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Tu Z, Stevenson DM, McCaslin D, Amador-Noguez D, Huynh TN. The role of Listeria monocytogenes PstA in β-lactam resistance requires the cytochrome bd oxidase activity. J Bacteriol 2024; 206:e0013024. [PMID: 38995039 PMCID: PMC11340317 DOI: 10.1128/jb.00130-24] [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: 03/29/2024] [Accepted: 06/13/2024] [Indexed: 07/13/2024] Open
Abstract
c-di-AMP is an essential second messenger that binds and regulates several proteins of different functions within bacterial cells. Among those, PstA is a structurally conserved c-di-AMP-binding protein, but its function is largely unknown. PstA is structurally similar to PII signal transduction proteins, although it specifically binds c-di-AMP rather than other PII ligands such as ATP and α-ketoglutarate. In Listeria monocytogenes, we found that PstA increases β-lactam susceptibility at normal and low c-di-AMP levels, but increases β-lactam resistance upon c-di-AMP accumulation. Examining a PstA mutant defective for c-di-AMP binding, we found the apo form of PstA to be toxic for β-lactam resistance, and the c-di-AMP-bound form to be beneficial. Intriguingly, a role for PstA in β-lactam resistance is only prominent in aerobic cultures, and largely diminished under hypoxic conditions, suggesting that PstA function is linked to aerobic metabolism. However, PstA does not control aerobic growth rate, and has a modest influence on the tricarboxylic acid cycle and membrane potential-an indicator of cellular respiration. The regulatory role of PstA in β-lactam resistance is unrelated to reactive oxygen species or oxidative stress. Interestingly, during aerobic growth, PstA function requires the cytochrome bd oxidase (CydAB), a component of the respiratory electron transport chain. The requirement for CydAB might be related to its function in maintaining a membrane potential, or redox stress response activities. Altogether, we propose a model in which apo-PstA diminishes β-lactam resistance by interacting with an effector protein, and this activity can be countered by c-di-AMP binding or a by-product of redox stress. IMPORTANCE PstA is a structurally conserved c-di-AMP-binding protein that is broadly present among Firmicutes bacteria. Furthermore, PstA binds c-di-AMP at high affinity and specificity, indicating an important role in the c-di-AMP signaling network. However, the molecular function of PstA remains elusive. Our findings reveal contrasting roles of PstA in β-lactam resistance depending on c-di-AMP-binding status. We also define physiological conditions for PstA function during aerobic growth. Future efforts can exploit these conditions to identify PstA interaction partners under β-lactam stress.
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Affiliation(s)
- Zepeng Tu
- Food Science Department, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - David M. Stevenson
- Department of Bacteriology, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Darrel McCaslin
- Biophysics Instrumentation Facility, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - TuAnh N. Huynh
- Food Science Department, University of Wisconsin—Madison, Madison, Wisconsin, USA
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2
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Warneke R, Herzberg C, Weiß M, Schramm T, Hertel D, Link H, Stülke J. DarA-the central processing unit for the integration of osmotic with potassium and amino acid homeostasis in Bacillus subtilis. J Bacteriol 2024; 206:e0019024. [PMID: 38832794 PMCID: PMC11270874 DOI: 10.1128/jb.00190-24] [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: 05/01/2024] [Accepted: 05/08/2024] [Indexed: 06/05/2024] Open
Abstract
Cyclic di-adenosine monophosphate (c-di-AMP) is a second messenger involved in diverse metabolic processes including osmolyte uptake, cell wall homeostasis, as well as antibiotic and heat resistance. This study investigates the role of the c-di-AMP receptor protein DarA in the osmotic stress response in Bacillus subtilis. Through a series of experiments, we demonstrate that DarA plays a central role in the cellular response to osmotic fluctuations. Our findings show that DarA becomes essential under extreme potassium limitation as well as upon salt stress, highlighting its significance in mediating osmotic stress adaptation. Suppressor screens with darA mutants reveal compensatory mechanisms involving the accumulation of osmoprotectants, particularly potassium and citrulline. Mutations affecting various metabolic pathways, including the citric acid cycle as well as glutamate and arginine biosynthesis, indicate a complex interplay between the osmotic stress response and metabolic regulation. In addition, the growth defects of the darA mutant during potassium starvation and salt stress in a strain lacking the high-affinity potassium uptake systems KimA and KtrAB can be rescued by increased affinity of the remaining potassium channel KtrCD or by increased expression of ktrD, thus resulting in increased potassium uptake. Finally, the darA mutant can respond to salt stress by the increased expression of MleN , which can export sodium ions.IMPORTANCEEnvironmental bacteria are exposed to rapidly changing osmotic conditions making an effective adaptation to these changes crucial for the survival of the cells. In Gram-positive bacteria, the second messenger cyclic di-AMP plays a key role in this adaptation by controlling (i) the influx of physiologically compatible organic osmolytes and (ii) the biosynthesis of such osmolytes. In several bacteria, cyclic di-adenosine monophosphate (c-di-AMP) can bind to a signal transduction protein, called DarA, in Bacillus subtilis. So far, no function for DarA has been discovered in any organism. We have identified osmotically challenging conditions that make DarA essential and have identified suppressor mutations that help the bacteria to adapt to those conditions. Our results indicate that DarA is a central component in the integration of osmotic stress with the synthesis of compatible amino acid osmolytes and with the homeostasis of potassium, the first response to osmotic stress.
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Affiliation(s)
- Robert Warneke
- Department of General Microbiology, GZMB, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Christina Herzberg
- Department of General Microbiology, GZMB, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Martin Weiß
- Department of General Microbiology, GZMB, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Thorben Schramm
- Interfaculty Institute for Microbiology and Infection Medicine, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Dietrich Hertel
- Department of Plant Ecology and Ecosystems Research, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Hannes Link
- Interfaculty Institute for Microbiology and Infection Medicine, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Jörg Stülke
- Interfaculty Institute for Microbiology and Infection Medicine, Eberhard Karls Universität Tübingen, Tübingen, Germany
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3
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Foster AJ, van den Noort M, Poolman B. Bacterial cell volume regulation and the importance of cyclic di-AMP. Microbiol Mol Biol Rev 2024; 88:e0018123. [PMID: 38856222 PMCID: PMC11332354 DOI: 10.1128/mmbr.00181-23] [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] [Indexed: 06/11/2024] Open
Abstract
SUMMARYNucleotide-derived second messengers are present in all domains of life. In prokaryotes, most of their functionality is associated with general lifestyle and metabolic adaptations, often in response to environmental fluctuations of physical parameters. In the last two decades, cyclic di-AMP has emerged as an important signaling nucleotide in many prokaryotic lineages, including Firmicutes, Actinobacteria, and Cyanobacteria. Its importance is highlighted by the fact that both the lack and overproduction of cyclic di-AMP affect viability of prokaryotes that utilize cyclic di-AMP, and that it generates a strong innate immune response in eukaryotes. In bacteria that produce the second messenger, most molecular targets of cyclic di-AMP are associated with cell volume control. Besides, other evidence links the second messenger to cell wall remodeling, DNA damage repair, sporulation, central metabolism, and the regulation of glycogen turnover. In this review, we take a biochemical, quantitative approach to address the main cellular processes that are directly regulated by cyclic di-AMP and show that these processes are very connected and require regulation of a similar set of proteins to which cyclic di-AMP binds. Altogether, we argue that cyclic di-AMP is a master regulator of cell volume and that other cellular processes can be connected with cyclic di-AMP through this core function. We further highlight important directions in which the cyclic di-AMP field has to develop to gain a full understanding of the cyclic di-AMP signaling network and why some processes are regulated, while others are not.
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Affiliation(s)
- Alexander J. Foster
- Department of Biochemistry, Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Marco van den Noort
- Department of Biochemistry, Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
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4
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Pedraza-Reyes M, Abundiz-Yañez K, Rangel-Mendoza A, Martínez LE, Barajas-Ornelas RC, Cuéllar-Cruz M, Leyva-Sánchez HC, Ayala-García VM, Valenzuela-García LI, Robleto EA. Bacillus subtilis stress-associated mutagenesis and developmental DNA repair. Microbiol Mol Biol Rev 2024; 88:e0015823. [PMID: 38551349 PMCID: PMC11332352 DOI: 10.1128/mmbr.00158-23] [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] [Indexed: 04/04/2024] Open
Abstract
SUMMARYThe metabolic conditions that prevail during bacterial growth have evolved with the faithful operation of repair systems that recognize and eliminate DNA lesions caused by intracellular and exogenous agents. This idea is supported by the low rate of spontaneous mutations (10-9) that occur in replicating cells, maintaining genome integrity. In contrast, when growth and/or replication cease, bacteria frequently process DNA lesions in an error-prone manner. DNA repairs provide cells with the tools needed for maintaining homeostasis during stressful conditions and depend on the developmental context in which repair events occur. Thus, different physiological scenarios can be anticipated. In nutritionally stressed bacteria, different components of the base excision repair pathway may process damaged DNA in an error-prone approach, promoting genetic variability. Interestingly, suppressing the mismatch repair machinery and activating specific DNA glycosylases promote stationary-phase mutations. Current evidence also suggests that in resting cells, coupling repair processes to actively transcribed genes may promote multiple genetic transactions that are advantageous for stressed cells. DNA repair during sporulation is of interest as a model to understand how transcriptional processes influence the formation of mutations in conditions where replication is halted. Current reports indicate that transcriptional coupling repair-dependent and -independent processes operate in differentiating cells to process spontaneous and induced DNA damage and that error-prone synthesis of DNA is involved in these events. These and other noncanonical ways of DNA repair that contribute to mutagenesis, survival, and evolution are reviewed in this manuscript.
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Affiliation(s)
- Mario Pedraza-Reyes
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Karen Abundiz-Yañez
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Alejandra Rangel-Mendoza
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Lissett E. Martínez
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Rocío C. Barajas-Ornelas
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | - Mayra Cuéllar-Cruz
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, Guanajuato, Mexico
| | | | | | - Luz I. Valenzuela-García
- Department of Sustainable Engineering, Advanced Materials Research Center (CIMAV), Arroyo Seco, Durango, Mexico
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Brissac T, Guyonnet C, Sadouni A, Hernández-Montoya A, Jacquemet E, Legendre R, Sismeiro O, Trieu-Cuot P, Lanotte P, Tazi A, Firon A. Coordinated regulation of osmotic imbalance by c-di-AMP shapes ß-lactam tolerance in Group B Streptococcus. MICROLIFE 2024; 5:uqae014. [PMID: 38993744 PMCID: PMC11238645 DOI: 10.1093/femsml/uqae014] [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: 05/06/2024] [Revised: 06/03/2024] [Accepted: 06/11/2024] [Indexed: 07/13/2024]
Abstract
Streptococcus agalactiae is among the few pathogens that have not developed resistance to ß-lactam antibiotics despite decades of clinical use. The molecular basis of this long-lasting susceptibility has not been investigated, and it is not known whether specific mechanisms constrain the emergence of resistance. In this study, we first report ß-lactam tolerance due to the inactivation of the c-di-AMP phosphodiesterase GdpP. Mechanistically, tolerance depends on antagonistic regulation by the repressor BusR, which is activated by c-di-AMP and negatively regulates ß-lactam susceptibility through the BusAB osmolyte transporter and the AmaP/Asp23/GlsB cell envelope stress complex. The BusR transcriptional response is synergistic with the simultaneous allosteric inhibition of potassium and osmolyte transporters by c-di-AMP, which individually contribute to low-level ß-lactam tolerance. Genome-wide transposon mutagenesis confirms the role of GdpP and highlights functional interactions between a lysozyme-like hydrolase, the KhpAB RNA chaperone and the protein S immunomodulator in the response of GBS to ß-lactam. Overall, we demonstrate that c-di-AMP acts as a turgor pressure rheostat, coordinating an integrated response at the transcriptional and post-translational levels to cell wall weakening caused by ß-lactam activity, and reveal additional mechanisms that could foster resistance.
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Affiliation(s)
- Terry Brissac
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Cécile Guyonnet
- Université Paris Cité, Institut Cochin, Institut National de la Santé et de la Recherche Médicale U1016, Centre National de la Recherche Scientifique UMR8104, Team Bacteria and Perinatality, 75015, Paris, France
- Department of Bacteriology, French National Reference Center for Streptococci, Assistance Publique-Hôpitaux de Paris Hôpitaux Universitaires Paris Centre, Hôpital Cochin, 75005, Paris, France
- Fédération Hospitalo-Universitaire Fighting Prematurity, 75005, Paris, France
| | - Aymane Sadouni
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Ariadna Hernández-Montoya
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Elise Jacquemet
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, 75015 Paris, France
| | - Rachel Legendre
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, 75015 Paris, France
| | - Odile Sismeiro
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Patrick Trieu-Cuot
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Philippe Lanotte
- Université de Tours, INRAE, UMR 1282 ISP, 3700, Tours, France
- CHRU de Tours, Service de Bactériologie-Virologie, 37044, Tours, France
| | - Asmaa Tazi
- Université Paris Cité, Institut Cochin, Institut National de la Santé et de la Recherche Médicale U1016, Centre National de la Recherche Scientifique UMR8104, Team Bacteria and Perinatality, 75015, Paris, France
- Department of Bacteriology, French National Reference Center for Streptococci, Assistance Publique-Hôpitaux de Paris Hôpitaux Universitaires Paris Centre, Hôpital Cochin, 75005, Paris, France
- Fédération Hospitalo-Universitaire Fighting Prematurity, 75005, Paris, France
| | - Arnaud Firon
- Department of Microbiology, Biology of Gram-positive Pathogens, Institut Pasteur, Université Paris Cité, 75015, Paris, France
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Siletti C, Freeman M, Tu Z, Stevenson DM, Amador-Noguez D, Sauer JD, Huynh TN. C-di-AMP accumulation disrupts glutathione metabolism and inhibits virulence program expression in Listeria monocytogenes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.18.576247. [PMID: 38293011 PMCID: PMC10827153 DOI: 10.1101/2024.01.18.576247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
C-di-AMP is an essential second messenger in many bacteria but its levels must be regulated. Unregulated c-di-AMP accumulation attenuates the virulence of many bacterial pathogens, including those that do not require c-di-AMP for growth. However, the mechanisms by which c-di-AMP regulates bacterial pathogenesis remain poorly understood. In Listeria monocytogenes , a mutant lacking both c-di-AMP phosphodiesterases, denoted as the ΔPDE mutant, accumulates a high c-di-AMP level and is significantly attenuated in the mouse model of systemic infection. All key L. monocytogenes virulence genes are transcriptionally upregulated by the master transcription factor PrfA, which is activated by reduced glutathione (GSH) during infection. Our transcriptomic analysis revealed that the ΔPDE mutant is significantly impaired for the expression of virulence genes within the PrfA core regulon. Subsequent quantitative gene expression analyses validated this phenotype both at the basal level and upon PrfA activation by GSH. A constitutively active PrfA * variant, PrfA G145S, which mimics the GSH-bound conformation, restores virulence gene expression in ΔPDE but only partially rescues virulence defect. Through GSH quantification and uptake assays, we found that the ΔPDE strain is significantly depleted for GSH, and that c-di-AMP inhibits GSH uptake. Constitutive expression of gshF (encoding a GSH synthetase) does not restore GSH levels in the ΔPDE strain, suggesting that c-di-AMP inhibits GSH synthesis activity or promotes GSH catabolism. Taken together, our data reveals GSH metabolism as another pathway that is regulated by c-di-AMP. C-di-AMP accumulation depletes cytoplasmic GSH levels within L. monocytogenes that leads to impaired virulence program expression. IMPORTANCE C-di-AMP regulates both bacterial pathogenesis and interactions with the host. Although c-di-AMP is essential in many bacteria, its accumulation also attenuates the virulence of many bacterial pathogens. Therefore, disrupting c-di-AMP homeostasis is a promising antibacterial treatment strategy, and has inspired several studies that screened for chemical inhibitors of c-di-AMP phosphodiesterases. However, the mechanisms by which c-di-AMP accumulation diminishes bacterial pathogenesis are poorly understood. Such understanding will reveal the molecular function of c-di-AMP, and inform therapeutic development strategies. Here, we identify GSH metabolism as a pathway regulated by c-di-AMP that is pertinent to L. monocytogenes replication in the host. Given the role of GSH as a virulence signal, nutrient, and antioxidant, GSH depletion impairs virulence program expression and likely diminishes host adaptation.
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7
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Meireles D, Pombinho R, Cabanes D. Signals behind Listeria monocytogenes virulence mechanisms. Gut Microbes 2024; 16:2369564. [PMID: 38979800 PMCID: PMC11236296 DOI: 10.1080/19490976.2024.2369564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 06/13/2024] [Indexed: 07/10/2024] Open
Abstract
The tight and coordinated regulation of virulence gene expression is crucial to ensure the survival and persistence of bacterial pathogens in different contexts within their hosts. Considering this, bacteria do not express virulence factors homogenously in time and space, either due to their associated fitness cost or to their detrimental effect at specific infection stages. To efficiently infect and persist into their hosts, bacteria have thus to monitor environmental cues or chemical cell-to-cell signaling mechanisms that allow their transition from the external environment to the host, and therefore adjust gene expression levels, intrinsic biological activities, and appropriate behaviors. Listeria monocytogenes (Lm), a major Gram-positive facultative intracellular pathogen, stands out for its adaptability and capacity to thrive in a wide range of environments. Because of that, Lm presents itself as a significant concern in food safety and public health, that can lead to potentially life-threatening infections in humans. A deeper understanding of the intricate bacterial virulence mechanisms and the signals that control them provide valuable insights into the dynamic interplay between Lm and the host. Therefore, this review addresses the role of some crucial signals behind Lm pathogenic virulence mechanisms and explores how the ability to assimilate and interpret these signals is fundamental for pathogenesis, identifying potential targets for innovative antimicrobial strategies.
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Affiliation(s)
- Diana Meireles
- Instituto de Investigação e Inovação em Saúde, Porto, Portugal
- Group of Molecular Microbiology, IBMC, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar – ICBAS, Porto, Portugal
| | - Rita Pombinho
- Instituto de Investigação e Inovação em Saúde, Porto, Portugal
- Group of Molecular Microbiology, IBMC, Porto, Portugal
| | - Didier Cabanes
- Instituto de Investigação e Inovação em Saúde, Porto, Portugal
- Group of Molecular Microbiology, IBMC, Porto, Portugal
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8
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Wright MJ, Bai G. Bacterial second messenger cyclic di-AMP in streptococci. Mol Microbiol 2023; 120:791-804. [PMID: 37898560 DOI: 10.1111/mmi.15187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/10/2023] [Accepted: 10/15/2023] [Indexed: 10/30/2023]
Abstract
Cyclic dimeric adenosine monophosphate (c-di-AMP) has been well studied in bacteria, including those of the genus Streptococcus, since the first recognition of this dinucleotide in 2008. Streptococci possess a sole diadenylate cyclase, CdaA, and distinct c-di-AMP phosphodiesterases. Interestingly, cdaA is required for viability of some streptococcal species but not all when streptococci are grown in standard laboratory media. Bacteria of this genus also have distinct c-di-AMP effector proteins, diverse c-di-AMP-signaling pathways, and subsequent biological outcomes. In streptococci, c-di-AMP may influence bacterial growth, morphology, biofilm formation, competence program, drug resistance, and bacterial pathogenesis. c-di-AMP secreted by streptococci has also been shown to interact with the mammalian host and induces immune responses including type I interferon production. In this review, we summarize the reported c-di-AMP networks in seven species of the genus Streptococcus, which cause diverse clinical manifestations, and propose future perspectives to investigate the signaling molecule in these streptococcal pathogens.
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Affiliation(s)
- Michael J Wright
- Department of Internal Medicine, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Guangchun Bai
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, New York, USA
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9
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Fung DK, Trinquier AE, Wang JD. Crosstalk between (p)ppGpp and other nucleotide second messengers. Curr Opin Microbiol 2023; 76:102398. [PMID: 37866203 PMCID: PMC10842992 DOI: 10.1016/j.mib.2023.102398] [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: 08/07/2023] [Revised: 09/25/2023] [Accepted: 09/27/2023] [Indexed: 10/24/2023]
Abstract
In response to environmental cues, bacteria produce intracellular nucleotide messengers to regulate a wide variety of cellular processes and physiology. Studies on individual nucleotide messengers, such as (p)ppGpp or cyclic (di)nucleotides, have established their respective regulatory themes. As research on nucleotide signaling networks expands, recent studies have begun to uncover various crosstalk mechanisms between (p)ppGpp and other nucleotide messengers, including signal conversion, allosteric regulation, and target competition. The multiple layers of crosstalk implicate that (p)ppGpp is intricately linked to different nucleotide signaling pathways. From a physiological perspective, (p)ppGpp crosstalk enables fine-tuning and feedback regulation with other nucleotide messengers to achieve optimal adaptation.
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Affiliation(s)
- Danny K Fung
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Aude E Trinquier
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jue D Wang
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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10
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Zhu X, Baranowski E, Hao Z, Li X, Zhao G, Dong Y, Chen Y, Hu C, Chen H, Citti C, Wang A, Guo A. An atypical GdpP enzyme linking cyclic nucleotide metabolism to osmotic tolerance and gene regulation in Mycoplasma bovis. Front Microbiol 2023; 14:1250368. [PMID: 38098652 PMCID: PMC10720645 DOI: 10.3389/fmicb.2023.1250368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 11/10/2023] [Indexed: 12/17/2023] Open
Abstract
Nucleotide second messengers play an important role in bacterial adaptation to environmental changes. Recent evidence suggests that some of these regulatory molecular pathways were conserved upon the degenerative evolution of the wall-less mycoplasmas. We have recently reported the occurrence of a phosphodiesterase (PDE) in the ruminant pathogen Mycoplasma bovis, which was involved in c-di-AMP metabolism. In the present study, we demonstrate that the genome of this mycoplasma species encodes a PDE of the GdpP family with atypical DHH domains. Characterization of M. bovis GdpP (MbovGdpP) revealed a multifunctional PDE with unusual nanoRNase and single-stranded DNase activities. The alarmone ppGpp was found unable to inhibit c-di-NMP degradation by MbovGdpP but efficiently blocked its nanoRNase activity. Remarkably, MbovGdpP was found critical for the osmotic tolerance of M. bovis under K+ and Na+ conditions. Transcriptomic analyses further revealed the biological importance of MbovGdpP in tRNA biosynthesis, pyruvate metabolism, and several steps in genetic information processing. This study is an important step in understanding the role of PDE and nucleotide second messengers in the biology of a minimal bacterial pathogen.
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Affiliation(s)
- Xifang Zhu
- School of Life Sciences, Zhengzhou University, Zhengzhou, China
- Longhu Laboratory of Advanced Immunology, Zhengzhou, China
- The State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | | | - Zhiyu Hao
- The State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Xixi Li
- The State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Gang Zhao
- The State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Yaqi Dong
- The State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Yingyu Chen
- The State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Changmin Hu
- The State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- The State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People’s Republic of China, Wuhan, China
- Hubei International Scientific and Technological Cooperation Base of Veterinary Epidemiology, International Research Center for Animal Disease, Ministry of Science and Technology of the People’s Republic of China, Wuhan, China
| | | | - Aiping Wang
- School of Life Sciences, Zhengzhou University, Zhengzhou, China
- Longhu Laboratory of Advanced Immunology, Zhengzhou, China
| | - Aizhen Guo
- The State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People’s Republic of China, Wuhan, China
- Hubei International Scientific and Technological Cooperation Base of Veterinary Epidemiology, International Research Center for Animal Disease, Ministry of Science and Technology of the People’s Republic of China, Wuhan, China
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Herzberg C, Meißner J, Warneke R, Stülke J. The many roles of cyclic di-AMP to control the physiology of Bacillus subtilis. MICROLIFE 2023; 4:uqad043. [PMID: 37954098 PMCID: PMC10636490 DOI: 10.1093/femsml/uqad043] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/21/2023] [Accepted: 10/19/2023] [Indexed: 11/14/2023]
Abstract
The dinucleotide cyclic di-AMP (c-di-AMP) is synthesized as a second messenger in the Gram-positive model bacterium Bacillus subtilis as well as in many bacteria and archaea. Bacillus subtilis possesses three diadenylate cyclases and two phosphodiesterases that synthesize and degrade the molecule, respectively. Among the second messengers, c-di-AMP is unique since it is essential for B. subtilis on the one hand but toxic upon accumulation on the other. This role as an "essential poison" is related to the function of c-di-AMP in the control of potassium homeostasis. C-di-AMP inhibits the expression and activity of potassium uptake systems by binding to riboswitches and transporters and activates the activity of potassium exporters. In this way, c-di-AMP allows the adjustment of uptake and export systems to achieve a balanced intracellular potassium concentration. C-di-AMP also binds to two dedicated signal transduction proteins, DarA and DarB. Both proteins seem to interact with other proteins in their apo state, i.e. in the absence of c-di-AMP. For DarB, the (p)ppGpp synthetase/hydrolase Rel and the pyruvate carboxylase PycA have been identified as targets. The interactions trigger the synthesis of the alarmone (p)ppGpp and of the acceptor molecule for the citric acid cycle, oxaloacetate, respectively. In the absence of c-di-AMP, many amino acids inhibit the growth of B. subtilis. This feature can be used to identify novel players in amino acid homeostasis. In this review, we discuss the different functions of c-di-AMP and their physiological relevance.
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Affiliation(s)
- Christina Herzberg
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Janek Meißner
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Robert Warneke
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany
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12
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Hengge R, Pruteanu M, Stülke J, Tschowri N, Turgay K. Recent advances and perspectives in nucleotide second messenger signaling in bacteria. MICROLIFE 2023; 4:uqad015. [PMID: 37223732 PMCID: PMC10118264 DOI: 10.1093/femsml/uqad015] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/28/2023] [Accepted: 04/13/2023] [Indexed: 05/25/2023]
Abstract
Nucleotide second messengers act as intracellular 'secondary' signals that represent environmental or cellular cues, i.e. the 'primary' signals. As such, they are linking sensory input with regulatory output in all living cells. The amazing physiological versatility, the mechanistic diversity of second messenger synthesis, degradation, and action as well as the high level of integration of second messenger pathways and networks in prokaryotes has only recently become apparent. In these networks, specific second messengers play conserved general roles. Thus, (p)ppGpp coordinates growth and survival in response to nutrient availability and various stresses, while c-di-GMP is the nucleotide signaling molecule to orchestrate bacterial adhesion and multicellularity. c-di-AMP links osmotic balance and metabolism and that it does so even in Archaea may suggest a very early evolutionary origin of second messenger signaling. Many of the enzymes that make or break second messengers show complex sensory domain architectures, which allow multisignal integration. The multiplicity of c-di-GMP-related enzymes in many species has led to the discovery that bacterial cells are even able to use the same freely diffusible second messenger in local signaling pathways that can act in parallel without cross-talking. On the other hand, signaling pathways operating with different nucleotides can intersect in elaborate signaling networks. Apart from the small number of common signaling nucleotides that bacteria use for controlling their cellular "business," diverse nucleotides were recently found to play very specific roles in phage defense. Furthermore, these systems represent the phylogenetic ancestors of cyclic nucleotide-activated immune signaling in eukaryotes.
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Affiliation(s)
- Regine Hengge
- Corresponding author. Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Philippstr. 13 – Haus 22, 10115 Berlin, Germany. Tel: +49-30-2093-49686; Fax: +49-30-2093-49682; E-mail:
| | | | - Jörg Stülke
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Natalia Tschowri
- Institute of Microbiology, Leibniz-Universität Hannover, 30419 Hannover, Germany
| | - Kürşad Turgay
- Institute of Microbiology, Leibniz-Universität Hannover, 30419 Hannover, Germany
- Max Planck Unit for the Science of Pathogens, 10115 Berlin, Germany
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13
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Ainelo A, Caballero-Montes J, Bulvas O, Ernits K, Coppieters ‘t Wallant K, Takada H, Craig SZ, Mazzucchelli G, Zedek S, Pichová I, Atkinson GC, Talavera A, Martens C, Hauryliuk V, Garcia-Pino A. The structure of DarB in complex with Rel NTD reveals nonribosomal activation of Rel stringent factors. SCIENCE ADVANCES 2023; 9:eade4077. [PMID: 36652515 PMCID: PMC9848473 DOI: 10.1126/sciadv.ade4077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Rel stringent factors are bifunctional ribosome-associated enzymes that catalyze both synthesis and hydrolysis of the alarmones (p)ppGpp. Besides the allosteric control by starved ribosomes and (p)ppGpp, Rel is regulated by various protein factors depending on specific stress conditions, including the c-di-AMP-binding protein DarB. However, how these effector proteins control Rel remains unknown. We have determined the crystal structure of the DarB2:RelNTD2 complex, uncovering that DarB directly engages the SYNTH domain of Rel to stimulate (p)ppGpp synthesis. This association with DarB promotes a SYNTH-primed conformation of the N-terminal domain region, markedly increasing the affinity of Rel for ATP while switching off the hydrolase activity of the enzyme. Binding to c-di-AMP rigidifies DarB, imposing an entropic penalty that precludes DarB-mediated control of Rel during normal growth. Our experiments provide the basis for understanding a previously unknown mechanism of allosteric regulation of Rel stringent factors independent of amino acid starvation.
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Affiliation(s)
- Andres Ainelo
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles 10 (ULB), Boulevard du Triomphe, Building BC (1C4 203), 1050 Brussels, Belgium
| | - Julien Caballero-Montes
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles 10 (ULB), Boulevard du Triomphe, Building BC (1C4 203), 1050 Brussels, Belgium
| | - Ondřej Bulvas
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nam. 2, 166 10 Prague 6, Czech Republic
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Karin Ernits
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Kyo Coppieters ‘t Wallant
- Centre for Structural Biology and Bioinformatics, Universite Libre de Bruxelles (ULB), Boulevard du Triomphe, Building BC, 1050 Bruxelles, Belgium
| | - Hiraku Takada
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo Motoyama, Kita-ku, Kyoto 603-8555, Japan
| | - Sophie Z. Craig
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles 10 (ULB), Boulevard du Triomphe, Building BC (1C4 203), 1050 Brussels, Belgium
| | - Gabriel Mazzucchelli
- Mass Spectrometry Laboratory, MolSys Research Unit, Liège Université, B-4000 Liège, Belgium
| | - Safia Zedek
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles 10 (ULB), Boulevard du Triomphe, Building BC (1C4 203), 1050 Brussels, Belgium
| | - Iva Pichová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo nam. 2, 166 10 Prague 6, Czech Republic
| | - Gemma C. Atkinson
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Ariel Talavera
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles 10 (ULB), Boulevard du Triomphe, Building BC (1C4 203), 1050 Brussels, Belgium
| | - Chloe Martens
- Centre for Structural Biology and Bioinformatics, Universite Libre de Bruxelles (ULB), Boulevard du Triomphe, Building BC, 1050 Bruxelles, Belgium
| | - Vasili Hauryliuk
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
- University of Tartu, Institute of Technology, 50411 Tartu, Estonia
| | - Abel Garcia-Pino
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles 10 (ULB), Boulevard du Triomphe, Building BC (1C4 203), 1050 Brussels, Belgium
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium
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14
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Covaleda-Cortés G, Mechaly A, Brissac T, Baehre H, Devaux L, England P, Raynal B, Hoos S, Gominet M, Firon A, Trieu-Cuot P, Kaminski PA. The c-di-AMP-binding protein CbpB modulates the level of ppGpp alarmone in Streptococcus agalactiae. FEBS J 2023. [PMID: 36629470 DOI: 10.1111/febs.16724] [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: 08/17/2022] [Revised: 12/07/2022] [Accepted: 01/09/2023] [Indexed: 01/12/2023]
Abstract
Cyclic di-AMP is an essential signalling molecule in Gram-positive bacteria. This second messenger regulates the osmotic pressure of the cell by interacting directly with the regulatory domains, either RCK_C or CBS domains, of several potassium and osmolyte uptake membrane protein systems. Cyclic di-AMP also targets stand-alone CBS domain proteins such as DarB in Bacillus subtilis and CbpB in Listeria monocytogenes. We show here that the CbpB protein of Group B Streptococcus binds c-di-AMP with a very high affinity. Crystal structures of CbpB reveal the determinants of binding specificity and significant conformational changes occurring upon c-di-AMP binding. Deletion of the cbpB gene alters bacterial growth in low potassium conditions most likely due to a decrease in the amount of ppGpp caused by a loss of interaction between CbpB and Rel, the GTP/GDP pyrophosphokinase.
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Affiliation(s)
- Giovanni Covaleda-Cortés
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR 6047, Institut Pasteur, Université Paris Cité, France
| | - Ariel Mechaly
- CNRS-UMR 3528, Crystallography Platform, Center for Technological Resources and Research, Institut Pasteur, Université Paris Cité, France
| | - Terry Brissac
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR 6047, Institut Pasteur, Université Paris Cité, France
| | - Heike Baehre
- Research Core Unit Metabolomics, Hannover Medical School, Germany
| | - Laura Devaux
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR 6047, Institut Pasteur, Université Paris Cité, France
| | - Patrick England
- CNRS UMR 3528, Molecular Biophysics Platform, Center for Technological Resources and Research, Institut Pasteur, Université Paris Cité, France
| | - Bertrand Raynal
- CNRS UMR 3528, Molecular Biophysics Platform, Center for Technological Resources and Research, Institut Pasteur, Université Paris Cité, France
| | - Sylviane Hoos
- CNRS UMR 3528, Molecular Biophysics Platform, Center for Technological Resources and Research, Institut Pasteur, Université Paris Cité, France
| | - Myriam Gominet
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR 6047, Institut Pasteur, Université Paris Cité, France
| | - Arnaud Firon
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR 6047, Institut Pasteur, Université Paris Cité, France
| | - Patrick Trieu-Cuot
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR 6047, Institut Pasteur, Université Paris Cité, France
| | - Pierre Alexandre Kaminski
- Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS UMR 6047, Institut Pasteur, Université Paris Cité, France
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15
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Cheung MY, Li X, Ku YS, Chen Z, Lam HM. Co-crystalization reveals the interaction between AtYchF1 and ppGpp. Front Mol Biosci 2022; 9:1061350. [PMID: 36533075 PMCID: PMC9748339 DOI: 10.3389/fmolb.2022.1061350] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 11/07/2022] [Indexed: 08/18/2023] Open
Abstract
AtYchF1 is an unconventional G-protein in Arabidopsis thaliana that exhibits relaxed nucleotide-binding specificity. The bindings between AtYchF1 and biomolecules including GTP, ATP, and 26S rRNA have been reported. In this study, we demonstrated the binding of AtYchF1 to ppGpp in addition to the above molecules. AtYchF1 is a cytosolic protein previously reported as a negative regulator of both biotic and abiotic stresses while the accumulation of ppGpp in the cytoplasm induces retarded plant growth and development. By co-crystallization, in vitro pull-down experiments, and hydrolytic biochemical assays, we demonstrated the binding and hydrolysis of ppGpp by AtYchF1. ppGpp inhibits the binding of AtYchF1 to ATP, GTP, and 26S rRNA. The ppGpp hydrolyzing activity of AtYchF1 failed to be activated by AtGAP1. The AtYchF1-ppGpp co-crystal structure suggests that ppGpp might prevent His136 from executing nucleotide hydrolysis. In addition, upon the binding of ppGpp, the conformation between the TGS and helical domains of AtYchF1 changes. Such structural changes probably influence the binding between AtYchF1 and other molecules such as 26S rRNA. Since YchF proteins are conserved among different kingdoms of life, the findings advance the knowledge on the role of AtYchF1 in regulating nucleotide signaling as well as hint at the possible involvement of YchF proteins in regulating ppGpp level in other species.
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Affiliation(s)
- Ming-Yan Cheung
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Xiaorong Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Yee-Shan Ku
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Hon-Ming Lam
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
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16
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Heidemann JL, Neumann P, Krüger L, Wicke D, Vinhoven L, Linden A, Dickmanns A, Stülke J, Urlaub H, Ficner R. Structural basis for c-di-AMP-dependent regulation of the bacterial stringent response by receptor protein DarB. J Biol Chem 2022; 298:102144. [PMID: 35714772 PMCID: PMC9293649 DOI: 10.1016/j.jbc.2022.102144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/09/2022] [Accepted: 06/11/2022] [Indexed: 10/31/2022] Open
Abstract
The bacterial second messenger c-di-AMP controls essential cellular processes, including potassium and osmolyte homeostasis. This makes synthesizing enzymes and components involved in c-di-AMP signal transduction intriguing as potential targets for drug development. The c-di-AMP receptor protein DarB of Bacillus subtilis is known to bind the Rel protein and trigger the Rel-dependent stringent response to stress conditions; however, the structural basis for this trigger is unclear. Here we report crystal structures of DarB in the ligand-free state and of DarB complexed with c-di-AMP, 3´3´-cGAMP, and AMP. We show that DarB forms a homodimer with a parallel, head-to-head assembly of the monomers. We also confirm the DarB dimer binds two cyclic di-nucleotide molecules or two AMP molecules; only one adenine of bound c-di-AMP is specifically recognized by DarB, while the second protrudes out of the donut-shaped protein. This enables DarB to bind also 3´3´-cGAMP, as only the adenine fits in the active site. In absence of c-di-AMP, we show DarB binds to Rel and stimulates (p)ppGpp synthesis, whereas the presence of c-di-AMP abolishes this interaction. Furthermore, the DarB crystal structures reveal no conformational changes upon c-di-AMP binding, leading us to conclude the regulatory function of DarB on Rel must be controlled directly by the bound c-di-AMP. We thus derived a structural model of the DarB-Rel complex via in silico docking, which was validated with mass spectrometric analysis of the chemically cross-linked DarB-Rel complex and mutagenesis studies. We suggest, based on the predicted complex structure, a mechanism of stringent response regulation by c-di-AMP.
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Affiliation(s)
| | | | - Larissa Krüger
- Department of General Microbiology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Dennis Wicke
- Department of General Microbiology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | | | - Andreas Linden
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | | | - Jörg Stülke
- Department of General Microbiology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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17
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Wang M, Wamp S, Gibhardt J, Holland G, Schwedt I, Schmidtke KU, Scheibner K, Halbedel S, Commichau FM. Adaptation of Listeria monocytogenes to perturbation of c-di-AMP metabolism underpins its role in osmoadaptation and identifies a fosfomycin uptake system. Environ Microbiol 2022; 24:4466-4488. [PMID: 35688634 DOI: 10.1111/1462-2920.16084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/25/2022] [Indexed: 11/29/2022]
Abstract
The human pathogen Listeria monocytogenes synthesizes and degrades c-di-AMP using the diadenylate cyclase CdaA and the phosphodiesterases PdeA and PgpH respectively. c-di-AMP is essential because it prevents the uncontrolled uptake of osmolytes. Here, we studied the phenotypes of cdaA, pdeA, pgpH and pdeA pgpH mutants with defects in c-di-AMP metabolism and characterized suppressor mutants restoring their growth defects. The characterization of the pdeA pgpH mutant revealed that the bacteria show growth defects in defined medium, a phenotype that is invariably suppressed by mutations in cdaA. The previously reported growth defect of the cdaA mutant in rich medium is suppressed by mutations that osmotically stabilize the c-di-AMP-free strain. We also found that the cdaA mutant has an increased sensitivity against isoleucine. The isoleucine-dependent growth inhibition of the cdaA mutant is suppressed by codY mutations that likely reduce the DNA-binding activity of encoded CodY variants. Moreover, the characterization of the cdaA suppressor mutants revealed that the Opp oligopeptide transport system is involved in the uptake of the antibiotic fosfomycin. In conclusion, the suppressor analysis corroborates a key function of c-di-AMP in controlling osmolyte homeostasis in L. monocytogenes.
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Affiliation(s)
- Mengyi Wang
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany.,Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany.,FG Molecular Microbiology, Institute of Biology, University of Hohenheim, 70599, Stuttgart, Germany
| | - Sabrina Wamp
- Division of Enteropathogenic Bacteria and Legionella, Robert-Koch-Institute, 38855, Wernigerode, Germany
| | - Johannes Gibhardt
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany.,Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany.,Research Complex NanoBio, Peter the Great Saint Petersburg Polytechnic University, Politekhnicheskaya ulitsa 29A, Saint Petersburg, 195251, Russia
| | - Gudrun Holland
- ZBS4 - Advanced Light and Electron Microscopy, Robert-Koch-Institute, Seestraße 10, 13353, Berlin, Germany
| | - Inge Schwedt
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany.,FG Molecular Microbiology, Institute of Biology, University of Hohenheim, 70599, Stuttgart, Germany
| | - Kai-Uwe Schmidtke
- FG Enzyme Technology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany
| | - Katrin Scheibner
- FG Enzyme Technology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany
| | - Sven Halbedel
- Division of Enteropathogenic Bacteria and Legionella, Robert-Koch-Institute, 38855, Wernigerode, Germany
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany.,FG Molecular Microbiology, Institute of Biology, University of Hohenheim, 70599, Stuttgart, Germany
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18
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Abram F, Arcari T, Guerreiro D, O'Byrne CP. Evolutionary trade-offs between growth and survival: The delicate balance between reproductive success and longevity in bacteria. Adv Microb Physiol 2021; 79:133-162. [PMID: 34836610 DOI: 10.1016/bs.ampbs.2021.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
All living cells strive to allocate cellular resources in a way that promotes maximal evolutionary fitness. While there are many competing demands for resources the main decision making process centres on whether to proceed with growth and reproduction or to "hunker down" and invest in protection and survival (or to strike an optimal balance between these two processes). The transcriptional programme active at any given time largely determines which of these competing processes is dominant. At the top of the regulatory hierarchy are the sigma factors that commandeer the transcriptional machinery and determine which set of promoters are active at any given time. The regulatory inputs controlling their activity are therefore often highly complex, with multiple layers of regulation, allowing relevant environmental information to produce the most beneficial response. The tension between growth and survival is also evident in the developmental programme necessary to promote biofilm formation, which is typically associated with low growth rates and enhanced long-term survival. Nucleotide second messengers and energy pools (ATP/ADP levels) play critical roles in determining the fate of individual cells. Regulatory small RNAs frequently play important roles in the decision making processes too. In this review we discuss the trade-off that exists between reproduction and persistence in bacteria and discuss some of the recent advances in this fascinating field.
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Affiliation(s)
- Florence Abram
- Microbiology & Ryan Institute, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Talia Arcari
- Microbiology & Ryan Institute, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Duarte Guerreiro
- Microbiology & Ryan Institute, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Conor P O'Byrne
- Microbiology & Ryan Institute, School of Natural Sciences, National University of Ireland, Galway, Ireland.
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19
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Anderson BW, Fung DK, Wang JD. Regulatory Themes and Variations by the Stress-Signaling Nucleotide Alarmones (p)ppGpp in Bacteria. Annu Rev Genet 2021; 55:115-133. [PMID: 34416118 DOI: 10.1146/annurev-genet-021821-025827] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bacterial stress-signaling alarmones are important components of a protective network against diverse stresses such as nutrient starvation and antibiotic assault. pppGpp and ppGpp, collectively (p)ppGpp, have well-documented regulatory roles in gene expression and protein translation. Recent work has highlighted another key function of (p)ppGpp: inducing rapid and coordinated changes in cellular metabolism by regulating enzymatic activities, especially those involved in purine nucleotide synthesis. Failure of metabolic regulation by (p)ppGpp results in the loss of coordination between metabolic and macromolecular processes, leading to cellular toxicity. In this review, we document how (p)ppGpp and newly characterized nucleotides pGpp and (p)ppApp directly regulate these enzymatic targets for metabolic remodeling. We examine targets' common determinants for alarmone interaction as well as their evolutionary diversification. We highlight classical and emerging themes in nucleotide signaling, including oligomerization and allostery along with metabolic interconversion and crosstalk, illustrating how they allow optimized bacterial adaptation to their environmental niches.
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Affiliation(s)
- Brent W Anderson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; , ,
| | - Danny K Fung
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; , ,
| | - Jue D Wang
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; , ,
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20
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Mudgal S, Manikandan K, Mukherjee A, Krishnan A, Sinha KM. Cyclic di-AMP: Small molecule with big roles in bacteria. Microb Pathog 2021; 161:105264. [PMID: 34715302 DOI: 10.1016/j.micpath.2021.105264] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/20/2021] [Accepted: 10/21/2021] [Indexed: 01/15/2023]
Abstract
Cyclic dinucleotides are second messengers that are present in all the three domains of life, bacteria, archaea, and eukaryotes. These dinucleotides have important physiological and pathophysiological roles in bacteria. Cyclic di-AMP (cdA) is one of the recently discovered cyclic dinucleotides present predominantly in gram-positive bacteria. cdA is synthesized through diadenylate cyclase (DAC) activity from ATP in a two-step process and hydrolyzed to linear dinucleotide pApA (and to 5' AMP in certain cases) by specific phosphodiesterases. cdA regulates various physiological processes like K+ transport and osmotic balance, DNA repair, cell wall homeostasis, drug resistance, central metabolism either by binding directly to the target protein or regulating its expression. It also participates in host-pathogen interaction by binding to host immune receptors ERAdP, RECON, and STING.
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Affiliation(s)
- Sudhanshu Mudgal
- Amity Institute of Biotechnology, Amity University Haryana, Haryana, India
| | - Kasi Manikandan
- Amity Institute of Biotechnology, Amity University Haryana, Haryana, India
| | - Ahana Mukherjee
- Amity Institute of Biotechnology, Amity University Haryana, Haryana, India
| | - Anuja Krishnan
- Department of Molecular Medicine, Jamia Hamdard, New Delhi, India.
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Kundra S, Lam LN, Kajfasz JK, Casella LG, Andersen MJ, Abranches J, Flores-Mireles AL, Lemos JA. c-di-AMP Is Essential for the Virulence of Enterococcus faecalis. Infect Immun 2021; 89:e0036521. [PMID: 34424750 PMCID: PMC8519298 DOI: 10.1128/iai.00365-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/11/2021] [Indexed: 12/12/2022] Open
Abstract
Second messenger nucleotides are produced by bacteria in response to environmental stimuli and play a major role in the regulation of processes associated with bacterial fitness, including but not limited to osmoregulation, envelope homeostasis, central metabolism, and biofilm formation. In this study, we uncovered the biological significance of c-di-AMP in the opportunistic pathogen Enterococcus faecalis by isolating and characterizing strains lacking genes responsible for c-di-AMP synthesis (cdaA) and degradation (dhhP and gdpP). Using complementary approaches, we demonstrated that either complete loss of c-di-AMP (ΔcdaA strain) or c-di-AMP accumulation (ΔdhhP, ΔgdpP, and ΔdhhP ΔgdpP strains) drastically impaired general cell fitness and virulence of E. faecalis. In particular, the ΔcdaA strain was highly sensitive to envelope-targeting antibiotics, was unable to multiply and quickly lost viability in human serum or urine ex vivo, and was virtually avirulent in an invertebrate (Galleria mellonella) and in two catheter-associated mouse infection models that recapitulate key aspects of enterococcal infections in humans. In addition to evidence linking these phenotypes to altered activity of metabolite and peptide transporters and inability to maintain osmobalance, we found that the attenuated virulence of the ΔcdaA strain also could be attributed to a defect in Ebp pilus production and activity that severely impaired biofilm formation under both in vitro and in vivo conditions. Collectively, these results demonstrate that c-di-AMP signaling is essential for E. faecalis pathogenesis and a desirable target for drug development.
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Affiliation(s)
- Shivani Kundra
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Ling Ning Lam
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Jessica K. Kajfasz
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Leila G. Casella
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Marissa J. Andersen
- Department of Biological Sciences, University of Norte Dame, Notre Dame, Indiana, USA
| | - Jacqueline Abranches
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Ana L. Flores-Mireles
- Department of Biological Sciences, University of Norte Dame, Notre Dame, Indiana, USA
| | - José A. Lemos
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
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22
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Léger L, Byrne D, Guiraud P, Germain E, Maisonneuve E. NirD curtails the stringent response by inhibiting RelA activity in Escherichia coli. eLife 2021; 10:64092. [PMID: 34323689 PMCID: PMC8321558 DOI: 10.7554/elife.64092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 07/08/2021] [Indexed: 11/19/2022] Open
Abstract
Bacteria regulate their metabolism to adapt and survive adverse conditions, in particular to stressful downshifts in nutrient availability. These shifts trigger the so-called stringent response, coordinated by the signaling molecules guanosine tetra and pentaphosphate collectively referred to as (p)ppGpp. In Escherichia coli, accumulation of theses alarmones depends on the (p)ppGpp synthetase RelA and the bifunctional (p)ppGpp synthetase/hydrolase SpoT. A tight regulation of these intracellular activities is therefore crucial to rapidly adjust the (p)ppGpp levels in response to environmental stresses but also to avoid toxic consequences of (p)ppGpp over-accumulation. In this study, we show that the small protein NirD restrains RelA-dependent accumulation of (p)ppGpp and can inhibit the stringent response in E. coli. Mechanistically, our in vivo and in vitro studies reveal that NirD directly binds the catalytic domains of RelA to balance (p)ppGpp accumulation. Finally, we show that NirD can control RelA activity by directly inhibiting the rate of (p)ppGpp synthesis.
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Affiliation(s)
- Loïc Léger
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix Marseille Univ (UMR7283), Marseille, France
| | - Deborah Byrne
- Protein Expression Facility, Institut de Microbiologie de la Méditerranée, CNRS-Aix Marseille Univ, Marseille, France
| | - Paul Guiraud
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix Marseille Univ (UMR7283), Marseille, France
| | - Elsa Germain
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix Marseille Univ (UMR7283), Marseille, France
| | - Etienne Maisonneuve
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, CNRS-Aix Marseille Univ (UMR7283), Marseille, France
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23
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A rationally designed c-di-AMP FRET biosensor to monitor nucleotide dynamics. J Bacteriol 2021; 203:e0008021. [PMID: 34309402 DOI: 10.1128/jb.00080-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
3'3'-cyclic di-adenosine monophosphate (c-di-AMP) is an important nucleotide second messenger found throughout the bacterial domain of life. C-di-AMP is essential in many bacteria and regulates a diverse array of effector proteins controlling pathogenesis, cell wall homeostasis, osmoregulation, and central metabolism. Despite the ubiquity and importance of c-di-AMP, methods to detect this signaling molecule are limited, particularly at single cell resolution. In this work, crystallization of the Listeria monocytogenes c-di-AMP effector protein Lmo0553 enabled structure guided design of a Förster resonance energy transfer (FRET) based biosensor, which we have named CDA5. CDA5 is a fully genetically encodable, specific, and reversible biosensor which allows for the detection of c-di-AMP dynamics both in vitro and within live cells in a nondestructive manner. Our initial studies identify a distribution of c-di-AMP in Bacillus subtilis populations first grown in Luria Broth and then resuspended in diluted Luria Broth compatible with florescence analysis. Furthermore, we find that B. subtilis mutants lacking either a c-di-AMP phosphodiesterase or cyclase have respectively higher and lower FRET responses. These findings provide novel insight into the c-di-AMP distribution within bacterial populations and establish CDA5 as a powerful platform for characterizing new aspects of c-di-AMP regulation. Importance C-di-AMP is an important nucleotide second messenger for which detection methods are severely limited. In this work we engineer and implement a c-di-AMP specific FRET biosensor to remedy this dearth. We present this biosensor, CDA5, as a versatile tool to investigate previously intractable facets of c-di-AMP biology.
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24
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The Diadenylate Cyclase CdaA Is Critical for Borrelia turicatae Virulence and Physiology. Infect Immun 2021; 89:IAI.00787-20. [PMID: 33846120 PMCID: PMC8316131 DOI: 10.1128/iai.00787-20] [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] [Received: 12/16/2020] [Accepted: 03/22/2021] [Indexed: 12/16/2022] Open
Abstract
Relapsing fever (RF), caused by spirochetes of the genus Borrelia, is a globally distributed, vector-borne disease with high prevalence in developing countries. To date, signaling pathways required for infection and virulence of RF Borrelia spirochetes are unknown. Cyclic di-AMP (c-di-AMP), synthesized by diadenylate cyclases (DACs), is a second messenger predominantly found in Gram-positive organisms that is linked to virulence and essential physiological processes. Although Borrelia is Gram-negative, it encodes one DAC (CdaA), and its importance remains undefined. To investigate the contribution of c-di-AMP signaling in the RF bacterium Borrelia turicatae, a cdaA mutant was generated. The mutant was significantly attenuated during murine infection, and genetic complementation reversed this phenotype. Because c-di-AMP is essential for viability in many bacteria, whole-genome sequencing was performed on cdaA mutants, and single-nucleotide polymorphisms identified potential suppressor mutations. Additionally, conditional mutation of cdaA confirmed that CdaA is important for normal growth and physiology. Interestingly, mutation of cdaA did not affect expression of homologs of virulence regulators whose levels are impacted by c-di-AMP signaling in the Lyme disease bacterium Borrelia burgdorferi Finally, the cdaA mutant had a significant growth defect when grown with salts, at decreased osmolarity, and without pyruvate. While the salt treatment phenotype was not reversed by genetic complementation, possibly due to suppressor mutations, growth defects at decreased osmolarity and in media lacking pyruvate could be attributed directly to cdaA inactivation. Overall, these results indicate CdaA is critical for B. turicatae pathogenesis and link c-di-AMP to osmoregulation and central metabolism in RF spirochetes.
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25
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Richts B, Lentes S, Poehlein A, Daniel R, Commichau FM. A Bacillus subtilis ΔpdxT mutant suppresses vitamin B6 limitation by acquiring mutations enhancing pdxS gene dosage and ammonium assimilation. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:218-233. [PMID: 33559288 DOI: 10.1111/1758-2229.12936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Pyridoxal-5'-phosphate (PLP), the biologically active form of vitamin B6, serves as a cofactor for many enzymes. The Gram-positive model bacterium Bacillus subtilis synthesizes PLP via the PdxST enzyme complex, consisting of the PdxT glutaminase and the PdxS PLP synthase subunits, respectively. PdxT converts glutamine to glutamate and ammonia of which the latter is channelled to PdxS. At high extracellular ammonium concentrations, the PdxS PLP synthase subunit does not depend on PdxT. Here, we assessed the potential of a B. subtilis ΔpdxT mutant to adapt to PLP limitation at the genome level. The majority of ΔpdxT suppressors had amplified a genomic region containing the pdxS gene. We also identified mutants having acquired as yet undescribed mutations in ammonium assimilation genes, indicating that the overproduction of PdxS and the NrgA ammonium transporter partially relieve vitamin B6 limitation in a ΔpdxT mutant when extracellular ammonium is scarce. Furthermore, we found that PdxS positively affects complex colony formation in B. subtilis. The catalytic mechanism of the PdxS PLP synthase subunit could be the reason for the limited evolution of the enzyme and why we could not identify a PdxS variant producing PLP independently of PdxT at low ammonium concentrations.
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Affiliation(s)
- Björn Richts
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, Göttingen, 37077, Germany
| | - Sabine Lentes
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, Göttingen, 37077, Germany
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology, Institute for Microbiology and Genetics, University of Goettingen, Göttingen, 37077, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology, Institute for Microbiology and Genetics, University of Goettingen, Göttingen, 37077, Germany
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Senftenberg, 01968, Germany
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26
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Sustained Control of Pyruvate Carboxylase by the Essential Second Messenger Cyclic di-AMP in Bacillus subtilis. mBio 2021; 13:e0360221. [PMID: 35130724 PMCID: PMC8822347 DOI: 10.1128/mbio.03602-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In Bacillus subtilis and other Gram-positive bacteria, cyclic di-AMP is an essential second messenger that signals potassium availability by binding to a variety of proteins. In some bacteria, c-di-AMP also binds to the pyruvate carboxylase to inhibit its activity. We have discovered that in B. subtilis the c-di-AMP target protein DarB, rather than c-di-AMP itself, specifically binds to pyruvate carboxylase both in vivo and in vitro. This interaction stimulates the activity of the enzyme, as demonstrated by in vitro enzyme assays and in vivo metabolite determinations. Both the interaction and the activation of enzyme activity require apo-DarB and are inhibited by c-di-AMP. Under conditions of potassium starvation and corresponding low c-di-AMP levels, the demand for citric acid cycle intermediates is increased. Apo-DarB helps to replenish the cycle by activating both pyruvate carboxylase gene expression and enzymatic activity via triggering the stringent response as a result of its interaction with the (p)ppGpp synthetase Rel and by direct interaction with the enzyme, respectively. IMPORTANCE If bacteria experience a starvation for potassium, by far the most abundant metal ion in every living cell, they have to activate high-affinity potassium transporters, switch off growth activities such as translation and transcription of many genes or replication, and redirect the metabolism in a way that the most essential functions of potassium can be taken over by metabolites. Importantly, potassium starvation triggers a need for glutamate-derived amino acids. In many bacteria, the responses to changing potassium availability are orchestrated by a nucleotide second messenger, cyclic di-AMP. c-di-AMP binds to factors involved directly in potassium homeostasis and to dedicated signal transduction proteins. Here, we demonstrate that in the Gram-positive model organism Bacillus subtilis, the c-di-AMP receptor protein DarB can bind to and, thus, activate pyruvate carboxylase, the enzyme responsible for replenishing the citric acid cycle. This interaction takes place under conditions of potassium starvation if DarB is present in the apo form and the cells are in need of glutamate. Thus, DarB links potassium availability to the control of central metabolism.
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27
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Krüger L, Herzberg C, Wicke D, Bähre H, Heidemann JL, Dickmanns A, Schmitt K, Ficner R, Stülke J. A meet-up of two second messengers: the c-di-AMP receptor DarB controls (p)ppGpp synthesis in Bacillus subtilis. Nat Commun 2021; 12:1210. [PMID: 33619274 PMCID: PMC7900238 DOI: 10.1038/s41467-021-21306-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 01/19/2021] [Indexed: 12/23/2022] Open
Abstract
Many bacteria use cyclic di-AMP as a second messenger to control potassium and osmotic homeostasis. In Bacillus subtilis, several c-di-AMP binding proteins and RNA molecules have been identified. Most of these targets play a role in controlling potassium uptake and export. In addition, c-di-AMP binds to two conserved target proteins of unknown function, DarA and DarB, that exclusively consist of the c-di-AMP binding domain. Here, we investigate the function of the c-di-AMP-binding protein DarB in B. subtilis, which consists of two cystathionine-beta synthase (CBS) domains. We use an unbiased search for DarB interaction partners and identify the (p)ppGpp synthetase/hydrolase Rel as a major interaction partner of DarB. (p)ppGpp is another second messenger that is formed upon amino acid starvation and under other stress conditions to stop translation and active metabolism. The interaction between DarB and Rel only takes place if the bacteria grow at very low potassium concentrations and intracellular levels of c-di-AMP are low. We show that c-di-AMP inhibits the binding of DarB to Rel and the DarB–Rel interaction results in the Rel-dependent accumulation of pppGpp. These results link potassium and c-di-AMP signaling to the stringent response and thus to the global control of cellular physiology. In several bacteria, cyclic di-AMP mediates potassium (K+) and osmotic homeostasis. Here, the authors show that DarB, a Bacillus subtilis protein previously reported to bind cyclic di-AMP, interacts with the (p)ppGpp synthetase/hydrolase Rel in a K+-dependent manner in turn leading to Rel-dependent accumulation of pppGpp under conditions of K+ starvation.
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Affiliation(s)
- Larissa Krüger
- Department of General Microbiology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Christina Herzberg
- Department of General Microbiology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Dennis Wicke
- Department of General Microbiology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Heike Bähre
- Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Jana L Heidemann
- Department of Molecular Structural Biology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Achim Dickmanns
- Department of Molecular Structural Biology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Kerstin Schmitt
- Department of Molecular Microbiology and Genetics, Service Unit LCMS Protein Analytics, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, Institute for Microbiology & Genetics, GZMB, Georg-August-University Göttingen, Göttingen, Germany.
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28
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Tran BM, Prabha H, Iyer A, O'Byrne C, Abee T, Poolman B. Measurement of Protein Mobility in Listeria monocytogenes Reveals a Unique Tolerance to Osmotic Stress and Temperature Dependence of Diffusion. Front Microbiol 2021; 12:640149. [PMID: 33679676 PMCID: PMC7925416 DOI: 10.3389/fmicb.2021.640149] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/21/2021] [Indexed: 11/18/2022] Open
Abstract
Protein mobility in the cytoplasm is essential for cellular functions, and slow diffusion may limit the rates of biochemical reactions in the living cell. Here, we determined the apparent lateral diffusion coefficient (DL) of GFP in Listeria monocytogenes as a function of osmotic stress, temperature, and media composition. We find that DL is much less affected by hyperosmotic stress in L. monocytogenes than under similar conditions in Lactococcus lactis and Escherichia coli. We find a temperature optimum for protein diffusion in L. monocytogenes at 30°C, which deviates from predicted trends from the generalized Stokes-Einstein equation under dilute conditions and suggests that the structure of the cytoplasm and macromolecular crowding vary as a function of temperature. The turgor pressure of L. monocytogenes is comparable to other Gram-positive bacteria like Bacillus subtilis and L. lactis but higher in a knockout strain lacking the stress-inducible sigma factor SigB. We discuss these findings in the context of how L. monocytogenes survives during environmental transmission and interaction with the human host.
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Affiliation(s)
- Buu Minh Tran
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
| | - Haritha Prabha
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
| | - Aditya Iyer
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
| | - Conor O'Byrne
- School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Tjakko Abee
- Laboratory of Food Microbiology, Wageningen University Research, Wageningen, Netherlands
| | - Bert Poolman
- Department of Biochemistry, University of Groningen, Groningen, Netherlands
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29
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Krüger L, Herzberg C, Rath H, Pedreira T, Ischebeck T, Poehlein A, Gundlach J, Daniel R, Völker U, Mäder U, Stülke J. Essentiality of c-di-AMP in Bacillus subtilis: Bypassing mutations converge in potassium and glutamate homeostasis. PLoS Genet 2021; 17:e1009092. [PMID: 33481774 PMCID: PMC7857571 DOI: 10.1371/journal.pgen.1009092] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 02/03/2021] [Accepted: 12/14/2020] [Indexed: 12/14/2022] Open
Abstract
In order to adjust to changing environmental conditions, bacteria use nucleotide second messengers to transduce external signals and translate them into a specific cellular response. Cyclic di-adenosine monophosphate (c-di-AMP) is the only known essential nucleotide second messenger. In addition to the well-established role of this second messenger in the control of potassium homeostasis, we observed that glutamate is as toxic as potassium for a c-di-AMP-free strain of the Gram-positive model bacterium Bacillus subtilis. In this work, we isolated suppressor mutants that allow growth of a c-di-AMP-free strain under these toxic conditions. Characterization of glutamate resistant suppressors revealed that they contain pairs of mutations, in most cases affecting glutamate and potassium homeostasis. Among these mutations, several independent mutations affected a novel glutamate transporter, AimA (Amino acid importer A, formerly YbeC). This protein is the major transporter for glutamate and serine in B. subtilis. Unexpectedly, some of the isolated suppressor mutants could suppress glutamate toxicity by a combination of mutations that affect phospholipid biosynthesis and a specific gain-of-function mutation of a mechanosensitive channel of small conductance (YfkC) resulting in the acquisition of a device for glutamate export. Cultivation of the c-di-AMP-free strain on complex medium was an even greater challenge because the amounts of potassium, glutamate, and other osmolytes are substantially higher than in minimal medium. Suppressor mutants viable on complex medium could only be isolated under anaerobic conditions if one of the two c-di-AMP receptor proteins, DarA or DarB, was absent. Also on complex medium, potassium and osmolyte toxicity are the major bottlenecks for the growth of B. subtilis in the absence of c-di-AMP. Our results indicate that the essentiality of c-di-AMP in B. subtilis is caused by the global impact of the second messenger nucleotide on different aspects of cellular physiology.
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Affiliation(s)
- Larissa Krüger
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Christina Herzberg
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Hermann Rath
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Tiago Pedreira
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Till Ischebeck
- Department of Plant Biochemistry, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Jan Gundlach
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Jörg Stülke
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
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30
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Fernández-Coll L, Cashel M. Possible Roles for Basal Levels of (p)ppGpp: Growth Efficiency Vs. Surviving Stress. Front Microbiol 2020; 11:592718. [PMID: 33162969 PMCID: PMC7581894 DOI: 10.3389/fmicb.2020.592718] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/16/2020] [Indexed: 11/18/2022] Open
Abstract
Two (p)ppGpp nucleotide analogs, sometimes abbreviated simply as ppGpp, are widespread in bacteria and plants. Their name alarmone reflects a view of their function as intracellular hormone-like protective alarms that can increase a 100-fold when sensing any of an array of physical or nutritional dangers, such as abrupt starvation, that trigger lifesaving adjustments of global gene expression and physiology. The diversity of mechanisms for stress-specific adjustments of this sort is large and further compounded by almost infinite microbial diversity. The central question raised by this review is whether the small basal levels of (p)ppGpp functioning during balanced growth serve very different roles than alarmone-like functions. Recent discoveries that abrupt amino acid starvation of Escherichia coli, accompanied by very high levels of ppGpp, occasion surprising instabilities of transfer RNA (tRNA), ribosomal RNA (rRNA), and ribosomes raises new questions. Is this destabilization, a mode of regulation linearly related to (p)ppGpp over the entire continuum of (p)ppGpp levels, including balanced growth? Are regulatory mechanisms exerted by basal (p)ppGpp levels fundamentally different than for high levels? There is evidence from studies of other organisms suggesting special regulatory features of basal levels compared to burst of (p)ppGpp. Those differences seem to be important even during bacterial infection, suggesting that unbalancing the basal levels of (p)ppGpp may become a future antibacterial treatment. A simile for this possible functional duality is that (p)ppGpp acts like a car’s brake, able to stop to avoid crashes as well as to slow down to drive safely.
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Affiliation(s)
- Llorenç Fernández-Coll
- Intramural Research Program, Eunice Kennedy Shriver NICHD, NIH, Bethesda, MD, United States
| | - Michael Cashel
- Intramural Research Program, Eunice Kennedy Shriver NICHD, NIH, Bethesda, MD, United States
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