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VanZeeland NE, Schultz KM, Klug CS, Kristich CJ. Multisite Phosphorylation Regulates GpsB Function in Cephalosporin Resistance of Enterococcus faecalis. J Mol Biol 2023; 435:168216. [PMID: 37517789 PMCID: PMC10528945 DOI: 10.1016/j.jmb.2023.168216] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
Enterococci are normal human commensals and major causes of hospital-acquired infections. Enterococcal infections can be difficult to treat because enterococci harbor intrinsic and acquired antibiotic resistance, such as resistance to cephalosporins. In Enterococcus faecalis, the transmembrane kinase IreK, a member of the bacterial PASTA kinase family, is essential for cephalosporin resistance. The activity of IreK is boosted by the cytoplasmic protein GpsB, which promotes IreK autophosphorylation and signaling to drive cephalosporin resistance. A previous phosphoproteomics study identified eight putative IreK-dependent phosphorylation sites on GpsB, but the functional importance of GpsB phosphorylation was unknown. Here we used genetic and biochemical approaches to define three sites of phosphorylation on GpsB that functionally impact IreK activity and cephalosporin resistance. Phosphorylation at two sites (S80 and T84) serves to impair the ability of GpsB to activate IreK in vivo, suggesting phosphorylation of these sites acts as a means of negative feedback for IreK. The third site of phosphorylation (T133) occurs in a segment of GpsB termed the C-terminal extension that is unique to enterococcal GpsB homologs. The C-terminal extension is highly mobile in solution, suggesting it is largely unstructured, and phosphorylation of T133 appears to enable efficient phosphorylation at S80 / T84. Overall our results are consistent with a model in which multisite phosphorylation of GpsB impairs its ability to activate IreK, thereby diminishing signal transduction through the IreK-dependent pathway and modulating phenotypic cephalosporin resistance.
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Affiliation(s)
- Nicole E VanZeeland
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA
| | - Kathryn M Schultz
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA
| | - Candice S Klug
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA
| | - Christopher J Kristich
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA.
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2
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Tang J, Guo M, Chen M, Xu B, Ran T, Wang W, Ma Z, Lin H, Fan H. A link between STK signalling and capsular polysaccharide synthesis in Streptococcus suis. Nat Commun 2023; 14:2480. [PMID: 37120581 PMCID: PMC10148854 DOI: 10.1038/s41467-023-38210-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 04/20/2023] [Indexed: 05/01/2023] Open
Abstract
Synthesis of capsular polysaccharide (CPS), an important virulence factor of pathogenic bacteria, is modulated by the CpsBCD phosphoregulatory system in Streptococcus. Serine/threonine kinases (STKs, e.g. Stk1) can also regulate CPS synthesis, but the underlying mechanisms are unclear. Here, we identify a protein (CcpS) that is phosphorylated by Stk1 and modulates the activity of phosphatase CpsB in Streptococcus suis, thus linking Stk1 to CPS synthesis. The crystal structure of CcpS shows an intrinsically disordered region at its N-terminus, including two threonine residues that are phosphorylated by Stk1. The activity of phosphatase CpsB is inhibited when bound to non-phosphorylated CcpS. Thus, CcpS modulates the activity of phosphatase CpsB thereby altering CpsD phosphorylation, which in turn modulates the expression of the Wzx-Wzy pathway and thus CPS production.
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Affiliation(s)
- Jinsheng Tang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Mengru Guo
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Min Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Bin Xu
- National Research Center of Veterinary Biologicals Engineering and Technology, Jiangsu Academy of Agricultural Sciences, Nanjing, 210000, China
| | - Tingting Ran
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Weiwu Wang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhe Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
- Jiangsu Coinnovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China
| | - Huixing Lin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
- Jiangsu Coinnovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
- Jiangsu Coinnovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.
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3
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GpsB Promotes PASTA Kinase Signaling and Cephalosporin Resistance in Enterococcus faecalis. J Bacteriol 2022; 204:e0030422. [PMID: 36094306 PMCID: PMC9578390 DOI: 10.1128/jb.00304-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Enterococci are opportunistic pathogens that can cause severe bacterial infections. Treatment of these infections is challenging because enterococci possess intrinsic and acquired mechanisms of resistance to commonly used antibiotics, including cephalosporins. The transmembrane serine/threonine PASTA kinase, IreK, is an important determinant of enterococcal cephalosporin resistance. Upon exposure to cephalosporins, IreK becomes autophosphorylated, which stimulates its kinase activity to phosphorylate downstream substrates and drive cephalosporin resistance. However, the molecular mechanisms that modulate IreK autophosphorylation in response to cell wall stress, such as that induced by cephalosporins, remain unknown. A cytoplasmic protein, GpsB, promotes signaling by PASTA kinase homologs in other bacterial species, but the function of enterococcal GpsB has not been previously investigated. We used in vitro and in vivo approaches to test the hypothesis that enterococcal GpsB promotes IreK signaling in response to cephalosporins to drive cephalosporin resistance. We found that GpsB promotes IreK activity both in vivo and in vitro. This effect is required for cephalosporins to trigger IreK autophosphorylation and activation of an IreK-dependent signaling pathway, and thereby is also required for enterococcal intrinsic cephalosporin resistance. Moreover, analyses of GpsB mutants and a ΔireK gpsB double mutant suggest that GpsB has an additional function, beyond regulation of IreK activity, which is required for optimal growth and full cephalosporin resistance. Collectively, our data provide new insights into the mechanism of signal transduction by the PASTA kinase IreK and the mechanism of enterococcal intrinsic cephalosporin resistance. IMPORTANCE Enterococci are opportunistic pathogens that can cause severe bacterial infections. Treatment of these infections is challenging because enterococci possess intrinsic and acquired resistance to commonly used antibiotics. In particular, enterococci are intrinsically resistant to cephalosporin antibiotics, a trait that requires the activity of a transmembrane serine/threonine kinase, IreK, which belongs to the bacterial PASTA kinase family. The mechanisms by which PASTA kinases are regulated in cells are poorly understood. Here, we report that the cytoplasmic protein GpsB directly promotes IreK signaling in enterococci to drive cephalosporin resistance. Thus, we provide new insights into PASTA kinase regulation and control of enterococcal cephalosporin resistance, and suggest that GpsB could be a promising target for new therapeutics to disable cephalosporin resistance.
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Garcia-Garcia T, Douché T, Giai Gianetto Q, Poncet S, El Omrani N, Smits WK, Cuenot E, Matondo M, Martin-Verstraete I. In-Depth Characterization of the Clostridioides difficile Phosphoproteome to Identify Ser/Thr Kinase Substrates. Mol Cell Proteomics 2022; 21:100428. [PMID: 36252736 PMCID: PMC9674922 DOI: 10.1016/j.mcpro.2022.100428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 09/13/2022] [Accepted: 10/13/2022] [Indexed: 11/17/2022] Open
Abstract
Clostridioides difficile is the leading cause of postantibiotic diarrhea in adults. During infection, the bacterium must rapidly adapt to the host environment by using survival strategies. Protein phosphorylation is a reversible post-translational modification employed ubiquitously for signal transduction and cellular regulation. Hanks-type serine/threonine kinases (STKs) and serine/threonine phosphatases have emerged as important players in bacterial cell signaling and pathogenicity. C. difficile encodes two STKs (PrkC and CD2148) and one phosphatase. We optimized a titanium dioxide phosphopeptide enrichment approach to determine the phosphoproteome of C. difficile. We identified and quantified 2500 proteins representing 63% of the theoretical proteome. To identify STK and serine/threonine phosphatase targets, we then performed comparative large-scale phosphoproteomics of the WT strain and isogenic ΔprkC, CD2148, Δstp, and prkC CD2148 mutants. We detected 635 proteins containing phosphorylated peptides. We showed that PrkC is phosphorylated on multiple sites in vivo and autophosphorylates in vitro. We were unable to detect a phosphorylation for CD2148 in vivo, whereas this kinase was phosphorylated in vitro only in the presence of PrkC. Forty-one phosphoproteins were identified as phosphorylated under the control of CD2148, whereas 114 proteins were phosphorylated under the control of PrkC including 27 phosphoproteins more phosphorylated in the ∆stp mutant. We also observed enrichment for phosphothreonine among the phosphopeptides more phosphorylated in the Δstp mutant. Both kinases targeted pathways required for metabolism, translation, and stress response, whereas cell division and peptidoglycan metabolism were more specifically controlled by PrkC-dependent phosphorylation in agreement with the phenotypes of the ΔprkC mutant. Using a combination of approaches, we confirmed that FtsK was phosphorylated in vivo under the control of PrkC and that Spo0A was a substrate of PrkC in vitro. This study provides a detailed mapping of kinase-substrate relationships in C. difficile, paving the way for the identification of new biomarkers and therapeutic targets.
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Affiliation(s)
- Transito Garcia-Garcia
- Laboratoire Pathogénese des Bactéries Anaérobies, UMR CNRS 6047, Institut Pasteur, Université Paris Cité, Paris, France
| | - Thibaut Douché
- Plateforme Protéomique, Unité de Technologie et Service Spectrométrie de Masse pour la biologie, CNRS USR 2000, Institut Pasteur, Université Paris Cité, Paris, France
| | - Quentin Giai Gianetto
- Plateforme Protéomique, Unité de Technologie et Service Spectrométrie de Masse pour la biologie, CNRS USR 2000, Institut Pasteur, Université Paris Cité, Paris, France,Hub de bioinformatique et biostatistiques, Departement de Biologie computationelle, Institut Pasteur, Université Paris Cité, Paris, France
| | - Sandrine Poncet
- INRAE, AgroParisTech, Micalis Institute, Université Paris-Saclay, Jouy-en-Josas, France
| | - Nesrine El Omrani
- Plateforme Protéomique, Unité de Technologie et Service Spectrométrie de Masse pour la biologie, CNRS USR 2000, Institut Pasteur, Université Paris Cité, Paris, France
| | - Wiep Klaas Smits
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Elodie Cuenot
- Laboratoire Pathogénese des Bactéries Anaérobies, UMR CNRS 6047, Institut Pasteur, Université Paris Cité, Paris, France
| | - Mariette Matondo
- Plateforme Protéomique, Unité de Technologie et Service Spectrométrie de Masse pour la biologie, CNRS USR 2000, Institut Pasteur, Université Paris Cité, Paris, France,For correspondence: Isabelle Martin-Verstraete; Mariette Matondo
| | - Isabelle Martin-Verstraete
- Laboratoire Pathogénese des Bactéries Anaérobies, UMR CNRS 6047, Institut Pasteur, Université Paris Cité, Paris, France,Institut Universitaire de France, Paris, France,For correspondence: Isabelle Martin-Verstraete; Mariette Matondo
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5
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Li H, Li T, Hu Q, Yao Z, Li L, Huang Q, Zhou R. Inhibitors targeting the autophosphorylation of serine/threonine kinase of Streptococcus suis show potent antimicrobial activity. Front Microbiol 2022; 13:990091. [PMID: 36118193 PMCID: PMC9478340 DOI: 10.3389/fmicb.2022.990091] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/09/2022] [Indexed: 11/19/2022] Open
Abstract
Antimicrobial resistance (AMR) is a global concern threatening public health. Developing novel antibiotics is one of the effective strategies to tackle AMR. Serine/threonine kinases (STKs) have been recently shown to play critical roles in the physiology and pathogenesis of several important bacterial pathogens which are regarded as a promising antimicrobial drug target. We previously reported the roles of STK in the regulation of bacterial cell division, metabolism, and pathogenesis in Streptococcus suis, an important zoonotic bacterial pathogen. In this study, we firstly identified the Thr167 and Ser175 residues in the activation loop of S. suis STK (ssSTK) as the kinase autophosphorylation sites. Phenotyping results demonstrated that the autophosphorylation deficient strain resembled the stk deletion strain showing essentiality for bacterial growth in minimal medium, abnormal morphology, and decreased virulence when compared with the wild-type S. suis SC19 strain. Based on these findings, we established an ssSTK inhibitor screening approach by measuring the growth of S. suis in a minimal medium and testing the autophosphorylation inhibition by measuring the consumption of ATP in an enzymatic reaction by ssSTK. A series of inhibitors against ssSTK are identified from a commercial kinase inhibitors library, including Staurosporine, K252a, AT9283, and APY29. These inhibitors showed antimicrobial activity in vitro. Moreover, by using Galleria mellonella larvae infection assay, compound APY29 displayed in vivo efficacy against S. suis infection. Additionally, it was predicted by molecular docking that these inhibitors could interact with ssSTK. Collectively, our data illustrated the essential roles of ssSTK autophosphorylation in the physiology and pathogenicity of S. suis and consider these inhibitors as promising antimicrobial lead compounds.
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Affiliation(s)
- Haotian Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Tingting Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Qiao Hu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Zhiming Yao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Lu Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Cooperative Innovation Center of Sustainable Pig Production, Wuhan, China
- International Research Center for Animal Disease (Ministry of Science & Technology of China), Wuhan, China
| | - Qi Huang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Cooperative Innovation Center of Sustainable Pig Production, Wuhan, China
- International Research Center for Animal Disease (Ministry of Science & Technology of China), Wuhan, China
- *Correspondence: Qi Huang,
| | - Rui Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Cooperative Innovation Center of Sustainable Pig Production, Wuhan, China
- International Research Center for Animal Disease (Ministry of Science & Technology of China), Wuhan, China
- The HZAU-HVSEN Institute, Wuhan, China
- Rui Zhou,
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6
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Nagarajan SN, Lenoir C, Grangeasse C. Recent advances in bacterial signaling by serine/threonine protein kinases. Trends Microbiol 2021; 30:553-566. [PMID: 34836791 DOI: 10.1016/j.tim.2021.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 11/27/2022]
Abstract
It has been nearly three decades since the discovery of the first bacterial serine/threonine protein kinase (STPK). Since then, a blend of technological advances has led to the characterization of a multitude of STPKs and phosphorylation substrates in several bacterial species that finely regulate intricate signaling cascades. Years of intense research from several laboratories have demonstrated unexpected roles for serine/threonine phosphorylation, regulating not only bacterial growth and cell division but also antibiotic persistence, virulence and infection, metabolism, chromosomal biology, and cellular differentiation. This review aims to provide an account of the most recent and significant developments in this up and growing field in microbiology.
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Affiliation(s)
- Sathya Narayanan Nagarajan
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université de Lyon, CNRS, IBCP building, 7 passage du Vercors, 69367 Lyon Cedex 07, France
| | - Cassandra Lenoir
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université de Lyon, CNRS, IBCP building, 7 passage du Vercors, 69367 Lyon Cedex 07, France
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université de Lyon, CNRS, IBCP building, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
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7
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Iannetta AA, Minton NE, Uitenbroek AA, Little JL, Stanton CR, Kristich CJ, Hicks LM. IreK-Mediated, Cell Wall-Protective Phosphorylation in Enterococcus faecalis. J Proteome Res 2021; 20:5131-5144. [PMID: 34672600 PMCID: PMC10037947 DOI: 10.1021/acs.jproteome.1c00635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Enterococcus faecalis is a Gram-positive bacterium that is a major cause of hospital-acquired infections due, in part, to its intrinsic resistance to cell wall-active antimicrobials. One critical determinant of this resistance is the transmembrane kinase IreK, which belongs to the penicillin-binding protein and serine/threonine kinase-associated kinase family of bacterial signaling proteins involved with the regulation of cell wall homeostasis. The activity of IreK is enhanced in response to cell wall stress, but direct substrates of IreK phosphorylation, leading to antimicrobial resistance, are largely unknown. To better understand stress-modulated phosphorylation events contributing to antimicrobial resistance, wild type E. faecalis cells treated with cell wall-active antimicrobials, chlorhexidine or ceftriaxone, were examined via phosphoproteomics. Among the most prominent changes was increased phosphorylation of divisome components after both treatments, suggesting that E. faecalis modulates cell division in response to cell wall stress. Phosphorylation mediated by IreK was then determined via a similar analysis with a E. faecalis ΔireK mutant strain, revealing potential IreK substrates involved with the regulation of peptidoglycan biosynthesis and within the E. faecalis CroS/R two-component system, another signal transduction pathway that promotes antimicrobial resistance. These results reveal critical insights into the biological functions of IreK.
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Affiliation(s)
- Anthony A. Iannetta
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Nicole E. Minton
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Alexis A. Uitenbroek
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Jaime L. Little
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Caroline R. Stanton
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Christopher J. Kristich
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Leslie M. Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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8
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Ramos Y, Sansone S, Morales DK. Sugarcoating it: Enterococcal polysaccharides as key modulators of host-pathogen interactions. PLoS Pathog 2021; 17:e1009822. [PMID: 34499702 PMCID: PMC8428557 DOI: 10.1371/journal.ppat.1009822] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Yusibeska Ramos
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, New York, United States of America
| | - Stephanie Sansone
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, New York, United States of America
- Department of Urology, Weill Cornell Medicine, New York, New York, United States of America
| | - Diana K. Morales
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, New York, United States of America
- * E-mail:
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9
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Ducret A, Grangeasse C. Recent progress in our understanding of peptidoglycan assembly in Firmicutes. Curr Opin Microbiol 2021; 60:44-50. [PMID: 33588129 DOI: 10.1016/j.mib.2021.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/13/2021] [Accepted: 01/27/2021] [Indexed: 02/06/2023]
Abstract
Years of intense research have shown that the assembly of peptidoglycan, the extracellular mesh-like polymer surrounding the bacterial cell, is incredibly complex. It requires a suite of reactions catalyzed by dynamic macromolecular protein complexes whose localization and activity should be finely regulated in space and time. In this review, we focus on the main developments reported over the last five years for the assembly of peptidoglycan in Firmicutes, a bacterial phylum that comprises monoderm bacteria and that encompasses well studied bacterial models with different cell shapes and lifestyles.
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Affiliation(s)
- Adrien Ducret
- Molecular Microbiology and Structural Biochemistry, CNRS UMR 5086, Université de Lyon, 7 passage du Vercors, 69367 Lyon, France
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry, CNRS UMR 5086, Université de Lyon, 7 passage du Vercors, 69367 Lyon, France.
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10
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Chatterjee A, Willett JLE, Dunny GM, Duerkop BA. Phage infection and sub-lethal antibiotic exposure mediate Enterococcus faecalis type VII secretion system dependent inhibition of bystander bacteria. PLoS Genet 2021; 17:e1009204. [PMID: 33411815 PMCID: PMC7790226 DOI: 10.1371/journal.pgen.1009204] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/08/2020] [Indexed: 02/07/2023] Open
Abstract
Bacteriophages (phages) are being considered as alternative therapeutics for the treatment of multidrug resistant bacterial infections. Considering phages have narrow host-ranges, it is generally accepted that therapeutic phages will have a marginal impact on non-target bacteria. We have discovered that lytic phage infection induces transcription of type VIIb secretion system (T7SS) genes in the pathobiont Enterococcus faecalis. Membrane damage during phage infection induces T7SS gene expression resulting in cell contact dependent antagonism of different Gram positive bystander bacteria. Deletion of essB, a T7SS structural component, abrogates phage-mediated killing of bystanders. A predicted immunity gene confers protection against T7SS mediated inhibition, and disruption of its upstream LXG toxin gene rescues growth of E. faecalis and Staphylococcus aureus bystanders. Phage induction of T7SS gene expression and bystander inhibition requires IreK, a serine/threonine kinase, and OG1RF_11099, a predicted GntR-family transcription factor. Additionally, sub-lethal doses of membrane targeting and DNA damaging antibiotics activated T7SS expression independent of phage infection, triggering T7SS antibacterial activity against bystander bacteria. Our findings highlight how phage infection and antibiotic exposure of a target bacterium can affect non-target bystander bacteria and implies that therapies beyond antibiotics, such as phage therapy, could impose collateral damage to polymicrobial communities. Renewed interest in phages as alternative therapeutics to combat multi-drug resistant bacterial infections, highlights the importance of understanding the consequences of phage-bacteria interactions in the context of microbial communities. Although it is well established that phages are highly specific for their host bacterium, there is no clear consensus on whether or not phage infection (and thus phage therapy) would impose collateral damage to non-target bacteria in polymicrobial communities. Here we provide direct evidence of how phage infection of a clinically relevant pathogen triggers an intrinsic type VII secretion system (T7SS) antibacterial response that consequently restricts the growth of neighboring bacterial cells that are not susceptible to phage infection. Phage induction of T7SS activity is a stress response and in addition to phages, T7SS antagonism can be induced using sub-inhibitory concentrations of antibiotics that facilitate membrane or DNA damage. Together these data show that a bacterial pathogen responds to diverse stressors to induce T7SS activity which manifests through the antagonism of neighboring non-kin bystander bacterial cells.
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Affiliation(s)
- Anushila Chatterjee
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States of America
| | - Julia L. E. Willett
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Gary M. Dunny
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, United States of America
| | - Breck A. Duerkop
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States of America
- * E-mail:
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11
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Affiliation(s)
- Felicity Alcock
- Microbes in Health and Disease Theme, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Tracy Palmer
- Microbes in Health and Disease Theme, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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12
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Are antibacterial effects of non-antibiotic drugs random or purposeful because of a common evolutionary origin of bacterial and mammalian targets? Infection 2020; 49:569-589. [PMID: 33325009 PMCID: PMC7737717 DOI: 10.1007/s15010-020-01547-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/28/2020] [Indexed: 01/09/2023]
Abstract
Purpose Advances in structural biology, genetics, bioinformatics, etc. resulted in the availability of an enormous pool of information enabling the analysis of the ancestry of pro- and eukaryotic genes and proteins. Methods This review summarizes findings of structural and/or functional homologies of pro- and eukaryotic enzymes catalysing analogous biological reactions because of their highly conserved active centres so that non-antibiotics interacted with bacterial targets. Results Protease inhibitors such as staurosporine or camostat inhibited bacterial serine/threonine or serine/tyrosine protein kinases, serine/threonine phosphatases, and serine/threonine kinases, to which penicillin-binding-proteins are linked, so that these drugs synergized with β-lactams, reverted aminoglycoside-resistance and attenuated bacterial virulence. Calcium antagonists such as nitrendipine or verapamil blocked not only prokaryotic ion channels but interacted with negatively charged bacterial cell membranes thus disrupting membrane energetics and inducing membrane stress response resulting in inhibition of P-glycoprotein such as bacterial pumps thus improving anti-mycobacterial activities of rifampicin, tetracycline, fluoroquinolones, bedaquilin and imipenem-activity against Acinetobacter spp. Ciclosporine and tacrolimus attenuated bacterial virulence. ACE-inhibitors like captopril interacted with metallo-β-lactamases thus reverting carbapenem-resistance; prokaryotic carbonic anhydrases were inhibited as well resulting in growth impairment. In general, non-antibiotics exerted weak antibacterial activities on their own but synergized with antibiotics, and/or reverted resistance and/or attenuated virulence. Conclusions Data summarized in this review support the theory that prokaryotic proteins represent targets for non-antibiotics because of a common evolutionary origin of bacterial- and mammalian targets resulting in highly conserved active centres of both, pro- and eukaryotic proteins with which the non-antibiotics interact and exert antibacterial actions.
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13
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Djorić D, Minton NE, Kristich CJ. The enterococcal PASTA kinase: A sentinel for cell envelope stress. Mol Oral Microbiol 2020; 36:132-144. [PMID: 32945615 DOI: 10.1111/omi.12313] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 09/05/2020] [Accepted: 09/08/2020] [Indexed: 12/12/2022]
Abstract
Enterococci are Gram-positive, opportunistic pathogens that reside throughout the gastrointestinal tracts of most terrestrial organisms. Enterococci are resistant to many antibiotics, which makes enterococcal infections difficult to treat. Enterococci are also particularly hardy bacteria that can tolerate a variety of environmental stressors. Understanding how enterococci sense and respond to the extracellular environment to enact adaptive biological responses may identify new targets that can be exploited for development of treatments for enterococcal infections. Bacterial eukaryotic-like serine/threonine kinases (eSTKs) and cognate phosphatases (STPs) are important signaling systems that mediate biological responses to extracellular stimuli. Some bacterial eSTKs are transmembrane proteins that contain a series of extracellular repeats of the penicillin-binding and Ser/Thr kinase-associated (PASTA) domain, leading to their designation as "PASTA kinases." Enterococcal genomes encode a single PASTA kinase and its cognate phosphatase. Investigations of the enterococcal PASTA kinase revealed its importance in resistance to antibiotics and other cell wall stresses, in enterococcal colonization of the mammalian gut, clues about its mechanism of signal transduction, and its integration with other enterococcal signal transduction systems. In this review, we describe the current state of knowledge of PASTA kinase signaling in enterococci and describe important gaps that still need to be addressed to provide a better understanding of this important signaling system.
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Affiliation(s)
- Dušanka Djorić
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Nicole E Minton
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Christopher J Kristich
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI, USA
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Labbe BD, Hall CL, Kellogg SL, Chen Y, Koehn O, Pickrum AM, Mirza SP, Kristich CJ. Reciprocal Regulation of PASTA Kinase Signaling by Differential Modification. J Bacteriol 2019; 201:e00016-19. [PMID: 30858297 PMCID: PMC6482931 DOI: 10.1128/jb.00016-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/01/2019] [Indexed: 12/20/2022] Open
Abstract
Transmembrane Ser/Thr kinases containing extracellular PASTA (penicillin-binding protein [PBP] and Ser/Thr-associated) domains are ubiquitous among Actinobacteria and Firmicutes species. Such PASTA kinases regulate critical bacterial processes, including antibiotic resistance, cell division, cell envelope homeostasis, and virulence, and are sometimes essential for viability. Previous studies of purified PASTA kinase fragments revealed they are capable of autophosphorylation in vitro, typically at multiple sites on the kinase domain. Autophosphorylation of a specific structural element of the kinase known as the activation loop is thought to enhance kinase activity in response to stimuli. However, the role of kinase phosphorylation at other sites is largely unknown. Moreover, the mechanisms by which PASTA kinases are deactivated once their stimulus has diminished are poorly understood. Enterococcus faecalis is a Gram-positive intestinal bacterium and a major antibiotic-resistant opportunistic pathogen. In E. faecalis, the PASTA kinase IreK drives intrinsic resistance to cell wall-active antimicrobials, and such antimicrobials trigger enhanced phosphorylation of IreK in vivo Here we identify multiple sites of phosphorylation on IreK and evaluate their function in vivo and in vitro While phosphorylation of the IreK activation loop is required for kinase activity, we found that phosphorylation at a site distinct from the activation loop reciprocally modulates IreK activity in vivo, leading to diminished activity (and diminished antimicrobial resistance). Moreover, this site is important for deactivation of IreK in vivo upon removal of an activating stimulus. Our results are consistent with a model in which phosphorylation of IreK at distinct sites reciprocally regulates IreK activity in vivo to promote adaptation to cell wall stresses.IMPORTANCE Transmembrane Ser/Thr kinases containing extracellular PASTA domains are ubiquitous among Actinobacteria and Firmicutes species and regulate critical processes, including antibiotic resistance, cell division, and cell envelope homeostasis. Previous studies of PASTA kinase fragments revealed autophosphorylation at multiple sites. However, the functional role of autophosphorylation and the relative impacts of phosphorylation at distinct sites are poorly understood. The PASTA kinase of Enterococcus faecalis, IreK, regulates intrinsic resistance to antimicrobials. Here we identify multiple sites of phosphorylation on IreK and show that modification of IreK at distinct sites reciprocally regulates IreK activity and antimicrobial resistance in vivo Thus, these results provide new insights into the mechanisms by which PASTA kinases can regulate critical physiological processes in a wide variety of bacterial species.
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Affiliation(s)
- Benjamin D Labbe
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Cherisse L Hall
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Stephanie L Kellogg
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Yao Chen
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Olivia Koehn
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Adam M Pickrum
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Shama P Mirza
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Christopher J Kristich
- Department of Microbiology and Immunology, Center for Infectious Disease Research, Medical College of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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Abstract
The study of the genetics of enterococci has focused heavily on mobile genetic elements present in these organisms, the complex regulatory circuits used to control their mobility, and the antibiotic resistance genes they frequently carry. Recently, more focus has been placed on the regulation of genes involved in the virulence of the opportunistic pathogenic species Enterococcus faecalis and Enterococcus faecium. Little information is available concerning fundamental aspects of DNA replication, partition, and division; this article begins with a brief overview of what little is known about these issues, primarily by comparison with better-studied model organisms. A variety of transcriptional and posttranscriptional mechanisms of regulation of gene expression are then discussed, including a section on the genetics and regulation of vancomycin resistance in enterococci. The article then provides extensive coverage of the pheromone-responsive conjugation plasmids, including sections on regulation of the pheromone response, the conjugative apparatus, and replication and stable inheritance. The article then focuses on conjugative transposons, now referred to as integrated, conjugative elements, or ICEs, and concludes with several smaller sections covering emerging areas of interest concerning the enterococcal mobilome, including nonpheromone plasmids of particular interest, toxin-antitoxin systems, pathogenicity islands, bacteriophages, and genome defense.
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The serine/threonine kinase Stk and the phosphatase Stp regulate cell wall synthesis in Staphylococcus aureus. Sci Rep 2018; 8:13693. [PMID: 30209409 PMCID: PMC6135852 DOI: 10.1038/s41598-018-32109-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/07/2018] [Indexed: 11/10/2022] Open
Abstract
The cell wall synthesis pathway producing peptidoglycan is a highly coordinated and tightly regulated process. Although the major components of bacterial cell walls have been known for decades, the complex regulatory network controlling peptidoglycan synthesis and many details of the cell division machinery are not well understood. The eukaryotic-like serine/threonine kinase Stk and the cognate phosphatase Stp play an important role in cell wall biosynthesis and drug resistance in S. aureus. We show that stp deletion has a pronounced impact on cell wall synthesis. Deletion of stp leads to a thicker cell wall and decreases susceptibility to lysostaphin. Stationary phase Δstp cells accumulate peptidoglycan precursors and incorporate higher amounts of incomplete muropeptides with non-glycine, monoglycine and monoalanine interpeptide bridges into the cell wall. In line with this cell wall phenotype, we demonstrate that the lipid II:glycine glycyltransferase FemX can be phosphorylated by the Ser/Thr kinase Stk in vitro. Mass spectrometric analyses identify Thr32, Thr36 and Ser415 as phosphoacceptors. The cognate phosphatase Stp dephosphorylates these phosphorylation sites. Moreover, Stk interacts with FemA and FemB, but is unable to phosphorylate them. Our data indicate that Stk and Stp modulate cell wall synthesis and cell division at several levels.
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Convergence of PASTA Kinase and Two-Component Signaling in Response to Cell Wall Stress in Enterococcus faecalis. J Bacteriol 2018; 200:JB.00086-18. [PMID: 29632091 DOI: 10.1128/jb.00086-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/03/2018] [Indexed: 12/20/2022] Open
Abstract
Two common signal transduction mechanisms used by bacteria to sense and respond to changing environments are two-component systems (TCSs) and eukaryote-like Ser/Thr kinases and phosphatases (eSTK/Ps). Enterococcus faecalis is a Gram-positive bacterium and a serious opportunistic pathogen that relies on both a TCS and an eSTK/P pathway for intrinsic resistance to cell wall-targeting antibiotics. The TCS consists of a histidine kinase (CroS) and a response regulator (CroR) that become activated upon exposure of cells to cell wall-targeting antibiotics, leading to a modulation of gene expression. The eSTK/P pathway consists of a transmembrane kinase (IreK) and its cognate phosphatase (IreP), which act antagonistically to mediate antibiotic resistance through an unknown mechanism. Because both CroS/R and IreK/P contribute to enterococcal resistance toward cell wall-targeting antibiotics, we hypothesized that these signaling systems are intertwined. To test this hypothesis, we analyzed CroR phosphorylation and CroS/R-dependent gene expression to probe the influence of IreK and IreP on CroS/R signaling. In addition, we analyzed the phosphorylation state of CroS, which revealed the IreK-dependent phosphorylation of a Thr residue important for CroS function. Our results are consistent with a model in which IreK positively influences CroR-dependent gene expression through the phosphorylation of CroS to promote antimicrobial resistance in E. faecalis IMPORTANCE Two-component signaling systems (TCSs) and eukaryote-like Ser/Thr kinases (eSTKs) are used by bacteria to sense and adapt to changing environments. Understanding how these pathways are regulated to promote bacterial survival is critical for a more complete understanding of bacterial stress responses and physiology. The opportunistic pathogen Enterococcus faecalis relies on both a TCS (CroS/R) and an eSTK (IreK) for intrinsic resistance to cell wall-targeting antibiotics. We probed the relationship between CroS/R and IreK, revealing the convergence of IreK and the sensor kinase CroS to enhance signaling through CroS/R and increase antimicrobial resistance in E. faecalis This newly described example of eSTK/TCS convergence adds to our understanding of the signaling networks mediating antimicrobial resistance in E. faecalis.
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Pompeo F, Byrne D, Mengin-Lecreulx D, Galinier A. Dual regulation of activity and intracellular localization of the PASTA kinase PrkC during Bacillus subtilis growth. Sci Rep 2018; 8:1660. [PMID: 29374241 PMCID: PMC5786024 DOI: 10.1038/s41598-018-20145-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/15/2018] [Indexed: 12/13/2022] Open
Abstract
The activity of the PrkC protein kinase is regulated in a sophisticated manner in Bacillus subtilis cells. In spores, in the presence of muropeptides, PrkC stimulates dormancy exit. The extracellular region containing PASTA domains binds peptidoglycan fragments to probably enhance the intracellular kinase activity. During exponential growth, the cell division protein GpsB interacts with the intracellular domain of PrkC to stimulate its activity. In this paper, we have reinvestigated the regulation of PrkC during exponential and stationary phases. We observed that, during exponential growth, neither its septal localization nor its activity are influenced by the addition of peptidoglycan fragments or by the deletion of one or all PASTA domains. However, Dynamic Light Scattering experiments suggest that peptidoglycan fragments bind specifically to PrkC and induce its oligomerization. In addition, during stationary phase, PrkC appeared evenly distributed in the cell wall and the deletion of one or all PASTA domains led to a non-activated kinase. We conclude that PrkC activation is not as straightforward as previously suggested and that regulation of its kinase activity via the PASTA domains and peptidoglycan fragments binding occurs when PrkC is not concentrated to the bacterial septum, but all over the cell wall in non-dividing bacillus cells.
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Affiliation(s)
- Frédérique Pompeo
- Laboratoire de Chimie Bactérienne, UMR 7283, IMM, CNRS, Aix Marseille Univ, 31 Chemin Joseph Aiguier, 13009, Marseille, France.
| | - Deborah Byrne
- Protein Expression Facility, IMM, CNRS, Aix Marseille Univ, 31 Chemin Joseph Aiguier, 13009, Marseille, France
| | - Dominique Mengin-Lecreulx
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud and Université Paris-Saclay, 91198, Gif-sur-Yvette, France
| | - Anne Galinier
- Laboratoire de Chimie Bactérienne, UMR 7283, IMM, CNRS, Aix Marseille Univ, 31 Chemin Joseph Aiguier, 13009, Marseille, France
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Modulators of Enterococcus faecalis Cell Envelope Integrity and Antimicrobial Resistance Influence Stable Colonization of the Mammalian Gastrointestinal Tract. Infect Immun 2017; 86:IAI.00381-17. [PMID: 29038125 DOI: 10.1128/iai.00381-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/09/2017] [Indexed: 02/07/2023] Open
Abstract
The Gram-positive bacterium Enterococcus faecalis is both a colonizer of the gastrointestinal tract (GIT) and an agent of serious nosocomial infections. Although it is typically required for pathogenesis, GIT colonization by E. faecalis is poorly understood. E. faecalis tolerates high concentrations of GIT antimicrobials, like cholate and lysozyme, leading us to hypothesize that resistance to intestinal antimicrobials is essential for long-term GIT colonization. Analyses of E. faecalis mutants exhibiting defects in antimicrobial resistance revealed that IreK, a determinant of envelope integrity and antimicrobial resistance, is required for long-term GIT colonization. IreK is a member of the PASTA kinase protein family, bacterial transmembrane signaling proteins implicated in the regulation of cell wall homeostasis. Among several determinants of cholate and lysozyme resistance in E. faecalis, IreK was the only one found to be required for intestinal colonization, emphasizing the importance of this protein to enterococcal adaptation to the GIT. By studying ΔireK suppressor mutants that recovered the ability to colonize the GIT, we identified two conserved enterococcal proteins (OG1RF_11271 and OG1RF_11272) that function antagonistically to IreK and interfere with cell envelope integrity, antimicrobial resistance, and GIT colonization. Our data suggest that IreK, through its kinase activity, inhibits the actions of these proteins. IreK, OG1RF_11271, and OG1RF_11272 are found in all enterococci, suggesting that their effect on GIT colonization is universal across enterococci. Thus, we have defined conserved genes in the enterococcal core genome that influence GIT colonization through their effect on enterococcal envelope integrity and antimicrobial resistance.
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