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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:e0013024. [PMID: 38995039 DOI: 10.1128/jb.00130-24] [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: 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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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 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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3
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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 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
| | - Eduardo A Robleto
- School of Life Sciences, University of Nevada, Las Vegas, Nevada, USA
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4
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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:e0019024. [PMID: 38832794 DOI: 10.1128/jb.00190-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [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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5
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Zeden MS. mSphere of Influence: Targeting bacterial signaling and metabolism to overcome antimicrobial resistance. mSphere 2024; 9:e0063223. [PMID: 38305167 PMCID: PMC10900877 DOI: 10.1128/msphere.00632-23] [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] [Indexed: 02/03/2024] Open
Abstract
Dr Merve Suzan Zeden works in the field of molecular bacteriology and antibiotic resistance. In this mSphere of Influence article, she reflects on how three papers, entitled "c-di-AMP modulates Listeria monocytogenes central metabolism to regulate growth, antibiotic resistance and osmoregulation," "Amino acid catabolism in Staphylococcus aureus and the function of carbon catabolite repression," and "Evolving MRSA: high-level β-lactam resistance in Staphylococcus aureus is associated with RNA polymerase alterations and fine tuning of gene expression," made an impact on her work on bacterial metabolism and antimicrobial resistance and how it shaped her research in understanding the link in between.
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Affiliation(s)
- Merve S Zeden
- School of Biological and Chemical Sciences, College of Science and Engineering, University of Galway, Galway, Ireland
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6
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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] [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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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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8
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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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9
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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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10
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Feng Y, Chang SK, Portnoy DA. The major role of Listeria monocytogenes folic acid metabolism during infection is the generation of N-formylmethionine. mBio 2023; 14:e0107423. [PMID: 37695058 PMCID: PMC10653936 DOI: 10.1128/mbio.01074-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 09/12/2023] Open
Abstract
IMPORTANCE Folic acid is an essential vitamin for bacteria, plants, and animals. The lack of folic acid leads to various consequences such as a shortage of amino acids and nucleotides that are fundamental building blocks for life. Though antifolate drugs are widely used for antimicrobial treatments, the underlying mechanism of bacterial folate deficiency during infection is unclear. This study compares the requirements of different folic acid end-products during the infection of Listeria monocytogenes, a facultative intracellular pathogen of animals and humans. The results reveal the critical importance of N-formylmethionine, the amino acid used by bacteria to initiate protein synthesis. This work extends the current understanding of folic acid metabolism in pathogens and potentially provides new insights into antifolate drug development in the future.
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Affiliation(s)
- Ying Feng
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Shannon K. Chang
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
| | - Daniel A. Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
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11
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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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Berude JC, Kennouche P, Reniere ML, Portnoy DA. Listeria monocytogenes utilizes glutathione and limited inorganic sulfur compounds as a source of essential L-cysteine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562582. [PMID: 37905006 PMCID: PMC10614801 DOI: 10.1101/2023.10.16.562582] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Listeria monocytogenes ( Lm ) is a Gram-positive facultative intracellular pathogen that leads a biphasic lifecycle, transitioning its metabolism and selectively inducing virulence genes when it encounters mammalian hosts. Virulence gene expression is controlled by the master virulence regulator PrfA, which is allosterically activated by host- and bacterially-derived glutathione (GSH). The amino acid L-cysteine is the rate-limiting substrate for GSH synthesis in bacteria and is essential for bacterial growth. Unlike many bacteria, Lm is auxotrophic for L-cysteine and must import exogenous cysteine for growth and virulence. GSH is enriched in the host cytoplasm, and previous work suggests that Lm utilizes exogenous GSH for PrfA activation. Despite these observations, the import mechanism(s) for GSH remains elusive. Analysis of known GSH importers predicted a homologous importer in Lm comprised of the Ctp ABC transporter and the OppDF ATPases of the Opp oligopeptide importer. Here, we demonstrated that the Ctp complex is a high-affinity GSH/GSSG importer that is required for Lm growth at physiologically relevant concentrations. Further, we demonstrated that OppDF are required for GSH/GSSG import in an Opp-independent manner. These data support a model where Ctp and OppDF form a unique complex for GSH/GSSG import that supports growth and pathogenesis. Additionally, we show that Lm utilizes the inorganic sulfur sources thiosulfate and H 2 S for growth in a CysK-dependent manner in the absence of other L-cysteine sources. These findings suggest a pathoadaptive role for partial cysteine auxotrophy in Lm , where locally high GSH/GSSG or inorganic sulfur concentrations may signal arrival to distinct host niches.
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13
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Glover RC, Schwardt NH, Leano SKE, Sanchez ME, Thomason MK, Olive AJ, Reniere ML. A genome-wide screen in macrophages identifies PTEN as required for myeloid restriction of Listeria monocytogenes infection. PLoS Pathog 2023; 19:e1011058. [PMID: 37216395 PMCID: PMC10237667 DOI: 10.1371/journal.ppat.1011058] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 06/02/2023] [Accepted: 05/08/2023] [Indexed: 05/24/2023] Open
Abstract
Listeria monocytogenes (Lm) is an intracellular foodborne pathogen which causes the severe disease listeriosis in immunocompromised individuals. Macrophages play a dual role during Lm infection by both promoting dissemination of Lm from the gastrointestinal tract and limiting bacterial growth upon immune activation. Despite the relevance of macrophages to Lm infection, the mechanisms underlying phagocytosis of Lm by macrophages are not well understood. To identify host factors important for Lm infection of macrophages, we performed an unbiased CRISPR/Cas9 screen which revealed pathways that are specific to phagocytosis of Lm and those that are required for internalization of bacteria generally. Specifically, we discovered the tumor suppressor PTEN promotes macrophage phagocytosis of Lm and L. ivanovii, but not other Gram-positive bacteria. Additionally, we found that PTEN enhances phagocytosis of Lm via its lipid phosphatase activity by promoting adherence to macrophages. Using conditional knockout mice lacking Pten in myeloid cells, we show that PTEN-dependent phagocytosis is important for host protection during oral Lm infection. Overall, this study provides a comprehensive identification of macrophage factors involved in regulating Lm uptake and characterizes the function of one factor, PTEN, during Lm infection in vitro and in vivo. Importantly, these results demonstrate a role for opsonin-independent phagocytosis in Lm pathogenesis and suggest that macrophages play a primarily protective role during foodborne listeriosis.
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Affiliation(s)
- Rochelle C. Glover
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Nicole H. Schwardt
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Shania-Kate E. Leano
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Madison E. Sanchez
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Maureen K. Thomason
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Andrew J. Olive
- Department of Microbiology & Molecular Genetics, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, United States of America
| | - Michelle L. Reniere
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, United States of America
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14
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Gautam S, Mahapa A, Yeramala L, Gandhi A, Krishnan S, Kutti R. V, Chatterji D. Regulatory mechanisms of c-di-AMP synthase from Mycobacterium smegmatis revealed by a structure: Function analysis. Protein Sci 2023; 32:e4568. [PMID: 36660887 PMCID: PMC9926474 DOI: 10.1002/pro.4568] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/09/2023] [Accepted: 01/13/2023] [Indexed: 01/21/2023]
Abstract
Cyclic-di-nucleotide-based secondary messengers regulate various physiological functions, including stress responses in bacteria. Cyclic diadenosine monophosphate (c-di-AMP) has recently emerged as a crucial second messenger with implications in processes including osmoregulation, antibiotic resistance, biofilm formation, virulence, DNA repair, ion homeostasis, and sporulation, and has potential therapeutic applications. The contrasting activities of the enzymes diadenylate cyclase (DAC) and phosphodiesterase (PDE) determine the equilibrium levels of c-di-AMP. Although c-di-AMP is suspected of playing an essential role in the pathophysiology of bacterial infections and in regulating host-pathogen interactions, the mechanisms of its regulation remain relatively unexplored in mycobacteria. In this report, we biochemically and structurally characterize the c-di-AMP synthase (MsDisA) from Mycobacterium smegmatis. The enzyme activity is regulated by pH and substrate concentration; conditions of significance in the homoeostasis of c-di-AMP levels. Substrate binding stimulates conformational changes in the protein, and pApA and ppApA are synthetic intermediates detectable when enzyme efficiency is low. Unlike the orthologous Bacillus subtilis enzyme, MsDisA does not bind to, and its activity is not influenced in the presence of DNA. Furthermore, we have determined the cryo-EM structure of MsDisA, revealing asymmetry in its structure in contrast to the symmetric crystal structure of Thermotoga maritima DisA. We also demonstrate that the N-terminal minimal region alone is sufficient and essential for oligomerization and catalytic activity. Our data shed light on the regulation of mycobacterial DisA and possible future directions to pursue.
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Affiliation(s)
- Sudhanshu Gautam
- Molecular Biophysics UnitIndian Institute of ScienceBangaloreIndia
| | - Avisek Mahapa
- Molecular Biophysics UnitIndian Institute of ScienceBangaloreIndia
| | - Lahari Yeramala
- National Center for Biological SciencesTata Institute of Fundamental Research, GKVK PostBengaluruIndia
| | - Apoorv Gandhi
- Molecular Biophysics UnitIndian Institute of ScienceBangaloreIndia
| | - Sushma Krishnan
- Electron Microscopy Facility, Division of Biological SciencesIndian Institute of ScienceBangaloreIndia
| | - Vinothkumar Kutti R.
- National Center for Biological SciencesTata Institute of Fundamental Research, GKVK PostBengaluruIndia
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15
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C-di-AMP Is a Second Messenger in Corynebacterium glutamicum That Regulates Expression of a Cell Wall-Related Peptidase via a Riboswitch. Microorganisms 2023; 11:microorganisms11020296. [PMID: 36838266 PMCID: PMC9960051 DOI: 10.3390/microorganisms11020296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
Cyclic di-adenosine monophosphate (c-di-AMP) is a bacterial second messenger discovered in Bacillus subtilis and involved in potassium homeostasis, cell wall maintenance and/or DNA stress response. As the role of c-di-AMP has been mostly studied in Firmicutes, we sought to increase the understanding of its role in Actinobacteria, namely in Corynebacterium glutamicum. This organism is a well-known industrial production host and a model organism for pathogens, such as C. diphtheriae or Mycobacterium tuberculosis. Here, we identify and analyze the minimal set of two C. glutamicum enzymes, the diadenylate cyclase DisA and the phosphodiesterase PdeA, responsible for c-di-AMP metabolism. DisA synthesizes c-di-AMP from two molecules of ATP, whereas PdeA degrades c-di-AMP, as well as the linear degradation intermediate phosphoadenylyl-(3'→5')-adenosine (pApA) to two molecules of AMP. Here, we show that a ydaO/kimA-type c-di-AMP-dependent riboswitch controls the expression of the strictly regulated cell wall peptidase gene nlpC in C. glutamicum. In contrast to previously described members of the ydaO/kimA-type riboswitches, our results suggest that the C. glutamicum nlpC riboswitch likely affects the translation instead of the transcription of its downstream gene. Although strongly regulated by different mechanisms, we show that the absence of nlpC, the first known regulatory target of c-di-AMP in C. glutamicum, is not detrimental for this organism under the tested conditions.
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16
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para
-Aminobenzoic Acid Biosynthesis Is Required for Listeria monocytogenes Growth and Pathogenesis. Infect Immun 2022; 90:e0020722. [PMID: 36317877 PMCID: PMC9670987 DOI: 10.1128/iai.00207-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Biosyntheses of
para
-aminobenzoic acid (PABA) and its downstream folic acid metabolites are essential for one-carbon metabolism in all life forms and the targets of sulfonamide and trimethoprim antibiotics. In this study, we identified and characterized two genes (
pabA
and
pabBC
) required for PABA biosynthesis in
Listeria monocytogenes
.
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17
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Purcell EB. Rounding out cyclic dinucleotide signaling in Clostridioides difficile: A role and a mechanism for c-di-AMP. Sci Signal 2022; 15:eadd3937. [PMID: 36067335 DOI: 10.1126/scisignal.add3937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The second messenger c-di-AMP contributes to various homeostatic and stress responses in bacteria. In this issue of Science Signaling, Oberkampf et al. have identified it as a mediator of osmotic stress and bile salt resistance in the opportunistic pathogen Clostridioides difficile, with additional roles in cell wall homeostasis and biofilm formation.
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Affiliation(s)
- Erin B Purcell
- Department of Chemistry and Biochemistry, Old Dominion University, 4501 Elkhorn Avenue, Norfolk, VA 23529, USA.
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18
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Oberkampf M, Hamiot A, Altamirano-Silva P, Bellés-Sancho P, Tremblay YDN, DiBenedetto N, Seifert R, Soutourina O, Bry L, Dupuy B, Peltier J. c-di-AMP signaling is required for bile salt resistance, osmotolerance, and long-term host colonization by Clostridioides difficile. Sci Signal 2022; 15:eabn8171. [PMID: 36067333 PMCID: PMC9831359 DOI: 10.1126/scisignal.abn8171] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
To colonize the host and cause disease, the human enteropathogen Clostridioides difficile must sense, respond, and adapt to the harsh environment of the gastrointestinal tract. We showed that the production and degradation of cyclic diadenosine monophosphate (c-di-AMP) were necessary during different phases of C. difficile growth, environmental adaptation, and infection. The production of this nucleotide second messenger was essential for growth because it controlled the uptake of potassium and also contributed to biofilm formation and cell wall homeostasis, whereas its degradation was required for osmotolerance and resistance to detergents and bile salts. The c-di-AMP binding transcription factor BusR repressed the expression of genes encoding the compatible solute transporter BusAA-AB. Compared with the parental strain, a mutant lacking BusR was more resistant to hyperosmotic and bile salt stresses, whereas a mutant lacking BusAA was more susceptible. A short exposure of C. difficile cells to bile salts decreased intracellular c-di-AMP concentrations, suggesting that changes in membrane properties induce alterations in the intracellular c-di-AMP concentration. A C. difficile strain that could not degrade c-di-AMP failed to persist in a mouse gut colonization model as long as the wild-type strain did. Thus, the production and degradation of c-di-AMP in C. difficile have pleiotropic effects, including the control of osmolyte uptake to confer osmotolerance and bile salt resistance, and its degradation is important for host colonization.
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Affiliation(s)
- Marine Oberkampf
- Institut Pasteur, Université Paris Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015 Paris, France
| | - Audrey Hamiot
- Institut Pasteur, Université Paris Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015 Paris, France
| | - Pamela Altamirano-Silva
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Paula Bellés-Sancho
- Institut Pasteur, Université Paris Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015 Paris, France
| | - Yannick D. N. Tremblay
- Institut Pasteur, Université Paris Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015 Paris, France
| | - Nicholas DiBenedetto
- Massachusetts Host-Microbiome Center, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Roland Seifert
- Institute of Pharmacology and Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Olga Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Lynn Bry
- Massachusetts Host-Microbiome Center, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
- Clinical Microbiology Laboratory, Department of Pathology, Brigham and Women’s Hospital, Boston, MA, USA
| | - Bruno Dupuy
- Institut Pasteur, Université Paris Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015 Paris, France
| | - Johann Peltier
- Institut Pasteur, Université Paris Cité, UMR-CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, F-75015 Paris, France
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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19
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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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20
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RibU is an essential determinant of Listeria pathogenesis that mediates acquisition of FMN and FAD during intracellular growth. Proc Natl Acad Sci U S A 2022; 119:e2122173119. [PMID: 35316134 PMCID: PMC9060500 DOI: 10.1073/pnas.2122173119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Riboflavin (vitamin B2) is converted into flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are essential cofactors for many redox reactions across all domains of life. Listeria monocytogenes is a facultative intracellular pathogen that cannot synthesize riboflavin and must therefore obtain flavins from the host. In this study, we show that a previously identified riboflavin transporter (RibU) is essential for virulence and intracellular growth, but rather than transporting riboflavin, RibU transports FMN and FAD directly from the host cell cytosol. Mutants unable to convert riboflavin to FMN and FAD retained their capacity to grow intracellularly and were virulent, but they were unable to grow extracellularly and were thus converted from facultative to obligate intracellular pathogens. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are essential riboflavin-derived cofactors involved in a myriad of redox reactions across all forms of life. Nevertheless, the basis of flavin acquisition strategies by riboflavin auxotrophic pathogens remains poorly defined. In this study, we examined how the facultative intracellular pathogen Listeria monocytogenes, a riboflavin auxotroph, acquires flavins during infection. A L. monocytogenes mutant lacking the putative riboflavin transporter (RibU) was completely avirulent in mice but had no detectable growth defect in nutrient-rich media. However, unlike wild type, the RibU mutant was unable to grow in defined media supplemented with FMN or FAD or to replicate in macrophages starved for riboflavin. Consistent with RibU functioning to scavenge FMN and FAD inside host cells, a mutant unable to convert riboflavin to FMN or FAD retained virulence and grew in cultured macrophages and in spleens and livers of infected mice. However, this FMN- and FAD-requiring strain was unable to grow in the gallbladder or intestines, where L. monocytogenes normally grows extracellularly, suggesting that these sites do not contain sufficient flavin cofactors to promote replication. Thus, by deleting genes required to synthesize FMN and FAD, we converted L. monocytogenes from a facultative to an obligate intracellular pathogen. Collectively, these data indicate that L. monocytogenes requires riboflavin to grow extracellularly in vivo but scavenges FMN and FAD to grow in host cells.
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21
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Purcell EB. Second messenger signaling in Clostridioides difficile. Curr Opin Microbiol 2021; 65:138-144. [PMID: 34864551 DOI: 10.1016/j.mib.2021.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/18/2022]
Abstract
Small, diffusible second messenger molecules transmit information about extracellular conditions to intracellular machinery in order to influence transcription, translation, and metabolism. The enteropathogenic bacterium Clostridioides difficile coordinates its response to a dynamic and hostile environment via nucleotide second messengers. While riboswitch-mediated cyclic diguanylate regulation has been extensively characterized in C. difficile, signaling by cyclic diadenylate and by guanosine alarmones has only recently been confirmed in this organism. This review summarizes the current knowledge of how nucleotide second messenger signaling regulates physiological processes in C. difficile.
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Affiliation(s)
- Erin B Purcell
- Old Dominion University, Department of Chemistry and Biochemistry, 4501 Elkhorn Ave, Norfolk, VA 23529, United States.
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22
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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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23
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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: 4] [Impact Index Per Article: 1.3] [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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24
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NrnA is a linear dinucleotide phosphodiesterase with limited function in cyclic dinucleotide metabolism in Listeria monocytogenes. J Bacteriol 2021; 204:e0020621. [PMID: 34662239 DOI: 10.1128/jb.00206-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes produces both c-di-AMP and c-di-GMP to mediate many important cellular processes, but the levels of both nucleotides must be regulated. C-di-AMP accumulation attenuates virulence and diminishes stress response, and c-di-GMP accumulation impairs bacterial motility. An important regulatory mechanism to maintain c-di-AMP and c-di-GMP homeostasis is to hydrolyze them to the linear dinucleotides pApA and pGpG, respectively, but the fates of these hydrolytic products have not been examined in L. monocytogenes. We found that NrnA, a stand-alone DHH-DHHA1 phosphodiesterase, has a broad substrate range, but with a strong preference for linear dinucleotides over cyclic dinucleotides. Although NrnA exhibited detectable cyclic dinucleotide hydrolytic activities in vitro, NrnA had negligible effects on their levels in the bacterial cell, even in the absence of the c-di-AMP phosphodiesterases PdeA and PgpH. The ΔnrnA mutant had a mammalian cell infection defect that was fully restored by E. coli Orn. Together, our data indicate that L. monocytogenes NrnA is functionally orthologous to Orn, and its preferred physiological substrates are most likely linear dinucleotides. Furthermore, our findings revealed that, unlike some other c-di-AMP and c-di-GMP-producing bacteria, L. monocytogenes does not employ their hydrolytic products to regulate their phosphodiesterases, at least at the pApA and pGpG levels in the ΔnrnA mutant. Finally, the ΔnrnA infection defect was overcome by constitutive activation of PrfA, the master virulence regulator, suggesting that accumulated linear dinucleotides might inhibit the expression, stability, or function of PrfA-regulated virulence factors. IMPORTANCE Listeria monocytogenes produces both c-di-AMP and c-di-GMP, and encodes specific phosphodiesterases that degrade them into pApA and pGpG, respectively, but the metabolism of these products has not been characterized in this bacterium. We found that L. monocytogenes NrnA degrades a broad range of nucleotides. Among the tested cyclic and linear substrates, it exhibits a strong biochemical and physiological preference the linear dinucleotides pApA, pGpG, and pApG. Unlike in some other bacteria, these oligoribonucleotides do not appear to interfere with cyclic dinucleotide hydrolysis. The absence of NrnA is well tolerated by L. monocytogenes in broth cultures but impairs its ability to infect mammalian cells. These findings indicate a separation of cyclic dinucleotide signaling and oligoribonucleotide metabolism in L. monocytogenes.
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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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Anaya-Sanchez A, Feng Y, Berude JC, Portnoy DA. Detoxification of methylglyoxal by the glyoxalase system is required for glutathione availability and virulence activation in Listeria monocytogenes. PLoS Pathog 2021; 17:e1009819. [PMID: 34407151 PMCID: PMC8372916 DOI: 10.1371/journal.ppat.1009819] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/21/2021] [Indexed: 01/02/2023] Open
Abstract
Listeria monocytogenes is a Gram-positive, food-borne pathogen that lives a biphasic lifestyle, cycling between the environment and as a facultative intracellular pathogen of mammals. Upon entry into host cells, L. monocytogenes upregulates expression of glutathione synthase (GshF) and its product, glutathione (GSH), which is an allosteric activator of the master virulence regulator PrfA. Although gshF mutants are highly attenuated for virulence in mice and form very small plaques in host cell monolayers, these virulence defects can be fully rescued by mutations that lock PrfA in its active conformation, referred to as PrfA*. While PrfA activation can be recapitulated in vitro by the addition of reducing agents, the precise biological cue(s) experienced by L. monocytogenes that lead to PrfA activation are not known. Here we performed a genetic screen to identify additional small-plaque mutants that were rescued by PrfA* and identified gloA, which encodes glyoxalase A, a component of a GSH-dependent methylglyoxal (MG) detoxification system. MG is a toxic byproduct of metabolism produced by both the host and pathogen, which if accumulated, causes DNA damage and protein glycation. As a facultative intracellular pathogen, L. monocytogenes must protect itself from MG produced by its own metabolic processes and that of its host. We report that gloA mutants grow normally in broth, are sensitive to exogenous MG and severely attenuated upon IV infection in mice, but are fully rescued for virulence in a PrfA* background. We demonstrate that transcriptional activation of gshF increased upon MG challenge in vitro, and while this resulted in higher levels of GSH for wild-type L. monocytogenes, the glyoxalase mutants had decreased levels of GSH, presumably due to the accumulation of the GSH-MG hemithioacetal adduct. These data suggest that MG acts as a host cue that leads to GSH production and activation of PrfA.
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Affiliation(s)
- Andrea Anaya-Sanchez
- Graduate Group in Microbiology, University of California, Berkeley, Berkeley, California, United States of America
| | - Ying Feng
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - John C. Berude
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Daniel A. Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, United States of America
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Rørvik GH, Naemi A, Edvardsen PKT, Simm R. The c-di-AMP signaling system influences stress tolerance and biofilm formation of Streptococcus mitis. Microbiologyopen 2021; 10:e1203. [PMID: 34459556 PMCID: PMC8289670 DOI: 10.1002/mbo3.1203] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/07/2021] [Accepted: 05/14/2021] [Indexed: 11/16/2022] Open
Abstract
Streptococcus mitis is a commensal bacterial species of the oral cavity, with the potential for opportunistic pathogenesis. For successful colonization, S. mitis must be able to adhere to surfaces of the oral cavity and survive and adapt to frequently changing environmental conditions. Cyclic-di-AMP (c-di-AMP) is a nucleotide second messenger, involved in the regulation of stress responses and biofilm formation in several bacterial species. Cyclic-di-AMP is produced by diadenylate cyclases and degraded by phosphodiesterases. We have previously shown that in S. mitis, one diadenylate cyclase (CdaA) and at least two phosphodiesterases (Pde1 and Pde2) regulate the intracellular concentration of c-di-AMP. In this study, we utilized S. mitis deletion mutants of cdaA, pde1, and pde2 to analyze the role of c-di-AMP signaling in various stress responses, biofilm formation, and adhesion to eukaryotic cells. Here, we demonstrate that the Δpde1 mutant displayed a tendency toward increased susceptibility to acetic acid at pH 4.0. Deletion of cdaA increases auto-aggregation of S. mitis but reduces biofilm formation on an abiotic surface. These phenotypes are more pronounced under acidic extracellular conditions. Inactivation of pde1 or pde2 reduced the tolerance to ciprofloxacin, and UV radiation and the Δpde1 mutant was more susceptible to Triton X-100, indicating a role for c-di-AMP signaling in responses to DNA damage and cell membrane perturbation. Finally, the Δpde2 mutant displayed a tendency toward a reduced ability to adhere to oral keratinocytes. Taken together, our results indicate an important role for c-di-AMP signaling in cellular processes important for colonization of the mouth.
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Affiliation(s)
| | | | - Per Kristian Thorén Edvardsen
- Institute of Oral BiologyUniversity of OsloOsloNorway
- Present address:
Faculty of Chemistry, Biotechnology and Food ScienceNorwegian University of Life SciencesÅsNorway
| | - Roger Simm
- Institute of Oral BiologyUniversity of OsloOsloNorway
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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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Ujor VC, Lai LB, Okonkwo CC, Gopalan V, Ezeji TC. Ribozyme-Mediated Downregulation Uncovers DNA Integrity Scanning Protein A (DisA) as a Solventogenesis Determinant in Clostridium beijerinckii. Front Bioeng Biotechnol 2021; 9:669462. [PMID: 34169065 PMCID: PMC8217750 DOI: 10.3389/fbioe.2021.669462] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/04/2021] [Indexed: 11/21/2022] Open
Abstract
Carbon catabolite repression (CCR) limits microbial utilization of lignocellulose-derived pentoses. To relieve CCR in Clostridium beijerinckii NCIMB 8052, we sought to downregulate catabolite control protein A (CcpA) using the M1GS ribozyme technology. A CcpA-specific ribozyme was constructed by tethering the catalytic subunit of Escherichia coli RNase P (M1 RNA) to a guide sequence (GS) targeting CcpA mRNA (M1GSCcpA). As negative controls, the ribozyme M1GSCcpA–Sc (constructed with a scrambled GSCcpA) or the empty plasmid pMTL500E were used. With a ∼3-fold knockdown of CcpA mRNA in C. beijerinckii expressing M1GSCcpA (C. beijerinckii_M1GSCcpA) relative to both controls, a modest enhancement in mixed-sugar utilization and solvent production was achieved. Unexpectedly, C. beijerinckii_M1GSCcpA–Sc produced 50% more solvent than C. beijerinckii_pMTL500E grown on glucose + arabinose. Sequence complementarity (albeit suboptimal) suggested that M1GSCcpA–Sc could target the mRNA encoding DNA integrity scanning protein A (DisA), an expectation that was confirmed by a 53-fold knockdown in DisA mRNA levels. Therefore, M1GSCcpA–Sc was renamed M1GSDisA. Compared to C. beijerinckii_M1GSCcpA and _pMTL500E, C. beijerinckii_M1GSDisA exhibited a 7-fold decrease in the intracellular c-di-AMP level after 24 h of growth and a near-complete loss of viability upon exposure to DNA-damaging antibiotics. Alterations in c-di-AMP-mediated signaling and cell cycling likely culminate in a sporulation delay and the solvent production gains observed in C. beijerinckii_M1GSDisA. Successful knockdown of the CcpA and DisA mRNAs demonstrate the feasibility of using M1GS technology as a metabolic engineering tool for increasing butanol production in C. beijerinckii.
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Affiliation(s)
- Victor Chinomso Ujor
- Fermentation Science Program, Department of Food Science, University of Wisconsin-Madison, Madison WI, United States
| | - Lien B Lai
- Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Christopher Chukwudi Okonkwo
- Department of Animal Sciences, Ohio State Agricultural Research and Development Center, The Ohio State University, Wooster, OH, United States
| | - Venkat Gopalan
- Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Thaddeus Chukwuemeka Ezeji
- Department of Animal Sciences, Ohio State Agricultural Research and Development Center, The Ohio State University, Wooster, OH, United States
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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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Cyclic di-AMP Oversight of Counter-Ion Osmolyte Pools Impacts Intrinsic Cefuroxime Resistance in Lactococcus lactis. mBio 2021; 12:mBio.00324-21. [PMID: 33832972 PMCID: PMC8092236 DOI: 10.1128/mbio.00324-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The bacterial second messenger cyclic di-AMP (c-di-AMP) is a global regulator of potassium homeostasis and compatible solute uptake in many Gram-positive bacteria, making it essential for osmoregulation. The role that c-di-AMP plays in β-lactam resistance, however, is unclear despite being first identified a decade ago. The broadly conserved cyclic di-AMP (c-di-AMP) is a conditionally essential bacterial second messenger. The pool of c-di-AMP is fine-tuned through diadenylate cyclase and phosphodiesterase activities, and direct binding of c-di-AMP to proteins and riboswitches allows the regulation of a broad spectrum of cellular processes. c-di-AMP has a significant impact on intrinsic β-lactam antibiotic resistance in Gram-positive bacteria; however, the reason for this is currently unclear. In this work, genetic studies revealed that suppressor mutations that decrease the activity of the potassium (K+) importer KupB or the glutamine importer GlnPQ restore cefuroxime (CEF) resistance in diadenylate cyclase (cdaA) mutants of Lactococcus lactis. Metabolite analyses showed that glutamine is imported by GlnPQ and then rapidly converted to glutamate, and GlnPQ mutations or c-di-AMP negatively affects the pools of the most abundant free amino acids (glutamate and aspartate) during growth. In a high-c-di-AMP mutant, GlnPQ activity could be increased by raising the internal K+ level through the overexpression of a c-di-AMP-insensitive KupB variant. These results demonstrate that c-di-AMP reduces GlnPQ activity and, therefore, the level of the major free anions in L. lactis through its inhibition of K+ import. Excessive ion accumulation in cdaA mutants results in greater spontaneous cell lysis under hypotonic conditions, while CEF-resistant suppressors exhibit reduced cell lysis and lower osmoresistance. This work demonstrates that the overaccumulation of major counter-ion osmolyte pools in c-di-AMP-defective mutants of L. lactis causes cefuroxime sensitivity.
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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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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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Latoscha A, Drexler DJ, Witte G, Tschowri N. Assessment of Diadenylate Cyclase and c-di-AMP-phosphodiesterase Activities Using Thin-layer and Ion Exchange Chromatography. Bio Protoc 2021; 11:e3870. [PMID: 33732760 DOI: 10.21769/bioprotoc.3870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/27/2020] [Accepted: 11/02/2020] [Indexed: 11/02/2022] Open
Abstract
All living cells use cyclic nucleotides as second messengers for signal sensing and transduction. Cyclic di-3',5'-adenosine monophosphate (c-di-AMP) is primarily involved in the control of bacterial and euryarcheal osmoadaptation and is produced by diadenylate cyclases from two molecules of ATP. Specific phosphodiesterases hydrolyze c-di-AMP to the linear phosphoadenylate adenosine 5'-pApA or to AMP. Different methods including high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC) and ion exchange chromatography (IEX) can be used to determine activities of c-di-AMP-synthesizing and degrading enzymes. Here, we describe in detail the TLC and IEX methods adapted for characterization of the diadenylate cyclase DisA and the phosphodiesterase AtaC from Streptomyces venezuelae. TLC allows quick and easy separation of radioactive-labeled substrates and products, while IEX avoids utilization of potentially hazardous radioactive substrates and can be used as a good substitute if an HPLC system is not available. Unlike in TLC assays, samples cannot be analyzed in parallel by using the IEX assay, thus it is more time consuming.
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Affiliation(s)
- Andreas Latoscha
- Department of Microbiology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - David Jan Drexler
- Gene Center, Ludwig-Maximilians-Universität München, 81377 München, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, 81377 München, Germany
| | - Gregor Witte
- Gene Center, Ludwig-Maximilians-Universität München, 81377 München, Germany.,Department of Biochemistry, Ludwig-Maximilians-Universität München, 81377 München, Germany
| | - Natalia Tschowri
- Department of Microbiology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
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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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The Many Roles of the Bacterial Second Messenger Cyclic di-AMP in Adapting to Stress Cues. J Bacteriol 2020; 203:JB.00348-20. [PMID: 32839175 DOI: 10.1128/jb.00348-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Bacteria respond to changes in environmental conditions through adaptation to external cues. Frequently, bacteria employ nucleotide signaling molecules to mediate a specific, rapid response. Cyclic di-AMP (c-di-AMP) was recently discovered to be a bacterial second messenger that is essential for viability in many species. In this review, we highlight recent work that has described the roles of c-di-AMP in bacterial responses to various stress conditions. These studies show that depending on the lifestyle and environmental niche of the bacterial species, the c-di-AMP signaling network results in diverse outcomes, such as regulating osmolyte transport, controlling plant attachment, or providing a checkpoint for spore formation. c-di-AMP achieves this signaling specificity through expression of different classes of synthesis and catabolic enzymes as well as receptor proteins and RNAs, which will be summarized.
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Zaver SA, Pollock AJ, Boradia VM, Woodward JJ. A Luminescence-Based Coupled Enzyme Assay Enables High-Throughput Quantification of the Bacterial Second Messenger 3'3'-Cyclic-Di-AMP. Chembiochem 2020; 22:1030-1041. [PMID: 33142009 DOI: 10.1002/cbic.202000667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/02/2020] [Indexed: 11/12/2022]
Abstract
Cyclic dinucleotide signaling systems, which are found ubiquitously throughout nature, allow organisms to rapidly and dynamically sense and respond to alterations in their environments. In recent years, the second messenger, cyclic di-(3',5')-adenosine monophosphate (c-di-AMP), has been identified as an essential signaling molecule in a diverse array of bacterial genera. We and others have shown that defects in c-di-AMP homeostasis result in severe physiological defects and virulence attenuation in many bacterial species. Despite significant advancements in the field, there is still a major gap in the understanding of the environmental and cellular factors that influence c-di-AMP dynamics due to a lack of tools to sensitively and rapidly monitor changes in c-di-AMP levels. To address this limitation, we describe here the development of a luciferase-based coupled enzyme assay that leverages the cyclic nucleotide phosphodiesterase, CnpB, for the sensitive and high-throughput quantification of 3'3'-c-di-AMP. We also demonstrate the utility of this approach for the quantification of the cyclic oligonucleotide-based anti-phage signaling system (CBASS) effector, 3'3'-cGAMP. These findings establish CDA-Luc as a more affordable and sensitive alternative to conventional c-di-AMP detection tools with broad utility for the study of bacterial cyclic dinucleotide physiology.
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Affiliation(s)
- Shivam A Zaver
- Department of Microbiology, University of Washington, 98195, Seattle, WA, USA
| | - Alex J Pollock
- Department of Microbiology, University of Washington, 98195, Seattle, WA, USA
| | | | - Joshua J Woodward
- Department of Microbiology, University of Washington, 98195, Seattle, WA, USA
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Kundra S, Colomer-Winter C, Lemos JA. Survival of the Fittest: The Relationship of (p)ppGpp With Bacterial Virulence. Front Microbiol 2020; 11:601417. [PMID: 33343543 PMCID: PMC7744563 DOI: 10.3389/fmicb.2020.601417] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/16/2020] [Indexed: 12/11/2022] Open
Abstract
The signaling nucleotide (p)ppGpp has been the subject of intense research in the past two decades. Initially discovered as the effector molecule of the stringent response, a bacterial stress response that reprograms cell physiology during amino acid starvation, follow-up studies indicated that many effects of (p)ppGpp on cell physiology occur at levels that are lower than those needed to fully activate the stringent response, and that the repertoire of enzymes involved in (p)ppGpp metabolism is more diverse than initially thought. Of particular interest, (p)ppGpp regulation has been consistently linked to bacterial persistence and virulence, such that the scientific pursuit to discover molecules that interfere with (p)ppGpp signaling as a way to develop new antimicrobials has grown substantially in recent years. Here, we highlight contemporary studies that have further supported the intimate relationship of (p)ppGpp with bacterial virulence and studies that provided new insights into the different mechanisms by which (p)ppGpp modulates bacterial virulence.
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Affiliation(s)
- Shivani Kundra
- Department of Oral Biology, UF College of Dentistry, Gainesville, FL, United States
| | | | - José A Lemos
- Department of Oral Biology, UF College of Dentistry, Gainesville, FL, United States
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c-di-AMP Accumulation Impairs Muropeptide Synthesis in Listeria monocytogenes. J Bacteriol 2020; 202:JB.00307-20. [PMID: 33020220 DOI: 10.1128/jb.00307-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 09/17/2020] [Indexed: 12/14/2022] Open
Abstract
Cyclic di-AMP (c-di-AMP) is an essential and ubiquitous second messenger among bacteria. c-di-AMP regulates many cellular pathways through direct binding to several molecular targets in bacterial cells. c-di-AMP depletion is well known to destabilize the bacterial cell wall, resulting in increased bacteriolysis and enhanced susceptibility to cell wall targeting antibiotics. Using the human pathogen Listeria monocytogenes as a model, we found that c-di-AMP accumulation also impaired cell envelope integrity. An L. monocytogenes mutant deleted for c-di-AMP phosphodiesterases (pdeA pgpH mutant) exhibited a 4-fold increase in c-di-AMP levels and several cell wall defects. For instance, the pdeA pgpH mutant was defective for the synthesis of peptidoglycan muropeptides and was susceptible to cell wall-targeting antimicrobials. Among different muropeptide precursors, we found that the pdeA pgpH strain was particularly impaired in the synthesis of d-Ala-d-Ala, which is required to complete the pentapeptide stem associated with UDP-N-acetylmuramic acid (MurNAc). This was consistent with an increased sensitivity to d-cycloserine, which inhibits the d-alanine branch of peptidoglycan synthesis. Finally, upon examining d-Ala:d-Ala ligase (Ddl), which catalyzes the conversion of d-Ala to d-Ala-d-Ala, we found that its activity was activated by K+ Based on previous reports that c-di-AMP inhibits K+ uptake, we propose that c-di-AMP accumulation impairs peptidoglycan synthesis, partially through the deprivation of cytoplasmic K+ levels, which are required for cell wall-synthetic enzymes.IMPORTANCE The bacterial second messenger c-di-AMP is produced by a large number of bacteria and conditionally essential to many species. Conversely, c-di-AMP accumulation is also toxic to bacterial physiology and pathogenesis, but its mechanisms are largely undefined. We found that in Listeria monocytogenes, elevated c-di-AMP levels diminished muropeptide synthesis and increased susceptibility to cell wall-targeting antimicrobials. Cell wall defects might be an important mechanism for attenuated virulence in bacteria with high c-di-AMP levels.
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Louie A, Bhandula V, Portnoy DA. Secretion of c-di-AMP by Listeria monocytogenes Leads to a STING-Dependent Antibacterial Response during Enterocolitis. Infect Immun 2020; 88:e00407-20. [PMID: 33020211 PMCID: PMC7671888 DOI: 10.1128/iai.00407-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/27/2020] [Indexed: 12/24/2022] Open
Abstract
Stimulator of interferon genes (STING) acts as a cytoplasmic signaling hub of innate immunity that is activated by host-derived or bacterially derived cyclic dinucleotides. Listeria monocytogenes is a foodborne, facultative intracellular pathogen that secretes c-di-AMP and activates STING, yet the in vivo role of the STING pathway during bacterial pathogenesis remains unclear. In this study, we found that STING-deficient mice had increased weight loss and roughly 10-fold-increased systemic bacterial burden during L. monocytogenes-induced enterocolitis. Infection with a L. monocytogenes mutant impaired in c-di-AMP secretion failed to elicit a protective response, whereas a mutant with increased c-di-AMP secretion triggered enhanced protection. Type I interferon (IFN) is a major output of STING signaling; however, disrupting IFN signaling during L. monocytogenes-induced enterocolitis did not recapitulate STING deficiency. In the absence of STING, the intestinal immune response was associated with a reduced influx of inflammatory monocytes. These studies suggest that in barrier sites such as the intestinal tract, where pathogen-associated molecular patterns are abundant, cytosolic surveillance systems such as STING are well positioned to detect pathogenic bacteria.
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Affiliation(s)
- Alexander Louie
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Varaang Bhandula
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Daniel A Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
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Sultan I, Fromion V, Schbath S, Nicolas P. Statistical modelling of bacterial promoter sequences for regulatory motif discovery with the help of transcriptome data: application to Listeria monocytogenes. J R Soc Interface 2020; 17:20200600. [PMID: 33023397 PMCID: PMC7653377 DOI: 10.1098/rsif.2020.0600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 09/10/2020] [Indexed: 11/12/2022] Open
Abstract
Automatic de novo identification of the main regulons of a bacterium from genome and transcriptome data remains a challenge. To address this task, we propose a statistical model that can use information on exact positions of the transcription start sites and condition-dependent expression profiles. The central idea of this model is to improve the probabilistic representation of the promoter DNA sequences by incorporating covariates summarizing expression profiles (e.g. coordinates in projection spaces or hierarchical clustering trees). A dedicated trans-dimensional Markov chain Monte Carlo algorithm adjusts the width and palindromic properties of the corresponding position-weight matrices, the number of parameters to describe exact position relative to the transcription start site, and chooses the expression covariates relevant for each motif. All parameters are estimated simultaneously, for many motifs and many expression covariates. The method is applied to a dataset of transcription start sites and expression profiles available for Listeria monocytogenes. The results validate the approach and provide a new global view of the transcription regulatory network of this important pathogen. Remarkably, a previously unreported motif is found in promoter regions of ribosomal protein genes, suggesting a role in the regulation of growth.
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Affiliation(s)
- Ibrahim Sultan
- Université Paris-Saclay, INRAE, MaIAGE, Jouy-en-Josas, France
| | | | | | - Pierre Nicolas
- Université Paris-Saclay, INRAE, MaIAGE, Jouy-en-Josas, France
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42
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Steinchen W, Zegarra V, Bange G. (p)ppGpp: Magic Modulators of Bacterial Physiology and Metabolism. Front Microbiol 2020; 11:2072. [PMID: 33013756 PMCID: PMC7504894 DOI: 10.3389/fmicb.2020.02072] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/06/2020] [Indexed: 01/21/2023] Open
Abstract
When bacteria experience growth-limiting environmental conditions, the synthesis of the hyperphosphorylated guanosine derivatives (p)ppGpp is induced by enzymes of the RelA/SpoT homology (RSH)-type protein family. High levels of (p)ppGpp induce a process called "stringent response", a major cellular reprogramming during which ribosomal RNA (rRNA) and transfer RNA (tRNA) synthesis is downregulated, stress-related genes upregulated, messenger RNA (mRNA) stability and translation altered, and allocation of scarce resources optimized. The (p)ppGpp-mediated stringent response is thus often regarded as an all-or-nothing paradigm induced by stress. Over the past decades, several binding partners of (p)ppGpp have been uncovered displaying dissociation constants from below one micromolar to more than one millimolar and thus coincide with the accepted intracellular concentrations of (p)ppGpp under non-stringent (basal levels) and stringent conditions. This suggests that the ability of (p)ppGpp to modulate target proteins or processes would be better characterized as an unceasing continuum over a concentration range instead of being an abrupt switch of biochemical processes under specific conditions. We analyzed the reported binding affinities of (p)ppGpp targets and depicted a scheme for prioritization of modulation by (p)ppGpp. In this ranking, many enzymes of e.g., nucleotide metabolism are among the first targets to be affected by rising (p)ppGpp while more fundamental processes such as DNA replication are among the last. This preference should be part of (p)ppGpp's "magic" in the adaptation of microorganisms while still maintaining their potential for outgrowth once a stressful condition is overcome.
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Affiliation(s)
- Wieland Steinchen
- Department of Chemistry, Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | | | - Gert Bange
- Department of Chemistry, Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
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43
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Abstract
The facultative intracellular pathogen Listeria monocytogenes, like many related Firmicutes, uses the nucleotide second messenger cyclic di-AMP (c-di-AMP) to adapt to changes in nutrient availability, osmotic stress, and the presence of cell wall-acting antibiotics. In rich medium, c-di-AMP is essential; however, mutations in cbpB, the gene encoding c-di-AMP binding protein B, suppress essentiality. In this study, we identified that the reason for cbpB-dependent essentiality is through induction of the stringent response by RelA. RelA is a bifunctional RelA/SpoT homolog (RSH) that modulates levels of (p)ppGpp, a secondary messenger that orchestrates the stringent response through multiple allosteric interactions. We performed a forward genetic suppressor screen on bacteria lacking c-di-AMP to identify genomic mutations that rescued growth while cbpB was constitutively expressed and identified mutations in the synthetase domain of RelA. The synthetase domain of RelA was also identified as an interacting partner of CbpB in a yeast-2-hybrid screen. Biochemical analyses confirmed that free CbpB activates RelA while c-di-AMP inhibits its activation. We solved the crystal structure of CbpB bound and unbound to c-di-AMP and provide insight into the region important for c-di-AMP binding and RelA activation. The results of this study show that CbpB completes a homeostatic regulatory circuit between c-di-AMP and (p)ppGpp in Listeria monocytogenes.
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Rørvik GH, Liskiewicz KA, Kryuchkov F, Naemi AO, Aasheim HC, Petersen FC, Küntziger TM, Simm R. Cyclic Di-adenosine Monophosphate Regulates Metabolism and Growth in the Oral Commensal Streptococcus mitis. Microorganisms 2020; 8:microorganisms8091269. [PMID: 32825526 PMCID: PMC7570391 DOI: 10.3390/microorganisms8091269] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 08/14/2020] [Accepted: 08/18/2020] [Indexed: 01/15/2023] Open
Abstract
Cyclic di-adenosine monophosphate (c-di-AMP) has emerged as an important bacterial signaling molecule that functions both as an intracellular second messenger in bacterial cells and an extracellular ligand involved in bacteria-host cross-talk. In this study, we identify and characterize proteins involved in controlling the c-di-AMP concentration in the oral commensal and opportunistic pathogen Streptococcusmitis (S. mitis). We identified three known types of c-di-AMP turnover proteins in the genome of S. mitis CCUG31611: a CdaA-type diadenylate cyclase as well as GdpP-, and DhhP-type phosphodiesterases. Biochemical analyses of purified proteins demonstrated that CdaA synthesizes c-di-AMP from ATP whereas both phosphodiesterases can utilize c-di-AMP as well as the intermediary metabolite of c-di-AMP hydrolysis 5'-phosphadenylyl-adenosine (pApA) as substrate to generate AMP, albeit at different catalytic efficiency. Using deletion mutants of each of the genes encoding c-di-AMP turnover proteins, we show by high resolution MS/MS that the intracellular concentration of c-di-AMP is increased in deletion mutants of the phosphodiesterases and non-detectable in the cdaA-mutant. We also detected pApA in mutants of the DhhP-type phosphodiesterase. Low and high levels of c-di-AMP were associated with longer and shorter chains of S. mitis, respectively indicating a role in regulation of cell division. The deletion mutant of the DhhP-type phosphodiesterase displayed slow growth and reduced rate of glucose metabolism.
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Affiliation(s)
- Gro Herredsvela Rørvik
- Institute of Oral Biology, University of Oslo, 0316 Oslo, Norway; (G.H.R.); (K.A.L.); (A.-O.N.); (H.-C.A.); (F.C.P.); (T.M.K.)
| | - Krystyna Anna Liskiewicz
- Institute of Oral Biology, University of Oslo, 0316 Oslo, Norway; (G.H.R.); (K.A.L.); (A.-O.N.); (H.-C.A.); (F.C.P.); (T.M.K.)
| | - Fedor Kryuchkov
- Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway;
| | - Ali-Oddin Naemi
- Institute of Oral Biology, University of Oslo, 0316 Oslo, Norway; (G.H.R.); (K.A.L.); (A.-O.N.); (H.-C.A.); (F.C.P.); (T.M.K.)
| | - Hans-Christian Aasheim
- Institute of Oral Biology, University of Oslo, 0316 Oslo, Norway; (G.H.R.); (K.A.L.); (A.-O.N.); (H.-C.A.); (F.C.P.); (T.M.K.)
| | - Fernanda C. Petersen
- Institute of Oral Biology, University of Oslo, 0316 Oslo, Norway; (G.H.R.); (K.A.L.); (A.-O.N.); (H.-C.A.); (F.C.P.); (T.M.K.)
| | - Thomas M. Küntziger
- Institute of Oral Biology, University of Oslo, 0316 Oslo, Norway; (G.H.R.); (K.A.L.); (A.-O.N.); (H.-C.A.); (F.C.P.); (T.M.K.)
| | - Roger Simm
- Institute of Oral Biology, University of Oslo, 0316 Oslo, Norway; (G.H.R.); (K.A.L.); (A.-O.N.); (H.-C.A.); (F.C.P.); (T.M.K.)
- Correspondence:
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Cesinger MR, Thomason MK, Edrozo MB, Halsey CR, Reniere ML. Listeria monocytogenes SpxA1 is a global regulator required to activate genes encoding catalase and heme biosynthesis enzymes for aerobic growth. Mol Microbiol 2020; 114:230-243. [PMID: 32255216 PMCID: PMC7496741 DOI: 10.1111/mmi.14508] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 12/24/2022]
Abstract
An imbalance of cellular oxidants and reductants causes redox stress, which must be rapidly detected to restore homeostasis. In bacteria, the Firmicutes encode conserved Spx-family transcriptional regulators that modulate transcription in response to redox stress. SpxA1 is an Spx-family orthologue in the intracellular pathogen Listeria monocytogenes that is essential for aerobic growth and pathogenesis. Here, we investigated the role of SpxA1 in growth and virulence by identifying genes regulated by SpxA1 in broth and during macrophage infection. We found SpxA1-activated genes encoding heme biosynthesis enzymes and catalase (kat) were required for L. monocytogenes aerobic growth in rich medium. An Spx-recognition motif previously defined in Bacillus subtilis was identified in the promoters of SpxA1-activated genes and proved necessary for the proper activation of two genes, indicating this regulation by SpxA1 is likely direct. Together, these findings elucidated the mechanism of spxA1 essentiality in vitro and demonstrated that SpxA1 is required for basal expression of scavenging enzymes to combat redox stress generated in the presence of oxygen.
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Affiliation(s)
- Monica R. Cesinger
- Department of MicrobiologySchool of MedicineUniversity of WashingtonSeattleWAUSA
| | - Maureen K. Thomason
- Department of MicrobiologySchool of MedicineUniversity of WashingtonSeattleWAUSA
| | - Mauna B. Edrozo
- Department of MicrobiologySchool of MedicineUniversity of WashingtonSeattleWAUSA
| | - Cortney R. Halsey
- Department of MicrobiologySchool of MedicineUniversity of WashingtonSeattleWAUSA
| | - Michelle L. Reniere
- Department of MicrobiologySchool of MedicineUniversity of WashingtonSeattleWAUSA
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Abstract
The second messenger molecule cyclic di-AMP (c-di-AMP) is formed by many bacteria and archaea. In many species that produce c-di-AMP, this second messenger is essential for viability on rich medium. Recent research has demonstrated that c-di-AMP binds to a large number of proteins and riboswitches, which are often involved in potassium and osmotic homeostasis. c-di-AMP becomes dispensable if the bacteria are cultivated on minimal media with low concentrations of osmotically active compounds. Thus, the essentiality of c-di-AMP does not result from an interaction with a single essential target but rather from the multilevel control of complex homeostatic processes. This review summarizes current knowledge on the homeostasis of c-di-AMP and its function(s) in the control of cellular processes.
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Affiliation(s)
- Jörg Stülke
- Department of General Microbiology, Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077 Göttingen, Germany;
| | - Larissa Krüger
- Department of General Microbiology, Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077 Göttingen, Germany;
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47
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Two Ways To Convert a Low-Affinity Potassium Channel to High Affinity: Control of Bacillus subtilis KtrCD by Glutamate. J Bacteriol 2020; 202:JB.00138-20. [PMID: 32253343 DOI: 10.1128/jb.00138-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 04/01/2020] [Indexed: 02/06/2023] Open
Abstract
Potassium and glutamate are the major cation and anion, respectively, in every living cell. Due to the high concentrations of both ions, the cytoplasm of all cells can be regarded as a potassium glutamate solution. This implies that the concentrations of both ions need to be balanced. While the control of potassium uptake by glutamate is well established for eukaryotic cells, much less is known about the mechanisms that link potassium homeostasis to glutamate availability in bacteria. Here, we have discovered that the availability of glutamate strongly decreases the minimal external potassium concentration required for the highly abundant Bacillus subtilis potassium channel KtrCD to accumulate potassium. In contrast, the inducible KtrAB and KimA potassium uptake systems have high apparent affinities for potassium even in the absence of glutamate. Experiments with mutant strains revealed that the KtrD subunit responds to the presence of glutamate. For full activity, KtrD synergistically requires the presence of the regulatory subunit KtrC and of glutamate. The analysis of suppressor mutants of a strain that has KtrCD as the only potassium uptake system and that experiences severe potassium starvation identified a mutation in the ion selectivity filter of KtrD (Gly282 to Val) that similarly results in a strongly glutamate-independent increase of the apparent affinity for potassium. Thus, this work has identified two conditions that increase the apparent affinity of KtrCD for potassium, i.e., external glutamate and the acquisition of a single point mutation in KtrD.IMPORTANCE In each living cell, potassium is required for maintaining the intracellular pH and for the activity of essential enzymes. Like most other bacteria, Bacillus subtilis possesses multiple low- and high-affinity potassium uptake systems. Their activity is regulated by the second messenger cyclic di-AMP. Moreover, the pools of the most abundant ions potassium and glutamate must be balanced. We report two conditions under which the low-affinity potassium channel KtrCD is able to mediate potassium uptake at low external potassium concentrations: physiologically, the presence of glutamate results in a severely increased potassium uptake. Moreover, this is achieved by a mutation affecting the selectivity filter of the KtrD channel. These results highlight the integration between potassium and glutamate homeostasis in bacteria.
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48
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He J, Yin W, Galperin MY, Chou SH. Cyclic di-AMP, a second messenger of primary importance: tertiary structures and binding mechanisms. Nucleic Acids Res 2020; 48:2807-2829. [PMID: 32095817 DOI: 10.1093/nar/gkaa112] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/09/2020] [Accepted: 02/21/2020] [Indexed: 12/12/2022] Open
Abstract
Cyclic diadenylate (c-di-AMP) is a widespread second messenger in bacteria and archaea that is involved in the maintenance of osmotic pressure, response to DNA damage, and control of central metabolism, biofilm formation, acid stress resistance, and other functions. The primary importance of c-di AMP stems from its essentiality for many bacteria under standard growth conditions and the ability of several eukaryotic proteins to sense its presence in the cell cytoplasm and trigger an immune response by the host cells. We review here the tertiary structures of the domains that regulate c-di-AMP synthesis and signaling, and the mechanisms of c-di-AMP binding, including the principal conformations of c-di-AMP, observed in various crystal structures. We discuss how these c-di-AMP molecules are bound to the protein and riboswitch receptors and what kinds of interactions account for the specific high-affinity binding of the c-di-AMP ligand. We describe seven kinds of non-covalent-π interactions between c-di-AMP and its receptor proteins, including π-π, C-H-π, cation-π, polar-π, hydrophobic-π, anion-π and the lone pair-π interactions. We also compare the mechanisms of c-di-AMP and c-di-GMP binding by the respective receptors that allow these two cyclic dinucleotides to control very different biological functions.
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Affiliation(s)
- Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P. R. China
| | - Wen Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P. R. China
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Shan-Ho Chou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P. R. China.,Institute of Biochemistry and Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan, Republic of China
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Gibhardt J, Heidemann JL, Bremenkamp R, Rosenberg J, Seifert R, Kaever V, Ficner R, Commichau FM. An extracytoplasmic protein and a moonlighting enzyme modulate synthesis of c-di-AMP in Listeria monocytogenes. Environ Microbiol 2020; 22:2771-2791. [PMID: 32250026 DOI: 10.1111/1462-2920.15008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 03/17/2020] [Accepted: 03/31/2020] [Indexed: 01/06/2023]
Abstract
The second messenger cyclic di-AMP (c-di-AMP) is essential for growth of many bacteria because it controls osmolyte homeostasis. c-di-AMP can regulate the synthesis of potassium uptake systems in some bacteria and it also directly inhibits and activates potassium import and export systems, respectively. Therefore, c-di-AMP production and degradation have to be tightly regulated depending on the environmental osmolarity. The Gram-positive pathogen Listeria monocytogenes relies on the membrane-bound diadenylate cyclase CdaA for c-di-AMP production and degrades the nucleotide with two phosphodiesterases. While the enzymes producing and degrading the dinucleotide have been reasonably well examined, the regulation of c-di-AMP production is not well understood yet. Here we demonstrate that the extracytoplasmic regulator CdaR interacts with CdaA via its transmembrane helix to modulate c-di-AMP production. Moreover, we show that the phosphoglucosamine mutase GlmM forms a complex with CdaA and inhibits the diadenylate cyclase activity in vitro. We also found that GlmM inhibits c-di-AMP production in L. monocytogenes when the bacteria encounter osmotic stress. Thus, GlmM is the major factor controlling the activity of CdaA in vivo. GlmM can be assigned to the class of moonlighting proteins because it is active in metabolism and adjusts the cellular turgor depending on environmental osmolarity.
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Affiliation(s)
- Johannes Gibhardt
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany.,FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany
| | - Jana L Heidemann
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, University of Goettingen, 37077, Göttingen, Germany
| | - Rica Bremenkamp
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Jonathan Rosenberg
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Roland Seifert
- Institute of Pharmacology & Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Volkhard Kaever
- Institute of Pharmacology & Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, University of Goettingen, 37077, Göttingen, Germany
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany
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50
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He J, Yin W, Galperin MY, Chou SH. Cyclic di-AMP, a second messenger of primary importance: tertiary structures and binding mechanisms. Nucleic Acids Res 2020. [PMID: 32095817 DOI: 10.1093/nar/gkaa112"] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cyclic diadenylate (c-di-AMP) is a widespread second messenger in bacteria and archaea that is involved in the maintenance of osmotic pressure, response to DNA damage, and control of central metabolism, biofilm formation, acid stress resistance, and other functions. The primary importance of c-di AMP stems from its essentiality for many bacteria under standard growth conditions and the ability of several eukaryotic proteins to sense its presence in the cell cytoplasm and trigger an immune response by the host cells. We review here the tertiary structures of the domains that regulate c-di-AMP synthesis and signaling, and the mechanisms of c-di-AMP binding, including the principal conformations of c-di-AMP, observed in various crystal structures. We discuss how these c-di-AMP molecules are bound to the protein and riboswitch receptors and what kinds of interactions account for the specific high-affinity binding of the c-di-AMP ligand. We describe seven kinds of non-covalent-π interactions between c-di-AMP and its receptor proteins, including π-π, C-H-π, cation-π, polar-π, hydrophobic-π, anion-π and the lone pair-π interactions. We also compare the mechanisms of c-di-AMP and c-di-GMP binding by the respective receptors that allow these two cyclic dinucleotides to control very different biological functions.
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Affiliation(s)
- Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P. R. China
| | - Wen Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P. R. China
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Shan-Ho Chou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, P. R. China.,Institute of Biochemistry and Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan, Republic of China
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