Tech, 1410 Prices Fork Rd., Blacksburg, VA 24060, USA.
| | - Erin R Murphy
- Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine, 1 Ohio University Drive Athens, Athens, OH 45701, USA.
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191
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Freitag CM, Strijbis K, van Putten JPM. Host cell binding of the flagellar tip protein of Campylobacter jejuni. Cell Microbiol 2017; 19. [PMID: 28008697 DOI: 10.1111/cmi.12714] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 12/16/2016] [Indexed: 12/29/2022]
Abstract
Flagella are nanofibers that drive bacterial movement. The filaments are generally composed of thousands of tightly packed flagellin subunits with a terminal cap protein, named FliD. Here, we report that the FliD protein of the bacterial pathogen Campylobacter jejuni binds to host cells. Live-cell imaging and confocal microscopy showed initial contact of the bacteria with epithelial cells via the flagella tip. Recombinant FliD protein bound to the surface of intestinal epithelial cells in a dose-dependent fashion. Search for the FliD binding site on the host cell using cells with defined glycosylation defects indicated glycosaminoglycans as a putative target. Heparinase treatment of wild type cells and an excess of soluble heparin abolished FliD binding. Binding assays showed direct and specific binding of FliD to heparin. Addition of an excess of purified FliD or heparin reduced the attachment of viable C. jejuni to the host cells. The host cell binding domain of FliD was mapped to the central region of the protein. Overall, our results indicate that the C. jejuni flagellar tip protein FliD acts as an attachment factor that interacts with cell surface heparan sulfate glycosaminoglycan receptors.
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Affiliation(s)
- Claudia M Freitag
- Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands
| | - Karin Strijbis
- Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands
| | - Jos P M van Putten
- Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands
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192
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Weirich J, Bräutigam C, Mühlenkamp M, Franz-Wachtel M, Macek B, Meuskens I, Skurnik M, Leskinen K, Bohn E, Autenrieth I, Schütz M. Identifying components required for OMP biogenesis as novel targets for antiinfective drugs. Virulence 2017; 8:1170-1188. [PMID: 28118090 PMCID: PMC5711350 DOI: 10.1080/21505594.2016.1278333] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The emergence of multiresistant Gram-negative bacteria requires new therapies for combating bacterial infections. Targeting the biogenesis of virulence factors could be an alternative strategy instead of killing bacteria with antibiotics. The outer membrane (OM) of Gram-negative bacteria acts as a physical barrier. At the same time it facilitates the exchange of molecules and harbors a multitude of proteins associated with virulence. In order to insert proteins into the OM, an essential oligomeric membrane-associated protein complex, the ß-barrel assembly machinery (BAM) is required. Being essential for the biogenesis of outer membrane proteins (OMPs) the BAM and also periplasmic chaperones may serve as attractive targets to develop novel antiinfective agents. Herein, we aimed to elucidate which proteins belonging to the OMP biogenesis machinery have the most important function in granting bacterial fitness, OM barrier function, facilitating biogenesis of dedicated virulence factors and determination of overall virulence. To this end we used the enteropathogen Yersinia enterocolitica as a model system. We individually knocked out all non-essential components of the BAM (BamB, C and E) as well as the periplasmic chaperones DegP, SurA and Skp. In summary, we found that the most profound phenotypes were produced by the loss of BamB or SurA with both knockouts resulting in significant attenuation or even avirulence of Ye in a mouse infection model. Thus, we assume that both BamB and SurA are promising targets for the development of new antiinfective drugs in the future.
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Affiliation(s)
- Johanna Weirich
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Cornelia Bräutigam
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Melanie Mühlenkamp
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | | | - Boris Macek
- b Proteome Center Tübingen, Universität Tübingen , Tübingen , Germany
| | - Ina Meuskens
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Mikael Skurnik
- c Department of Bacteriology and Immunology , Medicum, Research Programs Unit, Immunobiology Research Program, University of Helsinki , Helsinki , Finland
| | - Katarzyna Leskinen
- c Department of Bacteriology and Immunology , Medicum, Research Programs Unit, Immunobiology Research Program, University of Helsinki , Helsinki , Finland
| | - Erwin Bohn
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Ingo Autenrieth
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
| | - Monika Schütz
- a Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum Tübingen , Tübingen , Germany
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193
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The Ruler Protein EscP of the Enteropathogenic Escherichia coli Type III Secretion System Is Involved in Calcium Sensing and Secretion Hierarchy Regulation by Interacting with the Gatekeeper Protein SepL. mBio 2017; 8:mBio.01733-16. [PMID: 28049143 PMCID: PMC5210495 DOI: 10.1128/mbio.01733-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The type III secretion system (T3SS) is a multiprotein complex that plays a central role in the virulence of many Gram-negative bacterial pathogens. To ensure that effector proteins are efficiently translocated into the host cell, bacteria must be able to sense their contact with the host cell. In this study, we found that EscP, which was previously shown to function as the ruler protein of the enteropathogenic Escherichia coli T3SS, is also involved in the switch from the secretion of translocator proteins to the secretion of effector proteins. In addition, we demonstrated that EscP can interact with the gatekeeper protein SepL and that the EscP-SepL complex dissociates upon a calcium concentration drop. We suggest a model in which bacterial contact with the host cell is accompanied by a drop in the calcium concentration that causes SepL-EscP complex dissociation and triggers the secretion of effector proteins. IMPORTANCE The emergence of multidrug-resistant bacterial strains, especially those of pathogenic bacteria, has serious medical and clinical implications. At the same time, the development and approval of new antibiotics have been limited for years. Recently, antivirulence drugs have received considerable attention as a novel antibiotic strategy that specifically targets bacterial virulence rather than growth, an approach that applies milder evolutionary pressure on the bacteria to develop resistance. A highly attractive target for the development of antivirulence compounds is the type III secretion system, a specialized secretory system possessed by many Gram-negative bacterial pathogens for injecting virulence factors (effectors) into host cells. In this study, we shed light on the molecular mechanism that allows bacteria to sense their contact with the host cell and to respond with the timed secretion of effector proteins. Understanding this critical step for bacterial virulence may provide a new therapeutic strategy.
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194
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Diseases of the Alimentary Tract. Vet Med (Auckl) 2017. [PMCID: PMC7167529 DOI: 10.1016/b978-0-7020-5246-0.00007-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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195
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Wang J, Sheng L, Zhao H, Zhang X, Zhang S. Spatiotemporal fluorescence imaging of newly synthesized proteins in normal and cancerous cells with anticarcinogen modulation. Talanta 2017; 162:641-647. [DOI: 10.1016/j.talanta.2016.10.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 09/26/2016] [Accepted: 10/02/2016] [Indexed: 11/25/2022]
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196
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Abstract
Type III secretion (T3S) systems are found in a large number of gram-negative bacteria where they function to manipulate the biology of infected hosts. Hosts targeted by T3S systems are widely distributed in nature and are represented by animals and plants. T3S systems are found in diverse genera of bacteria and they share a common core structure and function. Effector proteins are delivered by T3S systems into targeted host cells without prior secretion of the effectors into the environment. Instead, an assembled translocon structure functions to translocate effectors across eukaryotic cell membranes. In many cases, T3S systems are essential virulence factors and in some instances they promote symbiotic interactions.
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Affiliation(s)
- Danielle L Jessen Condry
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, USA.
| | - Matthew L Nilles
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, USA
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197
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Ho O, Rogne P, Edgren T, Wolf-Watz H, Login FH, Wolf-Watz M. Characterization of the Ruler Protein Interaction Interface on the Substrate Specificity Switch Protein in the Yersinia Type III Secretion System. J Biol Chem 2016; 292:3299-3311. [PMID: 28039361 DOI: 10.1074/jbc.m116.770255] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 12/29/2016] [Indexed: 12/29/2022] Open
Abstract
Many pathogenic Gram-negative bacteria use the type III secretion system (T3SS) to deliver effector proteins into eukaryotic host cells. In Yersinia, the switch to secretion of effector proteins is induced first after intimate contact between the bacterium and its eukaryotic target cell has been established, and the T3SS proteins YscP and YscU play a central role in this process. Here we identify the molecular details of the YscP binding site on YscU by means of nuclear magnetic resonance (NMR) spectroscopy. The binding interface is centered on the C-terminal domain of YscU. Disrupting the YscU-YscP interaction by introducing point mutations at the interaction interface significantly reduced the secretion of effector proteins and HeLa cell cytotoxicity. Interestingly, the binding of YscP to the slowly self-cleaving YscU variant P264A conferred significant protection against autoproteolysis. The YscP-mediated inhibition of YscU autoproteolysis suggests that the cleavage event may act as a timing switch in the regulation of early versus late T3SS substrates. We also show that YscUC binds to the inner rod protein YscI with a dissociation constant (Kd ) of 3.8 μm and with 1:1 stoichiometry. The significant similarity among different members of the YscU, YscP, and YscI families suggests that the protein-protein interactions discussed in this study are also relevant for other T3SS-containing Gram-negative bacteria.
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Affiliation(s)
- Oanh Ho
- Department of Chemistry, Chemical Biological Centre
| | - Per Rogne
- Department of Chemistry, Chemical Biological Centre
| | - Tomas Edgren
- Department of Molecular Biology and The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, S-901 87 Umeå, Sweden
| | - Hans Wolf-Watz
- Department of Molecular Biology and The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, S-901 87 Umeå, Sweden
| | - Frédéric H Login
- Department of Molecular Biology and The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, S-901 87 Umeå, Sweden.
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198
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Metcalf KJ, Bevington JL, Rosales SL, Burdette LA, Valdivia E, Tullman-Ercek D. Proteins adopt functionally active conformations after type III secretion. Microb Cell Fact 2016; 15:213. [PMID: 28010734 PMCID: PMC5180411 DOI: 10.1186/s12934-016-0606-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 11/25/2016] [Indexed: 11/17/2022] Open
Abstract
Background Bacterial production of natively folded heterologous proteins by secretion to the extracellular space can improve protein production by simplifying purification and enabling continuous processing. In a typical bacterial protein production process, the protein of interest accumulates in the cytoplasm of the cell, requiring cellular lysis and extensive purification to separate the desired protein from other cellular constituents. The type III secretion system of Gram-negative bacteria is used to secrete proteins from the cytosol to the extracellular space in one step, but proteins must unfold during translocation, necessitating the folding of secreted proteins in the extracellular space for an efficient production process. We evaluated type III secretion as a protein production strategy by characterizing and quantifying the extent of correct folding after secretion. Results We probed correct folding by assaying the function after secretion of two enzymes—beta-lactamase and alkaline phosphatase—and one single-chain variable fragment of an antibody. Secreted proteins are correctly folded and functional after unfolding, secretion, and refolding in the extracellular space. Furthermore, structural and chemical features required for protein function, such as multimerization and disulfide bond formation, are evident in the secreted protein samples. Finally, the concentration of NaCl in the culture media affects the folding efficiency of secreted proteins in a protein-specific manner. Conclusions In the extracellular space, secreted proteins are able to fold to active conformations, which entails post-translational modifications including: folding, multimerization, acquisition of metal ion cofactors, and formation of disulfide bonds. Further, different proteins have different propensities to refold in the extracellular space and are sensitive to the chemical environment in the extracellular space. Our results reveal strategies to control the secretion and correct folding of diverse target proteins during bacterial cell culture. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0606-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kevin James Metcalf
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - James Lea Bevington
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
| | - Sandy Lisette Rosales
- Department of Nutritional Science and Toxicology, University of California, Berkeley, CA, 94720, USA
| | - Lisa Ann Burdette
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.,Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Elias Valdivia
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
| | - Danielle Tullman-Ercek
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, 60208, USA.
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Jneid B, Moreau K, Plaisance M, Rouaix A, Dano J, Simon S. Role of T3SS-1 SipD Protein in Protecting Mice against Non-typhoidal Salmonella Typhimurium. PLoS Negl Trop Dis 2016; 10:e0005207. [PMID: 27992422 PMCID: PMC5167260 DOI: 10.1371/journal.pntd.0005207] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 10/25/2016] [Indexed: 11/24/2022] Open
Abstract
Background Salmonella enterica species are enteric pathogens that cause severe diseases ranging from self-limiting gastroenteritis to enteric fever and sepsis in humans. These infectious diseases are still the major cause of morbidity and mortality in low-income countries, especially in children younger than 5 years and immunocompromised adults. Vaccines targeting typhoidal diseases are already marketed, but none protect against non-typhoidal Salmonella. The existence of multiple non-typhoidal Salmonella serotypes as well as emerging antibiotic resistance highlight the need for development of a broad-spectrum protective vaccine. All Salmonella spp. utilize two type III Secretion Systems (T3SS 1 and 2) to initiate infection, allow replication in phagocytic cells and induce systemic disease. T3SS-1, which is essential to invade epithelial cells and cross the barrier, forms an extracellular needle and syringe necessary to inject effector proteins into the host cell. PrgI and SipD form, respectively, the T3SS-1 needle and the tip complex at the top of the needle. Because they are common and highly conserved in all virulent Salmonella spp., they might be ideal candidate antigens for a subunit-based, broad-spectrum vaccine. Principal Findings We investigated the immunogenicity and protective efficacy of PrgI and SipD administered by subcutaneous, intranasal and oral routes, alone or combined, in a mouse model of Salmonella intestinal challenge. Robust IgG (in all immunization routes) and IgA (in intranasal and oral immunization routes) antibody responses were induced against both proteins, particularly SipD. Mice orally immunized with SipD alone or SipD combined with PrgI were protected against lethal intestinal challenge with Salmonella Typhimurium (100 Lethal Dose 50%) depending on antigen, route and adjuvant. Conclusions and Significance Salmonella T3SS SipD is a promising antigen for the development of a protective Salmonella vaccine, and could be developed for vaccination in tropical endemic areas to control infant mortality. Salmonella are bacteria responsible for a high global burden of invasive diseases, especially in South and South-East Asia (mainly enteric fever due to Salmonella Typhi) and sub-Saharan Africa (mainly invasive Non-Typhoidal Salmonella, iNTS). This iNTS disease has emerged as a prominent cause of systemic infection in children and immunocompromised African adults, with an associated case fatality of 20–25%. Because licensed vaccines only protect against enteric fever, there is a crucial need to develop a new broad-spectrum vaccine effective against enteric fever and iNTS that can be administered safely to children under 2 years old. The virulence of Salmonella depends on two type III secretion systems (T3SS-1 and T3SS-2) necessary for invasion, replication, intracellular survival and dissemination of the bacteria. Two structural proteins of T3SS-1 (essential for crossing the epithelial barrier) are highly conserved among Salmonella spp. and might be good candidates for a broad-spectrum vaccine. The current study describes the protective effect elicited by these proteins in a murine model. A specific immune response was generated against our antigens and provided protection against Salmonella Typhimurium oral infection. Such a candidate vaccine offers promising perspectives to control Salmonella diseases.
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Affiliation(s)
- Bakhos Jneid
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Karine Moreau
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Marc Plaisance
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Audrey Rouaix
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Julie Dano
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Stéphanie Simon
- Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France
- * E-mail:
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Turab Naqvi AA, Rahman S, Rubi, Zeya F, Kumar K, Choudhary H, Jamal MS, Kim J, Hassan MI. Genome analysis of Chlamydia trachomatis for functional characterization of hypothetical proteins to discover novel drug targets. Int J Biol Macromol 2016; 96:234-240. [PMID: 27993657 DOI: 10.1016/j.ijbiomac.2016.12.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 12/05/2016] [Accepted: 12/15/2016] [Indexed: 01/28/2023]
Abstract
C. trachomatis is a Gram-negative bacterium that causes trachoma and sexually transmitted disease (STD) Chlamydia in humans. Chlamydial genital infections are the most frequent among all communicable diseases. The D/UW-3/Cx strain of C. trachomatis contains 935 genes and three pseudogenes. Out of these genes, 887 genes code for proteins while six for rRNA, 37 tRNA, and three genes translate into other RNAs. The proteome of C. trachomatis made of 887 proteins contains 269 Hypothetical proteins (HPs) that are subjected to functional characterization. This study suggests some known methods of functional characterization of such HPs. All of these methods are explicitly used to assign functions to the HPs with the accuracy of more than 90%. After extensive analysis of all the HPs, we have successfully assigned functions to 89 HPs with high precision. In the newly assigned HPs, there are enzymes, transporters, binding proteins, proteins involved in biosynthesis and regulatory processes and proteins with miscellaneous functions. The study suggests that the functionally annotated HPs may play a vital role in the growth and pathogenesis of this organism. Therefore, they can be considered potential drug targets.
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Affiliation(s)
- Ahmad Abu Turab Naqvi
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Safikur Rahman
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan 712-749, South Korea
| | - Rubi
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Firdaus Zeya
- Department of Computer Science, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Kundan Kumar
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Hani Choudhary
- Department of Biochemistry, Cancer Metabolism and Epigenetic Unit, Faculty of Science, Center of Innovation in Personalized Medicine, Cancer and Mutagenesis Unit, King Fahd Center for Medical Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammad Sarwar Jamal
- King Fahd Medical Research Center, King Abdulaziz University, P.O. Box: 80216, Jeddah 21589, Saudi Arabia
| | - Jihoe Kim
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan 712-749, South Korea.
| | - Md Imtaiyaz Hassan
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
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