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Liu L, Luo D, Zhang Y, Liu D, Yin K, Tang Q, Chou SH, He J. Characterization of the dual regulation by a c-di-GMP riboswitch Bc1 with a long expression platform from Bacillus thuringiensis. Microbiol Spectr 2024; 12:e0045024. [PMID: 38819160 DOI: 10.1128/spectrum.00450-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 04/29/2024] [Indexed: 06/01/2024] Open
Abstract
A riboswitch generally regulates the expression of its downstream genes through conformational change in its expression platform (EP) upon ligand binding. The cyclic diguanosine monophosphate (c-di-GMP) class I riboswitch Bc1 is widespread and conserved among Bacillus cereus group species. In this study, we revealed that Bc1 has a long EP with two typical ρ-independent terminator sequences 28 bp apart. The upstream terminator T1 is dominant in vitro, while downstream terminator T2 is more efficient in vivo. Through mutation analysis, we elucidated that Bc1 exerts a rare and incoherent "transcription-translation" dual regulation with T2 playing a crucial role. However, we found that Bc1 did not respond to c-di-GMP under in vitro transcription conditions, and the expressions of downstream genes did not change with fluctuation in intracellular c-di-GMP concentration. To explore this puzzle, we conducted SHAPE-MaP and confirmed the interaction of Bc1 with c-di-GMP. This shows that as c-di-GMP concentration increases, T1 unfolds but T2 remains almost intact and functional. The presence of T2 masks the effect of T1 unwinding, resulting in no response of Bc1 to c-di-GMP. The high Shannon entropy values of EP region imply the potential alternative structures of Bc1. We also found that zinc uptake regulator can specifically bind to the dual terminator coding sequence and slightly trigger the response of Bc1 to c-di-GMP. This work will shed light on the dual-regulation riboswitch and enrich our understanding of the RNA world.IMPORTANCEIn nature, riboswitches are involved in a variety of metabolic regulation, most of which preferentially regulate transcription termination or translation initiation of downstream genes in specific ways. Alternatively, the same or different riboswitches can exist in tandem to enhance regulatory effects or respond to multiple ligands. However, many putative conserved riboswitches have not yet been experimentally validated. Here, we found that the c-di-GMP riboswitch Bc1 with a long EP could form a dual terminator and exhibit non-canonical and incoherent "transcription-translation" dual regulation. Besides, zinc uptake regulator specifically bound to the coding sequence of the Bc1 EP and slightly mediated the action of Bc1. The application of SHAPE-MaP to the dual regulation mechanism of Bc1 may establish the foundation for future studies of such complex untranslated regions in other bacterial genomes.
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Affiliation(s)
- Lu Liu
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Dehua Luo
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yongji Zhang
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Dingqi Liu
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Kang Yin
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Qing Tang
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shan-Ho Chou
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jin He
- National Key Laboratory of Agricultural Microbiology & Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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2
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Geiger CJ, Wong GCL, O'Toole GA. A bacterial sense of touch: T4P retraction motor as a means of surface sensing by Pseudomonas aeruginosa PA14. J Bacteriol 2024:e0044223. [PMID: 38832786 DOI: 10.1128/jb.00442-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Abstract
Most microbial cells found in nature exist in matrix-covered, surface-attached communities known as biofilms. This mode of growth is initiated by the ability of the microbe to sense a surface on which to grow. The opportunistic pathogen Pseudomonas aeruginosa (Pa) PA14 utilizes a single polar flagellum and type 4 pili (T4P) to sense surfaces. For Pa, T4P-dependent "twitching" motility is characterized by effectively pulling the cell across a surface through a complex process of cooperative binding, pulling, and unbinding. T4P retraction is powered by hexameric ATPases. Pa cells that have engaged a surface increase production of the second messenger cyclic AMP (cAMP) over multiple generations via the Pil-Chp system. This rise in cAMP allows cells and their progeny to become better adapted for surface attachment and activates virulence pathways through the cAMP-binding transcription factor Vfr. While many studies have focused on mechanisms of T4P twitching and regulation of T4P production and function by the Pil-Chp system, the mechanism by which Pa senses and relays a surface-engagement signal to the cell is still an open question. Here we review the current state of the surface sensing literature for Pa, with a focus on T4P, and propose an integrated model of surface sensing whereby the retraction motor PilT senses and relays the signal to the Pil-Chp system via PilJ to drive cAMP production and adaptation to a surface lifestyle.
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Affiliation(s)
- C J Geiger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - G C L Wong
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - G A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Liu C, Shi R, Jensen MS, Zhu J, Liu J, Liu X, Sun D, Liu W. The global regulation of c-di-GMP and cAMP in bacteria. MLIFE 2024; 3:42-56. [PMID: 38827514 PMCID: PMC11139211 DOI: 10.1002/mlf2.12104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/16/2023] [Accepted: 10/09/2023] [Indexed: 06/04/2024]
Abstract
Nucleotide second messengers are highly versatile signaling molecules that regulate a variety of key biological processes in bacteria. The best-studied examples are cyclic AMP (cAMP) and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), which both act as global regulators. Global regulatory frameworks of c-di-GMP and cAMP in bacteria show several parallels but also significant variances. In this review, we illustrate the global regulatory models of the two nucleotide second messengers, compare the different regulatory frameworks between c-di-GMP and cAMP, and discuss the mechanisms and physiological significance of cross-regulation between c-di-GMP and cAMP. c-di-GMP responds to numerous signals dependent on a great number of metabolic enzymes, and it regulates various signal transduction pathways through its huge number of effectors with varying activities. In contrast, due to the limited quantity, the cAMP metabolic enzymes and its major effector are regulated at different levels by diverse signals. cAMP performs its global regulatory function primarily by controlling the transcription of a large number of genes via cAMP receptor protein (CRP) in most bacteria. This review can help us understand how bacteria use the two typical nucleotide second messengers to effectively coordinate and integrate various physiological processes, providing theoretical guidelines for future research.
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Affiliation(s)
- Cong Liu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Rui Shi
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Marcus S. Jensen
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Jingrong Zhu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Jiawen Liu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Xiaobo Liu
- Key Laboratory of Metabolic Engineering and Biosynthesis Technology, Ministry of Industry and Information TechnologyNanjing University of Science and TechnologyNanjingChina
| | - Di Sun
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
| | - Weijie Liu
- Jiangsu Key Laboratory of Phylogenomics & Comparative Genomics, School of Life SciencesJiangsu Normal UniversityXuzhouChina
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4
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Feng Q, Zhou J, Zhang L, Fu Y, Yang L. Insights into the molecular basis of c-di-GMP signalling in Pseudomonas aeruginosa. Crit Rev Microbiol 2024; 50:20-38. [PMID: 36539391 DOI: 10.1080/1040841x.2022.2154140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/25/2022] [Indexed: 12/24/2022]
Abstract
The opportunistic human pathogen Pseudomonas aeruginosa can cause severe infections in immunocompromized people or cystic fibrosis (CF) patients. Because of its remarkable ability to invade the host and withstand the bacteriocidal effect of most conventional antibiotics, the infection caused by P. aeruginosa has become a major concern for human health. The switch from acute to chronic infection is governed by the second messenger bis-(3'-5')-cyclic dimeric guanosine mono-phosphate (c-di-GMP) in P. aeruginosa, and c-di-GMP is now recognized to regulate many important biological processes in pathogenesis. The c-di-GMP signalling mechanisms in P. aeruginosa have been studied extensively in the past decade, revealing complicated c-di-GMP metabolism and signalling network. In this review, the underlying mechanisms of this signalling network will be discussed, mainly focussing on how environmental cues regulate c-di-GMP signalling, protein-protein interaction mediated functional regulation, heterogeneity of c-di-GMP and cross talk between c-di-GMP signalling and other signalling systems. Understanding the molecular mechanism underlying the complex c-di-GMP signalling network would be beneficial for developing therapeutic approaches and antibacterial agents to combat the threat from P. aeruginosa.
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Affiliation(s)
- Qishun Feng
- School of Medicine, Southern University of Science and Technology, Shenzhen, PR China
| | - Jianuan Zhou
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, PR China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, PR China
| | - Lianhui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, PR China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, PR China
| | - Yang Fu
- School of Medicine, Southern University of Science and Technology, Shenzhen, PR China
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, Shenzhen, PR China
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5
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Khan F, Jeong GJ, Tabassum N, Kim YM. Functional diversity of c-di-GMP receptors in prokaryotic and eukaryotic systems. Cell Commun Signal 2023; 21:259. [PMID: 37749602 PMCID: PMC10519070 DOI: 10.1186/s12964-023-01263-5] [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: 06/21/2023] [Accepted: 08/09/2023] [Indexed: 09/27/2023] Open
Abstract
Cyclic bis-(3', 5')-dimeric guanosine monophosphate (c-di-GMP) is ubiquitous in many bacterial species, where it functions as a nucleotide-based secondary messenger and is a vital regulator of numerous biological processes. Due to its ubiquity, most bacterial species possess a wide range of downstream receptors that has a binding affinity to c-di-GMP and elicit output responses. In eukaryotes, several enzymes and riboswitches operate as receptors that interact with c-di-GMP and transduce cellular or environmental signals. This review examines the functional variety of receptors in prokaryotic and eukaryotic systems that exhibit distinct biological responses after interacting with c-di-GMP. Evolutionary relationships and similarities in distance among the c-di-GMP receptors in various bacterial species were evaluated to understand their specificities. Furthermore, residues of receptors involved in c-di-GMP binding are summarized. This review facilitates the understanding of how distinct receptors from different origins bind c-di-GMP equally well, yet fulfill diverse biological roles at the interspecies, intraspecies, and interkingdom levels. Furthermore, it also highlights c-di-GMP receptors as potential therapeutic targets, particularly those found in pathogenic microorganisms. Video Abstract.
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Affiliation(s)
- Fazlurrahman Khan
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea.
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea.
| | - Geum-Jae Jeong
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Nazia Tabassum
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea
| | - Young-Mog Kim
- Marine Integrated Biomedical Technology Center, The National Key Research Institutes in Universities, Pukyong National University, Busan, 48513, Republic of Korea.
- Research Center for Marine Integrated Bionics Technology, Pukyong National University, Busan, 48513, Republic of Korea.
- Department of Food Science and Technology, Pukyong National University, Busan, 48513, Republic of Korea.
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6
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Geiger CJ, O’Toole GA. Evidence for the Type IV Pilus Retraction Motor PilT as a Component of the Surface Sensing System in Pseudomonas aeruginosa. J Bacteriol 2023; 205:e0017923. [PMID: 37382531 PMCID: PMC10367593 DOI: 10.1128/jb.00179-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/30/2023] Open
Abstract
Biofilm formation begins when bacteria contacting a surface induce cellular changes to become better adapted for surface growth. One of the first changes to occur for Pseudomonas aeruginosa after surface contact is an increase in the nucleotide second messenger 3',5'-cyclic AMP (cAMP). It has been demonstrated that this increase in intracellular cAMP is dependent on functional type IV pili (T4P) relaying a signal to the Pil-Chp system, but the mechanism by which this signal is transduced remains poorly understood. Here, we investigate the role of the type IV pilus retraction motor PilT in sensing a surface and relaying that signal to cAMP production. We show that mutations in PilT, and in particular those impacting the ATPase activity of this motor protein, reduce surface-dependent cAMP production. We identify a novel interaction between PilT and PilJ, a member of the Pil-Chp system, and propose a new model whereby P. aeruginosa uses its PilT retraction motor to sense a surface and to relay that signal via PilJ to increased production of cAMP. We discuss these findings in light of current T4P-dependent surface sensing models for P. aeruginosa. IMPORTANCE T4P are cellular appendages that allow P. aeruginosa to sense a surface, leading to the production of cAMP. This second messenger not only activates virulence pathways but leads to further surface adaptation and irreversible attachment of cells. Here, we demonstrate the importance of the retraction motor PilT in surface sensing. We also present a new surface sensing model in P. aeruginosa whereby the T4P retraction motor PilT senses and transmits the surface signal, likely via its ATPase domain and interaction with PilJ, to mediate production of the second messenger cAMP.
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Affiliation(s)
- C. J. Geiger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - G. A. O’Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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7
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Scherhag A, Räschle M, Unbehend N, Venn B, Glueck D, Mühlhaus T, Keller S, Pérez Patallo E, Zehner S, Frankenberg-Dinkel N. Characterization of a soluble library of the Pseudomonas aeruginosa PAO1 membrane proteome with emphasis on c-di-GMP turnover enzymes. MICROLIFE 2023; 4:uqad028. [PMID: 37441524 PMCID: PMC10335732 DOI: 10.1093/femsml/uqad028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/28/2023] [Accepted: 05/30/2023] [Indexed: 07/15/2023]
Abstract
Studies of protein-protein interactions in membranes are very important to fully understand the biological function of a cell. The extraction of proteins from the native membrane environment is a critical step in the preparation of membrane proteins that might affect the stability of protein complexes. In this work, we used the amphiphilic diisobutylene/maleic acid copolymer to extract the membrane proteome of the opportunistic pathogen Pseudomonas aeruginosa, thereby creating a soluble membrane-protein library within a native-like lipid-bilayer environment. Size fractionation of nanodisc-embedded proteins and subsequent mass spectrometry enabled the identification of 3358 proteins. The native membrane-protein library showed a very good overall coverage compared to previous proteome data. The pattern of size fractionation indicated that protein complexes were preserved in the library. More than 20 previously described complexes, e.g. the SecYEG and Pili complexes, were identified and analyzed for coelution. Although the mass-spectrometric dataset alone did not reveal new protein complexes, combining pulldown assays with mass spectrometry was successful in identifying new protein interactions in the native membrane-protein library. Thus, we identified several candidate proteins for interactions with the membrane phosphodiesterase NbdA, a member of the c-di-GMP network. We confirmed the candidate proteins CzcR, PA4200, SadC, and PilB as novel interaction partners of NbdA using the bacterial adenylate cyclase two-hybrid assay. Taken together, this work demonstrates the usefulness of the native membrane-protein library of P. aeruginosa for the investigation of protein interactions and membrane-protein complexes. Data are available via ProteomeXchange with identifiers PXD039702 and PXD039700.
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Affiliation(s)
- Anna Scherhag
- Department of Microbiology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - Markus Räschle
- Department of Molecular Genetics, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - Niklas Unbehend
- Department of Microbiology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - Benedikt Venn
- Department of Computational Systems Biology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - David Glueck
- Department of Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Graz 8010, Austria
- Department of Field of Excellence BioHealth, University of Graz, Graz 8010, Austria
- BioTechMed-Graz, Graz 8010, Austria
| | - Timo Mühlhaus
- Department of Computational Systems Biology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | - Sandro Keller
- Department of Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Graz 8010, Austria
- Department of Field of Excellence BioHealth, University of Graz, Graz 8010, Austria
- BioTechMed-Graz, Graz 8010, Austria
| | - Eugenio Pérez Patallo
- Department of Microbiology, RPTU Kaiserslautern-Landau, Kaiserslautern 67655, Germany
| | | | - Nicole Frankenberg-Dinkel
- Corresponding author. RPTU Kaiserslautern-Landau, Microbiology, Kaiserslautern 67655, Germany. E-mail:
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8
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Kühn MJ, Macmillan H, Talà L, Inclan Y, Patino R, Pierrat X, Al‐Mayyah Z, Engel JN, Persat A. Two antagonistic response regulators control Pseudomonas aeruginosa polarization during mechanotaxis. EMBO J 2023; 42:e112165. [PMID: 36795017 PMCID: PMC10519157 DOI: 10.15252/embj.2022112165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 02/17/2023] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa adapts to solid surfaces to enhance virulence and infect its host. Type IV pili (T4P), long and thin filaments that power surface-specific twitching motility, allow single cells to sense surfaces and control their direction of movement. T4P distribution is polarized to the sensing pole by the chemotaxis-like Chp system via a local positive feedback loop. However, how the initial spatially resolved mechanical signal is translated into T4P polarity is incompletely understood. Here, we demonstrate that the two Chp response regulators PilG and PilH enable dynamic cell polarization by antagonistically regulating T4P extension. By precisely quantifying the localization of fluorescent protein fusions, we show that phosphorylation of PilG by the histidine kinase ChpA controls PilG polarization. Although PilH is not strictly required for twitching reversals, it becomes activated upon phosphorylation and breaks the local positive feedback mechanism established by PilG, allowing forward-twitching cells to reverse. Chp thus uses a main output response regulator, PilG, to resolve mechanical signals in space and employs a second regulator, PilH, to break and respond when the signal changes. By identifying the molecular functions of two response regulators that dynamically control cell polarization, our work provides a rationale for the diversity of architectures often found in non-canonical chemotaxis systems.
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Affiliation(s)
- Marco J Kühn
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
| | | | - Lorenzo Talà
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
| | - Yuki Inclan
- Department of MedicineUniversity of CaliforniaSan FranciscoCAUSA
| | - Ramiro Patino
- Department of MedicineUniversity of CaliforniaSan FranciscoCAUSA
| | - Xavier Pierrat
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
| | - Zainebe Al‐Mayyah
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
| | - Joanne N Engel
- Department of MedicineUniversity of CaliforniaSan FranciscoCAUSA
- Department of Microbiology and ImmunologyUniversity of CaliforniaSan FranciscoCAUSA
| | - Alexandre Persat
- Institute of Bioengineering and Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de LausanneLausanneSwitzerland
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Yao Y, Xi N, Hai E, Zhang X, Guo J, Lin Z, Huang W. PA0575 (RmcA) interacts with other c-di-GMP metabolizing proteins in Pseudomonas aeruginosa PAO1. J GEN APPL MICROBIOL 2023; 68:232-241. [PMID: 35732459 DOI: 10.2323/jgam.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
As a central signaling molecule, c-di-GMP (bis-(3,5)-cyclic diguanosine monophosphate) is becoming the focus for research in bacteria physiology. Pseudomonas aeruginosa PAO1 genome contains highly complicated c-di-GMP metabolizing genes and a number of these proteins have been identified and investigated. Especially, a sophisticated network of these proteins is emerging. In current study, mainly through Bacteria-2-Hybrid assay, we found PA0575 (RmcA), a GGDEF-EAL dual protein, to interact with two other dual proteins of PA4601 (MorA) and PA4959 (FimX). These observations imply the intricacy of c-di-GMP metabolizing protein interactions. Our work thus provides one piece of data to increase the understandings to c-di-GMP signaling.
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Affiliation(s)
- Yanxiang Yao
- School of Basic Medicine, Department of Biochemistry and Molecular Biology, Ningxia Medical University
| | - Naren Xi
- School of Basic Medicine, Department of Biochemistry and Molecular Biology, Ningxia Medical University
| | - E Hai
- School of Basic Medicine, Department of Biochemistry and Molecular Biology, Ningxia Medical University
| | - Xiaomin Zhang
- Research Center of Medical Science and Technology, Ningxia Medical University
| | - Jiayi Guo
- Research Center of Medical Science and Technology, Ningxia Medical University
| | - Zhi Lin
- School of Life Sciences, Tianjin University
| | - Weidong Huang
- School of Basic Medicine, Department of Biochemistry and Molecular Biology, Ningxia Medical University
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10
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Liu Q, Yin L, Zhang X, Zhu G, Liu H, Bai F, Cheng Z, Wu W, Jin Y. Reversion of Ceftazidime Resistance in Pseudomonas aeruginosa under Clinical Setting. Microorganisms 2022; 10:microorganisms10122395. [PMID: 36557649 PMCID: PMC9782964 DOI: 10.3390/microorganisms10122395] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/22/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa is an important nosocomial pathogen which frequently becomes resistant to most antibiotics used in chemotherapy, resulting in treatment failure among infected individuals. Although the evolutionary trajectory and molecular mechanisms for becoming β-lactam resistant have been well established for P. aeruginosa, the molecular basis of reversion from β-lactam resistant to susceptible is largely unexplored. In this study, we investigated the molecular mechanisms by which a ceftazidime-resistant clinical strain is converted to a ceftazidime-susceptible isolate under the clinical setting. RNA sequencing and genomic DNA reference mapping were conducted to compare the transcriptional profiles and chromosomal mutations between these two isolates. Our results demonstrate that a gain-of-function mutation in ampD, via deletion of a 53 bp duplicated nucleotide sequence, is the contributory factor for the conversion. Furthermore, we show for the first time that AmpD is involved in intraspecies competitiveness in P. aeruginosa. We also found that AmpD is not responsible for phenotypic changes between R1 and S2, including growth rate, motilities, pyocyanin, rhamnolipid, and biofilm production. This finding provides novel insights into the alteration of β-lactam sensitivity in P. aeruginosa under the clinical setting.
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Affiliation(s)
- Qi Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Liwen Yin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xinxin Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Guangbo Zhu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin 300100, China
| | - Huimin Liu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin 300100, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
- Correspondence:
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11
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Zhang A, Song R, Wang R, Li H, Hu D, Song B. Synthesis and Antibacterial Activities of 2- Oxo- N-phenylacetamide Derivatives Containing a Dissulfone Moiety Target on Clp. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:9356-9366. [PMID: 35862796 DOI: 10.1021/acs.jafc.2c02605] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Rice bacterial blight and rice bacterial streak are two serious rice diseases and have caused great harm to the production of rice all over the world. To develop an efficient antibacterial agent with a novel target, a series of novel 2-oxo-N-phenylacetamide derivatives containing a dissulfone moiety were synthesized, and their antibacterial activities were evaluated. Among them, compound D14 exhibited the best antibacterial activities, especially against Xoo and Xoc with EC50 values of 0.63 and 0.79 mg/L, respectively, which were much better than the commercial control of bismerthiazol (BT) (76.59 and 83.35 mg/L, respectively) and thiodiazole copper (TC) (91.72 and 114.00 mg/L, respectively). Meanwhile, compound D14 can interact with a CRP-like protein (Clp) of Pxo99A and show strong binding activity with Xoo-Clp with a Kd value of 0.52 μM, which was far superior to the corresponding Kd values of BT (183.94 μM) and TC (222.58 μM). Treatment of D14 and deletion of the clp gene could significantly reduce the expression of the clp gene and attenuate the virulence of pathogenic bacteria. These results indicated that compound D14 could be used as a potential novel agricultural bactericide and Clp can be used as a target protein for the control of plant bacterial diseases. This work provided reliable support for developing novel antibacterial agents based on Clp as a target protein.
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Affiliation(s)
- Awei Zhang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Runjiang Song
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Ronghua Wang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Hongde Li
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Deyu Hu
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Baoan Song
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
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12
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Lin S, Chen S, Li L, Cao H, Li T, Hu M, Liao L, Zhang LH, Xu Z. Genome characterization of a uropathogenic Pseudomonas aeruginosa isolate PA_HN002 with cyclic di-GMP-dependent hyper-biofilm production. Front Cell Infect Microbiol 2022; 12:956445. [PMID: 36004331 PMCID: PMC9394441 DOI: 10.3389/fcimb.2022.956445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa can cause various types of infections and is one of the most ubiquitous antibiotic-resistant pathogens found in healthcare settings. It is capable of adapting to adverse conditions by transforming its motile lifestyle to a sessile biofilm lifestyle, which induces a steady state of chronic infection. However, mechanisms triggering the lifestyle transition of P. aeruginosa strains with clinical significance are not very clear. In this study, we reported a recently isolated uropathogenic hyper-biofilm producer PA_HN002 and characterized its genome to explore genetic factors that may promote its transition into the biofilm lifestyle. We first showed that high intracellular c-di-GMP content in PA_HN002 gave rise to its attenuated motilities and extraordinary strong biofilm. Reducing the intracellular c-di-GMP content by overexpressing phosphodiesterases (PDEs) such as BifA or W909_14950 converted the biofilm and motility phenotypes. Whole genome sequencing and comprehensive analysis of all the c-di-GMP metabolizing enzymes led to the identification of multiple mutations within PDEs. Gene expression assays further indicated that the shifted expression profile of c-di-GMP metabolizing enzymes in PA_HN002 might mainly contribute to its elevated production of intracellular c-di-GMP and enhanced biofilm formation. Moreover, mobile genetic elements which might interfere the endogenous regulatory network of c-di-GMP metabolism in PA_HN002 were analyzed. This study showed a reprogrammed expression profile of c-di-GMP metabolizing enzymes which may promote the pathoadaption of clinical P. aeruginosa into biofilm producers.
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Affiliation(s)
- Siying Lin
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Shuzhen Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Li Li
- Women and Children’s Health Institute, Guangdong Women and Children Hospital, Guangzhou, China
- *Correspondence: Li Li, ; Zeling Xu,
| | - Huiluo Cao
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Ting Li
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Ming Hu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Lisheng Liao
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Lian-Hui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
| | - Zeling Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China
- *Correspondence: Li Li, ; Zeling Xu,
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13
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Eilers K, Kuok Hoong Yam J, Morton R, Mei Hui Yong A, Brizuela J, Hadjicharalambous C, Liu X, Givskov M, Rice SA, Filloux A. Phenotypic and integrated analysis of a comprehensive Pseudomonas aeruginosa PAO1 library of mutants lacking cyclic-di-GMP-related genes. Front Microbiol 2022; 13:949597. [PMID: 35935233 PMCID: PMC9355167 DOI: 10.3389/fmicb.2022.949597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative bacterium that is able to survive and adapt in a multitude of niches as well as thrive within many different hosts. This versatility lies within its large genome of ca. 6 Mbp and a tight control in the expression of thousands of genes. Among the regulatory mechanisms widespread in bacteria, cyclic-di-GMP signaling is one which influences all levels of control. c-di-GMP is made by diguanylate cyclases and degraded by phosphodiesterases, while the intracellular level of this molecule drives phenotypic responses. Signaling involves the modification of enzymes' or proteins' function upon c-di-GMP binding, including modifying the activity of regulators which in turn will impact the transcriptome. In P. aeruginosa, there are ca. 40 genes encoding putative DGCs or PDEs. The combined activity of those enzymes should reflect the overall c-di-GMP concentration, while specific phenotypic outputs could be correlated to a given set of dgc/pde. This notion of specificity has been addressed in several studies and different strains of P. aeruginosa. Here, we engineered a mutant library for the 41 individual dgc/pde genes in P. aeruginosa PAO1. In most cases, we observed a significant to slight variation in the global c-di-GMP pool of cells grown planktonically, while several mutants display a phenotypic impact on biofilm including initial attachment and maturation. If this observation of minor changes in c-di-GMP level correlating with significant phenotypic impact appears to be true, it further supports the idea of a local vs global c-di-GMP pool. In contrast, there was little to no effect on motility, which differs from previous studies. Our RNA-seq analysis indicated that all PAO1 dgc/pde genes were expressed in both planktonic and biofilm growth conditions and our work suggests that c-di-GMP networks need to be reconstructed for each strain separately and cannot be extrapolated from one to another.
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Affiliation(s)
- Kira Eilers
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Joey Kuok Hoong Yam
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Richard Morton
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Adeline Mei Hui Yong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jaime Brizuela
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
- Department of Medical Microbiology, Amsterdam UMC, Universitair Medische Centra, University of Amsterdam, Amsterdam, Netherlands
| | - Corina Hadjicharalambous
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zurich, Switzerland
| | - Xianghui Liu
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Michael Givskov
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Scott A. Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Westmead and Microbiomes for One Systems Health, Melbourne, VIC, Australia
| | - Alain Filloux
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
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14
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Alviz-Gazitua P, González A, Lee MR, Aranda CP. Molecular Relationships in Biofilm Formation and the Biosynthesis of Exoproducts in Pseudoalteromonas spp. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:431-447. [PMID: 35486299 DOI: 10.1007/s10126-022-10097-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
Most members of the Pseudoalteromonas genus have been isolated from living surfaces as members of epiphytic and epizooic microbiomes on marine macroorganisms. Commonly Pseudoalteromonas isolates are reported as a source of bioactive exoproducts, i.e., secondary metabolites, such as exopolymeric substances and extracellular enzymes. The experimental conditions for the production of these agents are commonly associated with sessile metabolic states such as biofilms or liquid cultures in the stationary growth phase. Despite this, the molecular mechanisms that connect biofilm formation and the biosynthesis of exoproducts in Pseudoalteromonas isolates have rarely been mentioned in the literature. This review compiles empirical evidence about exoproduct biosynthesis conditions and molecular mechanisms that regulate sessile metabolic states in Pseudoalteromonas species, to provide a comprehensive perspective on the regulatory convergences that generate the recurrent coexistence of both phenomena in this bacterial genus. This synthesis aims to provide perspectives on the extent of this phenomenon for the optimization of bioprospection studies and biotechnology processes based on these bacteria.
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Affiliation(s)
- P Alviz-Gazitua
- Departamento de Ciencias Biológicas y Biodiversidad, Universidad de Los Lagos, Avda. Fuchslocher 1305, P. Box 5290000, Osorno, Chile
| | - A González
- Departamento de Ciencias Biológicas y Biodiversidad, Universidad de Los Lagos, Avda. Fuchslocher 1305, P. Box 5290000, Osorno, Chile
| | - M R Lee
- Centro i~mar, Universidad de Los Lagos, Camino a Chinquihue km 6, P. Box 5480000, Puerto Montt, Chile
| | - C P Aranda
- Departamento de Ciencias Biológicas y Biodiversidad, Universidad de Los Lagos, Avda. Fuchslocher 1305, P. Box 5290000, Osorno, Chile.
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15
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A noncanonical cytochrome c stimulates calcium binding by PilY1 for type IVa pili formation. Proc Natl Acad Sci U S A 2022; 119:2115061119. [PMID: 35121662 PMCID: PMC8833165 DOI: 10.1073/pnas.2115061119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2021] [Indexed: 12/23/2022] Open
Abstract
Type IVa pili (T4aP) are versatile bacterial cell surface structures that undergo extension/adhesion/retraction cycles powered by the cell envelope-spanning T4aP machine. In this machine, a complex composed of four minor pilins and PilY1 primes T4aP extension and is also present at the pilus tip mediating adhesion. Similar to many several other bacteria, Myxococcus xanthus contains multiple minor pilins/PilY1 sets that are incompletely understood. Here, we report that minor pilins and PilY1 (PilY1.1) of cluster_1 form priming and tip complexes contingent on calcium and a noncanonical cytochrome c (TfcP) with an unusual His/Cys heme ligation. We provide evidence that TfcP is unlikely to participate in electron transport and instead stimulates calcium binding by PilY1.1 at low-calcium concentrations, thereby stabilizing PilY1.1 and enabling T4aP function in a broader range of calcium concentrations. These results not only identify a previously undescribed function of cytochromes c but also illustrate how incorporation of an accessory factor expands the environmental range under which the T4aP system functions.
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16
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Expression of a phage-encoded Gp21 protein protects Pseudomonas aeruginosa against phage infection. J Virol 2022; 96:e0176921. [PMID: 35020473 DOI: 10.1128/jvi.01769-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There is a continuously expanding gap between predicted phage gene sequences and their corresponding functions, which largely hampered the development of phage therapy. Previous studies reported several phage proteins that could interfere with the intracellular processes of the host to obtain efficient infection. But few phage proteins that protect host against phage infection has been identified and characterized in detail. Here, we isolate a phage vB_Pae_QDWS capable of infecting Pseudomonas aeruginosa PAO1, and report its encoded Gp21 protein protects PAO1 against phage infection. Expressing of Gp21 regulate bacterial quorum sensing with an inhibitory effect in low cell density and activation effect in high cell density. By testing the TFPs-mediated twitching motility and transmission electron microscopy analysis, Gp21 was found decreased the pilus synthesis. Further constructing the TFPs synthesis gene pilB mutant and performing adsorption and phage resistance assay, we demonstrated Gp21 protein could block phage infection via decreasing the TFPs-mediated phage adsorption. Gp21 is a novel protein that inhibit phage efficacy against bacteria. The study deepens our understanding of phage-host interactions. Importance The majority of the annotated phage genes are currently deposited as "hypothetical protein" with unknown function. Researches revealed that some phage proteins serve to inhibit or redirect the host intracellular processes for phage infection. Differently, we report a phage encoded protein Gp21 that protect the host against phage infection. The pathways that Gp21 involved in anti-phage defense in Pseudomonas aeruginosa PAO1 are interfering with quorum sensing and decreasing the type IV pilus-mediated phage adsorption. Gp21 is a novel protein with a low sequence homology with other reported twitching inhibitory proteins. As a lytic phage derived protein, Gp21 expression protects P. aeruginosa PAO1 from reinfection by phage vB_Pae_QDWS, which may explain the well-known pseudolysogeny caused by virulent phages. Our discoveries provide valuable new insight into the phage-host evolutionary dynamics.
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17
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Wei C, Wang S, Liu P, Cheng ST, Qian G, Wang S, Fu Y, Qian W, Sun W. The PdeK-PdeR two-component system promotes unipolar localization of FimX and pilus extension in Xanthomonas oryzae pv. oryzicola. Sci Signal 2021; 14:eabi9589. [PMID: 34520229 DOI: 10.1126/scisignal.abi9589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Chao Wei
- Department of Plant Pathology and MOA Key Laboratory of Pest Monitoring and Green Management, and Joint International Research Laboratory of Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing 100193, China
| | - Shanzhi Wang
- Department of Plant Pathology and MOA Key Laboratory of Pest Monitoring and Green Management, and Joint International Research Laboratory of Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing 100193, China
| | - Pengwei Liu
- College of Plant Protection, Jilin Agricultural University, Changchun 130118, Jilin, China
| | - Shou-Ting Cheng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guoliang Qian
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Shuwei Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenxian Sun
- Department of Plant Pathology and MOA Key Laboratory of Pest Monitoring and Green Management, and Joint International Research Laboratory of Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing 100193, China.,College of Plant Protection, Jilin Agricultural University, Changchun 130118, Jilin, China
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18
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Llontop EE, Cenens W, Favaro DC, Sgro GG, Salinas RK, Guzzo CR, Farah CS. The PilB-PilZ-FimX regulatory complex of the Type IV pilus from Xanthomonas citri. PLoS Pathog 2021; 17:e1009808. [PMID: 34398935 PMCID: PMC8389850 DOI: 10.1371/journal.ppat.1009808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 08/26/2021] [Accepted: 07/17/2021] [Indexed: 11/19/2022] Open
Abstract
Type IV pili (T4P) are thin and flexible filaments found on the surface of a wide range of Gram-negative bacteria that undergo cycles of extension and retraction and participate in a variety of important functions related to lifestyle, defense and pathogenesis. During pilus extensions, the PilB ATPase energizes the polymerization of pilin monomers from the inner membrane. In Xanthomonas citri, two cytosolic proteins, PilZ and the c-di-GMP receptor FimX, are involved in the regulation of T4P biogenesis through interactions with PilB. In vivo fluorescence microscopy studies show that PilB, PilZ and FimX all colocalize to the leading poles of X. citri cells during twitching motility and that this colocalization is dependent on the presence of all three proteins. We demonstrate that full-length PilB, PilZ and FimX can interact to form a stable complex as can PilB N-terminal, PilZ and FimX C-terminal fragments. We present the crystal structures of two binary complexes: i) that of the PilB N-terminal domain, encompassing sub-domains ND0 and ND1, bound to PilZ and ii) PilZ bound to the FimX EAL domain within a larger fragment containing both GGDEF and EAL domains. Evaluation of PilZ interactions with PilB and the FimX EAL domain in these and previously published structures, in conjunction with mutagenesis studies and functional assays, allow us to propose an internally consistent model for the PilB-PilZ-FimX complex and its interactions with the PilM-PilN complex in the context of the inner membrane platform of the X. citri Type IV pilus.
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Affiliation(s)
- Edgar E. Llontop
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - William Cenens
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Denize C. Favaro
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Departamento de Química Orgânica, Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
| | - Germán G. Sgro
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Roberto K. Salinas
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Cristiane R. Guzzo
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Chuck S. Farah
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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19
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Banerjee P, Sahoo PK, Sheenu, Adhikary A, Ruhal R, Jain D. Molecular and structural facets of c-di-GMP signalling associated with biofilm formation in Pseudomonas aeruginosa. Mol Aspects Med 2021; 81:101001. [PMID: 34311995 DOI: 10.1016/j.mam.2021.101001] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/09/2021] [Accepted: 07/16/2021] [Indexed: 12/29/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen and is the primary cause of nosocomial infections. Biofilm formation by this organism results in chronic and hard to eradicate infections. The intracellular signalling molecule bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a secondary messenger in bacterial cells crucial for motile to sessile transition. The signalling pathway components encompass two classes of enzymes with antagonistic activities, the diguanylate cyclases (DGCs) and phosphodiesterases (PDEs) that regulate the cellular levels of c-di-GMP at distinct stages of biofilm initiation, maturation and dispersion. This review summarizes the structural analysis and functional studies of the DGCs and PDEs involved in biofilm regulation in P. aeruginosa. In addition, we also describe the effector proteins that sense the perturbations in c-di-GMP levels to elicit a functional output. Finally, we discuss possible mechanisms that allow the dynamic levels of c-di-GMP to regulate cognate cellular response. Uncovering the details of the regulation of the c-di-GMP signalling pathway is vital for understanding the behaviour of the pathogen and characterization of novel targets for anti-biofilm interventions.
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Affiliation(s)
- Priyajit Banerjee
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India; Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha, 751024, India
| | - Pankaj Kumar Sahoo
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India
| | - Sheenu
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India
| | - Anirban Adhikary
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India
| | - Rohit Ruhal
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India
| | - Deepti Jain
- Transcription Regulation Lab, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India.
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20
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Abstract
Single cells across kingdoms of life explore, prey, escape, or congregate using surface-specific motility. Motile eukaryotic cells use chemotaxis to direct migration on surfaces. However, how bacteria control surface motility remains underexplored. Pseudomonas aeruginosa twitches on surfaces by successive extension and retraction of extracellular filaments called type IV pili. Here, we show that P. aeruginosa directs twitching by sensing mechanical input generated by type IV pili. The Chp sensory system performs spatially resolved mechanosensing by harnessing two response regulators with antagonistic functions. Our results demonstrate that sensory systems, whose input often remains elusive, can sense mechanical signals to actively steer motility. Furthermore, Chp establishes a signaling principle shared with higher-order organisms, identifying a conserved strategy to transduce spatially resolved signals. The opportunistic pathogen Pseudomonas aeruginosa explores surfaces using twitching motility powered by retractile extracellular filaments called type IV pili (T4P). Single cells twitch by sequential T4P extension, attachment, and retraction. How single cells coordinate T4P to efficiently navigate surfaces remains unclear. We demonstrate that P. aeruginosa actively directs twitching in the direction of mechanical input from T4P in a process called mechanotaxis. The Chp chemotaxis-like system controls the balance of forward and reverse twitching migration of single cells in response to the mechanical signal. Collisions between twitching cells stimulate reversals, but Chp mutants either always or never reverse. As a result, while wild-type cells colonize surfaces uniformly, collision-blind Chp mutants jam, demonstrating a function for mechanosensing in regulating group behavior. On surfaces, Chp senses T4P attachment at one pole, thereby sensing a spatially resolved signal. As a result, the Chp response regulators PilG and PilH control the polarization of the extension motor PilB. PilG stimulates polarization favoring forward migration, while PilH inhibits polarization, inducing reversal. Subcellular segregation of PilG and PilH efficiently orchestrates their antagonistic functions, ultimately enabling rapid reversals upon perturbations. The distinct localization of response regulators establishes a signaling landscape known as local excitation–global inhibition in higher-order organisms, identifying a conserved strategy to transduce spatially resolved signals.
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21
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Abstract
Bacteria thrive both in liquids and attached to surfaces. The concentration of bacteria on surfaces is generally much higher than in the surrounding environment, offering bacteria ample opportunity for mutualistic, symbiotic, and pathogenic interactions. To efficiently populate surfaces, they have evolved mechanisms to sense mechanical or chemical cues upon contact with solid substrata. This is of particular importance for pathogens that interact with host tissue surfaces. In this review we discuss how bacteria are able to sense surfaces and how they use this information to adapt their physiology and behavior to this new environment. We first survey mechanosensing and chemosensing mechanisms and outline how specific macromolecular structures can inform bacteria about surfaces. We then discuss how mechanical cues are converted to biochemical signals to activate specific cellular processes in a defined chronological order and describe the role of two key second messengers, c-di-GMP and cAMP, in this process.
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Affiliation(s)
| | - Urs Jenal
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland; ,
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22
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Xu K, Lin L, Shen D, Chou SH, Qian G. Clp is a "busy" transcription factor in the bacterial warrior, Lysobacter enzymogenes. Comput Struct Biotechnol J 2021; 19:3564-3572. [PMID: 34257836 PMCID: PMC8246147 DOI: 10.1016/j.csbj.2021.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/13/2021] [Accepted: 06/13/2021] [Indexed: 02/06/2023] Open
Abstract
Cyclic AMP receptor protein (CRP) is a well-characterized group of global transcription factors in bacteria. They are known to regulate numerous cellular processes by binding DNA and/or cAMP (a ligand called bacterial second messenger) to control target gene expression. Gram-negative Lysobacter enzymogenes is a soilborne, plant-beneficial bacterium without flagella that can fight against filamentous fungi and oomycete. Driven by the type IV pilus (T4P) system, this bacterium moves to nearby pathogens and uses a “mobile-attack” antifungal strategy to kill them via heat-stable antifungal factor (HSAF) and abundant lyases. This strategy is controlled by a unique “busy” transcription factor Clp, which is a CRP-like protein that is inactivated by binding of c-di-GMP, another ubiquitous second messenger of bacteria. In this review, we summarize the current progress in how Clp initiates a “mobile-attack” strategy through a series of previously uncharacterized mechanisms, including binding to DNA in a unique pattern, directly interacting with or responding to various small molecules, and interacting specifically with proteins adopting distinct structure. Together, these characteristics highlight the multifunctional roles of Clp in L. enzymogenes, a powerful bacterial warrior against fungal pathogens.
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Affiliation(s)
- Kangwen Xu
- College of Plant Protection, Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, PR China
| | - Long Lin
- College of Plant Protection, Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, PR China
| | - Danyu Shen
- College of Plant Protection, Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, PR China
| | - Shan-Ho Chou
- Institute of Biochemistry, and NCHU Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Guoliang Qian
- College of Plant Protection, Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu 210095, PR China
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23
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Xu K, Shen D, Yang N, Chou S, Gomelsky M, Qian G. Coordinated control of the type IV pili and c-di-GMP-dependent antifungal antibiotic production in Lysobacter by the response regulator PilR. MOLECULAR PLANT PATHOLOGY 2021; 22:602-617. [PMID: 33709522 PMCID: PMC8035640 DOI: 10.1111/mpp.13046] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/24/2021] [Accepted: 02/04/2021] [Indexed: 05/05/2023]
Abstract
In the soil gammaproteobacterium Lysobacter enzymogenes, a natural fungal predator, the response regulator PilR controls type IV pili (T4P)-mediated twitching motility as well as synthesis of the heat-stable antifungal factor (HSAF). Earlier we showed that PilR acts via the second messenger, c-di-GMP; however, the mechanism remained unknown. Here, we describe how PilR, c-di-GMP signalling, and HSAF synthesis are connected. We screened genes for putative diguanylate cyclases (c-di-GMP synthases) and found that PilR binds to the promoter region of lchD and down-regulates its transcription. The DNA-binding affinity of PilR, and therefore its repressor function, are enhanced by phosphorylation by its cognate histidine kinase, PilS. The lchD gene product is a diguanylate cyclase, and the decrease in LchD levels shifts the ratio of c-di-GMP-bound and c-di-GMP-free transcription factor Clp, a key activator of the HSAF biosynthesis operon expression. Furthermore, Clp directly interacts with LchD and enhances its diguanylate cyclase activity. Therefore, the PilS-PilR two-component system activates T4P-motility while simultaneously decreasing c-di-GMP levels and promoting HSAF production via the highly specific LchD-c-di-GMP-Clp pathway. Coordinated increase in motility and secretion of the "long-distance" antifungal weapon HSAF is expected to ensure safer grazing of L. enzymogenes on soil or plant surfaces, unimpeded by fungal competitors, or to facilitate bacterial preying on killed fungal cells. This study uncovered the mechanism of coregulated pili-based motility and production of an antifungal antibiotic in L. enzymogenes, showcased the expanded range of functions of the PilS-PilR system, and highlighted exquisite specificity in c-di-GMP-mediated circuits.
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Affiliation(s)
- Kangwen Xu
- College of Plant Protection (Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjingP.R. China
| | - Danyu Shen
- College of Plant Protection (Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjingP.R. China
| | - Nianda Yang
- College of Plant Protection (Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjingP.R. China
| | - Shan‐Ho Chou
- Institute of Biochemistry and NCHU Agricultural Biotechnology CenterNational Chung Hsing UniversityTaichungTaiwan, ROC
| | - Mark Gomelsky
- Department of Molecular BiologyUniversity of WyomingLaramieWyomingUSA
| | - Guoliang Qian
- College of Plant Protection (Laboratory of Plant Immunity, Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjingP.R. China
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24
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Koch MD, Fei C, Wingreen NS, Shaevitz JW, Gitai Z. Competitive binding of independent extension and retraction motors explains the quantitative dynamics of type IV pili. Proc Natl Acad Sci U S A 2021; 118:e2014926118. [PMID: 33593905 PMCID: PMC7923367 DOI: 10.1073/pnas.2014926118] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Type IV pili (TFP) function through cycles of extension and retraction. The coordination of these cycles remains mysterious due to a lack of quantitative measurements of multiple features of TFP dynamics. Here, we fluorescently label TFP in the pathogen Pseudomonas aeruginosa and track full extension and retraction cycles of individual filaments. Polymerization and depolymerization dynamics are stochastic; TFP are made at random times and extend, pause, and retract for random lengths of time. TFP can also pause for extended periods between two extension or two retraction events in both wild-type cells and a slowly retracting PilT mutant. We developed a biophysical model based on the stochastic binding of two dedicated extension and retraction motors to the same pilus machine that predicts the observed features of the data with no free parameters. We show that only a model in which both motors stochastically bind and unbind to the pilus machine independent of the piliation state of the machine quantitatively explains the experimentally observed pilus production rate. In experimental support of this model, we show that the abundance of the retraction motor dictates the pilus production rate and that PilT is bound to pilus machines even in their unpiliated state. Together, the strong quantitative agreement of our model with a variety of experiments suggests that the entire repetitive cycle of pilus extension and retraction is coordinated by the competition of stochastic motor binding to the pilus machine, and that the retraction motor is the major throttle for pilus production.
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Affiliation(s)
- Matthias D Koch
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
| | - Chenyi Fei
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
| | - Ned S Wingreen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
| | - Joshua W Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540;
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08540
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540;
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25
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Dynamic swimming pattern of Pseudomonas aeruginosa near a vertical wall during initial attachment stages of biofilm formation. Sci Rep 2021; 11:1952. [PMID: 33479476 PMCID: PMC7820011 DOI: 10.1038/s41598-021-81621-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/08/2021] [Indexed: 11/22/2022] Open
Abstract
Studying the swimming behaviour of bacteria in 3 dimensions (3D) allows us to understand critical biological processes, such as biofilm formation. It is still unclear how near wall swimming behaviour may regulate the initial attachment and biofilm formation. It is challenging to address this as visualizing the movement of bacteria with reasonable spatial and temporal resolution in a high-throughput manner is technically difficult. Here, we compared the near wall (vertical) swimming behaviour of P. aeruginosa (PAO1) and its mutants ΔdipA (reduced in swarming motility and increased in biofilm formation) and ΔfimX (deficient in twitching motility and reduced in biofilm formation) using our new imaging technique based on light sheet microscopy. We found that P. aeruginosa (PAO1) increases its speed and changes its swimming angle drastically when it gets closer to a wall. In contrast, ΔdipA mutant moves toward the wall with steady speed without changing of swimming angle. The near wall behavior of ΔdipA allows it to be more effective to interact with the wall or wall-attached cells, thus leading to more adhesion events and a larger biofilm volume during initial attachment when compared with PAO1. Furthermore, we found that ΔfimX has a similar near wall swimming behavior as PAO1. However, it has a higher dispersal frequency and smaller biofilm formation when compared with PAO1 which can be explained by its poor twitching motility. Together, we propose that near wall swimming behavior of P. aeruginosa plays an important role in the regulation of initial attachment and biofilm formation.
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26
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Kimkes TEP, Heinemann M. How bacteria recognise and respond to surface contact. FEMS Microbiol Rev 2020; 44:106-122. [PMID: 31769807 PMCID: PMC7053574 DOI: 10.1093/femsre/fuz029] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 11/23/2019] [Indexed: 12/27/2022] Open
Abstract
Bacterial biofilms can cause medical problems and issues in technical systems. While a large body of knowledge exists on the phenotypes of planktonic and of sessile cells in mature biofilms, our understanding of what happens when bacteria change from the planktonic to the sessile state is still very incomplete. Fundamental questions are unanswered: for instance, how do bacteria sense that they are in contact with a surface, and what are the very initial cellular responses to surface contact. Here, we review the current knowledge on the signals that bacteria could perceive once they attach to a surface, the signal transduction systems that could be involved in sensing the surface contact and the cellular responses that are triggered as a consequence to surface contact ultimately leading to biofilm formation. Finally, as the main obstacle in investigating the initial responses to surface contact has been the difficulty to experimentally study the dynamic response of single cells upon surface attachment, we also review recent experimental approaches that could be employed to study bacterial surface sensing, which ultimately could lead to an improved understanding of how biofilm formation could be prevented.
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Affiliation(s)
- Tom E P Kimkes
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Matthias Heinemann
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
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27
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The small GTPase MglA together with the TPR domain protein SgmX stimulates type IV pili formation in M. xanthus. Proc Natl Acad Sci U S A 2020; 117:23859-23868. [PMID: 32900945 PMCID: PMC7519303 DOI: 10.1073/pnas.2004722117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many bacteria move across surfaces using type IV pili (T4P). The piliation pattern varies between species; however, the underlying mechanisms governing these patterns remain largely unknown. Here, we demonstrate that in the rod-shaped Myxococcus xanthus cells, the unipolar formation of T4P at the leading cell pole is the result of stimulation by the small GTPase MglA together with the effector protein SgmX, while MglB, the cognate MglA GTPase activating protein (GAP) that localizes to the lagging cell pole, blocks this stimulation at the lagging pole due to its GAP activity. During reversals, MglA/SgmX and MglB switch polarity, laying the foundation for T4P formation at the new leading cell pole and inhibition of T4P formation at the former leading cell pole. Bacteria can move across surfaces using type IV pili (T4P), which undergo cycles of extension, adhesion, and retraction. The T4P localization pattern varies between species; however, the underlying mechanisms are largely unknown. In the rod-shaped Myxococcus xanthus cells, T4P localize at the leading cell pole. As cells reverse their direction of movement, T4P are disassembled at the old leading pole and then form at the new leading pole. Thus, cells can form T4P at both poles but engage only one pole at a time in T4P formation. Here, we address how this T4P unipolarity is realized. We demonstrate that the small Ras-like GTPase MglA stimulates T4P formation in its GTP-bound state by direct interaction with the tetratricopeptide repeat (TPR) domain-containing protein SgmX. SgmX, in turn, is important for polar localization of the T4P extension ATPase PilB. The cognate MglA GTPase activating protein (GAP) MglB, which localizes mainly to the lagging cell pole, indirectly blocks T4P formation at this pole by stimulating the conversion of MglA-GTP to MglA-GDP. Based on these findings, we propose a model whereby T4P unipolarity is accomplished by stimulation of T4P formation at the leading pole by MglA-GTP and SgmX and indirect inhibition of T4P formation at the lagging pole by MglB due to its MglA GAP activity. During reversals, MglA, SgmX, and MglB switch polarity, thus laying the foundation for T4P formation at the new leading pole and inhibition of T4P formation at the new lagging pole.
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28
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Cyclic-di-GMP and ADP bind to separate domains of PilB as mutual allosteric effectors. Biochem J 2020; 477:213-226. [PMID: 31868878 PMCID: PMC6957770 DOI: 10.1042/bcj20190809] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/18/2019] [Accepted: 12/23/2019] [Indexed: 01/12/2023]
Abstract
PilB is the assembly ATPase for the bacterial type IV pilus (T4P), and as a consequence, it is essential for T4P-mediated bacterial motility. In some cases, PilB has been demonstrated to regulate the production of exopolysaccharide (EPS) during bacterial biofilm development independently of or in addition to its function in pilus assembly. While the ATPase activity of PilB resides at its C-terminal region, the N terminus of a subset of PilBs forms a novel cyclic-di-GMP (cdG)-binding domain. This multi-domain structure suggests that PilB binds cdG and adenine nucleotides through separate domains which may influence the functionality of PilB in both motility and biofilm development. Here, Chloracidobacterium thermophilum PilB is used to investigate ligand binding by its separate domains and by the full-length protein. Our results confirm the specificity of these individual domains for their respective ligands and demonstrate communications between these domains in the full-length protein. It is clear that when the N- and the C-terminal domains of PilB bind to cdG and ADP, respectively, they mutually influence each other in conformation and in their binding to ligands. We propose that the interactions between these domains in response to their ligands play critical roles in modulating or controlling the functions of PilB as a regulator of EPS production and as the T4P assembly ATPase.
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29
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Feng Q, Ahator SD, Zhou T, Liu Z, Lin Q, Liu Y, Huang J, Zhou J, Zhang LH. Regulation of Exopolysaccharide Production by ProE, a Cyclic-Di-GMP Phosphodiesterase in Pseudomonas aeruginosa PAO1. Front Microbiol 2020; 11:1226. [PMID: 32582123 PMCID: PMC7290235 DOI: 10.3389/fmicb.2020.01226] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/14/2020] [Indexed: 11/13/2022] Open
Abstract
The ubiquitous second messenger c-di-GMP is involved in regulation of multiple biological functions including the important extracellular matrix exopolysaccharides (EPS). But how c-di-GMP metabolic proteins influence EPS and their enzymatic properties are not fully understood. Here we showed that deletion of proE, which encodes a protein with GGDEF-EAL hybrid domains, significantly increased the transcriptional expression of the genes encoding EPS production in Pseudomonas aeruginosa PAO1 and changed the bacterial colony morphology. Our data showed that ProE is a very active phosphodiesterase (PDE), with a high enzyme activity in degradation of c-di-GMP. Interestingly, the optimal activity of ProE was found in the presence of Co2+, unlike other PDEs that commonly rely on Mg2+ or Mn2+ for best performance. Furthermore, we identified three widely conserved novel residues that are critical for the function of ProE through site-directed mutagenesis. Subsequent study showed that ProE, together with other three key PDEs, i.e., RbdA, BifA, and DipA regulate the EPS production in P. aeruginosa PAO1. Moreover, by using the GFP-fusion approach, we observed that these four EPS associated-PDEs showed a polar localization pattern in general. Taken together, our data unveil the molecular mechanisms of ProE in regulation of EPS production, and provide a new insight on its enzymatic properties in degradation of c-di-GMP.
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Affiliation(s)
- Qishun Feng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Stephen Dela Ahator
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Tian Zhou
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Zhiqing Liu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Qiqi Lin
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Yang Liu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Jiahui Huang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Jianuan Zhou
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Lian-Hui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
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30
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Valentini M, Filloux A. Multiple Roles of c-di-GMP Signaling in Bacterial Pathogenesis. Annu Rev Microbiol 2020; 73:387-406. [PMID: 31500536 DOI: 10.1146/annurev-micro-020518-115555] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The intracellular signaling molecule cyclic di-GMP (c-di-GMP) regulates the lifestyle of bacteria and controls many key functions and mechanisms. In the case of bacterial pathogens, a wide variety of virulence lifestyle factors have been shown to be regulated by c-di-GMP. Evidence of the importance of this molecule for bacterial pathogenesis has become so great that new antimicrobial agents are tested for their capacity of targeting c-di-GMP signaling. This review summarizes the current knowledge on this topic and reveals its application for the development of new antivirulence intervention strategies.
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Affiliation(s)
- Martina Valentini
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva 4, Switzerland;
| | - Alain Filloux
- MRC Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, SW7 2AZ London, United Kingdom;
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31
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Ma GL, Chandra H, Liang ZX. Taming the flagellar motor of pseudomonads with a nucleotide messenger. Environ Microbiol 2020; 22:2496-2513. [PMID: 32329141 DOI: 10.1111/1462-2920.15036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 01/11/2023]
Abstract
Pseudomonads rely on the flagellar motor to rotate a polar flagellum for swimming and swarming, and to sense surfaces for initiating the motile-to-sessile transition to adopt a surface-dwelling lifestyle. Deciphering the function and regulation of the flagellar motor is of paramount importance for understanding the behaviours of environmental and pathogenic pseudomonads. Recent studies disclosed the preeminent role played by the messenger c-di-GMP in controlling the real-time performance of the flagellar motor in pseudomonads. The studies revealed that c-di-GMP controls the dynamic exchange of flagellar stator units to regulate motor torque/speed and modulates the frequency of flagellar motor switching via the chemosensory signalling pathways. Apart from being a rotary motor, the flagellar motor is emerging as a mechanosensor that transduces surface-induced mechanical signals into an increase of cellular c-di-GMP concentration to initiate the cellular programs required for long-term colonization. Collectively, the studies generate long-awaited mechanistic insights into how c-di-GMP regulates bacterial motility and the motile-to-sessile transition. The new findings also raise the fundamental questions of how cellular c-di-GMP concentrations are dynamically coupled to flagellar output and the proton-motive force, and how c-di-GMP signalling is coordinated spatiotemporally to fine-tune flagellar response and the behaviour of pseudomonads in solutions and on surfaces.
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Affiliation(s)
- Guang-Lei Ma
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
| | - Hartono Chandra
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore.,Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
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32
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Cai YM, Hutchin A, Craddock J, Walsh MA, Webb JS, Tews I. Differential impact on motility and biofilm dispersal of closely related phosphodiesterases in Pseudomonas aeruginosa. Sci Rep 2020; 10:6232. [PMID: 32277108 PMCID: PMC7148300 DOI: 10.1038/s41598-020-63008-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 02/28/2020] [Indexed: 12/31/2022] Open
Abstract
In Pseudomonas aeruginosa, the transition between planktonic and biofilm lifestyles is modulated by the intracellular secondary messenger cyclic dimeric-GMP (c-di-GMP) in response to environmental conditions. Here, we used gene deletions to investigate how the environmental stimulus nitric oxide (NO) is linked to biofilm dispersal, focusing on biofilm dispersal phenotype from proteins containing putative c-di-GMP turnover and Per-Arnt-Sim (PAS) sensory domains. We document opposed physiological roles for the genes ΔrbdA and Δpa2072 that encode proteins with identical domain structure: while ΔrbdA showed elevated c-di-GMP levels, restricted motility and promoted biofilm formation, c-di-GMP levels were decreased in Δpa2072, and biofilm formation was inhibited, compared to wild type. A second pair of genes, ΔfimX and ΔdipA, were selected on the basis of predicted impaired c-di-GMP turnover function: ΔfimX showed increased, ΔdipA decreased NO induced biofilm dispersal, and the genes effected different types of motility, with reduced twitching for ΔfimX and reduced swimming for ΔdipA. For all four deletion mutants we find that NO-induced biomass reduction correlates with increased NO-driven swarming, underlining a significant role for this motility in biofilm dispersal. Hence P. aeruginosa is able to differentiate c-di-GMP output using structurally highly related proteins that can contain degenerate c-di-GMP turnover domains.
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Affiliation(s)
- Yu-Ming Cai
- National Biofilms Innovation Centre, University of Southampton, Southampton, SO17 1BJ, UK.,Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Andrew Hutchin
- Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK.,Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.,Structure and Function of Biological Membranes Lab, Université Libre de Bruxelles, Boulevard du Triomphe, 1050, Bruxelles, Belgium
| | - Jack Craddock
- National Biofilms Innovation Centre, University of Southampton, Southampton, SO17 1BJ, UK.,Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Martin A Walsh
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.,Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0FA, UK
| | - Jeremy S Webb
- National Biofilms Innovation Centre, University of Southampton, Southampton, SO17 1BJ, UK.,Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Ivo Tews
- National Biofilms Innovation Centre, University of Southampton, Southampton, SO17 1BJ, UK. .,Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
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33
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Floyd KA, Lee CK, Xian W, Nametalla M, Valentine A, Crair B, Zhu S, Hughes HQ, Chlebek JL, Wu DC, Hwan Park J, Farhat AM, Lomba CJ, Ellison CK, Brun YV, Campos-Gomez J, Dalia AB, Liu J, Biais N, Wong GCL, Yildiz FH. c-di-GMP modulates type IV MSHA pilus retraction and surface attachment in Vibrio cholerae. Nat Commun 2020; 11:1549. [PMID: 32214098 PMCID: PMC7096442 DOI: 10.1038/s41467-020-15331-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 03/02/2020] [Indexed: 11/21/2022] Open
Abstract
Biofilm formation by Vibrio cholerae facilitates environmental persistence, and hyperinfectivity within the host. Biofilm formation is regulated by 3',5'-cyclic diguanylate (c-di-GMP) and requires production of the type IV mannose-sensitive hemagglutinin (MSHA) pilus. Here, we show that the MSHA pilus is a dynamic extendable and retractable system, and its activity is directly controlled by c-di-GMP. The interaction between c-di-GMP and the ATPase MshE promotes pilus extension, whereas low levels of c-di-GMP correlate with enhanced retraction. Loss of retraction facilitated by the ATPase PilT increases near-surface roaming motility, and impairs initial surface attachment. However, prolonged retraction upon surface attachment results in reduced MSHA-mediated surface anchoring and increased levels of detachment. Our results indicate that c-di-GMP directly controls MshE activity, thus regulating MSHA pilus extension and retraction dynamics, and modulating V. cholerae surface attachment and colonization.
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Affiliation(s)
- Kyle A Floyd
- Department of Microbiology and Environmental Toxicology, University of California - Santa Cruz, 1156 High St., BioMed 245, Santa Cruz, CA, 95064, USA
| | - Calvin K Lee
- Departments of Bioengineering, Chemistry and Biochemistry, California Nano Systems Institute, University of California - Los Angeles, 420 Westwood Plaza, Room 5121 Engineering V, Los Angeles, CA, 90095, USA
| | - Wujing Xian
- Departments of Bioengineering, Chemistry and Biochemistry, California Nano Systems Institute, University of California - Los Angeles, 420 Westwood Plaza, Room 5121 Engineering V, Los Angeles, CA, 90095, USA
| | - Mahmoud Nametalla
- Department of Biology, Brooklyn College, Room 307NE, 2900 Bedford Ave., Brooklyn, NY, 11210, USA
- CUNY Graduate Center, 365 5th Ave., New York, NY, 10016, USA
| | - Aneesa Valentine
- Department of Biology, Brooklyn College, Room 307NE, 2900 Bedford Ave., Brooklyn, NY, 11210, USA
- CUNY Graduate Center, 365 5th Ave., New York, NY, 10016, USA
| | - Benjamin Crair
- Department of Microbial Pathogenesis, Yale University, 840 West Campus Drive, Advanced Biosciences Center 211, West Haven, CT, 06516, USA
| | - Shiwei Zhu
- Department of Microbial Pathogenesis, Yale University, 840 West Campus Drive, Advanced Biosciences Center 211, West Haven, CT, 06516, USA
| | - Hannah Q Hughes
- Department of Biology, Indiana University - Bloomington, 1001 East Third St., Jordan Hall 469A, Bloomington, IN, 47405, USA
| | - Jennifer L Chlebek
- Department of Biology, Indiana University - Bloomington, 1001 East Third St., Jordan Hall 469A, Bloomington, IN, 47405, USA
| | - Daniel C Wu
- Department of Microbiology and Environmental Toxicology, University of California - Santa Cruz, 1156 High St., BioMed 245, Santa Cruz, CA, 95064, USA
| | - Jin Hwan Park
- Department of Microbiology and Environmental Toxicology, University of California - Santa Cruz, 1156 High St., BioMed 245, Santa Cruz, CA, 95064, USA
| | - Ali M Farhat
- Departments of Bioengineering, Chemistry and Biochemistry, California Nano Systems Institute, University of California - Los Angeles, 420 Westwood Plaza, Room 5121 Engineering V, Los Angeles, CA, 90095, USA
| | - Charles J Lomba
- Departments of Bioengineering, Chemistry and Biochemistry, California Nano Systems Institute, University of California - Los Angeles, 420 Westwood Plaza, Room 5121 Engineering V, Los Angeles, CA, 90095, USA
| | - Courtney K Ellison
- Department of Biology, Indiana University - Bloomington, 1001 East Third St., Jordan Hall 469A, Bloomington, IN, 47405, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, 355 Thomas Laboratory, Washington Road, Princeton, NJ, 08544, USA
| | - Yves V Brun
- Department of Microbiology, Infectious Diseases, and Immunology, Faculty of Medicine, University of Montreal, Pavillon Roger-Gaudry, 2900, boulevard Édouard-Montpetit, C.P. 6128, Succursale Centre-ville, Montréal, QC, H3C 3J7, Canada
| | - Javier Campos-Gomez
- Cystic Fibrosis Research Center, University of Alabama at Birmingham, 1918 University Blvd., MCLM 702, Birmingham, AL, 35233, USA
| | - Ankur B Dalia
- Department of Biology, Indiana University - Bloomington, 1001 East Third St., Jordan Hall 469A, Bloomington, IN, 47405, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University, 840 West Campus Drive, Advanced Biosciences Center 211, West Haven, CT, 06516, USA
| | - Nicolas Biais
- Department of Biology, Brooklyn College, Room 307NE, 2900 Bedford Ave., Brooklyn, NY, 11210, USA
- CUNY Graduate Center, 365 5th Ave., New York, NY, 10016, USA
| | - Gerard C L Wong
- Departments of Bioengineering, Chemistry and Biochemistry, California Nano Systems Institute, University of California - Los Angeles, 420 Westwood Plaza, Room 5121 Engineering V, Los Angeles, CA, 90095, USA.
| | - Fitnat H Yildiz
- Department of Microbiology and Environmental Toxicology, University of California - Santa Cruz, 1156 High St., BioMed 245, Santa Cruz, CA, 95064, USA.
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Han S, Shen D, Wang Y, Chou S, Gomelsky M, Gao Y, Qian G. A YajQ-LysR-like, cyclic di-GMP-dependent system regulating biosynthesis of an antifungal antibiotic in a crop-protecting bacterium, Lysobacter enzymogenes. MOLECULAR PLANT PATHOLOGY 2020; 21:218-229. [PMID: 31747123 PMCID: PMC6988422 DOI: 10.1111/mpp.12890] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
YajQ, a binding protein of the universal bacterial second messenger cyclic di-GMP (c-di-GMP), affects virulence in several bacterial pathogens, including Xanthomonas campestris. In this bacterium, YajQ interacts with the transcription factor LysR. Upon c-di-GMP binding, the whole c-di-GMP-YajQ-LysR complex is found to dissociate from DNA, resulting in virulence gene regulation. Here, we identify a YajQ-LysR-like system in the bacterial biocontrol agent Lysobacter enzymogenes OH11 that secretes an antifungal antibiotic, heat-stable antifungal factor (HSAF) against crop fungal pathogens. We show that the YajQ homologue, CdgL (c-di-GMP receptor interacting with LysR) affects expression of the HSAF biosynthesis operon by interacting with the transcription activator LysR. The CdgL-LysR interaction enhances the apparent affinity of LysR to the promoter region upstream of the HSAF biosynthesis operon, which increases operon expression. Unlike the homologues CdgL (YajQ)-LysR system in X. campestris, we show that c-di-GMP binding to CdgL seems to weaken CdgL-LysR interactions and promote the release of CdgL from the LysR-DNA complex, which leads to decreased expression. Together, this study takes the YajQ-LysR-like system from bacterial pathogens to a crop-protecting bacterium that is able to regulate antifungal HSAF biosynthesis via disassembly of the c-di-GMP receptor-transcription activator complex.
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Affiliation(s)
- Sen Han
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjing210095P.R. China
| | - Danyu Shen
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjing210095P.R. China
| | - Yu‐Chuan Wang
- Institute of Biochemistry, and NCHU Agricultural Biotechnology CenterNational Chung Hsing UniversityTaichungTaiwan
| | - Shan‐Ho Chou
- Institute of Biochemistry, and NCHU Agricultural Biotechnology CenterNational Chung Hsing UniversityTaichungTaiwan
| | - Mark Gomelsky
- Department of Molecular BiologyUniversity of WyomingLaramieWyoming82071USA
| | - Yong‐Gui Gao
- School of Biological SciencesNanyang Technological University60 Nanyang DriveSingapore637551Singapore
| | - Guoliang Qian
- College of Plant Protection (Key Laboratory of Integrated Management of Crop Diseases and Pests)Nanjing Agricultural UniversityNanjing210095P.R. China
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Abstract
Surface sensing is a fundamental yet poorly understood behavior of swimming bacteria. In this issue of Cell Host & Microbe, Laventie et al. (2019) describe a cyclic-di-GMP-dependent pathway used by the opportunistic pathogen Pseudomonas aeruginosa to respond to surface binding on a several second timescale.
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Affiliation(s)
- Ruchi Jain
- Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA
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Factors Controlling Floc Formation and Structure in the Cyanobacterium Synechocystis sp. Strain PCC 6803. J Bacteriol 2019; 201:JB.00344-19. [PMID: 31262837 PMCID: PMC6755745 DOI: 10.1128/jb.00344-19] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 06/25/2019] [Indexed: 02/07/2023] Open
Abstract
Motile strains of the unicellular cyanobacterium Synechocystis sp. strain PCC 6803 readily aggregate into flocs, or floating multicellular assemblages, when grown in liquid culture. As described here, we used confocal imaging to probe the structure of these flocs, and we developed a quantitative assay for floc formation based on fluorescence imaging of 6-well plates. The flocs are formed from strands of linked cells, sometimes packed into dense clusters but also containing voids with very few cells. Cells within the dense clusters show signs of nutrient stress, as judged by the subcellular distribution of green fluorescent protein (GFP)-tagged Vipp1 protein. We analyzed the effects on flocculation of a series of mutations that alter piliation and motility, including Δhfq, ΔpilB1, ΔpilT1, and ΔushA mutations and deletion mutations affecting major and minor pilins. The extent of flocculation is increased in the hyperpiliated ΔpilT1 mutant, but active cycles of pilus extension and retraction are not required for flocculation. Deletion of PilA1, the major subunit of type IV pili, has no effect on flocculation; however, flocculation is lost in mutants lacking an operon coding for the minor pilins PilA9 to -11. Therefore, minor pilins appear crucial for flocculation. We show that flocculation is a tightly regulated process that is promoted by blue light perception by the cyanobacteriochrome Cph2. Floc formation also seems to be a highly cooperative process. A proportion of nonflocculating Δhfq cells can be incorporated into wild-type flocs, but the presence of a high proportion of Δhfq cells disrupts the large-scale architecture of the floc.IMPORTANCE Some bacteria form flocs, which are multicellular floating assemblages of many thousands of cells. Flocs have been relatively little studied compared to surface-adherent biofilms, but flocculation could play many physiological roles, be a crucial factor in marine carbon burial, and enable more efficient biotechnological cell harvesting. We studied floc formation and architecture in the model cyanobacterium Synechocystis sp. strain PCC 6803, using mutants to identify specific cell surface structures required for floc formation. We show that floc formation is regulated by blue and green light perceived by the photoreceptor Cph2. The flocs have a characteristic structure based on strands of linked cells aggregating into dense clusters. Cells within the dense clusters show signs of nutrient stress, pointing to a disadvantage of floc formation.
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Alviz-Gazitua P, Fuentes-Alburquenque S, Rojas LA, Turner RJ, Guiliani N, Seeger M. The Response of Cupriavidus metallidurans CH34 to Cadmium Involves Inhibition of the Initiation of Biofilm Formation, Decrease in Intracellular c-di-GMP Levels, and a Novel Metal Regulated Phosphodiesterase. Front Microbiol 2019; 10:1499. [PMID: 31338076 PMCID: PMC6629876 DOI: 10.3389/fmicb.2019.01499] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 06/14/2019] [Indexed: 11/21/2022] Open
Abstract
Cadmium is a highly toxic heavy metal for biological systems. Cupriavidus metallidurans CH34 is a model strain to study heavy metal resistance and bioremediation as it is able to deal with high heavy metal concentrations. Biofilm formation by bacteria is mediated by the second messenger bis-(3′–5′)-cyclic dimeric guanosine monophosphate (c-di-GMP). The aim of this study was to characterize the response of C. metallidurans CH34 planktonic and biofilm cells to cadmium including their c-di-GMP regulatory pathway. Inhibition of the initiation of biofilm formation and EPS production by C. metallidurans CH34 correlates with increased concentration of cadmium. Planktonic and biofilm cells showed similar tolerance to cadmium. During exposure to cadmium an acute decrease of c-di-GMP levels in planktonic and biofilm cells was observed. Transcription analysis by RT-qPCR showed that cadmium exposure to planktonic and biofilm cells induced the expression of the urf2 gene and the mercuric reductase encoding merA gene, which belong to the Tn501/Tn21 mer operon. After exposure to cadmium, the cadA gene involved in cadmium resistance was equally upregulated in both lifestyles. Bioinformatic analysis and complementation assays indicated that the protein encoded by the urf2 gene is a functional phosphodiesterase (PDE) involved in the c-di-GMP metabolism. We propose to rename the urf2 gene as mrp gene for metal regulated PDE. An increase of the second messenger c-di-GMP content by the heterologous expression of the constitutively active diguanylate cyclase PleD correlated with an increase in biofilm formation and cadmium susceptibility. These results indicate that the response to cadmium in C. metallidurans CH34 inhibits the initiation of biofilm lifestyle and involves a decrease in c-di-GMP levels and a novel metal regulated PDE.
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Affiliation(s)
- Pablo Alviz-Gazitua
- Laboratorio de Comunicación Bacteriana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile.,Ph.D. Program of Microbiology, Faculty of Sciences, University of Chile, Santiago, Chile
| | - Sebastián Fuentes-Alburquenque
- Microbial Ecology of Extreme Systems Laboratory, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago, Chile
| | - Luis A Rojas
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile.,Department of Chemistry, Universidad Catoìlica del Norte, Antofagasta, Chile
| | - Raymond J Turner
- Biofilm Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Nicolas Guiliani
- Laboratorio de Comunicación Bacteriana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Michael Seeger
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile
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38
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Abstract
Bacterial surface attachment is mediated by filamentous appendages called pili. Here, we describe the role of Tad pili during surface colonization of Caulobacter crescentus Using an optical trap and microfluidic controlled flow conditions to mimic natural environments, we demonstrated that Tad pili undergo repeated dynamic cycles of extension and retraction. Within seconds after establishing surface contact, pilus retraction reorients cells into an upright position, promoting walking-like movements against the medium flow. Pilus-mediated positioning of the flagellate pole close to the surface facilitates motor-mediated mechanical sensing and promotes anchoring of the holdfast, an adhesive substance that affords long-term attachment. We present evidence that the second messenger c-di-GMP regulates pilus dynamics during surface encounter in distinct ways, promoting increased activity at intermediate levels and retraction of pili at peak concentrations. We propose a model in which flagellum and Tad pili functionally interact and together impose a ratchet-like mechanism that progressively drives C. crescentus cells toward permanent surface attachment.IMPORTANCE Bacteria are able to colonize surfaces in environmental, industrial, and medical settings, where they form resilient communities called biofilms. In order to control bacterial surface colonization, microbiologists need to gain a detailed understanding of the processes that bacteria use to live at the liquid-surface interface and that allow them to adhere to and move on surfaces and eventually grow and persist on solid media. To facilitate these processes, bacteria are equipped with adhesive structures such as flagella and pili and with matrix components such as exopolysaccharides. How these cellular organelles are coordinated to optimize surface processes is currently subject to intense investigations. Here we used the model organism Caulobacter crescentus to demonstrate that polar pili are highly dynamic structures that are functionally interconnected with the flagellar motor to mediate surface sensing, thereby enforcing rapid and permanent surface attachment. These studies provide an entry point for an in-depth molecular analysis of bacterial surface colonization.
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Armbruster CR, Lee CK, Parker-Gilham J, de Anda J, Xia A, Zhao K, Murakami K, Tseng BS, Hoffman LR, Jin F, Harwood CS, Wong GCL, Parsek MR. Heterogeneity in surface sensing suggests a division of labor in Pseudomonas aeruginosa populations. eLife 2019; 8:e45084. [PMID: 31180327 PMCID: PMC6615863 DOI: 10.7554/elife.45084] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 06/08/2019] [Indexed: 12/27/2022] Open
Abstract
The second messenger signaling molecule cyclic diguanylate monophosphate (c-di-GMP) drives the transition between planktonic and biofilm growth in many bacterial species. Pseudomonas aeruginosa has two surface sensing systems that produce c-di-GMP in response to surface adherence. Current thinking in the field is that once cells attach to a surface, they uniformly respond by producing c-di-GMP. Here, we describe how the Wsp system generates heterogeneity in surface sensing, resulting in two physiologically distinct subpopulations of cells. One subpopulation has elevated c-di-GMP and produces biofilm matrix, serving as the founders of initial microcolonies. The other subpopulation has low c-di-GMP and engages in surface motility, allowing for exploration of the surface. We also show that this heterogeneity strongly correlates to surface behavior for descendent cells. Together, our results suggest that after surface attachment, P. aeruginosa engages in a division of labor that persists across generations, accelerating early biofilm formation and surface exploration.
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Affiliation(s)
| | - Calvin K Lee
- Department of BioengineeringUniversity of California, Los AngelesLos AngelesUnited States
- Department of Chemistry and BiochemistryUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
| | | | - Jaime de Anda
- Department of BioengineeringUniversity of California, Los AngelesLos AngelesUnited States
- Department of Chemistry and BiochemistryUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
| | - Aiguo Xia
- Hefei National Laboratory for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefeiChina
| | - Kun Zhao
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and TechnologyTianjin UniversityTianjinChina
- Collaborative Innovation Centre of Chemical Science and EngineeringTianjin UniversityTianjinChina
| | - Keiji Murakami
- Department of Oral Microbiology, Institute of Biomedical SciencesTokushima University Graduate SchoolTokushimaJapan
| | - Boo Shan Tseng
- School of Life SciencesUniversity of NevadaLas VegasUnited States
| | - Lucas R Hoffman
- Department of MicrobiologyUniversity of WashingtonSeattleUnited States
- Department of PediatricsUniversity of WashingtonSeattleUnited States
| | - Fan Jin
- Hefei National Laboratory for Physical Sciences at the MicroscaleUniversity of Science and Technology of ChinaHefeiChina
- Institute of Synthetic BiologyShenzhen Institutes of Advanced Technology, Chinese Academy of SciencesShenzhenChina
| | | | - Gerard CL Wong
- Department of BioengineeringUniversity of California, Los AngelesLos AngelesUnited States
- Department of Chemistry and BiochemistryUniversity of California, Los AngelesLos AngelesUnited States
- California NanoSystems InstituteUniversity of California, Los AngelesLos AngelesUnited States
| | - Matthew R Parsek
- Department of MicrobiologyUniversity of WashingtonSeattleUnited States
- Integrative Microbiology Research CentreSouth China Agricultural UniversityGuangzhouChina
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40
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Abstract
Type IV pilus (T4P)-like systems have been identified in almost every major phylum of prokaryotic life. They include the type IVa pilus (T4aP), type II secretion system (T2SS), type IVb pilus (T4bP), Tad/Flp pilus, Com pilus, and archaeal flagellum (archaellum). These systems are used for adhesion, natural competence, phage adsorption, folded-protein secretion, surface sensing, swimming motility, and twitching motility. The T4aP allows for all of these functions except swimming and is therefore a good model system for understanding T4P-like systems. Recent structural analyses have revolutionized our understanding of how the T4aP machinery assembles and functions. Here we review the structure and function of the T4aP.
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41
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Laventie BJ, Sangermani M, Estermann F, Manfredi P, Planes R, Hug I, Jaeger T, Meunier E, Broz P, Jenal U. A Surface-Induced Asymmetric Program Promotes Tissue Colonization by Pseudomonas aeruginosa. Cell Host Microbe 2018; 25:140-152.e6. [PMID: 30581112 DOI: 10.1016/j.chom.2018.11.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/28/2018] [Accepted: 10/22/2018] [Indexed: 12/24/2022]
Abstract
The opportunistic human pathogen Pseudomonas aeruginosa effectively colonizes host epithelia using pili as primary adhesins. Here we uncover a surface-specific asymmetric virulence program that enhances P. aeruginosa host colonization. We show that when P. aeruginosa encounters surfaces, the concentration of the second messenger c-di-GMP increases within a few seconds. This leads to surface adherence and virulence induction by stimulating pili assembly through activation of the c-di-GMP receptor FimW. Surface-attached bacteria divide asymmetrically to generate a piliated, surface-committed progeny (striker) and a flagellated, motile offspring that leaves the surface to colonize distant sites (spreader). Cell differentiation is driven by a phosphodiesterase that asymmetrically positions to the flagellated pole, thereby maintaining c-di-GMP levels low in the motile offspring. Infection experiments demonstrate that cellular asymmetry strongly boosts infection spread and tissue damage. Thus, P. aeruginosa promotes surface colonization and infection transmission through a cooperative virulence program that we termed Touch-Seed-and-Go.
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Affiliation(s)
| | - Matteo Sangermani
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Fabienne Estermann
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Pablo Manfredi
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | | | - Isabelle Hug
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Tina Jaeger
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | | | - Petr Broz
- Department of Biochemistry, University of Lausanne, Lausanne, Switzerland
| | - Urs Jenal
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland.
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42
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Nolan LM, Whitchurch CB, Barquist L, Katrib M, Boinett CJ, Mayho M, Goulding D, Charles IG, Filloux A, Parkhill J, Cain AK. A global genomic approach uncovers novel components for twitching motility-mediated biofilm expansion in Pseudomonas aeruginosa. Microb Genom 2018; 4. [PMID: 30383525 PMCID: PMC6321873 DOI: 10.1099/mgen.0.000229] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas aeruginosa is an extremely successful pathogen able to cause both acute and chronic infections in a range of hosts, utilizing a diverse arsenal of cell-associated and secreted virulence factors. A major cell-associated virulence factor, the Type IV pilus (T4P), is required for epithelial cell adherence and mediates a form of surface translocation termed twitching motility, which is necessary to establish a mature biofilm and actively expand these biofilms. P. aeruginosa twitching motility-mediated biofilm expansion is a coordinated, multicellular behaviour, allowing cells to rapidly colonize surfaces, including implanted medical devices. Although at least 44 proteins are known to be involved in the biogenesis, assembly and regulation of the T4P, with additional regulatory components and pathways implicated, it is unclear how these components and pathways interact to control these processes. In the current study, we used a global genomics-based random-mutagenesis technique, transposon directed insertion-site sequencing (TraDIS), coupled with a physical segregation approach, to identify all genes implicated in twitching motility-mediated biofilm expansion in P. aeruginosa. Our approach allowed identification of both known and novel genes, providing new insight into the complex molecular network that regulates this process in P. aeruginosa. Additionally, our data suggest that the flagellum-associated gene products have a differential effect on twitching motility, based on whether components are intra- or extracellular. Overall the success of our TraDIS approach supports the use of this global genomic technique for investigating virulence genes in bacterial pathogens.
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Affiliation(s)
- Laura M Nolan
- 1MRC Centre for Molecular Bacteriology and Infection (CMBI), Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Cynthia B Whitchurch
- 2The ithree Institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Lars Barquist
- 3Institute for Molecular Infection Biology, University of Würzburg, Würzburg D-97080, Germany.,4Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
| | - Marilyn Katrib
- 2The ithree Institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Christine J Boinett
- 5Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK.,†Present address: Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Matthew Mayho
- 5Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - David Goulding
- 5Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Ian G Charles
- 6Quadram Institute of Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UA, UK
| | - Alain Filloux
- 1MRC Centre for Molecular Bacteriology and Infection (CMBI), Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Julian Parkhill
- 5Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Amy K Cain
- 5Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK.,‡Present address: Chemical and Biomolecular Sciences, Macquarie University, Sydney, NSW, Australia
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43
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Tusk SE, Delalez NJ, Berry RM. Subunit Exchange in Protein Complexes. J Mol Biol 2018; 430:4557-4579. [DOI: 10.1016/j.jmb.2018.06.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/21/2018] [Accepted: 06/21/2018] [Indexed: 01/09/2023]
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44
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Solanki V, Kapoor S, Thakur KG. Structural insights into the mechanism of Type IVa pilus extension and retraction ATPase motors. FEBS J 2018; 285:3402-3421. [PMID: 30066435 DOI: 10.1111/febs.14619] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/26/2018] [Accepted: 07/30/2018] [Indexed: 11/27/2022]
Abstract
Type IVa pili are bacterial appendages involved in diverse physiological processes, including electron transfer in Geobacter sulfurreducens. ATP hydrolysis coupled with conformational changes powers the extension (PilB) and retraction (PilT) motors in the pilus machinery. We report the unliganded crystal structures of the core ATPase domain of PilB and PilT-4 from G. sulfurreducens at 3.1 and 2.6 Å resolution, respectively. PilB structure revealed three distinct conformations, that is, open, closed, and open' which were previously proposed to be mediated by ATP/ADP binding. PilT-4 subunits, on the other hand, were observed in the closed state conformation. We further report that both PilB and PilT-4 hexamers have two high-affinity ATP-binding sites. Comparative structural analysis and solution data presented here supports the "symmetric rotary model" for these ATPase motors. Our data further suggest that pores of these motors rotate either clockwise or counterclockwise to facilitate assembly or disassembly of right-handed or left-handed pilus. DATABASE Structural data are available in the RCSB PDB database under the PDB ID 5ZFQ (PilT-4), 5ZFR (PilB).
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Affiliation(s)
- Vipul Solanki
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh, India
| | - Srajan Kapoor
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh, India
| | - Krishan Gopal Thakur
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh, India
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45
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The type IV pilus assembly motor PilB is a robust hexameric ATPase with complex kinetics. Biochem J 2018; 475:1979-1993. [PMID: 29717025 DOI: 10.1042/bcj20180167] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/23/2018] [Accepted: 05/01/2018] [Indexed: 01/06/2023]
Abstract
The bacterial type IV pilus (T4P) is a versatile nanomachine that functions in pathogenesis, biofilm formation, motility, and horizontal gene transfer. T4P assembly is powered by the motor ATPase PilB which is proposed to hydrolyze ATP by a symmetrical rotary mechanism. This mechanism, which is deduced from the structure of PilB, is untested. Here, we report the first kinetic studies of the PilB ATPase, supporting co-ordination among the protomers of this hexameric enzyme. Analysis of the genome sequence of Chloracidobacterium thermophilum identified a pilB gene whose protein we then heterologously expressed. This PilB formed a hexamer in solution and exhibited highly robust ATPase activity. It displays complex steady-state kinetics with an incline followed by a decline over an ATP concentration range of physiological relevance. The incline is multiphasic and the decline signifies substrate inhibition. These observations suggest that variations in intracellular ATP concentrations may regulate T4P assembly and T4P-mediated functions in vivo in accordance with the physiological state of bacteria with unanticipated complexity. We also identified a mutant pilB gene in the genomic DNA of C. thermophilum from an enrichment culture. The mutant PilB variant, which is significantly less active, exhibited similar inhibition of its ATPase activity by high concentrations of ATP. Our findings here with the PilB ATPase from C. thermophilum provide the first line of biochemical evidence for the co-ordination among PilB protomers consistent with the symmetrical rotary model of catalysis based on structural studies.
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46
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Chang CY. Surface Sensing for Biofilm Formation in Pseudomonas aeruginosa. Front Microbiol 2018; 8:2671. [PMID: 29375533 PMCID: PMC5767216 DOI: 10.3389/fmicb.2017.02671] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/21/2017] [Indexed: 11/13/2022] Open
Abstract
Aggregating and forming biofilms on biotic or abiotic surfaces are ubiquitous bacterial behaviors under various conditions. In clinical settings, persistent presence of biofilms increases the risks of healthcare-associated infections and imposes huge healthcare and economic burdens. Bacteria within biofilms are protected from external damage and attacks from the host immune system and can exchange genomic information including antibiotic-resistance genes. Dispersed bacterial cells from attached biofilms on medical devices or host tissues may also serve as the origin of further infections. Understanding how bacteria develop biofilms is pertinent to tackle biofilm-associated infections and transmission. Biofilms have been suggested as a continuum of growth modes for adapting to different environments, initiating from bacterial cells sensing their attachment to a surface and then switching cellular physiological status for mature biofilm development. It is crucial to understand bacterial gene regulatory networks and decision-making processes for biofilm formation upon initial surface attachment. Pseudomonas aeruginosa is one of the model microorganisms for studying bacterial population behaviors. Several hypotheses and studies have suggested that extracellular macromolecules and appendages play important roles in bacterial responses to the surface attachment. Here, I review recent studies on potential molecular mechanisms and signal transduction pathways for P. aeruginosa surface sensing.
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Affiliation(s)
- Chien-Yi Chang
- School of Chemistry and Biosciences, University of Bradford, Bradford, United Kingdom
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