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Fu X, Wan X, Memon AA, Fan XY, Sun Q, Chen H, Yao Y, Deng Z, Ma J, Ma W. Regulatory role of Mycobacterium tuberculosis MtrA on dormancy/resuscitation revealed by a novel target gene-mining strategy. Front Microbiol 2024; 15:1415554. [PMID: 38952446 PMCID: PMC11215152 DOI: 10.3389/fmicb.2024.1415554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 05/28/2024] [Indexed: 07/03/2024] Open
Abstract
Introduction The unique dormancy of Mycobacterium tuberculosis plays a significant role in the major clinical treatment challenge of tuberculosis, such as its long treatment cycle, antibiotic resistance, immune escape, and high latent infection rate. Methods To determine the function of MtrA, the only essential response regulator, one strategy was developed to establish its regulatory network according to high-quality genome-wide binding sites. Results and discussion The complex modulation mechanisms were implied by the strong bias distribution of MtrA binding sites in the noncoding regions, and 32.7% of the binding sites were located inside the target genes. The functions of 288 potential MtrA target genes predicted according to 294 confirmed binding sites were highly diverse, and DNA replication and damage repair, lipid metabolism, cell wall component biosynthesis, cell wall assembly, and cell division were the predominant pathways. Among the 53 pathways shared between dormancy/resuscitation and persistence, which accounted for 81.5% and 93.0% of the total number of pathways, respectively, MtrA regulatory genes were identified not only in 73.6% of their mutual pathways, but also in 75.4% of the pathways related to dormancy/resuscitation and persistence respectively. These results suggested the pivotal roles of MtrA in regulating dormancy/resuscitation and the apparent relationship between dormancy/resuscitation and persistence. Furthermore, the finding that 32.6% of the MtrA regulons were essential in vivo and/or in vitro for M. tuberculosis provided new insight into its indispensability. The findings mentioned above indicated that MtrA is a novel promising therapeutic target for tuberculosis treatment since the crucial function of MtrA may be a point of weakness for M. tuberculosis.
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Affiliation(s)
- Xiang Fu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoyu Wan
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Shanghai, China
| | - Aadil Ahmed Memon
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiao-Yong Fan
- Shanghai Public Health Clinical Center, Shanghai Institute of Infectious Diseases and Biosecurity, Fudan University, Shanghai, China
| | - Qiuhong Sun
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Shanghai, China
| | - Haifeng Chen
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yufeng Yao
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jian Ma
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Shanghai, China
| | - Wei Ma
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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Xie H, Ruan JY, Bu QT, Li YP, Su YT, Zhao QW, Du YL, Li YQ. Transcriptional regulation of the fidaxomicin gene cluster and cellular development in Actinoplanes deccanensis YP-1 by the pleiotropic regulator MtrA. Microbiol Spectr 2023; 11:e0270223. [PMID: 37966201 PMCID: PMC10714768 DOI: 10.1128/spectrum.02702-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/06/2023] [Indexed: 11/16/2023] Open
Abstract
IMPORTANCE Cascade regulation networks are almost present in various kinds of microorganisms, but locating and systematically elucidating specific pleiotropic regulators related to a certain gene cluster can be a tricky problem. Here, based on the promoter of the fidaxomicin pathway-specific regulator FadR1, we utilized a "DNA to Proteins" affinity purification method and captured a global regulator MtrA, which positively regulates fidaxomicin biosynthesis. In the mtrA overexpressed strain, the production of fidaxomicin was improved by 37% compared to the native strain. Then, we combined the "Protein to DNAs" affinity purification method (DAP-seq) with the results of RNA-seq and systematically elucidated the primary and secondary metabolic processes in which MtrA directly or indirectly participates. Thus, our work brought up a new way to improve fidaxomicin production from the perspective of global regulation and analyzed the regulatory mechanism of MtrA. Meanwhile, we provided a novel methodology for the research of cascade regulation networks and vital secondary metabolites.
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Affiliation(s)
- Huang Xie
- First Affiliated Hospital and Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Institute of Pharmaceutical Biotechnology, Hangzhou, China
| | - Jing-Yi Ruan
- First Affiliated Hospital and Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Institute of Pharmaceutical Biotechnology, Hangzhou, China
| | - Qing-Ting Bu
- First Affiliated Hospital and Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Institute of Pharmaceutical Biotechnology, Hangzhou, China
| | - Yue-Ping Li
- First Affiliated Hospital and Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Institute of Pharmaceutical Biotechnology, Hangzhou, China
| | - Yi-Ting Su
- First Affiliated Hospital and Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Institute of Pharmaceutical Biotechnology, Hangzhou, China
| | - Qing-Wei Zhao
- First Affiliated Hospital and Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi-Ling Du
- First Affiliated Hospital and Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Institute of Pharmaceutical Biotechnology, Hangzhou, China
| | - Yong-Quan Li
- First Affiliated Hospital and Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Institute of Pharmaceutical Biotechnology, Hangzhou, China
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3
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Peterson EJR, Brooks AN, Reiss DJ, Kaur A, Do J, Pan M, Wu WJ, Morrison R, Srinivas V, Carter W, Arrieta-Ortiz ML, Ruiz RA, Bhatt A, Baliga NS. MtrA modulates Mycobacterium tuberculosis cell division in host microenvironments to mediate intrinsic resistance and drug tolerance. Cell Rep 2023; 42:112875. [PMID: 37542718 PMCID: PMC10480492 DOI: 10.1016/j.celrep.2023.112875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 04/21/2023] [Accepted: 07/11/2023] [Indexed: 08/07/2023] Open
Abstract
The success of Mycobacterium tuberculosis (Mtb) is largely attributed to its ability to physiologically adapt and withstand diverse localized stresses within host microenvironments. Here, we present a data-driven model (EGRIN 2.0) that captures the dynamic interplay of environmental cues and genome-encoded regulatory programs in Mtb. Analysis of EGRIN 2.0 shows how modulation of the MtrAB two-component signaling system tunes Mtb growth in response to related host microenvironmental cues. Disruption of MtrAB by tunable CRISPR interference confirms that the signaling system regulates multiple peptidoglycan hydrolases, among other targets, that are important for cell division. Further, MtrA decreases the effectiveness of antibiotics by mechanisms of both intrinsic resistance and drug tolerance. Together, the model-enabled dissection of complex MtrA regulation highlights its importance as a drug target and illustrates how EGRIN 2.0 facilitates discovery and mechanistic characterization of Mtb adaptation to specific host microenvironments within the host.
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Affiliation(s)
| | | | - David J Reiss
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Amardeep Kaur
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Julie Do
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Min Pan
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Wei-Ju Wu
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Robert Morrison
- Laboratory of Malaria, Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | | | - Warren Carter
- Institute for Systems Biology, Seattle, WA 98109, USA
| | | | - Rene A Ruiz
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Apoorva Bhatt
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Nitin S Baliga
- Institute for Systems Biology, Seattle, WA 98109, USA; Departments of Biology and Microbiology, University of Washington, Seattle, WA 98195, USA; Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA; Lawrence Berkeley National Lab, Berkeley, CA 94720, USA.
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4
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Bhattarai S, Marsh L, Knight K, Ali L, Gomez A, Sunderhaus A, Abdel Aziz MH. NH125 Sensitizes Staphylococcus aureus to Cell Wall-Targeting Antibiotics through the Inhibition of the VraS Sensor Histidine Kinase. Microbiol Spectr 2023; 11:e0486122. [PMID: 37227302 PMCID: PMC10269531 DOI: 10.1128/spectrum.04861-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 05/09/2023] [Indexed: 05/26/2023] Open
Abstract
Staphylococcus aureus utilizes the two-component regulatory system VraSR to receive and relay environmental stress signals, and it is implicated in the development of bacterial resistance to several antibiotics through the upregulation of cell wall synthesis. VraS inhibition was shown to extend or restore the efficacy of several clinically used antibiotics. In this work, we study the enzymatic activity of the VraS intracellular domain (GST-VraS) to determine the kinetic parameters of the ATPase reaction and characterize the inhibition of NH125 under in vitro and microbiological settings. The rate of the autophosphorylation reaction was determined at different GST-VraS concentrations (0.95 to 9.49 μM) and temperatures (22 to 40°C) as well as in the presence of different divalent cations. The activity and inhibition by NH125, which is a known kinase inhibitor, were assessed in the presence and absence of the binding partner, VraR. The effects of inhibition on the bacterial growth kinetics and gene expression levels were determined. The GST-VraS rate of autophosphorylation increases with temperature and with the addition of VraR, with magnesium being the preferred divalent cation for the metal-ATP substrate complex. The mechanism of inhibition of NH125 was noncompetitive in nature and was attenuated in the presence of VraR. The addition of NH125 in the presence of sublethal doses of the cell wall-targeting antibiotics carbenicillin and vancomycin led to the complete abrogation of Staphylococcus aureus Newman strain growth and significantly decreased the gene expression levels of pbpB, blaZ, and vraSR in the presence of the antibiotics. IMPORTANCE This work characterizes the activity and inhibition of VraS, which is a key histidine kinase in a bacterial two-component system that is involved in Staphylococcus aureus antibiotic resistance. The results show the effect of temperature, divalent ions, and VraR on the activity and the kinetic parameters of ATP binding. The value of the KM of ATP is vital in designing screening assays to discover potent and effective VraS inhibitors with high translational potential. We report the ability of NH125 to inhibit VraS in vitro in a noncompetitive manner and investigate its effect on gene expression and bacterial growth kinetics in the presence and absence of cell wall-targeting antibiotics. NH125 effectively potentiated the effects of the antibiotics on bacterial growth and altered the expression of the genes that are regulated by VraS and are involved in mounting a resistance to antibiotics.
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Affiliation(s)
- Shrijan Bhattarai
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
| | - Lane Marsh
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
| | - Kelsey Knight
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
| | - Liaqat Ali
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
| | - Antonio Gomez
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
| | - Allison Sunderhaus
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
| | - May H. Abdel Aziz
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
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The Bacterial MtrAB Two-Component System Regulates the Cell Wall Homeostasis Responding to Environmental Alkaline Stress. Microbiol Spectr 2022; 10:e0231122. [PMID: 36073914 PMCID: PMC9602371 DOI: 10.1128/spectrum.02311-22] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Throughout the course of evolution, bacteria have developed signal transduction tools such as two-component systems (TCSs) to meet their demands to thrive even under the most challenging environmental conditions. One TCS called MtrAB is commonly found in Actinobacteria and is implicated in cell wall metabolism, osmoprotection, cell proliferation, antigen secretion, and biosynthesis of secondary metabolites. However, precisely how the MtrAB TCS regulates the bacterial responses to external environments remains unclear. Here, we report that the MtrAB TCS regulates the cell envelope response of alkali-tolerant bacterium Dietzia sp. strain DQ12-45-1b to extreme alkaline stimuli. We found that under alkaline conditions, an mtrAB mutant exhibited both reduced growth and abnormal morphology compared to the wild-type strain. Electrophoretic mobility shift assay analysis showed that MtrA binds the promoter of the mraZ gene critical for cell wall homeostasis, suggesting that MtrA directly controls transcription of this regulator. In conclusion, our findings demonstrate that MtrAB TCS is involved in controlling the bacterial response to alkaline stimuli by regulating the expression of the cell wall homeostasis regulator MraZ in Dietzia sp. DQ12-45-1b, providing novel details critical for a mechanistic understanding of how cell wall homeostasis is controlled. IMPORTANCE Microorganisms can be found in most extreme environments, and they have to adapt to a wide range of environmental stresses. The two-component systems (TCSs) found in bacteria detect environmental stimuli and regulate physiological pathways for survival. The MtrAB TCS conserved in Corynebacterineae is critical for maintaining the metabolism of the cell wall components that protects bacteria from diverse environmental stresses. However, how the MtrAB TCS regulates cell wall homeostasis and adaptation under stress conditions is unclear. Here, we report that the MtrAB TCS in Dietzia sp. DQ12-45-1b plays a critical role in alkaline resistance by modulating the cell wall homeostasis through the MtrAB-MraZ pathway. Thus, our work provides a novel regulatory pathway used by bacteria for adaptation and survival under extreme alkaline stresses.
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The Roles of the Two-Component System, MtrAB, in Response to Diverse Cell Envelope Stresses in Dietzia sp. DQ12-45-1b. Appl Environ Microbiol 2022; 88:e0133722. [PMID: 36190258 PMCID: PMC9599347 DOI: 10.1128/aem.01337-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Two-component systems (TCSs) act as common regulatory systems allowing bacteria to detect and respond to multiple environmental stimuli, including cell envelope stress. The MtrAB TCS of Actinobacteria is critical for cell wall homeostasis, cell proliferation, osmoprotection, and antibiotic resistance, and thus is found to be highly conserved across this phylum. However, how precisely the MtrAB TCS regulates cellular homeostasis in response to environmental stress remains unclear. Here, we show that the MtrAB TCS plays an important role in the tolerance to different types of cell envelope stresses, including environmental stresses (i.e., oxidative stress, lysozyme, SDS, osmotic pressure, and alkaline pH stresses) and envelope-targeting antibiotics (i.e., isoniazid, ethambutol, glycopeptide, and β-lactam antibiotics) in Dietzia sp. DQ12-45-1b. An mtrAB mutant strain exhibited slower growth compared to the wild-type strain and was characterized by abnormal cell shapes when exposed to various environmental stresses. Moreover, deletion of mtrAB resulted in decreased resistance to isoniazid, ethambutol, and β-lactam antibiotics. Further, Cleavage under targets and tagmentation sequencing (CUT&Tag-seq) and electrophoretic mobility shift assays (EMSAs) revealed that MtrA binds the promoters of genes involved in peptidoglycan biosynthesis (ldtB, ldtA, murJ), hydrolysis (GJR88_03483, GJR88_4713), and cell division (ftsE). Together, our findings demonstrated that the MtrAB TCS is essential for the survival of Dietzia sp. DQ12-45-1b under various cell envelope stresses, primarily by controlling multiple downstream cellular pathways. Our work suggests that TCSs act as global sensors and regulators in maintaining cellular homeostasis, such as during episodes of various environmental stresses. The present study should shed light on the understanding of mechanisms for bacterial adaptivity to extreme environments. IMPORTANCE The multilayered cell envelope is the first line of bacterial defense against various extreme environments. Bacteria utilize a large number of sensing and regulatory systems to maintain cell envelope homeostasis under multiple stress conditions. The two-component system (TCS) is the main sensing and responding apparatus for environmental adaptation. The MtrAB TCS highly conserved in Actinobacteria is critical for cell wall homeostasis, cell proliferation, osmoprotection, and antibiotic resistance. However, how MtrAB works with regard to signals impacting changes to the cell envelope is not fully understood. Here, we found that in the Actinobacterium Dietzia sp. DQ12-45-1b, a TCS named MtrAB is pivotal for ensuring normal cell growth as well as maintaining proper cell morphology in response to various cell envelope stresses, namely, by regulating the expression of cell envelope-related genes. Our findings should greatly advance our understanding of the adaptive mechanisms responsible for maintaining cell integrity in times of sustained environmental shocks.
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7
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Mutation of MtrA at the Predicted Phosphorylation Site Abrogates Its Role as a Global Regulator in Streptomyces venezuelae. Microbiol Spectr 2022; 10:e0213121. [PMID: 35293797 PMCID: PMC9045223 DOI: 10.1128/spectrum.02131-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The global regulator MtrA controls development and primary and secondary metabolism in Streptomyces species. However, residues critical for its function have not yet been characterized. In this study, we identified residue D53 as the potential phosphorylation site of MtrA from Streptomyces venezuelae, a model Streptomyces strain. MtrA variants with amino acid substitutions at the D53 site were generated, and the effects of these substitutions were evaluated in vitro and in vivo. We showed that, although substitutions at D53 did not alter MtrA's secondary structure, the MtrA D53 protein variants lost the ability to bind known MtrA recognition sequences (MtrA sites) in electrophoretic mobility shift assays. Complementation of the ΔmtrA strain with MtrA D53 protein variants did not affect overall strain growth. However, in comparison to the wild-type strain, chloramphenicol and jadomycin production were aberrant in the D53 variant strains, with levels similar to the levels in the ΔmtrA strain. Transcriptional analysis showed that the expression patterns of genes were also similar in the ΔmtrA strain and the D53 variant strains. Although the D53 protein variants and wild-type MtrA were produced at similar levels in S. venezuelae, chromatin immunoprecipitation-quantitative PCR results indicated that replacing the D53 residue rendered the altered proteins unable to bind MtrA sites in vivo, including MtrA sites that regulate genes involved in nitrogen metabolism and in chloramphenicol and jadomycin biosynthesis. In conclusion, our study demonstrates that the predicted phosphorylation site D53 is critical for the role of MtrA in regulation and suggests that MtrA functions in a phosphorylated form in the genus Streptomyces. IMPORTANCE Although phosphorylation has been shown to be essential for the activation of many response regulator proteins of two-component systems, the role of the phosphorylation site in the function of the global regulator MtrA in the genus Streptomyces has not been reported. In this study, we generated Streptomyces mutants that had amino acid substitutions at the predicted phosphorylation site of MtrA, and the effects of the substitutions were investigated by comparing the phenotypes of the resulting strains and their gene expression patterns with those of the wild-type strain and an MtrA deletion mutant. The ability of the altered proteins to bind known promoter targets in vitro was also evaluated. Our analyses showed that the predicted phosphorylation site D53 is critical for MtrA binding in vitro and for the normal functioning of MtrA in vivo. These studies further demonstrate the importance of MtrA as a global regulator in the genus Streptomyces.
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Singh KK, Athira PJ, Bhardwaj N, Singh DP, Watson U, Saini DK. Acetylation of Response Regulator Protein MtrA in M. tuberculosis Regulates Its Repressor Activity. Front Microbiol 2021; 11:516315. [PMID: 33519719 PMCID: PMC7843721 DOI: 10.3389/fmicb.2020.516315] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 12/17/2020] [Indexed: 11/13/2022] Open
Abstract
MtrA is an essential response regulator (RR) protein in M. tuberculosis, and its activity is modulated after phosphorylation from its sensor kinase MtrB. Interestingly, many regulatory effects of MtrA have been reported to be independent of its phosphorylation, thereby suggesting alternate mechanisms of regulation of the MtrAB two-component system in M. tuberculosis. Here, we show that RR MtrA undergoes non-enzymatic acetylation through acetyl phosphate, modulating its activities independent of its phosphorylation status. Acetylated MtrA shows increased phosphorylation and enhanced interaction with SK MtrB assessed by phosphotransfer assays and FRET analysis. We also observed that acetylated MtrA loses its DNA-binding ability on gene targets that are otherwise enhanced by phosphorylation. More interestingly, acetylation is the dominant post-translational modification, overriding the effect of phosphorylation. Evaluation of the impact of MtrA and its lysine mutant overexpression on the growth of H37Ra bacteria under different conditions along with the infection studies on alveolar epithelial cells further strengthens the importance of acetylated MtrA protein in regulating the growth of M. tuberculosis. Overall, we show that both acetylation and phosphorylation regulate the activities of RR MtrA on different target genomic regions. We propose here that, although phosphorylation-dependent binding of MtrA drives its repressor activity on oriC and rpf, acetylation of MtrA turns this off and facilitates division in mycobacteria. Our findings, thus, reveal a more complex regulatory role of RR proteins in which multiple post-translational modifications regulate the activities at the levels of interaction with SK and the target gene expression.
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Affiliation(s)
- Krishna Kumar Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
| | - P J Athira
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
| | - Neerupma Bhardwaj
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, India
| | - Devendra Pratap Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
| | - Uchenna Watson
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India.,Department of Studies in Zoology, University of Mysore, Mysore, India
| | - Deepak Kumar Saini
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India.,Centre for Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India
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Sarva K, Satsangi AT, Plocinska R, Madiraju M, Rajagopalan M. Two-component kinase TrcS complements Mycobacterium smegmatis mtrB kinase mutant. Tuberculosis (Edinb) 2019; 116S:S107-S113. [PMID: 31088763 DOI: 10.1016/j.tube.2019.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 11/21/2018] [Indexed: 10/26/2022]
Abstract
MtrAB is one of the important two-component regulatory systems (2CRS) in mycobacteria and consists of MtrB sensor kinase and MtrA response regulator. Mycobacterium smegmatis mtrB mutant is filamentous and shows defects in cell division, cell shape and optimal expression of the MtrA-regulon. In an effort to identify M. tuberculosis sensor kinases that work with MtrA and/or bypass the need for MtrB, we attempted to overexpress other M. tuberculosis sensor kinases in M. smegmatis mtrB background and reverse the mtrB phenotype. Overexpression of trcS kinase, but not nine others tested, reversed the mtrB mutant phenotype including the expression of the MtrA-regulon. However, the overexpression of trcS kinase did not reverse the mutant phenotype of a mtrA mutant. Bacterial-two hybrid assays revealed that the TrcS kinase interacts with both MtrB kinase and the response regulator MtrA. Recombinant TrcS protein exhibits autophosphorylation and transphosphorylation of its cognate response regulator TrcR, and MtrA. Together, these results support a model involving cross-talk between the MtrAB and TrcRS two-component systems.
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Affiliation(s)
- Krishna Sarva
- The University of Health Science Center @ Tyler, Tyler, TX, 75708, USA
| | | | - Renata Plocinska
- The University of Health Science Center @ Tyler, Tyler, TX, 75708, USA
| | - Murty Madiraju
- The University of Health Science Center @ Tyler, Tyler, TX, 75708, USA
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10
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Li X, Lv X, Lin Y, Zhen J, Ruan C, Duan W, Li Y, Xie J. Role of two-component regulatory systems in intracellular survival of Mycobacterium tuberculosis. J Cell Biochem 2019; 120:12197-12207. [PMID: 31026098 DOI: 10.1002/jcb.28792] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/11/2019] [Accepted: 01/14/2019] [Indexed: 11/06/2022]
Abstract
The typical two-component regulatory systems (TCSs), consisting of response regulator and histidine kinase, play a central role in survival of pathogenic bacteria under stress conditions such as nutrient starvation, hypoxia, and nitrosative stress. A total of 11 complete paired two-component regulatory systems have been found in Mycobacterium tuberculosis, including a few isolated kinase and regulatory genes. Increasing evidence has shown that TCSs are closely associated with multiple physiological process like intracellular persistence, pathogenicity, and metabolism. This review gives the two-component signal transduction systems in M. tuberculosis and their signal transduction roles in adaption to the environment.
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Affiliation(s)
- Xue Li
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Xi Lv
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Yanping Lin
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Junfeng Zhen
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Cao Ruan
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Wei Duan
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Yue Li
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Jianping Xie
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
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Gorla P, Plocinska R, Sarva K, Satsangi AT, Pandeeti E, Donnelly R, Dziadek J, Rajagopalan M, Madiraju MV. MtrA Response Regulator Controls Cell Division and Cell Wall Metabolism and Affects Susceptibility of Mycobacteria to the First Line Antituberculosis Drugs. Front Microbiol 2018; 9:2839. [PMID: 30532747 PMCID: PMC6265350 DOI: 10.3389/fmicb.2018.02839] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/05/2018] [Indexed: 11/25/2022] Open
Abstract
The biological processes regulated by the essential response regulator MtrA and the growth conditions promoting its activation in Mycobacterium tuberculosis, a slow grower and pathogen, are largely unknown. Here, using a gain-of-function mutant, MtrAY 102C, which functions in the absence of the cognate MtrB sensor kinase, we show that the MtrA regulon includes several genes involved in the processes of cell division and cell wall metabolism. The expression of selected MtrA targets and intracellular MtrA levels were compromised under replication arrest induced by genetic manipulation and under stress conditions caused by toxic radicals. The loss of the mtrA gene in M. smegmatis, a rapid grower and non-pathogen, produced filamentous cells with branches and bulges, indicating defects in cell division and cell shape. The ΔmtrA mutant was sensitized to rifampicin and vancomycin and became more resistant to isoniazid, the first line antituberculosis drug. Our data are consistent with the proposal that MtrA controls the optimal cell division, cell wall integrity, and susceptibility to some antimycobacterial drugs.
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Affiliation(s)
- Purushotham Gorla
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Renata Plocinska
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Krishna Sarva
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Akash T Satsangi
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Emmanuel Pandeeti
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Robert Donnelly
- Department of Pathology and Laboratory Medicine, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Jaroslaw Dziadek
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Malini Rajagopalan
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
| | - Murty V Madiraju
- Biomedical Research, The University of Texas Health Science Center, Tyler, TX, United States
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12
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Kou X, Liu X, Liu Y, Li C, Liu M, Jiang L. Backbone resonance assignment of the response regulator protein PhoB NF20D from Escherichia coli. BIOMOLECULAR NMR ASSIGNMENTS 2018; 12:133-137. [PMID: 29299752 DOI: 10.1007/s12104-017-9795-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/27/2017] [Indexed: 06/07/2023]
Abstract
PhoB is a response regulator of the PhoR/PhoB two-component signal transduction system that is involved in the regulation of the phosphate (Pho) regulon of Escherichia coli. PhoB has two domains, receiver domain and effector domain. The receiver domain can be phosphorylated by its cognate histidine kinase PhoR and the phosphorylation induces conformational changes of the full length protein of PhoB that promote the DNA binding and transcription. Three-dimensional crystal structures of PhoB receiver domain (PhoBN) have been solved under apo or BeF3- (a phosphoryl analog) binding forms and it has been found that PhoBN is dimerized in both situations. However, we have found that the apo form of PhoBN has multiple conformational changes in solution that is hard to be distinguished by using NMR spectroscopy, while the mutagenesis of F20D PhoBN gives homogeneous dispersed signals in HSQC spectrum indicating a relatively uniform conformation. Meanwhile the F20D mutant has the same phosphorylation activity as the wild type protein. Here we report the backbone assignment of PhoBNF20D mutant. The chemical shift (HN, N, CO, Cα and Cβ) analysis shows that the predicted regions of secondary structure are in good agreement with those observed in the crystal structure of apo PhoBN. Therefore, the backbone chemical shifts assignment of PhoBNF20D mutant would be useful for studying the structure and dynamics of PhoB receiver domain and it has significance for explaining the mechanism of phosphorylation in TCSs.
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Affiliation(s)
- Xinhui Kou
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan, 430071, China
- Graduate University of Chinese Academy of Science, 19A Yuquanlu, Beijing, 100049, China
| | - Xinghong Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan, 430071, China
- Graduate University of Chinese Academy of Science, 19A Yuquanlu, Beijing, 100049, China
| | - Yixiang Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan, 430071, China
| | - Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan, 430071, China
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan, 430071, China
| | - Ling Jiang
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan, 430071, China.
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13
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Abstract
Two-component regulatory systems (2CRSs) are widely used by bacteria to sense and respond to environmental stimuli with coordinated changes in gene expression. Systems are normally comprised of a sensory kinase protein that activates a transcriptional regulator by phosphorylation. Mycobacteria have few 2CRSs, but they are of key importance for bacterial survival and play important roles in pathogenicity. Mycobacterium tuberculosis has 12 paired two-component regulatory systems (which include a system with two regulators and one sensor, and a split sensor system), as well as four orphan regulators. Several systems are involved in virulence, and disruption of different systems leads to attenuation or hypervirulence. PhoPR plays a major role in regulating cell wall composition, and its inactivation results in sufficient attenuation of M. tuberculosis that deletion strains are live vaccine candidates. MprAB controls the stress response and is required for persistent infections. SenX3-RegX3 is required for control of aerobic respiration and phosphate uptake, and PrrAB is required for adaptation to intracellular infection. MtrAB is an essential system that controls DNA replication and cell division. The remaining systems (KdpDE, NarL, TrcRS, TcrXY, TcrA, PdtaRS, and four orphan regulators) are less well understood. The structure and binding motifs for several regulators have been characterized, revealing variations in function and operation. The sensors are less well characterized, and stimuli for many remain to be confirmed. This chapter reviews our current understanding of the role of two-component systems in mycobacteria, in particular M. tuberculosis.
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14
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Purushotham G, Sarva KB, Blaszczyk E, Rajagopalan M, Madiraju MV. Mycobacterium tuberculosis oriC sequestration by MtrA response regulator. Mol Microbiol 2015. [PMID: 26207528 DOI: 10.1111/mmi.13144] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The regulators of Mycobacterium tuberculosis DNA replication are largely unknown. Here, we demonstrate that in synchronously replicating M. tuberculosis, MtrA access to origin of replication (oriC) is enriched in the post-replication (D) period. The increased oriC binding results from elevated MtrA phosphorylation (MtrA∼P) as evidenced by reduced expression of dnaN, dnaA and increased expression of select cell division targets. Overproduction of gain-of-function MtrAY102C advanced the MtrA oriC access to the C period, reduced dnaA and dnaN expression, interfered with replication synchrony and compromised cell division. Overproduction of wild-type (MtrA+) or phosphorylation-defective MtrAD56N did not promote oriC access in the C period, nor affected cell cycle progression. MtrA interacts with DnaA signaling a possibility that DnaA helps load MtrA on oriC. Therefore, oriC sequestration by MtrA∼P in the D period may normally serve to prevent untimely initiations and that DnaA-MtrA interactions may facilitate regulated oriC replication. Finally, despite the near sequence identity of MtrA in M. smegmatis and M. tuberculosis, the M. smegmatis oriC is not MtrA-target. We conclude that M. tuberculosis oriC has evolved to be regulated by MtrA and that cell cycle progression in this organisms are governed, at least in part, by oscillations in the MtrA∼P levels.
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Affiliation(s)
- Gorla Purushotham
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
| | - Krishna B Sarva
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
| | - Ewelina Blaszczyk
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
| | - Malini Rajagopalan
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
| | - Murty V Madiraju
- Biomedical Research, The University of Health Science Center at Tyler, Tyler, TX, 75708, USA
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15
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Sharma AK, Chatterjee A, Gupta S, Banerjee R, Mandal S, Mukhopadhyay J, Basu J, Kundu M. MtrA, an essential response regulator of the MtrAB two-component system, regulates the transcription of resuscitation-promoting factor B of Mycobacterium tuberculosis. MICROBIOLOGY-SGM 2015; 161:1271-81. [PMID: 25833257 DOI: 10.1099/mic.0.000087] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The resuscitation-promoting factors of Mycobacterium tuberculosis are hydrolytic enzymes, which are required for resuscitation of dormant cells. RpfB, a peptidoglycan remodelling enzyme similar to the lytic transglycosylase of Escherichia coli, is required for reactivation of M. tuberculosis from chronic infection in vivo, underscoring the need to understand its transcriptional regulation. Here, we identified the transcriptional and translational start points of rpfB, and suggested from rpf promoter-driven GFP expression and in vitro transcription assays that its transcription possibly occurs in a SigB-dependent manner. We further demonstrated that rpfB transcription is regulated by MtrA - the response regulator of the essential two-component system MtrAB. Association of MtrA with the rpfB promoter region in vivo was confirmed by chromatin immunoprecipitation analysis. Electrophoretic mobility shift assays (EMSAs) revealed a loose direct repeat sequence associated with MtrA binding. Binding of MtrA was enhanced upon phosphorylation. MtrA could be pulled down from lysates of M. tuberculosis using a biotinylated DNA fragment encompassing the MtrA-binding site on the rpfB promoter, confirming that MtrA binds to the rpfB promoter. Enhanced GFP fluorescence driven by the rpfB promoter, upon deletion of the MtrA-binding site, and repression of rpfB expression, upon overexpression of MtrA, suggested that MtrA functions as a repressor of rpfB transcription. This was corroborated by EMSAs showing diminished association of RNA polymerase (RNAP) with the rpfB promoter in the presence of MtrA. In vitro transcription assays confirmed that MtrA inhibits RNAP-driven rpfB transcription.
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Affiliation(s)
- Arun Kumar Sharma
- 1Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Ayan Chatterjee
- 1Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Shamba Gupta
- 1Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Rajdeep Banerjee
- 1Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Sukhendu Mandal
- 2Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata 700054, India
| | - Jayanta Mukhopadhyay
- 1Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Joyoti Basu
- 1Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Manikuntala Kundu
- 1Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
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16
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Donczew R, Makowski Ł, Jaworski P, Bezulska M, Nowaczyk M, Zakrzewska-Czerwińska J, Zawilak-Pawlik A. The atypical response regulator HP1021 controls formation of the Helicobacter pylori replication initiation complex. Mol Microbiol 2014; 95:297-312. [PMID: 25402746 DOI: 10.1111/mmi.12866] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2014] [Indexed: 12/15/2022]
Abstract
The replication of a bacterial chromosome is initiated by the DnaA protein, which binds to the specific chromosomal region oriC and unwinds duplex DNA within the DNA-unwinding element (DUE). The initiation is tightly regulated by many factors, which control either DnaA or oriC activity and ensure that the chromosome is duplicated only when the conditions favor the survival of daughter cells. The factors controlling oriC activity often belong to the protein families of two-component systems. Here, we found that Helicobacter pylori oriC activity is controlled by HP1021, a member of the atypical response regulator family. HP1021 protein specifically interacts with H. pylori oriC at HP1021 boxes (5'-TGTT[TA]C[TA]-3'), which overlap with three modules important for oriC function: DnaA boxes, the hypersensitivity (hs) region and the DUE. Consequently, HP1021 binding to oriC precludes DnaA-oriC interactions and inhibits DNA unwinding at the DUE. Thus, HP1021 constitutes a negative regulator of the H. pylori orisome assembly in vitro. Furthermore, HP1021 boxes were found upstream of at least 70 genes, including those encoding CagA and Fur proteins. We postulate that HP1021 might coordinate chromosome replication, and thus bacterial growth, with other cellular processes and conditions in the human stomach.
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Affiliation(s)
- Rafał Donczew
- Department of Microbiology, Polish Academy of Sciences, Institute of Immunology and Experimental Therapy, Weigla 12, Wrocław, 53-114, Poland
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17
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Satsangi AT, Pandeeti EP, Sarva K, Rajagopalan M, Madiraju MV. Mycobacterium tuberculosis MtrAY102C is a gain-of-function mutant that potentially acts as a constitutively active protein. Tuberculosis (Edinb) 2014; 93 Suppl:S28-32. [PMID: 24388645 DOI: 10.1016/s1472-9792(13)70007-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The MtrAB histidine-aspartate signal transduction of mycobacteria includes the response regulator MtrA and sensor kinase MtrB. We recently showed that Mycobacterium smegmatis ΔmtrB is filamentous, defective for cell division, cell shape maintenance and shows compromised MtrA target gene expression. Interestingly, overproduction of phosphorylation competent M. tuberculosis MtrAY102C reverses the ΔmtrB mutant phenotype, although the genetic basis of phenotype reversal is unknown. Here we show that introduction of D56N mutation in MtrAY102C completely abolished its phosphorylation potential yet the double mutant protein retained a partial ability to reverse the mtrB mutant phenotype indicating that phosphorylation activity is not necessary for the function of MtrAY102C. The phosphorylation-defective MtrAD56N-Y102C protein bound its target promoters ripA and fbpB efficiently. Together, these results support a hypothesis that the gain-of-function phenotype of MtrAY102C is in part due to its ability to function as a constitutively active protein in the absence of phosphorylation.
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Affiliation(s)
- Akash T Satsangi
- Biomedical Research, The University of Texas Health Science Center @ Tyler, 11937 U.S. Hwy@ 271, Tyler, TX- 75708-3154, USA
| | - Emmanuel P Pandeeti
- Biomedical Research, The University of Texas Health Science Center @ Tyler, 11937 U.S. Hwy@ 271, Tyler, TX- 75708-3154, USA
| | - Krishna Sarva
- Biomedical Research, The University of Texas Health Science Center @ Tyler, 11937 U.S. Hwy@ 271, Tyler, TX- 75708-3154, USA
| | - Malini Rajagopalan
- Biomedical Research, The University of Texas Health Science Center @ Tyler, 11937 U.S. Hwy@ 271, Tyler, TX- 75708-3154, USA
| | - Murty V Madiraju
- Biomedical Research, The University of Texas Health Science Center @ Tyler, 11937 U.S. Hwy@ 271, Tyler, TX- 75708-3154, USA.
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18
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Mycobacterium tuberculosis MtrB sensor kinase interactions with FtsI and Wag31 proteins reveal a role for MtrB distinct from that regulating MtrA activities. J Bacteriol 2014; 196:4120-9. [PMID: 25225272 DOI: 10.1128/jb.01795-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The septal association of Mycobacterium tuberculosis MtrB, the kinase partner of the MtrAB two-component signal transduction system, is necessary for the optimal expression of the MtrA regulon targets, including ripA, fbpB, and ftsI, which are involved in cell division and cell wall synthesis. Here, we show that MtrB, irrespective of its phosphorylation status, interacts with Wag31, whereas only phosphorylation-competent MtrB interacts with FtsI. We provide evidence that FtsI depletion compromises the MtrB septal assembly and MtrA regulon expression; likewise, the absence of MtrB compromises FtsI localization and, possibly, FtsI activity. We conclude from these results that FtsI and MtrB are codependent for their activities and that FtsI functions as a positive modulator of MtrB activation and MtrA regulon expression. In contrast to FtsI, Wag31 depletion does not affect MtrB septal assembly and MtrA regulon expression, whereas the loss of MtrB increased Wag31 localization and the levels of PknA/PknB (PknA/B) serine-threonine protein kinase-mediated Wag31 phosphorylation. Interestingly, we found that FtsI decreased levels of phosphorylated Wag31 (Wag31∼P) and that MtrB interacted with PknA/B. Overall, our results indicate that MtrB interactions with FtsI, Wag31, and PknA/B are required for its optimal localization, MtrA regulon expression, and phosphorylation of Wag31. Our results emphasize a new role for MtrB in cell division and cell wall synthesis distinct from that regulating the MtrA phosphorylation activities.
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19
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Plocinska R, Purushotham G, Sarva K, Vadrevu IS, Pandeeti EVP, Arora N, Plocinski P, Madiraju MV, Rajagopalan M. Septal localization of the Mycobacterium tuberculosis MtrB sensor kinase promotes MtrA regulon expression. J Biol Chem 2012; 287:23887-99. [PMID: 22610443 DOI: 10.1074/jbc.m112.346544] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanisms responsible for activation of the MtrAB two-component regulatory signal transduction system, which includes sensor kinase MtrB and response regulator MtrA, are unknown. Here, we show that an MtrB-GFP fusion protein localized to the cell membrane, the septa, and the poles in Mycobacterium tuberculosis and Mycobacterium smegmatis. This localization was independent of MtrB phosphorylation status but dependent upon the assembly of FtsZ, the initiator of cell division. The M. smegmatis mtrB mutant was filamentous, defective for cell division, and contained lysozyme-sensitive cell walls. The mtrB phenotype was complemented by either production of MtrB protein competent for phosphorylation or overproduction of MtrA(Y102C) and MtrA(D13A) mutant proteins exhibiting altered phosphorylation potential, indicating that either MtrB phosphorylation or MtrB independent expression of MtrA regulon genes, including those involved in cell wall processing, are necessary for regulated cell division. In partial support of this observation, we found that the essential cell wall hydrolase ripA is an MtrA target and that the expression of bona fide MtrA targets ripA, fbpB, and dnaA were compromised in the mtrB mutant and partially rescued upon MtrA(Y102C) and MtrA(D13A) overproduction. MtrB septal assembly was compromised upon FtsZ depletion and exposure of cells to mitomycin C, a DNA damaging agent, which interferes with FtsZ ring assembly. Expression of MtrA targets was also compromised under the above conditions, indicating that MtrB septal localization and MtrA regulon expression are linked. We propose that MtrB septal association is a necessary feature of MtrB activation that promotes MtrA phosphorylation and MtrA regulon expression.
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Affiliation(s)
- Renata Plocinska
- Biomedical Research, The University of Texas Health Science Center, Tyler, Texas 75708-3154, USA
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