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Gibhardt J, Hoffmann G, Turdiev A, Wang M, Lee VT, Commichau FM. c-di-AMP assists osmoadaptation by regulating the Listeria monocytogenes potassium transporters KimA and KtrCD. J Biol Chem 2019; 294:16020-16033. [PMID: 31506295 DOI: 10.1074/jbc.ra119.010046] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/03/2019] [Indexed: 12/30/2022] Open
Abstract
Many bacteria and some archaea produce the second messenger cyclic diadenosine monophosphate (c-di-AMP). c-di-AMP controls the uptake of osmolytes in Firmicutes, including the human pathogen Listeria monocytogenes, making it essential for growth. c-di-AMP is known to directly regulate several potassium channels involved in osmolyte transport in species such as Bacillus subtilis and Streptococcus pneumoniae, but whether this same mechanism is involved in L. monocytogenes, or even whether similar ion channels were present, was not known. Here, we have identified and characterized the putative L. monocytogenes' potassium transporters KimA, KtrCD, and KdpABC. We demonstrate that Escherichia coli expressing KimA and KtrCD, but not KdpABC, transport potassium into the cell, and both KimA and KtrCD are inhibited by c-di-AMP in vivo For KimA, c-di-AMP-dependent regulation requires the C-terminal domain. In vitro assays demonstrated that the dinucleotide binds to the cytoplasmic regulatory subunit KtrC and to the KdpD sensor kinase of the KdpDE two-component system, which in Staphylococcus aureus regulates the corresponding KdpABC transporter. Finally, we also show that S. aureus contains a homolog of KimA, which mediates potassium transport. Thus, the c-di-AMP-dependent control of systems involved in potassium homeostasis seems to be conserved in phylogenetically related bacteria. Surprisingly, the growth of an L. monocytogenes mutant lacking the c-di-AMP-synthesizing enzyme cdaA is only weakly inhibited by potassium. Thus, the physiological impact of the c-di-AMP-dependent control of potassium uptake seems to be less pronounced in L. monocytogenes than in other Firmicutes.
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Affiliation(s)
- Johannes Gibhardt
- Department of General Microbiology, Institute for Microbiology and Genetics, Georg-August University Göttingen, D-37077 Göttingen, Germany
| | - Gregor Hoffmann
- Department of General Microbiology, Institute for Microbiology and Genetics, Georg-August University Göttingen, D-37077 Göttingen, Germany
| | - Asan Turdiev
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
| | - Mengyi Wang
- Department of General Microbiology, Institute for Microbiology and Genetics, Georg-August University Göttingen, D-37077 Göttingen, Germany
| | - Vincent T Lee
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
| | - Fabian M Commichau
- Department of General Microbiology, Institute for Microbiology and Genetics, Georg-August University Göttingen, D-37077 Göttingen, Germany
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The Second Messenger c-di-AMP Regulates Diverse Cellular Pathways Involved in Stress Response, Biofilm Formation, Cell Wall Homeostasis, SpeB Expression, and Virulence in Streptococcus pyogenes. Infect Immun 2019; 87:IAI.00147-19. [PMID: 30936159 DOI: 10.1128/iai.00147-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 03/25/2019] [Indexed: 02/07/2023] Open
Abstract
Cyclic di-AMP (c-di-AMP) is a recently discovered second messenger in bacteria. The cellular level of c-di-AMP in Streptococcus pyogenes is predicted to be controlled by the synthase DacA and two putative phosphodiesterases, GdpP and Pde2. To investigate the role of c-di-AMP in S. pyogenes, we generated null mutants in each of these proteins by gene deletion. Unlike those in other Gram-positive pathogens such as Staphylococcus aureus and Listeria monocytogenes, DacA in S. pyogenes was not essential for growth in rich media. The DacA null mutant presented a growth defect that manifested through an increased lag time, produced no detectable biofilm, and displayed increased susceptibility toward environmental stressors such as high salt, low pH, reactive oxygen radicals, and cell wall-targeting antibiotics, suggesting that c-di-AMP plays significant roles in crucial cellular processes involved in stress management. The Pde2 null mutant exhibited a lower growth rate and increased biofilm formation, and interestingly, these phenotypes were distinct from those of the null mutant of GdpP, suggesting that Pde2 and GdpP play distinctive roles in c-di-AMP signaling. DacA and Pde2 were critical to the production of the virulence factor SpeB and to the overall virulence of S. pyogenes, as both DacA and Pde2 null mutants were highly attenuated in a mouse model of subcutaneous infection. Collectively, these results show that c-di-AMP is an important global regulator and is required for a proper response to stress and for virulence in S. pyogenes, suggesting that its signaling pathway could be an attractive antivirulence drug target against S. pyogenes infections.
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Wang X, Cai X, Ma H, Yin W, Zhu L, Li X, Lim HM, Chou SH, He J. A c-di-AMP riboswitch controlling kdpFABC operon transcription regulates the potassium transporter system in Bacillus thuringiensis. Commun Biol 2019; 2:151. [PMID: 31044176 PMCID: PMC6488665 DOI: 10.1038/s42003-019-0414-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/28/2019] [Indexed: 11/09/2022] Open
Abstract
The intracellular K+ level in bacteria is strictly controlled by K+ uptake and efflux systems. Among these, KdpFABC is a high-affinity K+ transporter system that is generally activated by the KdpDE two-component system in response to K+ limitation stress. However, the regulatory mechanism remains obscure in bacteria lacking the kdpDE genes. Here we report that the transcription of a kdpFABC operon is distinctively regulated by a cyclic diadenylate monophosphate (c-di-AMP) riboswitch located at the 5'-untranslated region of kdp transcript, and binding of c-di-AMP to the riboswitch promotes its intrinsic termination that blocks the kdpFABC transcription. Further, the intracellular c-di-AMP concentration was found to decrease under the K+ limitation stress, leading to transcriptional read-through over the terminator to allow kdpFABC expression. This regulatory element is found predominantly in the Bacillus cereus group and correlate well with the K+ and c-di-AMP homeostasis that affects a variety of crucial cellular functions.
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Affiliation(s)
- Xun Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070 PR China
| | - Xia Cai
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070 PR China
| | - Hongdan Ma
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070 PR China
| | - Wen Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070 PR China
| | - Li Zhu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070 PR China
| | - Xinfeng Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070 PR China
| | - Heon M. Lim
- Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 305-764 Republic of Korea
| | - Shan-Ho Chou
- Institute of Biochemistry and Agricultural Biotechnology Center, National Chung Hsing University, Taichung, 40227 Taiwan
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070 PR China
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The KupA and KupB Proteins of Lactococcus lactis IL1403 Are Novel c-di-AMP Receptor Proteins Responsible for Potassium Uptake. J Bacteriol 2019; 201:JB.00028-19. [PMID: 30745376 DOI: 10.1128/jb.00028-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 02/04/2019] [Indexed: 12/13/2022] Open
Abstract
Cyclic di-AMP (c-di-AMP) is a second messenger involved in diverse metabolic processes, including osmolyte uptake, cell wall homeostasis, and antibiotic and heat resistance. In Lactococcus lactis, a lactic acid bacterium which is used in the dairy industry and as a cell factory in biotechnological processes, the only reported interaction partners of c-di-AMP are the pyruvate carboxylase and BusR, the transcription regulator of the busAB operon for glycine betaine uptake. However, recent studies uncovered a major role of c-di-AMP in the control of potassium homeostasis, and potassium is the signal that triggers c-di-AMP synthesis. In this study, we have identified KupA and KupB, which belong to the Kup/HAK/KT family, as novel c-di-AMP binding proteins. Both proteins are high-affinity potassium transporters, and their transport activities are inhibited by binding of c-di-AMP. Thus, in addition to the well-studied Ktr/Trk potassium channels, KupA and KupB represent a second class of potassium transporters that are subject to inhibition by c-di-AMP.IMPORTANCE Potassium is an essential ion in every living cell. Even though potassium is the most abundant cation in cells, its accumulation can be toxic. Therefore, the level of potassium has to be tightly controlled. In many Gram-positive bacteria, the second messenger cyclic di-AMP plays a key role in the control of potassium homeostasis by binding to potassium transporters and regulatory proteins and RNA molecules. In the lactic acid bacterium Lactococcus lactis, none of these conserved c-di-AMP-responsive molecules are present. In this study, we demonstrate that the KupA and KupB proteins of L. lactis IL1403 are high-affinity potassium transporters and that their transport activity is inhibited by the second messenger c-di-AMP.
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Braun F, Thomalla L, van der Does C, Quax TEF, Allers T, Kaever V, Albers SV. Cyclic nucleotides in archaea: Cyclic di-AMP in the archaeon Haloferax volcanii and its putative role. Microbiologyopen 2019; 8:e00829. [PMID: 30884174 PMCID: PMC6741144 DOI: 10.1002/mbo3.829] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/06/2019] [Accepted: 02/06/2019] [Indexed: 12/27/2022] Open
Abstract
The role of cyclic nucleotides as second messengers for intracellular signal transduction has been well described in bacteria. One recently discovered bacterial second messenger is cyclic di‐adenylate monophosphate (c‐di‐AMP), which has been demonstrated to be essential in bacteria. Compared to bacteria, significantly less is known about second messengers in archaea. This study presents the first evidence of in vivo presence of c‐di‐AMP in an archaeon. The model organism Haloferax volcanii was demonstrated to produce c‐di‐AMP. Its genome encodes one diadenylate cyclase (DacZ) which was shown to produce c‐di‐AMP in vitro. Similar to bacteria, the dacZ gene is essential and homologous overexpression of DacZ leads to cell death, suggesting the need for tight regulation of c‐di‐AMP levels. Such tight regulation often indicates the control of important regulatory processes. A central target of c‐di‐AMP signaling in bacteria is cellular osmohomeostasis. The results presented here suggest a comparable function in H. volcanii. A strain with decreased c‐di‐AMP levels exhibited an increased cell area in hypo‐salt medium, implying impaired osmoregulation. In summary, this study expands the field of research on c‐di‐AMP and its physiological function to archaea and indicates that osmoregulation is likely to be a common function of c‐di‐AMP in bacteria and archaea.
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Affiliation(s)
- Frank Braun
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Freiburg, Germany
| | - Laura Thomalla
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Freiburg, Germany
| | - Chris van der Does
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Freiburg, Germany
| | - Tessa E F Quax
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Freiburg, Germany
| | - Thorsten Allers
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - Volkhard Kaever
- Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Freiburg, Germany
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Cortesão M, Fuchs FM, Commichau FM, Eichenberger P, Schuerger AC, Nicholson WL, Setlow P, Moeller R. Bacillus subtilis Spore Resistance to Simulated Mars Surface Conditions. Front Microbiol 2019; 10:333. [PMID: 30863384 PMCID: PMC6399134 DOI: 10.3389/fmicb.2019.00333] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/08/2019] [Indexed: 11/13/2022] Open
Abstract
In a Mars exploration scenario, knowing if and how highly resistant Bacillus subtilis spores would survive on the Martian surface is crucial to design planetary protection measures and avoid false positives in life-detection experiments. Therefore, in this study a systematic screening was performed to determine whether B. subtilis spores could survive an average day on Mars. For that, spores from two comprehensive sets of isogenic B. subtilis mutant strains, defective in DNA protection or repair genes, were exposed to 24 h of simulated Martian atmospheric environment with or without 8 h of Martian UV radiation [M(+)UV and M(-)UV, respectively]. When exposed to M(+)UV, spore survival was dependent on: (1) core dehydration maintenance, (2) protection of DNA by α/β-type small acid soluble proteins (SASP), and (3) removal and repair of the major UV photoproduct (SP) in spore DNA. In turn, when exposed to M(-)UV, spore survival was mainly dependent on protection by the multilayered spore coat, and DNA double-strand breaks represent the main lesion accumulated. Bacillus subtilis spores were able to survive for at least a limited time in a simulated Martian environment, both with or without solar UV radiation. Moreover, M(-)UV-treated spores exhibited survival rates significantly higher than the M(+)UV-treated spores. This suggests that on a real Martian surface, radiation shielding of spores (e.g., by dust, rocks, or spacecraft surface irregularities) might significantly extend survival rates. Mutagenesis were strongly dependent on the functionality of all structural components with small acid-soluble spore proteins, coat layers and dipicolinic acid as key protectants and efficiency DNA damage removal by AP endonucleases (ExoA and Nfo), non-homologous end joining (NHEJ), mismatch repair (MMR) and error-prone translesion synthesis (TLS). Thus, future efforts should focus on: (1) determining the DNA damage in wild-type spores exposed to M(+/-)UV and (2) assessing spore survival and viability with shielding of spores via Mars regolith and other relevant materials.
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Affiliation(s)
- Marta Cortesão
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Felix M Fuchs
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Fabian M Commichau
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Patrick Eichenberger
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY, United States
| | - Andrew C Schuerger
- Department of Plant Pathology, Space Life Sciences Laboratory, University of Florida, Merritt Island, FL, United States
| | - Wayne L Nicholson
- Department of Microbiology and Cell Science, Space Life Sciences Laboratory, University of Florida, Merritt Island, FL, United States
| | - Peter Setlow
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, United States
| | - Ralf Moeller
- Space Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
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Increased Intracellular Cyclic di-AMP Levels Sensitize Streptococcus gallolyticus subsp. gallolyticus to Osmotic Stress and Reduce Biofilm Formation and Adherence on Intestinal Cells. J Bacteriol 2019; 201:JB.00597-18. [PMID: 30617242 PMCID: PMC6398277 DOI: 10.1128/jb.00597-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/20/2018] [Indexed: 12/31/2022] Open
Abstract
Streptococcus gallolyticus is an opportunistic pathogen responsible for septicemia and endocarditis in the elderly and is also strongly associated with colorectal cancer. S. gallolyticus can form biofilms, express specific pili to colonize the host tissues, and produce a specific bacteriocin allowing killing of commensal bacteria in the murine colon. Nevertheless, how the expression of these colonization factors is regulated remains largely unknown. Here, we show that c-di-AMP plays pleiotropic roles in S. gallolyticus, controlling the tolerance to osmotic stress, cell size, biofilm formation on abiotic surfaces, adherence and cell aggregation on human intestinal cells, expression of Pil3 pilus, and production of bacteriocin. This study indicates that c-di-AMP may constitute a key regulatory molecule for S. gallolyticus host colonization and pathogenesis. Cyclic di-AMP is a recently identified second messenger exploited by a number of Gram-positive bacteria to regulate important biological processes. Here, we studied the phenotypic alterations induced by the increased intracellular c-di-AMP levels in Streptococcus gallolyticus, an opportunistic pathogen responsible for septicemia and endocarditis in the elderly. We report that an S. gallolyticus c-di-AMP phosphodiesterase gdpP knockout mutant, which displays a 1.5-fold higher intracellular c-di-AMP levels than the parental strain UCN34, is more sensitive to osmotic stress and is morphologically smaller than the parental strain. Unexpectedly, we found that a higher level of c-di-AMP reduced biofilm formation of S. gallolyticus on abiotic surfaces and reduced adherence and cell aggregation on human intestinal cells. A genome-wide transcriptomic analysis indicated that c-di-AMP regulates many biological processes in S. gallolyticus, including the expression of various ABC transporters and disease-associated genes encoding bacteriocin and Pil3 pilus. Complementation of the gdpP in-frame deletion mutant with a plasmid carrying gdpP in trans from its native promoter restored bacterial morphology, tolerance to osmotic stress, biofilm formation, adherence to intestinal cells, bacteriocin production, and Pil3 pilus expression. Our results indicate that c-di-AMP is a pleiotropic signaling molecule in S. gallolyticus that may be important for S. gallolyticus pathogenesis. IMPORTANCEStreptococcus gallolyticus is an opportunistic pathogen responsible for septicemia and endocarditis in the elderly and is also strongly associated with colorectal cancer. S. gallolyticus can form biofilms, express specific pili to colonize the host tissues, and produce a specific bacteriocin allowing killing of commensal bacteria in the murine colon. Nevertheless, how the expression of these colonization factors is regulated remains largely unknown. Here, we show that c-di-AMP plays pleiotropic roles in S. gallolyticus, controlling the tolerance to osmotic stress, cell size, biofilm formation on abiotic surfaces, adherence and cell aggregation on human intestinal cells, expression of Pil3 pilus, and production of bacteriocin. This study indicates that c-di-AMP may constitute a key regulatory molecule for S. gallolyticus host colonization and pathogenesis.
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Determination of the Global Pattern of Gene Expression in Yeast Cells by Intracellular Levels of Guanine Nucleotides. mBio 2019; 10:mBio.02500-18. [PMID: 30670615 PMCID: PMC6343037 DOI: 10.1128/mbio.02500-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
This paper investigates whether, independently of the supply of any specific nutrient, gene transcription responds to the energy status of the cell by monitoring ATP and GTP levels. Short pathways for the inducible and futile consumption of ATP or GTP were engineered into the yeast Saccharomyces cerevisiae, and the effect of an increased demand for these purine nucleotides on gene transcription was analyzed. The resulting changes in transcription were most consistently associated with changes in GTP and GEC levels, although the reprogramming in gene expression during glucose repression is sensitive to adenine nucleotide levels. The results show that GTP levels play a central role in determining how genes act to respond to changes in energy supply and that any comprehensive understanding of the control of eukaryotic gene expression requires the elucidation of how changes in guanine nucleotide abundance are sensed and transduced to alter the global pattern of transcription. Correlations between gene transcription and the abundance of high-energy purine nucleotides in Saccharomyces cerevisiae have often been noted. However, there has been no systematic investigation of this phenomenon in the absence of confounding factors such as nutrient status and growth rate, and there is little hard evidence for a causal relationship. Whether transcription is fundamentally responsive to prevailing cellular energetic conditions via sensing of intracellular purine nucleotides, independently of specific nutrition, remains an important question. The controlled nutritional environment of chemostat culture revealed a strong correlation between ATP and GTP abundance and the transcription of genes required for growth. Short pathways for the inducible and futile consumption of ATP or GTP were engineered into S. cerevisiae, permitting analysis of the transcriptional effect of an increased demand for these nucleotides. During steady-state growth using the fermentable carbon source glucose, the futile consumption of ATP led to a decrease in intracellular ATP concentration but an increase in GTP and the guanylate energy charge (GEC). Expression of transcripts encoding proteins involved in ribosome biogenesis, and those controlled by promoters subject to SWI/SNF-dependent chromatin remodelling, was correlated with these nucleotide pool changes. Similar nucleotide abundance changes were observed using a nonfermentable carbon source, but an effect on the growth-associated transcriptional programme was absent. Induction of the GTP-cycling pathway had only marginal effects on nucleotide abundance and gene transcription. The transcriptional response of respiring cells to glucose was dampened in chemostats induced for ATP cycling, but not GTP cycling, and this was primarily associated with altered adenine nucleotide levels.
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Hernández-Morales R, Becerra A, Lazcano A. Alarmones as Vestiges of a Bygone RNA World. J Mol Evol 2019; 87:37-51. [PMID: 30604017 DOI: 10.1007/s00239-018-9883-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 12/15/2018] [Indexed: 12/11/2022]
Abstract
All known alarmones are ribonucleotides or ribonucleotide derivatives that are synthesized when cells are under stress conditions, triggering a stringent response that affects major processes such as replication, gene expression, and metabolism. The ample phylogenetic distribution of alarmones (e.g., cAMP, Ap(n)A, cGMP, AICAR, and ZTP) suggests that they are very ancient molecules that may have already been present in cellular systems prior to the evolutionary divergence of the Archaea, Bacteria, and Eukarya domains. Their chemical structure, wide biological distribution, and functional role in highly conserved cellular processes support the possibility that these modified nucleotides are molecular fossils of an epoch in the evolution of chemical signaling and metabolite sensing during which RNA molecules played a much more conspicuous role in biological catalysis and genetic information.
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Affiliation(s)
- Ricardo Hernández-Morales
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Cd. Universitaria, 04510, Mexico City, Mexico
| | - Arturo Becerra
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Cd. Universitaria, 04510, Mexico City, Mexico
| | - Antonio Lazcano
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Cd. Universitaria, 04510, Mexico City, Mexico. .,Miembro de El Colegio Nacional, Donceles 104, Centro Histórico, 06000, Mexico City, Mexico.
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Tosi T, Hoshiga F, Millership C, Singh R, Eldrid C, Patin D, Mengin-Lecreulx D, Thalassinos K, Freemont P, Gründling A. Inhibition of the Staphylococcus aureus c-di-AMP cyclase DacA by direct interaction with the phosphoglucosamine mutase GlmM. PLoS Pathog 2019; 15:e1007537. [PMID: 30668586 PMCID: PMC6368335 DOI: 10.1371/journal.ppat.1007537] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/08/2019] [Accepted: 12/18/2018] [Indexed: 02/05/2023] Open
Abstract
c-di-AMP is an important second messenger molecule that plays a pivotal role in regulating fundamental cellular processes, including osmotic and cell wall homeostasis in many Gram-positive organisms. In the opportunistic human pathogen Staphylococcus aureus, c-di-AMP is produced by the membrane-anchored DacA enzyme. Inactivation of this enzyme leads to a growth arrest under standard laboratory growth conditions and a re-sensitization of methicillin-resistant S. aureus (MRSA) strains to ß-lactam antibiotics. The gene coding for DacA is part of the conserved three-gene dacA/ybbR/glmM operon that also encodes the proposed DacA regulator YbbR and the essential phosphoglucosamine mutase GlmM, which is required for the production of glucosamine-1-phosphate, an early intermediate of peptidoglycan synthesis. These three proteins are thought to form a complex in vivo and, in this manner, help to fine-tune the cellular c-di-AMP levels. To further characterize this important regulatory complex, we conducted a comprehensive structural and functional analysis of the S. aureus DacA and GlmM enzymes by determining the structures of the S. aureus GlmM enzyme and the catalytic domain of DacA. Both proteins were found to be dimers in solution as well as in the crystal structures. Further site-directed mutagenesis, structural and enzymatic studies showed that multiple DacA dimers need to interact for enzymatic activity. We also show that DacA and GlmM form a stable complex in vitro and that S. aureus GlmM, but not Escherichia coli or Pseudomonas aeruginosa GlmM, acts as a strong inhibitor of DacA function without the requirement of any additional cellular factor. Based on Small Angle X-ray Scattering (SAXS) data, a model of the complex revealed that GlmM likely inhibits DacA by masking the active site of the cyclase and preventing higher oligomer formation. Together these results provide an important mechanistic insight into how c-di-AMP production can be regulated in the cell.
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Affiliation(s)
- Tommaso Tosi
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Fumiya Hoshiga
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Charlotte Millership
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Rahul Singh
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Charles Eldrid
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, Malet Street, London, United Kingdom
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Delphine Patin
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ Paris-Sud and Université Paris-Saclay, Gif-sur-Yvette, France
| | - Dominique Mengin-Lecreulx
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ Paris-Sud and Université Paris-Saclay, Gif-sur-Yvette, France
| | - Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, Malet Street, London, United Kingdom
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Paul Freemont
- Section of Structural Biology, Department of Medicine, Imperial College London, London, United Kingdom
| | - Angelika Gründling
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
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Making and Breaking of an Essential Poison: the Cyclases and Phosphodiesterases That Produce and Degrade the Essential Second Messenger Cyclic di-AMP in Bacteria. J Bacteriol 2018; 201:JB.00462-18. [PMID: 30224435 DOI: 10.1128/jb.00462-18] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cyclic di-AMP is a second-messenger nucleotide that is produced by many bacteria and some archaea. Recent work has shown that c-di-AMP is unique among the signaling nucleotides, as this molecule is in many bacteria both essential on one hand and toxic upon accumulation on the other. Moreover, in bacteria, like Bacillus subtilis, c-di-AMP controls a biological process, potassium homeostasis, by binding both potassium transporters and riboswitch molecules in the mRNAs that encode the potassium transporters. In addition to the control of potassium homeostasis, c-di-AMP has been implicated in many cellular activities, including DNA repair, cell wall homeostasis, osmotic adaptation, biofilm formation, central metabolism, and virulence. c-di-AMP is synthesized and degraded by diadenylate cyclases and phosphodiesterases, respectively. In the diadenylate cyclases, one type of catalytic domain, the diadenylate cyclase (DAC) domain, is coupled to various other domains that control the localization, the protein-protein interactions, and the regulation of the enzymes. The phosphodiesterases have a catalytic core that consists either of a DHH/DHHA1 or of an HD domain. Recent findings on the occurrence, domain organization, activity control, and structural features of diadenylate cyclases and phosphodiesterases are discussed in this review.
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Deng MJ, Tao J, E C, Ye ZY, Jiang Z, Yu J, Su XD. Novel Mechanism for Cyclic Dinucleotide Degradation Revealed by Structural Studies of Vibrio Phosphodiesterase V-cGAP3. J Mol Biol 2018; 430:5080-5093. [PMID: 30365951 DOI: 10.1016/j.jmb.2018.10.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 09/24/2018] [Accepted: 10/17/2018] [Indexed: 12/14/2022]
Abstract
3'3'-cyclic GMP-AMP (3'3'-cGAMP) belongs to a family of the bacterial secondary messenger cyclic dinucleotides. It was first discovered in the Vibrio cholerae seventh pandemic strains and is involved in efficient intestinal colonization and chemotaxis regulation. Phosphodiesterases (PDEs) that degrade 3'3'-cGAMP play important regulatory roles in the relevant signaling pathways, and a previous study has identified three PDEs in V. cholerae, namely, V-cGAP1, V-cGAP2, and V-cGAP3, functioning in 3'3'-cGAMP degradation. We report the crystal structure, biochemical, and structural analyses of V-cGAP3, providing a foundation for understanding the mechanism of 3'3'-cGAMP degradation and regulation in general. Our crystal and molecular dynamic (MD)-simulated structures revealed that V-cGAP3 contains tandem HD-GYP domains within its N- and C-terminal domains, with similar three-dimensional topologies despite their low-sequence identity. Biochemical and structural analyses showed that the N-terminal domain plays a mechanism of positive regulation for the catalytic C-terminal domain. We also demonstrated that the other homologous Vibrio PDEs, V-cGAP1/2, likely function via a similar mechanism.
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Affiliation(s)
- Ming-Jing Deng
- State Key Laboratory of Protein and Plant Gene Research, and Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China
| | - Jianli Tao
- State Key Laboratory of Protein and Plant Gene Research, and Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China; Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Chao E
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Zhao-Yang Ye
- State Key Laboratory of Protein and Plant Gene Research, and Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China; Clinical Research Center, Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou 550004, China
| | - Zhengfan Jiang
- State Key Laboratory of Protein and Plant Gene Research, and Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China; Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Jin Yu
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Xiao-Dong Su
- State Key Laboratory of Protein and Plant Gene Research, and Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing 100871, China.
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63
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Konno H, Yoshida Y, Nagano K, Takebe J, Hasegawa Y. Biological and Biochemical Roles of Two Distinct Cyclic Dimeric Adenosine 3',5'-Monophosphate- Associated Phosphodiesterases in Streptococcus mutans. Front Microbiol 2018; 9:2347. [PMID: 30319597 PMCID: PMC6170606 DOI: 10.3389/fmicb.2018.02347] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 09/12/2018] [Indexed: 12/15/2022] Open
Abstract
Cyclic dimeric adenosine 3′,5′-monophosphate (c-di-AMP), a recently identified secondary messenger in bacteria, plays a role in several bacterial processes, including biofilm formation. It is enzymatically produced by diadenylate cyclase and cleaved by c-di-AMP phosphodiesterase. c-di-AMP is believed to be essential for the viability of bacterial cells that produce it. In the current study, the biochemical and biological roles of GdpP (SMU_2140c) and DhhP (SMU_1297), two distinct Streptococcus mutans phosphodiesterases involved in the pathway producing AMP from c-di-AMP, were investigated. Liquid chromatography-tandem mass spectrometry revealed that c-di-AMP was degraded to phosphoadenylyl adenosine (pApA) by truncated recombinant GdpP, and pApA was cleaved by recombinant DhhP to yield AMP. In-frame deletion mutants lacking the dhhP gene (ΔdhhP) and both the gdpP and dhhP genes (ΔgdpPΔdhhP) displayed significantly more biofilm formation than the wild-type and a mutant strain lacking the gdpP gene (ΔgdpP; p < 0.01). Furthermore, biofilm formation was restored to the level of the wild type strain upon complementation with dhhP. Optical and electron microscopy observations revealed that ΔdhhP and ΔgdpPΔdhhP mutants self-aggregated into large cell clumps, correlated with increased biofilm formation, but cell clumps were not observed in cultures of wild-type, ΔgdpP, or strains complemented with gdpP and dhhP. Thus, deletion of dhhP presumably leads to the formation of bacterial cell aggregates and a subsequent increase in biofilm production.
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Affiliation(s)
- Hiroyasu Konno
- Department of Microbiology, Aichi Gakuin University School of Dentistry, Nagoya, Japan.,Department of Removable Prosthodontics, Aichi Gakuin University School of Dentistry, Nagoya, Japan
| | - Yasuo Yoshida
- Department of Microbiology, Aichi Gakuin University School of Dentistry, Nagoya, Japan
| | - Keiji Nagano
- Department of Microbiology, Aichi Gakuin University School of Dentistry, Nagoya, Japan
| | - Jun Takebe
- Department of Removable Prosthodontics, Aichi Gakuin University School of Dentistry, Nagoya, Japan
| | - Yoshiaki Hasegawa
- Department of Microbiology, Aichi Gakuin University School of Dentistry, Nagoya, Japan
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64
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Zhang Y, Yang J, Bai G. Cyclic di-AMP-mediated interaction between Mycobacterium tuberculosis ΔcnpB and macrophages implicates a novel strategy for improving BCG vaccination. Pathog Dis 2018; 76:4831477. [PMID: 29394352 DOI: 10.1093/femspd/fty008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 01/30/2018] [Indexed: 11/14/2022] Open
Abstract
Cyclic di-AMP (c-di-AMP) has been shown to play an important role in bacterial physiology and pathogen-host interactions. We previously reported that deletion of the sole c-di-AMP phosphodiesterase-encoding gene (cnpB) in Mycobacterium tuberculosis (Mtb) led to significant virulence attenuation. In this study, we found that ΔcnpB of M. bovisbacillus Calmette-Guerin (BCG) was unable to secrete c-di-AMP, which differs from Mtb ΔcnpB. We infected bone marrow-derived macrophages (BMDMs) with c-di-AMP-associated mutants generated from both Mtb and BCG. Our results showed that upon infection with Mtb ΔcnpB, BMDMs of wildtype mice secreted a large amount of interferon-β (IFN-β) post-infection similarly as we reported previously. In contrast, the response was less pronounced with BMDMs isolated from cGAS-/- mice and was nearly abolished with BMDMs prepared from STING-/- mice. Deletion of the region of difference 1 (RD1) locus in Mtb ΔcnpB did not alter the c-di-AMP secretion of ΔcnpB but eliminated the IFN-β production in the infected cells. In contrast, neither BCG ΔcnpB nor a recombinant BCG ΔcnpB with a pRD1 cosmid induced a type I interferon response. Interestingly, multiple studies have demonstrated that type I IFN enhances BCG's immunity. Thus, amending BCG based on our findings might improve BCG vaccination.
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Affiliation(s)
- Yang Zhang
- Department of Immunology and Microbial Disease, MC-151, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208-3479, USA
| | - Jun Yang
- Department of Immunology and Microbial Disease, MC-151, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208-3479, USA
| | - Guangchun Bai
- Department of Immunology and Microbial Disease, MC-151, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208-3479, USA
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65
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Role of DNA Repair and Protective Components in Bacillus subtilis Spore Resistance to Inactivation by 400-nm-Wavelength Blue Light. Appl Environ Microbiol 2018; 84:AEM.01604-18. [PMID: 30054368 DOI: 10.1128/aem.01604-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 07/24/2018] [Indexed: 11/20/2022] Open
Abstract
The high intrinsic decontamination resistance of Firmicutes spores is important medically (disease) and commercially (food spoilage). Effective methods of spore eradication would be of considerable interest in the health care and medical product industries, particularly if the decontamination method effectively killed spores while remaining benign to both humans and sensitive equipment. Intense blue light at a ∼400 nm wavelength is one such treatment that has drawn significant interest. This work has determined the resistance of spores to blue light in an extensive panel of Bacillus subtilis strains, including wild-type strains and mutants that (i) lack protective components such as the spore coat and its pigment(s) or the DNA protective α/β-type small, acid-soluble spore proteins (SASP); (ii) have an elevated spore core water content; or (iii) lack enzymes involved in DNA repair, including those for homologous recombination and nonhomologous end joining (HR and NHEJ), apurinic/apyrimidinic endonucleases, nucleotide and base excision repair (NER and BER), translesion synthesis (TLS) by Y-family DNA polymerases, and spore photoproduct (SP) removal by SP lyase (SPL). The most important factors in spore blue light resistance were determined to be spore coats/pigmentation, α/β-type SASP, NER, BER, TLS, and SP repair. A major conclusion from this work is that blue light kills spores by DNA damage, and the results in this work indicate at least some of the specific DNA damage. It appears that high-intensity blue light could be a significant addition to the agents used to kill bacterial spores in applied settings.IMPORTANCE Effective methods of spore inactivation would be of considerable interest in the health care and medical products industries, particularly if the decontamination method effectively killed spores while remaining benign to both humans and sensitive equipment. Intense blue light radiation is one such treatment that has drawn significant interest. In this work, all known spore-protective features, as well as universal and spore-specific DNA repair mechanisms, were tested in a systematic fashion for their contribution to the resistance of spores to blue light radiation.
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66
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Manikandan K, Prasad D, Srivastava A, Singh N, Dabeer S, Krishnan A, Muniyappa K, Sinha KM. The second messenger cyclic di-AMP negatively regulates the expression of Mycobacterium smegmatis recA and attenuates DNA strand exchange through binding to the C-terminal motif of mycobacterial RecA proteins. Mol Microbiol 2018; 109:600-614. [PMID: 29873124 DOI: 10.1111/mmi.13991] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2018] [Indexed: 12/26/2022]
Abstract
Cyclic di-GMP and cyclic di-AMP are second messengers produced by a wide variety of bacteria. They influence bacterial cell survival, biofilm formation, virulence and bacteria-host interactions. However, many of their cellular targets and biological effects are yet to be determined. A chemical proteomics approach revealed that Mycobacterium smegmatis RecA (MsRecA) possesses a high-affinity cyclic di-AMP binding activity. We further demonstrate that both cyclic di-AMP and cyclic di-GMP bind specifically to the C-terminal motif of MsRecA and Mycobacterium tuberculosis RecA (MtRecA). Escherichia coli RecA (EcRecA) was devoid of cyclic di-AMP binding but have cyclic di-GMP binding activity. Notably, cyclic di-AMP attenuates the DNA strand exchange promoted by MsRecA as well as MtRecA through the disassembly of RecA nucleoprotein filaments. However, the structure and DNA strand exchange activity of EcRecA nucleoprotein filaments remain largely unaffected. Furthermore, M. smegmatis ΔdisA cells were found to have undetectable RecA levels due to the translational repression of recA mRNA. Consequently, the ΔdisA mutant exhibited enhanced sensitivity to DNA-damaging agents. Altogether, this study points out the importance of sequence diversity among recA genes, the role(s) of cyclic di-AMP and reveals a new mode of negative regulation of recA gene expression, DNA repair and homologous recombination in mycobacteria.
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Affiliation(s)
- Kasi Manikandan
- Institute of Molecular Medicine, 254 Okhla Industrial Estate, Phase 3, New Delh, India
| | - Deepika Prasad
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Ankita Srivastava
- Institute of Molecular Medicine, 254 Okhla Industrial Estate, Phase 3, New Delh, India
| | - Nirpendra Singh
- Central Instrument Facility, University of Delhi South Campus, New Delhi, India
| | - Sadaf Dabeer
- Institute of Molecular Medicine, 254 Okhla Industrial Estate, Phase 3, New Delh, India
| | - Anuja Krishnan
- Institute of Molecular Medicine, 254 Okhla Industrial Estate, Phase 3, New Delh, India
| | - K Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Krishna Murari Sinha
- Institute of Molecular Medicine, 254 Okhla Industrial Estate, Phase 3, New Delh, India
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67
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Pham HT, Nhiep NTH, Vu TNM, Huynh TN, Zhu Y, Huynh ALD, Chakrabortti A, Marcellin E, Lo R, Howard CB, Bansal N, Woodward JJ, Liang ZX, Turner MS. Enhanced uptake of potassium or glycine betaine or export of cyclic-di-AMP restores osmoresistance in a high cyclic-di-AMP Lactococcus lactis mutant. PLoS Genet 2018; 14:e1007574. [PMID: 30074984 PMCID: PMC6108528 DOI: 10.1371/journal.pgen.1007574] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/24/2018] [Accepted: 07/20/2018] [Indexed: 11/22/2022] Open
Abstract
The broadly conserved bacterial signalling molecule cyclic-di-adenosine monophosphate (c-di-AMP) controls osmoresistance via its regulation of potassium (K+) and compatible solute uptake. High levels of c-di-AMP resulting from inactivation of c-di-AMP phosphodiesterase activity leads to poor growth of bacteria under high osmotic conditions. To better understand how bacteria can adjust in response to excessive c-di-AMP levels and to identify signals that feed into the c-di-AMP network, we characterised genes identified in a screen for osmoresistant suppressor mutants of the high c-di-AMP Lactococcus ΔgdpP strain. Mutations were identified which increased the uptake of osmoprotectants, including gain-of-function mutations in a Kup family K+ importer (KupB) and inactivation of the glycine betaine transporter transcriptional repressor BusR. The KupB mutations increased the intracellular K+ level while BusR inactivation increased the glycine betaine level. In addition, BusR was found to directly bind c-di-AMP and repress expression of the glycine betaine transporter in response to elevated c-di-AMP. Interestingly, overactive KupB activity or loss of BusR triggered c-di-AMP accumulation, suggesting turgor pressure changes act as a signal for this second messenger. In another group of suppressors, overexpression of an operon encoding an EmrB family multidrug resistance protein allowed cells to lower their intracellular level of c-di-AMP through active export. Lastly evidence is provided that c-di-AMP levels in several bacteria are rapidly responsive to environmental osmolarity changes. Taken together, this work provides evidence for a model in which high c-di-AMP containing cells are dehydrated due to lower K+ and compatible solute levels and that this osmoregulation system is able to sense and respond to cellular water stress.
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Affiliation(s)
- Huong Thi Pham
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
- The University of Danang, University of Science and Technology, Da Nang, Vietnam
| | - Nguyen Thi Hanh Nhiep
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Thu Ngoc Minh Vu
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - TuAnh Ngoc Huynh
- Department of Microbiology, University of Washington, Seattle, WA, United States of America
| | - Yan Zhu
- Monash Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Anh Le Diep Huynh
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | | | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, Queensland, Australia
| | - Raquel Lo
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Christopher B. Howard
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, Queensland, Australia
| | - Nidhi Bansal
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Joshua J. Woodward
- Department of Microbiology, University of Washington, Seattle, WA, United States of America
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Mark S. Turner
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, Queensland, Australia
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68
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Agostoni M, Logan-Jackson AR, Heinz ER, Severin GB, Bruger EL, Waters CM, Montgomery BL. Homeostasis of Second Messenger Cyclic-di-AMP Is Critical for Cyanobacterial Fitness and Acclimation to Abiotic Stress. Front Microbiol 2018; 9:1121. [PMID: 29896182 PMCID: PMC5986932 DOI: 10.3389/fmicb.2018.01121] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/11/2018] [Indexed: 12/11/2022] Open
Abstract
Second messengers are intracellular molecules regulated by external stimuli known as first messengers that are used for rapid organismal responses to dynamic environmental changes. Cyclic di-AMP (c-di-AMP) is a relatively newly discovered second messenger implicated in cell wall homeostasis in many pathogenic bacteria. C-di-AMP is synthesized from ATP by diadenylyl cyclases (DAC) and degraded by specific c-di-AMP phosphodiesterases (PDE). C-di-AMP DACs and PDEs are present in all sequenced cyanobacteria, suggesting roles for c-di-AMP in the physiology and/or development of these organisms. Despite conservation of these genes across numerous cyanobacteria, the functional roles of c-di-AMP in cyanobacteria have not been well-investigated. In a unique feature of cyanobacteria, phylogenetic analysis indicated that the broadly conserved DAC, related to CdaA/DacA, is always co-associated in an operon with genes critical for controlling cell wall synthesis. To investigate phenotypes regulated by c-di-AMP in cyanobacteria, we overexpressed native DAC (sll0505) and c-di-AMP PDE (slr0104) genes in the cyanobacterium Synechocystis sp. PCC 6803 (hereafter Synechocystis) to increase and decrease intracellular c-di-AMP levels, respectively. DAC- and PDE-overexpression strains, showed abnormal aggregation phenotypes, suggesting functional roles for regulating c-di-AMP homeostasis in vivo. As c-di-AMP may be implicated in osmotic responses in cyanobacteria, we tested whether sorbitol and NaCl stresses impacted expression of sll0505 and slr0104 or intracellular c-di-AMP levels in Synechocystis. Additionally, to determine the range of cyanobacteria in which c-di-AMP may function, we assessed c-di-AMP levels in two unicellular cyanobacteria, i.e., Synechocystis and Synechococcus elongatus PCC 7942, and two filamentous cyanobacteria, i.e., Fremyella diplosiphon and Anabaena sp. PCC 7120. C-di-AMP levels responded differently to abiotic stress signals in distinct cyanobacteria strains, whereas salt stress uniformly impacted another second messenger cyclic di-GMP in cyanobacteria. Together, these results suggest regulation of c-di-AMP homeostasis in cyanobacteria and implicate a role for the second messenger in maintaining cellular fitness in response to abiotic stress.
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Affiliation(s)
- Marco Agostoni
- Cell and Molecular Biology Graduate Program, Michigan State University, East Lansing, MI, United States.,Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Alshaé R Logan-Jackson
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, United States.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Emily R Heinz
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Geoffrey B Severin
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Eric L Bruger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Christopher M Waters
- Cell and Molecular Biology Graduate Program, Michigan State University, East Lansing, MI, United States.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Beronda L Montgomery
- Cell and Molecular Biology Graduate Program, Michigan State University, East Lansing, MI, United States.,Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, United States.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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69
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Stress Suppressor Screening Leads to Detection of Regulation of Cyclic di-AMP Homeostasis by a Trk Family Effector Protein in Streptococcus pneumoniae. J Bacteriol 2018; 200:JB.00045-18. [PMID: 29483167 DOI: 10.1128/jb.00045-18] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 02/21/2018] [Indexed: 02/07/2023] Open
Abstract
Cyclic di-AMP (c-di-AMP) is a newly discovered bacterial second messenger. However, regulation of c-di-AMP homeostasis is poorly understood. In Streptococcus pneumoniae, a sole diadenylate cyclase, CdaA, produces c-di-AMP and two phosphodiesterases, Pde1 and Pde2, cleave the signaling dinucleotide. To expand our knowledge of the pneumococcal c-di-AMP signaling network, we performed whole-genome sequencing of Δpde1 Δpde2 heat shock suppressors. In addition to their effects on surviving heat shock, these suppressor mutations restored general stress resistance and improved growth in rich medium. Mutations in CdaA or in the potassium transporter TrkH paired with an insertion leading to a frameshift at the C terminus of CdaA significantly reduced c-di-AMP levels. These observations indicate that the elevated c-di-AMP levels in the Δpde1 Δpde2 mutant enhance susceptibility of S. pneumoniae to the stress conditions. Interestingly, we have previously shown that TrkH complexes with a Trk family c-di-AMP-binding protein, CabP, to mediate potassium uptake. In this study, we found that deletion of cabP significantly reduced pneumococcal c-di-AMP levels. This is the first observation that a c-di-AMP effector protein modulates bacterial c-di-AMP homeostasis.IMPORTANCE Second messengers, including c-di-AMP, are prevalent among bacterial species. In S. pneumoniae, c-di-AMP phosphodiesterase-encoding gene null mutants are attenuated during mouse models of infection, but the role of c-di-AMP signaling in pneumococcal pathogenesis is enigmatic. In this work, we found that heat shock suppressor mutations converge on undermining c-di-AMP toxicity by changing intracellular c-di-AMP concentrations. These mutations improve the growth and restore the stress response generally in c-di-AMP phosphodiesterase-deficient pneumococci, thereby demonstrating the essentiality for tight regulation of c-di-AMP homeostasis in order to respond to stress. Likewise, this work demonstrates that a c-di-AMP effector protein, CabP, affects c-di-AMP homeostasis, which provides new perception into c-di-AMP regulation. This study has implications for c-di-AMP-producing bacteria since many species contain CabP homologs.
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70
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Coping with an Essential Poison: a Genetic Suppressor Analysis Corroborates a Key Function of c-di-AMP in Controlling Potassium Ion Homeostasis in Gram-Positive Bacteria. J Bacteriol 2018; 200:JB.00166-18. [PMID: 29610213 DOI: 10.1128/jb.00166-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cyclic di-AMP (c-di-AMP) is an important second messenger in bacteria. In most Firmicutes, the molecule is required for growth in complex media but also toxic upon accumulation. In an article on their current study, Zarrella and coworkers present a suppressor analysis of a Streptococcus pneumoniae strain that is unable to degrade c-di-AMP (T. M. Zarrella, D. W. Metzger, and G. Bai, J Bacteriol 200:e00045-18, 2018, https://doi.org/10.1128/JB.00045-18). Their study identifies new links between c-di-AMP and potassium homeostasis and supports the hypothesis that c-di-AMP serves as a second messenger to report about the intracellular potassium concentrations.
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71
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Devaux L, Sleiman D, Mazzuoli MV, Gominet M, Lanotte P, Trieu-Cuot P, Kaminski PA, Firon A. Cyclic di-AMP regulation of osmotic homeostasis is essential in Group B Streptococcus. PLoS Genet 2018; 14:e1007342. [PMID: 29659565 PMCID: PMC5919688 DOI: 10.1371/journal.pgen.1007342] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 04/26/2018] [Accepted: 03/28/2018] [Indexed: 02/03/2023] Open
Abstract
Cyclic nucleotides are universally used as secondary messengers to control cellular physiology. Among these signalling molecules, cyclic di-adenosine monophosphate (c-di-AMP) is a specific bacterial second messenger recognized by host cells during infections and its synthesis is assumed to be necessary for bacterial growth by controlling a conserved and essential cellular function. In this study, we sought to identify the main c-di-AMP dependent pathway in Streptococcus agalactiae, the etiological agent of neonatal septicaemia and meningitis. By conditionally inactivating dacA, the only diadenyate cyclase gene, we confirm that c-di-AMP synthesis is essential in standard growth conditions. However, c-di-AMP synthesis becomes rapidly dispensable due to the accumulation of compensatory mutations. We identified several mutations restoring the viability of a ΔdacA mutant, in particular a loss-of-function mutation in the osmoprotectant transporter BusAB. Identification of c-di-AMP binding proteins revealed a conserved set of potassium and osmolyte transporters, as well as the BusR transcriptional factor. We showed that BusR negatively regulates busAB transcription by direct binding to the busAB promoter. Loss of BusR repression leads to a toxic busAB expression in absence of c-di-AMP if osmoprotectants, such as glycine betaine, are present in the medium. In contrast, deletion of the gdpP c-di-AMP phosphodiesterase leads to hyperosmotic susceptibility, a phenotype dependent on a functional BusR. Taken together, we demonstrate that c-di-AMP is essential for osmotic homeostasis and that the predominant mechanism is dependent on the c-di-AMP binding transcriptional factor BusR. The regulation of osmotic homeostasis is likely the conserved and essential function of c-di-AMP, but each species has evolved specific c-di-AMP mechanisms of osmoregulation to adapt to its environment. Nucleotide-based second messengers play central functions in bacterial physiology and host-pathogen interactions. Among these signalling nucleotides, cyclic-di-AMP (c-di-AMP) synthesis was originally assumed to be essential for bacterial growth. In this study, we confirmed that the only di-adenylate cyclase enzyme in the opportunistic pathogen Streptococcus agalactiae is essential in standard growth conditions. However, c-di-AMP synthesis becomes rapidly dispensable by accumulating spontaneous mutations in genes involved in osmotic regulation. We identified that c-di-AMP binds directly to four proteins necessary to maintain osmotic homeostasis, including three osmolyte transporters and the BusR transcriptional factor. We demonstrated that BusR negatively controls the expression of the busAB operon and that it is the main component leading to growth inhibition in the absence of c-di-AMP synthesis if osmoprotectants are present in the environment. Overall, c-di-AMP is essential to maintain osmotic homeostasis by coordinating osmolyte uptake and thus bacteria have developed specific mechanisms to keep c-di-AMP as the central regulator of osmotic homeostasis.
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Affiliation(s)
- Laura Devaux
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Dona Sleiman
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Maria-Vittoria Mazzuoli
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Myriam Gominet
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Philippe Lanotte
- Université de Tours, Infectiologie et Santé Publique, Bactéries et Risque Materno-Fœtal, INRA UMR1282, Tours France
- Hôpital Bretonneau, Centre Hospitalier Régional et Universitaire de Tours, Service de Bactériologie-Virologie, Tours France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Pierre-Alexandre Kaminski
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
| | - Arnaud Firon
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS ERL 6002, Paris, France
- * E-mail:
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72
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Zeden MS, Schuster CF, Bowman L, Zhong Q, Williams HD, Gründling A. Cyclic di-adenosine monophosphate (c-di-AMP) is required for osmotic regulation in Staphylococcus aureus but dispensable for viability in anaerobic conditions. J Biol Chem 2018; 293:3180-3200. [PMID: 29326168 PMCID: PMC5836111 DOI: 10.1074/jbc.m117.818716] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/03/2018] [Indexed: 01/15/2023] Open
Abstract
Cyclic di-adenosine monophosphate (c-di-AMP) is a recently discovered signaling molecule important for the survival of Firmicutes, a large bacterial group that includes notable pathogens such as Staphylococcus aureus However, the exact role of this molecule has not been identified. dacA, the S. aureus gene encoding the diadenylate cyclase enzyme required for c-di-AMP production, cannot be deleted when bacterial cells are grown in rich medium, indicating that c-di-AMP is required for growth in this condition. Here, we report that an S. aureus dacA mutant can be generated in chemically defined medium. Consistent with previous findings, this mutant had a severe growth defect when cultured in rich medium. Using this growth defect in rich medium, we selected for suppressor strains with improved growth to identify c-di-AMP-requiring pathways. Mutations bypassing the essentiality of dacA were identified in alsT and opuD, encoding a predicted amino acid and osmolyte transporter, the latter of which we show here to be the main glycine betaine-uptake system in S. aureus. Inactivation of these transporters likely prevents the excessive osmolyte and amino acid accumulation in the cell, providing further evidence for a key role of c-di-AMP in osmotic regulation. Suppressor mutations were also obtained in hepS, hemB, ctaA, and qoxB, coding proteins required for respiration. Furthermore, we show that dacA is dispensable for growth in anaerobic conditions. Together, these findings reveal an essential role for the c-di-AMP signaling network in aerobic, but not anaerobic, respiration in S. aureus.
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Affiliation(s)
- Merve S Zeden
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Christopher F Schuster
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Lisa Bowman
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Qiyun Zhong
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
| | - Huw D Williams
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Angelika Gründling
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection and
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73
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Wang J, Lu SF, Wan B, Ming SL, Li GL, Su BQ, Liu JY, Wei YS, Yang GY, Chu BB. Maintenance of cyclic GMP-AMP homeostasis by ENPP1 is involved in pseudorabies virus infection. Mol Immunol 2018; 95:56-63. [PMID: 29407577 DOI: 10.1016/j.molimm.2018.01.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/04/2017] [Accepted: 01/19/2018] [Indexed: 12/17/2022]
Abstract
In a previous study, we demonstrated that porcine cyclic GMP-AMP (cGAMP) synthase (cGAS) catalyzes cGAMP production and is an important DNA sensor for the pseudorabies virus (PRV)-induced activation of interferon β (IFN-β). Ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) has recently been identified as the hydrolase of cGAMP in rodents, but its role in porcine cells is not clear. Our recent study demonstrated that porcine ENPP1 is responsible for the homeostasis of cGAMP and is critical for PRV infection. Porcine ENPP1 mRNA is predominantly expressed in muscle. PRV infection was enhanced by ENPP1 overexpression and attenuated by silencing of ENPP1. During PRV infection, the activation of IFN-β and NF-κB was reduced in ENPP1 overexpressed cells and promoted in ENPP1 knockdown cells. Investigation of the molecular mechanisms of ENPP1 during PRV infection showed that ENPP1 hydrolyzed cGAMP in PRV-infected or cGAMP-transfected cells and inhibited IRF3 phosphorylation, reducing IFN-β secretion. These results, combined with those for porcine cGAS, demonstrate that ENPP1 acts coordinately with cGAS to maintain the reservoir of cGAMP and participates in PRV infection.
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Affiliation(s)
- Jiang Wang
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Shao-Fang Lu
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Bo Wan
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Sheng-Li Ming
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Guo-Li Li
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Bing-Qian Su
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Jiao-Yang Liu
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Yu-Shuang Wei
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China
| | - Guo-Yu Yang
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China.
| | - Bei-Bei Chu
- College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, PR China.
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74
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Structural and biochemical characterization of the catalytic domains of GdpP reveals a unified hydrolysis mechanism for the DHH/DHHA1 phosphodiesterase. Biochem J 2018; 475:191-205. [PMID: 29203646 DOI: 10.1042/bcj20170739] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 12/22/2022]
Abstract
The Asp-His-His and Asp-His-His-associated (DHH/DHHA1) domain-containing phosphodiesterases (PDEs) that catalyze degradation of cyclic di-adenosine monophosphate (c-di-AMP) could be subdivided into two subfamilies based on the final product [5'-phosphadenylyl-adenosine (5'-pApA) or AMP]. In a previous study, we revealed that Rv2837c, a stand-alone DHH/DHHA1 PDE, employs a 5'-pApA internal flipping mechanism to produce AMPs. However, why the membrane-bound DHH/DHHA1 PDE can only degrade c-di-AMP to 5'-pApA remains obscure. Here, we report the crystal structure of the DHH/DHHA1 domain of GdpP (GdpP-C), and structures in complex with c-di-AMP, cyclic di-guanosine monophosphate (c-di-GMP), and 5'-pApA. Structural analysis reveals that GdpP-C binds nucleotide substrates quite differently from how Rv2837c does in terms of substrate-binding position. Accordingly, the nucleotide-binding site of the DHH/DHHA1 PDEs is organized into three (C, G, and R) subsites. For GdpP-C, in the C and G sites c-di-AMP binds and degrades into 5'-pApA, and its G site determines nucleotide specificity. To further degrade into AMPs, 5'-pApA must slide into the C and R sites for flipping and hydrolysis as in Rv2837c. Subsequent mutagenesis and enzymatic studies of GdpP-C and Rv2837c uncover the complete flipping process and reveal a unified catalytic mechanism for members of both DHH/DHHA1 PDE subfamilies.
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75
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Devaux L, Kaminski PA, Trieu-Cuot P, Firon A. Cyclic di-AMP in host-pathogen interactions. Curr Opin Microbiol 2017; 41:21-28. [PMID: 29169058 DOI: 10.1016/j.mib.2017.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/24/2017] [Accepted: 11/04/2017] [Indexed: 01/09/2023]
Abstract
Cyclic di-AMP (c-di-AMP) is a bacterial signaling nucleotide synthesized by several human pathogens. This widespread and specific bacterial product is recognized by infected host cells to trigger an innate immune response. Detection of c-di-AMP in the host cytosol leads primarily to the induction of type I interferon via the STING-cGAS signaling axis, while being also entangled in the activation of the NF-κB pathway. During their long-standing interaction, host and pathogens have co-evolved to control c-di-AMP activation of innate immunity. On the bacterial side, the quantity of c-di-AMP released inside cells allows to manipulate the host response to exacerbate infection by avoiding immune recognition or, at the opposite, by overloading the STING-cGAS pathway.
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Affiliation(s)
- Laura Devaux
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS URL3526, Paris, France; Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Pierre-Alexandre Kaminski
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS URL3526, Paris, France
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS URL3526, Paris, France
| | - Arnaud Firon
- Institut Pasteur, Unité Biologie des Bactéries Pathogènes à Gram-positif, CNRS URL3526, Paris, France.
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76
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Abstract
Non-coding regulatory RNAs fine-tune gene expression post-transcriptionally. In the streptomycetes, rpfA - encoding a muralytic enzyme required for establishing and exiting dormancy - is flanked by non-coding regulatory RNA elements both upstream (riboswitch) and downstream [antisense small RNA (sRNA)]. In Streptomyces coelicolor, the upstream riboswitch decreases rpfA transcript abundance in response to the second messenger cyclic di-AMP, itself involved in cell wall metabolism and dormancy. There is, however, no obvious expression platform associated with this riboswitch and consequently, its mechanism of action is entirely unknown. Using in vitro transcription assays, we discovered that the rpfA riboswitch promoted premature transcription termination in response to cyclic di-AMP. Through an extensive mutational analysis, we determined that attenuation required ligand binding and involved an unusual extended stem-loop region unique to a subset of rpfA riboswitches in the actinobacteria. At the other end of the rpfA gene, an antisense sRNA, termed Scr3097, is expressed opposite the predicted rpfA terminator. Using northern blotting, we found that Scr3097 accumulation mirrored that of the rpfA mRNA. In liquid culture, we detected Scr3097 exclusively in exponential-phase cells, and in plate-grown culture, we observed the sRNA primarily in differentiating cultures. Using mutational analyses, we found that the sRNA increased rpfA mRNA abundance in cells. Taken together, our work revealed multiple regulatory RNAs controlling rpfA expression in the streptomycetes.
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Affiliation(s)
- Renée J St-Onge
- a Department of Biology and Michael G. DeGroote Institute for Infectious Disease Research , McMaster University , Hamilton , Ontario , Canada
| | - Marie A Elliot
- a Department of Biology and Michael G. DeGroote Institute for Infectious Disease Research , McMaster University , Hamilton , Ontario , Canada
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77
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Drexler DJ, Müller M, Rojas-Cordova CA, Bandera AM, Witte G. Structural and Biophysical Analysis of the Soluble DHH/DHHA1-Type Phosphodiesterase TM1595 from Thermotoga maritima. Structure 2017; 25:1887-1897.e4. [PMID: 29107484 DOI: 10.1016/j.str.2017.10.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/07/2017] [Accepted: 09/29/2017] [Indexed: 11/26/2022]
Abstract
The concentration of messenger molecules in bacterial cells needs to be tightly regulated. This can be achieved by either controlling the synthesis rate, degradation, or export by specific transporters, respectively. The regulation of the essential second messenger c-di-AMP is achieved by modulation of the diadenylate cyclase activity as well as by specific phosphodiesterases that hydrolyze c-di-AMP in the cell. We provide here structural and biochemical data on the DHH-type phosphodiesterase TmPDE (TM1595) from Thermotoga maritima. Our analysis shows that TmPDE is preferentially degrading linear dinucleotides, such as 5'-pApA, 5'-pGpG, and 5'-pApG, compared with cyclic dinucleotide substrates. The high-resolution structural data provided here describe all steps of the PDE reaction: the ligand-free enzyme, two substrate-bound states, and three post-reaction states. We can furthermore show that Pde2 from Streptococcus pneumoniae shares both structural features and substrate specificity based on small-angle X-ray scattering data and biochemical assays.
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Affiliation(s)
- David Jan Drexler
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Martina Müller
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Carlos Alberto Rojas-Cordova
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Adrian Maurice Bandera
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
| | - Gregor Witte
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany.
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78
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A Delicate Connection: c-di-AMP Affects Cell Integrity by Controlling Osmolyte Transport. Trends Microbiol 2017; 26:175-185. [PMID: 28965724 DOI: 10.1016/j.tim.2017.09.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/16/2017] [Accepted: 09/08/2017] [Indexed: 12/15/2022]
Abstract
Bacteria use second-messenger molecules to adapt to their environment. Several second messengers, among them cyclic di-AMP (c-di-AMP), have been discovered and intensively studied. Interestingly, c-di-AMP is essential for growth of Gram-positive bacteria such as Bacillus subtilis, Listeria monocytogenes, and Staphylococcus aureus. Many studies demonstrated that perturbation of c-di-AMP metabolism affects the integrity of the bacterial cell envelope. Therefore, it has been assumed that the nucleotide is essential for proper cell envelope synthesis. In this Opinion paper, we propose that the cell envelope phenotypes caused by perturbations of c-di-AMP metabolism can be interpreted differently: c-di-AMP might indirectly control cell envelope integrity by modulating the turgor, a physical variable that needs to be tightly adjusted. We also discuss open questions related to c-di-AMP metabolism that need to be urgently addressed by future studies.
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79
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Gundlach J, Commichau FM, Stülke J. Perspective of ions and messengers: an intricate link between potassium, glutamate, and cyclic di-AMP. Curr Genet 2017; 64:191-195. [PMID: 28825218 DOI: 10.1007/s00294-017-0734-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 08/09/2017] [Accepted: 08/10/2017] [Indexed: 01/15/2023]
Abstract
Potassium and glutamate are the most abundant ions in every living cell. Whereas potassium plays a major role to keep the cellular turgor and to buffer the negative charges of the nucleic acids, the major function of glutamate is to serve as the universal amino group donor. In addition, both ions are involved in osmoprotection in bacterial cells. Here, we discuss how bacterial cells maintain the homeostasis of both ions and how adaptive evolution allows them to live even at extreme potassium limitation. Interestingly, positively charged amino acids are able to partially replace potassium, likely by buffering the negative charge of DNA. A major factor involved in the control of potassium homeostasis in Gram-positive bacteria is the essential second messenger cyclic di-AMP. This nucleotide is synthesized in response to the potassium concentration and in turn controls the expression and activity of potassium transporters. We discuss the link between the two major ions, DNA and the second messenger c-di-AMP.
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Affiliation(s)
- Jan Gundlach
- Department of General Microbiology, Georg-August-University Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Fabian M Commichau
- Department of General Microbiology, Georg-August-University Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, Georg-August-University Göttingen, Grisebachstr. 8, 37077, Göttingen, Germany.
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80
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Bacterial Signaling Nucleotides Inhibit Yeast Cell Growth by Impacting Mitochondrial and Other Specifically Eukaryotic Functions. mBio 2017; 8:mBio.01047-17. [PMID: 28743817 PMCID: PMC5527313 DOI: 10.1128/mbio.01047-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We have engineered Saccharomyces cerevisiae to inducibly synthesize the prokaryotic signaling nucleotides cyclic di-GMP (cdiGMP), cdiAMP, and ppGpp in order to characterize the range of effects these nucleotides exert on eukaryotic cell function during bacterial pathogenesis. Synthetic genetic array (SGA) and transcriptome analyses indicated that, while these compounds elicit some common reactions in yeast, there are also complex and distinctive responses to each of the three nucleotides. All three are capable of inhibiting eukaryotic cell growth, with the guanine nucleotides exhibiting stronger effects than cdiAMP. Mutations compromising mitochondrial function and chromatin remodeling show negative epistatic interactions with all three nucleotides. In contrast, certain mutations that cause defects in chromatin modification and ribosomal protein function show positive epistasis, alleviating growth inhibition by at least two of the three nucleotides. Uniquely, cdiGMP is lethal both to cells growing by respiration on acetate and to obligately fermentative petite mutants. cdiGMP is also synthetically lethal with the ribonucleotide reductase (RNR) inhibitor hydroxyurea. Heterologous expression of the human ppGpp hydrolase Mesh1p prevented the accumulation of ppGpp in the engineered yeast and restored cell growth. Extensive in vivo interactions between bacterial signaling molecules and eukaryotic gene function occur, resulting in outcomes ranging from growth inhibition to death. cdiGMP functions through a mechanism that must be compensated by unhindered RNR activity or by functionally competent mitochondria. Mesh1p may be required for abrogating the damaging effects of ppGpp in human cells subjected to bacterial infection.IMPORTANCE During infections, pathogenic bacteria can release nucleotides into the cells of their eukaryotic hosts. These nucleotides are recognized as signals that contribute to the initiation of defensive immune responses that help the infected cells recover. Despite the importance of this process, the broader impact of bacterial nucleotides on the functioning of eukaryotic cells remains poorly defined. To address this, we genetically modified cells of the eukaryote Saccharomyces cerevisiae (baker's yeast) to produce three of these molecules (cdiAMP, cdiGMP, and ppGpp) and used the engineered strains as model systems to characterize the effects of the molecules on the cells. In addition to demonstrating that the nucleotides are each capable of adversely affecting yeast cell function and growth, we also identified the cellular functions important for mitigating the damage caused, suggesting possible modes of action. This study expands our understanding of the molecular interactions that can take place between bacterial and eukaryotic cells.
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81
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Blötz C, Treffon K, Kaever V, Schwede F, Hammer E, Stülke J. Identification of the Components Involved in Cyclic Di-AMP Signaling in Mycoplasma pneumoniae. Front Microbiol 2017; 8:1328. [PMID: 28751888 PMCID: PMC5508000 DOI: 10.3389/fmicb.2017.01328] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/30/2017] [Indexed: 11/13/2022] Open
Abstract
Bacteria often use cyclic dinucleotides as second messengers for signal transduction. While the classical molecule c-di-GMP is involved in lifestyle selection, the functions of the more recently discovered signaling nucleotide cyclic di-AMP are less defined. For many Gram-positive bacteria, c-di-AMP is essential for growth suggesting its involvement in a key cellular function. We have analyzed c-di-AMP signaling in the genome-reduced pathogenic bacterium Mycoplasma pneumoniae. Our results demonstrate that these bacteria produce c-di-AMP, and we could identify the diadenylate cyclase CdaM (MPN244). This enzyme is the founding member of a novel family of diadenylate cyclases. Of two potential c-di-AMP degrading phosphodiesterases, only PdeM (MPN549) is active in c-di-AMP degradation, whereas NrnA (MPN140) was reported to degrade short oligoribonucleotides. As observed in other bacteria, both the c-di-AMP synthesizing and the degrading enzymes are essential for M. pneumoniae suggesting control of a major homeostatic process. To obtain more insights into the nature of this process, we have identified a c-di-AMP-binding protein from M. pneumoniae, KtrC. KtrC is the cytoplasmic regulatory subunit of the low affinity potassium transporter KtrCD. It is established that binding of c-di-AMP inhibits the KtrCD activity resulting in a limitation of potassium uptake. Our results suggest that the control of potassium homeostasis is the essential function of c-di-AMP in M. pneumoniae.
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Affiliation(s)
- Cedric Blötz
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University GöttingenGöttingen, Germany
| | - Katrin Treffon
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University GöttingenGöttingen, Germany
| | - Volkhard Kaever
- Research Core Unit Metabolomics, Hannover Medical SchoolHannover, Germany
| | | | - Elke Hammer
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine GreifswaldGreifswald, Germany
| | - Jörg Stülke
- Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University GöttingenGöttingen, Germany
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82
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Abstract
Potassium is the most abundant metal ion in every living cell. This ion is essential due to its requirement for the activity of the ribosome and many enzymes but also because of its role in buffering the negative charge of nucleic acids. As the external concentrations of potassium are usually low, efficient uptake and intracellular enrichment of the ion is necessary. The Gram-positive bacterium Bacillus subtilis possesses three transporters for potassium, KtrAB, KtrCD, and the recently discovered KimA. In the absence of the high-affinity transporters KtrAB and KimA, the bacteria were unable to grow at low potassium concentrations. However, we observed the appearance of suppressor mutants that were able to overcome the potassium limitation. All these suppressor mutations affected amino acid metabolism, particularly arginine biosynthesis. In the mutants, the intracellular levels of ornithine, citrulline, and arginine were strongly increased, suggesting that these amino acids can partially substitute for potassium. This was confirmed by the observation that the supplementation with positively charged amino acids allows growth of B. subtilis even at the extreme potassium limitation that the bacteria experience if no potassium is added to the medium. In addition, a second class of suppressor mutations allowed growth at extreme potassium limitation. These mutations result in increased expression of KtrAB, the potassium transporter with the highest affinity and therefore allow the acquisition and accumulation of the smallest amounts of potassium ions from the environment. Potassium is essential for every living cell as it is required for the activity for many enzymes and for maintaining the intracellular pH by buffering the negative charge of the nucleic acids. We have studied the adaptation of the soil bacterium Bacillus subtilis to life at low potassium concentrations. If the major high-affinity transporters are missing, the bacteria are unable to grow unless they acquire mutations that result in the accumulation of positively charged amino acids such as ornithine, citrulline, and arginine. Supplementation of the medium with these amino acids rescued growth even in the absence of externally added potassium. Moreover, these growth conditions, which the bacteria experience as an extreme potassium limitation, can be overcome by the acquisition of mutations that result in increased expression of the high-affinity potassium transporter KtrAB. Our results indicate that positively charged amino acids can partially take over the function of potassium.
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83
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LC-MS/MS proteomic analysis of starved Bacillus subtilis cells overexpressing ribonucleotide reductase (nrdEF): implications in stress-associated mutagenesis. Curr Genet 2017. [PMID: 28624879 DOI: 10.1007/s00294-017-0722-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The non-appropriate conditions faced by nutritionally stressed bacteria propitiate error-prone repair events underlying stationary-phase- or stress-associated mutagenesis (SPM). The genetic and molecular mechanisms involved in SPM have been deeply studied but the biochemical aspects of this process have so far been less explored. Previous evidence showed that under conditions of nutritional stress, non-dividing cells of strain B. subtilis YB955 overexpressing ribonucleotide reductase (RNR) exhibited a strong propensity to generate true reversions in the hisC952 (amber), metB5 (ochre) and leuC425 (missense) mutant alleles. To further advance our knowledge on the metabolic conditions underlying this hypermutagenic phenotype, a high-throughput LC-MS/MS proteomic analysis was performed in non-dividing cells of an amino acid-starved strain, deficient for NrdR, the RNR repressor. Compared with the parental strain, the level of 57 proteins was found to increase and of 80 decreases in the NrdR-deficient strain. The proteomic analysis revealed an altered content in proteins associated with the stringent response, nucleotide metabolism, DNA repair, and cell signaling in amino acid-starved cells of the ∆nrdR strain. Overall, our results revealed that amino acid-starved cells of strain B. subtilis ∆nrdR that escape from growth-limiting conditions exhibit a complex proteomic pattern reminiscent of a disturbed metabolism. Future experiments aimed to understand the consequences of disrupting the cell signaling pathways unveiled in this study, will advance our knowledge on the genetic adaptations deployed by bacteria to escape from growth-limiting environments.
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84
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Krasteva PV, Sondermann H. Versatile modes of cellular regulation via cyclic dinucleotides. Nat Chem Biol 2017; 13:350-359. [PMID: 28328921 DOI: 10.1038/nchembio.2337] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 01/17/2017] [Indexed: 02/06/2023]
Abstract
Since the discovery of c-di-GMP almost three decades ago, cyclic dinucleotides (CDNs) have emerged as widely used signaling molecules in most kingdoms of life. The family of second messengers now includes c-di-AMP and distinct versions of mixed cyclic GMP-AMP (cGAMP) compounds. In addition to these nucleotides, a vast number of proteins for the production and turnover of these molecules have been described, as well as effectors that translate the signals into physiological responses. The latter include, but are not limited to, mechanisms for adaptation and survival in prokaryotes, persistence and virulence of bacterial pathogens, and immune responses to viral and bacterial invasion in eukaryotes. In this review, we will focus on recent discoveries and emerging themes that illustrate the ubiquity and versatility of cyclic dinucleotide function at the transcriptional and post-translational levels and, in particular, on insights gained through mechanistic structure-function analyses.
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Affiliation(s)
- Petya Violinova Krasteva
- Unité G5 Biologie Structurale de la Sécrétion Bactérienne, UMR 3528 - CNRS, Institut Pasteur, Paris, France.,Structural Biology of Biofilms Group, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, Gif sur Yvette, France
| | - Holger Sondermann
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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85
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Gundlach J, Herzberg C, Kaever V, Gunka K, Hoffmann T, Weiß M, Gibhardt J, Thürmer A, Hertel D, Daniel R, Bremer E, Commichau FM, Stülke J. Control of potassium homeostasis is an essential function of the second messenger cyclic di-AMP in Bacillus subtilis. Sci Signal 2017; 10:10/475/eaal3011. [PMID: 28420751 DOI: 10.1126/scisignal.aal3011] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The second messenger cyclic di-adenosine monophosphate (c-di-AMP) is essential in the Gram-positive model organism Bacillus subtilis and in related pathogenic bacteria. It controls the activity of the conserved ydaO riboswitch and of several proteins involved in potassium (K+) uptake. We found that the YdaO protein was conserved among several different bacteria and provide evidence that YdaO functions as a K+ transporter. Thus, we renamed the gene and protein KimA (K+ importer A). Reporter activity assays indicated that expression beyond the c-di-AMP-responsive riboswitch of the kimA upstream regulatory region occurred only in bacteria grown in medium containing low K+ concentrations. Furthermore, mass spectrometry analysis indicated that c-di-AMP accumulated in bacteria grown in the presence of high K+ concentrations but not in low concentrations. A bacterial strain lacking all genes encoding c-di-AMP-synthesizing enzymes was viable when grown in medium containing low K+ concentrations, but not at higher K+ concentrations unless it acquired suppressor mutations in the gene encoding the cation exporter NhaK. Thus, our results indicated that the control of potassium homeostasis is an essential function of c-di-AMP.
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Affiliation(s)
- Jan Gundlach
- Department of General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Christina Herzberg
- Department of General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Volkhard Kaever
- Research Core Unit Metabolomics, Hannover Medical School, 30625 Hannover, Germany
| | - Katrin Gunka
- Department of General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Tamara Hoffmann
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, 35043 Marburg, Germany
| | - Martin Weiß
- Department of General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Johannes Gibhardt
- Department of General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Andrea Thürmer
- Department of Genomic and Applied Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Dietrich Hertel
- Department of Plant Ecology and Ecosystems Research, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Erhard Bremer
- Department of Biology, Laboratory for Microbiology, Philipps-University Marburg, 35043 Marburg, Germany.,LOEWE Center for Synthetic Microbiology, Philipps-University Marburg, 35043 Marburg, Germany
| | - Fabian M Commichau
- Department of General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany. .,Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University Göttingen, 37077 Göttingen, Germany
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86
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A Novel Phosphodiesterase of the GdpP Family Modulates Cyclic di-AMP Levels in Response to Cell Membrane Stress in Daptomycin-Resistant Enterococci. Antimicrob Agents Chemother 2017; 61:AAC.01422-16. [PMID: 28069645 DOI: 10.1128/aac.01422-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 12/26/2016] [Indexed: 12/20/2022] Open
Abstract
Substitutions in the LiaFSR membrane stress pathway are frequently associated with the emergence of antimicrobial peptide resistance in both Enterococcus faecalis and Enterococcus faecium Cyclic di-AMP (c-di-AMP) is an important signal molecule that affects many aspects of bacterial physiology, including stress responses. We have previously identified a mutation in a gene (designated yybT) in E. faecalis that was associated with the development of daptomycin resistance, resulting in a change at position 440 (yybTI440S) in the predicted protein. Here, we show that intracellular c-di-AMP signaling is present in enterococci, and on the basis of in vitro physicochemical characterization, we show that E. faecalisyybT encodes a cyclic dinucleotide phosphodiesterase of the GdpP family that exhibits specific activity toward c-di-AMP by hydrolyzing it to 5'pApA. The E. faecalis GdpPI440S substitution reduces c-di-AMP phosphodiesterase activity more than 11-fold, leading to further increases in c-di-AMP levels. Additionally, deletions of liaR (encoding the response regulator of the LiaFSR system) that lead to daptomycin hypersusceptibility in both E. faecalis and E. faecium also resulted in increased c-di-AMP levels, suggesting that changes in the LiaFSR stress response pathway are linked to broader physiological changes. Taken together, our data show that modulation of c-di-AMP pools is strongly associated with antibiotic-induced cell membrane stress responses via changes in GdpP activity or signaling through the LiaFSR system.
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87
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Abstract
Cyclic dinucleotides (CDNs) are highly versatile signalling molecules that control various important biological processes in bacteria. The best-studied example is cyclic di-GMP (c-di-GMP). Known since the late 1980s, it is now recognized as a near-ubiquitous second messenger that coordinates diverse aspects of bacterial growth and behaviour, including motility, virulence, biofilm formation and cell cycle progression. In this Review, we discuss important new insights that have been gained into the molecular principles of c-di-GMP synthesis and degradation, which are mediated by diguanylate cyclases and c-di-GMP-specific phosphodiesterases, respectively, and the cellular functions that are exerted by c-di-GMP-binding effectors and their diverse targets. Finally, we provide a short overview of the signalling versatility of other CDNs, including c-di-AMP and cGMP-AMP (cGAMP).
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88
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Cyclic di-AMP Released from Staphylococcus aureus Biofilm Induces a Macrophage Type I Interferon Response. Infect Immun 2016; 84:3564-3574. [PMID: 27736778 PMCID: PMC5116733 DOI: 10.1128/iai.00447-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 10/01/2016] [Indexed: 12/14/2022] Open
Abstract
Staphylococcus aureus is a leading cause of community- and nosocomial-acquired infections, with a propensity for biofilm formation. S. aureus biofilms actively skew the host immune response toward an anti-inflammatory state; however, the biofilm effector molecules and the mechanism(s) of action responsible for this phenomenon remain to be fully defined. The essential bacterial second messenger cyclic diadenylate monophosphate (c-di-AMP) is an emerging pathogen-associated molecular pattern during intracellular bacterial infections, as c-di-AMP secretion into the infected host cytosol induces a robust type I interferon (IFN) response. Type I IFNs have the potential to exacerbate infectious outcomes by promoting anti-inflammatory effects; however, the type I IFN response to S. aureus biofilms is unknown. Additionally, while several intracellular proteins function as c-di-AMP receptors in S. aureus, it has yet to be determined if any extracellular role for c-di-AMP exists and its release during biofilm formation has not yet been demonstrated. This study examined the possibility that c-di-AMP released during S. aureus biofilm growth polarizes macrophages toward an anti-inflammatory phenotype via type I interferon signaling. DacA, the enzyme responsible for c-di-AMP synthesis in S. aureus, was highly expressed during biofilm growth, and 30 to 50% of total c-di-AMP produced from S. aureus biofilm was released extracellularly due to autolytic activity. S. aureus biofilm c-di-AMP release induced macrophage type I IFN expression via a STING-dependent pathway and promoted S. aureus intracellular survival in macrophages. These findings identify c-di-AMP as another mechanism for how S. aureus biofilms promote macrophage anti-inflammatory activity, which likely contributes to biofilm persistence.
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89
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Bowman L, Zeden MS, Schuster CF, Kaever V, Gründling A. New Insights into the Cyclic Di-adenosine Monophosphate (c-di-AMP) Degradation Pathway and the Requirement of the Cyclic Dinucleotide for Acid Stress Resistance in Staphylococcus aureus. J Biol Chem 2016; 291:26970-26986. [PMID: 27834680 PMCID: PMC5207132 DOI: 10.1074/jbc.m116.747709] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 11/09/2016] [Indexed: 12/02/2022] Open
Abstract
Nucleotide signaling networks are key to facilitate alterations in gene expression, protein function, and enzyme activity in response to diverse stimuli. Cyclic di-adenosine monophosphate (c-di-AMP) is an important secondary messenger molecule produced by the human pathogen Staphylococcus aureus and is involved in regulating a number of physiological processes including potassium transport. S. aureus must ensure tight control over its cellular levels as both high levels of the dinucleotide and its absence result in a number of detrimental phenotypes. Here we show that in addition to the membrane-bound Asp-His-His and Asp-His-His-associated (DHH/DHHA1) domain-containing phosphodiesterase (PDE) GdpP, S. aureus produces a second cytoplasmic DHH/DHHA1 PDE Pde2. Although capable of hydrolyzing c-di-AMP, Pde2 preferentially converts linear 5′-phosphadenylyl-adenosine (pApA) to AMP. Using a pde2 mutant strain, pApA was detected for the first time in S. aureus, leading us to speculate that this dinucleotide may have a regulatory role under certain conditions. Moreover, pApA is involved in a feedback inhibition loop that limits GdpP-dependent c-di-AMP hydrolysis. Another protein linked to the regulation of c-di-AMP levels in bacteria is the predicted regulator protein YbbR. Here, it is shown that a ybbR mutant S. aureus strain has increased acid sensitivity that can be bypassed by the acquisition of mutations in a number of genes, including the gene coding for the diadenylate cyclase DacA. We further show that c-di-AMP levels are slightly elevated in the ybbR suppressor strains tested as compared with the wild-type strain. With this, we not only identified a new role for YbbR in acid stress resistance in S. aureus but also provide further insight into how c-di-AMP levels impact acid tolerance in this organism.
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Affiliation(s)
- Lisa Bowman
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom and
| | - Merve S Zeden
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom and
| | - Christopher F Schuster
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom and
| | - Volkhard Kaever
- the Research Core Unit Metabolomics, Hannover Medical School, Hannover D-306625, Germany
| | - Angelika Gründling
- From the Section of Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom and
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90
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Pham TH, Liang ZX, Marcellin E, Turner MS. Replenishing the cyclic-di-AMP pool: regulation of diadenylate cyclase activity in bacteria. Curr Genet 2016; 62:731-738. [PMID: 27074767 DOI: 10.1007/s00294-016-0600-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 03/29/2016] [Accepted: 04/01/2016] [Indexed: 02/08/2023]
Abstract
Bacteria can sense environmental cues and alter their physiology accordingly through the use of signal transduction pathways involving second messenger nucleotides. One broadly conserved second messenger is cyclic-di-AMP (c-di-AMP) which regulates a range of processes including cell wall homeostasis, potassium uptake, DNA repair, fatty acid synthesis, biofilm formation and central metabolism in bacteria. The intracellular pool of c-di-AMP is maintained by the activities of diadenylate cyclase (DAC) and phosphodiesterase (PDE) enzymes, as well as possibly via c-di-AMP export. Whilst extracellular stimuli regulating c-di-AMP levels in bacteria are poorly understood, recent work has identified effector proteins which directly interact and alter the activity of DACs. These include the membrane bound CdaR and the phosphoglucosamine mutase GlmM which both bind directly to the membrane bound CdaA DAC and the recombination protein RadA which binds directly to the DNA binding DisA DAC. The genes encoding these multiprotein complexes are co-localised in many bacteria providing further support for their functional connection. The roles of GlmM in peptidoglycan synthesis and RadA in Holliday junction intermediate processing suggest that c-di-AMP synthesis by DACs will be responsive to these cellular activities. In addition to these modulatory interactions, permanent dysregulation of DAC activity due to suppressor mutations can occur during selection to overcome growth defects, rapid cell lysis and osmosensitivity. DACs have also been investigated as targets for the development of new antibiotics and several small compound inhibitors have recently been identified. This review aims to provide an overview of how c-di-AMP synthesis by DACs can be regulated.
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Affiliation(s)
- Thi Huong Pham
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD, Australia
| | - Mark S Turner
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, Australia.
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD, Australia.
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91
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Regulatory RNAs in Bacillus subtilis: a Gram-Positive Perspective on Bacterial RNA-Mediated Regulation of Gene Expression. Microbiol Mol Biol Rev 2016; 80:1029-1057. [PMID: 27784798 DOI: 10.1128/mmbr.00026-16] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria can employ widely diverse RNA molecules to regulate their gene expression. Such molecules include trans-acting small regulatory RNAs, antisense RNAs, and a variety of transcriptional attenuation mechanisms in the 5' untranslated region. Thus far, most regulatory RNA research has focused on Gram-negative bacteria, such as Escherichia coli and Salmonella. Hence, there is uncertainty about whether the resulting insights can be extrapolated directly to other bacteria, such as the Gram-positive soil bacterium Bacillus subtilis. A recent study identified 1,583 putative regulatory RNAs in B. subtilis, whose expression was assessed across 104 conditions. Here, we review the current understanding of RNA-based regulation in B. subtilis, and we categorize the newly identified putative regulatory RNAs on the basis of their conservation in other bacilli and the stability of their predicted secondary structures. Our present evaluation of the publicly available data indicates that RNA-mediated gene regulation in B. subtilis mostly involves elements at the 5' ends of mRNA molecules. These can include 5' secondary structure elements and metabolite-, tRNA-, or protein-binding sites. Importantly, sense-independent segments are identified as the most conserved and structured potential regulatory RNAs in B. subtilis. Altogether, the present survey provides many leads for the identification of new regulatory RNA functions in B. subtilis.
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92
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Eijlander RT, Holsappel S, de Jong A, Ghosh A, Christie G, Kuipers OP. SpoVT: From Fine-Tuning Regulator in Bacillus subtilis to Essential Sporulation Protein in Bacillus cereus. Front Microbiol 2016; 7:1607. [PMID: 27790204 PMCID: PMC5061766 DOI: 10.3389/fmicb.2016.01607] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/26/2016] [Indexed: 12/14/2022] Open
Abstract
Sporulation is a highly sophisticated developmental process adopted by most Bacilli as a survival strategy to withstand extreme conditions that normally do not support microbial growth. A complicated regulatory cascade, divided into various stages and taking place in two different compartments of the cell, involves a number of primary and secondary regulator proteins that drive gene expression directed toward the formation and maturation of an endospore. Such regulator proteins are highly conserved among various spore formers. Despite this conservation, both regulatory and phenotypic differences are observed between different species of spore forming bacteria. In this study, we demonstrate that deletion of the regulatory sporulation protein SpoVT results in a severe sporulation defect in Bacillus cereus, whereas this is not observed in Bacillus subtilis. Although spores are initially formed, the process is stalled at a later stage in development, followed by lysis of the forespore and the mother cell. A transcriptomic investigation of B. cereus ΔspoVT shows upregulation of genes involved in germination, potentially leading to premature lysis of prespores formed. Additionally, extreme variation in the expression of species-specific genes of unknown function was observed. Introduction of the B. subtilis SpoVT protein could partly restore the sporulation defect in the B. cereus spoVT mutant strain. The difference in phenotype is thus more than likely explained by differences in promoter targets rather than differences in mode of action of the conserved SpoVT regulator protein. This study stresses that evolutionary variances in regulon members of sporulation regulators can have profound effects on the spore developmental process and that mere protein homology is not a foolproof predictor of similar phenotypes.
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Affiliation(s)
- Robyn T Eijlander
- Top Institute Food and NutritionWageningen, Netherlands; Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
| | - Siger Holsappel
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen Groningen, Netherlands
| | - Anne de Jong
- Top Institute Food and NutritionWageningen, Netherlands; Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
| | - Abhinaba Ghosh
- Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge Cambridge, UK
| | - Graham Christie
- Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge Cambridge, UK
| | - Oscar P Kuipers
- Top Institute Food and NutritionWageningen, Netherlands; Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
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93
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Abstract
Bacillus subtilis is one of the best-studied organisms. Due to the broad knowledge and annotation and the well-developed genetic system, this bacterium is an excellent starting point for genome minimization with the aim of constructing a minimal cell. We have analyzed the genome of B. subtilis and selected all genes that are required to allow life in complex medium at 37°C. This selection is based on the known information on essential genes and functions as well as on gene and protein expression data and gene conservation. The list presented here includes 523 and 119 genes coding for proteins and RNAs, respectively. These proteins and RNAs are required for the basic functions of life in information processing (replication and chromosome maintenance, transcription, translation, protein folding, and secretion), metabolism, cell division, and the integrity of the minimal cell. The completeness of the selected metabolic pathways, reactions, and enzymes was verified by the development of a model of metabolism of the minimal cell. A comparison of the MiniBacillus genome to the recently reported designed minimal genome of Mycoplasma mycoides JCVI-syn3.0 indicates excellent agreement in the information-processing pathways, whereas each species has a metabolism that reflects specific evolution and adaptation. The blueprint of MiniBacillus presented here serves as the starting point for a successive reduction of the B. subtilis genome.
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94
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Schuster CF, Bellows LE, Tosi T, Campeotto I, Corrigan RM, Freemont P, Gründling A. The second messenger c-di-AMP inhibits the osmolyte uptake system OpuC in Staphylococcus aureus. Sci Signal 2016; 9:ra81. [PMID: 27531650 PMCID: PMC5248971 DOI: 10.1126/scisignal.aaf7279] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Staphylococcus aureus is an important opportunistic human pathogen that is highly resistant to osmotic stresses. To survive an increase in osmolarity, bacteria immediately take up potassium ions and small organic compounds known as compatible solutes. The second messenger cyclic diadenosine monophosphate (c-di-AMP) reduces the ability of bacteria to withstand osmotic stress by binding to and inhibiting several proteins that promote potassium uptake. We identified OpuCA, the adenosine triphosphatase (ATPase) component of an uptake system for the compatible solute carnitine, as a c-di-AMP target protein in S aureus and found that the LAC*ΔgdpP strain of S aureus, which overproduces c-di-AMP, showed reduced carnitine uptake. The paired cystathionine-β-synthase (CBS) domains of OpuCA bound to c-di-AMP, and a crystal structure revealed a putative binding pocket for c-di-AMP in the cleft between the two CBS domains. Thus, c-di-AMP inhibits osmoprotection through multiple mechanisms.
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Affiliation(s)
- Christopher F. Schuster
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Lauren E. Bellows
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Tommaso Tosi
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Ivan Campeotto
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Rebecca M. Corrigan
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Paul Freemont
- Section of Structural Biology, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Angelika Gründling
- Section of Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
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95
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Huynh TN, Choi PH, Sureka K, Ledvina HE, Campillo J, Tong L, Woodward JJ. Cyclic di-AMP targets the cystathionine beta-synthase domain of the osmolyte transporter OpuC. Mol Microbiol 2016; 102:233-243. [PMID: 27378384 DOI: 10.1111/mmi.13456] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2016] [Indexed: 12/26/2022]
Abstract
Cellular turgor is of fundamental importance to bacterial growth and survival. Changes in external osmolarity as a consequence of fluctuating environmental conditions and colonization of diverse environments can significantly impact cytoplasmic water content, resulting in cellular lysis or plasmolysis. To ensure maintenance of appropriate cellular turgor, bacteria import ions and small organic osmolytes, deemed compatible solutes, to equilibrate cytoplasmic osmolarity with the extracellular environment. Here, we show that elevated levels of c-di-AMP, a ubiquitous second messenger among bacteria, result in significant susceptibility to elevated osmotic stress in the bacterial pathogen Listeria monocytogenes. We found that levels of import of the compatible solute carnitine show an inverse correlation with intracellular c-di-AMP content and that c-di-AMP directly binds to the CBS domain of the ATPase subunit of the carnitine importer OpuC. Biochemical and structural studies identify conserved residues required for this interaction and transport activity in bacterial cells. Overall, these studies reveal a role for c-di-AMP mediated regulation of compatible solute import and provide new insight into the molecular mechanisms by which this essential second messenger impacts bacterial physiology and adaptation to changing environmental conditions.
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Affiliation(s)
- TuAnh Ngoc Huynh
- Department of Microbiology, University of Washington, Seattle, WA, 98195, USA
| | - Philip H Choi
- Department of Biological Sciences, Columbia University, New York, NY, 10027, USA
| | - Kamakshi Sureka
- Department of Microbiology, University of Washington, Seattle, WA, 98195, USA
| | - Hannah E Ledvina
- Department of Microbiology, University of Washington, Seattle, WA, 98195, USA
| | - Julian Campillo
- Department of Microbiology, University of Washington, Seattle, WA, 98195, USA
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY, 10027, USA.
| | - Joshua J Woodward
- Department of Microbiology, University of Washington, Seattle, WA, 98195, USA.
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96
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Structure–activity relationship studies of c-di-AMP synthase inhibitor, bromophenol-thiohydantoin. Tetrahedron 2016. [DOI: 10.1016/j.tet.2015.10.073] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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97
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Yongmei T, Xiaojun Y, Juan D, Wanghong Z, Xiaodan C, Jin H. [Qualitative analysis of bis-(3'-5')-cyclic dimeric adenosine monophosphate of Porphyromonas gingivalis by high performance liquid chromatography coupled with mass spectrometry]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2016; 34:307-311. [PMID: 27526459 PMCID: PMC7030827 DOI: 10.7518/hxkq.2016.03.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/18/2016] [Indexed: 06/06/2023]
Abstract
OBJECTIVE To test whether Porphyromonas gingivalis (P. gingivalis) could produce bacterial signal molecule, bis-(3'-5')-cyclic dimeric adenosine monophosphate (c-di-AMP) and lay the foundation for explorations of its roles in life metabolism and periodontitis immunity of P. gingivalis. METHODS P. gingivalis standard strain ATCC33277 was used as the experimental strain to extract nucleic acids from the bacteria. Then, c-di-AMP was detected using high performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS). Subsequently, HPLC was used to validate the sample further. RESULTS Based on the signal/noise (S/N) for 3 : 1, the limit of determination of HPLC-MS/MS for peak time of c-di-AMP standard substances was 7.49 min and nucleic acid extractions from P. gingivalis was 8.82 min (S/N > 3). Further confirmation of HPLC showed that nucleic acid extractions from both P. gingivalis and c-di-AMP standard substances pre- sented goal absorbent peaks at 15.7 min, with the same ultraviolet absorbent spectrum. CONCLUSION The nucleic acid extrac- tions from P. gingivalis contained c-di-AMP, which shows that P. gingivalis could produce c-di-AMP.
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98
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Gundlach J, Rath H, Herzberg C, Mäder U, Stülke J. Second Messenger Signaling in Bacillus subtilis: Accumulation of Cyclic di-AMP Inhibits Biofilm Formation. Front Microbiol 2016; 7:804. [PMID: 27252699 PMCID: PMC4879592 DOI: 10.3389/fmicb.2016.00804] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/11/2016] [Indexed: 12/04/2022] Open
Abstract
The Gram-positive model organism Bacillus subtilis produces the essential second messenger signaling nucleotide cyclic di-AMP. In B. subtilis and other bacteria, c-di-AMP has been implicated in diverse functions such as control of metabolism, cell division and cell wall synthesis, and potassium transport. To enhance our understanding of the multiple functions of this second messenger, we have studied the consequences of c-di-AMP accumulation at a global level by a transcriptome analysis. C-di-AMP accumulation affected the expression of about 700 genes, among them the two major operons required for biofilm formation. The expression of both operons was severely reduced both in the laboratory and a non-domesticated strain upon accumulation of c-di-AMP. In excellent agreement, the corresponding strain was unable to form complex colonies. In B. subtilis, the transcription factor SinR controls the expression of biofilm genes by binding to their promoter regions resulting in transcription repression. Inactivation of the sinR gene restored biofilm formation even at high intracellular c-di-AMP concentrations suggesting that the second messenger acts upstream of SinR in the signal transduction pathway. As c-di-AMP accumulation did not affect the intracellular levels of SinR, we conclude that the nucleotide affects the activity of SinR.
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Affiliation(s)
- Jan Gundlach
- Department of General Microbiology, Institute for Microbiology and Genetics, Georg-August-University Göttingen Göttingen, Germany
| | - Hermann Rath
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald Greifswald, Germany
| | - Christina Herzberg
- Department of General Microbiology, Institute for Microbiology and Genetics, Georg-August-University Göttingen Göttingen, Germany
| | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald Greifswald, Germany
| | - Jörg Stülke
- Department of General Microbiology, Institute for Microbiology and Genetics, Georg-August-University Göttingen Göttingen, Germany
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99
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Opoku-Temeng C, Sintim HO. Inhibition of cyclic diadenylate cyclase, DisA, by polyphenols. Sci Rep 2016; 6:25445. [PMID: 27150552 PMCID: PMC4858736 DOI: 10.1038/srep25445] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 04/15/2016] [Indexed: 12/27/2022] Open
Abstract
Cyclic di-AMP has emerged as an important signaling molecule that controls a myriad of functions, including cell wall homeostasis in different bacteria. Polyphenols display various biological activities and tea polyphenols in particular have been shown to possess among other properties antioxidant and antibacterial activities. Certain tea polyphenols, such as catechin and epigallocatechin gallate, have been used to augment the action of traditional antibiotics that target the cell wall. Considering the expanding role played by cyclic dinucleotides in bacteria, we investigated whether the action of polyphenols on bacteria could be due in part to modulation of c-di-AMP signaling. Out of 14 tested polyphenols, tannic acid (TA), theaflavin-3'-gallate (TF2B) and theaflavin-3,3'-digallate (TF3) exhibited inhibitory effects on B. subtilis c-di-AMP synthase, DisA. TF2B and TF3 specifically inhibited DisA but not YybT (a PDE) whilst TA was more promiscuous and inhibited both DisA and YybT.
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Affiliation(s)
- Clement Opoku-Temeng
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.,Center for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA.,Graduate program in Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Herman O Sintim
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.,Center for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA
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Abstract
The cyclic dinucleotides cyclic 3′,5′-diguanylate (c-di-GMP) and cyclic 3′,5′-diadenylate (c-di-AMP) have emerged as key components of bacterial signal transduction networks. These closely related second messengers follow the classical general principles of nucleotide signaling by integrating diverse signals into regulatory pathways that control cellular responses to changing environments. They impact distinct cellular processes, with c-di-GMP having an established role in promoting bacterial adhesion and inhibiting motility and c-di-AMP being involved in cell wall metabolism, potassium homeostasis, and DNA repair. The involvement of c-dinucleotides in the physiology of the filamentous, nonmotile streptomycetes remained obscure until recent discoveries showed that c-di-GMP controls the activity of the developmental master regulator BldD and that c-di-AMP determines the level of the resuscitation-promoting factor A(RpfA) cell wall-remodelling enzyme. Here, I summarize our current knowledge of c-dinucleotide signaling in Streptomyces species and highlight the important roles of c-di-GMP and c-di-AMP in the biology of these antibiotic-producing, multicellular bacteria.
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