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Keshavam CC, Naz S, Gupta A, Sanyal P, Kochar M, Gangwal A, Sangwan N, Kumar N, Tyagi E, Goel S, Singh NK, Sowpati DT, Khare G, Ganguli M, Raze D, Locht C, Basu-Modak S, Gupta M, Nandicoori VK, Singh Y. The heparin-binding hemagglutinin protein of Mycobacterium tuberculosis is a nucleoid-associated protein. J Biol Chem 2023; 299:105364. [PMID: 37865319 PMCID: PMC10665949 DOI: 10.1016/j.jbc.2023.105364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/05/2023] [Accepted: 10/10/2023] [Indexed: 10/23/2023] Open
Abstract
Nucleoid-associated proteins (NAPs) regulate multiple cellular processes such as gene expression, virulence, and dormancy throughout bacterial species. NAPs help in the survival and adaptation of Mycobacterium tuberculosis (Mtb) within the host. Fourteen NAPs have been identified in Escherichia coli; however, only seven NAPs are documented in Mtb. Given its complex lifestyle, it is reasonable to assume that Mtb would encode for more NAPs. Using bioinformatics tools and biochemical experiments, we have identified the heparin-binding hemagglutinin (HbhA) protein of Mtb as a novel sequence-independent DNA-binding protein which has previously been characterized as an adhesion molecule required for extrapulmonary dissemination. Deleting the carboxy-terminal domain of HbhA resulted in a complete loss of its DNA-binding activity. Atomic force microscopy showed HbhA-mediated architectural modulations in the DNA, which may play a regulatory role in transcription and genome organization. Our results showed that HbhA colocalizes with the nucleoid region of Mtb. Transcriptomics analyses of a hbhA KO strain revealed that it regulates the expression of ∼36% of total and ∼29% of essential genes. Deletion of hbhA resulted in the upregulation of ∼73% of all differentially expressed genes, belonging to multiple pathways suggesting it to be a global repressor. The results show that HbhA is a nonessential NAP regulating gene expression globally and acting as a plausible transcriptional repressor.
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Affiliation(s)
| | - Saba Naz
- Department of Zoology, University of Delhi, Delhi, India; CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Aanchal Gupta
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Priyadarshini Sanyal
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Centre for Cellular and Molecular Biology (CSIR-CCMB) Campus, Hyderabad, India
| | - Manisha Kochar
- Department of Zoology, University of Delhi, Delhi, India; CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | | | - Nitika Sangwan
- Department of Zoology, University of Delhi, Delhi, India
| | - Nishant Kumar
- Department of Zoology, University of Delhi, Delhi, India
| | - Ekta Tyagi
- Department of Zoology, University of Delhi, Delhi, India
| | - Simran Goel
- Department of Zoology, University of Delhi, Delhi, India
| | | | | | - Garima Khare
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
| | - Munia Ganguli
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Dominique Raze
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR9017 - CIIL - Centre for Infection and Immunity of Lille, Lille, France
| | - Camille Locht
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR9017 - CIIL - Centre for Infection and Immunity of Lille, Lille, France
| | | | - Meetu Gupta
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India.
| | - Vinay Kumar Nandicoori
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India; Academy of Scientific and Innovative Research (AcSIR), CSIR- Centre for Cellular and Molecular Biology (CSIR-CCMB) Campus, Hyderabad, India; National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India.
| | - Yogendra Singh
- Department of Zoology, University of Delhi, Delhi, India; Delhi School of Public Health, Institution of Eminence, University of Delhi, Delhi, India.
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Shamma F, Rego EH, Boutte CC. Mycobacterial serine/threonine phosphatase PstP is phosphoregulated and localized to mediate control of cell wall metabolism. Mol Microbiol 2022; 118:47-60. [PMID: 35670057 PMCID: PMC10070032 DOI: 10.1111/mmi.14951] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/12/2022] [Accepted: 06/01/2022] [Indexed: 11/26/2022]
Abstract
The mycobacterial cell wall is profoundly regulated in response to environmental stresses, and this regulation contributes to antibiotic tolerance. The reversible phosphorylation of different cell wall regulatory proteins is a major mechanism of cell wall regulation. Eleven serine/threonine protein kinases phosphorylate many critical cell wall-related proteins in mycobacteria. PstP is the sole serine/ threonine phosphatase, but few proteins have been verified as PstP substrates. PstP is itself phosphorylated, but the role of its phosphorylation in regulating its activity has been unclear. In this study, we aim to discover novel substrates of PstP in Mycobacterium tuberculosis (Mtb). We show in vitro that PstP dephosphorylates two regulators of peptidoglycan in Mtb, FhaA, and Wag31. We also show that a phosphomimetic mutation of T137 on PstP negatively regulates its catalytic activity against the cell wall regulators FhaA, Wag31, CwlM, PknB, and PknA, and that the corresponding mutation in Mycobacterium smegmatis causes misregulation of peptidoglycan in vivo. We show that PstP is localized to the septum, which likely restricts its access to certain substrates. These findings on the regulation of PstP provide insight into the control of cell wall metabolism in mycobacteria.
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Affiliation(s)
- Farah Shamma
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
| | - E Hesper Rego
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Cara C Boutte
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
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3
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Bacillus anthracis chain length, a virulence determinant, is regulated by membrane localized serine/threonine protein kinase PrkC. J Bacteriol 2021; 203:JB.00582-20. [PMID: 33753466 PMCID: PMC8117516 DOI: 10.1128/jb.00582-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anthrax is a zoonotic disease caused by Bacillus anthracis, a spore-forming pathogen that displays a chaining phenotype. It has been reported that the chaining phenotype acts as a virulence factor in B. anthracis In this study, we identify a serine/threonine protein kinase of B. anthracis, PrkC, the only kinase localized at the bacteria-host interface, as a determinant of B. anthracis chain length. In vitro, prkC disruption strain (BAS ΔprkC) grew as shorter chains throughout the bacterial growth cycle. A comparative analysis between the parent strain and BAS ΔprkC indicated that the levels of proteins, BslO and Sap, associated with the regulation of the bacterial chain length, were upregulated in BAS ΔprkC BslO is a septal murein hydrolase that catalyzes daughter cell separation and Sap is an S-layer structural protein required for the septal localization of BslO. PrkC disruption also has a significant effect on bacterial growth, cell wall thickness, and septa formation. Upregulation of ftsZ in BAS ΔprkC was also observed. Altogether, our results indicate that PrkC is required for maintaining optimum growth, cell wall homeostasis and most importantly - for the maintenance of the chaining phenotype.IMPORTANCEChaining phenotype acts as a virulence factor in Bacillus anthracis This is the first study that identifies a 'signal transduction protein' with an ability to regulate the chaining phenotype in Bacillus anthracis We show that the disruption of the lone surface-localized serine/threonine protein kinase, PrkC, leads to the shortening of the bacterial chains. We report upregulation of the de-chaining proteins in the PrkC disruption strain. Apart from this, we also report for the first time that PrkC disruption results in an attenuated cell growth, a decrease in the cell wall thickness and aberrant cell septa formation during the logarithmic phase of growth - a growth phase where PrkC is expressed maximally.
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ClpC-Mediated Sporulation Regulation at Engulfment Stage in Bacillus anthracis. Indian J Microbiol 2021; 61:170-179. [PMID: 33927458 DOI: 10.1007/s12088-021-00927-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/23/2021] [Indexed: 12/24/2022] Open
Abstract
Bacterial sporulation is a conserved process utilized by members of Bacillus genus and Clostridium in response to stress such as nutrient or temperature. Sporulation initiation is triggered by stress signals perceived by bacterial cell that leads to shutdown of metabolic pathways of bacterial cells. The mechanism of sporulation involves a complex network that is regulated at various checkpoints to form the viable bacterial spore. Engulfment is one such check point that drives the required cellular rearrangement necessary for the spore assembly and is mediated by bacterial proteolytic machinery that involves association of various Clp ATPases and ClpP protease. The present study highlights the importance of degradation of an anti-sigma factor F, SpoIIAB by ClpCP proteolytic machinery playing a crucial role in culmination of engulfment process during the sporulation in Bacillus anthracis.
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Rens C, Chao JD, Sexton DL, Tocheva EI, Av-Gay Y. Roles for phthiocerol dimycocerosate lipids in Mycobacterium tuberculosis pathogenesis. MICROBIOLOGY-SGM 2021; 167. [PMID: 33629944 DOI: 10.1099/mic.0.001042] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The success of Mycobacterium tuberculosis as a pathogen is well established: tuberculosis is the leading cause of death by a single infectious agent worldwide. The threat of multi- and extensively drug-resistant bacteria has renewed global concerns about this pathogen and understanding its virulence strategies will be essential in the fight against tuberculosis. The current review will focus on phthiocerol dimycocerosates (PDIMs), a long-known and well-studied group of complex lipids found in the M. tuberculosis cell envelope. Numerous studies show a role for PDIMs in several key steps of M. tuberculosis pathogenesis, with recent studies highlighting its involvement in bacterial virulence, in association with the ESX-1 secretion system. Yet, the mechanisms by which PDIMs help M. tuberculosis to control macrophage phagocytosis, inhibit phagosome acidification and modulate host innate immunity, remain to be fully elucidated.
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Affiliation(s)
- Céline Rens
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Joseph D Chao
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Danielle L Sexton
- Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
| | - Elitza I Tocheva
- Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
| | - Yossef Av-Gay
- Division of Infectious Disease, Department of Medicine, The University of British Columbia, Vancouver, Canada.,Department of Microbiology & Immunology, The University of British Columbia, Vancouver, Canada
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Phosphorylation on PstP Regulates Cell Wall Metabolism and Antibiotic Tolerance in Mycobacterium smegmatis. J Bacteriol 2021; 203:JB.00563-20. [PMID: 33257524 DOI: 10.1128/jb.00563-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 11/18/2020] [Indexed: 12/18/2022] Open
Abstract
Mycobacterium tuberculosis and its relatives, like many bacteria, have dynamic cell walls that respond to environmental stresses. Modulation of cell wall metabolism in stress is thought to be responsible for decreased permeability and increased tolerance to antibiotics. The signaling systems that control cell wall metabolism under stress, however, are poorly understood. Here, we examine the cell wall regulatory function of a key cell wall regulator, the serine/threonine phosphatase PstP, in the model organism Mycobacterium smegmatis We show that the peptidoglycan regulator CwlM is a substrate of PstP. We find that a phosphomimetic mutation, pstP T171E, slows growth, misregulates both mycolic acid and peptidoglycan metabolism in different conditions, and interferes with antibiotic tolerance. These data suggest that phosphorylation on PstP affects its activity against various substrates and is important in the transition between growth and stasis.IMPORTANCE Regulation of cell wall assembly is essential for bacterial survival and contributes to pathogenesis and antibiotic tolerance in mycobacteria, including pathogens such as Mycobacterium tuberculosis However, little is known about how the cell wall is regulated in stress. We describe a pathway of cell wall modulation in Mycobacterium smegmatis through the only essential Ser/Thr phosphatase, PstP. We showed that phosphorylation on PstP is important in regulating peptidoglycan metabolism in the transition to stasis and mycolic acid metabolism in growth. This regulation also affects antibiotic tolerance in growth and stasis. This work helps us to better understand the phosphorylation-mediated cell wall regulation circuitry in Mycobacteria.
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Park EJ, Kwon YM, Lee JW, Kang HY, Oh JI. Dual control of RegX3 transcriptional activity by SenX3 and PknB. J Biol Chem 2019; 294:11023-11034. [PMID: 31160336 DOI: 10.1074/jbc.ra119.008232] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/30/2019] [Indexed: 01/08/2023] Open
Abstract
The mycobacterial SenX3-RegX3 two-component system consists of the SenX3 sensor histidine kinase and its cognate RegX3 response regulator. This system is a phosphorelay-based regulatory system involved in sensing environmental Pi levels and induction of genes required for Pi acquisition under Pi-limiting conditions. Here we demonstrate that overexpression of the kinase domain of Mycobacterium tuberculosis PknB (PknB-KDMtb) inhibits the transcriptional activity of RegX3 of both M. tuberculosis and Mycobacterium smegmatis (RegX3Mtb and RegX3Ms, respectively). Mass spectrometry results, along with those of in vitro phosphorylation and complementation analyses, revealed that PknB kinase activity inhibits the transcriptional activity of RegX3Mtb through phosphorylation events at Thr-100, Thr-191, and Thr-217. Electrophoretic mobility shift assays disclosed that phosphorylation of Thr-191 and Thr-217 abolishes the DNA-binding ability of RegX3Mtb and that Thr-100 phosphorylation likely prevents RegX3Mtb from being activated through conformational changes induced by SenX3-mediated phosphorylation. We propose that the convergence of the PknB and SenX3-RegX3 signaling pathways might enable mycobacteria to integrate environmental Pi signals with the cellular replication state to adjust gene expression in response to Pi availability.
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Affiliation(s)
- Eun-Jin Park
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
| | - Yu-Mi Kwon
- Biomedical Research Institute, Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea, and; Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Jin-Won Lee
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Ho-Young Kang
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
| | - Jeong-Il Oh
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea,.
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8
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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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Tuning the Mycobacterium tuberculosis Alternative Sigma Factor SigF through the Multidomain Regulator Rv1364c and Osmosensory Kinase Protein Kinase D. J Bacteriol 2019; 201:JB.00725-18. [PMID: 30642988 DOI: 10.1128/jb.00725-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 01/02/2019] [Indexed: 12/20/2022] Open
Abstract
Bacterial alternative sigma factors are mostly regulated by a partner-switching mechanism. Regulation of the virulence-associated alternative sigma factor SigF of Mycobacterium tuberculosis has been an area of intrigue, with SigF having more predicted regulators than other sigma factors in this organism. Rv1364c is one such predicted regulator, the mechanism of which is confounded by the presence of both anti-sigma factor and anti-sigma factor antagonist functions in a single polypeptide. Using protein binding and phosphorylation assays, we demonstrate that the anti-sigma factor domain of Rv1364c mediates autophosphorylation of its antagonist domain and binds efficiently to SigF. Furthermore, we identified a direct role for the osmosensor serine/threonine kinase PknD in regulating the SigF-Rv1364c interaction, adding to the current understanding about the intersection of these discrete signaling networks. Phosphorylation of SigF also showed functional implications in its DNA binding ability, which may help in activation of the regulon. In M. tuberculosis, osmotic stress-dependent induction of espA, a SigF target involved in maintaining cell wall integrity, is curtailed upon overexpression of Rv1364c, showing its role as an anti-SigF factor. Overexpression of Rv1364c led to induction of another target, pks6, involved in lipid metabolism. This induction was, however, curtailed in the presence of osmotic stress conditions, suggesting modulation of SigF target gene expression via Rv1364c. These data provide evidence that Rv1364c acts an independent SigF regulator that is sensitive to the osmosensory signal, mediating the cross talk of PknD with the SigF regulon.IMPORTANCE Mycobacterium tuberculosis, capable of latently infecting the host and causing aggressive tissue damage during active tuberculosis, is endowed with a complex regulatory capacity built of several sigma factors, protein kinases, and phosphatases. These proteins regulate expression of genes that allow the bacteria to adapt to various host-derived stresses, like nutrient starvation, acidic pH, and hypoxia. The cross talk between these systems is not well understood. SigF is one such regulator of gene expression that helps M. tuberculosis to adapt to stresses and imparts virulence. This work provides evidence for its inhibition by the multidomain regulator Rv1364c and activation by the kinase PknD. The coexistence of negative and positive regulators of SigF in pathogenic bacteria reveals an underlying requirement for tight control of virulence factor expression.
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10
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New substrates and interactors of the mycobacterial Serine/Threonine protein kinase PknG identified by a tailored interactomic approach. J Proteomics 2019; 192:321-333. [DOI: 10.1016/j.jprot.2018.09.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/27/2018] [Accepted: 09/25/2018] [Indexed: 11/18/2022]
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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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12
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Effect of Homocysteine on Biofilm Formation by Mycobacteria. Indian J Microbiol 2018; 58:287-293. [PMID: 30013272 DOI: 10.1007/s12088-018-0739-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 05/03/2018] [Indexed: 12/29/2022] Open
Abstract
Mycobacteria show peculiar aggregated outgrowth like biofilm on the surface of solid or liquid media. Biofilms harbor antibiotic resistant bacteria in a self-produced extracellular matrix that signifies the bacterial fate to sedentary existence. Despite years of research, very little is known about the mechanisms that contribute to biofilm formation. LuxS has been previously known to play a role in biofilm formation in Autoinducer-2 dependent manner. We here show the effect of LuxS product-homocysteine, on the biofilm forming ability of non-tuberculous mycobacteria, Mycobacterium smegmatis and Mycobacterium bovis BCG showing AI-2 independent phenotypic effect of LuxS. Exogenous supplementation of homocysteine in the culture media leads to aberrant cording, pellicle outgrowth, and biofilm formation. Thus, our study contributes to the better understanding of the mechanism of mycobacterial biofilm formation and sheds light on the role of LuxS product homocysteine. In addition, we highlight the contribution of activated methyl cycle in bacterial quorum sensing.
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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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Glass LN, Swapna G, Chavadi SS, Tufariello JM, Mi K, Drumm JE, Lam TT, Zhu G, Zhan C, Vilchéze C, Arcos J, Chen Y, Bi L, Mehta S, Porcelli SA, Almo SC, Yeh SR, Jacobs WR, Torrelles JB, Chan J. Mycobacterium tuberculosis universal stress protein Rv2623 interacts with the putative ATP binding cassette (ABC) transporter Rv1747 to regulate mycobacterial growth. PLoS Pathog 2017; 13:e1006515. [PMID: 28753640 PMCID: PMC5549992 DOI: 10.1371/journal.ppat.1006515] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 08/09/2017] [Accepted: 07/06/2017] [Indexed: 12/25/2022] Open
Abstract
We have previously shown that the Mycobacterium tuberculosis universal stress protein Rv2623 regulates mycobacterial growth and may be required for the establishment of tuberculous persistence. Here, yeast two-hybrid and affinity chromatography experiments have demonstrated that Rv2623 interacts with one of the two forkhead-associated domains (FHA I) of Rv1747, a putative ATP-binding cassette transporter annotated to export lipooligosaccharides. FHA domains are signaling protein modules that mediate protein-protein interactions to modulate a wide variety of biological processes via binding to conserved phosphorylated threonine (pT)-containing oligopeptides of the interactors. Biochemical, immunochemical and mass spectrometric studies have shown that Rv2623 harbors pT and specifically identified threonine 237 as a phosphorylated residue. Relative to wild-type Rv2623 (Rv2623WT), a mutant protein in which T237 has been replaced with a non-phosphorylatable alanine (Rv2623T237A) exhibits decreased interaction with the Rv1747 FHA I domain and diminished growth-regulatory capacity. Interestingly, compared to WT bacilli, an M. tuberculosis Rv2623 null mutant (ΔRv2623) displays enhanced expression of phosphatidyl-myo-inositol mannosides (PIMs), while the ΔRv1747 mutant expresses decreased levels of PIMs. Animal studies have previously shown that ΔRv2623 is hypervirulent, while ΔRv1747 is growth-attenuated. Collectively, these data have provided evidence that Rv2623 interacts with Rv1747 to regulate mycobacterial growth; and this interaction is mediated via the recognition of the conserved Rv2623 pT237-containing FHA-binding motif by the Rv1747 FHA I domain. The divergent aberrant PIM profiles and the opposing in vivo growth phenotypes of ΔRv2623 and ΔRv1747, together with the annotated lipooligosaccharide exporter function of Rv1747, suggest that Rv2623 interacts with Rv1747 to modulate mycobacterial growth by negatively regulating the activity of Rv1747; and that Rv1747 might function as a transporter of PIMs. Because these glycolipids are major mycobacterial cell envelope components that can impact on the immune response, our findings raise the possibility that Rv2623 may regulate bacterial growth, virulence, and entry into persistence, at least in part, by modulating the levels of bacillary PIM expression, perhaps through negatively regulating the Rv1747-dependent export of the immunomodulatory PIMs to alter host-pathogen interaction, thereby influencing the fate of M. tuberculosis in vivo.
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Affiliation(s)
- Lisa N. Glass
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Ganduri Swapna
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Sivagami Sundaram Chavadi
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - JoAnn M. Tufariello
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Kaixia Mi
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Joshua E. Drumm
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - TuKiet T. Lam
- MS & Proteomics Resource of the W.M. Keck Biotechnology Resource Laboratory, Yale University School Medicine, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Guofeng Zhu
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Chenyang Zhan
- Department of Biochemistry, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Catherine Vilchéze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Howard Hughes Medical Institute, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Jesus Arcos
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Yong Chen
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Lijun Bi
- Department of Medicine, School of Stomatology and Medicine, Foshan University, Foshan, China
| | - Simren Mehta
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Steven A. Porcelli
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Steve C. Almo
- Department of Biochemistry, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Syun-Ru Yeh
- Departments of Physiology & Biophysics, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - William R. Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Howard Hughes Medical Institute, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Jordi B. Torrelles
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - John Chan
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
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15
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Ser/Thr protein kinase PrkC-mediated regulation of GroEL is critical for biofilm formation in Bacillus anthracis. NPJ Biofilms Microbiomes 2017. [PMID: 28649408 PMCID: PMC5460178 DOI: 10.1038/s41522-017-0015-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
PrkC is a conserved Ser/Thr protein kinase encoded in Bacillus anthracis genome. PrkC is shown to be important for B. anthracis pathogenesis, but little is known about its other functions and phosphorylated substrates. Systemic analyses indicate the compelling role of PrkC in phosphorylating multiple substrates, including the essential chaperone GroEL. Through mass spectrometry, we identified that PrkC phosphorylates GroEL on six threonine residues that are distributed in three canonical regions. Phosphorylation facilitates the oligomerization of GroEL to the physiologically active tetradecameric state and increases its affinity toward the co-chaperone GroES. Deletion of prkC in B. anthracis abrogates its ability to form biofilm. Overexpression of native GroEL recovers the biofilm-forming ability of prkC deletion strain. Similar overexpression of GroEL phosphorylation site mutants (Thr to Ala) does not augment biofilm formation. Further analyses indicate the phosphorylation of GroEL in diverse bacterial species. Thus, our results suggest that PrkC regulates biofilm formation by modulating the GroEL activity in a phosphorylation-dependent manner. The study deciphers the molecular signaling events that are important for biofilm formation in B. anthracis. An enzyme that adds phosphate groups to other proteins, PrkC, mediates molecular signaling events that allow anthrax bacteria to form biofilms. Bacillus anthracis is widely used as a model to explore the formation of biofilms that allows many bacterial infections to resist immune defenses. An international research team led by Yogendra Singh and Andaleeb Sajid at the CSIR-Institute of Genomics and Integrative Biology in Delhi, India, studied the bacterial protein kinase PrkC. The researchers found that PrkC phosphorylates a “chaperone” protein that assist the assembly and disassembly of other protein-based structures. This signaling protein and the chaperone help in biofilm formation. Establishing this link in the signaling chain leading to biofilms will guide future research to combat the role of biofilms in disease.
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16
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Chalut C. MmpL transporter-mediated export of cell-wall associated lipids and siderophores in mycobacteria. Tuberculosis (Edinb) 2016; 100:32-45. [DOI: 10.1016/j.tube.2016.06.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/23/2016] [Indexed: 10/21/2022]
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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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18
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Sharma V, Sharma P, Selvapandiyan A, Salotra P. Leishmania donovani-specific Ub-related modifier-1: an early endosome-associated ubiquitin-like conjugation inLeishmania donovani. Mol Microbiol 2015; 99:597-610. [DOI: 10.1111/mmi.13253] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2015] [Indexed: 12/24/2022]
Affiliation(s)
- Vanila Sharma
- National Institute of Pathology (ICMR); Safdarjang Hospital Campus; New Delhi 110029 India
- Symbiosis School of Biomedical Sciences; Symbiosis International University; Pune 412115 Maharashtra India
| | - Paresh Sharma
- National Institute of Pathology (ICMR); Safdarjang Hospital Campus; New Delhi 110029 India
| | - Angamuthu Selvapandiyan
- Institute of Molecular Medicine; 254 Okhla Industrial Estate, Phase III New Delhi 110020 India
| | - Poonam Salotra
- National Institute of Pathology (ICMR); Safdarjang Hospital Campus; New Delhi 110029 India
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Sajid A, Arora G, Singhal A, Kalia VC, Singh Y. Protein Phosphatases of Pathogenic Bacteria: Role in Physiology and Virulence. Annu Rev Microbiol 2015; 69:527-47. [DOI: 10.1146/annurev-micro-020415-111342] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Andaleeb Sajid
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
| | - Gunjan Arora
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
| | - Anshika Singhal
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
| | - Vipin C. Kalia
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
| | - Yogendra Singh
- Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Delhi 110007, India;
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20
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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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21
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Touchette MH, Bommineni GR, Delle Bovi RJ, Gadbery JE, Nicora CD, Shukla AK, Kyle JE, Metz TO, Martin DW, Sampson NS, Miller WT, Tonge PJ, Seeliger JC. Diacyltransferase Activity and Chain Length Specificity of Mycobacterium tuberculosis PapA5 in the Synthesis of Alkyl β-Diol Lipids. Biochemistry 2015; 54:5457-68. [PMID: 26271001 DOI: 10.1021/acs.biochem.5b00455] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although they are classified as Gram-positive bacteria, Corynebacterineae possess an asymmetric outer membrane that imparts structural and thereby physiological similarity to more distantly related Gram-negative bacteria. Like lipopolysaccharide in Gram-negative bacteria, lipids in the outer membrane of Corynebacterineae have been associated with the virulence of pathogenic species such as Mycobacterium tuberculosis (Mtb). For example, Mtb strains that lack long, branched-chain alkyl esters known as dimycocerosates (DIMs) are significantly attenuated in model infections. The resultant interest in the biosynthetic pathway of these unusual virulence factors has led to the elucidation of many of the steps leading to the final esterification of the alkyl β-diol, phthiocerol, with branched-chain fatty acids known as mycocerosates. PapA5 is an acyltransferase implicated in these final reactions. Here, we show that PapA5 is indeed the terminal enzyme in DIM biosynthesis by demonstrating its dual esterification activity and chain-length preference using synthetic alkyl β-diol substrate analogues. By applying these analogues to a series of PapA5 mutants, we also revise a model for the substrate binding within PapA5. Finally, we demonstrate that the Mtb Ser/Thr kinases PknB and PknE modify PapA5 on three overlapping Thr residues and that a fourth Thr is unique to PknE phosphorylation. These results clarify the DIM biosynthetic pathway and indicate post-translational modifications that warrant further elucidation for their roles in the regulation of DIM biosynthesis.
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Affiliation(s)
| | | | | | | | - Carrie D Nicora
- Biological Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Anil K Shukla
- Biological Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Jennifer E Kyle
- Biological Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Thomas O Metz
- Biological Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
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22
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Nakedi KC, Nel AJM, Garnett S, Blackburn JM, Soares NC. Comparative Ser/Thr/Tyr phosphoproteomics between two mycobacterial species: the fast growing Mycobacterium smegmatis and the slow growing Mycobacterium bovis BCG. Front Microbiol 2015; 6:237. [PMID: 25904896 PMCID: PMC4389566 DOI: 10.3389/fmicb.2015.00237] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 03/10/2015] [Indexed: 11/13/2022] Open
Abstract
Ser/Thr/Tyr protein phosphorylation plays a critical role in regulating mycobacterial growth and development. Understanding the mechanistic link between protein phosphorylation signaling network and mycobacterial growth rate requires a global view of the phosphorylation events taking place at a given time under defined conditions. In the present study we employed a phosphopeptide enrichment and high throughput mass spectrometry-based strategy to investigate and qualitatively compare the phosphoproteome of two mycobacterial model organisms: the fast growing Mycobacterium smegmatis and the slow growing Mycobacterium bovis BCG. Cells were harvested during exponential phase and our analysis detected a total of 185 phospho-sites in M. smegmatis, of which 106 were confidently localized [localization probability (LP) = 0.75; PEP = 0.01]. By contrast, in M. bovis BCG the phosphoproteome comprised 442 phospho-sites, of which 289 were confidently localized. The percentage distribution of Ser/Thr/Tyr phosphorylation was 39.47, 57.02, and 3.51% for M. smegmatis and 35, 61.6, and 3.1% for M. bovis BCG. Moreover, our study identified a number of conserved Ser/Thr phosphorylated sites and conserved Tyr phosphorylated sites across different mycobacterial species. Overall a qualitative comparison of the fast and slow growing mycobacteria suggests that the phosphoproteome of M. smegmatis is a simpler version of that of M. bovis BCG. In particular, M. bovis BCG exponential cells exhibited a much more complex and sophisticated protein phosphorylation network regulating important cellular cycle events such as cell wall biosynthesis, elongation, cell division including immediately response to stress. The differences in the two phosphoproteomes are discussed in light of different mycobacterial growth rates.
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Affiliation(s)
| | | | | | - Jonathan M. Blackburn
- Blackburn Lab, Applied Proteomics and Chemical Biology Group, Division of Medical Biochemistry, Institute of Infectious Disease and Molecular Medicine, University of Cape TownCape Town, South Africa
| | - Nelson C. Soares
- Blackburn Lab, Applied Proteomics and Chemical Biology Group, Division of Medical Biochemistry, Institute of Infectious Disease and Molecular Medicine, University of Cape TownCape Town, South Africa
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Identification of Ser/Thr kinase and forkhead associated domains in Mycobacterium ulcerans: characterization of novel association between protein kinase Q and MupFHA. PLoS Negl Trop Dis 2014; 8:e3315. [PMID: 25412098 PMCID: PMC4238996 DOI: 10.1371/journal.pntd.0003315] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 10/04/2014] [Indexed: 11/24/2022] Open
Abstract
Background Mycobacterium ulcerans, the causative agent of Buruli ulcer in humans, is unique among the members of Mycobacterium genus due to the presence of the virulence determinant megaplasmid pMUM001. This plasmid encodes multiple virulence-associated genes, including mup011, which is an uncharacterized Ser/Thr protein kinase (STPK) PknQ. Methodology/Principal Findings In this study, we have characterized PknQ and explored its interaction with MupFHA (Mup018c), a FHA domain containing protein also encoded by pMUM001. MupFHA was found to interact with PknQ and suppress its autophosphorylation. Subsequent protein-protein docking and molecular dynamic simulation analyses showed that this interaction involves the FHA domain of MupFHA and PknQ activation loop residues Ser170 and Thr174. FHA domains are known to recognize phosphothreonine residues, and therefore, MupFHA may be acting as one of the few unusual FHA-domain having overlapping specificity. Additionally, we elucidated the PknQ-dependent regulation of MupDivIVA (Mup012c), which is a DivIVA domain containing protein encoded by pMUM001. MupDivIVA interacts with MupFHA and this interaction may also involve phospho-threonine/serine residues of MupDivIVA. Conclusions/Significance Together, these results describe novel signaling mechanisms in M. ulcerans and show a three-way regulation of PknQ, MupFHA, and MupDivIVA. FHA domains have been considered to be only pThr specific and our results indicate a novel mechanism of pSer as well as pThr interaction exhibited by MupFHA. These results signify the need of further re-evaluating the FHA domain –pThr/pSer interaction model. MupFHA may serve as the ideal candidate for structural studies on this unique class of modular enzymes. Mycobacterium ulcerans is a slow growing pathogen, which is prevalent in many tropical and sub-tropical countries. M. ulcerans possesses unique signaling pathways with only 13 STPK containing genes. This is strikingly different from its closest homolog Mycobacterium marinum and surprisingly closer to the human pathogen, Mycobacterium tuberculosis. PknQ, MupFHA and MupDivIVA are regulatory proteins encoded by the virulence determining plasmid pMUM001 of M. ulcerans. In addition to characterizing the STPK, we focused on deciphering the basis of interaction between the three partner proteins leading to the identification of critical residues. Present study describes the newly identified phosphoserine-based interactions, which is unique amongst the FHA-domain containing proteins. We confirmed our results using structural analysis via specific mutants and their interaction profiles. Importantly, these data highlight the significance of FHA domains and their role in understanding cellular signaling. This work will encourage further studies to elucidate role of M. ulcerans signaling systems. It will also raise questions like how less studied tropical bacterial pathogens acquire eukaryotic-like Ser/Thr protein kinase and exhibit unusual mechanisms to interact with its partner domains.
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Cui T, He ZG. Improved understanding of pathogenesis from protein interactions inMycobacteriumtuberculosis. Expert Rev Proteomics 2014; 11:745-55. [DOI: 10.1586/14789450.2014.971762] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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HupB, a nucleoid-associated protein of Mycobacterium tuberculosis, is modified by serine/threonine protein kinases in vivo. J Bacteriol 2014; 196:2646-57. [PMID: 24816602 DOI: 10.1128/jb.01625-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HU, a widely conserved bacterial histone-like protein, regulates many genes, including those involved in stress response and virulence. Whereas ample data are available on HU-DNA communication, the knowledge on how HU perceives a signal and transmit it to DNA remains limited. In this study, we identify HupB, the HU homolog of the human pathogen Mycobacterium tuberculosis, as a component of serine/threonine protein kinase (STPK) signaling. HupB is extracted in its native state from the exponentially growing cells of M. tuberculosis H37Ra and is shown to be phosphorylated on both serine and threonine residues. The STPKs capable of modifying HupB are determined in vitro and the residues modified by the STPKs are identified for both in vivo and the in vitro proteins through mass spectrometry. Of the identified phosphosites, Thr(65) and Thr(74) in the DNA-embracing β-strand of the N-terminal domain of HupB (N-HupB) are shown to be crucial for its interaction with DNA. In addition, Arg(55) is also identified as an important residue for N-HupB-DNA interaction. N-HupB is shown to have a diminished interaction with DNA after phosphorylation. Furthermore, hupB is shown to be maximally expressed during the stationary phase in M. tuberculosis H37Ra, while HupB kinases were found to be constitutively expressed (PknE and PknF) or most abundant during the exponential phase (PknB). In conclusion, HupB, a DNA-binding protein, with an ability to modulate chromatin structure is proposed to work in a growth-phase-dependent manner through its phosphorylation carried out by the mycobacterial STPKs.
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Lin JS, Wu HH, Hsu PH, Ma LS, Pang YY, Tsai MD, Lai EM. Fha interaction with phosphothreonine of TssL activates type VI secretion in Agrobacterium tumefaciens. PLoS Pathog 2014; 10:e1003991. [PMID: 24626341 PMCID: PMC3953482 DOI: 10.1371/journal.ppat.1003991] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 01/27/2014] [Indexed: 11/26/2022] Open
Abstract
The type VI secretion system (T6SS) is a widespread protein secretion system found in many Gram-negative bacteria. T6SSs are highly regulated by various regulatory systems at multiple levels, including post-translational regulation via threonine (Thr) phosphorylation. The Ser/Thr protein kinase PpkA is responsible for this Thr phosphorylation regulation, and the forkhead-associated (FHA) domain-containing Fha-family protein is the sole T6SS phosphorylation substrate identified to date. Here we discovered that TssL, the T6SS inner-membrane core component, is phosphorylated and the phosphorylated TssL (p-TssL) activates type VI subassembly and secretion in a plant pathogenic bacterium, Agrobacterium tumefaciens. Combining genetic and biochemical approaches, we demonstrate that TssL is phosphorylated at Thr 14 in a PpkA-dependent manner. Further analysis revealed that the PpkA kinase activity is responsible for the Thr 14 phosphorylation, which is critical for the secretion of the T6SS hallmark protein Hcp and the putative toxin effector Atu4347. TssL phosphorylation is not required for the formation of the TssM-TssL inner-membrane complex but is critical for TssM conformational change and binding to Hcp and Atu4347. Importantly, Fha specifically interacts with phosphothreonine of TssL via its pThr-binding motif in vivo and in vitro and this interaction is crucial for TssL interaction with Hcp and Atu4347 and activation of type VI secretion. In contrast, pThr-binding ability of Fha is dispensable for TssM structural transition. In conclusion, we discover a novel Thr phosphorylation event, in which PpkA phosphorylates TssL to activate type VI secretion via its direct binding to Fha in A. tumefaciens. A model depicting an ordered TssL phosphorylation-induced T6SS assembly pathway is proposed. The bacterial type VI secretion system (T6SS) resembles a contractile phage tail structure and functions to deliver effectors to eukaryotic or prokaryotic target cells for the survival of many pathogenic bacteria. T6SS is highly regulated by various regulatory systems at multiple levels in response to environmental cues. Post-translational regulation via threonine (Thr) phosphorylation is an emerging theme in regulating prokaryotic signaling, including T6SS; the knowledge is mainly contributed by studies of Hcp secretion island 1-encoded T6SS (H1-T6SS) of Pseudomonas aeruginosa. Here, we discover a new phosphorylated target, a T6SS core-component TssL, and demonstrate that this Thr phosphorylation event post-translationally regulates type VI secretion in a plant pathogenic bacterium, Agrobacterium tumefaciens. We provide the first demonstration that the specific binding of Fha, a forkhead-associated domain-containing protein, to the phosphorylated target is required to stimulate type VI secretion. Genetic and biochemical data strongly suggest an ordered TssL-phosphorylation–dependent assembly and secretion pathway.
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Affiliation(s)
- Jer-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Hsin-Hui Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Structural Biology Program, National Tsing Hua University, Hsinchu, Taiwan; Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Pang-Hung Hsu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Genomics Research Center, Academia Sinica, Taipei, Taiwan; Department of Life Science, Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan
| | - Lay-Sun Ma
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yin-Yuin Pang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Ming-Daw Tsai
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Structural Biology Program, National Tsing Hua University, Hsinchu, Taiwan; Genomics Research Center, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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Regulation of homocysteine metabolism by Mycobacterium tuberculosis S-adenosylhomocysteine hydrolase. Sci Rep 2014; 3:2264. [PMID: 23877358 PMCID: PMC3719076 DOI: 10.1038/srep02264] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 07/08/2013] [Indexed: 12/28/2022] Open
Abstract
Mycobacterium tuberculosis modulates expression of various metabolism-related genes to adapt in the adverse host environment. The gene coding for M. tuberculosis S-adenosylhomocysteine hydrolase (Mtb-SahH) is essential for optimal growth and the protein product is involved in intermediary metabolism. However, the relevance of SahH in mycobacterial physiology is unknown. In this study, we analyze the role of Mtb-SahH in regulating homocysteine concentration in surrogate host Mycobacterium smegmatis. Mtb-SahH catalyzes reversible hydrolysis of S-adenosylhomocysteine to homocysteine and adenosine and we demonstrate that the conserved His363 residue is critical for bi-directional catalysis. Mtb-SahH is regulated by serine/threonine phosphorylation of multiple residues by M. tuberculosis PknB. Major phosphorylation events occur at contiguous residues Thr219, Thr220 and Thr221, which make pivotal contacts with cofactor NAD+. Consequently, phosphorylation negatively modulates affinity of enzyme towards NAD+ as well as SAH-synthesis. Thr219, Thr220 and Thr221 are essential for enzyme activity, and therefore, responsible for SahH-mediated regulation of homocysteine.
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Bhaduri A, Misra R, Maji A, Bhetaria PJ, Mishra S, Arora G, Singh LK, Dhasmana N, Dubey N, Virdi JS, Singh Y. Mycobacterium tuberculosis cyclophilin A uses novel signal sequence for secretion and mimics eukaryotic cyclophilins for interaction with host protein repertoire. PLoS One 2014; 9:e88090. [PMID: 24505389 PMCID: PMC3913756 DOI: 10.1371/journal.pone.0088090] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 01/03/2014] [Indexed: 11/19/2022] Open
Abstract
Cyclophilins are prolyl isomerases with multitude of functions in different cellular processes and pathological conditions. Cyclophilin A (PpiA) of Mycobacterium tuberculosis is secreted during infection in intraphagosomal niche. However, our understanding about the evolutionary origin, secretory mechanism or the interactome of M. tuberculosis PpiA is limited. This study demonstrates through phylogenetic and structural analyses that PpiA has more proximity to human cyclophilins than the prokaryotic counterparts. We report a unique N-terminal sequence (MADCDSVTNSP) present in pathogenic mycobacterial PpiA and absent in non-pathogenic strains. This sequence stretch was shown to be essential for PpiA secretion. The overexpression of full-length PpiA from M. tuberculosis in non-pathogenic Mycobacterium smegmatis resulted in PpiA secretion while truncation of the N-terminal stretch obstructed the secretion. In addition, presence of an ESX pathway substrate motif in M. tuberculosis PpiA suggested possible involvement of Type VII secretion system. Site-directed mutagenesis of key residues in this motif in full-length PpiA also hindered the secretion in M. smegmatis. Bacterial two-hybrid screens with human lung cDNA library as target were utilized to identify interaction partners of PpiA from host repertoire, and a number of substrates with functional representation in iron storage, signal transduction and immune responses were detected. The extensive host interactome coupled with the sequence and structural similarity to human cyclophilins is strongly suggestive of PpiA being deployed by M. tuberculosis as an effector mimic against the host cyclophilins.
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Affiliation(s)
- Asani Bhaduri
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
- Department of Microbiology, University of Delhi, Delhi, India
| | - Richa Misra
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - Abhijit Maji
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | | | - Sonakshi Mishra
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - Gunjan Arora
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | | | - Neha Dhasmana
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - Neha Dubey
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | | | - Yogendra Singh
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
- * E-mail: mail:
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Zinc regulates the activity of kinase-phosphatase pair (BasPrkC/BasPrpC) in Bacillus anthracis. Biometals 2013; 26:715-30. [PMID: 23793375 DOI: 10.1007/s10534-013-9646-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 06/09/2013] [Indexed: 01/02/2023]
Abstract
Bacillus anthracis Ser/Thr protein kinase PrkC (BasPrkC) is important for virulence of the bacterium within the host. Homologs of PrkC and its cognate phosphatase PrpC (BasPrpC) are the most conserved mediators of signaling events in diverse bacteria. BasPrkC homolog in Bacillus subtilis regulates critical processes like spore germination and BasPrpC modulates the activity of BasPrkC by dephosphorylation. So far, biochemical and genetic studies have provided important insights into the roles of BasPrkC and BasPrpC; however, regulation of their activities is not known. We studied the regulation of BasPrkC/BasPrpC pair and observed that Zn(2+) metal ions can alter their activities. Zn(2+) promotes BasPrkC kinase activity while inhibits the BasPrpC phosphatase activity. Concentration of Zn(2+) in growing B. anthracis cells was found to vary with growth phase. Zn(2+) was found to be lowest in log phase cells while it was highest in spores. This variation in Zn(2+) concentration is significant for understanding the antagonistic activities of BasPrkC/BasPrpC pair. Our results also show that BasPrkC activity is modulated by temperature changes and kinase inhibitors. Additionally, we identified Elongation Factor Tu (BasEf-Tu) as a substrate of BasPrkC/BasPrpC pair and assessed the impact of their regulation on BasEf-Tu phosphorylation. Based on these results, we propose Zn(2+) as an important regulator of BasPrkC/BasPrpC mediated phosphorylation cascades. Thus, this study reveals additional means by which BasPrkC can be activated leading to autophosphorylation and substrate phosphorylation.
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Abstract
Long-chain-length hydrophobic acyl residues play a vital role in a multitude of essential biological structures and processes. They build the inner hydrophobic layers of biological membranes, are converted to intracellular storage compounds, and are used to modify protein properties or function as membrane anchors, to name only a few functions. Acyl thioesters are transferred by acyltransferases or transacylases to a variety of different substrates or are polymerized to lipophilic storage compounds. Lipases represent another important enzyme class dealing with fatty acyl chains; however, they cannot be regarded as acyltransferases in the strict sense. This review provides a detailed survey of the wide spectrum of bacterial acyltransferases and compares different enzyme families in regard to their catalytic mechanisms. On the basis of their studied or assumed mechanisms, most of the acyl-transferring enzymes can be divided into two groups. The majority of enzymes discussed in this review employ a conserved acyltransferase motif with an invariant histidine residue, followed by an acidic amino acid residue, and their catalytic mechanism is characterized by a noncovalent transition state. In contrast to that, lipases rely on completely different mechanism which employs a catalytic triad and functions via the formation of covalent intermediates. This is, for example, similar to the mechanism which has been suggested for polyester synthases. Consequently, although the presented enzyme types neither share homology nor have a common three-dimensional structure, and although they deal with greatly varying molecule structures, this variety is not reflected in their mechanisms, all of which rely on a catalytically active histidine residue.
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Affiliation(s)
- Annika Röttig
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität, Münster, Germany
| | - Alexander Steinbüchel
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität, Münster, Germany
- Environmental Sciences Department, King Abdulaziz University, Jeddah, Saudi Arabia
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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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Wolfe LM, Veeraraghavan U, Idicula-Thomas S, Schürer S, Wennerberg K, Reynolds R, Besra GS, Dobos KM. A chemical proteomics approach to profiling the ATP-binding proteome of Mycobacterium tuberculosis. Mol Cell Proteomics 2013; 12:1644-60. [PMID: 23462205 PMCID: PMC3675820 DOI: 10.1074/mcp.m112.025635] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Tuberculosis, caused by Mycobacterium tuberculosis, remains one of the leading causes of death worldwide despite extensive research, directly observed therapy using multidrug regimens, and the widespread use of a vaccine. The majority of patients harbor the bacterium in a state of metabolic dormancy. New drugs with novel modes of action are needed to target essential metabolic pathways in M. tuberculosis; ATP-competitive enzyme inhibitors are one such class. Previous screening efforts for ATP-competitive enzyme inhibitors identified several classes of lead compounds that demonstrated potent anti-mycobacterial efficacy as well as tolerable levels of toxicity in cell culture. In this report, a probe-based chemoproteomic approach was used to selectively profile the M. tuberculosis ATP-binding proteome in normally growing and hypoxic M. tuberculosis. From these studies, 122 ATP-binding proteins were identified in either metabolic state, and roughly 60% of these are reported to be essential for survival in vitro. These data are available through ProteomeXchange with identifier PXD000141. Protein families vital to the survival of the tubercle bacillus during hypoxia emerged from our studies. Specifically, along with members of the DosR regulon, several proteins involved in energy metabolism (Icl/Rv0468 and Mdh/Rv1240) and lipid biosynthesis (UmaA/Rv0469, DesA1/Rv0824c, and DesA2/Rv1094) were found to be differentially abundant in hypoxic versus normal growing cultures. These pathways represent a subset of proteins that may be relevant therapeutic targets for development of novel ATP-competitive antibiotics.
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Affiliation(s)
- Lisa M Wolfe
- Department of Microbiology, Colorado State University, Fort Collins, Colorado 80523, USA
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Weiling H, Xiaowen Y, Chunmei L, Jianping X. Function and evolution of ubiquitous bacterial signaling adapter phosphopeptide recognition domain FHA. Cell Signal 2013. [DOI: 10.1016/j.cellsig.2012.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Gómez-Velasco A, Bach H, Rana AK, Cox LR, Bhatt A, Besra GS, Av-Gay Y. Disruption of the serine/threonine protein kinase H affects phthiocerol dimycocerosates synthesis in Mycobacterium tuberculosis. MICROBIOLOGY-SGM 2013; 159:726-736. [PMID: 23412844 PMCID: PMC3709824 DOI: 10.1099/mic.0.062067-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mycobacterium tuberculosis possesses a complex cell wall that is unique and essential for interaction of the pathogen with its human host. Emerging evidence suggests that the biosynthesis of complex cell-wall lipids is mediated by serine/threonine protein kinases (STPKs). Herein, we show, using in vivo radiolabelling, MS and immunostaining analyses, that targeted deletion of one of the STPKs, pknH, attenuates the production of phthiocerol dimycocerosates (PDIMs), a major M. tuberculosis virulence lipid. Comparative protein expression analysis revealed that proteins in the PDIM biosynthetic pathway are differentially expressed in a deleted pknH strain. Furthermore, we analysed the composition of the major lipoglycans, lipoarabinomannan (LAM) and lipomannan (LM), and found a twofold higher LAM/LM ratio in the mutant strain. Thus, we provide experimental evidence that PknH contributes to the production and synthesis of M. tuberculosis cell-wall components.
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Affiliation(s)
- Anaximandro Gómez-Velasco
- Department of Medicine, Division of Infectious Diseases, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Horacio Bach
- Department of Medicine, Division of Infectious Diseases, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Amrita K Rana
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Liam R Cox
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Apoorva Bhatt
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Yossef Av-Gay
- Department of Medicine, Division of Infectious Diseases, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
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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: 368] [Impact Index Per Article: 30.7] [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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Arora G, Sajid A, Arulanandh MD, Singhal A, Mattoo AR, Pomerantsev AP, Leppla SH, Maiti S, Singh Y. Unveiling the novel dual specificity protein kinases in Bacillus anthracis: identification of the first prokaryotic dual specificity tyrosine phosphorylation-regulated kinase (DYRK)-like kinase. J Biol Chem 2012; 287:26749-63. [PMID: 22711536 PMCID: PMC3411013 DOI: 10.1074/jbc.m112.351304] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 06/14/2012] [Indexed: 12/23/2022] Open
Abstract
Dual specificity protein kinases (DSPKs) are unique enzymes that can execute multiple functions in the cell, which are otherwise performed exclusively by serine/threonine and tyrosine protein kinases. In this study, we have characterized the protein kinases Bas2152 (PrkD) and Bas2037 (PrkG) from Bacillus anthracis. Transcriptional analyses of these kinases showed that they are expressed in all phases of growth. In a serendipitous discovery, both kinases were found to be DSPKs. PrkD was found to be similar to the eukaryotic dual specificity Tyr phosphorylation-regulated kinase class of dual specificity kinases, which autophosphorylates on Ser, Thr, and Tyr residues and phosphorylates Ser and Thr residues on substrates. PrkG was found to be a bona fide dual specificity protein kinase that mediates autophosphorylation and substrate phosphorylation on Ser, Thr, and Tyr residues. The sites of phosphorylation in both of the kinases were identified through mass spectrometry. Phosphorylation on Tyr residues regulates the kinase activity of PrkD and PrkG. PrpC, the only known Ser/Thr protein phosphatase, was also found to possess dual specificity. Genistein, a known Tyr kinase inhibitor, was found to inhibit the activities of PrkD and PrkG and affect the growth of B. anthracis cells, indicating a possible role of these kinases in cell growth and development. In addition, the glycolytic enzyme pyruvate kinase was found to be phosphorylated by PrkD on Ser and Thr residues but not by PrkG. Thus, this study provides the first evidence of DSPKs in B. anthracis that belong to different classes and have different modes of regulation.
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Affiliation(s)
- Gunjan Arora
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Andaleeb Sajid
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Mary Diana Arulanandh
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Anshika Singhal
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Abid R. Mattoo
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Andrei P. Pomerantsev
- the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202
| | - Stephen H. Leppla
- the Laboratory of Parasitic Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892-3202
| | - Souvik Maiti
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
| | - Yogendra Singh
- From the Council of Scientific and Industrial Research-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India and
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Roumestand C, Leiba J, Galophe N, Margeat E, Padilla A, Bessin Y, Barthe P, Molle V, Cohen-Gonsaud M. Structural insight into the Mycobacterium tuberculosis Rv0020c protein and its interaction with the PknB kinase. Structure 2012; 19:1525-34. [PMID: 22000520 DOI: 10.1016/j.str.2011.07.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 06/20/2011] [Accepted: 07/07/2011] [Indexed: 01/09/2023]
Abstract
The protein Rv0020c from Mycobacterium tuberculosis, also called FhaA, is one of the major substrates of the essential Ser/Thr protein kinase (STPK) PknB. The protein is composed of three domains and is phosphorylated on a unique site in its N terminus. We solved the solution structure of both N- and C-terminal domains and demonstrated that the approximately 300 amino acids of the intermediate domain are not folded. We present evidence that the FHA, a phosphospecific binding domain, of Rv0020c does not interact with the phosphorylated catalytic domains of PknB, but with the phosphorylated juxtamembrane domain that links the catalytic domain to the mycobacterial membrane. We also demonstrated that the degree and the pattern of phosphorylation of this juxtamembrane domain modulates the affinity of the substrate (Rv0020c) toward its kinase (PknB).
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Affiliation(s)
- Christian Roumestand
- CNRS UMR 5048, Centre de Biochimie Structurale, 29, rue de Navacelles 34090 Montpellier, France
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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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Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis, has a complex cellular envelope that comprises both the cytoplasmic membrane and the outer cell wall. Despite advances in elucidating the structural and biochemical composition of these features, the processes that ensure cell wall homeostasis remain poorly understood. New findings implicate the essential mycobacterial serine-threonine protein kinase (STPK), PknB, in regulating the formation of a regulatory complex that includes the integral membrane protein MviN, which is required for peptidoglycan biosynthesis, and a forkhead-associated (FHA) domain protein, FhaA. A model has emerged in which a peptidoglycan-derived muropeptide signal triggers the PknB-mediated phosphorylation of the MviN pseudokinase domain, which in turn recruits the FHA-containing regulatory protein to inhibit peptidoglycan biosynthesis at the cell poles and septum. In establishing PknB as central regulator of this pathway, the model reinforces the major role of this STPK network in the orchestration of fundamental mycobacterial processes, and, with the identification of MviN as having a catalytically inactive and highly divergent kinase homology domain, the model establishes a pseudokinase as a key player in cell wall metabolism.
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Affiliation(s)
- Digby F Warner
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit and DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Institute of Infectious Disease and Molecular Medicine, and Department of Clinical Laboratory Sciences, Faculty of Health Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa.
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Interaction of Mycobacterium tuberculosis elongation factor Tu with GTP is regulated by phosphorylation. J Bacteriol 2011; 193:5347-58. [PMID: 21803988 DOI: 10.1128/jb.05469-11] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
During protein synthesis, translation elongation factor Tu (Ef-Tu) is responsible for the selection and binding of the cognate aminoacyl-tRNA to the acceptor site on the ribosome. The activity of Ef-Tu is dependent on its interaction with GTP. Posttranslational modifications, such as phosphorylation, are known to regulate the activity of Ef-Tu in several prokaryotes. Although a study of the Mycobacterium tuberculosis phosphoproteome showed Ef-Tu to be phosphorylated, the role of phosphorylation in the regulation of Ef-Tu has not been studied. In this report, we show that phosphorylation of M. tuberculosis Ef-Tu (MtbEf-Tu) by PknB reduced its interaction with GTP, suggesting a concomitant reduction in the level of protein synthesis. Overexpression of PknB in Mycobacterium smegmatis indeed reduced the level of protein synthesis. MtbEf-Tu was found to be phosphorylated by PknB on multiple sites, including Thr118, which is required for optimal activity of the protein. We found that kirromycin, an Ef-Tu-specific antibiotic, had a significant effect on the nucleotide binding of unphosphorylated MtbEf-Tu but not on the phosphorylated protein. Our results show that the modulation of the MtbEf-Tu-GTP interaction by phosphorylation can have an impact on cellular protein synthesis and growth. These results also suggest that phosphorylation can change the sensitivity of the protein to the specific inhibitors. Thus, the efficacy of an inhibitor can also depend on the posttranslational modification(s) of the target and should be considered during the development of the molecule.
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Chakraborti PK, Matange N, Nandicoori VK, Singh Y, Tyagi JS, Visweswariah SS. Signalling mechanisms in Mycobacteria. Tuberculosis (Edinb) 2011; 91:432-40. [PMID: 21570916 DOI: 10.1016/j.tube.2011.04.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 03/28/2011] [Accepted: 04/10/2011] [Indexed: 11/18/2022]
Abstract
The importance of inter- and intracellular signal transduction in all forms of life cannot be underestimated. A large number of genes dedicated to cellular signalling are found in almost all sequenced genomes, and Mycobacteria are no exception. What appears to be interesting in Mycobacteria is that well characterized signalling mechanisms used by bacteria, such as the histidine-aspartate phosphorelay seen in two-component systems, are found alongside signalling components that closely mimic those seen in higher eukaryotes. This review will describe the important contribution made by researchers in India towards the identification and characterization of proteins involved in two-component signalling, protein phosphorylation and cyclic nucleotide metabolism.
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Sajid A, Arora G, Gupta M, Upadhyay S, Nandicoori VK, Singh Y. Phosphorylation of Mycobacterium tuberculosis Ser/Thr phosphatase by PknA and PknB. PLoS One 2011; 6:e17871. [PMID: 21423706 PMCID: PMC3052367 DOI: 10.1371/journal.pone.0017871] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 02/11/2011] [Indexed: 11/30/2022] Open
Abstract
Background The integrated functions of 11 Ser/Thr protein kinases (STPKs) and one
phosphatase manipulate the phosphorylation levels of critical proteins in
Mycobacterium tuberculosis. In this study, we show that
the lone Ser/Thr phosphatase (PstP) is regulated through phosphorylation by
STPKs. Principal Findings PstP is phosphorylated by PknA and PknB and phosphorylation is influenced by
the presence of Zn2+-ions and inorganic phosphate (Pi). PstP
is differentially phosphorylated on the cytosolic domain with
Thr137, Thr141, Thr174 and
Thr290 being the target residues of PknB while
Thr137 and Thr174 are phosphorylated by PknA. The
Mn2+-ion binding residues Asp38 and
Asp229 are critical for the optimal activity of PstP and
substitution of these residues affects its phosphorylation status. Native
PstP and its phosphatase deficient mutant PstPcD38G
are phosphorylated by PknA and PknB in E. coli and addition
of Zn2+/Pi in the culture conditions affect the
phosphorylation level of PstP. Interestingly, the phosphorylated phosphatase
is more active than its unphosphorylated equivalent. Conclusions and Significance This study establishes the novel mechanisms for regulation of mycobacterial
Ser/Thr phosphatase. The results indicate that STPKs and PstP may regulate
the signaling through mutually dependent mechanisms. Consequently, PstP
phosphorylation may play a critical role in regulating its own activity.
Since, the equilibrium between phosphorylated and non-phosphorylated states
of mycobacterial proteins is still unexplained, understanding the regulation
of PstP may help in deciphering the signal transduction pathways mediated by
STPKs and the reversibility of the phenomena.
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Affiliation(s)
- Andaleeb Sajid
- Institute of Genomics and Integrative Biology
(CSIR), Delhi, India
| | - Gunjan Arora
- Institute of Genomics and Integrative Biology
(CSIR), Delhi, India
| | - Meetu Gupta
- Institute of Genomics and Integrative Biology
(CSIR), Delhi, India
| | - Sandeep Upadhyay
- National Institute of Immunology, Aruna Asaf
Ali Marg, New Delhi, India
| | | | - Yogendra Singh
- Institute of Genomics and Integrative Biology
(CSIR), Delhi, India
- * E-mail:
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Jones G, Del Sol R, Dudley E, Dyson P. Forkhead-associated proteins genetically linked to the serine/threonine kinase PknB regulate carbon flux towards antibiotic biosynthesis in Streptomyces coelicolor. Microb Biotechnol 2010; 4:263-74. [PMID: 21342471 PMCID: PMC3818866 DOI: 10.1111/j.1751-7915.2010.00237.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
To date, the function of only two of the 34 predicted serine/threonine protein kinases (STPKs) of Streptomyces coelicolor has been described. Here we report functional analysis of pknB and two linked genes, fhaAB, encoding forkhead‐associated (FHA) domain proteins that are part of a highly conserved gene locus in actinobacteria. In contrast to the homologous gene of Mycobacterium tuberculosis, pknB in S. coelicolor is not essential and has no apparent role in defining cell shape. Phosphorylation of recombinant forms of both the full‐length protein and N‐terminal kinase domain suggest that PknB‐mediated signalling in S. coelicolor may be modulated by another factor(s). FhaAB are candidate interacting partners of PknB and loss of their function resulted in deregulation of central carbon metabolism, with carbon flux diverted to synthesis of the antibiotic actinorhodin. The substrate hyphae of the fhaAB mutant also exhibited an unusual cording morphology. The results indicate that inactivation of FHA ‘brake’ proteins can potentially amplify the function of STPKs and, in this case, provide a means to overproduce antibiotics.
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Affiliation(s)
- Greg Jones
- Institute of Life Science, Swansea University, Singleton Park, Swansea SA28PP, UK
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Abstract
Bacteria can exist in metabolically inactive states that allow them to survive conditions that are not conducive for growth. Such dormant cells may sense when conditions have improved and re-initiate growth, lest they be outcompeted by their neighbours. Growing bacteria turn over and release large quantities of their cell walls into the environment. Drawing from recent work on the germination of Bacillus subtilis spores, we propose that many microorganisms exit dormancy in response to cell wall muropeptides.
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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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Understanding the role of PknJ in Mycobacterium tuberculosis: biochemical characterization and identification of novel substrate pyruvate kinase A. PLoS One 2010; 5:e10772. [PMID: 20520732 PMCID: PMC2875399 DOI: 10.1371/journal.pone.0010772] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 04/29/2010] [Indexed: 11/19/2022] Open
Abstract
Reversible protein phosphorylation is a prevalent signaling mechanism which modulates cellular metabolism in response to changing environmental conditions. In this study, we focus on previously uncharacterized Mycobacterium tuberculosis Ser/Thr protein kinase (STPK) PknJ, a putative transmembrane protein. PknJ is shown to possess autophosphorylation activity and is also found to be capable of carrying out phosphorylation on the artificial substrate myelin basic protein (MyBP). Previous studies have shown that the autophosphorylation activity of M. tuberculosis STPKs is dependent on the conserved residues in the activation loop. However, our results show that apart from the conventional conserved residues, additional residues in the activation loop may also play a crucial role in kinase activation. Further characterization of PknJ reveals that the kinase utilizes unusual ions (Ni2+, Co2+) as cofactors, thus hinting at a novel mechanism for PknJ activation. Additionally, as shown for other STPKs, we observe that PknJ possesses the capability to dimerize. In order to elucidate the signal transduction cascade emanating from PknJ, the M. tuberculosis membrane-associated protein fraction is treated with the active kinase and glycolytic enzyme Pyruvate kinase A (mtPykA) is identified as one of the potential substrates of PknJ. The phospholabel is found to be localized on serine and threonine residue(s), with Ser37 identified as one of the sites of phosphorylation. Since Pyk is known to catalyze the last step of glycolysis, our study shows that the fundamental pathways such as glycolysis can also be governed by STPK-mediated signaling.
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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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