1
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Oliva RL, Vogt C, Bublitz TA, Camenzind T, Dyckmans J, Joergensen RG. Galactosamine and mannosamine are integral parts of bacterial and fungal extracellular polymeric substances. ISME COMMUNICATIONS 2024; 4:ycae038. [PMID: 38616925 PMCID: PMC11014887 DOI: 10.1093/ismeco/ycae038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/19/2023] [Accepted: 03/18/2024] [Indexed: 04/16/2024]
Abstract
Extracellular polymeric substances (EPS) are produced by microorganisms and interact to form a complex matrix called biofilm. In soils, EPS are important contributors to the microbial necromass and, thus, to soil organic carbon (SOC). Amino sugars (AS) are used as indicators for microbial necromass in soil, although the origin of galactosamine and mannosamine is largely unknown. However, indications exist that they are part of EPS. In this study, two bacteria and two fungi were grown in starch medium either with or without a quartz matrix to induce EPS production. Each culture was separated in two fractions: one that directly underwent AS extraction (containing AS from both biomass and EPS), and another that first had EPS extracted, followed then by AS determination (exclusively containing AS from EPS). We did not observe a general effect of the quartz matrix neither of microbial type on AS production. The quantified amounts of galactosamine and mannosamine in the EPS fraction represented on average 100% of the total amounts of these two AS quantified in cell cultures, revealing they are integral parts of the biofilm. In contrast, muramic acid and glucosamine were also quantified in the EPS, but with much lower contribution rates to total AS production, of 18% and 33%, respectively, indicating they are not necessarily part of EPS. Our results allow a meaningful ecological interpretation of mannosamine and galactosamine data in the future as indicators of microbial EPS, and also attract interest of future studies to investigate the role of EPS to SOC and its dynamics.
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Affiliation(s)
- Rebeca Leme Oliva
- Soil Biology and Plant Nutrition, University of Kassel, 37213 Witzenhausen, Germany
| | - Carla Vogt
- Soil Biology and Plant Nutrition, University of Kassel, 37213 Witzenhausen, Germany
| | - Tábata Aline Bublitz
- Soil Biology and Plant Nutrition, University of Kassel, 37213 Witzenhausen, Germany
| | - Tessa Camenzind
- Institute of Biology, Department of Plant Ecology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Jens Dyckmans
- Centre for Stable Isotope Research Analysis, University of Göttingen, 37077 Göttingen, Germany
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2
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Nakamoto R, Bamyaci S, Blomqvist K, Normark S, Henriques-Normark B, Sham LT. The divisome but not the elongasome organizes capsule synthesis in Streptococcus pneumoniae. Nat Commun 2023; 14:3170. [PMID: 37264013 DOI: 10.1038/s41467-023-38904-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 05/16/2023] [Indexed: 06/03/2023] Open
Abstract
The bacterial cell envelope consists of multiple layers, including the peptidoglycan cell wall, one or two membranes, and often an external layer composed of capsular polysaccharides (CPS) or other components. How the synthesis of all these layers is precisely coordinated remains unclear. Here, we identify a mechanism that coordinates the synthesis of CPS and peptidoglycan in Streptococcus pneumoniae. We show that CPS synthesis initiates from the division septum and propagates along the long axis of the cell, organized by the tyrosine kinase system CpsCD. CpsC and the rest of the CPS synthesis complex are recruited to the septum by proteins associated with the divisome (a complex involved in septal peptidoglycan synthesis) but not the elongasome (involved in peripheral peptidoglycan synthesis). Assembly of the CPS complex starts with CpsCD, then CpsA and CpsH, the glycosyltransferases, and finally CpsJ. Remarkably, targeting CpsC to the cell pole is sufficient to reposition CPS synthesis, leading to diplococci that lack CPS at the septum. We propose that septal CPS synthesis is important for chain formation and complement evasion, thereby promoting bacterial survival inside the host.
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Affiliation(s)
- Rei Nakamoto
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
| | - Sarp Bamyaci
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, SE-17177, Sweden
| | - Karin Blomqvist
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, SE-17177, Sweden
- Clinical Microbiology, Karolinska University Hospital Solna, SE-17176, Stockholm, Sweden
| | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, SE-17177, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, SE-17177, Sweden
- Clinical Microbiology, Karolinska University Hospital Solna, SE-17176, Stockholm, Sweden
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore.
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3
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Rigolot V, Rossez Y, Biot C, Lion C. A bioorthogonal chemistry approach to detect the K1 polysialic acid capsule in Escherichia coli. RSC Chem Biol 2023; 4:173-183. [PMID: 36794016 PMCID: PMC9906323 DOI: 10.1039/d2cb00219a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022] Open
Abstract
Most Escherichia coli strains associated with neonatal meningitis express the K1 capsule, a sialic acid polysaccharide that is directly related to their pathogenicity. Metabolic oligosaccharide engineering (MOE) has mostly been developed in eukaryotes, but has also been successfully applied to the study of several oligosaccharides or polysaccharides constitutive of the bacterial cell wall. However, bacterial capsules are seldom targeted despite their important role as virulence factors, and the K1 polysialic acid (PSA) antigen that shields bacteria from the immune system still remains untackled. Herein, we report a fluorescence microplate assay that allows the fast and facile detection of K1 capsules with an approach that combines MOE and bioorthogonal chemistry. We exploit the incorporation of synthetic analogues of N-acetylmannosamine or N-acetylneuraminic acid, metabolic precursors of PSA, and copper-catalysed azide-alkyne cycloaddition (CuAAC) as the click chemistry reaction to specifically label the modified K1 antigen with a fluorophore. The method was optimized, validated by capsule purification and fluorescence microscopy, and applied to the detection of whole encapsulated bacteria in a miniaturized assay. We observe that analogues of ManNAc are readily incorporated into the capsule while those of Neu5Ac are less efficiently metabolized, which provides useful information regarding the capsule biosynthetic pathways and the promiscuity of the enzymes involved. Moreover, this microplate assay is transferable to screening approaches and may provide a platform to identify novel capsule-targeted antibiotics that would circumvent resistance issues.
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Affiliation(s)
- Vincent Rigolot
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle Lille France
| | - Yannick Rossez
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle Lille France
| | - Christophe Biot
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle Lille France
| | - Cédric Lion
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle Lille France
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4
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Li M, Yu J, Cao L, Yin Y, Su Z, Chen S, Li G, Ma T. Facultative anaerobic conversion of lignocellulose biomass to new bioemulsifier by thermophilic Geobacillus thermodenitrificans NG80-2. JOURNAL OF HAZARDOUS MATERIALS 2023; 443:130210. [PMID: 36308930 DOI: 10.1016/j.jhazmat.2022.130210] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 10/06/2022] [Accepted: 10/16/2022] [Indexed: 06/16/2023]
Abstract
Heavy oil has hindered crude oil exploitation and pollution remediation due to its high density and viscosity. Bioemulsifiers efficiently facilitate the formation and stabilization of oil-in-water emulsions in low concentrations thus eliminating the above bottleneck. Despite their potential benefits, various obstacles had still impeded the practical applications of bioemulsifiers, including high purification costs and poor adaptability to extreme environments such as high temperature and oxygen deficiency. Herein, thermophilic facultative anaerobic Geobacillus thermodenitrificans NG80-2 was proved capable of emulsifying heavy oils and reducing their viscosity. An exocelluar bioemulsifier could be produced by NG80-2 using low-cost lignocellulose components as carbon sources even under anaerobic condition. The purified bioemulsifier was proved to be polysaccharide-protein complexes, and both components contributed to its emulsifying capability. In addition, it displayed excellent stress tolerance over wide ranges of temperatures, salinities, and pHs. Meanwhile, the bioemulsifier significantly improved oil recovery and degradation efficiency. An eps gene cluster for polysaccharide biosynthesis and genes for the covalently bonded proteins was further certificated. Therefore, the bioemulsifier produced by G. thermodenitrificans NG80-2 has immense potential for applications in bioremediation and EOR, and its biosynthesis pathway revealed here provides a theoretical basis for increasing bioemulsifier output.
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Affiliation(s)
- Mingchang Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jiaqi Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Lu Cao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yujun Yin
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhaoying Su
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Shuai Chen
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Guoqiang Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; Tianjin Engineering Technology Center of Green Manufacturing Biobased Materials, Tianjin 300071, China
| | - Ting Ma
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; Tianjin Engineering Technology Center of Green Manufacturing Biobased Materials, Tianjin 300071, China.
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5
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Encapsulation of the septal cell wall protects Streptococcus pneumoniae from its major peptidoglycan hydrolase and host defenses. PLoS Pathog 2022; 18:e1010516. [PMID: 35731836 PMCID: PMC9216600 DOI: 10.1371/journal.ppat.1010516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 04/11/2022] [Indexed: 11/19/2022] Open
Abstract
Synthesis of the capsular polysaccharide, a major virulence factor for many pathogenic bacteria, is required for bacterial survival within the infected host. In Streptococcus pneumoniae, Wze, an autophosphorylating tyrosine kinase, and Wzd, a membrane protein required for Wze autophosphorylation, co-localize at the division septum and guarantee the presence of capsule at this subcellular location. To determine how bacteria regulate capsule synthesis, we studied pneumococcal proteins that interact with Wzd and Wze using bacterial two hybrid assays and fluorescence microscopy. We found that Wzd interacts with Wzg, the putative ligase that attaches capsule to the bacterial cell wall, and recruits it to the septal area. This interaction required residue V56 of Wzd and both the transmembrane regions and DNA-PPF domain of Wzg. When compared to the wild type, Wzd null pneumococci lack capsule at midcell, bind the peptidoglycan hydrolase LytA better and are more susceptible to LytA-induced lysis, and are less virulent in a zebrafish embryo infection model. In this manuscript, we propose that the Wzd/Wze pair guarantees full encapsulation of pneumococcal bacteria by recruiting Wzg to the division septum, ensuring that capsule attachment is coordinated with peptidoglycan synthesis. Impairing the encapsulation process, at localized subcellular sites, may facilitate elimination of bacteria by strategies that target the pneumococcal peptidoglycan.
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6
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The bacterial tyrosine kinase system CpsBCD governs the length of capsule polymers. Proc Natl Acad Sci U S A 2021; 118:2103377118. [PMID: 34732571 DOI: 10.1073/pnas.2103377118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2021] [Indexed: 12/17/2022] Open
Abstract
Many pathogenic bacteria are encased in a layer of capsular polysaccharide (CPS). This layer is important for virulence by masking surface antigens, preventing opsonophagocytosis, and avoiding mucus entrapment. The bacterial tyrosine kinase (BY-kinase) regulates capsule synthesis and helps bacterial pathogens to survive different host niches. BY-kinases autophosphorylate at the C-terminal tyrosine residues upon external stimuli, but the role of phosphorylation is still unclear. Here, we report that the BY-kinase CpsCD is required for growth in Streptococcus pneumoniae Cells lacking a functional cpsC or cpsD accumulated low molecular weight CPS and lysed because of the lethal sequestration of the lipid carrier undecaprenyl phosphate, resulting in inhibition of peptidoglycan (PG) synthesis. CpsC interacts with CpsD and the polymerase CpsH. CpsD phosphorylation reduces the length of CPS polymers presumably by controlling the activity of CpsC. Finally, pulse-chase experiments reveal the spatiotemporal coordination between CPS and PG synthesis. This coordination is dependent on CpsC and CpsD. Together, our study provides evidence that BY-kinases regulate capsule polymer length by fine-tuning CpsC activity through autophosphorylation.
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7
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Cellular Mn/Zn Ratio Influences Phosphoglucomutase Activity and Capsule Production in Streptococcus pneumoniae D39. J Bacteriol 2021; 203:e0060220. [PMID: 33875543 PMCID: PMC8316032 DOI: 10.1128/jb.00602-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Capsular polysaccharide (CPS) is a major virulence determinant for many human-pathogenic bacteria. Although the essential functional roles for CPS in bacterial virulence have been established, knowledge of how CPS production is regulated remains limited. Streptococcus pneumoniae (pneumococcus) CPS expression levels and overall thickness change in response to available oxygen and carbohydrate. These nutrients in addition to transition metal ions can vary significantly between host environmental niches and infection stage. Since the pneumococcus must modulate CPS expression among various host niches during disease progression, we examined the impact of the nutritional transition metal availability of manganese (Mn) and zinc (Zn) on CPS production. We demonstrate that increased Mn/Zn ratios increase CPS production via Mn-dependent activation of the phosphoglucomutase Pgm, an enzyme that functions at the branch point between glycolysis and the CPS biosynthetic pathway in a transcription-independent manner. Furthermore, we find that the downstream CPS protein CpsB, an Mn-dependent phosphatase, does not promote aberrant dephosphorylation of its target capsule-tyrosine kinase CpsD during Mn stress. Together, these data reveal a direct role for cellular Mn/Zn ratios in the regulation of CPS biosynthesis via the direct activation of Pgm. We propose a multilayer mechanism used by the pneumococcus in regulating CPS levels across various host niches. IMPORTANCE Evolving evidence strongly indicates that maintenance of metal homeostasis is essential for establishing colonization and continued growth of bacterial pathogens in the vertebrate host. In this study, we demonstrate the impact of cellular manganese/zinc (Mn/Zn) ratios on bacterial capsular polysaccharide (CPS) production, an important virulence determinant of many human-pathogenic bacteria, including Streptococcus pneumoniae. We show that higher Mn/Zn ratios increase CPS production via the Mn-dependent activation of the phosphoglucomutase Pgm, an enzyme that functions at the branch point between glycolysis and the CPS biosynthetic pathway. The findings provide a direct role for Mn/Zn homeostasis in the regulation of CPS expression levels and further support the ability of metal cations to act as important cellular signaling mediators in bacteria.
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8
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Su T, Nakamoto R, Chun YY, Chua WZ, Chen JH, Zik JJ, Sham LT. Decoding capsule synthesis in Streptococcus pneumoniae. FEMS Microbiol Rev 2020; 45:6041728. [PMID: 33338218 DOI: 10.1093/femsre/fuaa067] [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: 06/10/2020] [Accepted: 12/07/2020] [Indexed: 12/20/2022] Open
Abstract
Streptococcus pneumoniae synthesizes more than one hundred types of capsular polysaccharides (CPS). While the diversity of the enzymes and transporters involved is enormous, it is not limitless. In this review, we summarized the recent progress on elucidating the structure-function relationships of CPS, the mechanisms by which they are synthesized, how their synthesis is regulated, the host immune response against them, and the development of novel pneumococcal vaccines. Based on the genetic and structural information available, we generated provisional models of the CPS repeating units that remain unsolved. In addition, to facilitate cross-species comparisons and assignment of glycosyltransferases, we illustrated the biosynthetic pathways of the known CPS in a standardized format. Studying the intricate steps of pneumococcal CPS assembly promises to provide novel insights for drug and vaccine development as well as improve our understanding of related pathways in other species.
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Affiliation(s)
- Tong Su
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Rei Nakamoto
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Ye Yu Chun
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Wan Zhen Chua
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Jia Hui Chen
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Justin J Zik
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
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Pelletier A, Freton C, Gallay C, Trouve J, Cluzel C, Franz-Wachtel M, Macek B, Jault JM, Grangeasse C, Guiral S. The Tyrosine-Autokinase UbK Is Required for Proper Cell Growth and Cell Morphology of Streptococcus pneumoniae. Front Microbiol 2019; 10:1942. [PMID: 31551943 PMCID: PMC6733980 DOI: 10.3389/fmicb.2019.01942] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/07/2019] [Indexed: 12/11/2022] Open
Abstract
Protein phosphorylation is a key post-translational modification required for many cellular functions of the bacterial cell. Recently, we identified a new protein-kinase, named UbK, in Bacillus subtilis that belongs to a new family of protein-kinases widespread in bacteria. In this study, we analyze the function of UbK in Streptococcus pneumoniae. We show that UbK displays a tyrosine-kinase activity and autophosphorylates on a unique tyrosine in vivo. To get insights into its cellular role, we constructed a set of pneumococcal ubk mutants. Using conventional and electron microscopy, we show that the ubk deficient strain, as well as an ubk catalytic dead mutant, display both severe cell-growth and cell-morphology defects. The same defects are observed with a mutant mimicking permanent phosphorylation of UbK whereas they are not detected for a mutant mimicking defective autophosphorylation of UbK. Moreover, we find that UbK phosphorylation promotes its ability to hydrolyze ATP. These observations show that the hydrolysis of ATP by UbK serves not only for its autophosphorylation but also for a distinct purpose essential for the optimal cell growth and cell-morphogenesis of the pneumococcus. We thus propose a model in which the autophosphorylation/dephosphorylation of UbK regulates its cellular function through a negative feedback loop.
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Affiliation(s)
- Anaïs Pelletier
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS/Université Lyon 1, Lyon, France
| | - Céline Freton
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS/Université Lyon 1, Lyon, France
| | - Clément Gallay
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS/Université Lyon 1, Lyon, France
| | - Jennyfer Trouve
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS/Université Lyon 1, Lyon, France
| | - Caroline Cluzel
- Laboratoire de Biologie Tissulaire et d'Ingénierie Thérapeutique, UMR 5305 CNRS/Université Lyon 1, Lyon, France
| | | | - Boris Macek
- Proteome Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Jean-Michel Jault
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS/Université Lyon 1, Lyon, France
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS/Université Lyon 1, Lyon, France
| | - Sébastien Guiral
- Molecular Microbiology and Structural Biochemistry, UMR 5086 CNRS/Université Lyon 1, Lyon, France
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10
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Mercy C, Ducret A, Slager J, Lavergne JP, Freton C, Nagarajan SN, Garcia PS, Noirot-Gros MF, Dubarry N, Nourikyan J, Veening JW, Grangeasse C. RocS drives chromosome segregation and nucleoid protection in Streptococcus pneumoniae. Nat Microbiol 2019; 4:1661-1670. [PMID: 31182798 DOI: 10.1038/s41564-019-0472-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 04/26/2019] [Indexed: 11/09/2022]
Abstract
Chromosome segregation in bacteria is poorly understood outside some prominent model strains1-5 and even less is known about how it is coordinated with other cellular processes. This is the case for the opportunistic human pathogen Streptococcus pneumoniae (the pneumococcus)6, which lacks the Min and the nucleoid occlusion systems7, and possesses only an incomplete chromosome partitioning Par(A)BS system, in which ParA is absent8. The bacterial tyrosine kinase9 CpsD, which is required for capsule production, was previously found to interfere with chromosome segregation10. Here, we identify a protein of unknown function that interacts with CpsD and drives chromosome segregation. RocS (Regulator of Chromosome Segregation) is a membrane-bound protein that interacts with both DNA and the chromosome partitioning protein ParB to properly segregate the origin of replication region to new daughter cells. In addition, we show that RocS interacts with the cell division protein FtsZ and hinders cell division. Altogether, this work reveals that RocS is the cornerstone of a nucleoid protection system ensuring proper chromosome segregation and cell division in coordination with the biogenesis of the protective capsular layer.
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Affiliation(s)
- Chryslène Mercy
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Lyon, France
| | - Adrien Ducret
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Lyon, France
| | - Jelle Slager
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands
| | - Jean-Pierre Lavergne
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Lyon, France
| | - Céline Freton
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Lyon, France
| | - Sathya Narayanan Nagarajan
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Lyon, France
| | - Pierre Simon Garcia
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Lyon, France
| | - Marie-Francoise Noirot-Gros
- Micalis Institute, UMR1319, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.,Biosciences Division, Argonne National Laboratory, Lemont, IL, USA
| | - Nelly Dubarry
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Lyon, France.,Evotec ID, Marcy l'Etoile, France
| | - Julien Nourikyan
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Lyon, France
| | - Jan-Willem Veening
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, The Netherlands.,Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne, Switzerland
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry, UMR 5086, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique, Lyon, France.
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11
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Abstract
The polysaccharide capsule of Streptococcus pneumoniae is the dominant surface structure of the organism and plays a critical role in virulence, principally by interfering with host opsonophagocytic clearance mechanisms. The capsule is the target of current pneumococcal vaccines, but there are 98 currently recognised polysaccharide serotypes and protection is strictly serotype-specific. Widespread use of these vaccines is driving changes in serotype prevalence in both carriage and disease. This chapter summarises current knowledge on the role of the capsule and its regulation in pathogenesis, the mechanisms of capsule synthesis, the genetic basis for serotype differences, and provides insights into how so many structurally distinct capsular serotypes have evolved. Such knowledge will inform ongoing refinement of pneumococcal vaccination strategies.
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12
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Phanphak S, Georgiades P, Li R, King J, Roberts IS, Waigh TA. Super-Resolution Fluorescence Microscopy Study of the Production of K1 Capsules by Escherichia coli: Evidence for the Differential Distribution of the Capsule at the Poles and the Equator of the Cell. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5635-5646. [PMID: 30916568 PMCID: PMC6492954 DOI: 10.1021/acs.langmuir.8b04122] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The production of Escherichia coli K1 serotype capsule was investigated using direct stochastic optical reconstruction microscopy with live bacteria and graphene oxide-coated coverslips, overcoming many morphological artifacts found in other high-resolution imaging techniques. Super-resolution fluorescence images showed that the K1 capsular polysaccharide is not uniformly distributed on the cell surface, as previously thought. These studies demonstrated that on the cell surfaces the K1 capsule at the poles had bimodal thicknesses of 238 ± 41 and 323 ± 62 nm, whereas at the equator, there was a monomodal thickness of 217 ± 29 nm. This bimodal variation was also observed in high-pressure light-scattering chromatography measurements of purified K1 capsular polysaccharide. Particle tracking demonstrated that the formation of the capsule was dominated by the expansion of lyso-phosphatidylglycerol (lyso-PG) rafts that anchor the capsular polysaccharide in the outer membrane, and the expansion of these rafts across the cell surface was driven by new material transported through the capsular biosynthesis channels. The discovery of thicker capsules at the poles of the cell will have implications in mediating interactions between the bacterium and its immediate environment.
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Affiliation(s)
| | | | | | - Jane King
- Faculty of Biology, Medicine and Health, Michael Smith Building , The University of Manchester , Dover Street , Manchester M13 9PL , U.K
| | - Ian S Roberts
- Faculty of Biology, Medicine and Health, Michael Smith Building , The University of Manchester , Dover Street , Manchester M13 9PL , U.K
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13
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Zeidan AA, Poulsen VK, Janzen T, Buldo P, Derkx PMF, Øregaard G, Neves AR. Polysaccharide production by lactic acid bacteria: from genes to industrial applications. FEMS Microbiol Rev 2017; 41:S168-S200. [DOI: 10.1093/femsre/fux017] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/29/2017] [Indexed: 01/14/2023] Open
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Grangeasse C. Rewiring the Pneumococcal Cell Cycle with Serine/Threonine- and Tyrosine-kinases. Trends Microbiol 2016; 24:713-724. [DOI: 10.1016/j.tim.2016.04.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 03/23/2016] [Accepted: 04/07/2016] [Indexed: 12/14/2022]
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15
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Mitra SD, Afonina I, Kline KA. Right Place, Right Time: Focalization of Membrane Proteins in Gram-Positive Bacteria. Trends Microbiol 2016; 24:611-621. [PMID: 27117048 DOI: 10.1016/j.tim.2016.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 03/03/2016] [Accepted: 03/24/2016] [Indexed: 11/25/2022]
Abstract
Membrane proteins represent a significant proportion of total bacterial proteins and perform vital cellular functions ranging from exchanging metabolites and genetic material, secretion and sorting, sensing signal molecules, and cell division. Many of these functions are carried out at distinct foci on the bacterial membrane, and this subcellular localization can be coordinated by a number of factors, including lipid microdomains, protein-protein interactions, and membrane curvature. Elucidating the mechanisms behind focal protein localization in bacteria informs not only protein structure-function correlation, but also how to disrupt the protein function to limit virulence. Here we review recent advances describing a functional role for subcellular localization of membrane proteins involved in genetic transfer, secretion and sorting, cell division and growth, and signaling.
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Affiliation(s)
- Sumitra D Mitra
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Irina Afonina
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore.
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16
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Abstract
Streptococcus pneumoniae (the pneumococcus) is an important human pathogen. Its virulence is largely due to its polysaccharide capsule, which shields it from the host immune system, and because of this, the capsule has been extensively studied. Studies of the capsule led to the identification of DNA as the genetic material, identification of many different capsular serotypes, and identification of the serotype-specific nature of protection by adaptive immunity. Recent studies have led to the determination of capsular polysaccharide structures for many serotypes using advanced analytical technologies, complete elucidation of genetic basis for the capsular types, and the development of highly effective pneumococcal conjugate vaccines. Conjugate vaccine use has altered the serotype distribution by either serotype replacement or switching, and this has increased the need to serotype pneumococci. Due to great advances in molecular technologies and our understanding of the pneumococcal genome, molecular approaches have become powerful tools to predict pneumococcal serotypes. In addition, more-precise and -efficient serotyping methods that directly detect polysaccharide structures are emerging. These improvements in our capabilities will greatly enhance future investigations of pneumococcal epidemiology and diseases and the biology of colonization and innate immunity to pneumococcal capsules.
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Nourikyan J, Kjos M, Mercy C, Cluzel C, Morlot C, Noirot-Gros MF, Guiral S, Lavergne JP, Veening JW, Grangeasse C. Autophosphorylation of the Bacterial Tyrosine-Kinase CpsD Connects Capsule Synthesis with the Cell Cycle in Streptococcus pneumoniae. PLoS Genet 2015; 11:e1005518. [PMID: 26378458 PMCID: PMC4574921 DOI: 10.1371/journal.pgen.1005518] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 08/21/2015] [Indexed: 01/07/2023] Open
Abstract
Bacterial capsular polysaccharides (CPS) are produced by a multi-protein membrane complex, in which a particular type of tyrosine-autokinases named BY-kinases, regulate their polymerization and export. However, our understanding of the role of BY-kinases in these processes remains incomplete. In the human pathogen Streptococcus pneumoniae, the BY-kinase CpsD localizes at the division site and participates in the proper assembly of the capsule. In this study, we show that the cytoplasmic C-terminal end of the transmembrane protein CpsC is required for CpsD autophosphorylation and localization at mid-cell. Importantly, we demonstrate that the CpsC/CpsD complex captures the polysaccharide polymerase CpsH at the division site. Together with the finding that capsule is not produced at the division site in cpsD and cpsC mutants, these data show that CPS production occurs exclusively at mid-cell and is tightly dependent on CpsD interaction with CpsC. Next, we have analyzed the impact of CpsD phosphorylation on CPS production. We show that dephosphorylation of CpsD induces defective capsule production at the septum together with aberrant cell elongation and nucleoid defects. We observe that the cell division protein FtsZ assembles and localizes properly although cell constriction is impaired. DAPI staining together with localization of the histone-like protein HlpA further show that chromosome replication and/or segregation is defective suggesting that CpsD autophosphorylation interferes with these processes thus resulting in cell constriction defects and cell elongation. We show that CpsD shares structural homology with ParA-like ATPases and that it interacts with the chromosome partitioning protein ParB. Total internal reflection fluorescence microscopy imaging demonstrates that CpsD phosphorylation modulates the mobility of ParB. These data support a model in which phosphorylation of CpsD acts as a signaling system coordinating CPS synthesis with chromosome segregation to ensure that daughter cells are properly wrapped in CPS. Bacteria utilize a multi-protein membrane complex to synthesize and export the polysaccharide capsule that conceals and covers the cell. In bacterial pathogens, the capsule protects the cell form opsonophagocytosis and complement-mediated killing. The mechanisms allowing the bacterial cell to maintain this protective capsule during cell growth and division remain unknown. The capsule assembly machinery encompasses a particular type of tyrosine-kinases found only in bacteria, which are called BY-kinases. These kinases are involved in the regulation of several cellular functions including polysaccharide capsule production. Studying the role of BY-kinase represents thus an interesting approach to decipher the mechanisms of capsule synthesis and export. Here, we study the role of the BY-kinase CpsD in the human pathogen Streptococcus pneumoniae. We show that CpsD plays a dual function in the pneumococcus. Indeed, CpsD captures the capsule assembly machinery at the site of division, but we also show that CpsD coordinates capsule production with the cell cycle by interacting with the chromosome segregation system. These features provide a simple mechanism to cover the complete surface of the pneumococcal daughter cells. This finding further opens a new view of the function of BY-kinases in the bacterial cell notably in localizing protein complexes in subcellular regions over the cell cycle.
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Affiliation(s)
- Julien Nourikyan
- Bases Moléculaires et Structurales des Systèmes Infectieux, UMR5086 CNRS/Université de Lyon 1, Lyon, France
| | - Morten Kjos
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, the Netherlands
| | - Chryslène Mercy
- Bases Moléculaires et Structurales des Systèmes Infectieux, UMR5086 CNRS/Université de Lyon 1, Lyon, France
| | - Caroline Cluzel
- Laboratoire Biologie Tissulaire et Ingénierie thérapeutique, UMR5305, CNRS/Université de Lyon 1, Lyon, France
| | - Cécile Morlot
- Institut de Biologie Structurale, UMR5075 CNRS/CEA/Université Grenoble Alpes, Grenoble, France
| | | | - Sébastien Guiral
- Bases Moléculaires et Structurales des Systèmes Infectieux, UMR5086 CNRS/Université de Lyon 1, Lyon, France
| | - Jean-Pierre Lavergne
- Bases Moléculaires et Structurales des Systèmes Infectieux, UMR5086 CNRS/Université de Lyon 1, Lyon, France
| | - Jan-Willem Veening
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Groningen, the Netherlands
| | - Christophe Grangeasse
- Bases Moléculaires et Structurales des Systèmes Infectieux, UMR5086 CNRS/Université de Lyon 1, Lyon, France
- * E-mail:
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18
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Derouiche A, Shi L, Bidnenko V, Ventroux M, Pigonneau N, Franz-Wachtel M, Kalantari A, Nessler S, Noirot-Gros MF, Mijakovic I. Bacillus subtilis SalA is a phosphorylation-dependent transcription regulator that represses scoC and activates the production of the exoprotease AprE. Mol Microbiol 2015; 97:1195-208. [PMID: 26094643 DOI: 10.1111/mmi.13098] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2015] [Indexed: 11/29/2022]
Abstract
Bacillus subtilis Mrp family protein SalA has been shown to indirectly promote the production of the exoprotease AprE by inhibiting the expression of scoC, which codes for a repressor of aprE. The exact mechanism by which SalA influences scoC expression has not been clarified previously. We demonstrate that SalA possesses a DNA-binding domain (residues 1-60), which binds to the promoter region of scoC. The binding of SalA to its target DNA depends on the presence of ATP and is stimulated by phosphorylation of SalA at tyrosine 327. The B. subtilis protein-tyrosine kinase PtkA interacts specifically with the C-terminal domain of SalA in vivo and in vitro and is responsible for activating its DNA binding via phosphorylation of tyrosine 327. In vivo, a mutant mimicking phosphorylation of SalA (SalA Y327E) exhibited a strong repression of scoC and consequently overproduction of AprE. By contrast, the non-phosphorylatable SalA Y327F and the ΔptkA exhibited the opposite effect, stronger expression of scoC and lower production of the exoprotease. Interestingly, both SalA and PtkA contain the same ATP-binding Walker domain and have thus presumably arisen from the common ancestral protein. Their regulatory interplay seems to be conserved in other bacteria.
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Affiliation(s)
- Abderahmane Derouiche
- Systems and Synthetic Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, 41296, Sweden
| | - Lei Shi
- Systems and Synthetic Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, 41296, Sweden
| | - Vladimir Bidnenko
- Micalis UMR1319, Institut National de la Recherche Agronomique, Jouy-en-Josas, 78350, France
| | - Magali Ventroux
- Micalis UMR1319, Institut National de la Recherche Agronomique, Jouy-en-Josas, 78350, France
| | - Nathalie Pigonneau
- Micalis UMR1319, Institut National de la Recherche Agronomique, Jouy-en-Josas, 78350, France
| | | | - Aida Kalantari
- Systems and Synthetic Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, 41296, Sweden
| | - Sylvie Nessler
- Institut de Biochimie et Biophysique Moléculaire et Cellulaire, University Paris-Sud, Orsay, 91405, France
| | | | - Ivan Mijakovic
- Systems and Synthetic Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, 41296, Sweden
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19
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Kang HJ, Gilbert C, Badeaux F, Atlan D, LaPointe G. A tyrosine phosphorylation switch controls the interaction between the transmembrane modulator protein Wzd and the tyrosine kinase Wze of Lactobacillus rhamnosus. BMC Microbiol 2015; 15:40. [PMID: 25885688 PMCID: PMC4340800 DOI: 10.1186/s12866-015-0371-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 02/04/2015] [Indexed: 04/27/2023] Open
Abstract
Background One proposed mechanism for assembly of secreted heteropolysaccharides by many Gram positive bacteria relies on the coordinated action of a polymerization complex through reversible phosphorylation events. The role of the tyrosine protein kinase transmembrane modulator is, however, not well understood. Results The protein sequences deduced from the wzb, wzd and wze genes from Lactobacillus rhamnosus ATCC 9595 and RW-9595 M contain motifs also found in corresponding proteins CpsB, CpsC and CpsD from Streptococcus pneumoniae D39 (serotype 2). Use of an anti-phosphotyrosine antibody demonstrated that both Wzd and Wze can be found in tyrosine phosphorylated form. When tyrosine 266 was mutated to phenylalanine, WzdY266F showed slightly less phosphorylated protein than those produced by using eight other tyrosine mutated Wzd genes, when expressed along with Wze and Wzb in Lactococcus lactis subsp. cremoris MG1363. In order to demonstrate the importance of ATP for the interactions among these proteins, native and fusion Wzb, Wzd and Wze proteins were expressed and purified from Escherichia coli cultures. The modulator protein, Wzd, binds with the phosphotyrosine kinase Wze, irrespective of its phosphorylation status. However, Wze attained a higher phosphorylation level after interacting with phosphorylated Wzd in the presence of 10 mM ATP. This highly phosphorylated Wze did not remain in close association with phosphorylated Wzd. Conclusion The Wze tyrosine kinase protein of Lactobacillus rhamnosus thus carries out tyrosine phosphorylation of Wzd in addition to auto- and trans- phosphorylation of the kinase itself. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0371-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hye-Ji Kang
- STELA Dairy Research Centre, INAF, Université Laval, Québec, G1V 0A6, QC, Canada. .,Present address: Academy of Immunology and Microbiology (AIM), Institute for Basic Science (IBS), Pohang, 790-784, Republic of Korea.
| | - Christophe Gilbert
- CIRI-U1111 INSERM- UMR5308 CNRS-UCBL-ENSL, Université de Lyon, Université Lyon 1, 10 rue Dubois, bât. Lwoff, F-69622, Villeurbanne cedex, France.
| | - Frédérique Badeaux
- STELA Dairy Research Centre, INAF, Université Laval, Québec, G1V 0A6, QC, Canada.
| | - Danièle Atlan
- CNRS, UMR5240, Unité microbiologie, adaptation et pathogénie, Villeurbanne, F-69622, France.
| | - Gisèle LaPointe
- STELA Dairy Research Centre, INAF, Université Laval, Québec, G1V 0A6, QC, Canada.
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20
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Toniolo C, Balducci E, Romano MR, Proietti D, Ferlenghi I, Grandi G, Berti F, Ros IMY, Janulczyk R. Streptococcus agalactiae capsule polymer length and attachment is determined by the proteins CpsABCD. J Biol Chem 2015; 290:9521-32. [PMID: 25666613 DOI: 10.1074/jbc.m114.631499] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Indexed: 11/06/2022] Open
Abstract
The production of capsular polysaccharides (CPS) or secreted exopolysaccharides is ubiquitous in bacteria, and the Wzy pathway constitutes a prototypical mechanism to produce these structures. Despite the differences in polysaccharide composition among species, a group of proteins involved in this pathway is well conserved. Streptococcus agalactiae (group B Streptococcus; GBS) produces a CPS that represents the main virulence factor of the bacterium and is a prime target in current vaccine development. We used this human pathogen to investigate the roles and potential interdependencies of the conserved proteins CpsABCD encoded in the cps operon, by developing knock-out and functional mutant strains. The mutant strains were examined for CPS quantity, size, and attachment to the cell surface as well as CpsD phosphorylation. We observed that CpsB, -C, and -D compose a phosphoregulatory system where the CpsD autokinase phosphorylates its C-terminal tyrosines in a CpsC-dependent manner. These Tyr residues are also the target of the cognate CpsB phosphatase. An interaction between CpsD and CpsC was observed, and the phosphorylation state of CpsD influenced the subsequent action of CpsC. The CpsC extracellular domain appeared necessary for the production of high molecular weight polysaccharides by influencing CpsA-mediated attachment of the CPS to the bacterial cell surface. In conclusion, although having no impact on cps transcription or the synthesis of the basal repeating unit, we suggest that these proteins are fine-tuning the last steps of CPS biosynthesis (i.e. the balance between polymerization and attachment to the cell wall).
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Affiliation(s)
- Chiara Toniolo
- From Novartis Vaccines and Diagnostics, Research Center, Via Fiorentina 1, 53100 Siena, Italy
| | - Evita Balducci
- From Novartis Vaccines and Diagnostics, Research Center, Via Fiorentina 1, 53100 Siena, Italy
| | - Maria Rosaria Romano
- From Novartis Vaccines and Diagnostics, Research Center, Via Fiorentina 1, 53100 Siena, Italy
| | - Daniela Proietti
- From Novartis Vaccines and Diagnostics, Research Center, Via Fiorentina 1, 53100 Siena, Italy
| | - Ilaria Ferlenghi
- From Novartis Vaccines and Diagnostics, Research Center, Via Fiorentina 1, 53100 Siena, Italy
| | - Guido Grandi
- From Novartis Vaccines and Diagnostics, Research Center, Via Fiorentina 1, 53100 Siena, Italy
| | - Francesco Berti
- From Novartis Vaccines and Diagnostics, Research Center, Via Fiorentina 1, 53100 Siena, Italy
| | | | - Robert Janulczyk
- From Novartis Vaccines and Diagnostics, Research Center, Via Fiorentina 1, 53100 Siena, Italy
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21
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Modification of the CpsA protein reveals a role in alteration of the Streptococcus agalactiae cell envelope. Infect Immun 2015; 83:1497-506. [PMID: 25644003 DOI: 10.1128/iai.02656-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The bacterial cell envelope is a crucial first line of defense for a systemic pathogen, with production of capsular polysaccharides and maintenance of the peptidoglycan cell wall serving essential roles in survival in the host environment. The LytR-CpsA-Psr proteins are important for cell envelope maintenance in many Gram-positive species. In this study, we examined the role of the extracellular domain of the CpsA protein of the zoonotic pathogen group B Streptococcus in capsule production and cell wall integrity. CpsA has multiple functional domains, including a DNA-binding/transcriptional activation domain and a large extracellular domain. We demonstrated that episomal expression of extracellularly truncated CpsA causes a dominant-negative effect on capsule production when expressed in the wild-type strain. Regions of the extracellular domain essential to this phenotype were identified. The dominant-negative effect could be recapitulated by addition of purified CpsA protein or a short CpsA peptide to cultures of wild-type bacteria. Changes in cell wall morphology were also observed when the dominant-negative peptide was added to wild-type cultures. Fluorescently labeled CpsA peptide could be visualized bound at the mid-cell region near the division septae, suggesting a novel role for CpsA in cell division. Finally, expression of truncated CpsA also led to attenuation of virulence in zebrafish models of infection, to levels below that of a cpsA deletion strain, demonstrating the key role of the extracellular domain in virulence of GBS.
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22
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Ramirez M. Streptococcus pneumoniae. MOLECULAR MEDICAL MICROBIOLOGY 2015:1529-1546. [DOI: 10.1016/b978-0-12-397169-2.00086-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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23
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Catalão MJ, Figueiredo J, Henriques MX, Gomes JP, Filipe SR. Optimization of fluorescent tools for cell biology studies in Gram-positive bacteria. PLoS One 2014; 9:e113796. [PMID: 25464377 PMCID: PMC4252051 DOI: 10.1371/journal.pone.0113796] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 10/30/2014] [Indexed: 11/23/2022] Open
Abstract
The understanding of how Gram-positive bacteria divide and ensure the correct localization of different molecular machineries, such as those involved in the synthesis of the bacterial cell surface, is crucial to design strategies to fight bacterial infections. In order to determine the correct subcellular localization of fluorescent proteins in Streptococcus pneumoniae, we have previously described tools to express derivatives of four fluorescent proteins, mCherry, Citrine, CFP and GFP, to levels that allow visualization by fluorescence microscopy, by fusing the first ten amino acids of the S. pneumoniae protein Wze (the i-tag), upstream of the fluorescent protein. Here, we report that these tools can also be used in other Gram-positive bacteria, namely Lactococcus lactis, Staphylococcus aureus and Bacillus subtilis, possibly due to optimized translation rates. Additionally, we have optimized the i-tag by testing the effect of the first ten amino acids of other pneumococcal proteins in the increased expression of the fluorescent protein Citrine. We found that manipulating the structure and stability of the 5′ end of the mRNA molecule, which may influence the accessibility of the ribosome, is determinant to ensure the expression of a strong fluorescent signal.
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Affiliation(s)
- Maria João Catalão
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Apartado 127, 2781-901 Oeiras, Portugal
| | - Joana Figueiredo
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Apartado 127, 2781-901 Oeiras, Portugal
| | - Mafalda X. Henriques
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Apartado 127, 2781-901 Oeiras, Portugal
| | - João Paulo Gomes
- National Institute of Health, Department of Infectious Diseases, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - Sérgio R. Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, Apartado 127, 2781-901 Oeiras, Portugal
- * E-mail:
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24
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Topology of Streptococcus pneumoniae CpsC, a polysaccharide copolymerase and bacterial protein tyrosine kinase adaptor protein. J Bacteriol 2014; 197:120-7. [PMID: 25313397 DOI: 10.1128/jb.02106-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Gram-positive bacteria, tyrosine kinases are split into two proteins, the cytoplasmic tyrosine kinase and a transmembrane adaptor protein. In Streptococcus pneumoniae, this transmembrane adaptor is CpsC, with the C terminus of CpsC critical for interaction and subsequent tyrosine kinase activity of CpsD. Topology predictions suggest that CpsC has two transmembrane domains, with the N and C termini present in the cytoplasm. In order to investigate CpsC topology, we used a chromosomal hemagglutinin (HA)-tagged Cps2C protein in S. pneumoniae strain D39. Incubation of both protoplasts and membranes with carboxypeptidase B (CP-B) resulted in complete degradation of HA-Cps2C in all cases, indicating that the C terminus of Cps2C was likely extracytoplasmic and hence that the protein's topology was not as predicted. Similar results were seen with membranes from S. pneumoniae strain TIGR4, indicating that Cps4C also showed similar topology. A chromosomally encoded fusion of HA-Cps2C and Cps2D was not degraded by CP-B, suggesting that the fusion fixed the C terminus within the cytoplasm. However, capsule synthesis was unaltered by this fusion. Detection of the CpsC C terminus by flow cytometry indicated that it was extracytoplasmic in approximately 30% of cells. Interestingly, a mutant in the protein tyrosine phosphatase CpsB had a significantly greater proportion of positive cells, although this effect was independent of its phosphatase activity. Our data indicate that CpsC possesses a varied topology, with the C terminus flipping across the cytoplasmic membrane, where it interacts with CpsD in order to regulate tyrosine kinase activity.
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25
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Standish AJ, Whittall JJ, Morona R. Tyrosine phosphorylation enhances activity of pneumococcal autolysin LytA. MICROBIOLOGY-SGM 2014; 160:2745-2754. [PMID: 25288646 DOI: 10.1099/mic.0.080747-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Tyrosine phosphorylation has long been recognized as a crucial post-translational regulatory mechanism in eukaryotes. However, only in the past decade has recognition been given to the crucial importance of bacterial tyrosine phosphorylation as an important regulatory feature of pathogenesis. This study describes the effect of tyrosine phosphorylation on the activity of a major virulence factor of the pneumococcus, the autolysin LytA, and a possible connection to the Streptococcus pneumoniae capsule synthesis regulatory proteins (CpsB, CpsC and CpsD). We show that in vitro pneumococcal tyrosine kinase, CpsD, and the protein tyrosine phosphatase, CpsB, act to phosphorylate and dephosphorylate LytA. Furthermore, this modulates LytA function in vitro with phosphorylated LytA binding more strongly to the choline analogue DEAE. A phospho-mimetic (Y264E) mutation of the LytA phosphorylation site displayed similar phenotypes as well as an enhanced dimerization capacity. Similarly, tyrosine phosphorylation increased LytA amidase activity, as evidenced by a turbidometric amidase activity assay. Similarly, when the phospho-mimetic mutation was introduced in the chromosomal lytA of S. pneumoniae, autolysis occurred earlier and at an enhanced rate. This study thus describes, to our knowledge, the first functional regulatory effect of tyrosine phosphorylation on a non-capsule-related protein in the pneumococcus, and suggests a link between the regulation of LytA-dependent autolysis of the cell and the biosynthesis of capsular polysaccharide.
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Affiliation(s)
- Alistair J Standish
- School of Molecular and Biomedical Sciences, University of Adelaide, SA 5005, Australia
| | - Jonathan J Whittall
- School of Molecular and Biomedical Sciences, University of Adelaide, SA 5005, Australia
| | - Renato Morona
- School of Molecular and Biomedical Sciences, University of Adelaide, SA 5005, Australia
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26
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Atilano ML, Pereira PM, Vaz F, Catalão MJ, Reed P, Grilo IR, Sobral RG, Ligoxygakis P, Pinho MG, Filipe SR. Bacterial autolysins trim cell surface peptidoglycan to prevent detection by the Drosophila innate immune system. eLife 2014; 3:e02277. [PMID: 24692449 PMCID: PMC3971415 DOI: 10.7554/elife.02277] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Bacteria have to avoid recognition by the host immune system in order to establish a successful infection. Peptidoglycan, the principal constituent of virtually all bacterial surfaces, is a specific molecular signature recognized by dedicated host receptors, present in animals and plants, which trigger an immune response. Here we report that autolysins from Gram-positive pathogenic bacteria, enzymes capable of hydrolyzing peptidoglycan, have a major role in concealing this inflammatory molecule from Drosophila peptidoglycan recognition proteins (PGRPs). We show that autolysins trim the outermost peptidoglycan fragments and that in their absence bacterial virulence is impaired, as PGRPs can directly recognize leftover peptidoglycan extending beyond the external layers of bacterial proteins and polysaccharides. The activity of autolysins is not restricted to the producer cells but can also alter the surface of neighboring bacteria, facilitating the survival of the entire population in the infected host. DOI:http://dx.doi.org/10.7554/eLife.02277.001 While most bacteria are harmless, some can cause diseases as varied as food poisoning and meningitis, so our immune system has developed various ways of detecting and eliminating bacteria and other pathogens. Receptor proteins belonging to the immune system detect molecules that give away the presence of the bacteria and trigger an immune response targeted at the invading pathogen. Peptidoglycan is one telltale molecule that betrays the presence of bacteria. Peptidoglycan is found in the bacterial cell wall, and for many years it was assumed that the immune system detected stray fragments of peptidoglycan that were accidentally shed by the bacteria. However, it was later shown that the immune system could, under certain conditions, detect peptidoglycan when it is still part of the cell wall. This raised an interesting question: do bacteria use other methods to stop peptidoglycan being detected by the immune system? Now, Atilano, Pereira et al. have found that enzymes called autolysins can conceal bacteria from the receptor proteins that detect peptidoglycan. These enzymes are needed to break the bonds within the peptidoglycan present in the rigid bacterial cell wall to allow the bacteria to grow and divide. ‘Knocking out’ the genes for autolysins allowed the receptor proteins from the fruit fly, Drosophila, to bind to the bacteria; however, the mutant bacteria were able to evade the immune system after they had been treated with the purified enzymes. Atilano, Pereira et al. suggest that the autolysins trim the exposed ends of the peptidoglycan molecules on the surface of the cell wall, which could otherwise be detected by the host. The experiments also show that bacterial pathogens—including a strain of MRSA—with mutations that knock out autolysin activity trigger a stronger immune response in fruit flies, and are therefore less able to infect this host. Autolysins also help to conceal Streptococcus pneumoniae—a bacterial pathogen that is a common cause of pneumonia and infant deaths in developing countries—from detection by fruit flies. The findings of Atilano, Pereira et al. highlight how bacteria employ a number of ways to evade detection. If similar behavior is observed when bacteria infect humans, autolysins could represent a new drug target for the treatment of bacterial diseases. DOI:http://dx.doi.org/10.7554/eLife.02277.002
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Affiliation(s)
- Magda Luciana Atilano
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal.,Genes and Development Laboratory, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Pedro Matos Pereira
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Filipa Vaz
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Maria João Catalão
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Patricia Reed
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Inês Ramos Grilo
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Rita Gonçalves Sobral
- Departamento de Ciências da Vida, Centro de Recursos Microbiologicos (CREM), Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Petros Ligoxygakis
- Genes and Development Laboratory, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Mariana Gomes Pinho
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
| | - Sérgio Raposo Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa (ITQB-UNL), Oeiras, Portugal
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Evans K, Stone V, Chen L, Ge X, Xu P. Systematic study of genes influencing cellular chain length in Streptococcus sanguinis. MICROBIOLOGY-SGM 2013; 160:307-315. [PMID: 24295823 PMCID: PMC3919539 DOI: 10.1099/mic.0.071688-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Streptococcus sanguinis is a Gram-positive bacterium that is indigenous to the oral cavity. S. sanguinis, a primary colonizer of the oral cavity, serves as a tether for the attachment of other oral pathogens. The colonization of microbes on the tooth surface forms dental plaque, which can lead to the onset of periodontal disease. We examined a comprehensive mutant library to identify genes related to cellular chain length and morphology using phase-contrast microscopy. A number of hypothetical genes related to the cellular chain length were identified in this study. Genes related to the cellular chain length were analysed along with clusters of orthologous groups (COG) for gene functions. It was discovered that the highest proportion of COG functions related to cellular chain length was 'cell division and chromosome separation'. However, different COG functions were also found to be related with altered cellular chain length. This suggested that different genes related with multiple mechanisms contribute to the cellular chain length in S. sanguinis SK36.
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Affiliation(s)
- Karra Evans
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298-0566, USA
| | - Victoria Stone
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298-0566, USA
| | - Lei Chen
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298-0566, USA
| | - Xiuchun Ge
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298-0566, USA
| | - Ping Xu
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, VA 23298-0566, USA
- Center for the Study of Biological Complexity of Virginia Commonwealth University, Richmond, VA, USA
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
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Salzano AM, Novi G, Arioli S, Corona S, Mora D, Scaloni A. Mono-dimensional blue native-PAGE and bi-dimensional blue native/urea-PAGE or/SDS-PAGE combined with nLC–ESI-LIT-MS/MS unveil membrane protein heteromeric and homomeric complexes in Streptococcus thermophilus. J Proteomics 2013; 94:240-61. [DOI: 10.1016/j.jprot.2013.09.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/04/2013] [Accepted: 09/14/2013] [Indexed: 02/06/2023]
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Massidda O, Nováková L, Vollmer W. From models to pathogens: how much have we learned about Streptococcus pneumoniae cell division? Environ Microbiol 2013; 15:3133-57. [PMID: 23848140 DOI: 10.1111/1462-2920.12189] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 06/08/2013] [Accepted: 06/09/2013] [Indexed: 12/22/2022]
Abstract
Streptococcus pneumoniae is an oval-shaped Gram-positive coccus that lives in intimate association with its human host, both as a commensal and pathogen. The seriousness of pneumococcal infections and the spread of multi-drug resistant strains call for new lines of intervention. Bacterial cell division is an attractive target to develop antimicrobial drugs. This review discusses the recent advances in understanding S. pneumoniae growth and division, in comparison with the best studied rod-shaped models, Escherichia coli and Bacillus subtilis. To maintain their shape, these bacteria propagate by peripheral and septal peptidoglycan synthesis, involving proteins that assemble into distinct complexes called the elongasome and the divisome, respectively. Many of these proteins are conserved in S. pneumoniae, supporting the notion that the ovococcal shape is also achieved by rounds of elongation and division. Importantly, S. pneumoniae and close relatives with similar morphology differ in several aspects from the model rods. Overall, the data support a model in which a single large machinery, containing both the peripheral and septal peptidoglycan synthesis complexes, assembles at midcell and governs growth and division. The mechanisms generating the ovococcal or coccal shape in lactic-acid bacteria have likely evolved by gene reduction from a rod-shaped ancestor of the same group.
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Affiliation(s)
- Orietta Massidda
- Department of Surgical Sciences, University of Cagliari, Via Porcell, 4, 09100, Cagliari, Italy
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Javens J, Wan Z, Hardy GG, Brun YV. Bypassing the need for subcellular localization of a polysaccharide export-anchor complex by overexpressing its protein subunits. Mol Microbiol 2013; 89:350-71. [PMID: 23714375 DOI: 10.1111/mmi.12281] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2013] [Indexed: 11/30/2022]
Abstract
Subcellular protein localization is thought to promote protein-protein interaction by increasing the effective concentration and enabling spatial co-ordination and proper segregation of proteins. We found that protein overexpression allowed the assembly of a productive polysaccharide biosynthesis-export-anchoring complex in the absence of polar localization in Caulobacter crescentus. Polar localization of the holdfast export protein, HfsD, depends on the presence of the other export proteins, HfsA and HfsB, and on the polar scaffold protein PodJ. The holdfast deficiency of hfsB and podJ mutants is suppressed by the overexpression of export proteins. Restored holdfasts are randomly positioned and colocalize with a holdfast anchor protein in these strains, indicating that functional complexes can form at non-polar sites. Therefore, overexpression of export proteins surpasses a concentration threshold necessary for holdfast synthesis. Restoration of holdfast synthesis at non-polar sites reduces surface adhesion, consistent with the need to spatially co-ordinate the holdfast synthesis machinery with the flagellum and pili. These strains lack the cell-specific segregation of the holdfast, resulting in the presence of holdfasts in motile daughter cells. Our results highlight the fact that multiple facets of subcellular localization can be coupled to improve the phenotypic outcome of a protein assembly.
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Affiliation(s)
- June Javens
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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31
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Domingues S, Aires AC, Mohedano ML, López P, Arraiano CM. A new tool for cloning and gene expression in Streptococcus pneumoniae. Plasmid 2013; 70:247-53. [PMID: 23707902 DOI: 10.1016/j.plasmid.2013.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 05/07/2013] [Accepted: 05/10/2013] [Indexed: 11/30/2022]
Abstract
A new replicon suitable for cloning and gene expression was successfully introduced into Streptococcus pneumoniae. The non-integrative lactococcal vectors pIL253 (higher-copy) and pIL252 (lower-copy), which are based on the promiscuous theta-replicating plasmid pAMβ1, were established in pneumococcus. The stability and the small size of these plasmids, together with the presence of a helpful multi-cloning site make them a useful genetic tool for gene expression in this bacterium. The functionality of the system was tested by cloning and expressing the pneumococcal RNase R gene in pIL253. Full constitutive expression of the cloned gene was observed, clearly demonstrating that this plasmid can be used as an expression vector in S. pneumoniae. Moreover, gene expression can be regulated by the use of the lower- or higher-copy number vector versions. The existence of other replicative plasmids based on this family, which are also probably functional in pneumococcus, further broadens the cloning possibilities. We also show that S. pneumoniae cells can accommodate simultaneously pIL252 or pIL253 together with pLS1, a pMV158 derivative, which replicates via a rolling circle mechanism. This fact greatly increases the ability to manipulate this bacterium. The availability of a new family of replicative vectors for genetic manipulation in S. pneumoniae is an important contribution to the study of this pathogenic microorganism.
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Affiliation(s)
- Susana Domingues
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
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Henriques MX, Catalão MJ, Figueiredo J, Gomes JP, Filipe SR. Construction of improved tools for protein localization studies in Streptococcus pneumoniae. PLoS One 2013; 8:e55049. [PMID: 23349996 PMCID: PMC3551898 DOI: 10.1371/journal.pone.0055049] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 12/18/2012] [Indexed: 12/01/2022] Open
Abstract
We have constructed a set of plasmids that allow efficient expression of both N- and C-terminal fusions of proteins of interest to fluorescent proteins mCherry, Citrine, CFP and GFP in the Gram-positive pathogen Streptococcus pneumoniae. In order to improve expression of the fluorescent fusions to levels that allow their detection by fluorescence microscopy, we have introduced a 10 amino acid tag, named i-tag, at the N-terminal end of the fluorescent proteins. This caused increased expression due to improved translation efficiency and did not interfere with the protein localization in pneumococcal bacteria. Localizing fluorescent derivatives of FtsZ, Wzd and Wze in dividing bacteria validated the developed tools. The availability of the new plasmids described in this work should greatly facilitate studies of protein localization in an important clinical pathogen.
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Affiliation(s)
- Mafalda X. Henriques
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Maria João Catalão
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Joana Figueiredo
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - João Paulo Gomes
- Department of Infections Diseases, National Institute of Health, Lisbon, Portugal
| | - Sergio R. Filipe
- Laboratory of Bacterial Cell Surfaces and Pathogenesis, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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Trihn M, Ge X, Dobson A, Kitten T, Munro CL, Xu P. Two-component system response regulators involved in virulence of Streptococcus pneumoniae TIGR4 in infective endocarditis. PLoS One 2013; 8:e54320. [PMID: 23342132 PMCID: PMC3546988 DOI: 10.1371/journal.pone.0054320] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/10/2012] [Indexed: 11/19/2022] Open
Abstract
Streptococci resident in the oral cavity have been linked to infective endocarditis (IE). While other viridans streptococci are commonly studied in relation to IE, less research has been focused on Streptococcus pneumoniae. We established for the first time an animal model of S. pneumoniae IE, and examined the virulence of the TIGR4 strain in this model. We hypothesized that two-component systems (TCS) may mediate S. pneumoniae TIGR4 strain virulence in IE and examined TCS response regulator (RR) mutants of TIGR4 in vivo with the IE model. Thirteen of the 14 RR protein genes were mutagenized, excluding only the essential gene SP_1227. The requirement of the 13 RRs for S. pneumoniae competitiveness in the IE model was assessed in vivo through use of quantitative real-time PCR (qPCR) and competitive index assays. Using real-time PCR, several RR mutants were detected at significantly lower levels in infected heart valves compared with a control strain suggesting the respective RRs are candidate virulence factors for IE. The virulence reduction of the ΔciaR mutant was further confirmed by competitive index assay. Our data suggest that CiaR is a virulence factor of S. pneumoniae strain TIGR4 for IE.
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Affiliation(s)
- My Trihn
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Xiuchun Ge
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Alleson Dobson
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Todd Kitten
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Cindy L. Munro
- The College of Nursing, University of South Florida, Tampa, Florida, United States of America
| | - Ping Xu
- VCU Philips Institute of Oral and Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Grangeasse C, Nessler S, Mijakovic I. Bacterial tyrosine kinases: evolution, biological function and structural insights. Philos Trans R Soc Lond B Biol Sci 2012; 367:2640-55. [PMID: 22889913 DOI: 10.1098/rstb.2011.0424] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Reversible protein phosphorylation is a major mechanism in the regulation of fundamental signalling events in all living organisms. Bacteria have been shown to possess a versatile repertoire of protein kinases, including histidine and aspartic acid kinases, serine/threonine kinases, and more recently tyrosine and arginine kinases. Tyrosine phosphorylation is today recognized as a key regulatory device of bacterial physiology, linked to exopolysaccharide production, virulence, stress response and DNA metabolism. However, bacteria have evolved tyrosine kinases that share no resemblance with their eukaryotic counterparts and are unique in exploiting the ATP/GTP-binding Walker motif to catalyse autophosphorylation and substrate phosphorylation on tyrosine. These enzymes, named BY-kinases (for Bacterial tYrosine kinases), have been identified in a majority of sequenced bacterial genomes, and to date no orthologues have been found in Eukarya. The aim of this review was to present the most recent knowledge about BY-kinases by focusing primarily on their evolutionary origin, structural and functional aspects, and emerging regulatory potential based on recent bacterial phosphoproteomic studies.
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Affiliation(s)
- Christophe Grangeasse
- Bases Moléculaires et Structurales des Systèmes Infectieux, IBCP, CNRS, Université de Lyon, UMR 5086, 7 passage du Vercors, 69367 Lyon, France.
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Standish AJ, Salim AA, Zhang H, Capon RJ, Morona R. Chemical inhibition of bacterial protein tyrosine phosphatase suppresses capsule production. PLoS One 2012; 7:e36312. [PMID: 22629313 PMCID: PMC3356977 DOI: 10.1371/journal.pone.0036312] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Accepted: 04/01/2012] [Indexed: 12/12/2022] Open
Abstract
Capsule polysaccharide is a major virulence factor for a wide range of bacterial pathogens, including Streptococcus pneumoniae. The biosynthesis of Wzy-dependent capsules in both gram-negative and -positive bacteria is regulated by a system involving a protein tyrosine phosphatase (PTP) and a protein tyrosine kinase. However, how the system functions is still controversial. In Streptococcus pneumoniae, a major human pathogen, the system is present in all but 2 of the 93 serotypes found to date. In order to study this regulation further, we performed a screen to find inhibitors of the phosphatase, CpsB. This led to the observation that a recently discovered marine sponge metabolite, fascioquinol E, inhibited CpsB phosphatase activity both in vitro and in vivo at concentrations that did not affect the growth of the bacteria. This inhibition resulted in decreased capsule synthesis in D39 and Type 1 S. pneumoniae. Furthermore, concentrations of Fascioquinol E that inhibited capsule also lead to increased attachment of pneumococci to a macrophage cell line, suggesting that this compound would inhibit the virulence of the pathogen. Interestingly, this compound also inhibited the phosphatase activity of the structurally unrelated gram-negative PTP, Wzb, which belongs to separate family of protein tyrosine phosphatases. Furthermore, incubation with Klebsiella pneumoniae, which contains a homologous phosphatase, resulted in decreased capsule synthesis. Taken together, these data provide evidence that PTPs are critical for Wzy-dependent capsule production across a spectrum of bacteria, and as such represents a valuable new molecular target for the development of anti-virulence antibacterials.
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Affiliation(s)
- Alistair J Standish
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia.
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Eberhardt A, Hoyland CN, Vollmer D, Bisle S, Cleverley RM, Johnsborg O, Håvarstein LS, Lewis RJ, Vollmer W. Attachment of capsular polysaccharide to the cell wall in Streptococcus pneumoniae. Microb Drug Resist 2012; 18:240-55. [PMID: 22432711 DOI: 10.1089/mdr.2011.0232] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Streptococcus pneumoniae protects itself from components of the human immune defense system by a thick polysaccharide capsule, which in most serotypes is covalently attached to the cell wall peptidoglycan. Members of the LytR-Cps2A-Psr (LCP) protein family have recently been implicated in the attachment of anionic polymers to peptidoglycan in Gram-positive bacteria, based on genetic evidence from Bacillus subtilis mutant strains and on the crystal structure of S. pneumoniae Cps2A containing a tightly bound polyprenol (pyro)phosphate lipid. Here, we provide evidence that Cps2A and its two pneumococcal homologs, LytR and Psr, contribute to the maintenance of normal capsule levels and to the retention of the capsular polysaccharide at the cell wall in the capsular type 2 S. pneumoniae strain D39. GFP fusions of all three LCP proteins showed enhanced localization at mid-cell, indicating a role in cell wall growth. Single cps2A or psr mutants produced a reduced amount of capsule. A cps2A lytR double mutant showed greatly impaired growth and cell morphology and lost approximately half of the total capsule material into the culture supernatant. We also present the crystal structure of the B. subtilis LCP protein YwtF and provide crystallographic evidence for the phosphotransferase activity of Cps2A, supporting an enzymatic function in the attachment of capsular polysaccharides to cell wall peptidoglycan.
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Affiliation(s)
- Alice Eberhardt
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University , Newcastle upon Tyne, United Kingdom
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Glutamine synthetase and glucose-6-phosphate isomerase are adhesive moonlighting proteins of Lactobacillus crispatus released by epithelial cathelicidin LL-37. J Bacteriol 2012; 194:2509-19. [PMID: 22389474 DOI: 10.1128/jb.06704-11] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glutamine synthetase (GS) and glucose-6-phosphate isomerase (GPI) were identified as novel adhesive moonlighting proteins of Lactobacillus crispatus ST1. Both proteins were bound onto the bacterial surface at acidic pHs, whereas a suspension of the cells to pH 8 caused their release into the buffer, a pattern previously observed with surface-bound enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of L. crispatus. The pH shift was associated with a rapid and transient increase in cell wall permeability, as measured by cell staining with propidium iodide. A gradual increase in the release of the four moonlighting proteins was also observed after the treatment of L. crispatus ST1 cells with increasing concentrations of the antimicrobial cationic peptide LL-37, which kills bacteria by disturbing membrane integrity and was here observed to increase the cell wall permeability of L. crispatus ST1. At pH 4, the fusion proteins His(6)-GS, His(6)-GPI, His(6)-enolase, and His(6)-GAPDH showed localized binding to cell division septa and poles of L. crispatus ST1 cells, whereas no binding to Lactobacillus rhamnosus GG was detected. Strain ST1 showed a pH-dependent adherence to the basement membrane preparation Matrigel. Purified His(6)-GS and His(6)-GPI proteins bound to type I collagen, and His(6)-GS also bound to laminin, and their level of binding was higher at pH 5.5 than at pH 6.5. His(6)-GS also expressed a plasminogen receptor function. The results show the strain-dependent surface association of moonlighting proteins in lactobacilli and that these proteins are released from the L. crispatus surface after cell trauma, under conditions of alkaline stress, or in the presence of the antimicrobial peptide LL-37 produced by human cells.
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