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Gaur V, Bera S. Recent developments on UDP-N-acetylmuramoyl-L-alanine-D-gutamate ligase (Mur D) enzyme for antimicrobial drug development: An emphasis on in-silico approaches. CURRENT RESEARCH IN PHARMACOLOGY AND DRUG DISCOVERY 2022; 3:100137. [PMID: 36568273 PMCID: PMC9780078 DOI: 10.1016/j.crphar.2022.100137] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/09/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022] Open
Abstract
Introduction The rapid emergence of antibiotic resistance among various bacterial pathogens has been one of the major concerns of health organizations across the world. In this context, for the development of novel inhibitors against antibiotic-resistant bacterial pathogens, UDP-N-Acetylmuramoyl-L-Alanine-D-Glutamate Ligase (MurD) enzyme represents one of the most apposite targets. Body The present review focuses on updated advancements on MurD-targeted inhibitors in recent years along with genetic regulation, structural and functional characteristics of the MurD enzyme from various bacterial pathogens. A concise account of various crystal structures of MurD enzyme, submitted into Protein Data Bank is also discussed. Discussion MurD, an ATP dependent cytoplasmic enzyme is an important target for drug discovery. The genetic organization of MurD enzyme is well elucidated and many crystal structures of MurD enzyme are submitted into Protein Data bank. Various inhibitors against MurD enzyme have been developed so far with an increase in the use of in-silico methods in the recent past. But cell permeability barriers and conformational changes of MurD enzyme during catalytic reaction need to be addressed for effective drug development. So, a combination of in-silico methods along with experimental work is proposed to counter the catalytic machinery of MurD enzyme.
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Key Words
- Antibiotic resistance
- HTS, High Throughput Screening
- In-silico
- MD, Molecular Dynamics
- MIC, Minimum Inhibitory Concentration
- MurD
- PDB, Protein Data Bank
- PEP, Phosphoenolpyruvate
- PG, Peptidoglycan
- Peptidoglycan
- SAR, Structural Activity Relationship
- UDP-GlcNAc, UDP-N-acetylglucosamine
- UDP-Mpp, UDP-N-acetylmuramylpentapeptide
- UDP-MurNAc, UDP-N-acetylmuramicacid
- UMA, UDP N-acetylmuramoyl-l-alanine
- UNAG, UDP- N-acetylglucosamine
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Shinde Y, Ahmad I, Surana S, Patel H. The Mur Enzymes Chink in the Armour of Mycobacterium tuberculosis cell wall. Eur J Med Chem 2021; 222:113568. [PMID: 34118719 DOI: 10.1016/j.ejmech.2021.113568] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 02/02/2023]
Abstract
TUBERCULOSIS: (TB) transmitted by Mycobacterium tuberculosis (Mtb) is one of the top 10 causes of death globally. Currently, the widespread occurrence of resistance toward Mtb strains is becoming a significant concern to public health. This scenario exaggerated the need for the discovery of novel targets and their inhibitors. Targeting the "Mtb cell wall peptidoglycan synthesis" is an attractive strategy to overcome drug resistance. Mur enzymes (MurA-MurF) play essential roles in the peptidoglycan synthesis by catalyzing the ligation of key amino acid residues to the stem peptide. These enzymes are unique and confined to the eubacteria and are absent in humans, representing potential targets for anti-tubercular drug discovery. Mtb Mur ligases with the same catalytic mechanism share conserved amino acid regions and structural features that can conceivably exploit for the designing of the inhibitors, which can simultaneously target more than one isoforms (MurC-MurF) of the enzyme. In light of these findings in the current review, we have discussed the recent advances in medicinal chemistry of Mtb Mur enzymes (MurA-MurF) and their inhibitors, offering attractive multi-targeted strategies to combat the problem of drug-resistant in M. tuberculosis.
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Affiliation(s)
- Yashodeep Shinde
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, District Dhule, 425405, Maharashtra, India
| | - Iqrar Ahmad
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, District Dhule, 425405, Maharashtra, India
| | - Sanjay Surana
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, District Dhule, 425405, Maharashtra, India
| | - Harun Patel
- Department of Pharmaceutical Chemistry, R. C. Patel Institute of Pharmaceutical Education and Research, Shirpur, District Dhule, 425405, Maharashtra, India.
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Stokas H, Rhodes HL, Purdy GE. Modulation of the M. tuberculosis cell envelope between replicating and non-replicating persistent bacteria. Tuberculosis (Edinb) 2020; 125:102007. [PMID: 33035766 DOI: 10.1016/j.tube.2020.102007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/24/2020] [Accepted: 10/02/2020] [Indexed: 12/18/2022]
Abstract
The success of Mycobacterium tuberculosis as a human pathogen depends on the bacterium's ability to persist in a quiescent form in oxygen and nutrient-poor host environments. In vitro studies have demonstrated that these restricting environments induce a shift from bacterial replication to non-replicating persistence (NRP). Entry into NRP involves changes in bacterial metabolism and remodeling of the cell envelope. Findings consistent with the phenotypes observed in vitro have been observed in patient and animal model samples. This review focuses on the cell envelope differences seen between replicating and NRP M. tuberculosis and summarizes the ways in which serine/threonine protein kinases (STPKs) may mediate this process.
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Affiliation(s)
- Haley Stokas
- Oregon Health & Science University, Department of Molecular Microbiology & Immunology, Portland, OR, 97239, United States
| | - Heather L Rhodes
- Oregon Health & Science University, Department of Molecular Microbiology & Immunology, Portland, OR, 97239, United States
| | - Georgiana E Purdy
- Oregon Health & Science University, Department of Molecular Microbiology & Immunology, Portland, OR, 97239, United States.
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Kandasamy S, Palaniyandi K, Gupta UD, Narayanan S. Double deletion of PknI/DacB2 leads to attenuation of Mycobacterium tuberculosis for growth and virulence. Tuberculosis (Edinb) 2020; 123:101957. [PMID: 32741534 DOI: 10.1016/j.tube.2020.101957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 04/24/2020] [Accepted: 05/05/2020] [Indexed: 11/17/2022]
Abstract
Serine/Threonine Protein Kinases (STPKs) phosphorylates target proteins thereby regulates various important cellular signal transduction pathways such as cell division and cell wall synthesis. It has been demonstrated that the STPKs regulate peptidoglycan biosynthesis by phosphorylating penicillin binding proteins (PBPs). We extensively characterized both PknI (STPK) and DacB2 (PBP) roles individually as well as combining by genetic knockout and phenotypic characterization studies. In the present study, we analyzed the role of PknI and DacB2 in cell division and virulence. The double knockout (DKO) strain growth was reduced under stress conditions like acidic pH, nutrient depletion media and low oxygen availability conditions. We also found that the DKO growth was significantly reduced in macrophage cell line and it was hypersensitive to oxidative and nitrosative stress condition. The DKO strain significantly attenuated in guinea pig model which was measured by reduced bacillary load, gross pathological and histopathological damages. Overall, these results clearly demonstrated that both PknI and DacB2 together play an important role in cell division under stress conditions, the DKO strain significantly attenuated both in vitro and in vivo models.
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Affiliation(s)
- Srinivasan Kandasamy
- Department of Immunology, ICMR-National Institute for Research in Tuberculosis, Chennai, 600031, India
| | - Kannan Palaniyandi
- Department of Immunology, ICMR-National Institute for Research in Tuberculosis, Chennai, 600031, India
| | - Umesh Datta Gupta
- ICMR-National JALMA Institute for Leprosy and Other Mycobacterial Diseases, Agra, 282001, India
| | - Sujatha Narayanan
- Department of Immunology, ICMR-National Institute for Research in Tuberculosis, Chennai, 600031, India.
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Alsayed SSR, Beh CC, Foster NR, Payne AD, Yu Y, Gunosewoyo H. Kinase Targets for Mycolic Acid Biosynthesis in Mycobacterium tuberculosis. Curr Mol Pharmacol 2019; 12:27-49. [PMID: 30360731 DOI: 10.2174/1874467211666181025141114] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/11/2018] [Accepted: 10/11/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Mycolic acids (MAs) are the characteristic, integral building blocks for the mycomembrane belonging to the insidious bacterial pathogen Mycobacterium tuberculosis (M.tb). These C60-C90 long α-alkyl-β-hydroxylated fatty acids provide protection to the tubercle bacilli against the outside threats, thus allowing its survival, virulence and resistance to the current antibacterial agents. In the post-genomic era, progress has been made towards understanding the crucial enzymatic machineries involved in the biosynthesis of MAs in M.tb. However, gaps still remain in the exact role of the phosphorylation and dephosphorylation of regulatory mechanisms within these systems. To date, a total of 11 serine-threonine protein kinases (STPKs) are found in M.tb. Most enzymes implicated in the MAs synthesis were found to be phosphorylated in vitro and/or in vivo. For instance, phosphorylation of KasA, KasB, mtFabH, InhA, MabA, and FadD32 downregulated their enzymatic activity, while phosphorylation of VirS increased its enzymatic activity. These observations suggest that the kinases and phosphatases system could play a role in M.tb adaptive responses and survival mechanisms in the human host. As the mycobacterial STPKs do not share a high sequence homology to the human's, there have been some early drug discovery efforts towards developing potent and selective inhibitors. OBJECTIVE Recent updates to the kinases and phosphatases involved in the regulation of MAs biosynthesis will be presented in this mini-review, including their known small molecule inhibitors. CONCLUSION Mycobacterial kinases and phosphatases involved in the MAs regulation may serve as a useful avenue for antitubercular therapy.
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Affiliation(s)
- Shahinda S R Alsayed
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
| | - Chau C Beh
- Western Australia School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Bentley 6102 WA, Australia.,David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142, United States
| | - Neil R Foster
- Western Australia School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Bentley 6102 WA, Australia
| | - Alan D Payne
- School of Molecular and Life Sciences, Curtin University, Perth, WA 6102, Australia
| | - Yu Yu
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
| | - Hendra Gunosewoyo
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia
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Abstract
Actinobacteria is a group of diverse bacteria. Most species in this class of bacteria are filamentous aerobes found in soil, including the genus Streptomyces perhaps best known for their fascinating capabilities of producing antibiotics. These bacteria typically have a Gram-positive cell envelope, comprised of a plasma membrane and a thick peptidoglycan layer. However, there is a notable exception of the Corynebacteriales order, which has evolved a unique type of outer membrane likely as a consequence of convergent evolution. In this chapter, we will focus on the unique cell envelope of this order. This cell envelope features the peptidoglycan layer that is covalently modified by an additional layer of arabinogalactan . Furthermore, the arabinogalactan layer provides the platform for the covalent attachment of mycolic acids , some of the longest natural fatty acids that can contain ~100 carbon atoms per molecule. Mycolic acids are thought to be the main component of the outer membrane, which is composed of many additional lipids including trehalose dimycolate, also known as the cord factor. Importantly, a subset of bacteria in the Corynebacteriales order are pathogens of human and domestic animals, including Mycobacterium tuberculosis. The surface coat of these pathogens are the first point of contact with the host immune system, and we now know a number of host receptors specific to molecular patterns exposed on the pathogen's surface, highlighting the importance of understanding how the cell envelope of Actinobacteria is structured and constructed. This chapter describes the main structural and biosynthetic features of major components found in the actinobacterial cell envelopes and highlights the key differences between them.
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Affiliation(s)
- Kathryn C Rahlwes
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA
| | - Ian L Sparks
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, 639 North Pleasant Street, Amherst, MA, 01003, USA.
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Chaurasiya SK. Tuberculosis: Smart manipulation of a lethal host. Microbiol Immunol 2018; 62:361-379. [PMID: 29687912 DOI: 10.1111/1348-0421.12593] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/21/2018] [Accepted: 04/16/2018] [Indexed: 11/28/2022]
Abstract
Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a global threat to human health. Development of drug resistance and co-infection with HIV has increased the morbidity and mortality caused by TB. Macrophages serve as primary defense against microbial infections, including TB. Upon recognition and uptake of mycobacteria, macrophages initiate a series of events designed to lead to generation of effective immune responses and clearance of infection. However, pathogenic mycobacteria utilize multiple mechanisms for manipulating macrophage responses to protect itself from being killed and to survive within these cells that are designed to kill them. The outcomes of mycobacterial infection are determined by several host- and pathogen-related factors. Significant advancements in understanding mycobacterial pathogenesis have been made in recent years. In this review, some of the important factors/mechanisms regulating mycobacterial survival inside macrophages are discussed.
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Affiliation(s)
- Shivendra K Chaurasiya
- Host-pathogen Interaction and Signal Transduction Laboratory, Department of Microbiology, School of Biological Sciences, Dr. Hari Singh Gour University, Sagar, MP-470003, India
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Sun L, Zhang L, Wang T, Jiao W, Li Q, Yin Q, Li J, Qi H, Xu F, Shen C, Xiao J, Liu S, Mokrousov I, Huang H, Shen A. Mutations of Mycobacterium tuberculosis induced by anti-tuberculosis treatment result in metabolism changes and elevation of ethambutol resistance. INFECTION GENETICS AND EVOLUTION 2018; 72:151-158. [PMID: 30292007 DOI: 10.1016/j.meegid.2018.09.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 09/12/2018] [Accepted: 09/30/2018] [Indexed: 10/28/2022]
Abstract
Selective pressure from antibiotic use is one of the most important risk factors associated with the development of drug resistance in Mycobacterium tuberculosis (MTB). However, the mechanisms underlying drug resistance at the molecular level remain partly unclear. Therefore, the purpose of this study was to investigate the potential functional effect of novel mutations arising from anti-tuberculosis treatment. We analyzed two multidrug-resistant TB (MDR-TB) isolates from the same patient; one collected before and one almost a year after commencing MDR-TB treatment. The post-treatment isolate exhibited elevated ethambutol resistance. We sequenced the whole genomes of the two clinical isolates and detected six novel polymorphisms affecting the genes Rv1026, nc0021, Rv2155c, Rv2437, and Rv3696c, and the intergenic region between Rv2764c and Rv2765. Metabolomics approach was used to reveal the effect of the found variation on the metabolic pathways of MTB. Partial least squares-discriminant analysis showed a clear differentiation between the two isolates, involving a total of 175 metabolites. Pathway analysis showed that these metabolites are mainly involved in amino sugar and nucleotide sugar metabolism, β-alanine metabolism, sulfur metabolism, and galactose metabolism. The increased ethambutol resistance exhibited by the post-treatment MDR-TB strain could speculatively be linked to the identified genetic variations, which affected the synthesis of a number of metabolites associated with sources of carbon and energy. This may have been the main factor underlying the increased ethambutol resistance of this isolate.
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Affiliation(s)
- Lin Sun
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Liqun Zhang
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug-Resistant Tuberculosis Research, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China
| | - Ting Wang
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Weiwei Jiao
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Qinjing Li
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Qingqin Yin
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Jieqiong Li
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Hui Qi
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Fang Xu
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Chen Shen
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Jing Xiao
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Shuping Liu
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China
| | - Igor Mokrousov
- Laboratory of Molecular Epidemiology and Evolutionary Genetics, St Petersburg Pasteur Institute, St Petersburg, Russia.
| | - Hairong Huang
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug-Resistant Tuberculosis Research, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China.
| | - Adong Shen
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Key Discipline of Pediatrics (Capital Medical University), Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Clinical Research Center for Respiratory Diseases, National Center for Children's Health, Beijing, China.
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9
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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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10
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Khan MZ, Kaur P, Nandicoori VK. Targeting the messengers: Serine/threonine protein kinases as potential targets for antimycobacterial drug development. IUBMB Life 2018; 70:889-904. [DOI: 10.1002/iub.1871] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 04/22/2018] [Indexed: 02/03/2023]
Affiliation(s)
- Mehak Zahoor Khan
- National Institute of Immunology, Aruna Asaf Ali Marg; New Delhi India
| | - Prabhjot Kaur
- National Institute of Immunology, Aruna Asaf Ali Marg; New Delhi India
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11
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Puffal J, García-Heredia A, Rahlwes KC, Siegrist MS, Morita YS. Spatial control of cell envelope biosynthesis in mycobacteria. Pathog Dis 2018; 76:4953754. [DOI: 10.1093/femspd/fty027] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/25/2018] [Indexed: 11/12/2022] Open
Affiliation(s)
- Julia Puffal
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Alam García-Heredia
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Kathryn C Rahlwes
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - M Sloan Siegrist
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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12
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Arora D, Chawla Y, Malakar B, Singh A, Nandicoori VK. The transpeptidase PbpA and noncanonical transglycosylase RodA of Mycobacterium tuberculosis play important roles in regulating bacterial cell lengths. J Biol Chem 2018. [PMID: 29530985 DOI: 10.1074/jbc.m117.811190] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The cell wall of Mycobacterium tuberculosis (Mtb) is a complex structure that protects the pathogen in hostile environments. Peptidoglycan (PG), which helps determine the morphology of the cell envelope, undergoes substantial remodeling under stress. This meshwork of linear chains of sugars, cross-linked through attached peptides, is generated through the sequential action of enzymes termed transglycosylases and transpeptidases. The Mtb genome encodes two classical transglycosylases and four transpeptidases, the functions of which are not fully elucidated. Here, we present work on the yet uncharacterized transpeptidase PbpA and a nonclassical transglycosylase RodA. We elucidate their roles in regulating in vitro growth and in vivo survival of pathogenic mycobacteria. We find that RodA and PbpA are required for regulating cell length, but do not affect mycobacterial growth. Biochemical analyses show PbpA to be a classical transpeptidase, whereas RodA is identified to be a member of an emerging class of noncanonical transglycosylases. Phosphorylation of RodA at Thr-463 modulates its biological function. In a guinea pig infection model, RodA and PbpA are found to be required for both bacterial survival and formation of granuloma structures, thus underscoring the importance of these proteins in mediating mycobacterial virulence in the host. Our results emphasize the fact that whereas redundant enzymes probably compensate for the absence of RodA or PbpA during in vitro growth, the two proteins play critical roles for the survival of the pathogen inside its host.
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Affiliation(s)
- Divya Arora
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067 India and
| | - Yogesh Chawla
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067 India and
| | - Basanti Malakar
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067 India and
| | - Archana Singh
- CSIR-Institute of Genomics and Integrative Biology, 110025 New Delhi, India
| | - Vinay Kumar Nandicoori
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067 India and
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Eukaryotic-type serine/threonine kinase mediated phosphorylation at Thr 169 perturbs mycobacterial guanylate kinase activity. Biosci Rep 2017; 37:BSR20171048. [PMID: 28963370 PMCID: PMC5686395 DOI: 10.1042/bsr20171048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 09/23/2017] [Accepted: 09/25/2017] [Indexed: 01/22/2023] Open
Abstract
Guanylate kinase is an essential and conserved enzyme in nucleotide biosynthetic pathway that transfers phosphoryl group of ATP to GMP for yielding GDP. Here, we report the phosphorylation of guanylate kinase from Mycobacterium tuberculosis (mGmk) by eukaryotic-type Ser/Thr kinase, PknA. Mass spectrometric studies identified Thr101 and Thr169 as phosphorylatable residues in mGmk. To evaluate the significance of phosphorylation in these threonines, two point (T101A and T169A) and one double (T101A-T169A) mutants were generated. The kinase assay with these mutant proteins revealed the major contribution of Thr169 compared with Thr101 in the phosphorylation of mGmk. Kinetic analysis indicated that p-mGmk was deficient in its enzymatic activity compared with that of its un-phosphorylated counterpart. Surprisingly, its phosphoablated (T169A) as well as phosphomimic (T169E) variants exhibited decreased activity as was observed with p-mGmk. Structural analysis suggested that phosphorylation of Thr169 might affect its interaction with Arg166, which is crucial for the functioning of mGmk. In fact, the R166A and R166K mutant proteins displayed a drastic decrease in enzymatic activity compared with that of the wild-type mGmk. Molecular dynamics (MD) studies of mGmk revealed that upon phosphorylation of Thr169, the interactions of Arg165/Arg166 with Glu158, Asp121 and residues of the loop in GMP-binding domain are perturbed. Taken together, our results illuminate the mechanistic insights into phosphorylation-mediated modulation of the catalytic activity of mGmk.
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Malhotra N, Karthikeyan S, Chakraborti PK. Phosphorylation of mycobacterial phosphodiesterase by eukaryotic-type Ser/Thr kinase controls its two distinct and mutually exclusive functionalities. J Biol Chem 2017; 292:17362-17374. [PMID: 28855253 DOI: 10.1074/jbc.m117.784124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 08/03/2017] [Indexed: 02/05/2023] Open
Abstract
Phosphorylation-mediated negative feedback regulation of cAMP levels by phosphodiesterase is well-established in eukaryotic cells. However, such a mechanism remains unexplored in prokaryotes. We report here the involvement of eukaryotic-type Ser/Thr kinases, particularly PknA in trans-phosphorylating phosphodiesterase from Mycobacterium tuberculosis (mPDE), that resulted in decreased enzyme turnover rate compared with its unphosphorylated counterpart. To elucidate the role of mPDE phosphorylation in hydrolyzing cellular cAMP, we utilized a phosphodiesterase knock-out Escherichia coli strain, ΔcpdA, where interference of endogenous eukaryotic-type Ser/Thr kinases could be excluded. Interestingly, the mPDE-complemented ΔcpdA strain showed enhanced cAMP levels in the presence of PknA, and this effect was antagonized by PknA-K42N, a kinase-dead variant. Structural analysis of mPDE revealed that four Ser/Thr residues (Ser-20, Thr-22, Thr-182, and Thr-240) were close to the active site, indicating their possible role in phosphorylation-mediated alteration in enzymatic activity. Mutation of these residues one at a time to alanine or a combination of all four (mPDE-4A) affected catalytic activity of mPDE. Moreover, mPDE-4A protein in kinase assays exhibited reduction in its phosphorylation compared with mPDE. In consonance, phosphoproteins obtained after co-expression of PknA with mPDE/S20A/T240A/4A displayed decreased phospho-signal intensities in immunoblotting with anti-phosphoserine/phosphothreonine antibodies. Furthermore, unlike mPDE, phospho-ablated mPDE-T309A protein exhibited impaired cell wall localization in Mycobacterium smegmatis, whereas mPDE-4A behaved similarly as wild type. Taken together, our findings establish mutually exclusive dual functionality of mPDE upon PknA-mediated phosphorylation, where Ser-20/Thr-240 influence enzyme activity and Thr-309 endorses its cell wall localization.
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Affiliation(s)
- Neha Malhotra
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160 036, India
| | - Subramanian Karthikeyan
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160 036, India
| | - Pradip K Chakraborti
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160 036, India
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Abstract
Reversible protein phosphorylation is the most common type of epigenetic posttranslational modification in living cells used as a major regulation mechanism of biological processes. The Mycobacterium tuberculosis genome encodes for 11 serine/threonine protein kinases that are responsible for sensing environmental signals to coordinate a cellular response to ensure the pathogen's infectivity, survival, and growth. To overcome killing mechanisms generated within the host during infection, M. tuberculosis enters a state of nonreplicating persistence that is characterized by arrested growth, limited metabolic activity, and phenotypic resistance to antimycobacterial drugs. In this article we focus our attention on the role of M. tuberculosis serine/threonine protein kinases in sensing the host environment to coordinate the bacilli's physiology, including growth, cell wall components, and central metabolism, to establish a persistent infection.
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Yadav GS, Ravala SK, Malhotra N, Chakraborti PK. Phosphorylation Modulates Catalytic Activity of Mycobacterial Sirtuins. Front Microbiol 2016; 7:677. [PMID: 27242704 PMCID: PMC4860497 DOI: 10.3389/fmicb.2016.00677] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/26/2016] [Indexed: 11/20/2022] Open
Abstract
Sirtuins are NAD+-dependent deacetylases involved in the regulation of diverse cellular processes and are conserved throughout phylogeny. Here we report about in vitro transphosphorylation of the only NAD+-dependent deacetylase (mDAC) present in the genome of Mycobacterium tuberculosis by eukaryotic-type Ser/Thr kinases, particularly PknA. The phosphorylated mDAC displayed decreased deacetylase activity compared to its unphosphorylated counterpart. Mass-spectrometric study identified seven phosphosites in mDAC; however, mutational analysis highlighted major contribution of Thr-214 for phosphorylation of the protein. In concordance to this observation, variants of mDAC substituting Thr-214 with either Ala (phospho-ablated) or Glu (phosphomimic) exhibited significantly reduced deacetylase activity suggesting phosphorylation mediated control of enzymatic activity. To assess the role of phosphorylation towards functionality of mDAC, we opted for a sirtuin knock-out strain of Escherichia coli (Δdac), where interference of endogenous mycobacterial kinases could be excluded. The Δdac strain in nutrient deprived acetate medium exhibited compromised growth and complementation with mDAC reversed this phenotype. The phospho-ablated or phosphomimic variant, on the other hand, was unable to restore the functionality of mDAC indicating the role of phosphorylation per se in the process. We further over-expressed mDAC or mDAC-T214A as His-tagged protein in M. smegmatis, where endogenous eukaryotic-type Ser/Thr kinases are present. Anti-phosphothreonine antibody recognized both mDAC and mDAC-T214A proteins in western blotting. However, the extent of phosphorylation as adjudged by scanning the band intensity, was significantly low in the mutant protein (mDAC-T214A) compared to that of the wild-type (mDAC). Furthermore, expression of PknA in the mDAC complemented Δdac strain was able to phosphorylate M. tuberculosis sirtuin. The growth profile of this culture in acetate medium was slow compared to that transformed with only vector. On the other hand, use of a kinase dead variant, PknA-K42N instead of PknA, did not display such behavior, which again supported phosphorylation mediated control of mDAC protein. Thus, our results ostensibly render evidence for cross-talk between two distinct post-translational modifications, phosphorylation and deacetylation, in any bacteria. Bioinformatic analysis further indicated conservation of Thr-214 among different mDAC orthologs, thereby arguing the event as mycobacteria specific.
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Affiliation(s)
| | | | - Neha Malhotra
- CSIR-Institute of Microbial Technology Chandigarh, India
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Malhotra N, Chakraborti PK. Eukaryotic-Type Ser/Thr Protein Kinase Mediated Phosphorylation of Mycobacterial Phosphodiesterase Affects its Localization to the Cell Wall. Front Microbiol 2016; 7:123. [PMID: 26904001 PMCID: PMC4746578 DOI: 10.3389/fmicb.2016.00123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/22/2016] [Indexed: 11/13/2022] Open
Abstract
Phosphodiesterase enzymes, involved in cAMP hydrolysis reaction, are present throughout phylogeny and their phosphorylation mediated regulation remains elusive in prokaryotes. In this context, we focused on this enzyme from Mycobacterium tuberculosis. The gene encoded by Rv0805 was PCR amplified and expressed as a histidine-tagged protein (mPDE) utilizing Escherichia coli based expression system. In kinase assays, upon incubation with mycobacterial Clade I eukaryotic-type Ser/Thr kinases (PknA, PknB, and PknL), Ni-NTA purified mPDE protein exhibited transphosphorylation ability albeit with varying degree. When mPDE was co-expressed one at a time with these kinases in E. coli, it was also recognized by an anti-phosphothreonine antibody, which further indicates its phosphorylating ability. Mass spectrometric analysis identified Thr-309 of mPDE as a phosphosite. In concordance with this observation, anti-phosphothreonine antibody marginally recognized mPDE-T309A mutant protein; however, such alteration did not affect the enzymatic activity. Interestingly, mPDE expressed in Mycobacterium smegmatis yielded a phosphorylated protein that preferentially localized to cell wall. In contrast, mPDE-T309A, the phosphoablative variant of mPDE, did not show such behavior. On the other hand, phosphomimics of mPDE (T309D or T309E), exhibited similar cell wall anchorage as was observed with the wild-type. Thus, our results provide credence to the fact that eukaryotic-type Ser/Thr kinase mediated phosphorylation of mPDE renders negative charge to the protein, promoting its localization on cell wall. Furthermore, multiple sequence alignment revealed that Thr-309 is conserved among mPDE orthologs of M. tuberculosis complex, which presumably emphasizes evolutionary significance of phosphorylation at this residue.
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Affiliation(s)
- Neha Malhotra
- CSIR-Institute of Microbial Technology Chandigarh, India
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Genetic features of Mycobacterium tuberculosis modern Beijing sublineage. Emerg Microbes Infect 2016; 5:e14. [PMID: 26905026 PMCID: PMC4777927 DOI: 10.1038/emi.2016.14] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/24/2015] [Accepted: 11/30/2015] [Indexed: 12/24/2022]
Abstract
Mycobacterium tuberculosis (MTB) Beijing strains have caused a great concern because of their rapid emergence and increasing prevalence in worldwide regions. Great efforts have been made to investigate the pathogenic characteristics of Beijing strains such as hypervirulence, drug resistance and favoring transmission. Phylogenetically, MTB Beijing family was divided into modern and ancient sublineages. Modern Beijing strains displayed enhanced virulence and higher prevalence when compared with ancient Beijing strains, but the genetic basis for this difference remains unclear. In this study, by analyzing previously published sequencing data of 1082 MTB Beijing isolates, we determined the genetic changes that were commonly present in modern Beijing strains but absent in ancient Beijing strains. These changes include 44 single-nucleotide polymorphisms (SNPs) and two short genomic deletions. Through bioinformatics analysis, we demonstrated that these genetic changes had high probability of functional effects. For example, 4 genes were frameshifted due to premature stop mutation or genomic deletions, 19 nonsynonymous SNPs located in conservative codons, and there is a significant enrichment in regulatory network for all nonsynonymous mutations. Besides, three SNPs located in promoter regions were verified to alter downstream gene expressions. Our study precisely defined the genetic features of modern Beijing strains and provided interesting clues for future researches to elucidate the mechanisms that underlie this sublineage's successful expansion. These findings from the analysis of the modern Beijing sublineage could provide us a model to understand the dynamics of pathogenicity of MTB.
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Abstract
The Mycobacterium tuberculosis genome encodes 11 serine/threonine protein kinases (STPKs). A similar number of two-component systems are also present, indicating that these two signal transduction mechanisms are both important in the adaptation of this bacterial pathogen to its environment. The M. tuberculosis phosphoproteome includes hundreds of Ser- and Thr-phosphorylated proteins that participate in all aspects of M. tuberculosis biology, supporting a critical role for the STPKs in regulating M. tuberculosis physiology. Nine of the STPKs are receptor type kinases, with an extracytoplasmic sensor domain and an intracellular kinase domain, indicating that these kinases transduce external signals. Two other STPKs are cytoplasmic and have regulatory domains that sense changes within the cell. Structural analysis of some of the STPKs has led to advances in our understanding of the mechanisms by which these STPKs are activated and regulated. Functional analysis has provided insights into the effects of phosphorylation on the activity of several proteins, but for most phosphoproteins the role of phosphorylation in regulating function is unknown. Major future challenges include characterizing the functional effects of phosphorylation for this large number of phosphoproteins, identifying the cognate STPKs for these phosphoproteins, and determining the signals that the STPKs sense. Ultimately, combining these STPK-regulated processes into larger, integrated regulatory networks will provide deeper insight into M. tuberculosis adaptive mechanisms that contribute to tuberculosis pathogenesis. Finally, the STPKs offer attractive targets for inhibitor development that may lead to new therapies for drug-susceptible and drug-resistant tuberculosis.
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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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Ladwig N, Franz-Wachtel M, Hezel F, Soufi B, Macek B, Wohlleben W, Muth G. Control of Morphological Differentiation of Streptomyces coelicolor A3(2) by Phosphorylation of MreC and PBP2. PLoS One 2015; 10:e0125425. [PMID: 25927987 PMCID: PMC4416010 DOI: 10.1371/journal.pone.0125425] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 03/23/2015] [Indexed: 12/14/2022] Open
Abstract
During morphological differentiation of Streptomyces coelicolor A3(2), the sporogenic aerial hyphae are transformed into a chain of more than fifty spores in a highly coordinated manner. Synthesis of the thickened spore envelope is directed by the Streptomyces spore wall synthesizing complex SSSC which resembles the elongasome of rod-shaped bacteria. The SSSC includes the eukaryotic type serine/threonine protein kinase (eSTPK) PkaI, encoded within a cluster of five independently transcribed eSTPK genes (SCO4775-4779). To understand the role of PkaI in spore wall synthesis, we screened a S. coelicolor genomic library for PkaI interaction partners by bacterial two-hybrid analyses and identified several proteins with a documented role in sporulation. We inactivated pkaI and deleted the complete SCO4775-4779 cluster. Deletion of pkaI alone delayed sporulation and produced some aberrant spores. The five-fold mutant NLΔ4775-4779 had a more severe defect and produced 18% aberrant spores affected in the integrity of the spore envelope. Moreover, overbalancing phosphorylation activity by expressing a second copy of any of these kinases caused a similar defect. Following co-expression of pkaI with either mreC or pbp2 in E. coli, phosphorylation of MreC and PBP2 was demonstrated and multiple phosphosites were identified by LC-MS/MS. Our data suggest that elaborate protein phosphorylation controls activity of the SSSC to ensure proper sporulation by suppressing premature cross-wall synthesis.
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Affiliation(s)
- Nils Ladwig
- Interfakultaeres Institut für Mikrobiologie und Infektionsmedizin Tuebingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universitaet Tuebingen, Auf der Morgenstelle 28, 72076 Tuebingen, Germany
| | - Mirita Franz-Wachtel
- Proteome Center Tuebingen, Interfakultaeres Institut für Zellbiologie, Eberhard Karls Universitaet Tuebingen, Auf der Morgenstelle 15,72076 Tübingen, Germany
| | - Felix Hezel
- Interfakultaeres Institut für Mikrobiologie und Infektionsmedizin Tuebingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universitaet Tuebingen, Auf der Morgenstelle 28, 72076 Tuebingen, Germany
| | - Boumediene Soufi
- Proteome Center Tuebingen, Interfakultaeres Institut für Zellbiologie, Eberhard Karls Universitaet Tuebingen, Auf der Morgenstelle 15,72076 Tübingen, Germany
| | - Boris Macek
- Proteome Center Tuebingen, Interfakultaeres Institut für Zellbiologie, Eberhard Karls Universitaet Tuebingen, Auf der Morgenstelle 15,72076 Tübingen, Germany
| | - Wolfgang Wohlleben
- Interfakultaeres Institut für Mikrobiologie und Infektionsmedizin Tuebingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universitaet Tuebingen, Auf der Morgenstelle 28, 72076 Tuebingen, Germany
| | - Günther Muth
- Interfakultaeres Institut für Mikrobiologie und Infektionsmedizin Tuebingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universitaet Tuebingen, Auf der Morgenstelle 28, 72076 Tuebingen, Germany
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22
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Kandasamy S, Narayanan S. Phenotypic characterization of a novel double knockout PknI/DacB2 from Mycobacterium tuberculosis. Microbiol Res 2015; 170:255-62. [DOI: 10.1016/j.micres.2014.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 09/24/2014] [Accepted: 10/17/2014] [Indexed: 11/30/2022]
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23
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Kouidmi I, Levesque RC, Paradis-Bleau C. The biology of Mur ligases as an antibacterial target. Mol Microbiol 2014; 94:242-53. [DOI: 10.1111/mmi.12758] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2014] [Indexed: 01/19/2023]
Affiliation(s)
- Imène Kouidmi
- Department of Microbiology, Infectiology and Immunology; Université de Montreal; Montreal Quebec Canada
| | - Roger C. Levesque
- Institut de biologie intégrative et des systèmes; Université Laval; Montreal Quebec Canada
| | - Catherine Paradis-Bleau
- Department of Microbiology, Infectiology and Immunology; Université de Montreal; Montreal Quebec Canada
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24
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Phosphorylation regulates mycobacterial proteasome. J Microbiol 2014; 52:743-54. [PMID: 25224505 DOI: 10.1007/s12275-014-4416-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 07/22/2014] [Accepted: 07/23/2014] [Indexed: 12/31/2022]
Abstract
Mycobacterium tuberculosis possesses a proteasome system that is required for the microbe to resist elimination by the host immune system. Despite the importance of the proteasome in the pathogenesis of tuberculosis, the molecular mechanisms by which proteasome activity is controlled remain largely unknown. Here, we demonstrate that the α-subunit (PrcA) of the M. tuberculosis proteasome is phosphorylated by the PknB kinase at three threonine residues (T84, T202, and T178) in a sequential manner. Furthermore, the proteasome with phosphorylated PrcA enhances the degradation of Ino1, a known proteasomal substrate, suggesting that PknB regulates the proteolytic activity of the proteasome. Previous studies showed that depletion of the proteasome and the proteasome-associated proteins decreases resistance to reactive nitrogen intermediates (RNIs) but increases resistance to hydrogen peroxide (H2O2). Here we show that PknA phosphorylation of unprocessed proteasome β-subunit (pre-PrcB) and α-subunit reduces the assembly of the proteasome complex and thereby enhances the mycobacterial resistance to H2O2 and that H2O2 stress diminishes the formation of the proteasome complex in a PknA-dependent manner. These findings indicate that phosphorylation of the M. tuberculosis proteasome not only modulates proteolytic activity of the proteasome, but also affects the proteasome complex formation contributing to the survival of M. tuberculosis under oxidative stress conditions.
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25
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Jayachandran R, BoseDasgupta S, Pieters J. Surviving the macrophage: tools and tricks employed by Mycobacterium tuberculosis. Curr Top Microbiol Immunol 2014; 374:189-209. [PMID: 23154833 DOI: 10.1007/82_2012_273] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Mycobacterium tuberculosis has evolved to withstand one of the most inhospitable cells within the human body, namely the macrophage, a cell that is normally geared toward the destruction of any invading microbe. How M. tuberculosis achieves this is still incompletely understood; however, a number of mechanisms are now known that provide advantages to M. tuberculosis for its survival and proliferation inside the macrophage. While some of these mechanisms are mediated by factors released by M. tuberculosis, others rely on host components that are being hijacked to benefit survival of M. tuberculosis within the macrophage as well to avoid the generation of an effective immune response. Here, we describe several of these mechanisms, also pointing out the potential usage of this knowledge toward the development of novel strategies to treat tuberculosis. Furthermore, we attempt to put the 'macrophage niche' into context with other intracellular pathogens and discuss some of the generalities as well as specializations that M. tuberculosis employs to survive.
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Affiliation(s)
- Rajesh Jayachandran
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056, Basel, Switzerland
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26
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Ruggiero A, De Simone P, Smaldone G, Squeglia F, Berisio R. Bacterial cell division regulation by Ser/Thr kinases: a structural perspective. Curr Protein Pept Sci 2013; 13:756-66. [PMID: 23305362 PMCID: PMC3601408 DOI: 10.2174/138920312804871201] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/16/2012] [Accepted: 08/03/2012] [Indexed: 12/17/2022]
Abstract
Recent genetic, biochemical and structural studies have established that eukaryotic-like Ser/Thr protein-kinases are critical mediators of developmental changes and host pathogen interactions in bacteria. Although with lower abundance compared to their homologues from eukaryotes, Ser/Thr protein-kinases are widespread in gram-positive bacteria. These data underline a key role of reversible Ser/Thr phosphorylation in bacterial physiology and virulence. Numerous studies have revealed how phosphorylation/dephosphorylation of Ser/Thr protein-kinases governs cell division and cell wall biosynthesis and that Ser/Thr protein kinases are responsible for distinct phenotypes, dependent on different environmental signals. In this review we discuss the current understandings of Ser/Thr protein-kinases functional processes based on structural data.
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Affiliation(s)
- Alessia Ruggiero
- Institute of Biostructure and Bioimaging, CNR, Via Mezzocannone, 16. I-80134, Napoli, Italy.
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27
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Jayachandran R, Scherr N, Pieters J. Elimination of intracellularly residing Mycobacterium tuberculosis through targeting of host and bacterial signaling mechanisms. Expert Rev Anti Infect Ther 2013; 10:1007-22. [PMID: 23106276 DOI: 10.1586/eri.12.95] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
With more than 2 billion latently infected people, TB continues to represent a serious threat to human health. According to the WHO, 1.1 million people died from TB in 2010, which is equal to approximately 3000 deaths per day. The causative agent of the disease, Mycobacterium tuberculosis, is a highly successful pathogen having evolved remarkable strategies to persist within the host. Although normally, upon phagocytosis by macrophages, bacteria are readily eliminated by lysosomes, pathogenic mycobacteria actively prevent destruction within macrophages. The strategies that pathogenic mycobacteria apply range from releasing virulence factors to manipulating host molecules resulting in the modulation of host signal transduction pathways in order to sustain their viability within the infected host. Here, we analyze the current status of how a better understanding of both the bacterial and host factors involved in virulence can be used to develop drugs that may be helpful to curb the TB epidemic.
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Affiliation(s)
- Rajesh Jayachandran
- Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
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Munshi T, Gupta A, Evangelopoulos D, Guzman JD, Gibbons S, Keep NH, Bhakta S. Characterisation of ATP-dependent Mur ligases involved in the biogenesis of cell wall peptidoglycan in Mycobacterium tuberculosis. PLoS One 2013; 8:e60143. [PMID: 23555903 PMCID: PMC3605390 DOI: 10.1371/journal.pone.0060143] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 02/21/2013] [Indexed: 11/30/2022] Open
Abstract
ATP-dependent Mur ligases (Mur synthetases) play essential roles in the biosynthesis of cell wall peptidoglycan (PG) as they catalyze the ligation of key amino acid residues to the stem peptide at the expense of ATP hydrolysis, thus representing potential targets for antibacterial drug discovery. In this study we characterized the division/cell wall (dcw) operon and identified a promoter driving the co-transcription of mur synthetases along with key cell division genes such as ftsQ and ftsW. Furthermore, we have extended our previous investigations of MurE to MurC, MurD and MurF synthetases from Mycobacterium tuberculosis. Functional analyses of the pure recombinant enzymes revealed that the presence of divalent cations is an absolute requirement for their activities. We also observed that higher concentrations of ATP and UDP-sugar substrates were inhibitory for the activities of all Mur synthetases suggesting stringent control of the cytoplasmic steps of the peptidoglycan biosynthetic pathway. In line with the previous findings on the regulation of mycobacterial MurD and corynebacterial MurC synthetases via phosphorylation, we found that all of the Mur synthetases interacted with the Ser/Thr protein kinases, PknA and PknB. In addition, we critically analyzed the interaction network of all of the Mur synthetases with proteins involved in cell division and cell wall PG biosynthesis to re-evaluate the importance of these key enzymes as novel therapeutic targets in anti-tubercular drug discovery.
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Affiliation(s)
- Tulika Munshi
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, London, United Kingdom
| | - Antima Gupta
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, London, United Kingdom
| | - Dimitrios Evangelopoulos
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, London, United Kingdom
| | - Juan David Guzman
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, London, United Kingdom
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, London, United Kingdom
| | - Simon Gibbons
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, London, United Kingdom
| | - Nicholas H. Keep
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, London, United Kingdom
| | - Sanjib Bhakta
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, London, United Kingdom
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29
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Falk SP, Weisblum B. Phosphorylation of the Streptococcus pneumoniae cell wall biosynthesis enzyme MurC by a eukaryotic-like Ser/Thr kinase. FEMS Microbiol Lett 2013; 340:19-23. [PMID: 23278311 DOI: 10.1111/1574-6968.12067] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 12/01/2022] Open
Abstract
Streptococcus pneumoniae contains a single Ser/Thr kinase-phosphatase pair known as StkP-PhpP. Here, we report the interaction of StkP-PhpP with S. pneumoniae UDP-N-acetylmuramoyl:L-alanine ligase, MurC, an enzyme that synthesizes an essential intermediate of the cell wall peptidoglycan pathway. Combinatorial phage display using StkP as target selected the peptide sequence YEVCGSDTVGC as an interacting partner and subsequently confirmed by ELISA. The phage peptide sequence YEVCGSDTVGC aligns closely with the MurC motif spanning S. pneumoniae amino acid coordinates 31-37. We show that MurC is phosphorylated by StkP and that phosphoMurC is dephosphorylated by PhpP. These data suggest a link between StkP-PhpP with the coordinated regulation of cell wall biosynthesis via MurC.
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Affiliation(s)
- Shaun P Falk
- Department of Medicine, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI 53706, USA
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Forrellad MA, Klepp LI, Gioffré A, Sabio y García J, Morbidoni HR, de la Paz Santangelo M, Cataldi AA, Bigi F. Virulence factors of the Mycobacterium tuberculosis complex. Virulence 2012; 4:3-66. [PMID: 23076359 PMCID: PMC3544749 DOI: 10.4161/viru.22329] [Citation(s) in RCA: 379] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Mycobacterium tuberculosis complex (MTBC) consists of closely related species that cause tuberculosis in both humans and animals. This illness, still today, remains to be one of the leading causes of morbidity and mortality throughout the world. The mycobacteria enter the host by air, and, once in the lungs, are phagocytated by macrophages. This may lead to the rapid elimination of the bacillus or to the triggering of an active tuberculosis infection. A large number of different virulence factors have evolved in MTBC members as a response to the host immune reaction. The aim of this review is to describe the bacterial genes/proteins that are essential for the virulence of MTBC species, and that have been demonstrated in an in vivo model of infection. Knowledge of MTBC virulence factors is essential for the development of new vaccines and drugs to help manage the disease toward an increasingly more tuberculosis-free world.
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Takahata Y, Inoue M, Kim K, Iio Y, Miyamoto M, Masui R, Ishihama Y, Kuramitsu S. Close proximity of phosphorylation sites to ligand in the phosphoproteome of the extreme thermophile Thermus thermophilus
HB8. Proteomics 2012; 12:1414-30. [DOI: 10.1002/pmic.201100573] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Yoshio Takahata
- Graduate School of Frontier Biosciences; Osaka University; Osaka Japan
| | - Masao Inoue
- Department of Biological Sciences; Graduate School of Science; Osaka University; Osaka Japan
| | - Kwang Kim
- Department of Biological Sciences; Graduate School of Science; Osaka University; Osaka Japan
| | - Yota Iio
- Department of Biological Sciences; Graduate School of Science; Osaka University; Osaka Japan
| | - Masaaki Miyamoto
- Radio Isotope Division; Center for Supports to Research and Education Activities; Department of Biology; Graduate School of Science; Kobe University; Kobe Japan
| | - Ryoji Masui
- Department of Biological Sciences; Graduate School of Science; Osaka University; Osaka Japan
- RIKEN SPring-8 Center; 1-1-1 Kouto Sayo-cho, Sayo-gun Hyogo Japan
| | - Yasushi Ishihama
- Institute for Advanced Biosciences; Keio University; Yamagata Japan
- Graduate School of Pharmaceutical Sciences; Kyoto University; Kyoto Japan
| | - Seiki Kuramitsu
- Graduate School of Frontier Biosciences; Osaka University; Osaka Japan
- Department of Biological Sciences; Graduate School of Science; Osaka University; Osaka Japan
- RIKEN SPring-8 Center; 1-1-1 Kouto Sayo-cho, Sayo-gun Hyogo Japan
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Cytoskeletal proteins of actinobacteria. Int J Cell Biol 2012; 2012:905832. [PMID: 22481946 PMCID: PMC3296230 DOI: 10.1155/2012/905832] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 10/06/2011] [Accepted: 10/23/2011] [Indexed: 11/19/2022] Open
Abstract
Although bacteria are considered the simplest life forms, we are now slowly unraveling their cellular complexity. Surprisingly, not only do bacterial cells have a cytoskeleton but also the building blocks are not very different from the cytoskeleton that our own cells use to grow and divide. Nonetheless, despite important advances in our understanding of the basic physiology of certain bacterial models, little is known about Actinobacteria, an ancient group of Eubacteria. Here we review current knowledge on the cytoskeletal elements required for bacterial cell growth and cell division, focusing on actinobacterial genera such as Mycobacterium, Corynebacterium, and Streptomyces. These include some of the deadliest pathogens on earth but also some of the most prolific producers of antibiotics and antitumorals.
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MurAA is required for intrinsic cephalosporin resistance of Enterococcus faecalis. Antimicrob Agents Chemother 2012; 56:2443-51. [PMID: 22290954 DOI: 10.1128/aac.05984-11] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enterococcus faecalis is a low-GC Gram-positive bacterium that is intrinsically resistant to cephalosporins, antibiotics that target cell wall biosynthesis. To probe the mechanistic basis for intrinsic resistance, a library of transposon mutants was screened to identify E. faecalis strains that are highly susceptible to ceftriaxone, revealing a transposon mutant with a disruption in murAA. murAA is predicted to encode a UDP-N-acetylglucosamine 1-carboxyvinyl transferase that catalyzes the first committed step in peptidoglycan synthesis: phosphoenolpyruvate (PEP)-dependent conversion of UDP-N-acetylglucosamine to UDP-N-acetylglucosamine-enolpyruvate. In-frame deletion of murAA, but not its homolog in the E. faecalis genome (murAB), led to increased susceptibility of E. faecalis to cephalosporins. Furthermore, expression of murAA enhanced cephalosporin resistance in an E. faecalis mutant lacking IreK (formerly PrkC), a key kinase required for cephalosporin resistance. Further genetic analysis revealed that MurAA catalytic activity is necessary but not sufficient for this role. Collectively, our data indicate that MurAA and MurAB have distinct roles in E. faecalis physiology and suggest that MurAA possesses a unique property or activity that enables it to enhance intrinsic resistance of E. faecalis to cephalosporins.
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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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Brown PJB, Kysela DT, Brun YV. Polarity and the diversity of growth mechanisms in bacteria. Semin Cell Dev Biol 2011; 22:790-8. [PMID: 21736947 DOI: 10.1016/j.semcdb.2011.06.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 06/12/2011] [Accepted: 06/17/2011] [Indexed: 11/20/2022]
Abstract
Bacterial cell growth is a complex process consisting of two distinct phases: cell elongation and septum formation prior to cell division. Although bacteria have evolved several different mechanisms for cell growth, it is clear that tight spatial and temporal regulation of peptidoglycan synthesis is a common theme. In this review, we discuss bacterial cell growth with a particular emphasis on bacteria that utilize tip extension as a mechanism for cell elongation. We describe polar growth among diverse bacteria and consider the advantages and consequences of this mode of cell elongation.
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Affiliation(s)
- Pamela J B Brown
- Department of Biology, Indiana University, Bloomington, IN 47405, United States
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Mutations in the regulatory network underlie the recent clonal expansion of a dominant subclone of the Mycobacterium tuberculosis Beijing genotype. INFECTION GENETICS AND EVOLUTION 2011; 11:587-97. [PMID: 21277396 DOI: 10.1016/j.meegid.2011.01.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 12/10/2010] [Accepted: 01/13/2011] [Indexed: 11/20/2022]
Abstract
The Beijing genotype family is an epidemiologically important sub-group of Mycobacterium tuberculosis. It has been suggested that the high frequency of the Beijing isolates in some areas could be explained by selective advantages. Some evidence suggests that the emerging and most frequently isolated "Typical Beijing" lineage has the ability to circumvent BCG-induced immunity. To investigate the phylogeny of the Beijing genotype of M. tuberculosis, the genome of six Beijing strains from three different countries was sequenced with next-generation sequencing. The phylogeny of these strains was established using single nucleotide polymorphisms (SNPs). The three Typical Beijing strains clustered very tightly in the Beijing phylogeny suggesting that Typical Beijing strains represent a monophyletic lineage and resulted from recent diversification. Typing of 150 M. tuberculosis strains with a subset of the SNPs and comparison of the IS6110 restriction-fragment length polymorphism (RFLP) patterns of these strains to a database of 1522 Beijing RFLP patterns revealed that about 80% of all Beijing strains belong to the Typical Beijing subclone, which indicates clonal expansion. To identify the genomic changes that are characteristic for all Typical Beijing strains and to reconstruct their most recent common ancestor, the presence of SNPs was assayed in other Beijing strains. We identified 51 SNPs that define the minimal set of polymorphisms for all Typical Beijing strains. Nonsynonymous polymorphisms in genes coding for the regulatory network were over-represented in this set of mutations. We suggest that alterations in the response to environmental signals may have enabled Typical Beijing strains to develop the emerging phenotype.
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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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Molle V, Kremer L. Division and cell envelope regulation by Ser/Thr phosphorylation: Mycobacterium shows the way. Mol Microbiol 2010; 75:1064-77. [PMID: 20487298 DOI: 10.1111/j.1365-2958.2009.07041.x] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mycobacterium tuberculosis (M. tb) has a complex lifestyle in different environments and involving several developmental stages. The success of M. tb results from its remarkable capacity to survive within the infected host, where it can persist in a non-replicating state for several decades. The survival strategies developed by M. tb are linked to the presence of an unusual cell envelope. However, little is known regarding its capacity to modulate and adapt production of cell wall components in response to environmental conditions or to changes in cell shape and cell division. Signal sensing leading to cellular responses must be tightly regulated to allow survival under variable conditions. Although prokaryotes generally control their signal transduction processes through two-component systems, signalling through Ser/Thr phosphorylation has recently emerged as a critical regulatory mechanism in bacteria. The genome of M. tb possesses a large family of eukaryotic-like Ser/Thr protein kinases (STPKs). The physiological roles of several mycobacterial STPK substrates are connected to cell shape/division and cell envelope biosynthesis. Although these regulatory mechanisms have mostly been studied in Mycobacterium, Ser/Thr phosphorylation appears also to regulate cell division and peptidoglycan synthesis in Corynebacterium and Streptomyces. This review focuses on the proteins which have been identified as STPK substrates and involved in the synthesis of major cell envelope components and cell shape/division in actinomycetes. It is also intended to describe how phosphorylation affects the activity of peptidoglycan biosynthetic enzymes or cell division proteins.
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Affiliation(s)
- Virginie Molle
- Institut de Biologie et Chimie des Protéines (IBCP UMR 5086), CNRS, Université Lyon1, IFR128 BioSciences, Lyon-Gerland, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
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40
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Malhotra V, Arteaga-Cortés LT, Clay G, Clark-Curtiss JE. Mycobacterium tuberculosis protein kinase K confers survival advantage during early infection in mice and regulates growth in culture and during persistent infection: implications for immune modulation. MICROBIOLOGY-SGM 2010; 156:2829-2841. [PMID: 20522497 PMCID: PMC3068690 DOI: 10.1099/mic.0.040675-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mycobacterium tuberculosis serine/threonine protein kinases (STPKs) are key regulators of growth and metabolism; however, evidence for their roles in virulence is limited. In a preliminary screen based on comparative expression between strains H37Rv and H37Ra, six STPK genes, pknD, pknG, pknH, pknJ, pknK and pknL, showed higher expression in H37Rv. In the second screen, STPK expression was analysed in H37Rv-infected human macrophages. Interestingly, significant expression of pknK was detected only at 18 h post-infection, suggesting its involvement in early infection events. We have investigated the roles of PknK in vitro and in vivo. PknK levels were induced under stationary phase and deletion of pknK resulted in increased resistance of the mutant to acidic pH, hypoxia, oxidative and stationary-phase stresses in vitro. These results, together with the increased survival of the ΔpknK strain during persistent infection in mice, reveal a role for PknK in adaptive mechanisms that slow the growth of mycobacteria. A novel finding of this study was the inhibition of growth of ΔpknK strain during acute infection in mice that correlated with the significant upregulation of tumour necrosis factor as well as the simultaneous downregulation of interleukin-12p40, interferon-γ and induced nitric oxide synthase transcripts. Finally, we provide evidence for the localization of PknK during infection and discuss its implications in pathogenesis.
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Affiliation(s)
- Vandana Malhotra
- Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ 85287, USA
| | - Lourdes T Arteaga-Cortés
- Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ 85287, USA
| | - Gwendolyn Clay
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Josephine E Clark-Curtiss
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA.,Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, AZ 85287, USA
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41
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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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42
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Jang J, Stella A, Boudou F, Levillain F, Darthuy E, Vaubourgeix J, Wang C, Bardou F, Puzo G, Gilleron M, Burlet-Schiltz O, Monsarrat B, Brodin P, Gicquel B, Neyrolles O. Functional characterization of the Mycobacterium tuberculosis serine/threonine kinase PknJ. MICROBIOLOGY-SGM 2010; 156:1619-1631. [PMID: 20185505 DOI: 10.1099/mic.0.038133-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Eukaryotic-like Ser/Thr protein kinases (STPKs) are present in many bacterial species, where they control various physiological and virulence processes by enabling microbial adaptation to specific environmental signals. PknJ is the only member of the 11 STPKs identified in Mycobacterium tuberculosis that still awaits characterization. Here we report that PknJ is a functional kinase that forms dimers in vitro, and contains a single transmembrane domain. Using a high-density peptide-chip-based technology, multiple potential mycobacterial targets were identified for PknJ. We confirmed PknJ-dependent phosphorylation of four of these targets: PknJ itself, which autophosphorylates at Thr(168), Thr(171) and Thr(173) residues; the transcriptional regulator EmbR; the methyltransferase MmaA4/Hma involved in mycolic acid biosynthesis; and the dipeptidase PepE, whose encoding gene is located next to pknJ in the mycobacterial genome. Our results provide a number of candidate phospho-targets for PknJ and possibly other mycobacterial STPKs that could be studied to investigate the role of STPKs in M. tuberculosis physiology and virulence.
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Affiliation(s)
- Jichan Jang
- Inserm Equipe Avenir Biology of Intracellular Pathogens, Institut Pasteur Korea, Seoul, Republic of Korea.,Unit of Mycobacterial Genetics, Institut Pasteur, Paris, France
| | - Alexandre Stella
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Frédéric Boudou
- Unit of Mycobacterial Genetics, Institut Pasteur, Paris, France
| | - Florence Levillain
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Eliette Darthuy
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Julien Vaubourgeix
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Chongzhen Wang
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Fabienne Bardou
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Germain Puzo
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Martine Gilleron
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Odile Burlet-Schiltz
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Bernard Monsarrat
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France
| | - Priscille Brodin
- Inserm Equipe Avenir Biology of Intracellular Pathogens, Institut Pasteur Korea, Seoul, Republic of Korea
| | | | - Olivier Neyrolles
- Université de Toulouse, Université Paul Sabatier, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Centre National de la Recherche Scientifique, Institut de Pharmacologie et de Biologie Structurale, F-31077 Toulouse, France.,Unit of Mycobacterial Genetics, Institut Pasteur, Paris, France
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Veyron-Churlet R, Zanella-Cléon I, Cohen-Gonsaud M, Molle V, Kremer L. Phosphorylation of the Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein reductase MabA regulates mycolic acid biosynthesis. J Biol Chem 2010; 285:12714-25. [PMID: 20178986 DOI: 10.1074/jbc.m110.105189] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mycolic acids are key cell wall components for the survival, pathogenicity, and antibiotic resistance of the human tubercle bacillus. Although it was thought that Mycobacterium tuberculosis tightly regulates their production to adapt to prevailing environmental conditions, the molecular mechanisms governing mycolic acid biosynthesis remained extremely obscure. Meromycolic acids, the direct precursors of mycolic acids, are synthesized by a type II fatty acid synthase from acyl carrier protein-bound substrates that are extended iteratively, with a reductive cycle in each round of extension, the second step of which is catalyzed by the essential beta-ketoacyl-acyl carrier protein reductase, MabA. In this study, we investigated whether post-translational modifications of MabA might represent a strategy employed by M. tuberculosis to regulate mycolic acid biosynthesis. Indeed, we show here that MabA was efficiently phosphorylated in vitro by several M. tuberculosis Ser/Thr protein kinases, including PknB, as well as in vivo in mycobacteria. Mass spectrometric analyses using LC-ESI/MS/MS and site-directed mutagenesis identified three phosphothreonines, with Thr(191) being the primary phosphor-acceptor. A MabA_T191D mutant, designed to mimic constitutive phosphorylation, exhibited markedly decreased ketoacyl reductase activity compared with the wild-type protein, as well as impaired binding of the NADPH cofactor, as demonstrated by fluorescence spectroscopy. The hypothesis that phosphorylation of Thr(191) alters the enzymatic activity of MabA, and subsequently mycolic acid biosynthesis, was further supported by the fact that constitutive overexpression of the mabA_T191D allele in Mycobacterium bovis BCG strongly impaired mycobacterial growth. Importantly, conditional expression of the phosphomimetic MabA_T191D led to a significant inhibition of de novo biosynthesis of mycolic acids. This study provides the first information on the molecular mechanism(s) involved in mycolic acid regulation through Ser/Thr protein kinase-dependent phosphorylation of a type II fatty acid synthase enzyme.
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Affiliation(s)
- Romain Veyron-Churlet
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier I, CNRS, UMR 5235, case 107, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
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Sureka K, Hossain T, Mukherjee P, Chatterjee P, Datta P, Kundu M, Basu J. Novel role of phosphorylation-dependent interaction between FtsZ and FipA in mycobacterial cell division. PLoS One 2010; 5:e8590. [PMID: 20066037 PMCID: PMC2797604 DOI: 10.1371/journal.pone.0008590] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 12/09/2009] [Indexed: 11/26/2022] Open
Abstract
The bacterial divisome is a multiprotein complex. Specific protein-protein interactions specify whether cell division occurs optimally, or whether division is arrested. Little is known about these protein-protein interactions and their regulation in mycobacteria. We have investigated the interrelationship between the products of the Mycobacterium tuberculosis gene cluster Rv0014c-Rv0019c, namely PknA (encoded by Rv0014c) and FtsZ-interacting protein A, FipA (encoded by Rv0019c) and the products of the division cell wall (dcw) cluster, namely FtsZ and FtsQ. M. smegmatis strains depleted in components of the two gene clusters have been complemented with orthologs of the respective genes of M. tuberculosis. Here we identify FipA as an interacting partner of FtsZ and FtsQ and establish that PknA-dependent phosphorylation of FipA on T77 and FtsZ on T343 is required for cell division under oxidative stress. A fipA knockout strain of M. smegmatis is less capable of withstanding oxidative stress than the wild type and showed elongation of cells due to a defect in septum formation. Localization of FtsQ, FtsZ and FipA at mid-cell was also compromised. Growth and survival defects under oxidative stress could be functionally complemented by fipA of M. tuberculosis but not its T77A mutant. Merodiploid strains of M. smegmatis expressing the FtsZ(T343A) showed inhibition of FtsZ-FipA interaction and Z ring formation under oxidative stress. Knockdown of FipA led to elongation of M. tuberculosis cells grown in macrophages and reduced intramacrophage growth. These data reveal a novel role of phosphorylation-dependent protein-protein interactions involving FipA, in the sustenance of mycobacterial cell division under oxidative stress.
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Affiliation(s)
| | | | | | | | - Pratik Datta
- Department of Chemistry, Bose Institute, Kolkata, India
| | | | - Joyoti Basu
- Department of Chemistry, Bose Institute, Kolkata, India
- * E-mail:
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Chao J, Wong D, Zheng X, Poirier V, Bach H, Hmama Z, Av-Gay Y. Protein kinase and phosphatase signaling in Mycobacterium tuberculosis physiology and pathogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1804:620-7. [PMID: 19766738 DOI: 10.1016/j.bbapap.2009.09.008] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 09/06/2009] [Accepted: 09/10/2009] [Indexed: 01/22/2023]
Abstract
Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis (TB), evades the antimicrobial defenses of the host and survives within the infected individual through a complex set of strategies. These include active prevention of host cellular killing processes as well as overwhelming adaptive gene expression. In the past decade, we have gained an increased understanding of how mycobacteria not only have the ability to adapt to a changing host environment but also actively interfere with the signaling machinery within the host cell to counteract or inhibit parts of the killing apparatus employed by the macrophage. Mtb is able to sense its environment via a set of phospho-signaling proteins which mediate its response and interaction with the host in a coordinated manner. In this review, we summarize the current knowledge about selected Mtb serine, threonine, and tyrosine kinase and phosphatase signaling proteins, focusing on the protein kinases, PknG and PtkA, and the protein phosphatase, PtpA.
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Affiliation(s)
- Joseph Chao
- Department of Microbiology, University of British Columbia, Vancouver, British Columbia, Canada V5Z 3J5
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Tiwari D, Singh RK, Goswami K, Verma SK, Prakash B, Nandicoori VK. Key residues in Mycobacterium tuberculosis protein kinase G play a role in regulating kinase activity and survival in the host. J Biol Chem 2009; 284:27467-79. [PMID: 19638631 DOI: 10.1074/jbc.m109.036095] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase G (PknG) in Mycobacterium tuberculosis has been shown to modulate phagosome-lysosome fusion. The protein has three distinct domains, an N-terminal Trx domain, a kinase domain, and a C-terminal TPR domain. The present study extensively analyzes the roles of these domains in regulating PknG kinase activity and function. We find that the kinase domain of PknG by itself is inactive, signifying the importance of the flanking domains. Although the deletion of the Trx domain severely impacts the activity of the protein, the C-terminal region also contributes significantly in regulating the activity of the kinase. Apart from this, PknG kinase activity is dependent on the presence of threonine 309 in the p + 1 loop of the activation segment. Mutating the conserved cysteine residues in the Trx motifs makes PknG refractory to changes in the redox environment. In vitro experiments identify threonine 63 as the major phosphorylation site of the protein. Importantly, we find that this is the only site in the protein that is phosphorylated in vivo. Macrophage infection studies reveal that the first 73 residues, the Trx motifs, and the threonine 63 residue are independently essential for modulating PknG-mediated survival of mycobacteria in its host. We have extended these studies to investigate the role of PknG and PknG mutants in the pathogenesis of mycobacteria in mice. Our results reinforce the findings from the macrophage infection experiments, and for the first time demonstrate that the expression of PknG in non-pathogenic mycobacteria allows the continued existence of these bacteria in host tissues.
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Affiliation(s)
- Divya Tiwari
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
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Kumar P, Kumar D, Parikh A, Rananaware D, Gupta M, Singh Y, Nandicoori VK. The Mycobacterium tuberculosis protein kinase K modulates activation of transcription from the promoter of mycobacterial monooxygenase operon through phosphorylation of the transcriptional regulator VirS. J Biol Chem 2009; 284:11090-9. [PMID: 19251699 DOI: 10.1074/jbc.m808705200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mycobacterium tuberculosis encodes for 11 eukaryotic-like serine/threonine protein kinases. Genetic and biochemical studies show that these kinases regulate various cellular processes including cell shape and morphology, glucose and glutamine transport, phagosome-lysosome fusion and the expression, and/or activity of transcription factors. PknK is the largest predicted serine/threonine protein kinase in M. tuberculosis. Here, we have cloned, overexpressed, and purified protein kinase K (PknK) to near homogeneity and show that its ability to phosphorylate proteins is dependent on the invariant lysine (Lys(55)), and on two conserved threonine residues present in its activation loop. Despite being devoid of any apparent transmembrane domain, PknK is localized to the cell wall fraction, suggesting probable anchoring of the kinase to the cell membrane region. The pknK gene is located in the vicinity of the virS gene, which is known to regulate the expression of the mycobacterial monooxygenase (mymA) operon. We report here for the first time that VirS is in fact a substrate of PknK. In addition, four of the proteins encoded by mymA operon are also found to be substrates of PknK. Results show that VirS is a bona fide substrate of PknK in vivo, and PknK-mediated phosphorylation of VirS increases its affinity for mym promoter DNA. Reporter assays reveal that PknK modulates VirS-mediated stimulation of transcription from the mym promoter. These findings suggest that the expression of mymA operon genes is regulated through PknK-mediated phosphorylation of VirS.
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Affiliation(s)
- Pawan Kumar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India
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48
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Fiuza M, Canova MJ, Patin D, Letek M, Zanella-Cléon I, Becchi M, Mateos LM, Mengin-Lecreulx D, Molle V, Gil JA. The MurC ligase essential for peptidoglycan biosynthesis is regulated by the serine/threonine protein kinase PknA in Corynebacterium glutamicum. J Biol Chem 2008; 283:36553-63. [PMID: 18974047 DOI: 10.1074/jbc.m807175200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Mur ligases play an essential role in the biosynthesis of bacterial cell-wall peptidoglycan and thus represent attractive targets for the design of novel antibacterials. These enzymes catalyze the stepwise formation of the peptide moiety of the peptidoglycan disaccharide peptide monomer unit. MurC is responsible of the addition of the first residue (L-alanine) onto the nucleotide precursor UDP-MurNAc. Phosphorylation of proteins by Ser/Thr protein kinases has recently emerged as a major physiological mechanism of regulation in prokaryotes. Herein, the hypothesis of a phosphorylation-dependent mechanism of regulation of the MurC activity was investigated in Corynebacterium glutamicum. We showed that MurC was phosphorylated in vitro by the PknA protein kinase. An analysis of the phosphoamino acid content indicated that phosphorylation exclusively occurred on threonine residues. Six phosphoacceptor residues were identified by mass spectrometry analysis, and we confirmed that mutagenesis to alanine residues totally abolished PknA-dependent phosphorylation of MurC. In vitro and in vivo ligase activity assays showed that the catalytic activity of MurC was impaired following mutation of these threonine residues. Further in vitro assays revealed that the activity of the MurC-phosphorylated isoform was severely decreased compared with the non-phosphorylated protein. To our knowledge, this is the first demonstration of a MurC ligase phosphorylation in vitro. The finding that phosphorylation is correlated with a decrease in MurC enzymatic activity could have significant consequences in the regulation of peptidoglycan biosynthesis.
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Affiliation(s)
- Maria Fiuza
- Departamento de Biología Molecular, Area de Microbiología, Facultad de Biología, Universidad de León, León 24071, Spain
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