1
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Kim SK, Orr MW, Turdiev H, Jenkins CC, Lormand JD, Myers TM, Burnim AA, Carter JA, Kung WC, Jiang X, Sondermann H, Winkler WC, Lee VT. Diribonuclease activity eliminates toxic diribonucleotide accumulation. Cell Rep 2024; 43:114759. [PMID: 39276351 DOI: 10.1016/j.celrep.2024.114759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 07/29/2024] [Accepted: 08/29/2024] [Indexed: 09/17/2024] Open
Abstract
RNA degradation is a central process required for transcriptional regulation. Eventually, this process degrades diribonucleotides into mononucleotides by specific diribonucleases. In Escherichia coli, oligoribonuclease (Orn) serves this function and is unique as the only essential exoribonuclease. Yet, related organisms, such as Pseudomonas aeruginosa, display a growth defect but are viable without Orn, contesting its essentiality. Here, we take advantage of P. aeruginosa orn mutants to screen for suppressors that restore colony morphology and identified yciV. Purified YciV (RNase AM) exhibits diribonuclease activity. While RNase AM is present in all γ-proteobacteria, phylogenetic analysis reveals differences that map to the active site. RNase AMPa expression in E. coli eliminates the necessity of orn. Together, these results show that diribonuclease activity prevents toxic diribonucleotide accumulation in γ-proteobacteria, suggesting that diribonucleotides may be utilized to monitor RNA degradation efficacy. Because higher eukaryotes encode Orn, these observations indicate a conserved mechanism for monitoring RNA degradation.
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Affiliation(s)
- Soo-Kyoung Kim
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD 20742, USA; Research Institute for Drug Development, Pusan National University, Busan 46241, South Korea
| | - Mona W Orr
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD 20742, USA
| | - Husan Turdiev
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD 20742, USA
| | - Conor C Jenkins
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD 20742, USA
| | - Justin D Lormand
- CSSB Centre for Structural Systems Biology, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Tanner M Myers
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD 20742, USA
| | | | - Jared A Carter
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD 20742, USA
| | - Warren C Kung
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD 20742, USA
| | - Xiaofang Jiang
- Intramural Research Program, NLM, NIH, Bethesda, MD 20894, USA
| | - Holger Sondermann
- CSSB Centre for Structural Systems Biology, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Wade C Winkler
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD 20742, USA
| | - Vincent T Lee
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD 20742, USA.
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2
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Zheng R, Wu R, Liu Y, Sun Z, Xue Z, Bagheri Y, Khajouei S, Mi L, Tian Q, Pho R, Liu Q, Siddiqui S, Ren K, You M. Multiplexed sequential imaging in living cells with orthogonal fluorogenic RNA aptamer/dye pairs. Nucleic Acids Res 2024; 52:e67. [PMID: 38922685 PMCID: PMC11347136 DOI: 10.1093/nar/gkae551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 06/01/2024] [Accepted: 06/14/2024] [Indexed: 06/28/2024] Open
Abstract
Detecting multiple targets in living cells is important in cell biology. However, multiplexed fluorescence imaging beyond two-to-three targets remains a technical challenge. Herein, we introduce a multiplexed imaging strategy, 'sequential Fluorogenic RNA Imaging-Enabled Sensor' (seqFRIES), which enables live-cell target detection via sequential rounds of imaging-and-stripping. In seqFRIES, multiple orthogonal fluorogenic RNA aptamers are genetically encoded inside cells, and then the corresponding cell membrane permeable dye molecules are added, imaged, and rapidly removed in consecutive detection cycles. As a proof-of-concept, we have identified in this study four fluorogenic RNA aptamer/dye pairs that can be used for highly orthogonal and multiplexed imaging in living bacterial and mammalian cells. After further optimizing the cellular fluorescence activation and deactivation kinetics of these RNA/dye pairs, the whole four-color semi-quantitative seqFRIES process can be completed in ∼20 min. Meanwhile, seqFRIES-mediated simultaneous detection of critical signalling molecules and mRNA targets was also achieved within individual living cells. We expect our validation of this new seqFRIES concept here will facilitate the further development and potential broad usage of these orthogonal fluorogenic RNA/dye pairs for multiplexed and dynamic live-cell imaging and cell biology studies.
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Affiliation(s)
- Ru Zheng
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Rigumula Wu
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Yuanchang Liu
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Zhining Sun
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Zhaolin Xue
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Yousef Bagheri
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Sima Khajouei
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Lan Mi
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Qian Tian
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Raymond Pho
- Department of Chemical Engineering, University of Massachusetts, Amherst, MA 01003, USA
| | - Qinge Liu
- Department of Chemistry, Mount Holyoke College, Holyoke, MA 01075, USA
| | - Sidrat Siddiqui
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Kewei Ren
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Mingxu You
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, MA 01003, USA
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3
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Schicketanz M, Petrová M, Rejman D, Sosio M, Donadio S, Zhang YE. Direct detection of stringent alarmones (pp)pGpp using malachite green. MICROBIAL CELL (GRAZ, AUSTRIA) 2024; 11:312-320. [PMID: 39119257 PMCID: PMC11307201 DOI: 10.15698/mic2024.08.834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 08/10/2024]
Abstract
The alarmone (p)ppGpp serves as the signalling molecule for the bacterial universal stringent response and plays a crucial role in bacterial virulence, persistence, and stress adaptation. Consequently, there is a significant focus on developing new drugs that target and modulate the levels of (p)ppGpp as a potential strategy for controlling bacterial infections. However, despite the availability of various methods for detecting (p)ppGpp, a simple and straightforward detection method is needed. In this study, we demonstrated that malachite green, a well-established compound used for phosphate detection, can directly detect (p)ppGpp and its analogues esp., pGpp. By utilizing malachite green, we identified three new inhibitors of the hydrolase activity of SpoT, one of the two RelA-SpoT homolog (RSH) proteins responsible for making and hydrolyzing (p)ppGpp in Escherichia coli. These findings highlight the convenience and practicality of malachite green, which can be widely employed in high-throughput studies to investigate (pp)pGpp in vitro and discover novel regulators of RSH proteins.
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Affiliation(s)
- Muriel Schicketanz
- Department of Biology, University of CopenhagenCopenhagen, DK-2200Denmark
| | - Magdalena Petrová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences v.v.iPragueCzech Republic
| | - Dominik Rejman
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences v.v.iPragueCzech Republic
| | | | | | - Yong Everett Zhang
- Department of Biology, University of CopenhagenCopenhagen, DK-2200Denmark
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4
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Chrenková A, Bisiak F, Brodersen DE. Breaking bad nucleotides: understanding the regulatory mechanisms of bacterial small alarmone hydrolases. Trends Microbiol 2024; 32:769-780. [PMID: 38262803 DOI: 10.1016/j.tim.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 12/27/2023] [Accepted: 12/29/2023] [Indexed: 01/25/2024]
Abstract
Guanosine tetra- and pentaphosphate nucleotides, (p)ppGpp, function as central secondary messengers and alarmones in bacterial cell biology, signalling a range of stress conditions, including nutrient starvation and exposure to cell-wall-targeting antibiotics, and are critical for survival. While activation of the stringent response and alarmone synthesis on starved ribosomes by members of the RSH (Rel) class of proteins is well understood, much less is known about how single-domain small alarmone synthetases (SASs) and their corresponding alarmone hydrolases, the small alarmone hydrolases (SAHs), are regulated and contribute to (p)ppGpp homeostasis. The substrate spectrum of these enzymes has recently been expanded to include hyperphosphorylated adenosine nucleotides, suggesting that they take part in a highly complex and interconnected signalling network. In this review, we provide an overview of our understanding of the SAHs and discuss their structure, function, regulation, and phylogeny.
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Affiliation(s)
- Adriana Chrenková
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000 Aarhus C, Denmark
| | - Francesco Bisiak
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000 Aarhus C, Denmark
| | - Ditlev E Brodersen
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000 Aarhus C, Denmark.
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Liu S, Fang Z, Li Y, Kang L, Cong H, Shen Y, Yu B. Four Kinds of Polymer Microspheres Prepared by the Seed Swelling Method Used to Purify the Industrial Production of Phytol. J Chromatogr Sci 2024; 62:508-514. [PMID: 36752419 DOI: 10.1093/chromsci/bmad006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 12/11/2022] [Accepted: 01/13/2023] [Indexed: 02/09/2023]
Abstract
Four monodisperse porous polymer microspheres were successfully prepared by seed emulsion polymerization and used as stationary phases for HPLC and preparative high-performance liquid chromatography (Prep-HPLC). All four polymer microspheres(polystyrene-polystyrene (PS-PS), polystyrene-poly(glycidyl methylate) (PS-PGMA), polystyrene-poly(methyl methylate) and poly(glycidyl methylate)-poly(glycidyl methylate) were used for filling HPLC empty columns. According to the analysis results of the HPLC column, PS-PS and PS-PGMA microspheres were screened out as the stationary phase of Prep-HPLC. The industrial-grade phytol was successfully separated and purified, and the purity of the final phytol was as high as 99%. The two types of polymer microspheres have been applied to industrial-grade phytol purification and have been used in factories.
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Affiliation(s)
- Shixiang Liu
- College of Chemistry and Chemical Engineering, College of Materials Science and Engineering, Institute of Biomedical Materials and Engineering, Qingdao University, Qingdao 266071, China
| | - Zhipeng Fang
- College of Chemistry and Chemical Engineering, College of Materials Science and Engineering, Institute of Biomedical Materials and Engineering, Qingdao University, Qingdao 266071, China
| | - Yanan Li
- College of Chemistry and Chemical Engineering, College of Materials Science and Engineering, Institute of Biomedical Materials and Engineering, Qingdao University, Qingdao 266071, China
| | - Linlin Kang
- College of Chemistry and Chemical Engineering, College of Materials Science and Engineering, Institute of Biomedical Materials and Engineering, Qingdao University, Qingdao 266071, China
| | - Hailin Cong
- College of Chemistry and Chemical Engineering, College of Materials Science and Engineering, Institute of Biomedical Materials and Engineering, Qingdao University, Qingdao 266071, China
- State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao 266071, China
| | - Youqing Shen
- College of Chemistry and Chemical Engineering, College of Materials Science and Engineering, Institute of Biomedical Materials and Engineering, Qingdao University, Qingdao 266071, China
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Center for Bionanoengineering, and Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Bing Yu
- College of Chemistry and Chemical Engineering, College of Materials Science and Engineering, Institute of Biomedical Materials and Engineering, Qingdao University, Qingdao 266071, China
- State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao 266071, China
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6
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Scharf A, La-Rostami F, Illarionov BA, Nemes V, Feldmann AM, Höft LS, Lösel H, Bacher A, Fischer M. Systematic Analysis of the Effect of Genomic Knock-Out of Non-Essential Promiscuous HAD-Like Phosphatases YcsE, YitU and YwtE on Flavin and Adenylate Content in Bacillus Subtilis. Chembiochem 2024; 25:e202400165. [PMID: 38616163 DOI: 10.1002/cbic.202400165] [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: 02/22/2024] [Revised: 04/05/2024] [Accepted: 04/09/2024] [Indexed: 04/16/2024]
Abstract
Studying the metabolic role of non-essential promiscuous enzymes is a challenging task, as genetic manipulations usually do not reveal at which point(s) of the metabolic network the enzymatic activity of such protein is beneficial for the organism. Each of the HAD-like phosphatases YcsE, YitU and YwtE of Bacillus subtilis catalyzes the dephosphorylation of 5-amino-6-ribitylamino-uracil 5'-phosphate, which is essential in the biosynthesis of riboflavin. Using CRISPR technology, we have found that the deletion of these genes, individually or in all possible combinations failed to cause riboflavin auxotrophy and did not result in significant growth changes. Analysis of flavin and adenylate content in B. subtilis knockout mutants showed that (i) there must be one or several still unidentified phosphatases that can replace the deleted proteins; (ii) such replacements, however, cannot fully restore the intracellular content of any of three flavins studied (riboflavin, FMN, FAD); (iii) whereas bacterial fitness was not significantly compromised by mutations, the intracellular balance of flavins and adenylates did show some significant changes.
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Affiliation(s)
- Alexandra Scharf
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Farshad La-Rostami
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Boris A Illarionov
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Vivien Nemes
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Anna M Feldmann
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Lars S Höft
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Henri Lösel
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
| | - Adelbert Bacher
- TUM School of Natural Sciences, Technical University of Munich, 85748, Garching, Germany
| | - Markus Fischer
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
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7
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Smith EL, Panis G, Woldemeskel SA, Viollier PH, Chien P, Goley ED. Regulation of the transcription factor CdnL promotes adaptation to nutrient stress in Caulobacter. PNAS NEXUS 2024; 3:pgae154. [PMID: 38650860 PMCID: PMC11034885 DOI: 10.1093/pnasnexus/pgae154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024]
Abstract
In response to nutrient deprivation, bacteria activate a conserved stress response pathway called the stringent response (SR). During SR activation in Caulobacter crescentus, SpoT synthesizes the secondary messengers guanosine 5'-diphosphate 3'-diphosphate and guanosine 5'-triphosphate 3'-diphosphate (collectively known as (p)ppGpp), which affect transcription by binding RNA polymerase (RNAP) to down-regulate anabolic genes. (p)ppGpp also impacts the expression of anabolic genes by controlling the levels and activities of their transcriptional regulators. In Caulobacter, a major regulator of anabolic genes is the transcription factor CdnL. If and how CdnL is controlled during the SR and why that might be functionally important are unclear. In this study, we show that CdnL is down-regulated posttranslationally during starvation in a manner dependent on SpoT and the ClpXP protease. Artificial stabilization of CdnL during starvation causes misregulation of ribosomal and metabolic genes. Functionally, we demonstrate that the combined action of SR transcriptional regulators and CdnL clearance allows for rapid adaptation to nutrient repletion. Moreover, cells that are unable to clear CdnL during starvation are outcompeted by wild-type cells when subjected to nutrient fluctuations. We hypothesize that clearance of CdnL during the SR, in conjunction with direct binding of (p)ppGpp and DksA to RNAP, is critical for altering the transcriptome in order to permit cell survival during nutrient stress.
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Affiliation(s)
- Erika L Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gaël Panis
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Selamawit Abi Woldemeskel
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Patrick H Viollier
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, MA 01003, USA
| | - Erin D Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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8
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Van Loon JC, Whitfield GB, Wong N, O'Neal L, Henrickson A, Demeler B, O'Toole GA, Parsek MR, Howell PL. Binding of GTP to BifA is required for the production of Pel-dependent biofilms in Pseudomonas aeruginosa. J Bacteriol 2024; 206:e0033123. [PMID: 38197635 PMCID: PMC10882990 DOI: 10.1128/jb.00331-23] [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: 10/06/2023] [Accepted: 12/13/2023] [Indexed: 01/11/2024] Open
Abstract
The Pel exopolysaccharide is one of the most mechanistically conserved and phylogenetically diverse bacterial biofilm matrix determinants. Pel is a major contributor to the structural integrity of Pseudomonas aeruginosa biofilms, and its biosynthesis is regulated by the binding of cyclic-3',5'-dimeric guanosine monophosphate (c-di-GMP) to the PelD receptor. c-di-GMP is synthesized from two molecules of guanosine triphosphate (GTP) by diguanylate cyclases with GGDEF domains and degraded by phosphodiesterases with EAL or HD-GYP domains. As the P. aeruginosa genome encodes 43 c-di-GMP metabolic enzymes, one way signaling specificity can be achieved is through direct interaction between specific enzyme-receptor pairs. Here, we show that the inner membrane hybrid GGDEF-EAL enzyme, BifA, directly interacts with PelD via its cytoplasmic HAMP, GGDEF, and EAL domains. Despite having no catalytic function, the degenerate active site motif of the BifA GGDEF domain (GGDQF) has retained the ability to bind GTP with micromolar affinity. Mutations that abolish GTP binding result in increased biofilm formation but stable global c-di-GMP levels. Our data suggest that BifA forms a dimer in solution and that GTP binding induces conformational changes in dimeric BifA that enhance the BifA-PelD interaction and stimulate its phosphodiesterase activity, thus reducing c-di-GMP levels and downregulating Pel biosynthesis. Structural comparisons between the dimeric AlphaFold2 model of BifA and the structures of other hybrid GGDEF-EAL proteins suggest that the regulation of BifA by GTP may occur through a novel mechanism.IMPORTANCEc-di-GMP is the most common cyclic dinucleotide used by bacteria to regulate phenotypes such as motility, biofilm formation, virulence factor production, cell cycle progression, and cell differentiation. While the identification and initial characterization of c-di-GMP metabolic enzymes are well established, our understanding of how these enzymes are regulated to provide signaling specificity remains understudied. Here we demonstrate that the inactive GGDEF domain of BifA binds GTP and regulates the adjacent phosphodiesterase EAL domain, ultimately downregulating Pel-dependent P. aeruginosa biofilm formation through an interaction with PelD. This discovery adds to the growing body of literature regarding how hybrid GGDEF-EAL enzymes are regulated and provides additional precedence for studying how direct interactions between c-di-GMP metabolic enzymes and effectors result in signaling specificity.
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Affiliation(s)
- Jaime C. Van Loon
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Gregory B. Whitfield
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Nicole Wong
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
| | - Lindsey O'Neal
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Amy Henrickson
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Borries Demeler
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada
| | - G. A. O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Matthew R. Parsek
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - P. Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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9
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Kago G, Turnbough CL, Salazar JC, Payne SM. (p)ppGpp is required for virulence of Shigella flexneri. Infect Immun 2024; 92:e0033423. [PMID: 38099658 PMCID: PMC10790822 DOI: 10.1128/iai.00334-23] [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: 08/22/2023] [Accepted: 11/16/2023] [Indexed: 01/17/2024] Open
Abstract
Infection by the enteric pathogen Shigella flexneri requires transit through the gastrointestinal tract and invasion of and replication within the cells of the host colonic epithelium. This process exposes the pathogen to a range of diverse microenvironments. Furthermore, the unique composition and physical environment of the eukaryotic cell cytosol represents a stressful environment for S. flexneri, and extensive physiological adaptations are needed for the bacterium to thrive. In this work, we show that disrupting synthesis of the stringent response alarmone (p)ppGpp in S. flexneri diminished expression of key virulence genes, including ipaA, ipaB, ipaC, and icsA, and it reduced bacterial invasion and intercellular spread. Deletion of the (p)ppGpp synthase gene relA alone had no effect on S. flexneri virulence, but disruption of both relA and the (p)ppGpp synthase/hydrolase gene spoT resulted in loss of (p)ppGpp synthesis and virulence. While the relA spoT deletion mutant was able to invade a cultured human epithelial cell monolayer, albeit at reduced levels, it was unable to maintain the infection and spread to adjacent cells, as indicated by loss of plaque formation. Complementation with spoT on a plasmid vector restored plaque formation. Thus, SpoT alone is sufficient to provide the necessary level of (p)ppGpp for virulence. These results indicate that (p)ppGpp is required for S. flexneri virulence and adaptation to the intracellular environment, adding to the repertoire of signaling pathways that affect Shigella pathogenesis.
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Affiliation(s)
- Grace Kago
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - Charles L. Turnbough
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Juan Carlos Salazar
- Programa de Microbiología y Micología, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Shelley M. Payne
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
- John Ring LaMontagne Center for Infectious Disease, The University of Texas at Austin, Austin, Texas, USA
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10
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Smith EL, Panis G, Woldemeskel SA, Viollier PH, Chien P, Goley ED. Regulation of the transcription factor CdnL promotes adaptation to nutrient stress in Caulobacter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572625. [PMID: 38187569 PMCID: PMC10769358 DOI: 10.1101/2023.12.20.572625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
In response to nutrient deprivation, bacteria activate a conserved stress response pathway called the stringent response (SR). During SR activation in Caulobacter crescentus, SpoT synthesizes the secondary messengers (p)ppGpp, which affect transcription by binding RNA polymerase to downregulate anabolic genes. (p)ppGpp also impacts expression of anabolic genes by controlling the levels and activities of their transcriptional regulators. In Caulobacter, a major regulator of anabolic genes is the transcription factor CdnL. If and how CdnL is controlled during the SR and why that might be functionally important is unclear. Here, we show that CdnL is downregulated post-translationally during starvation in a manner dependent on SpoT and the ClpXP protease. Inappropriate stabilization of CdnL during starvation causes misregulation of ribosomal and metabolic genes. Functionally, we demonstrate that the combined action of SR transcriptional regulators and CdnL clearance allows for rapid adaptation to nutrient repletion. Moreover, cells that are unable to clear CdnL during starvation are outcompeted by wild-type cells when subjected to nutrient fluctuations. We hypothesize that clearance of CdnL during the SR, in conjunction with direct binding of (p)ppGpp and DksA to RNAP, is critical for altering the transcriptome in order to permit cell survival during nutrient stress.
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Affiliation(s)
- Erika L. Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
| | - Gaäl Panis
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland, 1211
| | - Selamawit Abi Woldemeskel
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
- BlueRock Therapeutics, Cambridge, Massachusetts, 02142 (current)
| | - Patrick H. Viollier
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland, 1211
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, Massachusetts, 01003
| | - Erin D. Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
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11
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Ontai-Brenning A, Hamchand R, Crawford JM, Goodman AL. Gut microbes modulate (p)ppGpp during a time-restricted feeding regimen. mBio 2023; 14:e0190723. [PMID: 37971266 PMCID: PMC10746209 DOI: 10.1128/mbio.01907-23] [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: 07/25/2023] [Accepted: 10/09/2023] [Indexed: 11/19/2023] Open
Abstract
IMPORTANCE Mammals do not eat continuously, instead concentrating their feeding to a restricted portion of the day. This behavior presents the mammalian gut microbiota with a fluctuating environment with consequences for host-microbiome interaction, infection risk, immune response, drug metabolism, and other aspects of health. We demonstrate that in mice, gut microbes elevate levels of an intracellular signaling molecule, (p)ppGpp, during the fasting phase of a time-restricted feeding regimen. Disabling this response in a representative human gut commensal species significantly reduces colonization during this host-fasting phase. This response appears to be general across species and conserved across mammalian gut communities, highlighting a pathway that allows healthy gut microbiomes to maintain stability in an unstable environment.
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Affiliation(s)
- Amy Ontai-Brenning
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Randy Hamchand
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Institute of Biomolecular Design & Discovery, Yale University, West Haven, Connecticut, USA
| | - Jason M. Crawford
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Institute of Biomolecular Design & Discovery, Yale University, West Haven, Connecticut, USA
| | - Andrew L. Goodman
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
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12
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Gruffaz C, Smirnov A. GTPase Era at the heart of ribosome assembly. Front Mol Biosci 2023; 10:1263433. [PMID: 37860580 PMCID: PMC10582724 DOI: 10.3389/fmolb.2023.1263433] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/21/2023] [Indexed: 10/21/2023] Open
Abstract
Ribosome biogenesis is a key process in all organisms. It relies on coordinated work of multiple proteins and RNAs, including an array of assembly factors. Among them, the GTPase Era stands out as an especially deeply conserved protein, critically required for the assembly of bacterial-type ribosomes from Escherichia coli to humans. In this review, we bring together and critically analyze a wealth of phylogenetic, biochemical, structural, genetic and physiological data about this extensively studied but still insufficiently understood factor. We do so using a comparative and, wherever possible, synthetic approach, by confronting observations from diverse groups of bacteria and eukaryotic organelles (mitochondria and chloroplasts). The emerging consensus posits that Era intervenes relatively early in the small subunit biogenesis and is essential for the proper shaping of the platform which, in its turn, is a prerequisite for efficient translation. The timing of Era action on the ribosome is defined by its interactions with guanosine nucleotides [GTP, GDP, (p)ppGpp], ribosomal RNA, and likely other factors that trigger or delay its GTPase activity. As a critical nexus of the small subunit biogenesis, Era is subject to sophisticated regulatory mechanisms at the transcriptional, post-transcriptional, and post-translational levels. Failure of these mechanisms or a deficiency in Era function entail dramatic generalized consequences for the protein synthesis and far-reaching, pleiotropic effects on the organism physiology, such as the Perrault syndrome in humans.
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Affiliation(s)
- Christelle Gruffaz
- UMR7156- Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, Centre National de la Recherche Scientifique (CNRS), Strasbourg, France
| | - Alexandre Smirnov
- UMR7156- Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, Centre National de la Recherche Scientifique (CNRS), Strasbourg, France
- University of Strasbourg Institute for Advanced Study (USIAS), Strasbourg, France
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13
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Wu LY, Piedade GJ, Moore RM, Harrison AO, Martins AM, Bidle KD, Polson SW, Sakowski EG, Nissimov JI, Dums JT, Ferrell BD, Wommack KE. Ubiquitous, B 12-dependent virioplankton utilizing ribonucleotide-triphosphate reductase demonstrate interseasonal dynamics and associate with a diverse range of bacterial hosts in the pelagic ocean. ISME COMMUNICATIONS 2023; 3:108. [PMID: 37789093 PMCID: PMC10547690 DOI: 10.1038/s43705-023-00306-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 10/05/2023]
Abstract
Through infection and lysis of their coexisting bacterial hosts, viruses impact the biogeochemical cycles sustaining globally significant pelagic oceanic ecosystems. Currently, little is known of the ecological interactions between lytic viruses and their bacterial hosts underlying these biogeochemical impacts at ecosystem scales. This study focused on populations of lytic viruses carrying the B12-dependent Class II monomeric ribonucleotide reductase (RNR) gene, ribonucleotide-triphosphate reductase (Class II RTPR), documenting seasonal changes in pelagic virioplankton and bacterioplankton using amplicon sequences of Class II RTPR and the 16S rRNA gene, respectively. Amplicon sequence libraries were analyzed using compositional data analysis tools that account for the compositional nature of these data. Both virio- and bacterioplankton communities responded to environmental changes typically seen across seasonal cycles as well as shorter term upwelling-downwelling events. Defining Class II RTPR-carrying viral populations according to major phylogenetic clades proved a more robust means of exploring virioplankton ecology than operational taxonomic units defined by percent sequence homology. Virioplankton Class II RTPR populations showed positive associations with a broad phylogenetic diversity of bacterioplankton including dominant taxa within pelagic oceanic ecosystems such as Prochlorococcus and SAR11. Temporal changes in Class II RTPR virioplankton, occurring as both free viruses and within infected cells, indicated possible viral-host pairs undergoing sustained infection and lysis cycles throughout the seasonal study. Phylogenetic relationships inferred from Class II RTPR sequences mirrored ecological patterns in virio- and bacterioplankton populations demonstrating possible genome to phenome associations for an essential viral replication gene.
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Affiliation(s)
- Ling-Yi Wu
- Theoretical Biology and Bioinformatics, Science4Life, Utrecht University, Padualaan 8, Utrecht, 3584 CH, the Netherlands
| | - Gonçalo J Piedade
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, 1797 SZ, t'Horntje, The Netherlands
- Department of Oceanography and Fisheries and Ocean Sciences Institute-OKEANOS, University of the Azores, 9901-862 Horta, Faial, Azores, Portugal
| | - Ryan M Moore
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
| | - Amelia O Harrison
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
| | - Ana M Martins
- Department of Oceanography and Fisheries and Ocean Sciences Institute-OKEANOS, University of the Azores, 9901-862 Horta, Faial, Azores, Portugal
| | - Kay D Bidle
- Department of Marine and Coastal Sciences, Rutgers University, 71 Dudley Rd., New Brunswick, NJ, 08901, USA
| | - Shawn W Polson
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
| | - Eric G Sakowski
- Department of Earth Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Jozef I Nissimov
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, ON, N2L 3G1, Canada
| | - Jacob T Dums
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
- Biotechnology Program, North Carolina State University, 2800 Faucette Dr, Raleigh, NC, 27695, USA
| | - Barbra D Ferrell
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
| | - K Eric Wommack
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA.
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14
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Njenga R, Boele J, Öztürk Y, Koch HG. Coping with stress: How bacteria fine-tune protein synthesis and protein transport. J Biol Chem 2023; 299:105163. [PMID: 37586589 PMCID: PMC10502375 DOI: 10.1016/j.jbc.2023.105163] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/08/2023] [Accepted: 08/10/2023] [Indexed: 08/18/2023] Open
Abstract
Maintaining a functional proteome under different environmental conditions is challenging for every organism, in particular for unicellular organisms, such as bacteria. In order to cope with changing environments and stress conditions, bacteria depend on strictly coordinated proteostasis networks that control protein production, folding, trafficking, and degradation. Regulation of ribosome biogenesis and protein synthesis are cornerstones of this cellular adaptation in all domains of life, which is rationalized by the high energy demand of both processes and the increased resistance of translationally silent cells against internal or external poisons. Reduced protein synthesis ultimately also reduces the substrate load for protein transport systems, which are required for maintaining the periplasmic, inner, and outer membrane subproteomes. Consequences of impaired protein transport have been analyzed in several studies and generally induce a multifaceted response that includes the upregulation of chaperones and proteases and the simultaneous downregulation of protein synthesis. In contrast, generally less is known on how bacteria adjust the protein targeting and transport machineries to reduced protein synthesis, e.g., when cells encounter stress conditions or face nutrient deprivation. In the current review, which is mainly focused on studies using Escherichia coli as a model organism, we summarize basic concepts on how ribosome biogenesis and activity are regulated under stress conditions. In addition, we highlight some recent developments on how stress conditions directly impair protein targeting to the bacterial membrane. Finally, we describe mechanisms that allow bacteria to maintain the transport of stress-responsive proteins under conditions when the canonical protein targeting pathways are impaired.
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Affiliation(s)
- Robert Njenga
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany; Faculty of Biology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Julian Boele
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Yavuz Öztürk
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany.
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15
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Wang B, Said N, Hilal T, Finazzo M, Wahl MC, Artsimovitch I. Transcription termination factor ρ polymerizes under stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.18.553922. [PMID: 37645988 PMCID: PMC10462130 DOI: 10.1101/2023.08.18.553922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Bacterial RNA helicase ρ is a genome sentinel that terminates synthesis of damaged and junk RNAs that are not translated by the ribosome. Co-transcriptional RNA surveillance by ρ is essential for quality control of the transcriptome during optimal growth. However, it is unclear how bacteria protect their RNAs from overzealous ρ during dormancy or stress, conditions common in natural habitats. Here we used cryogenic electron microscopy, biochemical, and genetic approaches to show that residue substitutions, ADP, or ppGpp promote hyper-oligomerization of Escherichia coli ρ. Our results demonstrate that nucleotides bound at subunit interfaces control ρ switching from active hexamers to inactive higher-order oligomers and extended filaments. Polymers formed upon exposure to antibiotics or ppGpp disassemble when stress is relieved, thereby directly linking termination activity to cellular physiology. Inactivation of ρ through hyper-oligomerization is a regulatory strategy shared by RNA polymerases, ribosomes, and metabolic enzymes across all life.
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Affiliation(s)
- Bing Wang
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Nelly Said
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
| | - Tarek Hilal
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Research Center of Electron Microscopy and Core Facility BioSupraMol, Fabeckstr. 36a, 14195 Berlin, Germany
| | - Mark Finazzo
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Markus C. Wahl
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of Structural Biochemistry, Takustr. 6, D-14195 Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
| | - Irina Artsimovitch
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH, USA
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16
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Wang M, Tang NY, Xie S, Watt RM. Functional Characterization of Small Alarmone Synthetase and Small Alarmone Hydrolase Proteins from Treponema denticola. Microbiol Spectr 2023; 11:e0510022. [PMID: 37289081 PMCID: PMC10434055 DOI: 10.1128/spectrum.05100-22] [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: 12/11/2022] [Accepted: 05/18/2023] [Indexed: 06/09/2023] Open
Abstract
The stringent response enables bacteria to survive nutrient starvation, antibiotic challenge, and other threats to cellular survival. Two alarmone (magic spot) second messengers, guanosine pentaphosphate (pppGpp) and guanosine tetraphosphate (ppGpp), which are synthesized by RelA/SpoT homologue (RSH) proteins, play central roles in the stringent response. The pathogenic oral spirochete bacterium Treponema denticola lacks a long-RSH homologue but encodes putative small alarmone synthetase (Tde-SAS, TDE1711) and small alarmone hydrolase (Tde-SAH, TDE1690) proteins. Here, we characterize the respective in vitro and in vivo activities of Tde-SAS and Tde-SAH, which respectively belong to the previously uncharacterized RSH families DsRel and ActSpo2. The tetrameric 410-amino acid (aa) Tde-SAS protein preferentially synthesizes ppGpp over pppGpp and a third alarmone, pGpp. Unlike RelQ homologues, alarmones do not allosterically stimulate the synthetic activities of Tde-SAS. The ~180 aa C-terminal tetratricopeptide repeat (TPR) domain of Tde-SAS acts as a brake on the alarmone synthesis activities of the ~220-aa N-terminal catalytic domain. Tde-SAS also synthesizes "alarmone-like" nucleotides such as adenosine tetraphosphate (ppApp), albeit at considerably lower rates. The 210-aa Tde-SAH protein efficiently hydrolyzes all guanosine and adenosine-based alarmones in a Mn(II) ion-dependent manner. Using a growth assays with a ΔrelAΔspoT strain of Escherichia coli that is deficient in pppGpp/ppGpp synthesis, we demonstrate that Tde-SAS can synthesize alarmones in vivo to restore growth in minimal media. Taken together, our results add to our holistic understanding of alarmone metabolism across diverse bacterial species. IMPORTANCE The spirochete bacterium Treponema denticola is a common component of the oral microbiota. However, it may play important pathological roles in multispecies oral infectious diseases such as periodontitis: a severe and destructive form of gum disease, which is a major cause of tooth loss in adults. The operation of the stringent response, a highly conserved survival mechanism, is known to help many bacterial species cause persistent or virulent infections. By characterizing the biochemical functions of the proteins putatively responsible for the stringent response in T. denticola, we may gain molecular insight into how this bacterium can survive within harsh oral environments and promote infection. Our results also expand our general understanding of proteins that synthesize nucleotide-based intracellular signaling molecules in bacteria.
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Affiliation(s)
- Miao Wang
- Faculty of Dentistry, The University of Hong Kong, Pok Fu Lam, Hong Kong SAR, China
| | - Nga-Yeung Tang
- Department of Pathology and Laboratory Medicine, Beaumont Health, Royal Oak, Michigan, USA
- Department of Pathology and Laboratory Medicine, Oakland University William Beaumont School of Medicine, Auburn Hills, Michigan, USA
| | - Shujie Xie
- Faculty of Dentistry, The University of Hong Kong, Pok Fu Lam, Hong Kong SAR, China
| | - Rory M. Watt
- Faculty of Dentistry, The University of Hong Kong, Pok Fu Lam, Hong Kong SAR, China
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17
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Brückner S, Müller F, Schadowski L, Kalle T, Weber S, Marino EC, Kutscher B, Möller AM, Adler S, Begerow D, Steinchen W, Bange G, Narberhaus F. (p)ppGpp and moonlighting RNases influence the first step of lipopolysaccharide biosynthesis in Escherichia coli. MICROLIFE 2023; 4:uqad031. [PMID: 37426605 PMCID: PMC10326835 DOI: 10.1093/femsml/uqad031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 05/12/2023] [Accepted: 06/13/2023] [Indexed: 07/11/2023]
Abstract
The outer membrane (OM) protects Gram-negative bacteria from harsh environmental conditions and provides intrinsic resistance to many antimicrobial compounds. The asymmetric OM is characterized by phospholipids in the inner leaflet and lipopolysaccharides (LPS) in the outer leaflet. Previous reports suggested an involvement of the signaling nucleotide ppGpp in cell envelope homeostasis in Escherichia coli. Here, we investigated the effect of ppGpp on OM biosynthesis. We found that ppGpp inhibits the activity of LpxA, the first enzyme of LPS biosynthesis, in a fluorometric in vitro assay. Moreover, overproduction of LpxA resulted in elongated cells and shedding of outer membrane vesicles (OMVs) with altered LPS content. These effects were markedly stronger in a ppGpp-deficient background. We further show that RnhB, an RNase H isoenzyme, binds ppGpp, interacts with LpxA, and modulates its activity. Overall, our study uncovered new regulatory players in the early steps of LPS biosynthesis, an essential process with many implications in the physiology and susceptibility to antibiotics of Gram-negative commensals and pathogens.
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Affiliation(s)
- Simon Brückner
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Fabian Müller
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Laura Schadowski
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Tyll Kalle
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Sophia Weber
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Emily C Marino
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Blanka Kutscher
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Anna-Maria Möller
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Sabine Adler
- Evolution of Plants and Fungi, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
| | - Dominik Begerow
- Evolution of Plants and Fungi, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, Bochum, Germany
- Organismische Botanik und Mykologie, Institut für Planzenwissenschaften und Mikrobiologie, Fachbereich Biologie, Universität Hamburg,Ohnhorststrasse 18, Hamburg, Germany
| | - Wieland Steinchen
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Philipps-University Marburg, Karl-von-Frisch-Strasse 14, Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Philipps-University Marburg, Karl-von-Frisch-Strasse 14, Marburg, Germany
| | - Franz Narberhaus
- Corresponding author. Faculty of Biology and Biotechnology, Microbial Biology, Ruhr University Bochum, Universitätsstrasse 150, NDEF 06/784, 44780 Bochum, Germany. Tel: +492343223100; Fax: +492343214620; E-mail:
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18
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Lamprecht O, Ratnikava M, Jacek P, Kaganovitch E, Buettner N, Fritz K, Biazruchka I, Köhler R, Pietsch J, Sourjik V. Regulation by cyclic di-GMP attenuates dynamics and enhances robustness of bimodal curli gene activation in Escherichia coli. PLoS Genet 2023; 19:e1010750. [PMID: 37186613 DOI: 10.1371/journal.pgen.1010750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 05/25/2023] [Accepted: 04/18/2023] [Indexed: 05/17/2023] Open
Abstract
Curli amyloid fibers are a major constituent of the extracellular biofilm matrix formed by bacteria of the Enterobacteriaceae family. Within Escherichia coli biofilms, curli gene expression is limited to a subpopulation of bacteria, leading to heterogeneity of extracellular matrix synthesis. Here we show that bimodal activation of curli gene expression also occurs in well-mixed planktonic cultures of E. coli, resulting in all-or-none stochastic differentiation into distinct subpopulations of curli-positive and curli-negative cells at the entry into the stationary phase of growth. Stochastic curli activation in individual E. coli cells could further be observed during continuous growth in a conditioned medium in a microfluidic device, which further revealed that the curli-positive state is only metastable. In agreement with previous reports, regulation of curli gene expression by the second messenger c-di-GMP via two pairs of diguanylate cyclase and phosphodiesterase enzymes, DgcE/PdeH and DgcM/PdeR, modulates the fraction of curli-positive cells. Unexpectedly, removal of this regulatory network does not abolish the bimodality of curli gene expression, although it affects dynamics of activation and increases heterogeneity of expression levels among individual cells. Moreover, the fraction of curli-positive cells within an E. coli population shows stronger dependence on growth conditions in the absence of regulation by DgcE/PdeH and DgcM/PdeR pairs. We thus conclude that, while not required for the emergence of bimodal curli gene expression in E. coli, this c-di-GMP regulatory network attenuates the frequency and dynamics of gene activation and increases its robustness to cellular heterogeneity and environmental variation.
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Affiliation(s)
- Olga Lamprecht
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Maryia Ratnikava
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Paulina Jacek
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Eugen Kaganovitch
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Nina Buettner
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Kirstin Fritz
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Ina Biazruchka
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Robin Köhler
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Julian Pietsch
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Victor Sourjik
- Max Planck Institute for Terrestrial Microbiology and Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
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19
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Ho P, Chen Y, Biswas S, Canfield E, Abdolvahabi A, Feldman DE. Bacteriophage antidefense genes that neutralize TIR and STING immune responses. Cell Rep 2023; 42:112305. [PMID: 36952342 DOI: 10.1016/j.celrep.2023.112305] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 12/09/2022] [Accepted: 03/08/2023] [Indexed: 03/24/2023] Open
Abstract
Programmed cell suicide of infected bacteria, known as abortive infection (Abi), serves as an immune defense strategy to prevent the propagation of bacteriophage viruses. Many Abi systems utilize bespoke cyclic nucleotide immune messengers generated upon infection to mobilize cognate death effectors. Here, we identify a family of bacteriophage nucleotidyltransferases (NTases) that synthesize competitor cyclic dinucleotide (CDN) ligands and inhibit TIR NADase effectors activated via a linked STING CDN sensor domain (TIR-STING). Through a functional screen of NTase-adjacent phage genes, we uncover candidate inhibitors of cell suicide induced by heterologous expression of tonically active TIR-STING. Among these, we demonstrate that a virus MazG-like nucleotide pyrophosphohydrolase, Atd1, depletes the starvation alarmone (p)ppGpp, revealing a potential role for the alarmone-activated host toxin MazF as an executioner of TIR-driven Abi. Phage NTases and counterdefenses like Atd1 preserve host viability to ensure virus propagation and represent tools to modulate TIR and STING immune responses.
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Affiliation(s)
- Peiyin Ho
- Department of Pathology, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Yibu Chen
- Bioinformatics Service, Department of Health Sciences Libraries, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Subarna Biswas
- Department of Surgery, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Ethan Canfield
- University of Southern California, School of Pharmacy, Los Angeles, CA 90033, USA
| | - Alireza Abdolvahabi
- University of Southern California, School of Pharmacy, Los Angeles, CA 90033, USA
| | - Douglas E Feldman
- Department of Pathology, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA.
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20
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Pawlak JB, Hsu JCC, Xia H, Han P, Suh HW, Grove TL, Morrison J, Shi PY, Cresswell P, Laurent-Rolle M. CMPK2 restricts Zika virus replication by inhibiting viral translation. PLoS Pathog 2023; 19:e1011286. [PMID: 37075076 PMCID: PMC10150978 DOI: 10.1371/journal.ppat.1011286] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 05/01/2023] [Accepted: 03/09/2023] [Indexed: 04/20/2023] Open
Abstract
Flaviviruses continue to emerge as global health threats. There are currently no Food and Drug Administration (FDA) approved antiviral treatments for flaviviral infections. Therefore, there is a pressing need to identify host and viral factors that can be targeted for effective therapeutic intervention. Type I interferon (IFN-I) production in response to microbial products is one of the host's first line of defense against invading pathogens. Cytidine/uridine monophosphate kinase 2 (CMPK2) is a type I interferon-stimulated gene (ISG) that exerts antiviral effects. However, the molecular mechanism by which CMPK2 inhibits viral replication is unclear. Here, we report that CMPK2 expression restricts Zika virus (ZIKV) replication by specifically inhibiting viral translation and that IFN-I- induced CMPK2 contributes significantly to the overall antiviral response against ZIKV. We demonstrate that expression of CMPK2 results in a significant decrease in the replication of other pathogenic flaviviruses including dengue virus (DENV-2), Kunjin virus (KUNV) and yellow fever virus (YFV). Importantly, we determine that the N-terminal domain (NTD) of CMPK2, which lacks kinase activity, is sufficient to restrict viral translation. Thus, its kinase function is not required for CMPK2's antiviral activity. Furthermore, we identify seven conserved cysteine residues within the NTD as critical for CMPK2 antiviral activity. Thus, these residues may form an unknown functional site in the NTD of CMPK2 contributing to its antiviral function. Finally, we show that mitochondrial localization of CMPK2 is required for its antiviral effects. Given its broad antiviral activity against flaviviruses, CMPK2 is a promising potential pan-flavivirus inhibitor.
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Affiliation(s)
- Joanna B. Pawlak
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Jack Chun-Chieh Hsu
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Hongjie Xia
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Patrick Han
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Hee-Won Suh
- Department of Biomedical Engineering, Yale University School of Engineering and Applied Science, New Haven, Connecticut, United States of America
| | - Tyler L. Grove
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Juliet Morrison
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, United States of America
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Institute for Drug Discovery, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Peter Cresswell
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Maudry Laurent-Rolle
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, United States of America
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21
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Leiva LE, Zegarra V, Bange G, Ibba M. At the Crossroad of Nucleotide Dynamics and Protein Synthesis in Bacteria. Microbiol Mol Biol Rev 2023; 87:e0004422. [PMID: 36853029 PMCID: PMC10029340 DOI: 10.1128/mmbr.00044-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Nucleotides are at the heart of the most essential biological processes in the cell, be it as key protagonists in the dogma of molecular biology or by regulating multiple metabolic pathways. The dynamic nature of nucleotides, the cross talk between them, and their constant feedback to and from the cell's metabolic state position them as a hallmark of adaption toward environmental and growth challenges. It has become increasingly clear how the activity of RNA polymerase, the synthesis and maintenance of tRNAs, mRNA translation at all stages, and the biogenesis and assembly of ribosomes are fine-tuned by the pools of intracellular nucleotides. With all aspects composing protein synthesis involved, the ribosome emerges as the molecular hub in which many of these nucleotides encounter each other and regulate the state of the cell. In this review, we aim to highlight intracellular nucleotides in bacteria as dynamic characters permanently cross talking with each other and ultimately regulating protein synthesis at various stages in which the ribosome is mainly the principal character.
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Affiliation(s)
- Lorenzo Eugenio Leiva
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Victor Zegarra
- Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
- Department of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology, Philipps-University Marburg, Marburg, Germany
- Department of Chemistry, Philipps-University Marburg, Marburg, Germany
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Michael Ibba
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
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22
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Abstract
As rapidly growing bacteria begin to exhaust essential nutrients, they enter a state of reduced growth, ultimately leading to stasis or quiescence. Investigation of the response to nutrient limitation has focused largely on the consequences of amino acid starvation, known as the "stringent response." Here, an uncharged tRNA in the A-site of the ribosome stimulates the ribosome-associated protein RelA to synthesize the hyperphosphorylated guanosine nucleotides (p)ppGpp that mediate a global slowdown of growth and biosynthesis. Investigations of the stringent response typically employ experimental methodologies that rapidly stimulate (p)ppGpp synthesis by abruptly increasing the fraction of uncharged tRNAs, either by explicit amino starvation or by inhibition of tRNA charging. Consequently, these methodologies inhibit protein translation, thereby interfering with the cellular pathways that respond to nutrient limitation. Thus, complete and/or rapid starvation is a problematic experimental paradigm for investigating bacterial responses to physiologically relevant nutrient-limited states.
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Affiliation(s)
- Jonathan Dworkin
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
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23
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Metabolic Promiscuity of an Orphan Small Alarmone Hydrolase Facilitates Bacterial Environmental Adaptation. mBio 2022; 13:e0242222. [PMID: 36472432 PMCID: PMC9765508 DOI: 10.1128/mbio.02422-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Small alarmone hydrolases (SAHs) are alarmone metabolizing enzymes found in both metazoans and bacteria. In metazoans, the SAH homolog Mesh1 is reported to function in cofactor metabolism by hydrolyzing NADPH to NADH. In bacteria, SAHs are often identified in genomes with toxic alarmone synthetases for self-resistance. Here, we characterized a bacterial orphan SAH, i.e., without a toxic alarmone synthetase, in the phytopathogen Xanthomonas campestris pv. campestris (XccSAH) and found that it metabolizes both cellular alarmones and cofactors. In vitro, XccSAH displays abilities to hydrolyze multiple nucleotides, including pppGpp, ppGpp, pGpp, pppApp, and NADPH. In vivo, X. campestris pv. campestris cells lacking sah accumulated higher levels of cellular (pp)pGpp and NADPH compared to wild-type cells upon amino acid starvation. In addition, X. campestris pv. campestris mutants lacking sah were more sensitive to killing by Pseudomonas during interbacterial competition. Interestingly, loss of sah also resulted in reduced growth in amino acid-replete medium, a condition that did not induce (pp)pGpp or pppApp accumulation. Further metabolomic characterization revealed strong depletion of NADH levels in the X. campestris pv. campestris mutant lacking sah, suggesting that NADPH/NADH regulation is an evolutionarily conserved function of both bacterial and metazoan SAHs and Mesh1. Overall, our work demonstrates a regulatory role of bacterial SAHs as tuners of stress responses and metabolism, beyond functioning as antitoxins. IMPORTANCE Small alarmone hydrolases (SAHs) comprise a widespread family of alarmone metabolizing enzymes. In metazoans, SAHs have been reported to control multiple aspects of physiology and stress resistance through alarmone and NADPH metabolisms, but their physiological functions in bacteria is mostly uncharacterized except for a few reports as antitoxins. Here, we identified an SAH functioning independently of toxins in the phytopathogen Xanthomonas campestris pv. campestris. We found that XccSAH hydrolyzed multiple alarmones and NADPH in vitro, and X. campestris pv. campestris mutants lacking sah displayed increased alarmone levels during starvation, loss of interspecies competitive fitness, growth defects, and strong reduction in NADH. Our findings reveal the importance of NADPH hydrolysis by a bacterial SAH. Our work is also the first report of significant physiological roles of bacterial SAHs beyond functioning as antitoxins and suggests that SAHs have far broader physiological roles and share similar functions across domains of life.
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24
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Bonar CD, Han J, Wang R, Panchapakesan SSS, Unrau PJ. E. coli 6S RNA complexed to RNA polymerase maintains product RNA synthesis at low cellular ATP levels by initiation with noncanonical initiator nucleotides. RNA (NEW YORK, N.Y.) 2022; 28:1643-1658. [PMID: 36198425 PMCID: PMC9670815 DOI: 10.1261/rna.079356.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
The E. coli 6S RNA is an RNA polymerase (RNAP) inhibitor that competes with σ70-dependent DNA promoters for binding to RNAP holoenzyme (RNAP:σ70). The 6S RNA when bound is then used as a template to synthesize a short product RNA (pRNA; usually 13-nt-long). This pRNA changes the 6S RNA structure, triggering the 6S RNA:pRNA complex to release and allowing DNA-dependent housekeeping gene expression to resume. In high nutrient conditions, 6S RNA turnover is extremely rapid but becomes very slow in low nutrient environments. This leads to a large accumulation of inhibited RNAP:σ70 in stationary phase. As pRNA initiates synthesis with ATP, we and others have proposed that the 6S RNA release rate strongly depends on ATP levels as a proxy for sensing the cellular metabolic state. By purifying endogenous 6S RNA:pRNA complexes using RNA Mango and using reverse transcriptase to generate pRNA-cDNA chimeras, we demonstrate that 6S RNA:pRNA formation can be simultaneous with 6S RNA 5' maturation. More importantly, we find a dramatic accumulation of capped pRNAs during stationary phase. This indicates that ATP levels in stationary phase are low enough for noncanonical initiator nucleotides (NCINs) such as NAD+ and NADH to initiate pRNA synthesis. In vitro, mutation of the conserved 6S RNA template sequence immediately upstream of the pRNA transcriptional start site can increase or decrease the pRNA capping efficiency, suggesting that evolution has tuned the biological 6S RNA sequence for an optimal capping rate. NCIN-initiated pRNA synthesis may therefore be essential for cell viability in low nutrient conditions.
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Affiliation(s)
- Christopher D Bonar
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Jonathan Han
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada
- Faculty of Medicine, University of British Columbia, Vancouver, B.C. V6T 1Z3, Canada
| | - Robert Wang
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada
- Cheriton School of Computer Science, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Shanker Shyam Sundhar Panchapakesan
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Peter J Unrau
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada
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25
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Fernández-Vázquez J, Cabrer-Panes JD, Åberg A, Juárez A, Madrid C, Gaviria-Cantin T, Fernández-Coll L, Vargas-Sinisterra AF, Jiménez CJ, Balsalobre C. ppGpp, the General Stress Response Alarmone, Is Required for the Expression of the α-Hemolysin Toxin in the Uropathogenic Escherichia coli Isolate, J96. Int J Mol Sci 2022; 23:ijms232012256. [PMID: 36293122 PMCID: PMC9602796 DOI: 10.3390/ijms232012256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 11/08/2022] Open
Abstract
ppGpp is an intracellular sensor that, in response to different types of stress, coordinates the rearrangement of the gene expression pattern of bacteria to promote adaptation and survival to new environmental conditions. First described to modulate metabolic adaptive responses, ppGpp modulates the expression of genes belonging to very diverse functional categories. In Escherichia coli, ppGpp regulates the expression of cellular factors that are important during urinary tract infections. Here, we characterize the role of this alarmone in the regulation of the hlyCABDII operon of the UPEC isolate J96, encoding the toxin α-hemolysin that induces cytotoxicity during infection of bladder epithelial cells. ppGpp is required for the expression of the α-hemolysin encoded in hlyCABDII by stimulating its transcriptional expression. Prototrophy suppressor mutations in a ppGpp-deficient strain restore the α-hemolysin expression from this operon to wild-type levels, confirming the requirement of ppGpp for its expression. ppGpp stimulates hlyCABDII expression independently of RpoS, RfaH, Zur, and H-NS. The expression of hlyCABDII is promoted at 37 °C and at low osmolarity. ppGpp is required for the thermoregulation but not for the osmoregulation of the hlyCABDII operon. Studies in both commensal and UPEC isolates demonstrate that no UPEC specific factor is strictly required for the ppGpp-mediated regulation described. Our data further support the role of ppGpp participating in the coordinated regulation of the expression of bacterial factors required during infection.
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Affiliation(s)
- Jorge Fernández-Vázquez
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Juan David Cabrer-Panes
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Anna Åberg
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-90187 Umeå, Sweden
| | - Antonio Juárez
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
| | - Cristina Madrid
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Tania Gaviria-Cantin
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Llorenç Fernández-Coll
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | | | - Carlos Jonay Jiménez
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Carlos Balsalobre
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, 08028 Barcelona, Spain
- Correspondence: ; Tel.: +34-934-034-622
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26
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Abstract
Since Jacques Monod's foundational work in the 1940s, investigators studying bacterial physiology have largely (but not exclusively) focused on the exponential phase of bacterial cultures, which is characterized by rapid growth and high biosynthesis activity in the presence of excess nutrients. However, this is not the predominant state of bacterial life. In nature, most bacteria experience nutrient limitation most of the time. In fact, investigators even prior to Monod had identified other aspects of bacterial growth, including what is now known as the stationary phase, when nutrients become limiting. This review will discuss how bacteria transition to growth arrest in response to nutrient limitation through changes in transcription, translation, and metabolism. We will then examine how these changes facilitate survival during potentially extended periods of nutrient limitation, with particular attention to the metabolic strategies that underpin bacterial longevity in this state.
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Affiliation(s)
- Jonathan Dworkin
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA;
| | - Caroline S Harwood
- Department of Microbiology, University of Washington, Seattle, Washington, USA;
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27
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Takada H, Mandell ZF, Yakhnin H, Glazyrina A, Chiba S, Kurata T, Wu KJY, Tresco BIC, Myers AG, Aktinson GC, Babitzke P, Hauryliuk V. Expression of Bacillus subtilis ABCF antibiotic resistance factor VmlR is regulated by RNA polymerase pausing, transcription attenuation, translation attenuation and (p)ppGpp. Nucleic Acids Res 2022; 50:6174-6189. [PMID: 35699226 PMCID: PMC9226507 DOI: 10.1093/nar/gkac497] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/22/2022] [Accepted: 05/26/2022] [Indexed: 12/14/2022] Open
Abstract
Since antibiotic resistance is often associated with a fitness cost, bacteria employ multi-layered regulatory mechanisms to ensure that expression of resistance factors is restricted to times of antibiotic challenge. In Bacillus subtilis, the chromosomally-encoded ABCF ATPase VmlR confers resistance to pleuromutilin, lincosamide and type A streptogramin translation inhibitors. Here we show that vmlR expression is regulated by translation attenuation and transcription attenuation mechanisms. Antibiotic-induced ribosome stalling during translation of an upstream open reading frame in the vmlR leader region prevents formation of an anti-antiterminator structure, leading to the formation of an antiterminator structure that prevents intrinsic termination. Thus, transcription in the presence of antibiotic induces vmlR expression. We also show that NusG-dependent RNA polymerase pausing in the vmlR leader prevents leaky expression in the absence of antibiotic. Furthermore, we demonstrate that induction of VmlR expression by compromised protein synthesis does not require the ability of VmlR to rescue the translational defect, as exemplified by constitutive induction of VmlR by ribosome assembly defects. Rather, the specificity of induction is determined by the antibiotic's ability to stall the ribosome on the regulatory open reading frame located within the vmlR leader. Finally, we demonstrate the involvement of (p)ppGpp-mediated signalling in antibiotic-induced VmlR expression.
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Affiliation(s)
- Hiraku Takada
- Faculty of Life Sciences, Kyoto Sangyo University and Institute for Protein Dynamics, Kamigamo, Motoyama, Kita-ku, Kyoto 603-8555, Japan
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
- Department of Molecular Biology, Umeå University, Building 6K, 6L University Hospital Area, 90187 Umeå, Sweden
| | - Zachary F Mandell
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Helen Yakhnin
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Anastasiya Glazyrina
- Department of Molecular Biology, Umeå University, Building 6K, 6L University Hospital Area, 90187 Umeå, Sweden
| | - Shinobu Chiba
- Faculty of Life Sciences, Kyoto Sangyo University and Institute for Protein Dynamics, Kamigamo, Motoyama, Kita-ku, Kyoto 603-8555, Japan
| | - Tatsuaki Kurata
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Kelvin J Y Wu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Ben I C Tresco
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Andrew G Myers
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Gemma C Aktinson
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Paul Babitzke
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Vasili Hauryliuk
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
- Department of Molecular Biology, Umeå University, Building 6K, 6L University Hospital Area, 90187 Umeå, Sweden
- University of Tartu, Institute of Technology, 50411, Tartu, Estonia
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28
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Kataoka N, Matsutani M, Matsumoto N, Oda M, Mizumachi Y, Ito K, Tanaka S, Kanesaki Y, Yakushi T, Matsushita K. Mutations in degP and spoT Genes Mediate Response to Fermentation Stress in Thermally Adapted Strains of Acetic Acid Bacterium Komagataeibacter medellinensis NBRC 3288. Front Microbiol 2022; 13:802010. [PMID: 35633714 PMCID: PMC9135448 DOI: 10.3389/fmicb.2022.802010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 04/13/2022] [Indexed: 11/30/2022] Open
Abstract
An acetic acid bacterium, Komagataeibacter medellinensis NBRC 3288, was adapted to higher growth temperatures through an experimental evolution approach in acetic acid fermentation conditions, in which the cells grew under high concentrations of ethanol and acetic acid. The thermally adapted strains were shown to exhibit significantly increased growth and fermentation ability, compared to the wild strain, at higher temperatures. Although the wild cells were largely elongated and exhibited a rough cell surface, the adapted strains repressed the elongation and exhibited a smaller cell size and a smoother cell surface than the wild strain. Among the adapted strains, the ITO-1 strain isolated during the initial rounds of adaptation was shown to have three indel mutations in the genes gyrB, degP, and spoT. Among these, two dispensable genes, degP and spoT, were further examined in this study. Rough cell surface morphology related to degP mutation suggested that membrane vesicle-like structures were increased on the cell surface of the wild-type strain but repressed in the ITO-1 strain under high-temperature acetic acid fermentation conditions. The ΔdegP strain could not grow at higher temperatures and accumulated a large amount of membrane vesicles in the culture supernatant when grown even at 30°C, suggesting that the degP mutation is involved in cell surface stability. As the spoT gene of ITO-1 lost a 3′-end of 424 bp, which includes one (Act-4) of the possible two regulatory domains (TGS and Act-4), two spoT mutant strains were created: one (ΔTGSAct) with a drug cassette in between the 5′-half catalytic domain and 3′-half regulatory domains of the gene, and the other (ΔAct-4) in between TGS and Act-4 domains of the regulatory domain. These spoT mutants exhibited different growth responses; ΔTGSAct grew better in both the fermentation and non-fermentation conditions, whereas ΔAct-4 did only under fermentation conditions, such as ITO-1 at higher temperatures. We suggest that cell elongation and/or cell size are largely related to these spoT mutations, which may be involved in fermentation stress and thermotolerance.
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Affiliation(s)
- Naoya Kataoka
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
- Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi, Japan
| | - Minenosuke Matsutani
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
- NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo, Japan
| | - Nami Matsumoto
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Misuzu Oda
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan
| | - Yuki Mizumachi
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Kohei Ito
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan
| | - Shuhei Tanaka
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Yu Kanesaki
- NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo, Japan
- Research Institute of Green Science and Technology, Shizuoka University, Shizuoka, Japan
| | - Toshiharu Yakushi
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
- Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi, Japan
| | - Kazunobu Matsushita
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
- Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi, Japan
- *Correspondence: Kazunobu Matsushita,
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29
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How to save a bacterial ribosome in times of stress. Semin Cell Dev Biol 2022; 136:3-12. [PMID: 35331628 DOI: 10.1016/j.semcdb.2022.03.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/01/2022] [Accepted: 03/11/2022] [Indexed: 11/21/2022]
Abstract
Biogenesis of ribosomes is one of the most cost- and resource-intensive processes in all living cells. In bacteria, ribosome biogenesis is rate-limiting for growth and must be tightly coordinated to yield maximum fitness of the cells. Since bacteria are continuously facing environmental changes and stress conditions, they have developed sophisticated systems to sense and regulate their nutritional status. Amino acid starvation leads to the synthesis and accumulation of the nucleotide-based second messengers ppGpp and pppGpp [(p)ppGpp], which in turn function as central players of a pleiotropic metabolic adaptation mechanism named the stringent response. Here, we review our current knowledge on the multiple roles of (p)ppGpp in the stress-related modulation of the prokaryotic protein biosynthesis machinery with the ribosome as its core constituent. The alarmones ppGpp/pppGpp act as competitors of their GDP/GTP counterparts, to affect a multitude of ribosome-associated P-loop GTPases involved in the translation cycle, ribosome biogenesis and hibernation. A similar mode of inhibition has been found for the GTPases of the proteins involved in the SRP-dependent membrane-targeting machinery present in the periphery of the ribosome. In this sense, during stringent conditions, binding of (p)ppGpp restricts the membrane insertion and secretion of proteins. Altogether, we highlight the enormously resource-intensive stages of ribosome biogenesis as a critical regulatory hub of the stringent response that ultimately tunes the protein synthesis capacity and consequently the survival of the cell.
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30
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Inhibition of SRP-dependent protein secretion by the bacterial alarmone (p)ppGpp. Nat Commun 2022; 13:1069. [PMID: 35217658 PMCID: PMC8881573 DOI: 10.1038/s41467-022-28675-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 02/07/2022] [Indexed: 11/08/2022] Open
Abstract
The stringent response enables bacteria to respond to nutrient limitation and other stress conditions through production of the nucleotide-based second messengers ppGpp and pppGpp, collectively known as (p)ppGpp. Here, we report that (p)ppGpp inhibits the signal recognition particle (SRP)-dependent protein targeting pathway, which is essential for membrane protein biogenesis and protein secretion. More specifically, (p)ppGpp binds to the SRP GTPases Ffh and FtsY, and inhibits the formation of the SRP receptor-targeting complex, which is central for the coordinated binding of the translating ribosome to the SecYEG translocon. Cryo-EM analysis of SRP bound to translating ribosomes suggests that (p)ppGpp may induce a distinct conformational stabilization of the NG domain of Ffh and FtsY in Bacillus subtilis but not in E. coli. Bacterial responses to nutrient limitation and other stress conditions are often modulated by the nucleotide-based second messenger (p)ppGpp. Here, the authors show that (p)ppGpp inhibits the SRP membrane-protein insertion and secretion pathway by binding to GTPases Ffh and FtsY.
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31
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Romand S, Abdelkefi H, Lecampion C, Belaroussi M, Dussenne M, Ksas B, Citerne S, Caius J, D'Alessandro S, Fakhfakh H, Caffarri S, Havaux M, Field B. A guanosine tetraphosphate (ppGpp) mediated brake on photosynthesis is required for acclimation to nitrogen limitation in Arabidopsis. eLife 2022; 11:e75041. [PMID: 35156611 PMCID: PMC8887892 DOI: 10.7554/elife.75041] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
Guanosine pentaphosphate and tetraphosphate (together referred to as ppGpp) are hyperphosphorylated nucleotides found in bacteria and the chloroplasts of plants and algae. In plants and algae artificial ppGpp accumulation can inhibit chloroplast gene expression, and influence photosynthesis, nutrient remobilization, growth, and immunity. However, it is so far unknown whether ppGpp is required for abiotic stress acclimation in plants. Here, we demonstrate that ppGpp biosynthesis is necessary for acclimation to nitrogen starvation in Arabidopsis. We show that ppGpp is required for remodeling the photosynthetic electron transport chain to downregulate photosynthetic activity and for protection against oxidative stress. Furthermore, we demonstrate that ppGpp is required for coupling chloroplastic and nuclear gene expression during nitrogen starvation. Altogether, our work indicates that ppGpp is a pivotal regulator of chloroplast activity for stress acclimation in plants.
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Affiliation(s)
- Shanna Romand
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
| | - Hela Abdelkefi
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
- University of Tunis El Manar, Faculty of Sciences of Tunis, Laboratory of Molecular Genetics, Immunology and BiotechnologyTunisTunisia
| | - Cécile Lecampion
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
| | | | - Melanie Dussenne
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
| | - Brigitte Ksas
- Aix-Marseille University, CEA, CNRS, BIAM, SAVE TeamSaint-Paul-lez-DuranceFrance
| | - Sylvie Citerne
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, INRAE Centre de Versailles-Grignon, Université Paris-SaclayVersaillesFrance
| | - Jose Caius
- Université Paris-Saclay, CNRS, INRAE, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2)OrsayFrance
- Université de Paris, CNRS, INRAE, Institute of Plant Sciences Paris-Saclay (IPS2)OrsayFrance
| | | | - Hatem Fakhfakh
- University of Tunis El Manar, Faculty of Sciences of Tunis, Laboratory of Molecular Genetics, Immunology and BiotechnologyTunisTunisia
- University of Carthage, Faculty of Sciences of BizerteBizerteTunisia
| | - Stefano Caffarri
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
| | - Michel Havaux
- Aix-Marseille University, CEA, CNRS, BIAM, SAVE TeamSaint-Paul-lez-DuranceFrance
| | - Ben Field
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP TeamMarseilleFrance
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A hyperpromiscuous antitoxin protein domain for the neutralization of diverse toxin domains. Proc Natl Acad Sci U S A 2022; 119:2102212119. [PMID: 35121656 PMCID: PMC8832971 DOI: 10.1073/pnas.2102212119] [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] [Accepted: 12/02/2021] [Indexed: 12/20/2022] Open
Abstract
Toxin–antitoxin systems are enigmatic and diverse elements of bacterial and bacteriophage genomes. We have uncovered remarkable versatility in an antitoxin protein domain that has evolved to neutralize dozens of different toxin domains. We find that antitoxins carrying this domain—Panacea—form complexes with their cognate toxins, indicating a direct neutralization mechanism, and that Panacea can be evolved to neutralize a noncognate and nonhomologous toxin with just two amino acid substitutions. This raises the possibility that this domain could be an adaptable universal or semi-universal protein neutralizer with significant biotechnological and medical potential. Toxin–antitoxin (TA) gene pairs are ubiquitous in microbial chromosomal genomes and plasmids as well as temperate bacteriophages. They act as regulatory switches, with the toxin limiting the growth of bacteria and archaea by compromising diverse essential cellular targets and the antitoxin counteracting the toxic effect. To uncover previously uncharted TA diversity across microbes and bacteriophages, we analyzed the conservation of genomic neighborhoods using our computational tool FlaGs (for flanking genes), which allows high-throughput detection of TA-like operons. Focusing on the widespread but poorly experimentally characterized antitoxin domain DUF4065, our in silico analyses indicated that DUF4065-containing proteins serve as broadly distributed antitoxin components in putative TA-like operons with dozens of different toxic domains with multiple different folds. Given the versatility of DUF4065, we have named the domain Panacea (and proteins containing the domain, PanA) after the Greek goddess of universal remedy. We have experimentally validated nine PanA-neutralized TA pairs. While the majority of validated PanA-neutralized toxins act as translation inhibitors or membrane disruptors, a putative nucleotide cyclase toxin from a Burkholderia prophage compromises transcription and translation as well as inducing RelA-dependent accumulation of the nucleotide alarmone (p)ppGpp. We find that Panacea-containing antitoxins form a complex with their diverse cognate toxins, characteristic of the direct neutralization mechanisms employed by Type II TA systems. Finally, through directed evolution, we have selected PanA variants that can neutralize noncognate TA toxins, thus experimentally demonstrating the evolutionary plasticity of this hyperpromiscuous antitoxin domain.
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Strezsak SR, Beuning PJ, Skizim NJ. Versatile separation of nucleotides from bacterial cell lysates using strong anion exchange chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2021; 1188:123044. [PMID: 34864423 DOI: 10.1016/j.jchromb.2021.123044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/08/2021] [Accepted: 11/11/2021] [Indexed: 10/19/2022]
Abstract
Nucleotides exemplify some of the building blocks of life, comprising DNA & RNA, participating in processes such as cell signaling and metabolism, and serving as carriers of metabolic energy. The quantification of these compounds in biological samples is critical for researchers to understand complex systems. Herein, we demonstrate an anion exchange chromatography method utilizing a pH range of 8 to 10, which provides superior resolution and selectivity to previously reported methods and, more importantly, gives the flexibility to shift analyte selectivity if resolution between analytes is not optimal. We have applied the method to study the kinetics of the nucleotide pool in a bacterial cell-free lysate system that is producing RNA. Sample to sample runtimes are less than 18 min and recoveries greater than 96% were observed for all analytes through our methanol quench protocol with day-to-day variabilities less than 5%. This method reliably detects and quantifies all analytes that were expected to be observed in the process and helps lay the groundwork for future nucleotide research.
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Affiliation(s)
- Steven R Strezsak
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115, United States; Greenlight Biosciences, Medford, MA, 02155, United States
| | - Penny J Beuning
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115, United States
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34
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The Stringent Response Inhibits 70S Ribosome Formation in Staphylococcus aureus by Impeding GTPase-Ribosome Interactions. mBio 2021; 12:e0267921. [PMID: 34749534 PMCID: PMC8579695 DOI: 10.1128/mbio.02679-21] [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] [Indexed: 01/16/2023] Open
Abstract
During nutrient limitation, bacteria produce the alarmones (p)ppGpp as effectors of a stress signaling network termed the stringent response. RsgA, RbgA, Era, and HflX are four ribosome-associated GTPases (RA-GTPases) that bind to (p)ppGpp in Staphylococcus aureus. These enzymes are cofactors in ribosome assembly, where they cycle between the ON (GTP-bound) and OFF (GDP-bound) ribosome-associated states. Entry into the OFF state occurs upon hydrolysis of GTP, with GTPase activity increasing substantially upon ribosome association. When bound to (p)ppGpp, GTPase activity is inhibited, reducing 70S ribosome assembly and growth. Here, we determine how (p)ppGpp impacts RA-GTPase-ribosome interactions. We show that RA-GTPases preferentially bind to 5′-diphosphate-containing nucleotides GDP and ppGpp over GTP, which is likely exploited as a regulatory mechanism within the cell to shut down ribosome biogenesis during stress. Stopped-flow fluorescence and association assays reveal that when bound to (p)ppGpp, the association of RA-GTPases to ribosomal subunits is destabilized, both in vitro and within bacterial cells. Consistently, structural analysis of the ppGpp-bound RA-GTPase RsgA reveals an OFF-state conformation similar to the GDP-bound state, with the G2/switch I loop adopting a conformation incompatible with ribosome association. Altogether, we highlight (p)ppGpp-mediated inhibition of RA-GTPases as a major mechanism of stringent response-mediated ribosome assembly and growth control.
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35
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Sun Z, Wu R, Zhao B, Zeinert R, Chien P, You M. Live-Cell Imaging of Guanosine Tetra- and Pentaphosphate (p)ppGpp with RNA-based Fluorescent Sensors*. Angew Chem Int Ed Engl 2021; 60:24070-24074. [PMID: 34487413 PMCID: PMC8545912 DOI: 10.1002/anie.202111170] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Indexed: 11/09/2022]
Abstract
Guanosine tetra- and pentaphosphate, (p)ppGpp, are important alarmone nucleotides that regulate bacterial survival in stressful environment. A direct detection of (p)ppGpp in living cells is critical for our understanding of the mechanism of bacterial stringent response. However, it is still challenging to image cellular (p)ppGpp. Here, we report RNA-based fluorescent sensors for the live-cell imaging of (p)ppGpp. Our sensors are engineered by conjugating a recently identified (p)ppGpp-specific riboswitch with a fluorogenic RNA aptamer, Broccoli. These sensors can be genetically encoded and enable direct monitoring of cellular (p)ppGpp accumulation. Unprecedented information on cell-to-cell variation and cellular dynamics of (p)ppGpp levels is now obtained under different nutritional conditions. These RNA-based sensors can be broadly adapted to study bacterial stringent response.
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Affiliation(s)
- Zhining Sun
- Department of Chemistry, University of Massachusetts, Amherst, USA
| | - Rigumula Wu
- Department of Chemistry, University of Massachusetts, Amherst, USA
| | - Bin Zhao
- Department of Chemistry, University of Massachusetts, Amherst, USA
| | - Rilee Zeinert
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, USA
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, USA
| | - Mingxu You
- Department of Chemistry, University of Massachusetts, Amherst, USA
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36
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Sun Z, Wu R, Zhao B, Zeinert R, Chien P, You M. Live‐Cell Imaging of Guanosine Tetra‐ and Pentaphosphate (p)ppGpp with RNA‐based Fluorescent Sensors**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202111170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Zhining Sun
- Department of Chemistry University of Massachusetts Amherst USA
| | - Rigumula Wu
- Department of Chemistry University of Massachusetts Amherst USA
| | - Bin Zhao
- Department of Chemistry University of Massachusetts Amherst USA
| | - Rilee Zeinert
- Department of Biochemistry and Molecular Biology University of Massachusetts Amherst USA
| | - Peter Chien
- Department of Biochemistry and Molecular Biology University of Massachusetts Amherst USA
| | - Mingxu You
- Department of Chemistry University of Massachusetts Amherst USA
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37
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Lee SO, Xie Q, Fried SD. Optimized Loopable Translation as a Platform for the Synthesis of Repetitive Proteins. ACS CENTRAL SCIENCE 2021; 7:1736-1750. [PMID: 34729417 PMCID: PMC8554844 DOI: 10.1021/acscentsci.1c00574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Indexed: 06/13/2023]
Abstract
The expression of long proteins with repetitive amino acid sequences often presents a challenge in recombinant systems. To overcome this obstacle, we report a genetic construct that circularizes mRNA in vivo by rearranging the topology of a group I self-splicing intron from T4 bacteriophage, thereby enabling "loopable" translation. Using a fluorescence-based assay to probe the translational efficiency of circularized mRNAs, we identify several conditions that optimize protein expression from this system. Our data suggested that translation of circularized mRNAs could be limited primarily by the rate of ribosomal initiation; therefore, using a modified error-prone PCR method, we generated a library that concentrated mutations into the initiation region of circularized mRNA and discovered mutants that generated markedly higher expression levels. Combining our rational improvements with those discovered through directed evolution, we report a loopable translator that achieves protein expression levels within 1.5-fold of the levels of standard vectorial translation. In summary, our work demonstrates loopable translation as a promising platform for the creation of large peptide chains, with potential utility in the development of novel protein materials.
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38
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Kurata T, Brodiazhenko T, Alves Oliveira SR, Roghanian M, Sakaguchi Y, Turnbull KJ, Bulvas O, Takada H, Tamman H, Ainelo A, Pohl R, Rejman D, Tenson T, Suzuki T, Garcia-Pino A, Atkinson GC, Hauryliuk V. RelA-SpoT Homolog toxins pyrophosphorylate the CCA end of tRNA to inhibit protein synthesis. Mol Cell 2021; 81:3160-3170.e9. [PMID: 34174184 DOI: 10.1016/j.molcel.2021.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/28/2021] [Accepted: 06/02/2021] [Indexed: 11/17/2022]
Abstract
RelA-SpoT Homolog (RSH) enzymes control bacterial physiology through synthesis and degradation of the nucleotide alarmone (p)ppGpp. We recently discovered multiple families of small alarmone synthetase (SAS) RSH acting as toxins of toxin-antitoxin (TA) modules, with the FaRel subfamily of toxSAS abrogating bacterial growth by producing an analog of (p)ppGpp, (pp)pApp. Here we probe the mechanism of growth arrest used by four experimentally unexplored subfamilies of toxSAS: FaRel2, PhRel, PhRel2, and CapRel. Surprisingly, all these toxins specifically inhibit protein synthesis. To do so, they transfer a pyrophosphate moiety from ATP to the tRNA 3' CCA. The modification inhibits both tRNA aminoacylation and the sensing of cellular amino acid starvation by the ribosome-associated RSH RelA. Conversely, we show that some small alarmone hydrolase (SAH) RSH enzymes can reverse the pyrophosphorylation of tRNA to counter the growth inhibition by toxSAS. Collectively, we establish RSHs as RNA-modifying enzymes.
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Affiliation(s)
- Tatsuaki Kurata
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden.
| | | | | | - Mohammad Roghanian
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 901 87 Umeå, Sweden; Department of Clinical Microbiology, Rigshospitalet, 2200 Copenhagen, Denmark
| | - Yuriko Sakaguchi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kathryn Jane Turnbull
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 901 87 Umeå, Sweden; Department of Clinical Microbiology, Rigshospitalet, 2200 Copenhagen, Denmark
| | - Ondřej Bulvas
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovonam. 2, 166 10 Prague 6, Czech Republic
| | - Hiraku Takada
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo, Motoyama, Kita-ku, Kyoto 603-8555, Japan
| | - Hedvig Tamman
- Cellular and Molecular Microbiology (CM2), Faculté des Sciences, Université Libre de Bruxelles (ULB), Campus La Plaine, Building BC, Room 1C4203, Boulevard du Triomphe, 1050 Brussels, Belgium
| | - Andres Ainelo
- Cellular and Molecular Microbiology (CM2), Faculté des Sciences, Université Libre de Bruxelles (ULB), Campus La Plaine, Building BC, Room 1C4203, Boulevard du Triomphe, 1050 Brussels, Belgium
| | - Radek Pohl
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovonam. 2, 166 10 Prague 6, Czech Republic
| | - Dominik Rejman
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovonam. 2, 166 10 Prague 6, Czech Republic
| | - Tanel Tenson
- University of Tartu, Institute of Technology, 50411 Tartu, Estonia
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Abel Garcia-Pino
- Cellular and Molecular Microbiology (CM2), Faculté des Sciences, Université Libre de Bruxelles (ULB), Campus La Plaine, Building BC, Room 1C4203, Boulevard du Triomphe, 1050 Brussels, Belgium; WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | | | - Vasili Hauryliuk
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden; University of Tartu, Institute of Technology, 50411 Tartu, Estonia; Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 901 87 Umeå, Sweden.
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Deacylated tRNA Accumulation Is a Trigger for Bacterial Antibiotic Persistence Independent of the Stringent Response. mBio 2021; 12:e0113221. [PMID: 34126764 PMCID: PMC8262941 DOI: 10.1128/mbio.01132-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial antibiotic persistence occurs when bacteria are treated with an antibiotic and the majority of the population rapidly dies off, but a small subpopulation enters into a dormant, persistent state and evades death. Diverse pathways leading to nucleoside triphosphate (NTP) depletion and restricted translation have been implicated in persistence, suggesting alternative redundant routes may exist to initiate persister formation. To investigate the molecular mechanism of one such pathway, functional variants of an essential component of translation (phenylalanyl-tRNA synthetase [PheRS]) were used to study the effects of quality control on antibiotic persistence. Upon amino acid limitation, elevated PheRS quality control led to significant decreases in aminoacylated tRNAPhe accumulation and increased antibiotic persistence. This increase in antibiotic persistence was most pronounced (65-fold higher) when the relA-encoded tRNA-dependent stringent response was inactivated. The increase in persistence with elevated quality control correlated with ∼2-fold increases in the levels of the RNase MazF and the NTPase MazG and a 3-fold reduction in cellular NTP pools. These data reveal a mechanism for persister formation independent of the stringent response where reduced translation capacity, as indicated by reduced levels of aminoacylated tRNA, is accompanied by active reduction of cellular NTP pools which in turn triggers antibiotic persistence. IMPORTANCE Bacterial antibiotic persistence is a transient physiological state wherein cells become dormant and thereby evade being killed by antibiotics. Once the antibiotic is removed, bacterial persisters are able to resuscitate and repopulate. It is thought that antibiotic bacterial persisters may cause reoccurring infections in the clinical setting. The molecular triggers and pathways that cause bacteria to enter into the persister state are not fully understood. Our results suggest that accumulation of deacylated tRNA is a trigger for antibiotic persistence independent of the RelA-dependent stringent response, a pathway thought to be required for persistence in many organisms. Overall, this provides a mechanism where changes in translation quality control in response to physiological cues can directly modulate bacterial persistence.
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40
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Oswald J, Njenga R, Natriashvili A, Sarmah P, Koch HG. The Dynamic SecYEG Translocon. Front Mol Biosci 2021; 8:664241. [PMID: 33937339 PMCID: PMC8082313 DOI: 10.3389/fmolb.2021.664241] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/24/2021] [Indexed: 12/13/2022] Open
Abstract
The spatial and temporal coordination of protein transport is an essential cornerstone of the bacterial adaptation to different environmental conditions. By adjusting the protein composition of extra-cytosolic compartments, like the inner and outer membranes or the periplasmic space, protein transport mechanisms help shaping protein homeostasis in response to various metabolic cues. The universally conserved SecYEG translocon acts at the center of bacterial protein transport and mediates the translocation of newly synthesized proteins into and across the cytoplasmic membrane. The ability of the SecYEG translocon to transport an enormous variety of different substrates is in part determined by its ability to interact with multiple targeting factors, chaperones and accessory proteins. These interactions are crucial for the assisted passage of newly synthesized proteins from the cytosol into the different bacterial compartments. In this review, we summarize the current knowledge about SecYEG-mediated protein transport, primarily in the model organism Escherichia coli, and describe the dynamic interaction of the SecYEG translocon with its multiple partner proteins. We furthermore highlight how protein transport is regulated and explore recent developments in using the SecYEG translocon as an antimicrobial target.
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Affiliation(s)
- Julia Oswald
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Robert Njenga
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Ana Natriashvili
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Pinku Sarmah
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany
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41
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Takada H, Roghanian M, Caballero-Montes J, Van Nerom K, Jimmy S, Kudrin P, Trebini F, Murayama R, Akanuma G, Garcia-Pino A, Hauryliuk V. Ribosome association primes the stringent factor Rel for tRNA-dependent locking in the A-site and activation of (p)ppGpp synthesis. Nucleic Acids Res 2021; 49:444-457. [PMID: 33330919 PMCID: PMC7797070 DOI: 10.1093/nar/gkaa1187] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 11/17/2022] Open
Abstract
In the Gram-positive Firmicute bacterium Bacillus subtilis, amino acid starvation induces synthesis of the alarmone (p)ppGpp by the RelA/SpoT Homolog factor Rel. This bifunctional enzyme is capable of both synthesizing and hydrolysing (p)ppGpp. To detect amino acid deficiency, Rel monitors the aminoacylation status of the ribosomal A-site tRNA by directly inspecting the tRNA’s CCA end. Here we dissect the molecular mechanism of B. subtilis Rel. Off the ribosome, Rel predominantly assumes a ‘closed’ conformation with dominant (p)ppGpp hydrolysis activity. This state does not specifically select deacylated tRNA since the interaction is only moderately affected by tRNA aminoacylation. Once bound to the vacant ribosomal A-site, Rel assumes an ‘open’ conformation, which primes its TGS and Helical domains for specific recognition and stabilization of cognate deacylated tRNA on the ribosome. The tRNA locks Rel on the ribosome in a hyperactivated state that processively synthesises (p)ppGpp while the hydrolysis is suppressed. In stark contrast to non-specific tRNA interactions off the ribosome, tRNA-dependent Rel locking on the ribosome and activation of (p)ppGpp synthesis are highly specific and completely abrogated by tRNA aminoacylation. Binding pppGpp to a dedicated allosteric site located in the N-terminal catalytic domain region of the enzyme further enhances its synthetase activity.
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Affiliation(s)
- Hiraku Takada
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 87 Umeå, Sweden
| | - Mohammad Roghanian
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 87 Umeå, Sweden
| | - Julien Caballero-Montes
- Cellular and Molecular Microbiology, Faculté des Sciences, Université Libre de Bruxelles (ULB), Building BC, Room 1C4 203, Boulevard du Triomphe, 1050 Brussels, Belgium
| | - Katleen Van Nerom
- Cellular and Molecular Microbiology, Faculté des Sciences, Université Libre de Bruxelles (ULB), Building BC, Room 1C4 203, Boulevard du Triomphe, 1050 Brussels, Belgium
| | - Steffi Jimmy
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 87 Umeå, Sweden
| | - Pavel Kudrin
- University of Tartu, Institute of Technology, 50411 Tartu, Estonia
| | - Fabio Trebini
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Rikinori Murayama
- Akita Prefectural Research Center for Public Health and Environment, 6-6 Senshu-Kubotamachi, Akita, 010-0874, Japan
| | - Genki Akanuma
- Department of Life Science, Graduate School of Science, Gakushuin University, Tokyo, Japan
| | - Abel Garcia-Pino
- Cellular and Molecular Microbiology, Faculté des Sciences, Université Libre de Bruxelles (ULB), Building BC, Room 1C4 203, Boulevard du Triomphe, 1050 Brussels, Belgium.,WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Vasili Hauryliuk
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 87 Umeå, Sweden.,University of Tartu, Institute of Technology, 50411 Tartu, Estonia
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42
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Riber L, Løbner‐Olesen A. Inhibition of Escherichia coli chromosome replication by rifampicin treatment or during the stringent response is overcome by de novo DnaA protein synthesis. Mol Microbiol 2020; 114:906-919. [PMID: 32458540 PMCID: PMC7818497 DOI: 10.1111/mmi.14531] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/13/2020] [Accepted: 05/16/2020] [Indexed: 12/15/2022]
Abstract
Initiation of Escherichia coli chromosome replication is controlled by the DnaA initiator protein. Both rifampicin-mediated inhibition of transcription and ppGpp-induced changes in global transcription stops replication at the level of initiation. Here, we show that continued DnaA protein synthesis allows for replication initiation both during the rifampicin treatment and during the stringent response when the ppGpp level is high. A reduction in or cessation of de novo DnaA synthesis, therefore, causes the initiation arrest in both cases. In accordance with this, inhibition of translation with chloramphenicol also stops initiations. The initiation arrest caused by rifampicin was faster than that caused by chloramphenicol, despite of the latter inhibiting DnaA accumulation immediately. During chloramphenicol treatment transcription is still ongoing and we suggest that transcriptional events in or near the origin, that is, transcriptional activation, can allow for a few extra initiations when DnaA becomes limiting. We suggest, for both rifampicin treated cells and for cells accumulating ppGpp, that a turn-off of initiation from oriC requires a stop in de novo DnaA synthesis and that an additional lack of transcriptional activation enhances this process, that is, leads to a faster initiation stop.
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Affiliation(s)
- Leise Riber
- Department of BiologyUniversity of CopenhagenCopenhagenDenmark
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43
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Shyp V, Dubey BN, Böhm R, Hartl J, Nesper J, Vorholt JA, Hiller S, Schirmer T, Jenal U. Reciprocal growth control by competitive binding of nucleotide second messengers to a metabolic switch in Caulobacter crescentus. Nat Microbiol 2020; 6:59-72. [PMID: 33168988 DOI: 10.1038/s41564-020-00809-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 10/02/2020] [Indexed: 12/13/2022]
Abstract
Bacteria use small signalling molecules such as (p)ppGpp or c-di-GMP to tune their physiology in response to environmental changes. It remains unclear whether these regulatory networks operate independently or whether they interact to optimize bacterial growth and survival. We report that (p)ppGpp and c-di-GMP reciprocally regulate the growth of Caulobacter crescentus by converging on a single small-molecule-binding protein, SmbA. While c-di-GMP binding inhibits SmbA, (p)ppGpp competes for the same binding site to sustain SmbA activity. We demonstrate that (p)ppGpp specifically promotes Caulobacter growth on glucose, whereas c-di-GMP inhibits glucose consumption. We find that SmbA contributes to this metabolic switch and promotes growth on glucose by quenching the associated redox stress. The identification of an effector protein that acts as a central regulatory hub for two global second messengers opens up future studies on specific crosstalk between small-molecule-based regulatory networks.
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Affiliation(s)
| | | | - Raphael Böhm
- Biozentrum, University of Basel, Basel, Switzerland
| | - Johannes Hartl
- Institute of Microbiology, ETH Zurich, Zürich, Switzerland
| | - Jutta Nesper
- Biozentrum, University of Basel, Basel, Switzerland
| | | | | | | | - Urs Jenal
- Biozentrum, University of Basel, Basel, Switzerland.
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44
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Myers AR, Thistle DP, Ross W, Gourse RL. Guanosine Tetraphosphate Has a Similar Affinity for Each of Its Two Binding Sites on Escherichia coli RNA Polymerase. Front Microbiol 2020; 11:587098. [PMID: 33250875 PMCID: PMC7676912 DOI: 10.3389/fmicb.2020.587098] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/06/2020] [Indexed: 11/13/2022] Open
Abstract
During nutrient deprivation, the bacterial cell undergoes a stress response known as the stringent response. This response is characterized by induction of the nucleotide derivative guanosine tetraphosphate (ppGpp) that dramatically modulates the cell's transcriptome. In Escherichia coli, ppGpp regulates transcription of as many as 750 genes within 5 min of induction by binding directly to RNA polymerase (RNAP) at two sites ~60 Å apart. One proposal for the presence of two sites is that they have different affinities for ppGpp, expanding the dynamic range over which ppGpp acts. We show here, primarily using the Differential Radial Capillary Action of Ligand Assay (DRaCALA), that ppGpp has a similar affinity for each site, contradicting the proposal. Because the ppGpp binding sites are formed by interactions of the β' subunit of RNAP with two small protein factors, the ω subunit of RNAP which contributes to Site 1 and the transcription factor DksA which contributes to Site 2, variation in the concentrations of ω or DksA potentially could differentially regulate ppGpp occupancy of the two sites. It was shown previously that DksA varies little at different growth rates or growth phases, but little is known about variation of the ω concentration. Therefore, we raised an anti-ω antibody and performed Western blots at different times in growth and during a stringent response. We show here that ω, like DksA, changes little with growth conditions. Together, our data suggest that the two ppGpp binding sites fill in parallel, and occupancy with changing nutritional conditions is determined by variation in the ppGpp concentration, not by variation in ω or DksA.
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Affiliation(s)
| | | | | | - Richard L. Gourse
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
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45
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Pletnev P, Pupov D, Pshanichnaya L, Esyunina D, Petushkov I, Nesterchuk M, Osterman I, Rubtsova M, Mardanov A, Ravin N, Sergiev P, Kulbachinskiy A, Dontsova O. Rewiring of growth-dependent transcription regulation by a point mutation in region 1.1 of the housekeeping σ factor. Nucleic Acids Res 2020; 48:10802-10819. [PMID: 32997144 PMCID: PMC7641759 DOI: 10.1093/nar/gkaa798] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 09/09/2020] [Accepted: 09/12/2020] [Indexed: 01/24/2023] Open
Abstract
In bacteria, rapid adaptation to changing environmental conditions depends on the interplay between housekeeping and alternative σ factors, responsible for transcription of specific regulons by RNA polymerase (RNAP). In comparison with alternative σ factors, primary σs contain poorly conserved region 1.1, whose functions in transcription are only partially understood. We found that a single mutation in region 1.1 in Escherichia coli σ70 rewires transcription regulation during cell growth resulting in profound phenotypic changes. Despite its destabilizing effect on promoter complexes, this mutation increases the activity of rRNA promoters and also decreases RNAP sensitivity to the major regulator of stringent response DksA. Using total RNA sequencing combined with single-cell analysis of gene expression we showed that changes in region 1.1 disrupt the balance between the "greed" and "fear" strategies thus making the cells more susceptible to environmental threats and antibiotics. Our results reveal an unexpected role of σ region 1.1 in growth-dependent transcription regulation and suggest that changes in this region may facilitate rapid switching of RNAP properties in evolving bacterial populations.
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Affiliation(s)
- Philipp Pletnev
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia
| | - Danil Pupov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow,123182, Russia
| | | | - Daria Esyunina
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow,123182, Russia
| | - Ivan Petushkov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow,123182, Russia
| | - Mikhail Nesterchuk
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia
| | - Ilya Osterman
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia
| | - Maria Rubtsova
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia
| | - Andrey Mardanov
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Nikolai Ravin
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Petr Sergiev
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia.,Institute of Functional Genomics, Lomonosov Moscow State University, Moscow 119992, Russia
| | - Andrey Kulbachinskiy
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow,123182, Russia
| | - Olga Dontsova
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119992, Russia.,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region 143028, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia
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46
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Imholz NCE, Noga MJ, van den Broek NJF, Bokinsky G. Calibrating the Bacterial Growth Rate Speedometer: A Re-evaluation of the Relationship Between Basal ppGpp, Growth, and RNA Synthesis in Escherichia coli. Front Microbiol 2020; 11:574872. [PMID: 33042085 PMCID: PMC7527470 DOI: 10.3389/fmicb.2020.574872] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 08/25/2020] [Indexed: 01/20/2023] Open
Abstract
The molecule guanosine tetraphophosphate (ppGpp) is most commonly considered an alarmone produced during acute stress. However, ppGpp is also present at low concentrations during steady-state growth. Whether ppGpp controls the same cellular targets at both low and high concentrations remains an open question and is vital for understanding growth rate regulation. It is widely assumed that basal ppGpp concentrations vary inversely with growth rate, and that the main function of basal ppGpp is to regulate transcription of ribosomal RNA in response to environmental conditions. Unfortunately, studies to confirm this relationship and to define regulatory targets of basal ppGpp are limited by difficulties in quantifying basal ppGpp. In this Perspective we compare reported concentrations of basal ppGpp in E. coli and quantify ppGpp within several strains using a recently developed analytical method. We find that although the inverse correlation between ppGpp and growth rate is robust across strains and analytical methods, absolute ppGpp concentrations do not absolutely determine RNA synthesis rates. In addition, we investigated the consequences of two separate RNA polymerase mutations that each individually reduce (but do not abolish) sensitivity to ppGpp and find that the relationship between ppGpp, growth rate, and RNA content of single-site mutants remains unaffected. Both literature and our new data suggest that environmental conditions may be communicated to RNA polymerase via an additional regulator. We conclude that basal ppGpp is one of potentially several agents controlling ribosome abundance and DNA replication initiation, but that evidence for additional roles in controlling macromolecular synthesis requires further study.
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Affiliation(s)
- Nicole C E Imholz
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands
| | - Marek J Noga
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands
| | - Niels J F van den Broek
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands
| | - Gregory Bokinsky
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands
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47
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The (p)ppGpp Synthetase RSH Mediates Stationary-Phase Onset and Antibiotic Stress Survival in Clostridioides difficile. J Bacteriol 2020; 202:JB.00377-20. [PMID: 32661079 DOI: 10.1128/jb.00377-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/09/2020] [Indexed: 12/31/2022] Open
Abstract
The human pathogen Clostridioides difficile is increasingly tolerant of multiple antibiotics and causes infections with a high rate of recurrence, creating an urgent need for new preventative and therapeutic strategies. The stringent response, a universal bacterial response to extracellular stress, governs antibiotic survival and pathogenesis in diverse organisms but has not previously been characterized in C. difficile Here, we report that the C. difficile (p)ppGpp synthetase RSH is incapable of utilizing GTP or GMP as a substrate but readily synthesizes ppGpp from GDP. The enzyme also utilizes many structurally diverse metal cofactors for reaction catalysis and remains functionally stable at a wide range of environmental pHs. Transcription of rsh is stimulated by stationary-phase onset and by exposure to the antibiotics clindamycin and metronidazole. Chemical inhibition of RSH by the ppGpp analog relacin increases antibiotic susceptibility in epidemic C. difficile R20291, indicating that RSH inhibitors may be a viable strategy for drug development against C. difficile infection. Finally, transcriptional suppression of rsh also increases bacterial antibiotic susceptibility, suggesting that RSH contributes to C. difficile antibiotic tolerance and survival.IMPORTANCE Clostridioides difficile infection (CDI) is an urgent public health threat with a high recurrence rate, in part because the causative bacterium has a high rate of antibiotic survival. The (p)ppGpp-mediated bacterial stringent response plays a role in antibiotic tolerance in diverse pathogens and is a potential target for development of new antimicrobials because the enzymes that metabolize (p)ppGpp have no mammalian homologs. We report that stationary-phase onset and antibiotics induce expression of the clostridial ppGpp synthetase RSH and that both chemical inhibition and translational suppression of RSH increase C. difficile antibiotic susceptibility. This demonstrates that development of RSH inhibitors to serve as adjuvants to antibiotic therapy is a potential approach for the development of new strategies to combat CDI.
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48
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Steinchen W, Zegarra V, Bange G. (p)ppGpp: Magic Modulators of Bacterial Physiology and Metabolism. Front Microbiol 2020; 11:2072. [PMID: 33013756 PMCID: PMC7504894 DOI: 10.3389/fmicb.2020.02072] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/06/2020] [Indexed: 01/21/2023] Open
Abstract
When bacteria experience growth-limiting environmental conditions, the synthesis of the hyperphosphorylated guanosine derivatives (p)ppGpp is induced by enzymes of the RelA/SpoT homology (RSH)-type protein family. High levels of (p)ppGpp induce a process called "stringent response", a major cellular reprogramming during which ribosomal RNA (rRNA) and transfer RNA (tRNA) synthesis is downregulated, stress-related genes upregulated, messenger RNA (mRNA) stability and translation altered, and allocation of scarce resources optimized. The (p)ppGpp-mediated stringent response is thus often regarded as an all-or-nothing paradigm induced by stress. Over the past decades, several binding partners of (p)ppGpp have been uncovered displaying dissociation constants from below one micromolar to more than one millimolar and thus coincide with the accepted intracellular concentrations of (p)ppGpp under non-stringent (basal levels) and stringent conditions. This suggests that the ability of (p)ppGpp to modulate target proteins or processes would be better characterized as an unceasing continuum over a concentration range instead of being an abrupt switch of biochemical processes under specific conditions. We analyzed the reported binding affinities of (p)ppGpp targets and depicted a scheme for prioritization of modulation by (p)ppGpp. In this ranking, many enzymes of e.g., nucleotide metabolism are among the first targets to be affected by rising (p)ppGpp while more fundamental processes such as DNA replication are among the last. This preference should be part of (p)ppGpp's "magic" in the adaptation of microorganisms while still maintaining their potential for outgrowth once a stressful condition is overcome.
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Affiliation(s)
- Wieland Steinchen
- Department of Chemistry, Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | | | - Gert Bange
- Department of Chemistry, Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
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49
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Fung DK, Yang J, Stevenson DM, Amador-Noguez D, Wang JD. Small Alarmone Synthetase SasA Expression Leads to Concomitant Accumulation of pGpp, ppApp, and AppppA in Bacillus subtilis. Front Microbiol 2020; 11:2083. [PMID: 32983059 PMCID: PMC7492591 DOI: 10.3389/fmicb.2020.02083] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 08/07/2020] [Indexed: 12/18/2022] Open
Abstract
(p)ppGpp is a highly conserved bacterial alarmone which regulates many aspects of cellular physiology and metabolism. In Gram-positive bacteria such as B. subtilis, cellular (p)ppGpp level is determined by the bifunctional (p)ppGpp synthetase/hydrolase RelA and two small alarmone synthetases (SASs) YjbM (SasB) and YwaC (SasA). However, it is less clear whether these enzymes are also involved in regulation of alarmones outside of (p)ppGpp. Here we developed an improved LC-MS-based method to detect a broad spectrum of metabolites and alarmones from bacterial cultures with high efficiency. By characterizing the metabolomic signatures of SasA expressing B. subtilis, we identified strong accumulation of the (p)ppGpp analog pGpp, as well as accumulation of ppApp and AppppA. The induced accumulation of these alarmones is abolished in the catalytically dead sasA mutant, suggesting that it is a consequence of SasA synthetase activity. In addition, we also identified depletion of specific purine nucleotides and their precursors including IMP precursors FGAR, SAICAR and AICAR (ZMP), as well as GTP and GDP. Furthermore, we also revealed depletion of multiple pyrimidine precursors such as orotate and orotidine 5′-phosphate. Taken together, our work shows that induction of a single (p)ppGpp synthetase can cause concomitant accumulation and potential regulatory interplay of multiple alarmones.
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Affiliation(s)
- Danny K Fung
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jin Yang
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - David M Stevenson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jue D Wang
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
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50
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Sinha AK, Løbner-Olesen A, Riber L. Bacterial Chromosome Replication and DNA Repair During the Stringent Response. Front Microbiol 2020; 11:582113. [PMID: 32983079 PMCID: PMC7483579 DOI: 10.3389/fmicb.2020.582113] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 08/13/2020] [Indexed: 01/23/2023] Open
Abstract
The stringent response regulates bacterial growth rate and is important for cell survival under changing environmental conditions. The effect of the stringent response is pleiotropic, affecting almost all biological processes in the cell including transcriptional downregulation of genes involved in stable RNA synthesis, DNA replication, and metabolic pathways, as well as the upregulation of stress-related genes. In this Review, we discuss how the stringent response affects chromosome replication and DNA repair activities in bacteria. Importantly, we address how accumulation of (p)ppGpp during the stringent response shuts down chromosome replication using highly different strategies in the evolutionary distant Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. Interestingly, (p)ppGpp-mediated replication inhibition occurs downstream of the origin in B. subtilis, whereas replication inhibition in E. coli takes place at the initiation level, suggesting that stringent cell cycle arrest acts at different phases of the replication cycle between E. coli and B. subtilis. Furthermore, we address the role of (p)ppGpp in facilitating DNA repair activities and cell survival during exposure to UV and other DNA damaging agents. In particular, (p)ppGpp seems to stimulate the efficiency of nucleotide excision repair (NER)-dependent repair of DNA lesions. Finally, we discuss whether (p)ppGpp-mediated cell survival during DNA damage is related to the ability of (p)ppGpp accumulation to inhibit chromosome replication.
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