1
|
Yadav M, Ghosh S, Sen U. Crystal structure of the complex between cyclic-di-inosine monophosphate and the Vibrio cholerae standalone phosphodiesterase (VcEAL) at 2.2 Å. Biochem Biophys Res Commun 2024; 737:150535. [PMID: 39137586 DOI: 10.1016/j.bbrc.2024.150535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2024] [Revised: 08/02/2024] [Accepted: 08/09/2024] [Indexed: 08/15/2024]
Abstract
Cyclic dinucleotides (CDNs) are a significant and expanding class of secondary messengers that influence several vital bacterial physiological functions. Therefore, an understanding of the process by which CDNs are degraded by their cognate PDEs is crucial for comprehending a variety of cellular processes, such as the formation and dissemination of biofilms. As an alternative, it might be beneficial to create and/or identify non-hydrolyzable CDN derivatives to employ them as chemical probes of cyclic-di-GMP (c-di-GMP) signaling. Cyclic-di-inosine monophosphate, or c-di-IMP, is not a naturally occurring signaling molecule in biological systems, but it has strong adjuvant effects on metazoans and functions as an immunological modulator and stimulant. Here we report the first structural details of c-di-IMP and EAL interaction through high-resolution (2.2 Å) crystal structure of VcEAL in complex with c-di-IMP + Ca2+. Comparison of the VcEAL structures bound with cyclic-di-GMP (c-di-GMP), 3',5'-cyclic-AMP-GMP (cGAMP) and c-di-IMP and the structural variations at the chemical level between these CDNs provides their structural basis of recognition and rate of hydrolysis.
Collapse
Affiliation(s)
- Malti Yadav
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhan Nagar, Kolkata, 700064, India
| | - Shrestha Ghosh
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhan Nagar, Kolkata, 700064, India
| | - Udayaditya Sen
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhan Nagar, Kolkata, 700064, India.
| |
Collapse
|
2
|
Sasazawa M, Tomares DT, Childers WS, Saurabh S. Biomolecular condensates as stress sensors and modulators of bacterial signaling. PLoS Pathog 2024; 20:e1012413. [PMID: 39146259 PMCID: PMC11326607 DOI: 10.1371/journal.ppat.1012413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2024] Open
Abstract
Microbes exhibit remarkable adaptability to environmental fluctuations. Signaling mechanisms, such as two-component systems and secondary messengers, have long been recognized as critical for sensing and responding to environmental cues. However, recent research has illuminated the potential of a physical adaptation mechanism in signaling-phase separation, which may represent a ubiquitous mechanism for compartmentalizing biochemistry within the cytoplasm in the context of bacteria that frequently lack membrane-bound organelles. This review considers the broader prospect that phase separation may play critical roles as rapid stress sensing and response mechanisms within pathogens. It is well established that weak multivalent interactions between disordered regions, coiled-coils, and other structured domains can form condensates via phase separation and be regulated by specific environmental parameters in some cases. The process of phase separation itself acts as a responsive sensor, influenced by changes in protein concentration, posttranslational modifications, temperature, salts, pH, and oxidative stresses. This environmentally triggered phase separation can, in turn, regulate the functions of recruited biomolecules, providing a rapid response to stressful conditions. As examples, we describe biochemical pathways organized by condensates that are essential for cell physiology and exhibit signaling features. These include proteins that organize and modify the chromosome (Dps, Hu, SSB), regulate the decay, and modification of RNA (RNase E, Hfq, Rho, RNA polymerase), those involved in signal transduction (PopZ, PodJ, and SpmX) and stress response (aggresomes and polyphosphate granules). We also summarize the potential of proteins within pathogens to function as condensates and the potential and challenges in targeting biomolecular condensates for next-generation antimicrobial therapeutics. Together, this review illuminates the emerging significance of biomolecular condensates in microbial signaling, stress responses, and regulation of cell physiology and provides a framework for microbiologists to consider the function of biomolecular condensates in microbial adaptation and response to diverse environmental conditions.
Collapse
Affiliation(s)
- Moeka Sasazawa
- Department of Chemistry, New York University, New York, New York, United States of America
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Saumya Saurabh
- Department of Chemistry, New York University, New York, New York, United States of America
| |
Collapse
|
3
|
Meireles D, Pombinho R, Cabanes D. Signals behind Listeria monocytogenes virulence mechanisms. Gut Microbes 2024; 16:2369564. [PMID: 38979800 PMCID: PMC11236296 DOI: 10.1080/19490976.2024.2369564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 06/13/2024] [Indexed: 07/10/2024] Open
Abstract
The tight and coordinated regulation of virulence gene expression is crucial to ensure the survival and persistence of bacterial pathogens in different contexts within their hosts. Considering this, bacteria do not express virulence factors homogenously in time and space, either due to their associated fitness cost or to their detrimental effect at specific infection stages. To efficiently infect and persist into their hosts, bacteria have thus to monitor environmental cues or chemical cell-to-cell signaling mechanisms that allow their transition from the external environment to the host, and therefore adjust gene expression levels, intrinsic biological activities, and appropriate behaviors. Listeria monocytogenes (Lm), a major Gram-positive facultative intracellular pathogen, stands out for its adaptability and capacity to thrive in a wide range of environments. Because of that, Lm presents itself as a significant concern in food safety and public health, that can lead to potentially life-threatening infections in humans. A deeper understanding of the intricate bacterial virulence mechanisms and the signals that control them provide valuable insights into the dynamic interplay between Lm and the host. Therefore, this review addresses the role of some crucial signals behind Lm pathogenic virulence mechanisms and explores how the ability to assimilate and interpret these signals is fundamental for pathogenesis, identifying potential targets for innovative antimicrobial strategies.
Collapse
Affiliation(s)
- Diana Meireles
- Instituto de Investigação e Inovação em Saúde, Porto, Portugal
- Group of Molecular Microbiology, IBMC, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar – ICBAS, Porto, Portugal
| | - Rita Pombinho
- Instituto de Investigação e Inovação em Saúde, Porto, Portugal
- Group of Molecular Microbiology, IBMC, Porto, Portugal
| | - Didier Cabanes
- Instituto de Investigação e Inovação em Saúde, Porto, Portugal
- Group of Molecular Microbiology, IBMC, Porto, Portugal
| |
Collapse
|
4
|
Marotta NJ, Weinert EE. Insights into the metabolism, signaling, and physiological effects of 2',3'-cyclic nucleotide monophosphates in bacteria. Crit Rev Biochem Mol Biol 2023; 58:118-131. [PMID: 38064689 PMCID: PMC10877235 DOI: 10.1080/10409238.2023.2290473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 11/20/2023] [Indexed: 02/03/2024]
Abstract
2',3'-cyclic nucleotide monophosphates (2',3'-cNMPs) have been discovered within both prokaryotes and eukaryotes in the past decade and a half, raising questions about their conserved existence in cells. In plants and mammals, wounding has been found to cause increased levels of 2',3'-cNMPs. Roles for 2',3'-cNMPs in plant immunity suggest that their regulation may be valuable for both plant hosts and microbial pathogens. In support of this hypothesis, a plethora of microbial enzymes have been found with activities related to these molecules. Studies in bacteria suggest that 2',3'-cNMPs are also produced in response to cellular stress and modulate expression of numerous genes. 2',3'-cNMP levels affect bacterial phenotypes, including biofilm formation, motility, and growth. Within E. coli and Salmonella enterica, 2',3'-cNMPs are produced by RNA degradation by RNase I, highlighting potential roles for Type 2 RNases producing 2',3'-cNMPs in a range of organisms. Development of cellular tools to modulate 2',3'-cNMP levels in bacteria has allowed for interrogation of the effects of 2',3'-cNMP concentration on bacterial transcriptomes and physiology. Pull-downs of cellular 2',3'-cNMP binding proteins have identified the ribosome and in vitro studies demonstrated that 2',3'-cNMPs decrease translation, suggesting a direct mechanism for 2',3-cNMP-dependent control of bacterial phenotypes. Future studies dissecting the cellular roles of 2',3'-cNMPs will highlight novel signaling pathways within prokaryotes and which can potentially be engineered to control bacterial physiology.
Collapse
Affiliation(s)
- Nick J. Marotta
- Graduate Program in Molecular, Cellular, and Integrative
Biosciences, Penn State University, University Park, PA, 16803, USA
| | - Emily E. Weinert
- Department of Biochemistry and Molecular Biology, Penn
State University, University Park, PA, 16803, USA
- Department of Chemistry, Penn State University, University
Park, PA, 16803, USA
| |
Collapse
|
5
|
Hoque NJ, Weinert EE. Control of bacterial second messenger signaling and motility by heme-based direct oxygen-sensing proteins. Curr Opin Microbiol 2023; 76:102396. [PMID: 37864983 DOI: 10.1016/j.mib.2023.102396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/15/2023] [Accepted: 09/21/2023] [Indexed: 10/23/2023]
Abstract
Bacteria sense and respond to their environment, allowing them to maximize their survival and growth under changing conditions, such as oxygen levels. Direct oxygen-sensing proteins allow bacteria to rapidly sense concentration changes and adapt by regulating signaling pathways and/or cellular machinery. Recent work has identified roles for direct oxygen-sensing proteins in controlling second messenger levels and motility machinery, as well as effects on biofilm formation, virulence, and motility. In this review, we discuss recent progress in understanding O2-dependent regulation of cyclic di-GMP signaling and motility and highlight the emerging importance in controlling bacterial physiology and behavior.
Collapse
Affiliation(s)
- Nushrat J Hoque
- Department of Chemistry, Penn State University, University Park, PA 16802, USA
| | - Emily E Weinert
- Department of Chemistry, Penn State University, University Park, PA 16802, USA; Department of Biochemistry & Molecular Biology, Penn State University, University Park, PA 16802, USA.
| |
Collapse
|
6
|
Faozia S, Hossain T, Cho KH. The Dlt and LiaFSR systems derepress SpeB production independently in the Δpde2 mutant of Streptococcus pyogenes. Front Cell Infect Microbiol 2023; 13:1293095. [PMID: 38029265 PMCID: PMC10679467 DOI: 10.3389/fcimb.2023.1293095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023] Open
Abstract
The second messenger molecule, c-di-AMP, plays a critical role in pathogenesis and virulence in S. pyogenes. We previously reported that deleting the c-di-AMP phosphodiesterase gene pde2 severely suppresses SpeB production at the transcriptional level. We performed transposon mutagenesis to gain insight into the mechanism of how Pde2 is involved in SpeB regulation. We identified one of the genes of the dlt operon, dltX, as a suppressor of the SpeB-null phenotype of the Δpde2 mutant. The dlt operon consists of five genes, dltX, dltA, dltB, dltC, and dltD in many Gram-positive bacteria, and its function is to incorporate D-alanine into lipoteichoic acids. DltX, a small membrane protein, is a newly identified member of the operon. The in-frame deletion of dltX or insertional inactivation of dltA in the Δpde2 mutant restored SpeB production, indicating that D-alanylation is crucial for the suppressor phenotype. These mutations did not affect the growth in lab media but showed increased negative cell surface charge and enhanced sensitivity to polymyxin B. Considering that dlt mutations change cell surface charge and sensitivity to cationic antimicrobial peptides, we examined the LiaFSR system that senses and responds to cell envelope stress. The ΔliaR mutation in the Δpde2 mutant also derepressed SpeB production, like the ΔdltX mutation. LiaFSR controls speB expression by regulating the expression of the transcriptional regulator SpxA2. However, the Dlt system did not regulate spxA2 expression. The SpeB phenotype of the Δpde2ΔdltX mutant in higher salt media differed from that of the Δpde2ΔliaR mutant, suggesting a unique pathway for the Dlt system in SpeB production, possibly related to ion transport or turgor pressure regulation.
Collapse
Affiliation(s)
| | | | - Kyu Hong Cho
- Department of Biology, Indiana State University, Terre Haute, IN, United States
| |
Collapse
|
7
|
Toida K, Kushida W, Yamamoto H, Yamamoto K, Ishii K, Uesaka K, Kanaly RA, Kutsuna S, Ihara K, Fujita Y, Iwasaki H. The GGDEF protein Dgc2 suppresses both motility and biofilm formation in the filamentous cyanobacterium Leptolyngbya boryana. Microbiol Spectr 2023; 11:e0483722. [PMID: 37655901 PMCID: PMC10581220 DOI: 10.1128/spectrum.04837-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 06/30/2023] [Indexed: 09/02/2023] Open
Abstract
Colony pattern formations of bacteria with motility manifest complicated morphological self-organization phenomena. Leptolyngbya boryana is a filamentous cyanobacterium, which has been used as a genetic model organism for studying metabolism including photosynthesis and nitrogen fixation. A widely used type strain [wild type (WT) in this article] of this species has not been reported to show any motile activity. However, we isolated a spontaneous mutant strain that shows active motility (gliding activity) to give rise to complicated colony patterns, including comet-like wandering clusters and disk-like rotating vortices on solid media. Whole-genome resequencing identified multiple mutations in the genome of the mutant strain. We confirmed that inactivation of the candidate gene dgc2 (LBDG_02920) in the WT background was sufficient to give rise to motility and morphologically complex colony patterns. This gene encodes a protein containing the GGDEF motif which is conserved at the catalytic domain of diguanylate cyclase (DGC). Although DGC has been reported to be involved in biofilm formation, the dgc2 mutant significantly facilitated biofilm formation, suggesting a role for the dgc2 gene in suppressing both gliding motility and biofilm formation. Thus, Leptolyngbya is expected to be an excellent genetic model for studying dynamic colony pattern formation and to provide novel insights into the role of DGC family genes in biofilm formation. IMPORTANCE Self-propelled bacteria often exhibit complex collective behaviors, such as formation of dense-moving clusters, which are exemplified by wandering comet-like and rotating disk-like colonies; however, the molecular details of how these structures are formed are scant. We found that a strain of the filamentous cyanobacterium Leptolyngbya deficient in the GGDEF protein gene dgc2 elicits motility and complex and dynamic colony pattern formation, including comet-like and disk-like clusters. Although c-di-GMP has been reported to activate biofilm formation in some bacterial species, disruption of dgc2 unexpectedly enhanced it, suggesting a novel role for this GGDEF protein for inhibiting both colony pattern formation and biofilm formation.
Collapse
Affiliation(s)
- Kazuma Toida
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, TWIns, Waseda University, Tokyo, Japan
| | - Wakana Kushida
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, TWIns, Waseda University, Tokyo, Japan
| | - Hiroki Yamamoto
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, TWIns, Waseda University, Tokyo, Japan
| | - Kyoka Yamamoto
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, TWIns, Waseda University, Tokyo, Japan
| | - Kaichi Ishii
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, TWIns, Waseda University, Tokyo, Japan
| | - Kazuma Uesaka
- Center for Gene Research, Nagoya University, Nagoya, Japan
| | - Robert A. Kanaly
- Graduate School of Nanobioscience, Yokohama City University, Yokohama, Japan
| | - Shinsuke Kutsuna
- Graduate School of Nanobioscience, Yokohama City University, Yokohama, Japan
| | - Kunio Ihara
- Center for Gene Research, Nagoya University, Nagoya, Japan
| | - Yuichi Fujita
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Hideo Iwasaki
- Department of Electrical Engineering and Bioscience, Graduate School of Sciences and Engineering, TWIns, Waseda University, Tokyo, Japan
- metaPhorest, Bioaesthetics Platform, Waseda University, Tokyo, Japan
| |
Collapse
|
8
|
Huang C, Li W, Chen J. Stringent Response Factor DksA Contributes to Fatty Acid Degradation Function to Influence Cell Membrane Stability and Polymyxin B Resistance of Yersinia enterocolitica. Int J Mol Sci 2023; 24:11951. [PMID: 37569327 PMCID: PMC10418728 DOI: 10.3390/ijms241511951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/19/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
DksA is a proteobacterial regulator that binds directly to the secondary channel of RNA polymerase with (p)ppGpp and is responsible for various bacterial physiological activities. While (p)ppGpp is known to be involved in the regulation and response of fatty acid metabolism pathways in many foodborne pathogens, the role of DksA in this process has yet to be clarified. This study aimed to characterize the function of DksA on fatty acid metabolism and cell membrane structure in Yersinia enterocolitica. Therefore, comparison analysis of gene expression, growth conditions, and membrane permeabilization among the wide-type (WT), DksA-deficient mutant (YEND), and the complemented strain was carried out. It confirmed that deletion of DksA led to a more than four-fold decrease in the expression of fatty acid degradation genes, including fadADEIJ. Additionally, YEND exhibited a smaller growth gap compared to the WT strain at low temperatures, indicating that DksA is not required for the growth of Y. enterocolitica in cold environments. Given that polymyxin B is a cationic antimicrobial peptide that targets the cell membrane, the roles of DksA under polymyxin B exposure were also characterized. It was found that DksA positively regulates the integrity of the inner and outer membranes of Y. enterocolitica under polymyxin B, preventing the leakage of intracellular nucleic acids and proteins and ultimately reducing the sensitivity of Y. enterocolitica to polymyxin B. Taken together, this study provides insights into the functions of DksA and paves the way for novel fungicide development.
Collapse
Affiliation(s)
| | | | - Jingyu Chen
- Beijing Laboratory for Food Quality and Safety, College of Food Science & Nutritional Engineering, China Agricultural University, 17 Qinghua East Rd., Beijing 100083, China
| |
Collapse
|
9
|
Wang Y, Jin Y, Sun F, Zhang Y, Liu Q, Wang Q, Yang D, Zhang Y. The c-di-GMP signalling component YfiR regulates multiple bacterial phenotypes and virulence in Pseudomonas plecoglossicida. J Appl Microbiol 2023; 134:lxad157. [PMID: 37500265 DOI: 10.1093/jambio/lxad157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 07/12/2023] [Accepted: 07/26/2023] [Indexed: 07/29/2023]
Abstract
AIMS Pseudomonas plecoglossicida (P. plecoglossicida) is the causative agent of visceral granulomas disease in large yellow croaker (Larimichthys crocea) and it causes severe economic loss to its industry. Biofilm formation, related to intracellular cyclic bis (3'-5') diguanylic acid (c-di-GMP) levels, is essential for the lifestyle of P. plecoglossicida. This research aims to investigate the role of YfiR-a key regulator of the diguanylate cyclase YfiN to regulate c-di-GMP levels and reveal its regulatory function of bacterial virulence expression in P. plecoglossicida. METHODS AND RESULTS A genetic analysis was carried out to identify the yfiBNR operon for c-di-GMP regulation in P. plecoglossicida. Then, we constructed a yfiR mutant and observed increased c-di-GMP levels, enhanced biofilm formation, increased exopolysaccharides, and diminished swimming and swarming motility in this strain. Moreover, through establishing a yolk sac microinjection infection model in zebrafish larvae, an attenuated phenotype of yfiR mutant that manifested as restored survival and lower bacterial colonization was found. CONCLUSIONS YfiR is the key regulator of virulence in P. plecoglossicida, which contributes to c-di-GMP level, biofilm formation, exopolysaccharides production, swimming, swarming motility, and bacterial colonization in zebrafish model.
Collapse
Affiliation(s)
- Ying Wang
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai 200237, China
| | - Yinhua Jin
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai 200237, China
| | - Fei Sun
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai 200237, China
| | - Yuanxing Zhang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai 200237, China
| | - Qin Liu
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai 200237, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai 200237, China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai 200237, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai 200237, China
| | - Dahai Yang
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai 200237, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai 200237, China
| | - Yibei Zhang
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai 200237, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai 200237, China
| |
Collapse
|
10
|
Alonso-Vásquez T, Fondi M, Perrin E. Understanding Antimicrobial Resistance Using Genome-Scale Metabolic Modeling. Antibiotics (Basel) 2023; 12:antibiotics12050896. [PMID: 37237798 DOI: 10.3390/antibiotics12050896] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/28/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023] Open
Abstract
The urgent necessity to fight antimicrobial resistance is universally recognized. In the search of new targets and strategies to face this global challenge, a promising approach resides in the study of the cellular response to antimicrobial exposure and on the impact of global cellular reprogramming on antimicrobial drugs' efficacy. The metabolic state of microbial cells has been shown to undergo several antimicrobial-induced modifications and, at the same time, to be a good predictor of the outcome of an antimicrobial treatment. Metabolism is a promising reservoir of potential drug targets/adjuvants that has not been fully exploited to date. One of the main problems in unraveling the metabolic response of cells to the environment resides in the complexity of such metabolic networks. To solve this problem, modeling approaches have been developed, and they are progressively gaining in popularity due to the huge availability of genomic information and the ease at which a genome sequence can be converted into models to run basic phenotype predictions. Here, we review the use of computational modeling to study the relationship between microbial metabolism and antimicrobials and the recent advances in the application of genome-scale metabolic modeling to the study of microbial responses to antimicrobial exposure.
Collapse
Affiliation(s)
- Tania Alonso-Vásquez
- Department of Biology, University of Florence, Via Madonna del Piano 6, Sesto F.no, 50019 Florence, Italy
| | - Marco Fondi
- Department of Biology, University of Florence, Via Madonna del Piano 6, Sesto F.no, 50019 Florence, Italy
| | - Elena Perrin
- Department of Biology, University of Florence, Via Madonna del Piano 6, Sesto F.no, 50019 Florence, Italy
| |
Collapse
|
11
|
Huang C, Li W, Chen J. Transcriptomic Analysis Reveals Key Roles of (p)ppGpp and DksA in Regulating Metabolism and Chemotaxis in Yersinia enterocolitica. Int J Mol Sci 2023; 24:ijms24087612. [PMID: 37108773 PMCID: PMC10142893 DOI: 10.3390/ijms24087612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/14/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
The stringent response is a rapid response system that is ubiquitous in bacteria, allowing them to sense changes in the external environment and undergo extensive physiological transformations. However, the regulators (p)ppGpp and DksA have extensive and complex regulatory patterns. Our previous studies demonstrated that (p)ppGpp and DksA in Yersinia enterocolitica positively co-regulated motility, antibiotic resistance, and environmental tolerance but had opposite roles in biofilm formation. To reveal the cellular functions regulated by (p)ppGpp and DksA comprehensively, the gene expression profiles of wild-type, ΔrelA, ΔrelAΔspoT, and ΔdksAΔrelAΔspoT strains were compared using RNA-Seq. Results showed that (p)ppGpp and DksA repressed the expression of ribosomal synthesis genes and enhanced the expression of genes involved in intracellular energy and material metabolism, amino acid transport and synthesis, flagella formation, and the phosphate transfer system. Additionally, (p)ppGpp and DksA inhibited amino acid utilization (such as arginine and cystine) and chemotaxis in Y. enterocolitica. Overall, the results of this study unraveled the link between (p)ppGpp and DksA in the metabolic networks, amino acid utilization, and chemotaxis in Y. enterocolitica and enhanced the understanding of stringent responses in Enterobacteriaceae.
Collapse
Affiliation(s)
- Can Huang
- Beijing Laboratory for Food Quality and Safety, College of Food Science & Nutritional Engineering, China Agricultural University, 17 Qinghua East Rd., Beijing 100083, China
| | - Wenqian Li
- Beijing Laboratory for Food Quality and Safety, College of Food Science & Nutritional Engineering, China Agricultural University, 17 Qinghua East Rd., Beijing 100083, China
| | - Jingyu Chen
- Beijing Laboratory for Food Quality and Safety, College of Food Science & Nutritional Engineering, China Agricultural University, 17 Qinghua East Rd., Beijing 100083, China
| |
Collapse
|
12
|
Nolan AC, Zeden MS, Kviatkovski I, Campbell C, Urwin L, Corrigan RM, Gründling A, O’Gara JP. Purine Nucleosides Interfere with c-di-AMP Levels and Act as Adjuvants To Re-Sensitize MRSA To β-Lactam Antibiotics. mBio 2023; 14:e0247822. [PMID: 36507833 PMCID: PMC9973305 DOI: 10.1128/mbio.02478-22] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/17/2022] [Indexed: 12/14/2022] Open
Abstract
The purine-derived signaling molecules c-di-AMP and (p)ppGpp control mecA/PBP2a-mediated β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) raise the possibility that purine availability can control antibiotic susceptibility. Consistent with this, exogenous guanosine and xanthosine, which are fluxed through the GTP branch of purine biosynthesis, were shown to significantly reduce MRSA β-lactam resistance. In contrast, adenosine (fluxed to ATP) significantly increased oxacillin resistance, whereas inosine (which can be fluxed to ATP and GTP via hypoxanthine) only marginally increased oxacillin susceptibility. Furthermore, mutations that interfere with de novo purine synthesis (pur operon), transport (NupG, PbuG, PbuX) and the salvage pathway (DeoD2, Hpt) increased β-lactam resistance in MRSA strain JE2. Increased resistance of a nupG mutant was not significantly reversed by guanosine, indicating that NupG is required for guanosine transport, which is required to reduce β-lactam resistance. Suppressor mutants resistant to oxacillin/guanosine combinations contained several purine salvage pathway mutations, including nupG and hpt. Guanosine significantly increased cell size and reduced levels of c-di-AMP, while inactivation of GdpP, the c-di-AMP phosphodiesterase negated the impact of guanosine on β-lactam susceptibility. PBP2a expression was unaffected in nupG or deoD2 mutants, suggesting that guanosine-induced β-lactam susceptibility may result from dysfunctional c-di-AMP-dependent osmoregulation. These data reveal the therapeutic potential of purine nucleosides, as β-lactam adjuvants that interfere with the normal activation of c-di-AMP are required for high-level β-lactam resistance in MRSA. IMPORTANCE The clinical burden of infections caused by antimicrobial resistant (AMR) pathogens is a leading threat to public health. Maintaining the effectiveness of existing antimicrobial drugs or finding ways to reintroduce drugs to which resistance is widespread is an important part of efforts to address the AMR crisis. Predominantly, the safest and most effective class of antibiotics are the β-lactams, which are no longer effective against methicillin-resistant Staphylococcus aureus (MRSA). Here, we report that the purine nucleosides guanosine and xanthosine have potent activity as adjuvants that can resensitize MRSA to oxacillin and other β-lactam antibiotics. Mechanistically, exposure of MRSA to these nucleosides significantly reduced the levels of the cyclic dinucleotide c-di-AMP, which is required for β-lactam resistance. Drugs derived from nucleotides are widely used in the treatment of cancer and viral infections highlighting the clinical potential of using purine nucleosides to restore or enhance the therapeutic effectiveness of β-lactams against MRSA and potentially other AMR pathogens.
Collapse
Affiliation(s)
- Aaron C. Nolan
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Ireland
| | - Merve S. Zeden
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Ireland
| | - Igor Kviatkovski
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Christopher Campbell
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Ireland
| | - Lucy Urwin
- The Florey Institute, School of Bioscience, University of Sheffield, Sheffield, United Kingdom
| | - Rebecca M. Corrigan
- The Florey Institute, School of Bioscience, University of Sheffield, Sheffield, United Kingdom
| | - Angelika Gründling
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - James P. O’Gara
- Microbiology, School of Biological and Chemical Sciences, University of Galway, Ireland
| |
Collapse
|
13
|
Baek J, Yoon H. Cyclic di-GMP Modulates a Metabolic Flux for Carbon Utilization in Salmonella enterica Serovar Typhimurium. Microbiol Spectr 2023; 11:e0368522. [PMID: 36744926 PMCID: PMC10100716 DOI: 10.1128/spectrum.03685-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 01/16/2023] [Indexed: 02/07/2023] Open
Abstract
Salmonella enterica serovar Typhimurium is an enteric pathogen spreading via the fecal-oral route. Transmission across humans, animals, and environmental reservoirs has forced this pathogen to rapidly respond to changing environments and adapt to new environmental conditions. Cyclic di-GMP (c-di-GMP) is a second messenger that controls the transition between planktonic and sessile lifestyles, in response to environmental cues. Our study reveals the potential of c-di-GMP to alter the carbon metabolic pathways in S. Typhimurium. Cyclic di-GMP overproduction decreased the transcription of genes that encode components of three phosphoenolpyruvate (PEP):carbohydrate phosphotransferase systems (PTSs) allocated for the uptake of glucose (PTSGlc), mannose (PTSMan), and fructose (PTSFru). PTS gene downregulation by c-di-GMP was alleviated in the absence of the three regulators, SgrS, Mlc, and Cra, suggesting their intermediary roles between c-di-GMP and PTS regulation. Moreover, Cra was found to bind to the promoters of ptsG, manX, and fruB. In contrast, c-di-GMP increased the transcription of genes important for gluconeogenesis. However, this effect of c-di-GMP in gluconeogenesis disappeared in the absence of Cra, indicating that Cra is a pivotal regulator that coordinates the carbon flux between PTS-mediated sugar uptake and gluconeogenesis, in response to cellular c-di-GMP concentrations. Since gluconeogenesis supplies precursor sugars required for extracellular polysaccharide production, Salmonella may exploit c-di-GMP as a dual-purpose signal that rewires carbon flux from glycolysis to gluconeogenesis and promotes biofilm formation using the end products of gluconeogenesis. This study sheds light on a new role for c-di-GMP in modulating carbon flux, to coordinate bacterial behavior in response to hostile environments. IMPORTANCE Cyclic di-GMP is a central signaling molecule that determines the transition between motile and nonmotile lifestyles in many bacteria. It stimulates biofilm formation at high concentrations but leads to biofilm dispersal and planktonic status at low concentrations. This study provides new insights into the role of c-di-GMP in programming carbon metabolic pathways. An increase in c-di-GMP downregulated the expression of PTS genes important for sugar uptake, while simultaneously upregulating the transcription of genes important for bacterial gluconeogenesis. The directly opposing effects of c-di-GMP on sugar metabolism were mediated by Cra (catabolite repressor/activator), a dual transcriptional regulator that modulates the direction of carbon flow. Salmonella may potentially harness c-di-GMP to promote its survival and fitness in hostile environments via the coordination of carbon metabolic pathways and the induction of biofilm formation.
Collapse
Affiliation(s)
- Jiwon Baek
- Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea
| | - Hyunjin Yoon
- Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea
- Department of Applied Chemistry and Biological Engineering, Ajou University, Suwon, Republic of Korea
| |
Collapse
|
14
|
Chauhan SS, Weinert EE. Generation of nucleotide-linked resins for identification of novel binding proteins. Methods Enzymol 2023; 679:323-330. [PMID: 36682867 DOI: 10.1016/bs.mie.2022.08.052] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Organisms use numerous nucleotide-containing compounds as intracellular signals to control behavior. Identifying the biomolecules responsible to sensing and responding to changes in signaling molecule concentration is an important area of research. However, identifying the binding proteins can be challenging when there is no prior information available about binding motifs. In this chapter, we describe a straightforward method to generate nucleotide-linked resins for use in pull-down experiments to identify binding proteins. The protocol outlined in this chapter also can be adapted to generate custom resins linked to other molecules of interest.
Collapse
Affiliation(s)
- Shikha S Chauhan
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, United States
| | - Emily E Weinert
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, United States; Department of Chemistry, Pennsylvania State University, University Park, PA, United States.
| |
Collapse
|
15
|
Stress-Associated and Growth-Dependent Mutagenesis Are Divergently Regulated by c-di-AMP Levels in Bacillus subtilis. Int J Mol Sci 2022; 24:ijms24010455. [PMID: 36613897 PMCID: PMC9820435 DOI: 10.3390/ijms24010455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/11/2022] [Accepted: 12/19/2022] [Indexed: 12/29/2022] Open
Abstract
A previous proteomic study uncovered a relationship between nutritional stress and fluctuations in levels of diadenylate cyclases (DACs) and other proteins that regulate DAC activity, degrade, or interact with c-di-AMP, suggesting a possible role of this second messenger in B. subtilis stress-associated mutagenesis (SAM). Here, we investigated a possible role of c-di-AMP in SAM and growth-associated mutagenesis (GAM). Our results showed that in growing cells of B. subtilis YB955 (hisC952, metB25 and leuC427), the DACs CdaA and DisA, which play crucial roles in cell wall homeostasis and chromosomal fidelity, respectively, counteracted spontaneous and Mitomycin-C-induced mutagenesis. However, experiments in which hydrogen peroxide was used to induce mutations showed that single deficiencies in DACs caused opposite effects compared to each other. In contrast, in the stationary-phase, DACs promoted mutations in conditions of nutritional stress. These results tracked with intracellular levels of c-di-AMP, which are significantly lower in cdaA- and disA-deficient strains. The restoration of DAC-deficient strains with single functional copies of the cdaA and/or disA returned SAM and GAM levels to those observed in the parental strain. Taken together, these results reveal a role for c-di-AMP in promoting genetic diversity in growth-limiting conditions in B. subtilis. Finally, we postulate that this novel function of c-di-AMP can be exerted through proteins that possess binding domains for this second messenger and play roles in DNA repair, ion transport, transcriptional regulation, as well as oxidative stress protection.
Collapse
|
16
|
Huang J, Yao C, Sun Y, Ji Q, Deng X. Virulence-related regulatory network of Pseudomonas syringae. Comput Struct Biotechnol J 2022; 20:6259-6270. [PMID: 36420163 PMCID: PMC9678800 DOI: 10.1016/j.csbj.2022.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 11/05/2022] [Accepted: 11/05/2022] [Indexed: 11/11/2022] Open
Abstract
Transcription factors (TFs) play important roles in regulating multiple biological processes by binding to promoter regions and regulating the global gene transcription levels. Pseudomonas syringae is a Gram-negative phytopathogenic bacterium harbouring 301 putative TFs in its genome, approximately 50 of which are responsible for virulence-related gene and pathway regulation. Over the past decades, RNA sequencing, chromatin immunoprecipitation sequencing, high-throughput systematic evolution of ligands by exponential enrichment, and other technologies have been applied to identify the functions of master regulators and their interactions in virulence-related pathways. This review summarises the recent advances in the regulatory networks of TFs involved in the type III secretion system (T3SS) and non-T3SS virulence-associated pathways, including motility, biofilm formation, quorum sensing, nucleotide-based secondary messengers, phytotoxins, siderophore production, and oxidative stress. Moreover, this review discusses the future perspectives in terms of TF-mediated pathogenesis mechanisms and provides novel insights that will help combat P. syringae infections based on the regulatory networks of TFs.
Collapse
Affiliation(s)
- Jiadai Huang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077 China
| | - Chunyan Yao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077 China
| | - Yue Sun
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077 China
| | - Quanjiang Ji
- Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR 999077 China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
| |
Collapse
|
17
|
Moradali MF, Ghods S, Bähre H, Lamont RJ, Scott DA, Seifert R. Atypical cyclic di-AMP signaling is essential for Porphyromonas gingivalis growth and regulation of cell envelope homeostasis and virulence. NPJ Biofilms Microbiomes 2022; 8:53. [PMID: 35794154 PMCID: PMC9259658 DOI: 10.1038/s41522-022-00316-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 06/13/2022] [Indexed: 02/04/2023] Open
Abstract
Microbial pathogens employ signaling systems through cyclic (di-) nucleotide monophosphates serving as second messengers to increase fitness during pathogenesis. However, signaling schemes via second messengers in Porphyromonas gingivalis, a key Gram-negative anaerobic oral pathogen, remain unknown. Here, we report that among various ubiquitous second messengers, P. gingivalis strains predominantly synthesize bis-(3',5')-cyclic di-adenosine monophosphate (c-di-AMP), which is essential for their growth and survival. Our findings demonstrate an unusual regulation of c-di-AMP synthesis in P. gingivalis. P. gingivalis c-di-AMP phosphodiesterase (PDE) gene (pdepg) positively regulates c-di-AMP synthesis and impedes a decrease in c-di-AMP concentration despite encoding conserved amino acid motifs for phosphodiesterase activity. Instead, the predicted regulator gene cdaR, unrelated to the c-di-AMP PDE genes, serves as a potent negative regulator of c-di-AMP synthesis in this anaerobe. Further, our findings reveal that pdepg and cdaR are required to regulate the incorporation of ATP into c-di-AMP upon pyruvate utilization, leading to enhanced biofilm formation. We show that shifts in c-di-AMP signaling change the integrity and homeostasis of cell envelope, importantly, the structure and immunoreactivity of the lipopolysaccharide layer. Additionally, microbe-microbe interactions and the virulence potential of P. gingivalis were modulated by c-di-AMP. These studies provide the first glimpse into the scheme of second messenger signaling in P. gingivalis and perhaps other Bacteroidetes. Further, our findings indicate that c-di-AMP signaling promotes the fitness of the residents of the oral cavity and the development of a pathogenic community.
Collapse
Affiliation(s)
- M Fata Moradali
- Department of Oral Immunology and Infectious Diseases, University of Louisville, School of Dentistry, Louisville, KY, USA.
| | - Shirin Ghods
- Department of Oral Immunology and Infectious Diseases, University of Louisville, School of Dentistry, Louisville, KY, USA
| | - Heike Bähre
- Research Core Unit Metabolomics, Hannover Medical School, Hanover, Germany
| | - Richard J Lamont
- Department of Oral Immunology and Infectious Diseases, University of Louisville, School of Dentistry, Louisville, KY, USA
| | - David A Scott
- Department of Oral Immunology and Infectious Diseases, University of Louisville, School of Dentistry, Louisville, KY, USA
| | - Roland Seifert
- Research Core Unit Metabolomics, Hannover Medical School, Hanover, Germany
| |
Collapse
|
18
|
Yue H, Miller AL, Khetrapal V, Jayaseker V, Wright S, Du L. Biosynthesis, regulation, and engineering of natural products from Lysobacter. Nat Prod Rep 2022; 39:842-874. [PMID: 35067688 DOI: 10.1039/d1np00063b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Covering: up to August 2021Lysobacter is a genus of Gram-negative bacteria that was classified in 1987. Several Lysobacter species are emerging as new biocontrol agents for crop protection in agriculture. Lysobacter are prolific producers of new bioactive natural products that are largely underexplored. So far, several classes of structurally interesting and biologically active natural products have been isolated from Lysobacter. This article reviews the progress in Lysobacter natural product research over the past ten years, including molecular mechanisms for biosynthesis, regulation and mode of action, genome mining of cryptic biosynthetic gene clusters, and metabolic engineering using synthetic biology tools.
Collapse
Affiliation(s)
- Huan Yue
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Amanda Lynn Miller
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Vimmy Khetrapal
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Vishakha Jayaseker
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Stephen Wright
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| | - Liangcheng Du
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
| |
Collapse
|
19
|
Evolutionary Divergence of the Wsp Signal Transduction Systems in Beta- and Gammaproteobacteria. Appl Environ Microbiol 2021; 87:e0130621. [PMID: 34495711 PMCID: PMC8552884 DOI: 10.1128/aem.01306-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria rapidly adapt to their environment by integrating external stimuli through diverse signal transduction systems. Pseudomonas aeruginosa, for example, senses surface contact through the Wsp signal transduction system to trigger the production of cyclic di-GMP. Diverse mutations in wsp genes that manifest enhanced biofilm formation are frequently reported in clinical isolates of P. aeruginosa and in biofilm studies of Pseudomonas spp. and Burkholderia cenocepacia. In contrast to the convergent phenotypes associated with comparable wsp mutations, we demonstrate that the Wsp system in B. cenocepacia does not impact intracellular cyclic di-GMP levels, unlike that in Pseudomonas spp. Our current mechanistic understanding of the Wsp system is based entirely on the study of four Pseudomonas spp., and its phylogenetic distribution remains unknown. Here, we present a broad phylogenetic analysis to show that the Wsp system originated in the betaproteobacteria and then horizontally transferred to Pseudomonas spp., the sole member of the gammaproteobacteria. Alignment of 794 independent Wsp systems with reported mutations from the literature identified key amino acid residues that fall within and outside annotated functional domains. Specific residues that are highly conserved but uniquely modified in B. cenocepacia likely define mechanistic differences among Wsp systems. We also find the greatest sequence variation in the extracellular sensory domain of WspA, indicating potential adaptations to diverse external stimuli beyond surface contact sensing. This study emphasizes the need to better understand the breadth of functional diversity of the Wsp system as a major regulator of bacterial adaptation beyond B. cenocepacia and select Pseudomonas spp. IMPORTANCE The Wsp signal transduction system serves as an important model system for studying how bacteria adapt to living in densely structured communities known as biofilms. Biofilms frequently cause chronic infections and environmental fouling, and they are very difficult to eradicate. In Pseudomonas aeruginosa, the Wsp system senses contact with a surface, which in turn activates specific genes that promote biofilm formation. We demonstrate that the Wsp system in Burkholderia cenocepacia regulates biofilm formation uniquely from that in Pseudomonas species. Furthermore, a broad phylogenetic analysis reveals the presence of the Wsp system in diverse bacterial species, and sequence analyses of 794 independent systems suggest that the core signaling components function similarly but with key differences that may alter what or how they sense. This study shows that Wsp systems are highly conserved and more broadly distributed than previously thought, and their unique differences likely reflect adaptations to distinct environments.
Collapse
|
20
|
Ishikawa K, Chubachi C, Tochigi S, Hoshi N, Kojima S, Hyodo M, Hayakawa Y, Furuta T, Kera K, Uozumi N. Functional characterization of multiple PAS domain-containing diguanylate cyclases in Synechocystis sp. PCC 6803. MICROBIOLOGY-SGM 2021; 166:659-668. [PMID: 32478657 DOI: 10.1099/mic.0.000929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a second messenger known to control a variety of bacterial processes. The model cyanobacterium, Synechocystis sp. PCC 6803, has a score of genes encoding putative enzymes for c-di-GMP synthesis and degradation. However, most of them have not been functionally characterized. Here, we chose four genes in Synechocystis (dgcA-dgcD), which encode proteins with a GGDEF, diguanylate cyclase (DGC) catalytic domain and multiple Per-ARNT-Sim (PAS) conserved regulatory motifs, for detailed analysis. Purified DgcA, DgcB and DgcC were able to catalyze synthesis of c-di-GMP from two GTPs in vitro. DgcA had the highest activity, compared with DgcB and DgcC. DgcD did not show detectable activity. DgcA activity was specific for GTP and stimulated by the divalent cations, magnesium or manganese. Full activity of DgcA required the presence of the multiple PAS domains, probably because of their role in protein dimerization or stability. Synechocystis mutants carrying single deletions of dgcA-dgcD were not affected in their growth rate or biofilm production during salt stress, suggesting that there was functional redundancy in vivo. In contrast, overexpression of dgcA resulted in increased biofilm formation in the absence of salt stress. In this study, we characterize the enzymatic and physiological function of DgcA-DgcD, and propose that the PAS domains in DgcA function in maintaining the enzyme in its active form.
Collapse
Affiliation(s)
- Ko Ishikawa
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama 6-6-07, Sendai 980-8579, Japan
| | - Chihiro Chubachi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama 6-6-07, Sendai 980-8579, Japan
| | - Saeko Tochigi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama 6-6-07, Sendai 980-8579, Japan
| | - Naomi Hoshi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama 6-6-07, Sendai 980-8579, Japan
| | - Seiji Kojima
- Panasonic corporation, Technology Innovation Division, Hikaridai 3-4, Seika-cho, Soraku-gun, Kyoto 619-0237, Japan
| | - Mamoru Hyodo
- Department of Applied Chemistry, Faculty of Engineering, Aichi Institute of Technology, Toyota 470-0392, Japan
| | - Yoshihiro Hayakawa
- Department of Applied Chemistry, Faculty of Engineering, Aichi Institute of Technology, Toyota 470-0392, Japan
| | - Tadaomi Furuta
- School of Life Science and Technology, Tokyo Institute of Technology, B-62 4259, Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
| | - Kota Kera
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama 6-6-07, Sendai 980-8579, Japan
| | - Nobuyuki Uozumi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aobayama 6-6-07, Sendai 980-8579, Japan
| |
Collapse
|
21
|
O’Malley MR, Anderson JC. Regulation of the Pseudomonas syringae Type III Secretion System by Host Environment Signals. Microorganisms 2021; 9:microorganisms9061227. [PMID: 34198761 PMCID: PMC8228185 DOI: 10.3390/microorganisms9061227] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/30/2021] [Accepted: 06/01/2021] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas syringae are Gram-negative, plant pathogenic bacteria that use a type III secretion system (T3SS) to disarm host immune responses and promote bacterial growth within plant tissues. Despite the critical role for type III secretion in promoting virulence, T3SS-encoding genes are not constitutively expressed by P. syringae and must instead be induced during infection. While it has been known for many years that culturing P. syringae in synthetic minimal media can induce the T3SS, relatively little is known about host signals that regulate the deployment of the T3SS during infection. The recent identification of specific plant-derived amino acids and organic acids that induce T3SS-inducing genes in P. syringae has provided new insights into host sensing mechanisms. This review summarizes current knowledge of the regulatory machinery governing T3SS deployment in P. syringae, including master regulators HrpRS and HrpL encoded within the T3SS pathogenicity island, and the environmental factors that modulate the abundance and/or activity of these key regulators. We highlight putative receptors and regulatory networks involved in linking the perception of host signals to the regulation of the core HrpRS–HrpL pathway. Positive and negative regulation of T3SS deployment is also discussed within the context of P. syringae infection, where contributions from distinct host signals and regulatory networks likely enable the fine-tuning of T3SS deployment within host tissues. Last, we propose future research directions necessary to construct a comprehensive model that (a) links the perception of host metabolite signals to T3SS deployment and (b) places these host–pathogen signaling events in the overall context of P. syringae infection.
Collapse
|
22
|
De Smet J, Wagemans J, Hendrix H, Staes I, Visnapuu A, Horemans B, Aertsen A, Lavigne R. Bacteriophage-mediated interference of the c-di-GMP signalling pathway in Pseudomonas aeruginosa. Microb Biotechnol 2021; 14:967-978. [PMID: 33314648 PMCID: PMC8085984 DOI: 10.1111/1751-7915.13728] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/19/2020] [Accepted: 11/22/2020] [Indexed: 01/10/2023] Open
Abstract
C-di-GMP is a key signalling molecule which impacts bacterial motility and biofilm formation and is formed by the condensation of two GTP molecules by a diguanylate cyclase. We here describe the identification and characterization of a family of bacteriophage-encoded peptides that directly impact c-di-GMP signalling in Pseudomonas aeruginosa. These phage proteins target Pseudomonas diguanylate cyclase YfiN by direct protein interaction (termed YIPs, YfiN Interacting Peptides). YIPs induce an increase of c-di-GMP production in the host cell, resulting in a decrease in motility and an increase in biofilm mass in P. aeruginosa. A dynamic analysis of the biofilm morphology indicates a denser biofilm structure after induction of the phage protein. This intracellular signalling interference strategy by a lytic phage constitutes an unexplored phage-based mechanism of metabolic regulation and could potentially serve as inspiration for the development of molecules that interfere with biofilm formation in P. aeruginosa and other pathogens.
Collapse
Affiliation(s)
- Jeroen De Smet
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
- Present address:
Lab4FoodDepartment of Microbial and Molecular Systems (M2S)KU Leuven Campus GeelGeel2440Belgium
| | - Jeroen Wagemans
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
| | - Hanne Hendrix
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
| | - Ines Staes
- Laboratory of Food MicrobiologyDepartment of Microbial and Molecular SystemsKU LeuvenHeverlee3001Belgium
| | - Annegrete Visnapuu
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
| | - Benjamin Horemans
- Department of Earth and Environmental SciencesKU LeuvenHeverlee3001Belgium
| | - Abram Aertsen
- Laboratory of Food MicrobiologyDepartment of Microbial and Molecular SystemsKU LeuvenHeverlee3001Belgium
| | - Rob Lavigne
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
| |
Collapse
|
23
|
c-di-AMP-Regulated K + Importer KtrAB Affects Biofilm Formation, Stress Response, and SpeB Expression in Streptococcus pyogenes. Infect Immun 2021; 89:IAI.00317-20. [PMID: 33468578 DOI: 10.1128/iai.00317-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 01/14/2021] [Indexed: 11/20/2022] Open
Abstract
The second messenger cyclic di-AMP (c-di-AMP) controls biofilm formation, stress response, and virulence in Streptococcus pyogenes The deletion of the c-di-AMP synthase gene, dacA, results in pleiotropic effects including reduced expression of the secreted protease SpeB. Here, we report a role for K+ transport in c-di-AMP-mediated SpeB expression. The deletion of ktrB in the ΔdacA mutant restores SpeB expression. KtrB is a subunit of the K+ transport system KtrAB that forms a putative high-affinity K+ importer. KtrB forms a membrane K+ channel, and KtrA acts as a cytosolic gating protein that controls the transport capacity of the system by binding ligands including c-di-AMP. SpeB induction in the ΔdacA mutant by K+ specific ionophore treatment also supports the importance of cellular K+ balance in SpeB production. The ΔdacA ΔktrB double deletion mutant not only produces wild-type levels of SpeB but also partially or fully reverts the defective ΔdacA phenotypes of biofilm formation and stress responses, suggesting that many ΔdacA phenotypes are due to cellular K+ imbalance. However, the null pathogenicity of the ΔdacA mutant in a murine subcutaneous infection model is not restored by ktrB deletion, suggesting that c-di-AMP controls not only cellular K+ balance but also other metabolic and/or virulence pathways. The deletion of other putative K+ importer genes, kup and kimA, does not phenocopy the deletion of ktrB regarding SpeB induction in the ΔdacA mutant, suggesting that KtrAB is the primary K+ importer that is responsible for controlling cellular K+ levels under laboratory growth conditions.
Collapse
|
24
|
Loss of Motility as a Non-Lethal Mechanism for Intercolony Inhibition ("Sibling Rivalry") in Marinobacter. Microorganisms 2021; 9:microorganisms9010103. [PMID: 33466273 PMCID: PMC7824750 DOI: 10.3390/microorganisms9010103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/23/2020] [Accepted: 12/30/2020] [Indexed: 11/17/2022] Open
Abstract
Bacteria from the genus Marinobacter are ubiquitous throughout the worlds' oceans as "opportunitrophs" capable of surviving a wide range of conditions, including colonization of surfaces of marine snow and algae. To prevent too many bacteria from occupying this ecological niche simultaneously, some sort of population dependent control must be operative. Here, we show that while Marinobacter do not produce or utilize an acylhomoserine lactone (AHL)-based quorum sensing system, "sibling" colonies of many species of Marinobacter exhibit a form of non-lethal chemical communication that prevents colonies from overrunning each other's niche space. Evidence suggests that this inhibition is the result of a loss in motility for cells at the colony interfaces. Although not the signal itself, we have identified a protein, glycerophosphoryl diester phosphodiesterase, that is enriched in the inhibition zone between the spreading colonies that may be part of the overall response.
Collapse
|
25
|
Xie Y, Liu W, Shao X, Zhang W, Deng X. Signal transduction schemes in Pseudomonas syringae. Comput Struct Biotechnol J 2020; 18:3415-3424. [PMID: 33294136 PMCID: PMC7691447 DOI: 10.1016/j.csbj.2020.10.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/29/2020] [Accepted: 10/31/2020] [Indexed: 11/11/2022] Open
Abstract
To cope with their continually fluctuating surroundings, pathovars of the unicellular phytopathogen Pseudomonas syringae have developed rapid and sophisticated signalling networks to sense extracellular stimuli, which allow them to adjust their cellular composition to survive and cause diseases in host plants. Comparative genomic analyses of P. syringae strains have identified various genes that encode several classes of signalling proteins, although how this bacterium directly perceives these environmental cues remains elusive. Recent work has revealed new mechanisms of a cluster of bacterial signal transduction systems that mainly include two-component systems (such as RhpRS, GacAS, CvsRS and AauRS), extracytoplasmic function sigma factors (such as HrpL and AlgU), nucleotide-based secondary messengers, methyl-accepting chemotaxis sensor proteins and several other intracellular surveillance systems. In this review, we compile a list of the signal transduction mechanisms that P. syringae uses to monitor and respond in a timely manner to intracellular and external conditions. Further understanding of these surveillance processes will provide new perspectives from which to combat P. syringae infections.
Collapse
Affiliation(s)
- Yingpeng Xie
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong 999077, Hong Kong Special Administrative Region
| | - Wenbao Liu
- College of Agricultural Sciences and Technology, Shandong Agriculture and Engineering University, Jinan 250100, China
| | - Xiaolong Shao
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong 999077, Hong Kong Special Administrative Region
| | - Weihua Zhang
- Institute of Vegetables and Flowers, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong 999077, Hong Kong Special Administrative Region.,Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
| |
Collapse
|
26
|
Sanyal R, Harinarayanan R. Activation of RelA by pppGpp as the basis for its differential toxicity over ppGpp in Escherichia coli. J Biosci 2020. [DOI: 10.1007/s12038-020-9991-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
27
|
Poh WH, Lin J, Colley B, Müller N, Goh BC, Schleheck D, El Sahili A, Marquardt A, Liang Y, Kjelleberg S, Lescar J, Rice SA, Klebensberger J. The SiaABC threonine phosphorylation pathway controls biofilm formation in response to carbon availability in Pseudomonas aeruginosa. PLoS One 2020; 15:e0241019. [PMID: 33156827 PMCID: PMC7647112 DOI: 10.1371/journal.pone.0241019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/06/2020] [Indexed: 12/17/2022] Open
Abstract
The critical role of bacterial biofilms in chronic human infections calls for novel anti-biofilm strategies targeting the regulation of biofilm development. However, the regulation of biofilm development is very complex and can include multiple, highly interconnected signal transduction/response pathways, which are incompletely understood. We demonstrated previously that in the opportunistic, human pathogen P. aeruginosa, the PP2C-like protein phosphatase SiaA and the di-guanylate cyclase SiaD control the formation of macroscopic cellular aggregates, a type of suspended biofilms, in response to surfactant stress. In this study, we demonstrate that the SiaABC proteins represent a signal response pathway that functions through a partner switch mechanism to control biofilm formation. We also demonstrate that SiaABCD functionality is dependent on carbon substrate availability for a variety of substrates, and that upon carbon starvation, SiaB mutants show impaired dispersal, in particular with the primary fermentation product ethanol. This suggests that carbon availability is at least one of the key environmental cues integrated by the SiaABCD system. Further, our biochemical, physiological and crystallographic data reveals that the phosphatase SiaA and its kinase counterpart SiaB balance the phosphorylation status of their target protein SiaC at threonine 68 (T68). Crystallographic analysis of the SiaA-PP2C domain shows that SiaA is present as a dimer. Dynamic modelling of SiaA with SiaC suggested that SiaA interacts strongly with phosphorylated SiaC and dissociates rapidly upon dephosphorylation of SiaC. Further, we show that the known phosphatase inhibitor fumonisin inhibits SiaA mediated phosphatase activity in vitro. In conclusion, the present work improves our understanding of how P. aeuruginosa integrates specific environmental conditions, such as carbon availability and surfactant stress, to regulate cellular aggregation and biofilm formation. With the biochemical and structural characterization of SiaA, initial data on the catalytic inhibition of SiaA, and the interaction between SiaA and SiaC, our study identifies promising targets for the development of biofilm-interference drugs to combat infections of this aggressive opportunistic pathogen.
Collapse
Affiliation(s)
- Wee-Han Poh
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jianqing Lin
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research, Singapore, Singapore
| | - Brendan Colley
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Nicolai Müller
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Konstanz, Germany
| | - Boon Chong Goh
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - David Schleheck
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Konstanz, Germany
| | - Abbas El Sahili
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Andreas Marquardt
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Konstanz, Germany
| | - Yang Liang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Julien Lescar
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Scott A. Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- The ithree Institute, The University of Technology Sydney, Sydney, Australia
| | - Janosch Klebensberger
- University of Stuttgart, Institute of Biochemistry and Technical Biochemistry, Stuttgart, Germany
| |
Collapse
|
28
|
Steinchen W, Zegarra V, Bange G. (p)ppGpp: Magic Modulators of Bacterial Physiology and Metabolism. Front Microbiol 2020; 11:2072. [PMID: 33013756 PMCID: PMC7504894 DOI: 10.3389/fmicb.2020.02072] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/06/2020] [Indexed: 01/21/2023] Open
Abstract
When bacteria experience growth-limiting environmental conditions, the synthesis of the hyperphosphorylated guanosine derivatives (p)ppGpp is induced by enzymes of the RelA/SpoT homology (RSH)-type protein family. High levels of (p)ppGpp induce a process called "stringent response", a major cellular reprogramming during which ribosomal RNA (rRNA) and transfer RNA (tRNA) synthesis is downregulated, stress-related genes upregulated, messenger RNA (mRNA) stability and translation altered, and allocation of scarce resources optimized. The (p)ppGpp-mediated stringent response is thus often regarded as an all-or-nothing paradigm induced by stress. Over the past decades, several binding partners of (p)ppGpp have been uncovered displaying dissociation constants from below one micromolar to more than one millimolar and thus coincide with the accepted intracellular concentrations of (p)ppGpp under non-stringent (basal levels) and stringent conditions. This suggests that the ability of (p)ppGpp to modulate target proteins or processes would be better characterized as an unceasing continuum over a concentration range instead of being an abrupt switch of biochemical processes under specific conditions. We analyzed the reported binding affinities of (p)ppGpp targets and depicted a scheme for prioritization of modulation by (p)ppGpp. In this ranking, many enzymes of e.g., nucleotide metabolism are among the first targets to be affected by rising (p)ppGpp while more fundamental processes such as DNA replication are among the last. This preference should be part of (p)ppGpp's "magic" in the adaptation of microorganisms while still maintaining their potential for outgrowth once a stressful condition is overcome.
Collapse
Affiliation(s)
- Wieland Steinchen
- Department of Chemistry, Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | | | - Gert Bange
- Department of Chemistry, Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| |
Collapse
|
29
|
Aline Dias da P, Nathalia Marins de A, Gabriel Guarany de A, Robson Francisco de S, Cristiane Rodrigues G. The World of Cyclic Dinucleotides in Bacterial Behavior. Molecules 2020; 25:molecules25102462. [PMID: 32466317 PMCID: PMC7288161 DOI: 10.3390/molecules25102462] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/05/2020] [Accepted: 03/17/2020] [Indexed: 02/07/2023] Open
Abstract
The regulation of multiple bacterial phenotypes was found to depend on different cyclic dinucleotides (CDNs) that constitute intracellular signaling second messenger systems. Most notably, c-di-GMP, along with proteins related to its synthesis, sensing, and degradation, was identified as playing a central role in the switching from biofilm to planktonic modes of growth. Recently, this research topic has been under expansion, with the discoveries of new CDNs, novel classes of CDN receptors, and the numerous functions regulated by these molecules. In this review, we comprehensively describe the three main bacterial enzymes involved in the synthesis of c-di-GMP, c-di-AMP, and cGAMP focusing on description of their three-dimensional structures and their structural similarities with other protein families, as well as the essential residues for catalysis. The diversity of CDN receptors is described in detail along with the residues important for the interaction with the ligand. Interestingly, genomic data strongly suggest that there is a tendency for bacterial cells to use both c-di-AMP and c-di-GMP signaling networks simultaneously, raising the question of whether there is crosstalk between different signaling systems. In summary, the large amount of sequence and structural data available allows a broad view of the complexity and the importance of these CDNs in the regulation of different bacterial behaviors. Nevertheless, how cells coordinate the different CDN signaling networks to ensure adaptation to changing environmental conditions is still open for much further exploration.
Collapse
|
30
|
Song H, Dharmasena MN, Wang C, Shaw GX, Cherry S, Tropea JE, Jin DJ, Ji X. Structure and activity of PPX/GppA homologs from Escherichia coli and Helicobacter pylori. FEBS J 2020; 287:1865-1885. [PMID: 31679177 PMCID: PMC8189163 DOI: 10.1111/febs.15120] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/22/2019] [Accepted: 11/01/2019] [Indexed: 01/12/2023]
Abstract
Rapid adaptation to environmental changes is crucial for bacterial survival. Almost all bacteria possess a conserved stringent response system to prompt transcriptional and metabolic responses toward stress. The adaptive process relies on alarmones, guanosine pentaphosphate (pppGpp), and tetraphosphate (ppGpp), to regulate global gene expression. The ppGpp is more potent than pppGpp in the regulatory activity, and pppGpp phosphohydrolase (GppA) plays a key role in (p)ppGpp homeostasis. Sharing a similar domain structure, GppA is indistinguishable from exopolyphosphatase (PPX), which mediates the metabolism of cellular inorganic polyphosphate. Here, our phylogenetic analysis of PPX/GppA homologs in bacteria shows a wide distribution with several distinct subfamilies, and our structural and functional analysis of Escherichia coli GppA and Helicobacter pylori PPX/GppA reveals unique properties of each homolog. These results explain how each homolog possesses its distinct functionality.
Collapse
Affiliation(s)
- He Song
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | | | - Chao Wang
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Gary X Shaw
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Scott Cherry
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Joseph E Tropea
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Ding J Jin
- RNA Biology Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Xinhua Ji
- Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| |
Collapse
|
31
|
Schaffert L, Schneiker-Bekel S, Dymek S, Droste J, Persicke M, Busche T, Brandt D, Pühler A, Kalinowski J. Essentiality of the Maltase AmlE in Maltose Utilization and Its Transcriptional Regulation by the Repressor AmlR in the Acarbose-Producing Bacterium Actinoplanes sp. SE50/110. Front Microbiol 2019; 10:2448. [PMID: 31736895 PMCID: PMC6828939 DOI: 10.3389/fmicb.2019.02448] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/11/2019] [Indexed: 11/13/2022] Open
Abstract
Actinoplanes sp. SE50/110 is the wild type of industrial production strains of the fine-chemical acarbose (acarviosyl-maltose), which is used as α-glucosidase inhibitor in the treatment of type II diabetes. Although maltose is an important building block of acarbose, the maltose/maltodextrin metabolism has not been studied in Actinoplanes sp. SE50/110 yet. Bioinformatic analysis located a putative maltase gene amlE (ACSP50_2474, previously named malL; Wendler et al., 2015a), in an operon with an upstream PurR/LacI-type transcriptional regulator gene, named amlR (ACSP50_2475), and a gene downstream (ACSP50_2473) encoding a GGDEF-EAL-domain-containing protein putatively involved in c-di-GMP signaling. Targeted gene deletion mutants of amlE and amlR were constructed by use of the CRISPR/Cas9 technology. By growth experiments and functional assays of ΔamlE, we could show that AmlE is essential for the maltose utilization in Actinoplanes sp. SE50/110. Neither a gene encoding a maltose phosphorylase (MalP) nor MalP enzyme activity were detected in the wild type. By this, the maltose/maltodextrin system appears to be fundamentally different from other described prokaryotic systems. By sequence similarity analysis and functional assays from the species Streptomyces lividans TK23, S. coelicolor A3(2) and S. glaucescens GLA.O, first hints for a widespread lack of MalP and presence of AmlE in the class Actinobacteria were given. Transcription of the aml operon is significantly repressed in the wild type when growing on glucose and repression is absent in an ΔamlR deletion mutant. Although AmlR apparently is a local transcriptional regulator of the aml operon, the ΔamlR strain shows severe growth inhibitions on glucose and – concomitantly – differential transcription of several genes of various functional classes. We ascribe these effects to ACSP50_2473, which is localized downstream of amlE and presumably involved in the metabolism of the second messenger c-di-GMP. It can be assumed, that maltose does not only represent the most important carbon source of Actinoplanes sp. SE50/110, but that its metabolism is coupled to the nucleotide messenger system of c-di-GMP.
Collapse
Affiliation(s)
- Lena Schaffert
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Susanne Schneiker-Bekel
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany.,Senior Research Group in Genome Research of Industrial Microorganisms, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Saskia Dymek
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Julian Droste
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Marcus Persicke
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Tobias Busche
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - David Brandt
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Alfred Pühler
- Senior Research Group in Genome Research of Industrial Microorganisms, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Jörn Kalinowski
- Microbial Genomics and Biotechnology, Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| |
Collapse
|
32
|
Janthinobacterium CG23_2: Comparative Genome Analysis Reveals Enhanced Environmental Sensing and Transcriptional Regulation for Adaptation to Life in an Antarctic Supraglacial Stream. Microorganisms 2019; 7:microorganisms7100454. [PMID: 31618878 PMCID: PMC6843130 DOI: 10.3390/microorganisms7100454] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/12/2019] [Accepted: 10/14/2019] [Indexed: 11/16/2022] Open
Abstract
As many bacteria detected in Antarctic environments are neither true psychrophiles nor endemic species, their proliferation in spite of environmental extremes gives rise to genome adaptations. Janthinobacterium sp. CG23_2 is a bacterial isolate from the Cotton Glacier stream, Antarctica. To understand how Janthinobacterium sp. CG23_2 has adapted to its environment, we investigated its genomic traits in comparison to genomes of 35 published Janthinobacterium species. While we hypothesized that genome shrinkage and specialization to narrow ecological niches would be energetically favorable for dwelling in an ephemeral Antarctic stream, the genome of Janthinobacterium sp. CG23_2 was on average 1.7 ± 0.6 Mb larger and predicted 1411 ± 499 more coding sequences compared to the other Janthinobacterium spp. Putatively identified horizontal gene transfer events contributed 0.92 Mb to the genome size expansion of Janthinobacterium sp. CG23_2. Genes with high copy numbers in the species-specific accessory genome of Janthinobacterium sp. CG23_2 were associated with environmental sensing, locomotion, response and transcriptional regulation, stress response, and mobile elements-functional categories which also showed molecular adaptation to cold. Our data suggest that genome plasticity and the abundant complementary genes for sensing and responding to the extracellular environment supported the adaptation of Janthinobacterium sp. CG23_2 to this extreme environment.
Collapse
|
33
|
Xie Y, Shao X, Deng X. Regulation of type III secretion system inPseudomonas syringae. Environ Microbiol 2019; 21:4465-4477. [DOI: 10.1111/1462-2920.14779] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/10/2019] [Accepted: 08/11/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Yingpeng Xie
- Department of Biomedical SciencesCity University of Hong Kong Kowloon Tong Hong Kong SAR 999077 China
| | - Xiaolong Shao
- Department of Biomedical SciencesCity University of Hong Kong Kowloon Tong Hong Kong SAR 999077 China
| | - Xin Deng
- Department of Biomedical SciencesCity University of Hong Kong Kowloon Tong Hong Kong SAR 999077 China
- Shenzhen Research InstituteCity University of Hong Kong Shenzhen 518057 China
| |
Collapse
|
34
|
Zborníková E, Knejzlík Z, Hauryliuk V, Krásný L, Rejman D. Analysis of nucleotide pools in bacteria using HPLC-MS in HILIC mode. Talanta 2019; 205:120161. [PMID: 31450400 DOI: 10.1016/j.talanta.2019.120161] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/15/2019] [Accepted: 07/17/2019] [Indexed: 01/25/2023]
Abstract
Nucleotides, nucleosides and their derivatives are present in all cells at varying concentrations that change with the nutritional, and energetic status of the cell. Precise measurement of the concentrations of these molecules is instrumental for understanding their regulatory effects. Such measurement is challenging due to the inherent instability of these molecules and, despite many decades of research, the reported values differ widely. Here, we present a comprehensive and easy-to-use approach for determination of the intracellular concentrations of >25 target molecular species. The approach uses rapid filtration and cold acidic extraction followed by high performance liquid chromatography (HPLC) in the hydrophilic interaction liquid chromatography (HILIC) mode using zwitterionic columns coupled with UV and MS detectors. The method reliably detects and quantifies all the analytes expected to be observed in the bacterial cell and paves the way for future studies correlating their concentrations with biological effects.
Collapse
Affiliation(s)
- Eva Zborníková
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovonam. 2, CZ-166 10, Prague 6, Czech Republic; Charles University, Faculty of Science, Department of Analytical Chemistry, Hlavova 8, 128 43, Prague 2, Czech Republic
| | - Zdeněk Knejzlík
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovonam. 2, CZ-166 10, Prague 6, Czech Republic
| | - Vasili Hauryliuk
- Department of Molecular Biology, Umeå University, Building 6K, 6L University Hospital Area, SE-901 87, Umeå, Sweden; Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Building 6K and 6L, University Hospital Area, 90187, Umeå, Sweden; University of Tartu, Institute of Technology, 50411, Tartu, Estonia
| | - Libor Krásný
- Institute of Microbiology, Czech Academy of Sciences v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Dominik Rejman
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovonam. 2, CZ-166 10, Prague 6, Czech Republic.
| |
Collapse
|
35
|
Lassak J, Koller F, Krafczyk R, Volkwein W. Exceptionally versatile – arginine in bacterial post-translational protein modifications. Biol Chem 2019; 400:1397-1427. [DOI: 10.1515/hsz-2019-0182] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/01/2019] [Indexed: 12/24/2022]
Abstract
Abstract
Post-translational modifications (PTM) are the evolutionary solution to challenge and extend the boundaries of genetically predetermined proteomic diversity. As PTMs are highly dynamic, they also hold an enormous regulatory potential. It is therefore not surprising that out of the 20 proteinogenic amino acids, 15 can be post-translationally modified. Even the relatively inert guanidino group of arginine is subject to a multitude of mostly enzyme mediated chemical changes. The resulting alterations can have a major influence on protein function. In this review, we will discuss how bacteria control their cellular processes and develop pathogenicity based on post-translational protein-arginine modifications.
Collapse
Affiliation(s)
- Jürgen Lassak
- Center for Integrated Protein Science Munich (CiPSM), Department of Biology I, Microbiology , Ludwig-Maximilians-Universität München , Grosshaderner Strasse 2-4 , D-82152 Planegg , Germany
| | - Franziska Koller
- Center for Integrated Protein Science Munich (CiPSM), Department of Biology I, Microbiology , Ludwig-Maximilians-Universität München , Grosshaderner Strasse 2-4 , D-82152 Planegg , Germany
| | - Ralph Krafczyk
- Center for Integrated Protein Science Munich (CiPSM), Department of Biology I, Microbiology , Ludwig-Maximilians-Universität München , Grosshaderner Strasse 2-4 , D-82152 Planegg , Germany
| | - Wolfram Volkwein
- Center for Integrated Protein Science Munich (CiPSM), Department of Biology I, Microbiology , Ludwig-Maximilians-Universität München , Grosshaderner Strasse 2-4 , D-82152 Planegg , Germany
| |
Collapse
|
36
|
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.
Collapse
|
37
|
Karunanayake Mudiyanselage APKK, Wu R, Leon-Duque MA, Ren K, You M. "Second-generation" fluorogenic RNA-based sensors. Methods 2019; 161:24-34. [PMID: 30660865 PMCID: PMC6589113 DOI: 10.1016/j.ymeth.2019.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 02/07/2023] Open
Abstract
A fluorogenic aptamer can specifically interact with a fluorophore to activate its fluorescence. These nucleic acid-based fluorogenic modules have been dramatically developed over the past decade, and have been used as versatile reporters in the sensor development and for intracellular imaging. In this review, we summarize the design principles, applications, and challenges of the first-generation fluorogenic RNA-based sensors. Moreover, we discuss some strategies to develop next-generation biosensors with improved sensitivity, selectivity, quantification property, and eukaryotic robustness. Using genetically encoded catalytic hairpin assembly strategy as an example, we further introduce a standard protocol to design, characterize, and apply these fluorogenic RNA-based sensors for in vitro detection and cellular imaging of target biomolecules. By incorporating natural RNA machineries, nucleic acid nanotechnology, and systematic evolution approaches, next-generation fluorogenic RNA-based devices can be potentially engineered to be widely applied in cell biology and biomedicine.
Collapse
Affiliation(s)
| | - Rigumula Wu
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Mark A Leon-Duque
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Kewei Ren
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA
| | - Mingxu You
- Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA.
| |
Collapse
|
38
|
Xu Z, You D, Tang LY, Zhou Y, Ye BC. Metabolic Engineering Strategies Based on Secondary Messengers (p)ppGpp and C-di-GMP To Increase Erythromycin Yield in Saccharopolyspora erythraea. ACS Synth Biol 2019; 8:332-345. [PMID: 30632732 DOI: 10.1021/acssynbio.8b00372] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Secondary messengers (such as (p)ppGpp and c-di-GMP) were proved to play important roles in antibiotic biosynthesis in actinobacteria. In this study, we found that transcription levels of erythromycin-biosynthetic ( ery) genes were upregulated in nutrient limitation, which depended on (p)ppGpp in Saccharopolyspora erythraea. Further study demonstrated that the expression of ery genes and intracellular concentrations of (p)ppGpp showed synchronization during culture process. The erythromycin yield was significantly improved (about 200%) by increasing intracellular concentration of (p)ppGpp through introduction of C-terminally truncated (p)ppGpp synthetase RelA (1.43 kb of the N-terminal segment) from Streptomyces coelicolor into S. erythraea strain NRRL2338 (named as WT/pIB-P BAD- relA1-489). As the intracellular concentration of (p)ppGpp in an industrial erythromycin-high-producing strain E3 was greatly higher (about 10- to 100-fold) than WT strain, the applications of the above-described strategy did not work in E3 strain. Further research revealed that low concentration of 2-oxoglutarate in E3 strain exerted a "nitrogen-rich" pseudosignal, leading to the downregulation of nitrogen metabolism genes, which limited the use of nitrogen sources and thus the high intracellular (p)ppGpp concentration. Furthermore, the secondary messenger, c-di-GMP, was proved to be able to activate ery genes transcription by enhancing binding of BldD to promoters of ery genes. Overexpressing the diguanylate cyclase CdgB from S. coelicolor in S. erythraea increased the intracellular c-di-GMP concentration, and improved erythromycin production. These findings demonstrated that increasing the concentration of intracellular secondary messengers can activate ery genes transcription, and provided new strategies for designing metabolic engineering based on secondary messengers to improve antibiotics yield in actinobacteria.
Collapse
Affiliation(s)
- Zhen Xu
- Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Di You
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Li-Ya Tang
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Ying Zhou
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Bang-Ce Ye
- Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| |
Collapse
|
39
|
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.
Collapse
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.
| |
Collapse
|
40
|
Fontaine BM, Duggal Y, Weinert EE. Exploring the Links between Nucleotide Signaling and Quorum Sensing Pathways in Regulating Bacterial Virulence. ACS Infect Dis 2018; 4:1645-1655. [PMID: 30381948 DOI: 10.1021/acsinfecdis.8b00255] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The survival of all organisms depends on implementation of appropriate phenotypic responses upon perception of relevant environmental stimuli. Sensory inputs are propagated via interconnected biochemical and/or electrical cascades mediated by diverse signaling molecules, including gases, metal cations, lipids, peptides, and nucleotides. These networks often comprise second messenger signaling systems in which a ligand (the primary messenger) binds to an extracellular receptor, thereby altering the intracellular concentration of a second messenger molecule which ultimately modulates gene expression through interaction with various effectors. The identification of intersections of these signaling pathways, such as nucleotide second messengers and quorum sensing, provides new insights into the mechanisms by which bacteria use multiple inputs to regulate cellular metabolism and phenotypes. Further investigations of the overlap between bacterial signaling pathways may yield new targets and methods to control bacterial behavior, such as biofilm formation and virulence.
Collapse
Affiliation(s)
- Benjamin M. Fontaine
- Department of Chemistry, Emory University, 1515 Dickey Drive NE, Atlanta, Georgia 30322, United States
| | - Yashasvika Duggal
- Department of Chemistry, Emory University, 1515 Dickey Drive NE, Atlanta, Georgia 30322, United States
| | - Emily E. Weinert
- Department of Chemistry, Emory University, 1515 Dickey Drive NE, Atlanta, Georgia 30322, United States
| |
Collapse
|
41
|
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.
Collapse
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
| |
Collapse
|
42
|
Drecktrah D, Hall LS, Rescheneder P, Lybecker M, Samuels DS. The Stringent Response-Regulated sRNA Transcriptome of Borrelia burgdorferi. Front Cell Infect Microbiol 2018; 8:231. [PMID: 30027068 PMCID: PMC6041397 DOI: 10.3389/fcimb.2018.00231] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/19/2018] [Indexed: 12/12/2022] Open
Abstract
The Lyme disease spirochete Borrelia (Borreliella) burgdorferi must tolerate nutrient stress to persist in the tick phase of its enzootic life cycle. We previously found that the stringent response mediated by RelBbu globally regulates gene expression to facilitate persistence in the tick vector. Here, we show that RelBbu regulates the expression of a swath of small RNAs (sRNA), affecting 36% of previously identified sRNAs in B. burgdorferi. This is the first sRNA regulatory mechanism identified in any spirochete. Threefold more sRNAs were RelBbu-upregulated than downregulated during nutrient stress and included antisense, intergenic and 5′ untranslated region sRNAs. RelBbu-regulated sRNAs associated with genes known to be important for host infection (bosR and dhhp) as well as persistence in the tick (glpF and hk1) were identified, suggesting potential mechanisms for post-transcriptional regulation of gene expression.
Collapse
Affiliation(s)
- Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Laura S Hall
- Division of Biological Sciences, University of Montana, Missoula, MT, United States
| | - Philipp Rescheneder
- Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Meghan Lybecker
- Department of Biology, University of Colorado, Colorado Springs, CO, United States
| | - D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT, United States.,Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT, United States
| |
Collapse
|
43
|
Wang Q, Ji F, Guo J, Wang Y, Li Y, Wang J, An L, Bao Y. LotS/LotR/Clp, a novel signal pathway responding to temperature, modulating protease expression via c-di-GMP mediated manner in Stenotrophomonas maltophilia FF11. Microbiol Res 2018; 214:60-73. [PMID: 30031482 DOI: 10.1016/j.micres.2018.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/30/2018] [Accepted: 05/17/2018] [Indexed: 11/25/2022]
Abstract
Stenotrophomonas maltophilia as one of increasing food spoilage bacteria and fish pathogens has become a threat to aquiculture industry. A major factor contributing to the success of bacterium is its outstanding ability to secrete protease at low temperatures. Here, a cAMP receptor like protein (Clp) shows a positive regulation on this protease, named S. maltophilia temperature-response protease (SmtP). Interestingly, a two-component system, comprising of LotS sensor and LotR regulator, for low-temperature response is also confirmed to modulate SmtP expression with similar effect to Clp. Evidence is presented that LotS/LotR modulates smtP (coding SmtP) expression via Clp: clp promoter activity was reduced significantly at low temperatures and protease activity was partially restored by Clp overexpressed in lotS or lotR deletion strain. Furthermore, as a Clp negative effector, the binding ability of c-di-GMP with Clp is not impacted by temperature. c-di-GMP level was increased in S. maltophilia growing at high temperature, but not exhibited significantly in lotR deleted strain, these indicate that LotR is required for temperature modulating c-di-GMP level, although the synthesis or degradation activity of c-di-GMP by LotR was not detected. These findings suggest that LotS/LotR/Clp play an important role in responding to temperature stimuli via c-di-GMP mediated manner.
Collapse
Affiliation(s)
- Qingling Wang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Fangling Ji
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Jianli Guo
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Yuepeng Wang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Yanyan Li
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Jingyun Wang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Lijia An
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Yongming Bao
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China; School of Food and Environment Science and Technology, Dalian University of Technology, Panjin, 124221, China.
| |
Collapse
|
44
|
Bähre H, Kaever V. Identification and Quantification of Cyclic Di-Guanosine Monophosphate and Its Linear Metabolites by Reversed-Phase LC-MS/MS. Methods Mol Biol 2018; 1657:45-58. [PMID: 28889285 DOI: 10.1007/978-1-4939-7240-1_5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cyclic dinucleotides such as bis-(3',5')-cyclic dimeric guanosine monophosphate (3',3'-c-di-GMP) represent an important class of second messengers in bacteria and are involved in numerous (patho)physiological settings. Here, we describe a sensitive and specific quantification method for 3',3'-c-di-GMP by HPLC-coupled tandem mass spectrometry (LC-MS/MS). Additionally, linear 3',3'-c-di-GMP metabolites, i.e., 5'-phosphoguanylyl-3',5'-guanosine (pGpG) and 5'-guanosine monophosphate (5'-GMP), as well as cyclic guanosine monophosphate (3',5'-cGMP) and 3',3' c-di-GMP analogues (2',3'-c-di-GMP and 2',2'-c-di-GMP) can be simultaneously determined by this method.
Collapse
Affiliation(s)
- Heike Bähre
- Research Core Unit Metabolomics, Institute of Pharmacology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Volkhard Kaever
- Research Core Unit Metabolomics, Institute of Pharmacology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| |
Collapse
|
45
|
Koonin EV, Makarova KS. Discovery of Oligonucleotide Signaling Mediated by CRISPR-Associated Polymerases Solves Two Puzzles but Leaves an Enigma. ACS Chem Biol 2018; 13:309-312. [PMID: 28937734 PMCID: PMC11075118 DOI: 10.1021/acschembio.7b00713] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The signature component of type III CRISPR-Cas systems is the Cas10 protein that consists of two Palm domains homologous to those of DNA and RNA polymerases and nucleotide cyclases and an HD nuclease domain. However, until very recently, the activity of the Palm domains and their role in CRISPR function have not been experimentally established. Most of the type III CRISPR-Cas systems and some type I systems also encompass proteins containing the CARF (CRISPR-associated Rossmann fold) domain that has been predicted to regulate CRISPR functions via nucleotide binding, but its function in CRISPR-Cas remained obscure. Two independent recent studies show that the Palm domain of Cas10 catalyzes synthesis of oligoadenylates, which bind the CARF domain of the Csm6 protein and activate its RNase domain that cleaves foreign transcripts enabling interference by type III CRISPR-Cas. In one coup, these findings resolved two long-standing puzzles of CRISPR biology and reveal a new regulatory pathway that governs the CRISPR response. However, the full extent of this pathway, and especially the driving forces behind the evolution of this complex mechanism of CRISPR-Cas activation, remains to be uncovered.
Collapse
Affiliation(s)
- Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, Maryland 20894, United States
| | - Kira S. Makarova
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, Maryland 20894, United States
| |
Collapse
|
46
|
Wilde A, Mullineaux CW. Light-controlled motility in prokaryotes and the problem of directional light perception. FEMS Microbiol Rev 2017; 41:900-922. [PMID: 29077840 PMCID: PMC5812497 DOI: 10.1093/femsre/fux045] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/12/2017] [Indexed: 12/02/2022] Open
Abstract
The natural light environment is important to many prokaryotes. Most obviously, phototrophic prokaryotes need to acclimate their photosynthetic apparatus to the prevailing light conditions, and such acclimation is frequently complemented by motility to enable cells to relocate in search of more favorable illumination conditions. Non-phototrophic prokaryotes may also seek to avoid light at damaging intensities and wavelengths, and many prokaryotes with diverse lifestyles could potentially exploit light signals as a rich source of information about their surroundings and a cue for acclimation and behavior. Here we discuss our current understanding of the ways in which bacteria can perceive the intensity, wavelength and direction of illumination, and the signal transduction networks that link light perception to the control of motile behavior. We discuss the problems of light perception at the prokaryotic scale, and the challenge of directional light perception in small bacterial cells. We explain the peculiarities and the common features of light-controlled motility systems in prokaryotes as diverse as cyanobacteria, purple photosynthetic bacteria, chemoheterotrophic bacteria and haloarchaea.
Collapse
Affiliation(s)
- Annegret Wilde
- Institute of Biology III, University of Freiburg, 79104 Freiburg, Germany
- BIOSS Centre of Biological Signalling Studies, University of Freiburg, 79106 Freiburg, Germany
| | - Conrad W. Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| |
Collapse
|
47
|
Mankan AK, Müller M, Witte G, Hornung V. Cyclic Dinucleotides in the Scope of the Mammalian Immune System. Handb Exp Pharmacol 2017; 238:269-289. [PMID: 28181006 DOI: 10.1007/164_2016_5002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
First discovered in prokaryotes and more recently in eukaryotes, cyclic dinucleotides (CDNs) constitute a unique branch of second messenger signaling systems. Within prokaryotes CDNs regulate a wide array of different biological processes, whereas in the vertebrate system CDN signaling is largely dedicated to activation of the innate immune system. In this book chapter we summarize the occurrence and signaling pathways of these small-molecule second messengers, most importantly in the scope of the mammalian immune system. In this regard, our main focus is the role of the cGAS-STING axis in the context of microbial infection and sterile inflammation and its implications for therapeutic applications.
Collapse
Affiliation(s)
- Arun K Mankan
- Institute of Molecular Medicine, University Hospital, University of Bonn, Sigmund-Freud-Str. 25, Bonn, 53127, Germany
| | - Martina Müller
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, Munich, 81377, Germany
| | - Gregor Witte
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, Munich, 81377, Germany
| | - Veit Hornung
- Institute of Molecular Medicine, University Hospital, University of Bonn, Sigmund-Freud-Str. 25, Bonn, 53127, Germany. .,Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, Munich, 81377, Germany. .,Center for Integrated Protein Science (CIPSM), Ludwig-Maximilians-Universitðt Mﺰnchen, Feodor-Lynen-Str. 25, 81377, Munich, Germany.
| |
Collapse
|
48
|
Hauryliuk V, Atkinson GC. Small Alarmone Synthetases as novel bacterial RNA-binding proteins. RNA Biol 2017; 14:1695-1699. [PMID: 28820325 DOI: 10.1080/15476286.2017.1367889] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
The alarmone nucleotides guanosine pentaphosphate (pppGpp) and tetraphosphate (ppGpp), collectively referred to as (p)ppGpp, are key regulators of bacterial growth, stress adaptation, antibiotic tolerance and pathogenicity. We have recently shown that the Small Alarmone Synthetase (SAS) RelQ from the Gram-positive pathogen Enterococcus faecalis has an RNA-binding activity (Beljantseva et al. 2017). RelQ's activities as an enzyme and as an RNA-binding protein are mutually incompatible: binding of single-stranded RNA potently inhibits (p)ppGpp synthesis in a sequence-specific manner, and RelQ's enzymatic activity destabilizes the RNA:RelQ complex. RelQ's allosteric regulator, pppGpp, destabilizes RNA binding and activates RelQ's enzymatic activity. Since SAS enzymes are widely distributed in bacteria, and, as has been discovered recently, are also mobilized by phages (Dedrick et al. 2017), RNA binding to SASs could be a widespread mechanism. The initial discovery raises numerous questions regarding RNA-binding function of the SAS enzymes: What is the molecular mechanism underlying the incompatibility of RNA:SAS complex formation with pppGpp binding and (p)ppGpp synthesis? What are the RNA targets in living cells? What is the regulatory output of the system - (p)ppGpp synthesis, modulation of RNA structure and function, or both?
Collapse
Affiliation(s)
- Vasili Hauryliuk
- a Department of Molecular Biology , Umeå University , 6L University Hospital Area, Umeå , Sweden.,b Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, University Hospital Area , Umeå , Sweden.,c University of Tartu, Institute of Technology , Tartu , Estonia
| | - Gemma C Atkinson
- a Department of Molecular Biology , Umeå University , 6L University Hospital Area, Umeå , Sweden
| |
Collapse
|
49
|
HPLC-based quantification of bacterial housekeeping nucleotides and alarmone messengers ppGpp and pppGpp. Sci Rep 2017; 7:11022. [PMID: 28887466 PMCID: PMC5591245 DOI: 10.1038/s41598-017-10988-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/17/2017] [Indexed: 02/02/2023] Open
Abstract
Here we describe an HPLC-based method to quantify bacterial housekeeping nucleotides and the signaling messengers ppGpp and pppGpp. We have replicated and tested several previously reported HPLC-based approaches and assembled a method that can process 50 samples in three days, thus making kinetically resolved experiments feasible. The method combines cell harvesting by rapid filtration, followed by acid extraction, freeze-drying with chromatographic separation. We use a combination of C18 IPRP-HPLC (GMP unresolved and co-migrating with IMP; GDP and GTP; AMP, ADP and ATP; CTP; UTP) and SAX-HPLC in isocratic mode (ppGpp and pppGpp) with UV detection. The approach is applicable to bacteria without the requirement of metabolic labelling with 32P-labelled radioactive precursors. We applied our method to quantify nucleotide pools in Escherichia coli BW25113 K12-strain both throughout the growth curve and during acute stringent response induced by mupirocin. While ppGpp and pppGpp levels vary drastically (40- and ≥8-fold, respectively) these changes are decoupled from the quotients of the housekeeping pool and guanosine and adenosine housekeeping nucleotides: NTP/NDP/NMP ratio remains stable at 6/1/0.3 during both normal batch culture growth and upon acute amino acid starvation.
Collapse
|
50
|
Fahmi T, Port GC, Cho KH. c-di-AMP: An Essential Molecule in the Signaling Pathways that Regulate the Viability and Virulence of Gram-Positive Bacteria. Genes (Basel) 2017; 8:E197. [PMID: 28783096 PMCID: PMC5575661 DOI: 10.3390/genes8080197] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 07/29/2017] [Accepted: 07/31/2017] [Indexed: 11/16/2022] Open
Abstract
Signal transduction pathways enable organisms to monitor their external environment and adjust gene regulation to appropriately modify their cellular processes. Second messenger nucleotides including cyclic adenosine monophosphate (c-AMP), cyclic guanosine monophosphate (c-GMP), cyclic di-guanosine monophosphate (c-di-GMP), and cyclic di-adenosine monophosphate (c-di-AMP) play key roles in many signal transduction pathways used by prokaryotes and/or eukaryotes. Among the various second messenger nucleotides molecules, c-di-AMP was discovered recently and has since been shown to be involved in cell growth, survival, and regulation of virulence, primarily within Gram-positive bacteria. The cellular level of c-di-AMP is maintained by a family of c-di-AMP synthesizing enzymes, diadenylate cyclases (DACs), and degradation enzymes, phosphodiesterases (PDEs). Genetic manipulation of DACs and PDEs have demonstrated that alteration of c-di-AMP levels impacts both growth and virulence of microorganisms. Unlike other second messenger molecules, c-di-AMP is essential for growth in several bacterial species as many basic cellular functions are regulated by c-di-AMP including cell wall maintenance, potassium ion homeostasis, DNA damage repair, etc. c-di-AMP follows a typical second messenger signaling pathway, beginning with binding to receptor molecules to subsequent regulation of downstream cellular processes. While c-di-AMP binds to specific proteins that regulate pathways in bacterial cells, c-di-AMP also binds to regulatory RNA molecules that control potassium ion channel expression in Bacillus subtilis. c-di-AMP signaling also occurs in eukaryotes, as bacterially produced c-di-AMP stimulates host immune responses during infection through binding of innate immune surveillance proteins. Due to its existence in diverse microorganisms, its involvement in crucial cellular activities, and its stimulating activity in host immune responses, c-di-AMP signaling pathway has become an attractive antimicrobial drug target and therefore has been the focus of intensive study in several important pathogens.
Collapse
Affiliation(s)
- Tazin Fahmi
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| | - Gary C Port
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO 63110, USA.
- Elanco Animal Health, Natural Products Fermentation, Eli Lilly and Company, Indianapolis, IN 46285, USA.
| | - Kyu Hong Cho
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| |
Collapse
|