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Mkhayar K, Daoui O, Haloui R, Elkhattabi K, Elabbouchi A, Chtita S, Samadi A, Elkhattabi S. Ligand-Based Design of Novel Quinoline Derivatives as Potential Anticancer Agents: An In-Silico Virtual Screening Approach. Molecules 2024; 29:426. [PMID: 38257339 PMCID: PMC10819159 DOI: 10.3390/molecules29020426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/03/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
In this study, using the Comparative Molecular Field Analysis (CoMFA) approach, the structure-activity relationship of 33 small quinoline-based compounds with biological anti-gastric cancer activity in vitro was analyzed in 3D space. Once the 3D geometric and energy structure of the target chemical library has been optimized and their steric and electrostatic molecular field descriptions computed, the ideal 3D-QSAR model is generated and matched using the Partial Least Squares regression (PLS) algorithm. The accuracy, statistical precision, and predictive power of the developed 3D-QSAR model were confirmed by a range of internal and external validations, which were interpreted by robust correlation coefficients (RTrain2=0.931; Qcv2=0.625; RTest2=0.875). After carefully analyzing the contour maps produced by the trained 3D-QSAR model, it was discovered that certain structural characteristics are beneficial for enhancing the anti-gastric cancer properties of Quinoline derivatives. Based on this information, a total of five new quinoline compounds were developed, with their biological activity improved and their drug-like bioavailability measured using POM calculations. To further explore the potential of these compounds, molecular docking and molecular dynamics simulations were performed in an aqueous environment for 100 nanoseconds, specifically targeting serine/threonine protein kinase. Overall, the new findings of this study can serve as a starting point for further experiments with a view to the identification and design of a potential next-generation drug for target therapy against cancer.
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Affiliation(s)
- Khaoula Mkhayar
- Laboratory of Engineering, Systems and Applications, National School of Applied Sciences, Sidi Mohamed Ben Abdellah-Fez University, Fez 30000, Morocco; (K.M.); (O.D.); (R.H.)
| | - Ossama Daoui
- Laboratory of Engineering, Systems and Applications, National School of Applied Sciences, Sidi Mohamed Ben Abdellah-Fez University, Fez 30000, Morocco; (K.M.); (O.D.); (R.H.)
| | - Rachid Haloui
- Laboratory of Engineering, Systems and Applications, National School of Applied Sciences, Sidi Mohamed Ben Abdellah-Fez University, Fez 30000, Morocco; (K.M.); (O.D.); (R.H.)
| | - Kaouakeb Elkhattabi
- Laboratory for Oral Biology and Biotechnology Research, Department of Fundamental Sciences, Faculty of Medicine Dentistry, Mohammed V University, Rabat 10106, Morocco;
| | - Abdelmoula Elabbouchi
- Euromed Research Center, Euromed Faculty of Pharmacy, Euromed University of Fes (UEMF), Meknes Road, Fez 30000, Morocco;
| | - Samir Chtita
- Laboratory of Analytical and Molecular Chemistry, Faculty of Sciences Ben M’Sik, Hassan II University of Casablanca, Casablanca P.O. Box 7955, Morocco;
| | - Abdelouahid Samadi
- Department of Chemistry, College of Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Souad Elkhattabi
- Laboratory of Engineering, Systems and Applications, National School of Applied Sciences, Sidi Mohamed Ben Abdellah-Fez University, Fez 30000, Morocco; (K.M.); (O.D.); (R.H.)
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2
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Van Raad D, Huber T. eCell Technology for Cell-Free Protein Synthesis, Biosensing, and Remediation. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 185:129-146. [PMID: 37306701 DOI: 10.1007/10_2023_225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The eCell technology is a recently introduced, specialized protein production platform with uses in a multitude of biotechnological applications. This chapter summarizes the use of eCell technology in four selected application areas. Firstly, for detecting heavy metal ions, specifically mercury, in an in vitro protein expression system. Results show improved sensitivity and lower limit of detection compared to comparable in vivo systems. Secondly, eCells are semipermeable, stable, and can be stored for extended periods of time, making them a portable and accessible technology for bioremediation of toxicants in extreme environments. Thirdly and fourthly, applications of eCell technology are shown to facilitate expression of correctly folded disulfide-rich proteins and incorporate chemically interesting derivatives of amino acids into proteins which are toxic to in vivo protein expression. Overall, eCell technology presents a cost-effective and efficient method for biosensing, bioremediation, and protein production.
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Affiliation(s)
- Damian Van Raad
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT, Australia.
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3
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Ulrych A, Fabrik I, Kupčík R, Vajrychová M, Doubravová L, Branny P. Cell Wall Stress Stimulates the Activity of the Protein Kinase StkP of Streptococcus pneumoniae, Leading to Multiple Phosphorylation. J Mol Biol 2021; 433:167319. [PMID: 34688688 DOI: 10.1016/j.jmb.2021.167319] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 10/06/2021] [Accepted: 10/15/2021] [Indexed: 12/28/2022]
Abstract
Streptococcus pneumoniae is an opportunistic human pathogen that encodes a single eukaryotic-type Ser/Thr protein kinase StkP and its functional counterpart, the protein phosphatase PhpP. These signaling enzymes play critical roles in coordinating cell division and growth in pneumococci. In this study, we determined the proteome and phosphoproteome profiles of relevant mutants. Comparison of those with the wild-type provided a representative dataset of novel phosphoacceptor sites and StkP-dependent substrates. StkP phosphorylates key proteins involved in cell division and cell wall biosynthesis in both the unencapsulated laboratory strain Rx1 and the encapsulated virulent strain D39. Furthermore, we show that StkP plays an important role in triggering an adaptive response induced by a cell wall-directed antibiotic. Phosphorylation of the sensor histidine kinase WalK and downregulation of proteins of the WalRK core regulon suggest crosstalk between StkP and the WalRK two-component system. Analysis of proteomic profiles led to the identification of gene clusters regulated by catabolite control mechanisms, indicating a tight coupling of carbon metabolism and cell wall homeostasis. The imbalance of steady-state protein phosphorylation in the mutants as well as after antibiotic treatment is accompanied by an accumulation of the global Spx regulator, indicating a Spx-mediated envelope stress response. In summary, StkP relays the perceived signal of cell wall status to key cell division and regulatory proteins, controlling the cell cycle and cell wall homeostasis.
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Affiliation(s)
- Aleš Ulrych
- Institute of Microbiology, v.v.i., Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic.
| | - Ivo Fabrik
- Biomedical Research Center, University Hospital Hradec Králové, Sokolská 581, 500 05 Hradec Králové, Czech Republic.
| | - Rudolf Kupčík
- Biomedical Research Center, University Hospital Hradec Králové, Sokolská 581, 500 05 Hradec Králové, Czech Republic.
| | - Marie Vajrychová
- Biomedical Research Center, University Hospital Hradec Králové, Sokolská 581, 500 05 Hradec Králové, Czech Republic.
| | - Linda Doubravová
- Institute of Microbiology, v.v.i., Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic.
| | - Pavel Branny
- Institute of Microbiology, v.v.i., Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic.
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4
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Iannetta AA, Minton NE, Uitenbroek AA, Little JL, Stanton CR, Kristich CJ, Hicks LM. IreK-Mediated, Cell Wall-Protective Phosphorylation in Enterococcus faecalis. J Proteome Res 2021; 20:5131-5144. [PMID: 34672600 PMCID: PMC10037947 DOI: 10.1021/acs.jproteome.1c00635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Enterococcus faecalis is a Gram-positive bacterium that is a major cause of hospital-acquired infections due, in part, to its intrinsic resistance to cell wall-active antimicrobials. One critical determinant of this resistance is the transmembrane kinase IreK, which belongs to the penicillin-binding protein and serine/threonine kinase-associated kinase family of bacterial signaling proteins involved with the regulation of cell wall homeostasis. The activity of IreK is enhanced in response to cell wall stress, but direct substrates of IreK phosphorylation, leading to antimicrobial resistance, are largely unknown. To better understand stress-modulated phosphorylation events contributing to antimicrobial resistance, wild type E. faecalis cells treated with cell wall-active antimicrobials, chlorhexidine or ceftriaxone, were examined via phosphoproteomics. Among the most prominent changes was increased phosphorylation of divisome components after both treatments, suggesting that E. faecalis modulates cell division in response to cell wall stress. Phosphorylation mediated by IreK was then determined via a similar analysis with a E. faecalis ΔireK mutant strain, revealing potential IreK substrates involved with the regulation of peptidoglycan biosynthesis and within the E. faecalis CroS/R two-component system, another signal transduction pathway that promotes antimicrobial resistance. These results reveal critical insights into the biological functions of IreK.
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Affiliation(s)
- Anthony A. Iannetta
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Nicole E. Minton
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Alexis A. Uitenbroek
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Jaime L. Little
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Caroline R. Stanton
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Christopher J. Kristich
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226
| | - Leslie M. Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Li W, Yin Y, Meng Y, Ma Z, Lin H, Fan H. The phosphorylation of phosphoglucosamine mutase GlmM by Ser/Thr kinase STK mediates cell wall synthesis and virulence in Streptococcus suis serotype 2. Vet Microbiol 2021; 258:109102. [PMID: 33991786 DOI: 10.1016/j.vetmic.2021.109102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 05/05/2021] [Indexed: 10/21/2022]
Abstract
Streptococcus suis serotype 2 (SS2) is an important zoonotic pathogen that causes serious economic losses in the pig industry. Phosphorylation is an important mechanism of protein modification. Recent studies have reported that the serine/threonine kinase (STK) gene contributes to the growth and virulence of SS2. However, the mechanism underlying the regulatory functions of STK in SS2 has not been thoroughly elucidated to date. In this study, phosphoproteomic analysis was performed to determine substrates of the STK protein. Twenty-two proteins with different cell functions were identified as potential substrates of STK. Phosphoglucosamine mutase (GlmM) was selected for further investigation among them. In vitro phosphorylation assay and immunoprecipitation assay indicated that GlmM was phosphorylated by STK at the Ser-101 site and the phosphorylation level of GlmM can be affected. We observed that compared to the wild-type strain ZY05719, the glmM-deficient strain (ΔglmM) and the glmM S101A point mutation strain (CΔglmM S101A) showed aberrant cell morphology and attenuated virulence, including enlarged cell volume, absent capsule, decreased resistance, lower survival caused by unusual peptidoglycan synthesis, and significantly attenuated pathogenicity in a mouse infection model. Additionally, compared to ZY05719 and CΔglmM, GlmM enzyme acivities and peptidoglycan concentrations of the stk-deficient strain (Δstk), CΔglmM S101A decreased significantly. These experiments revealed that STK phosphorylates GlmM at the Ser-101 site to impact GlmM enzyme activity and control cell wall peptidoglycan synthesis to affect SS2 pathogenicity.
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Affiliation(s)
- Weiyi Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Yifan Yin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Yu Meng
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhe Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
| | - Huixing Lin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
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6
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Tripathi A, Kashyap A, Tripathi G, Yadav J, Bibban R, Aggarwal N, Thakur K, Chhokar A, Jadli M, Sah AK, Verma Y, Zayed H, Husain A, Bharti AC, Kashyap MK. Tumor reversion: a dream or a reality. Biomark Res 2021; 9:31. [PMID: 33958005 PMCID: PMC8101112 DOI: 10.1186/s40364-021-00280-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/30/2021] [Indexed: 02/07/2023] Open
Abstract
Reversion of tumor to a normal differentiated cell once considered a dream is now at the brink of becoming a reality. Different layers of molecules/events such as microRNAs, transcription factors, alternative RNA splicing, post-transcriptional, post-translational modifications, availability of proteomics, genomics editing tools, and chemical biology approaches gave hope to manipulation of cancer cells reversion to a normal cell phenotype as evidences are subtle but definitive. Regardless of the advancement, there is a long way to go, as customized techniques are required to be fine-tuned with precision to attain more insights into tumor reversion. Tumor regression models using available genome-editing methods, followed by in vitro and in vivo proteomics profiling techniques show early evidence. This review summarizes tumor reversion developments, present issues, and unaddressed challenges that remained in the uncharted territory to modulate cellular machinery for tumor reversion towards therapeutic purposes successfully. Ongoing research reaffirms the potential promises of understanding the mechanism of tumor reversion and required refinement that is warranted in vitro and in vivo models of tumor reversion, and the potential translation of these into cancer therapy. Furthermore, therapeutic compounds were reported to induce phenotypic changes in cancer cells into normal cells, which will contribute in understanding the mechanism of tumor reversion. Altogether, the efforts collectively suggest that tumor reversion will likely reveal a new wave of therapeutic discoveries that will significantly impact clinical practice in cancer therapy.
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Affiliation(s)
- Avantika Tripathi
- Amity Stem Cell Institute, Amity Medical School, Amity University Haryana, Panchgaon, Haryana, Manesar (Gurugram), -122413, India
| | - Anjali Kashyap
- Department of Biotechnology, Thapar Institute of Engineering & Technology, Patiala, Punjab, India
| | - Greesham Tripathi
- Amity Stem Cell Institute, Amity Medical School, Amity University Haryana, Panchgaon, Haryana, Manesar (Gurugram), -122413, India
| | - Joni Yadav
- Department of Zoology, Molecular Oncology Laboratory, University of Delhi (North Campus), New Delhi, 110007, India
| | - Rakhi Bibban
- Department of Zoology, Molecular Oncology Laboratory, University of Delhi (North Campus), New Delhi, 110007, India
| | - Nikita Aggarwal
- Department of Zoology, Molecular Oncology Laboratory, University of Delhi (North Campus), New Delhi, 110007, India
| | - Kulbhushan Thakur
- Department of Zoology, Molecular Oncology Laboratory, University of Delhi (North Campus), New Delhi, 110007, India
| | - Arun Chhokar
- Department of Zoology, Molecular Oncology Laboratory, University of Delhi (North Campus), New Delhi, 110007, India
| | - Mohit Jadli
- Department of Zoology, Molecular Oncology Laboratory, University of Delhi (North Campus), New Delhi, 110007, India
| | - Ashok Kumar Sah
- Department of Medical Laboratory Technology, Amity Medical School, Amity University Haryana, Panchgaon, Haryana, Manesar (Gurugram), India
- Department of Pathology and Laboratory Medicine, Medanta-The Medicity, Haryana, Gurugram, India
| | - Yeshvandra Verma
- Department of Toxicology, C C S University, Meerut, UP, 250004, India
| | - Hatem Zayed
- Department of Biomedical Sciences, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
| | - Amjad Husain
- Centre for Science & Society, Indian Institute of Science Education and Research (IISER), Bhopal, India
- Innovation and Incubation Centre for Entrepreneurship (IICE), Indian Institute of Science Education and Research (IISER), Bhopal, India
| | - Alok Chandra Bharti
- Department of Zoology, Molecular Oncology Laboratory, University of Delhi (North Campus), New Delhi, 110007, India.
| | - Manoj Kumar Kashyap
- Amity Stem Cell Institute, Amity Medical School, Amity University Haryana, Panchgaon, Haryana, Manesar (Gurugram), -122413, India.
- Department of Zoology, Molecular Oncology Laboratory, University of Delhi (North Campus), New Delhi, 110007, India.
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Bonne Køhler J, Jers C, Senissar M, Shi L, Derouiche A, Mijakovic I. Importance of protein Ser/Thr/Tyr phosphorylation for bacterial pathogenesis. FEBS Lett 2020; 594:2339-2369. [PMID: 32337704 DOI: 10.1002/1873-3468.13797] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/16/2020] [Accepted: 04/20/2020] [Indexed: 12/13/2022]
Abstract
Protein phosphorylation regulates a large variety of biological processes in all living cells. In pathogenic bacteria, the study of serine, threonine, and tyrosine (Ser/Thr/Tyr) phosphorylation has shed light on the course of infectious diseases, from adherence to host cells to pathogen virulence, replication, and persistence. Mass spectrometry (MS)-based phosphoproteomics has provided global maps of Ser/Thr/Tyr phosphosites in bacterial pathogens. Despite recent developments, a quantitative and dynamic view of phosphorylation events that occur during bacterial pathogenesis is currently lacking. Temporal, spatial, and subpopulation resolution of phosphorylation data is required to identify key regulatory nodes underlying bacterial pathogenesis. Herein, we discuss how technological improvements in sample handling, MS instrumentation, data processing, and machine learning should improve bacterial phosphoproteomic datasets and the information extracted from them. Such information is expected to significantly extend the current knowledge of Ser/Thr/Tyr phosphorylation in pathogenic bacteria and should ultimately contribute to the design of novel strategies to combat bacterial infections.
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Affiliation(s)
- Julie Bonne Køhler
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Carsten Jers
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Mériem Senissar
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Lei Shi
- Systems and Synthetic Biology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Abderahmane Derouiche
- Systems and Synthetic Biology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Ivan Mijakovic
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.,Systems and Synthetic Biology Division, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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Abstract
Reproduction in the bacterial kingdom predominantly occurs through binary fission-a process in which one parental cell is divided into two similarly sized daughter cells. How cell division, in conjunction with cell elongation and chromosome segregation, is orchestrated by a multitude of proteins has been an active area of research spanning the past few decades. Together, the monumental endeavors of multiple laboratories have identified several cell division and cell shape regulators as well as their underlying regulatory mechanisms in rod-shaped Escherichia coli and Bacillus subtilis, which serve as model organisms for Gram-negative and Gram-positive bacteria, respectively. Yet our understanding of bacterial cell division and morphology regulation is far from complete, especially in noncanonical and non-rod-shaped organisms. In this review, we focus on two proteins that are highly conserved in Gram-positive organisms, DivIVA and its homolog GpsB, and attempt to summarize the recent advances in this area of research and discuss their various roles in cell division, cell growth, and chromosome segregation in addition to their interactome and posttranslational regulation.
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Henry C, Haller L, Blein-Nicolas M, Zivy M, Canette A, Verbrugghe M, Mézange C, Boulay M, Gardan R, Samson S, Martin V, André-Leroux G, Monnet V. Identification of Hanks-Type Kinase PknB-Specific Targets in the Streptococcus thermophilus Phosphoproteome. Front Microbiol 2019; 10:1329. [PMID: 31275266 PMCID: PMC6593474 DOI: 10.3389/fmicb.2019.01329] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/28/2019] [Indexed: 12/17/2022] Open
Abstract
Protein phosphorylation especially on serine/threonine/tyrosine residues are frequent in many bacteria. This post-translational modification has been associated with pathogenicity and virulence in various species. However, only few data have been produced so far on generally recognized as safe bacteria used in food fermentations. A family of kinases known as Hanks-type kinases is suspected to be responsible for, at least, a part of these phosphorylations in eukaryotes as in bacteria. The objective of our work was to establish the first phosphoproteome of Streptococcus thermophilus, a lactic acid bacterium widely used in dairy fermentations in order to identified the proteins and pathways tagged by Ser/Thr/Tyr phosphorylations. In addition, we have evaluated the role in this process of the only Hanks-type kinase encoded in the S. thermophilus genome. We have constructed a mutant defective for the Hanks type kinase in S. thermophilus and established the proteomes and phosphoproteomes of the wild type and the mutant strains. To do that, we have enriched our samples in phosphopeptides with titane beads and used dimethyl tags to compare phosphopeptide abundances. Peptides and phosphopeptides were analyzed on a last generation LC-MS/MS system. We have identified and quantified 891 proteins representing half of the theoretical proteome. Among these proteins, 106 contained phosphorylated peptides. Various functional groups of proteins (amino acid, carbon and nucleotide metabolism, translation, cell cycle, stress response, …) were found phosphorylated. The phosphoproteome was only weakly reduced in the Hanks-type kinase mutant indicating that this enzyme is only one of the players in the phosphorylation process. The proteins that are modified by the Hanks-type kinase mainly belong to the divisome.
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Affiliation(s)
- Céline Henry
- Micalis Institute, PAPPSO, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Lucia Haller
- Micalis Institute, PAPPSO, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.,Micalis Institute, ComBac, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Mélisande Blein-Nicolas
- PAPPSO, GQE - Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Michel Zivy
- PAPPSO, GQE - Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Alexis Canette
- Micalis Institute, MIMA2, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Morgane Verbrugghe
- Micalis Institute, ComBac, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Christine Mézange
- Micalis Institute, ComBac, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Mylène Boulay
- Micalis Institute, ComBac, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Rozenn Gardan
- Micalis Institute, ComBac, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Samantha Samson
- MaIAGE, INRA, Université Paris-Saclay, Jouy-en-Josas, France
| | | | | | - Véronique Monnet
- Micalis Institute, PAPPSO, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.,Micalis Institute, ComBac, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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10
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Janczarek M, Vinardell JM, Lipa P, Karaś M. Hanks-Type Serine/Threonine Protein Kinases and Phosphatases in Bacteria: Roles in Signaling and Adaptation to Various Environments. Int J Mol Sci 2018; 19:ijms19102872. [PMID: 30248937 PMCID: PMC6213207 DOI: 10.3390/ijms19102872] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 12/19/2022] Open
Abstract
Reversible phosphorylation is a key mechanism that regulates many cellular processes in prokaryotes and eukaryotes. In prokaryotes, signal transduction includes two-component signaling systems, which involve a membrane sensor histidine kinase and a cognate DNA-binding response regulator. Several recent studies indicate that alternative regulatory pathways controlled by Hanks-type serine/threonine kinases (STKs) and serine/threonine phosphatases (STPs) also play an essential role in regulation of many different processes in bacteria, such as growth and cell division, cell wall biosynthesis, sporulation, biofilm formation, stress response, metabolic and developmental processes, as well as interactions (either pathogenic or symbiotic) with higher host organisms. Since these enzymes are not DNA-binding proteins, they exert the regulatory role via post-translational modifications of their protein targets. In this review, we summarize the current knowledge of STKs and STPs, and discuss how these enzymes mediate gene expression in prokaryotes. Many studies indicate that regulatory systems based on Hanks-type STKs and STPs play an essential role in the regulation of various cellular processes, by reversibly phosphorylating many protein targets, among them several regulatory proteins of other signaling cascades. These data show high complexity of bacterial regulatory network, in which the crosstalk between STK/STP signaling enzymes, components of TCSs, and the translational machinery occurs. In this regulation, the STK/STP systems have been proved to play important roles.
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Affiliation(s)
- Monika Janczarek
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland.
| | - José-María Vinardell
- Department of Microbiology, Faculty of Biology, University of Sevilla, Avda. Reina Mercedes 6, 41012 Sevilla, Spain.
| | - Paulina Lipa
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland.
| | - Magdalena Karaś
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland.
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11
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Ni H, Fan W, Li C, Wu Q, Hou H, Hu D, Zheng F, Zhu X, Wang C, Cao X, Shao ZQ, Pan X. Streptococcus suis DivIVA Protein Is a Substrate of Ser/Thr Kinase STK and Involved in Cell Division Regulation. Front Cell Infect Microbiol 2018; 8:85. [PMID: 29616196 PMCID: PMC5869912 DOI: 10.3389/fcimb.2018.00085] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 03/02/2018] [Indexed: 12/14/2022] Open
Abstract
Streptococcus suis serotype 2 is an important swine pathogen and an emerging zoonotic agent that causes severe infections. Recent studies have reported a eukaryotic-like Ser/Thr protein kinase (STK) gene and characterized its role in the growth and virulence of different S. suis 2 strains. In the present study, phosphoproteomic analysis was adopted to identify substrates of the STK protein. Seven proteins that were annotated to participate in different cell processes were identified as potential substrates, which suggests the pleiotropic effects of stk on S. suis 2 by targeting multiple pathways. Among them, a protein characterized as cell division initiation protein (DivIVA) was further investigated. In vitro analysis demonstrated that the recombinant STK protein directly phosphorylates threonine at amino acid position 199 (Thr-199) of DivIVA. This effect could be completely abolished by the T199A mutation. To determine the specific role of DivIVA in growth and division, a divIVA mutant was constructed. The ΔdivIVA strain exhibited impaired growth and division, including lower viability, enlarged cell mass, asymmetrical division caused by aberrant septum, and extremely weak pathogenicity in a mouse infection model. Collectively, our results reveal that STK regulates the cell growth and virulence of S. suis 2 by targeting substrates that are involved in different biological pathways. The inactivation of DivIVA leads to severe defects in cell division and strongly attenuates pathogenicity, thereby indicating its potential as a molecular drug target against S. suis.
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Affiliation(s)
- Hua Ni
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China.,School of Life Sciences, Nanjing Normal University, Nanjing, China.,The Key Laboratory of Ecology and Biological Resources in Yarkand Oasis at Colleges and Universities Under the Department of Education of Xinjiang Uygur Autonomous Region, Kashgar University, Kashgar, China
| | - Weiwei Fan
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China.,Department of Pharmacy, Changzhou Wujin People's Hospital, Changzhou, China
| | - Chaolong Li
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China.,School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Qianqian Wu
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China
| | - Hongfen Hou
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China.,School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Dan Hu
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China
| | - Feng Zheng
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China
| | - Xuhui Zhu
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China
| | - Changjun Wang
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China
| | - Xiangrong Cao
- School of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Zhu-Qing Shao
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Xiuzhen Pan
- Department of Microbiology, Hua Dong Research Institute for Medicine and Biotechnics, Nanjing, China.,School of Life Sciences, Nanjing Normal University, Nanjing, China
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12
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Technological advances for interrogating the human kinome. Biochem Soc Trans 2017; 45:65-77. [PMID: 28202660 DOI: 10.1042/bst20160163] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 10/20/2016] [Accepted: 10/25/2016] [Indexed: 12/12/2022]
Abstract
There is increasing appreciation among researchers and clinicians of the value of investigating biology and pathobiology at the level of cellular kinase (kinome) activity. Kinome analysis provides valuable opportunity to gain insights into complex biology (including disease pathology), identify biomarkers of critical phenotypes (including disease prognosis and evaluation of therapeutic efficacy), and identify targets for therapeutic intervention through kinase inhibitors. The growing interest in kinome analysis has fueled efforts to develop and optimize technologies that enable characterization of phosphorylation-mediated signaling events in a cost-effective, high-throughput manner. In this review, we highlight recent advances to the central technologies currently available for kinome profiling and offer our perspectives on the key challenges remaining to be addressed.
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13
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Hall CL, Lytle BL, Jensen D, Hoff JS, Peterson FC, Volkman BF, Kristich CJ. Structure and Dimerization of IreB, a Negative Regulator of Cephalosporin Resistance in Enterococcus faecalis. J Mol Biol 2017; 429:2324-2336. [PMID: 28551334 DOI: 10.1016/j.jmb.2017.05.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 05/05/2017] [Accepted: 05/18/2017] [Indexed: 11/30/2022]
Abstract
Enterococcus faecalis, a leading cause of hospital-acquired infections, exhibits intrinsic resistance to most cephalosporins, which are antibiotics in the beta-lactam family that target cell-wall biosynthesis. A comprehensive understanding of the underlying genetic and biochemical mechanisms of cephalosporin resistance in E. faecalis is lacking. We previously determined that a transmembrane serine/threonine kinase (IreK) and its cognate phosphatase (IreP) reciprocally regulate cephalosporin resistance in E. faecalis, dependent on the kinase activity of IreK. Other than IreK itself, thus far the only known substrate for reversible phosphorylation by IreK and IreP is IreB, a small protein of unknown function that is well conserved in low-GC Gram-positive bacteria. We previously showed that IreB acts as a negative regulator of cephalosporin resistance in E. faecalis. However, the biochemical mechanism by which IreB modulates cephalosporin resistance remains unknown. As a next step toward an understanding of the mechanism by which IreB regulates resistance, we initiated a structure-function study on IreB. The NMR solution structure of IreB was determined, revealing that IreB adopts a unique fold and forms a dimer in vitro. Dimerization of IreB was confirmed in vivo. Substitutions at the dimer interface impaired IreB function and stability in vivo, indicating that dimerization is functionally important for the biological activity of IreB. Hence, these studies provide new insights into the structure and function of a widely conserved protein of unknown function that is an important regulator of antimicrobial resistance in E. faecalis.
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Affiliation(s)
- Cherisse L Hall
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Betsy L Lytle
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Davin Jensen
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jessica S Hoff
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Francis C Peterson
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Christopher J Kristich
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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14
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Zhang C, Sun W, Tan M, Dong M, Liu W, Gao T, Li L, Xu Z, Zhou R. The Eukaryote-Like Serine/Threonine Kinase STK Regulates the Growth and Metabolism of Zoonotic Streptococcus suis. Front Cell Infect Microbiol 2017; 7:66. [PMID: 28326294 PMCID: PMC5339665 DOI: 10.3389/fcimb.2017.00066] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 02/21/2017] [Indexed: 12/21/2022] Open
Abstract
Like eukaryotes, bacteria express one or more serine/threonine kinases (STKs) that initiate diverse signaling networks. The STK from Streptococcus suis is encoded by a single-copy stk gene, which is crucial in stress response and virulence. To further understand the regulatory mechanism of STK in S. suis, a stk deletion strain (Δstk) and its complementary strain (CΔstk) were constructed to systematically decode STK characteristics by applying whole transcriptome RNA sequencing (RNA-Seq) and phosphoproteomic analysis. Numerous genes were differentially expressed in Δstk compared with the wild-type parental strain SC-19, including 320 up-regulated and 219 down-regulated genes. Particularly, 32 virulence-associated genes (VAGs) were significantly down-regulated in Δstk. Seven metabolic pathways relevant to bacterial central metabolism and translation are significantly repressed in Δstk. Phosphoproteomic analysis further identified 12 phosphoproteins that exhibit differential phosphorylation in Δstk. These proteins are associated with cell growth and division, glycolysis, and translation. Consistently, phenotypic assays confirmed that the Δstk strain displayed deficient growth and attenuated pathogenicity. Thus, STK is a central regulator that plays an important role in cell growth and division, as well as S. suis metabolism.
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Affiliation(s)
- Chunyan Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Wen Sun
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Meifang Tan
- Veterinary Medicine Laboratory, Institute of Animal Husbandry and Veterinary Medicine, Jiangxi Academy of Agricultural Sciences Nanchang, China
| | - Mengmeng Dong
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Wanquan Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Ting Gao
- Veterinary Medicine Laboratory, Institute of Animal Husbandry and Veterinary Science, Hubei Academy of Agricultural Sciences Wuhan, China
| | - Lu Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China; Cooperative Innovation Center of Sustainable Pig ProductionWuhan, China
| | - Zhuofei Xu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China; Cooperative Innovation Center of Sustainable Pig ProductionWuhan, China
| | - Rui Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural UniversityWuhan, China; Cooperative Innovation Center of Sustainable Pig ProductionWuhan, China
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15
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Sajid A, Arora G, Singhal A, Kalia VC, Singh Y. Protein Phosphatases of Pathogenic Bacteria: Role in Physiology and Virulence. Annu Rev Microbiol 2015; 69:527-47. [DOI: 10.1146/annurev-micro-020415-111342] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Andaleeb Sajid
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
| | - Gunjan Arora
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
| | - Anshika Singhal
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
| | - Vipin C. Kalia
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
| | - Yogendra Singh
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
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16
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Manuse S, Fleurie A, Zucchini L, Lesterlin C, Grangeasse C. Role of eukaryotic-like serine/threonine kinases in bacterial cell division and morphogenesis. FEMS Microbiol Rev 2015; 40:41-56. [DOI: 10.1093/femsre/fuv041] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2015] [Indexed: 11/14/2022] Open
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17
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Wright DP, Ulijasz AT. Regulation of transcription by eukaryotic-like serine-threonine kinases and phosphatases in Gram-positive bacterial pathogens. Virulence 2015; 5:863-85. [PMID: 25603430 PMCID: PMC4601284 DOI: 10.4161/21505594.2014.983404] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Bacterial eukaryotic-like serine threonine kinases (eSTKs) and serine threonine phosphatases (eSTPs) have emerged as important signaling elements that are indispensable for pathogenesis. Differing considerably from their histidine kinase counterparts, few eSTK genes are encoded within the average bacterial genome, and their targets are pleiotropic in nature instead of exclusive. The growing list of important eSTK/P substrates includes proteins involved in translation, cell division, peptidoglycan synthesis, antibiotic tolerance, resistance to innate immunity and control of virulence factors. Recently it has come to light that eSTK/Ps also directly modulate transcriptional machinery in many microbial pathogens. This novel form of regulation is now emerging as an additional means by which bacteria can alter their transcriptomes in response to host-specific environmental stimuli. Here we focus on the ability of eSTKs and eSTPs in Gram-positive bacterial pathogens to directly modulate transcription, the known mechanistic outcomes of these modifications, and their roles as an added layer of complexity in controlling targeted RNA synthesis to enhance virulence potential.
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Key Words
- OCS, one-component signaling
- PASTA, penicillin-binding protein and Ser/Thr kinase associated
- PPM, protein phosphatase metal binding
- PTM, posttranslational modification
- REC, receiver
- ROS, reactive oxygen species
- TCS, two-component signaling
- bacteria
- eSTK, eukaryotic-like serine-threonine kinase
- eSTP, eukaryotic-like serine-threonine phosphatase
- infection
- phosphorylation
- serine threonine kinase
- serine threonine phosphatase
- transcription
- wHTH, winged helix-turn-helix
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Affiliation(s)
- David P Wright
- a MRC Centre for Molecular Bacteriology and Infection (CMBI); Imperial College London ; London , UK
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18
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The sensor histidine kinase RgfC affects group B streptococcal virulence factor expression independent of its response regulator RgfA. Infect Immun 2015; 83:1078-88. [PMID: 25561709 DOI: 10.1128/iai.02738-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Group B streptococci (GBS; Streptococcus agalactiae) are beta-hemolytic, Gram-positive bacteria that are common asymptomatic colonizers of healthy adults. However, these opportunistic bacteria also cause invasive infections in human newborns and in certain adult populations. To adapt to the various environments encountered during its disease cycle, GBS encodes a number of two-component signaling systems. Previous studies have indicated that the TCS comprising the sensor histidine kinase RgfC and the response regulator RgfA mediate GBS binding to extracellular matrix components, such as fibrinogen. However, in certain GBS clinical isolates, a point mutation in rgfA results in premature truncation of the response regulator. The truncated RgfA protein lacks the C-terminal DNA binding domain necessary for promoter binding and gene regulation. Here, we show that deletion of rgfC in GBS strains lacking a functional RgfA increased systemic infection. Furthermore, infection with the rgfC mutant increased induction of proinflammatory signaling pathways in vivo. Phosphoproteomic analysis revealed that 19 phosphopeptides corresponding to 12 proteins were differentially phosphorylated at aspartate, cysteine, serine, threonine, or tyrosine residues in the rgfC mutant. This included aspartate phosphorylation of a tyrosine kinase, CpsD, and a transcriptional regulator. Consistent with this observation, microarray analysis of the rgfC mutant indicated that >200 genes showed altered expression compared to the isogenic wild-type strain and included transcriptional regulators, transporters, and genes previously associated with GBS pathogenesis. Our observations suggest that in the absence of RgfA, nonspecific RgfC signaling affects the expression of virulence factors and GBS pathogenesis.
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19
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IreB, a Ser/Thr kinase substrate, influences antimicrobial resistance in Enterococcus faecalis. Antimicrob Agents Chemother 2013; 57:6179-86. [PMID: 24080657 DOI: 10.1128/aac.01472-13] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enterococcus faecalis is a Gram-positive bacterium that is a major cause of hospital-acquired infections, in part due to its intrinsic resistance to cephalosporins. The mechanism that confers intrinsic cephalosporin resistance in enterococci remains incompletely defined. Previously, we have shown that the Ser/Thr protein kinase and phosphatase pair IreK and IreP act antagonistically to regulate cephalosporin resistance in E. faecalis. We hypothesize that IreK senses antibiotic-induced cell wall damage and activates a signaling pathway leading to antibiotic resistance. However, the factors downstream of IreK have not yet been identified. To discover such factors, suppressor mutations that restored resistance to a ΔireK kinase mutant were identified. Mutations were found in IreB, a highly conserved gene of unknown function that is widespread among low-GC Gram-positive bacteria. We show that IreB plays a negative regulatory role in cephalosporin resistance and is an endogenous substrate of both IreK and IreP. IreB is phosphorylated on conserved threonine residues, and mutations at these sites impair cephalosporin resistance. Our results are consistent with a model in which the activity of IreB is modulated by IreK-dependent phosphorylation in a signaling pathway required for cephalosporin resistance and begin to shed light on the function of this previously uncharacterized protein.
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20
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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: 114] [Impact Index Per Article: 10.4] [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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21
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Firon A, Tazi A, Da Cunha V, Brinster S, Sauvage E, Dramsi S, Golenbock DT, Glaser P, Poyart C, Trieu-Cuot P. The Abi-domain protein Abx1 interacts with the CovS histidine kinase to control virulence gene expression in group B Streptococcus. PLoS Pathog 2013; 9:e1003179. [PMID: 23436996 PMCID: PMC3578759 DOI: 10.1371/journal.ppat.1003179] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 12/19/2012] [Indexed: 12/20/2022] Open
Abstract
Group B Streptococcus (GBS), a common commensal of the female genital tract, is the leading cause of invasive infections in neonates. Expression of major GBS virulence factors, such as the hemolysin operon cyl, is regulated directly at the transcriptional level by the CovSR two-component system. Using a random genetic approach, we identified a multi-spanning transmembrane protein, Abx1, essential for the production of the GBS hemolysin. Despite its similarity to eukaryotic CaaX proteases, the Abx1 function is not involved in a post-translational modification of the GBS hemolysin. Instead, we demonstrate that Abx1 regulates transcription of several virulence genes, including those comprising the hemolysin operon, by a CovSR-dependent mechanism. By combining genetic analyses, transcriptome profiling, and site-directed mutagenesis, we showed that Abx1 is a regulator of the histidine kinase CovS. Overexpression of Abx1 is sufficient to activate virulence gene expression through CovS, overcoming the need for an additional signal. Conversely, the absence of Abx1 has the opposite effect on virulence gene expression consistent with CovS locked in a kinase-competent state. Using a bacterial two-hybrid system, direct interaction between Abx1 and CovS was mapped specifically to CovS domains involved in signal processing. We demonstrate that the CovSR two-component system is the core of a signaling pathway integrating the regulation of CovS by Abx1 in addition to the regulation of CovR by the serine/threonine kinase Stk1. In conclusion, our study reports a regulatory function for Abx1, a member of a large protein family with a characteristic Abi-domain, which forms a signaling complex with the histidine kinase CovS in GBS. The gram-positive Streptococcus genus includes three major human pathogens that are members of the normal microflora: Streptococcus pneumoniae (also known as the pneumococcus), Streptococcus pyogenes (Group A Streptococcus), and Streptococcus agalactiae (Group B Streptococcus). Their carriage in the population is highly dynamic and mostly asymptomatic. However, each of these species can cause a wide spectrum of diseases, from local infections to systemic and fatal infections including septicemia and meningitis. Expression of streptococcal virulence-associated genes is tightly regulated at the transcriptional level. However, the signal(s) and the precise molecular events controlling the switch from commensalism to virulence are not yet understood. In this study, we identified and characterized a bacterial protein essential for virulence gene expression in Group B Streptococcus, the main pathogen of neonates. We show that this transmembrane protein, named Abx1, interacts with the histidine kinase CovS to modulate the activity of the major regulator of virulence CovR. We define how a core set of four proteins, Abx1, CovS, CovR, and the serine/threonine kinase Stk1, interact to control the expression of virulence genes in S. agalactiae. We propose that Abx1-like proteins, that are widespread in bacteria, might be part of a conserved mechanism of two-component system regulation.
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Affiliation(s)
- Arnaud Firon
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, Paris, France.
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22
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Mijakovic I, Macek B. Impact of phosphoproteomics on studies of bacterial physiology. FEMS Microbiol Rev 2012; 36:877-92. [DOI: 10.1111/j.1574-6976.2011.00314.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 10/21/2011] [Accepted: 10/22/2011] [Indexed: 11/27/2022] Open
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23
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Control of cell division in Streptococcus pneumoniae by the conserved Ser/Thr protein kinase StkP. Proc Natl Acad Sci U S A 2012; 109:E905-13. [PMID: 22431591 DOI: 10.1073/pnas.1119172109] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
How the human pathogen Streptococcus pneumoniae coordinates cell-wall synthesis during growth and division to achieve its characteristic oval shape is poorly understood. The conserved eukaryotic-type Ser/Thr kinase of S. pneumoniae, StkP, previously was reported to phosphorylate the cell-division protein DivIVA. Consistent with a role in cell division, GFP-StkP and its cognate phosphatase, GFP-PhpP, both localize to the division site. StkP localization depends on its penicillin-binding protein and Ser/Thr-associated domains that likely sense uncross-linked peptidoglycan, because StkP and PhpP delocalize in the presence of antibiotics that target the latest stages of cell-wall biosynthesis and in cells that have stopped dividing. Time-lapse microscopy shows that StkP displays an intermediate timing of recruitment to midcell: StkP arrives shortly after FtsA but before DivIVA. Furthermore, StkP remains at midcell longer than FtsA, until division is complete. Cells mutated for stkP are perturbed in cell-wall synthesis and display elongated morphologies with multiple, often unconstricted, FtsA and DivIVA rings. The data show that StkP plays an important role in regulating cell-wall synthesis and controls correct septum progression and closure. Overall, our results indicate that StkP signals information about the cell-wall status to key cell-division proteins and in this way acts as a regulator of cell division.
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24
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Burnside K, Rajagopal L. Aspects of eukaryotic-like signaling in Gram-positive cocci: a focus on virulence. Future Microbiol 2011; 6:747-61. [PMID: 21797690 DOI: 10.2217/fmb.11.62] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Living organisms adapt to the dynamic external environment for their survival. Environmental adaptation in prokaryotes is thought to be primarily accomplished by signaling events mediated by two-component systems, consisting of histidine kinases and response regulators. However, eukaryotic-like serine/threonine kinases (STKs) have recently been described to regulate growth, antibiotic resistance and virulence of pathogenic bacteria. This article summarizes the role of STKs and their cognate phosphatases (STPs) in Gram-positive cocci that cause invasive infections in humans. Given that a large number of inhibitors to eukaryotic STKs are approved for use in humans, understanding how serine/threonine phosphorylation regulates virulence and antibiotic resistance will be beneficial for the development of novel therapeutic strategies against bacterial infections.
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Affiliation(s)
- Kellie Burnside
- Department of Pediatric Infectious Diseases, University of Washington & Seattle Children's Hospital Research Institute, 1900 Ninth Avenue, Seattle, WA 98101-1304, USA
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25
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Burnside K, Lembo A, Harrell MI, Gurney M, Xue L, BinhTran NT, Connelly JE, Jewell KA, Schmidt BZ, de Los Reyes M, Tao WA, Doran KS, Rajagopal L. Serine/threonine phosphatase Stp1 mediates post-transcriptional regulation of hemolysin, autolysis, and virulence of group B Streptococcus. J Biol Chem 2011; 286:44197-44210. [PMID: 22081606 DOI: 10.1074/jbc.m111.313486] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Elucidating how serine/threonine phosphatases regulate kinase function and bacterial virulence is critical for our ability to combat these infections. Group B streptococci (GBS) are β-hemolytic Gram-positive bacteria that cause invasive infections in humans. To adapt to environmental changes, GBS encodes signaling mechanisms comprising two component systems and eukaryotic-like enzymes. We have previously described the importance of the serine/threonine kinase Stk1 to GBS pathogenesis. However, how the presence or absence of the cognate serine/threonine phosphatase Stp1 affects Stk1 function and GBS virulence is not known. Here, we show that GBS deficient only in Stp1 expression are markedly reduced for their ability to cause systemic infections, exhibit decreased β-hemolysin/cytolysin activity, and show increased sensitivity to autolysis. Although transcription of genes important for β-hemolysin/cytolysin expression and export is similar to the wild type (WT), 294 genes (excluding stp1) showed altered expression in the stp1 mutant and included autolysin genes. Furthermore, phosphopeptide enrichment analysis identified that 35 serine/threonine phosphopeptides, corresponding to 27 proteins, were unique to the stp1 mutant. This included phosphorylation of ATP synthase, DNA and RNA helicases, and proteins important for cell division and protein synthesis. Collectively, our results indicate that Stp1 is important for appropriate regulation of Stk1 function, hemolysin activity, autolysis, and GBS virulence.
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Affiliation(s)
- Kellie Burnside
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Annalisa Lembo
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Maria Isabel Harrell
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Michael Gurney
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California 92182
| | - Liang Xue
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Nguyen-Thao BinhTran
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - James E Connelly
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Kelsea A Jewell
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Byron Z Schmidt
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Melissa de Los Reyes
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101
| | - Weiguo Andy Tao
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Kelly S Doran
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California 92182
| | - Lakshmi Rajagopal
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine and Seattle Children's Hospital Research Institute, Seattle, Washington 98101.
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26
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Abstract
Genomic studies have revealed the presence of Ser/Thr kinases and phosphatases in many bacterial species, although their physiological roles have largely been unclear. Here we review bacterial Ser/Thr kinases (eSTKs) that show homology in their catalytic domains to eukaryotic Ser/Thr kinases and their partner phosphatases (eSTPs) that are homologous to eukaryotic phosphatases. We first discuss insights into the enzymatic mechanism of eSTK activation derived from structural studies on both the ligand-binding and catalytic domains. We then turn our attention to the identified substrates of eSTKs and eSTPs for a number of species and to the implications of these findings for understanding their physiological roles in these organisms.
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Jani C, Eoh H, Lee JJ, Hamasha K, Sahana MB, Han JS, Nyayapathy S, Lee JY, Suh JW, Lee SH, Rehse SJ, Crick DC, Kang CM. Regulation of polar peptidoglycan biosynthesis by Wag31 phosphorylation in mycobacteria. BMC Microbiol 2010; 10:327. [PMID: 21190553 PMCID: PMC3019181 DOI: 10.1186/1471-2180-10-327] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 12/29/2010] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Sensing and responding to environmental changes is a central aspect of cell division regulation. Mycobacterium tuberculosis contains eleven Ser/Thr kinases, two of which, PknA and PknB, are key signaling molecules that regulate cell division/morphology. One substrate of these kinases is Wag31, and we previously showed that partial depletion of Wag31 caused morphological changes indicative of cell wall defects, and that the phosphorylation state of Wag31 affected cell growth in mycobacteria. In the present study, we further characterized the role of the Wag31 phosphorylation in polar peptidoglycan biosynthesis. RESULTS We demonstrate that the differential growth among cells expressing different wag31 alleles (wild-type, phosphoablative, or phosphomimetic) is caused by, at least in part, dissimilar nascent peptidoglycan biosynthesis. The phosphorylation state of Wag31 is found to be important for protein-protein interactions between the Wag31 molecules, and thus, for its polar localization. Consistent with these results, cells expressing a phosphomimetic wag31 allele have a higher enzymatic activity in the peptidoglycan biosynthetic pathway. CONCLUSIONS The Wag31Mtb phosphorylation is a novel molecular mechanism by which Wag31Mtb regulates peptidoglycan synthesis and thus, optimal growth in mycobacteria.
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Affiliation(s)
- Charul Jani
- Department of Biological Science, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
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Burnside K, Lembo A, de los Reyes M, Iliuk A, BinhTran NT, Connelly JE, Lin WJ, Schmidt BZ, Richardson AR, Fang FC, Tao WA, Rajagopal L. Regulation of hemolysin expression and virulence of Staphylococcus aureus by a serine/threonine kinase and phosphatase. PLoS One 2010; 5:e11071. [PMID: 20552019 PMCID: PMC2884019 DOI: 10.1371/journal.pone.0011071] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 05/14/2010] [Indexed: 02/02/2023] Open
Abstract
Exotoxins, including the hemolysins known as the alpha (α) and beta (β) toxins, play an important role in the pathogenesis of Staphylococcus aureus infections. A random transposon library was screened for S. aureus mutants exhibiting altered hemolysin expression compared to wild type. Transposon insertions in 72 genes resulting in increased or decreased hemolysin expression were identified. Mutations inactivating a putative cyclic di-GMP synthetase and a serine/threonine phosphatase (Stp1) were found to reduce hemolysin expression, and mutations in genes encoding a two component regulator PhoR, LysR family transcriptional regulator, purine biosynthetic enzymes and a serine/threonine kinase (Stk1) increased expression. Transcription of the hla gene encoding α toxin was decreased in a Δstp1 mutant strain and increased in a Δstk1 strain. Microarray analysis of a Δstk1 mutant revealed increased transcription of additional exotoxins. A Δstp1 strain is severely attenuated for virulence in mice and elicits less inflammation and IL-6 production than the Δstk1 strain. In vivo phosphopeptide enrichment and mass spectrometric analysis revealed that threonine phosphorylated peptides corresponding to Stk1, DNA binding histone like protein (HU), serine-aspartate rich fibrinogen/bone sialoprotein binding protein (SdrE) and a hypothetical protein (NWMN_1123) were present in the wild type and not in the Δstk1 mutant. Collectively, these studies suggest that Stk1 mediated phosphorylation of HU, SrdE and NWMN_1123 affects S. aureus gene expression and virulence.
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Affiliation(s)
- Kellie Burnside
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Annalisa Lembo
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Melissa de los Reyes
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Anton Iliuk
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Nguyen-Thao BinhTran
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - James E. Connelly
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Wan-Jung Lin
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Byron Z. Schmidt
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
| | - Anthony R. Richardson
- Departments of Laboratory Medicine and Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Ferric C. Fang
- Departments of Laboratory Medicine and Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Weiguo Andy Tao
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, United States of America
| | - Lakshmi Rajagopal
- Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, United States of America
- * E-mail:
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29
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Yang Q, Zhang M, Harrington DJ, Black GW, Sutcliffe IC. A proteomic investigation of Streptococcus agalactiae grown under conditions associated with neonatal exposure reveals the upregulation of the putative virulence factor C protein β antigen. Int J Med Microbiol 2010; 300:331-7. [DOI: 10.1016/j.ijmm.2010.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 11/30/2009] [Accepted: 01/06/2010] [Indexed: 12/14/2022] Open
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Giefing C, Jelencsics KE, Gelbmann D, Senn BM, Nagy E. The pneumococcal eukaryotic-type serine/threonine protein kinase StkP co-localizes with the cell division apparatus and interacts with FtsZ in vitro. Microbiology (Reading) 2010; 156:1697-1707. [DOI: 10.1099/mic.0.036335-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The importance of serine/threonine phosphorylation in signalling and regulation of gene expression in prokaryotes has been widely recognized. Driven by our interest in StkP (the pneumococcal serine/threonine kinase homologue) for vaccine development, we studied its cellular localization. We found that the C-terminally located PASTA (penicillin-binding protein and serine/threonine kinase associated) domains, but not the N-terminal kinase domain of StkP, were located on the surface of live pneumococcal cells grown in vitro and were also accessible to antibodies during pneumococcal infection in mice and man. Most importantly, we discovered, by immunofluorescence microscopy, that StkP co-localized with the cell division apparatus. StkP and FtsZ, the prokaryotic tubulin homologue, co-localized at mid-cell in most cells. Formation and constriction of the ring-like structure of StkP followed the dynamic changes of FtsZ in dividing cells. This pattern resembles that of the ‘late’ divisome protein penicillin-binding protein 2X. The lack of StkP in gene deletion mutants did not disturb FtsZ ring formation, further suggesting that StkP joins the divisome after the FtsZ ring is assembled. We also present evidence that StkP binds and phosphorylates recombinant FtsZ in vitro; however, we could not detect changes in the phosphorylation of FtsZ in a stkP deletion strain relative to wild-type cells. Based on its cell-division-dependent localization and interaction with FtsZ, we propose that StkP plays a currently undefined role in cell division of pneumococcus.
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Affiliation(s)
- Carmen Giefing
- Intercell AG, Vienna Biocenter 3, A-1030 Vienna, Austria
| | | | | | | | - Eszter Nagy
- Intercell AG, Vienna Biocenter 3, A-1030 Vienna, Austria
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31
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Lembo A, Gurney MA, Burnside K, Banerjee A, de los Reyes M, Connelly JE, Lin WJ, Jewell KA, Vo A, Renken CW, Doran KS, Rajagopal L. Regulation of CovR expression in Group B Streptococcus impacts blood-brain barrier penetration. Mol Microbiol 2010; 77:431-43. [PMID: 20497331 DOI: 10.1111/j.1365-2958.2010.07215.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Group B Streptococcus (GBS) is an important cause of invasive infections in humans. The pathogen encodes a number of virulence factors including the pluripotent beta-haemolysin/cytolysin (beta-H/C). As GBS has the disposition of both a commensal organism and an invasive pathogen, it is important for the organism to appropriately regulate beta-H/C and other virulence factors in response to the environment. GBS can repress transcription of beta-H/C using the two-component system, CovR/CovS. Recently, we described that the serine/threonine kinase Stk1 can phosphorylate CovR at threonine 65 to relieve repression of beta-H/C. In this study, we show that infection with CovR-deficient GBS strains resulted in increased sepsis. Although CovR-deficient GBS showed decreased ability to invade the brain endothelium in vitro, they were more proficient in induction of permeability and pro-inflammatory signalling pathways in brain endothelium and penetration of the blood-brain barrier (BBB) in vivo. Microarray analysis revealed that CovR positively regulates its own expression and regulates the expression of 153 genes. Collectively, our results suggest that the positive feedback loop which regulates CovR transcription modulates host cell interaction and immune defence and may facilitate the transition of GBS from a commensal organism to a virulent meningeal pathogen.
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Affiliation(s)
- Annalisa Lembo
- Department of Pediatric Infectious Diseases, University of Washington School of Medicine, Seattle, WA 98195, USA
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32
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Identification of multiple substrates of the StkP Ser/Thr protein kinase in Streptococcus pneumoniae. J Bacteriol 2010; 192:3629-38. [PMID: 20453092 DOI: 10.1128/jb.01564-09] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Monitoring the external environment and responding to its changes are essential for the survival of all living organisms. The transmission of extracellular signals in prokaryotes is mediated mainly by two-component systems. In addition, genomic analyses have revealed that many bacteria contain eukaryotic-type Ser/Thr protein kinases. The human pathogen Streptococcus pneumoniae encodes 13 two-component systems and has a single copy of a eukaryotic-like Ser/Thr protein kinase gene designated stkP. Previous studies demonstrated the pleiotropic role of the transmembrane protein kinase StkP in pneumococcal physiology. StkP regulates virulence, competence, and stress resistance and plays a role in the regulation of gene expression. To determine the intracellular signaling pathways controlled by StkP, we used a proteomic approach for identification of its substrates. We detected six proteins phosphorylated on threonine by StkP continuously during growth. We identified three new substrates of StkP: the Mn-dependent inorganic pyrophosphatase PpaC, the hypothetical protein spr0334, and the cell division protein DivIVA. Contrary to the results of a previous study, we did not confirm that the alpha-subunit of RNA polymerase is a target of StkP. We showed that StkP activation and substrate recognition depend on the presence of a peptidoglycan-binding domain comprising four extracellular penicillin-binding protein- and Ser/Thr kinase-associated domain (PASTA domain) repeats. We found that StkP is regulated in a growth-dependent manner and likely senses intracellular peptidoglycan subunits present in the cell division septa. In addition, stkP inactivation results in cell division defects. Thus, the data presented here suggest that StkP plays an important role in the regulation of cell division in pneumococcus.
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The Streptococcus mutans serine/threonine kinase, PknB, regulates competence development, bacteriocin production, and cell wall metabolism. Infect Immun 2010; 78:2209-20. [PMID: 20231406 DOI: 10.1128/iai.01167-09] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria can detect, transmit, and react to signals from the outside world by using two-component systems (TCS) and serine-threonine kinases and phosphatases. Streptococcus mutans contains one serine-threonine kinase, encoded by pknB. A gene encoding a serine-threonine phosphatase, pppL, is located upstream of pknB. In this study, the phenotypes of pknB and pppL single mutants and a pknB pppL double mutant were characterized. All mutants exhibited a reduction in genetic transformability and biofilm formation, showed abnormal cell shapes, grew slower than the wild-type strain in several complex media, and exhibited reduced acid tolerance. The mutants had reduced cariogenic capacity but no significant defects in colonization in a rat caries model. Whole-genome transcriptome analysis revealed that a pknB mutant showed reduced expression of genes involved in bacteriocin production and genetic competence. Among the genes that were differentially regulated in the pknB mutant, several were likely to be involved in cell wall metabolism. One such gene, SMU.2146c, and two genes encoding bacteriocins were shown to also be downregulated in a vicK mutant, which encodes a sensor kinase involved in the response to oxidative stress. Collectively, the results lead us to speculate that PknB may modulate the activity of the two-component signal transduction systems VicKR and ComDE. Real-time reverse transcriptase PCR (RT-PCR) showed that genes downregulated in the pknB mutant were upregulated in the pppL mutant, indicating that PppL serves to counteract PknB.
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34
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Shah IM, Dworkin J. Induction and regulation of a secreted peptidoglycan hydrolase by a membrane Ser/Thr kinase that detects muropeptides. Mol Microbiol 2010; 75:1232-43. [PMID: 20070526 DOI: 10.1111/j.1365-2958.2010.07046.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Here, we report that the model Gram-positive organism, Bacillus subtilis, expresses and secretes a muralytic enzyme, YocH, in response to cell wall-derived muropeptides derived from growing cells but not lysed cells. This induction is dependent on PrkC, a membrane Ser/Thr kinase that binds to peptidoglycan and that belongs to a broadly conserved family including the essential PknB kinase of M. tuberculosis. YocH stimulates its own expression in a PrkC-dependent manner demonstrating the presence of an autoregulatory loop during growth. Cells lacking YocH display a survival defect in stationary phase but enzymes secreted by other cells in the culture rescue this defect. The essential translation factor EF-G is an in vivo substrate of PrkC and this phosphorylation occurs in response to muropeptides. Therefore, we hypothesize that YocH is used by the bacterium to digest peptidoglycan released by other bacteria in the milieu and that the presence of these fragments is detected by a membrane kinase that modifies a key regulator of translation as well as to stimulate its own expression.
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Affiliation(s)
- Ishita M Shah
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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