1
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Gubensäk N, Sagmeister T, Buhlheller C, Geronimo BD, Wagner GE, Petrowitsch L, Gräwert MA, Rotzinger M, Berger TMI, Schäfer J, Usón I, Reidl J, Sánchez-Murcia PA, Zangger K, Pavkov-Keller T. Vibrio cholerae's ToxRS bile sensing system. eLife 2023; 12:e88721. [PMID: 37768326 PMCID: PMC10624426 DOI: 10.7554/elife.88721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 09/27/2023] [Indexed: 09/29/2023] Open
Abstract
The seventh pandemic of the diarrheal cholera disease, which began in 1960, is caused by the Gram-negative bacterium Vibrio cholerae. Its environmental persistence provoking recurring sudden outbreaks is enabled by V. cholerae's rapid adaption to changing environments involving sensory proteins like ToxR and ToxS. Located at the inner membrane, ToxR and ToxS react to environmental stimuli like bile acid, thereby inducing survival strategies for example bile resistance and virulence regulation. The presented crystal structure of the sensory domains of ToxR and ToxS in combination with multiple bile acid interaction studies, reveals that a bile binding pocket of ToxS is only properly folded upon binding to ToxR. Our data proposes an interdependent functionality between ToxR transcriptional activity and ToxS sensory function. These findings support the previously suggested link between ToxRS and VtrAC-like co-component systems. Besides VtrAC, ToxRS is now the only experimentally determined structure within this recently defined superfamily, further emphasizing its significance. In-depth analysis of the ToxRS complex reveals its remarkable conservation across various Vibrio species, underlining the significance of conserved residues in the ToxS barrel and the more diverse ToxR sensory domain. Unravelling the intricate mechanisms governing ToxRS's environmental sensing capabilities, provides a promising tool for disruption of this vital interaction, ultimately inhibiting Vibrio's survival and virulence. Our findings hold far-reaching implications for all Vibrio strains that rely on the ToxRS system as a shared sensory cornerstone for adapting to their surroundings.
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Affiliation(s)
- Nina Gubensäk
- Institute of Molecular Biosciences, University of GrazGrazAustria
| | - Theo Sagmeister
- Institute of Molecular Biosciences, University of GrazGrazAustria
| | | | - Bruno Di Geronimo
- Laboratory of Computer-Aided Molecular Design, Division of Medicinal Chemistry, Otto-Loewi Research Center, Medical University of GrazGrazAustria
| | - Gabriel E Wagner
- Institute of Chemistry / Organic and Bioorganic Chemistry, Medical University of GrazGrazAustria
- Diagnostic and Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of GrazGrazAustria
| | | | | | - Markus Rotzinger
- Institute of Chemistry / Organic and Bioorganic Chemistry, Medical University of GrazGrazAustria
| | | | | | - Isabel Usón
- Institute of Molecular Biology of BarcelonaBarcelonaSpain
- ICREA, Institució Catalana de Recerca i Estudis AvançatsBarcelonaSpain
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of GrazGrazAustria
- BioHealth Field of Excellence, University of GrazGrazAustria
- BioTechMed-GrazGrazAustria
| | - Pedro A Sánchez-Murcia
- Laboratory of Computer-Aided Molecular Design, Division of Medicinal Chemistry, Otto-Loewi Research Center, Medical University of GrazGrazAustria
| | - Klaus Zangger
- Institute of Chemistry / Organic and Bioorganic Chemistry, Medical University of GrazGrazAustria
- BioHealth Field of Excellence, University of GrazGrazAustria
- BioTechMed-GrazGrazAustria
| | - Tea Pavkov-Keller
- Institute of Molecular Biosciences, University of GrazGrazAustria
- BioHealth Field of Excellence, University of GrazGrazAustria
- BioTechMed-GrazGrazAustria
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2
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Canals A, Pieretti S, Muriel-Masanes M, El Yaman N, Plecha SC, Thomson JJ, Fàbrega-Ferrer M, Pérez-Luque R, Krukonis ES, Coll M. ToxR activates the Vibrio cholerae virulence genes by tethering DNA to the membrane through versatile binding to multiple sites. Proc Natl Acad Sci U S A 2023; 120:e2304378120. [PMID: 37428913 PMCID: PMC10629549 DOI: 10.1073/pnas.2304378120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/31/2023] [Indexed: 07/12/2023] Open
Abstract
ToxR, a Vibrio cholerae transmembrane one-component signal transduction factor, lies within a regulatory cascade that results in the expression of ToxT, toxin coregulated pilus, and cholera toxin. While ToxR has been extensively studied for its ability to activate or repress various genes in V. cholerae, here we present the crystal structures of the ToxR cytoplasmic domain bound to DNA at the toxT and ompU promoters. The structures confirm some predicted interactions, yet reveal other unexpected promoter interactions with implications for other potential regulatory roles for ToxR. We show that ToxR is a versatile virulence regulator that recognizes diverse and extensive, eukaryotic-like regulatory DNA sequences, that relies more on DNA structural elements than specific sequences for binding. Using this topological DNA recognition mechanism, ToxR can bind both in tandem and in a twofold inverted-repeat-driven manner. Its regulatory action is based on coordinated multiple binding to promoter regions near the transcription start site, which can remove the repressing H-NS proteins and prepares the DNA for optimal interaction with the RNA polymerase.
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Affiliation(s)
- Albert Canals
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028Barcelona, Spain
- Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, 08028Barcelona, Spain
| | - Simone Pieretti
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028Barcelona, Spain
- Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, 08028Barcelona, Spain
| | - Mireia Muriel-Masanes
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028Barcelona, Spain
- Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, 08028Barcelona, Spain
| | - Nour El Yaman
- Department of Biology, University of Detroit Mercy, Detroit, MI48221
| | - Sarah C. Plecha
- Division of Integrated Biomedical Sciences, University of Detroit Mercy School of Dentistry, Detroit, MI48208
| | - Joshua J. Thomson
- Division of Integrated Biomedical Sciences, University of Detroit Mercy School of Dentistry, Detroit, MI48208
| | - Montserrat Fàbrega-Ferrer
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028Barcelona, Spain
- Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, 08028Barcelona, Spain
| | - Rosa Pérez-Luque
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028Barcelona, Spain
- Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, 08028Barcelona, Spain
| | - Eric S. Krukonis
- Division of Integrated Biomedical Sciences, University of Detroit Mercy School of Dentistry, Detroit, MI48208
| | - Miquel Coll
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028Barcelona, Spain
- Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, 08028Barcelona, Spain
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3
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Midgett CR, Kull FJ. Structural Insights into Regulation of Vibrio Virulence Gene Networks. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:269-294. [PMID: 36792881 DOI: 10.1007/978-3-031-22997-8_14] [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: 02/17/2023]
Abstract
One of the best studied aspects of pathogenic Vibrios are the virulence cascades that lead to the production of virulence factors and, ultimately, clinical outcomes. In this chapter, we will examine the regulation of Vibrio virulence gene networks from a structural and biochemical perspective. We will discuss the recent research into the numerous proteins that contribute to regulating virulence in Vibrio spp such as quorum sensing regulator HapR, the transcription factors AphA and AphB, or the virulence regulators ToxR and ToxT. We highlight how insights gained from these studies are already illuminating the basic molecular mechanisms by which the virulence cascade of pathogenic Vibrios unfold and contend that understanding how protein interactions contribute to the host-pathogen communications will enable the development of new antivirulence compounds that can effectively target these pathogens.
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Affiliation(s)
| | - F Jon Kull
- Chemistry Department, Dartmouth College, Hanover, NH, USA.
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4
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Šoltysová M, Sieglová I, Fábry M, Brynda J, Škerlová J, Řezáčová P. Structural insight into DNA recognition by bacterial transcriptional regulators of the SorC/DeoR family. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2021; 77:1411-1424. [PMID: 34726169 DOI: 10.1107/s2059798321009633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/16/2021] [Indexed: 11/11/2022]
Abstract
The SorC/DeoR family is a large family of bacterial transcription regulators that are involved in the control of carbohydrate metabolism and quorum sensing. To understand the structural basis of DNA recognition, structural studies of two functionally characterized SorC/DeoR family members from Bacillus subtilis were performed: the deoxyribonucleoside regulator bsDeoR and the central glycolytic genes regulator bsCggR. Each selected protein represents one of the subgroups that are recognized within the family. Crystal structures were determined of the N-terminal DNA-binding domains of bsDeoR and bsCggR in complex with DNA duplexes representing the minimal operator sequence at resolutions of 2.3 and 2.1 Å, respectively. While bsDeoRDBD contains a homeodomain-like HTH-type domain, bsCggRDBD contains a winged helix-turn-helix-type motif. Both proteins form C2-symmetric dimers that recognize two consecutive major grooves, and the protein-DNA interactions have been analyzed in detail. The crystal structures were used to model the interactions of the proteins with the full DNA operators, and a common mode of DNA recognition is proposed that is most likely to be shared by other members of the SorC/DeoR family.
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Affiliation(s)
- Markéta Šoltysová
- Structural Biology, Institute of Organic Chemistry and Biochemistry of Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic
| | - Irena Sieglová
- Structural Biology, Institute of Organic Chemistry and Biochemistry of Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic
| | - Milan Fábry
- Institute of Molecular Genetics of Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic
| | - Jiří Brynda
- Structural Biology, Institute of Organic Chemistry and Biochemistry of Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic
| | - Jana Škerlová
- Structural Biology, Institute of Organic Chemistry and Biochemistry of Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic
| | - Pavlína Řezáčová
- Structural Biology, Institute of Organic Chemistry and Biochemistry of Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic
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5
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Structure, regulation, and host interaction of outer membrane protein U (OmpU) of Vibrio species. Microb Pathog 2021; 162:105267. [PMID: 34718127 DOI: 10.1016/j.micpath.2021.105267] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/30/2021] [Accepted: 10/20/2021] [Indexed: 01/22/2023]
Abstract
OmpU is a multimeric, cation selective outer membrane protein of Vibrio and related species that non-covalently interact with peptidoglycan layer. Interaction of OmpU with human host cells triggers signaling pathways to promote cytokine secretion, reactive oxygen species production, and caspase independent death in immune and epithelial cells. Non-choleric OmpU imparts resistance to antimicrobial peptides and induces actin cytoskeletal reorganization in the host cells. Further, OmpU isolated from Vibrio species elicits an immune response in several aquaculture hosts. Importantly, in-vivo studies using recombinant OmpU or OmpU derived mimotopes reveal a short-lasting immunity, and protection against Vibrio in the aquaculture sector. In conclusion, OmpU is a key adhesion protein and an important virulence factor for successful colonization of Vibrio species into hosts. This review article provides a broad overview of structural, regulatory, and functional mechanisms of OmpU in normal and disease states.
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6
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Structural and DNA-binding properties of the cytoplasmic domain of Vibrio cholerae transcription factor ToxR. J Biol Chem 2021; 297:101167. [PMID: 34487759 PMCID: PMC8517210 DOI: 10.1016/j.jbc.2021.101167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 08/26/2021] [Accepted: 09/02/2021] [Indexed: 11/21/2022] Open
Abstract
ToxR represents an essential transcription factor of Vibrio cholerae, which is involved in the regulation of multiple, mainly virulence associated genes. Its versatile functionality as activator, repressor or coactivator suggests a complex regulatory mechanism, whose clarification is essential for a better understanding of the virulence expression system of V. cholerae. Here, we provide structural information elucidating the organization and binding behavior of the cytoplasmic DNA-binding domain of ToxR (cToxR), containing a winged helix–turn–helix (wHTH) motif. Our analysis reveals unexpected structural features of this domain expanding our knowledge of a poorly defined subfamily of wHTH proteins. cToxR forms an extraordinary long α-loop and furthermore has an additional C-terminal beta strand, contacting the N-terminus and thus leading to a compact fold. The identification of the exact interactions between ToxR and DNA contributes to a deeper understanding of this regulatory process. Our findings not only show general binding of the soluble cytoplasmic domain of ToxR to DNA, but also indicate a higher affinity for the toxT motif. These results support the current theory of ToxR being a “DNA-catcher” to enable binding of the transcription factor TcpP and thus activation of virulence-associated toxT transcription. Although, TcpP and ToxR interaction is assumed to be crucial in the activation of the toxT genes, we could not detect an interaction event of their isolated cytoplasmic domains. We therefore conclude that other factors are needed to establish this protein–protein interaction, e.g., membrane attachment, the presence of their full-length proteins and/or other intermediary proteins that may facilitate binding.
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7
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Deng C, Lv X, Li J, Zhang H, Liu Y, Du G, Amaro RL, Liu L. Synergistic improvement of N-acetylglucosamine production by engineering transcription factors and balancing redox cofactors. Metab Eng 2021; 67:330-346. [PMID: 34329707 DOI: 10.1016/j.ymben.2021.07.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/29/2021] [Accepted: 07/26/2021] [Indexed: 12/17/2022]
Abstract
The regulation of single gene transcription level in the metabolic pathway is often failed to significantly improve the titer of the target product, and even leads to the imbalance of carbon/nitrogen metabolic network and cofactor network. Global transcription machinery engineering (gTME) can activate or inhibit the synergistic expression of multiple genes in specific metabolic pathways, so transcription factors with specific functions can be expressed according to different metabolic regulation requirements, thus effectively increasing the synthesis of target metabolites. In addition, maintaining intracellular redox balance through cofactor engineering can realize the self-balance of cofactors and promote the efficient synthesis of target products. In this study, we rebalanced the central carbon/nitrogen metabolism and redox metabolism of Corynebacterium glutamicum S9114 by gTME and redox cofactors engineering to promote the production of the nutraceutical N-acetylglucosamine (GlcNAc). Firstly, it was found that the overexpression of the transcription factor RamA can promote GlcNAc synthesis, and the titer was further improved to 16 g/L in shake flask by using a mutant RamA (RamAM). Secondly, a CRISPR interference (CRISPRi) system based on dCpf1 was developed and used to inhibit the expression of global negative transcriptional regulators of GlcNAc synthesis, which promoted the GlcNAc titer to 27.5 g/L. Thirdly, the cofactor specificity of the key enzymes in GlcNAc synthesis pathway was changed by rational protein engineering, and the titer of GlcNAc in shake flask was increased to 36.9 g/L. Finally, the production of GlcNAc was scaled up in a 50-L fermentor, and the titer reached 117.1 ± 1.9 g/L, which was 6.62 times that of the control group (17.7 ± 0.4 g/L), and the yield was increased from 0.19 g/g to 0.31 g/g glucose. The results obtained here highlight the importance of engineering the global regulation of central carbon/nitrogen metabolism and redox metabolism to improve the production performance of microbial cell factories.
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Affiliation(s)
- Chen Deng
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; Science Center for Future Foods, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Xueqin Lv
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; Science Center for Future Foods, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Jianghua Li
- Science Center for Future Foods, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Hongzhi Zhang
- Shandong Runde Biotechnology Co, Ltd, Tai'an, 271000, China
| | - Yanfeng Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; Science Center for Future Foods, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Guocheng Du
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Rodrigo Ledesma Amaro
- Department of Bioengineering and Imperial College Centre for Synthetic Biology, Imperial College London, London, SW72AZ, UK
| | - Long Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; Science Center for Future Foods, Ministry of Education, Jiangnan University, Wuxi, 214122, China.
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8
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Pennetzdorfer N, Höfler T, Wölflingseder M, Tutz S, Schild S, Reidl J. σ E controlled regulation of porin OmpU in Vibrio cholerae. Mol Microbiol 2021; 115:1244-1261. [PMID: 33330989 PMCID: PMC8359247 DOI: 10.1111/mmi.14669] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 12/11/2020] [Accepted: 12/11/2020] [Indexed: 01/19/2023]
Abstract
Bile resistance is essential for enteric pathogens, as exemplified by Vibrio cholerae, the causative agent of cholera. The outer membrane porin OmpU confers bacterial survival and colonization advantages in the presence of host‐derived antimicrobial peptides as well as bile. Expression of ompU is controlled by the virulence regulator ToxR. rpoE knockouts are accompanied by suppressor mutations causing ompU downregulation. Therefore, OmpU constitutes an intersection of the ToxR regulon and the σE‐pathway in V. cholerae. To understand the mechanism by which the sigma factor σE regulates OmpU synthesis, we performed transcription studies using ompU reporter fusions and immunoblot analysis. Our data revealed an increase in ompU promoter activity in ΔrpoE strains, as well as in a ΔompU background, indicating a negative feedback regulation circuit of ompU expression. This regulation seems necessary, since elevated lethality rates of ΔrpoE strains occur upon ompU overexpression. Manipulation of OmpU’s C‐terminal portion revealed its relevance for protein stability and potency of σE release. Furthermore, ΔrpoE strains are still capable of elevating OmpU levels under membrane stress conditions triggered by the bile salt sodium deoxycholate. This study provides new details about the impact of σE on ompU regulation, which is critical to the pathogen’s intestinal survival.
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Affiliation(s)
| | - Thomas Höfler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Sarah Tutz
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Stefan Schild
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth, University of Graz, Graz, Austria
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9
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Ramamurthy T, Nandy RK, Mukhopadhyay AK, Dutta S, Mutreja A, Okamoto K, Miyoshi SI, Nair GB, Ghosh A. Virulence Regulation and Innate Host Response in the Pathogenicity of Vibrio cholerae. Front Cell Infect Microbiol 2020; 10:572096. [PMID: 33102256 PMCID: PMC7554612 DOI: 10.3389/fcimb.2020.572096] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023] Open
Abstract
The human pathogen Vibrio cholerae is the causative agent of severe diarrheal disease known as cholera. Of the more than 200 "O" serogroups of this pathogen, O1 and O139 cause cholera outbreaks and epidemics. The rest of the serogroups, collectively known as non-O1/non-O139 cause sporadic moderate or mild diarrhea and also systemic infections. Pathogenic V. cholerae circulates between nutrient-rich human gut and nutrient-deprived aquatic environment. As an autochthonous bacterium in the environment and as a human pathogen, V. cholerae maintains its survival and proliferation in these two niches. Growth in the gastrointestinal tract involves expression of several genes that provide bacterial resistance against host factors. An intricate regulatory program involving extracellular signaling inputs is also controlling this function. On the other hand, the ability to store carbon as glycogen facilitates bacterial fitness in the aquatic environment. To initiate the infection, V. cholerae must colonize the small intestine after successfully passing through the acid barrier in the stomach and survive in the presence of bile and antimicrobial peptides in the intestinal lumen and mucus, respectively. In V. cholerae, virulence is a multilocus phenomenon with a large functionally associated network. More than 200 proteins have been identified that are functionally linked to the virulence-associated genes of the pathogen. Several of these genes have a role to play in virulence and/or in functions that have importance in the human host or the environment. A total of 524 genes are differentially expressed in classical and El Tor strains, the two biotypes of V. cholerae serogroup O1. Within the host, many immune and biological factors are able to induce genes that are responsible for survival, colonization, and virulence. The innate host immune response to V. cholerae infection includes activation of several immune protein complexes, receptor-mediated signaling pathways, and other bactericidal proteins. This article presents an overview of regulation of important virulence factors in V. cholerae and host response in the context of pathogenesis.
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Affiliation(s)
| | - Ranjan K Nandy
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Asish K Mukhopadhyay
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Shanta Dutta
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Ankur Mutreja
- Global Health-Infectious Diseases, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Keinosuke Okamoto
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.,Collaborative Research Center of Okayama University for Infectious Diseases in India, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Shin-Ichi Miyoshi
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - G Balakrish Nair
- Microbiome Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
| | - Amit Ghosh
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
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10
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Lembke M, Höfler T, Walter AN, Tutz S, Fengler V, Schild S, Reidl J. Host stimuli and operator binding sites controlling protein interactions between virulence master regulator ToxR and ToxS in Vibrio cholerae. Mol Microbiol 2020; 114:262-278. [PMID: 32251547 PMCID: PMC7496328 DOI: 10.1111/mmi.14510] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 02/06/2023]
Abstract
Protein-protein interactions (PPIs) are key mechanisms in the maintenance of biological regulatory networks. Herein, we characterize PPIs within ToxR and its co-activator, ToxS, to understand the mechanisms of ToxR transcription factor activation. ToxR is a key transcription activator that is supported by ToxS for virulence gene regulation in Vibrio cholerae. ToxR comprises a cytoplasmic DNA-binding domain that is linked by a transmembrane domain to a periplasmic signal receiver domain containing two cysteine residues. ToxR-ToxR and ToxR-ToxS PPIs were detected using an adenylate-cyclase-based bacterial two-hybrid system approach in Escherichia coli. We found that the ToxR-ToxR PPIs are significantly increased in response to ToxR operators, the co-activator ToxS and bile salts. We suggest that ToxS and bile salts promote the interaction between ToxR molecules that ultimately results in dimerization. Upon binding of operators, ToxR-ToxR PPIs are found at the highest frequency. Moreover, disulfide-bond-dependent interaction in the periplasm results in homodimer formation that is promoted by DNA binding. The formation of these homodimers and the associated transcriptional activity of ToxR were strongly dependent on the oxidoreductases DsbA/DsbC. These findings show that protein and non-protein partners, that either transiently or stably interact with ToxR, fine-tune ToxR PPIs, and its associated transcriptional activity in changing environments.
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Affiliation(s)
- Mareike Lembke
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Thomas Höfler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | | | - Sarah Tutz
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Vera Fengler
- Division of Physiological Chemistry, Medical University of Graz, Graz, Austria
| | - Stefan Schild
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,BioHealth, University of Graz, Graz, Austria
| | - Joachim Reidl
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,BioHealth, University of Graz, Graz, Austria
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