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Gerken H, Shetty D, Kern B, Kenney LJ, Misra R. Effects of pleiotropic ompR and envZ alleles of Escherichia coli on envelope stress and antibiotic sensitivity. J Bacteriol 2024; 206:e0017224. [PMID: 38809006 PMCID: PMC11332150 DOI: 10.1128/jb.00172-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 05/06/2024] [Indexed: 05/30/2024] Open
Abstract
The EnvZ-OmpR two-component system of Escherichia coli regulates the expression of the ompF and ompC porin genes in response to medium osmolarity. However, certain mutations in envZ confer pleiotropy by affecting the expression of genes of the iron and maltose regulons not normally controlled by EnvZ-OmpR. In this study, we obtained two novel envZ and ompR pleiotropic alleles, envZT15P and ompRL19Q, among revertants of a mutant with heightened envelope stress and an outer membrane (OM) permeability defect. Unlike envZ, pleiotropic mutations in ompR have not been described previously. The mutant alleles reduced the expression of several outer membrane proteins (OMPs), overcame the temperature-sensitive growth defect of a protease-deficient (ΔdegP) strain, and lowered envelope stress and OM permeability defects in a background lacking the BamB protein of an essential β-barrel assembly machinery complex. Biochemical analysis showed OmpRL19Q, like wild-type OmpR, is readily phosphorylated by EnvZ, but the EnvZ-dependent dephosphorylation of OmpRL19Q~P was drastically impaired compared to wild-type OmpR. This defect would lead to a prolonged half-life for OmpRL19Q~P, an outcome remarkably similar to what we had previously described for EnvZR397L, resulting in pleiotropy. By employing null alleles of the OMP genes, it was determined that the three pleiotropic alleles lowered envelope stress by reducing OmpF and LamB levels. The absence of LamB was principally responsible for lowering the OM permeability defect, as assessed by the reduced sensitivity of a ΔbamB mutant to vancomycin and rifampin. Possible mechanisms by which novel EnvZ and OmpR mutants influence EnvZ-OmpR interactions and activities are discussed.IMPORTANCEMaintenance of the outer membrane (OM) integrity is critical for the survival of Gram-negative bacteria. Several envelope homeostasis systems are activated when OM integrity is perturbed. Through the isolation and characterization of novel pleiotropic ompR/envZ alleles, this study highlights the involvement of the EnvZ-OmpR two-component system in lowering envelope stress and the OM permeability defect caused by the loss of proteins that are involved in OM biogenesis, envelope homeostasis, and structural integrity.
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Affiliation(s)
- Henri Gerken
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Dasvit Shetty
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA
| | - Brea Kern
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Linda J. Kenney
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Rajeev Misra
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
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Zhao Q, Yao F, Li W, Liu S, Bi S. Identification of a dCache-type chemoreceptor in Campylobacter jejuni that specifically mediates chemotaxis towards methyl pyruvate. Front Microbiol 2024; 15:1400284. [PMID: 38784811 PMCID: PMC11111895 DOI: 10.3389/fmicb.2024.1400284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 04/25/2024] [Indexed: 05/25/2024] Open
Abstract
The foodborne pathogenic bacterium Campylobacter jejuni utilizes chemotaxis to assist in the colonization of host niches. A key to revealing the relationship among chemotaxis and pathogenicity is the discovery of signaling molecules perceived by the chemoreceptors. The C. jejuni chemoreceptor Tlp11 is encoded by the highly infective C. jejuni strains. In the present study, we report that the dCache-type ligand-binding domain (LBD) of C. jejuni ATCC 33560 Tlp11 binds directly to novel ligands methyl pyruvate, toluene, and quinoline using the same pocket. Methyl pyruvate elicits a strong chemoattractant response, while toluene and quinoline function as the antagonists without triggering chemotaxis. The sensory LBD was used to control heterologous proteins by constructing chimeras, indicating that the signal induced by methyl pyruvate is transmitted across the membrane. In addition, bioinformatics and experiments revealed that the dCache domains with methyl pyruvate-binding sites and ability are widely distributed in the order Campylobacterales. This is the first report to identify the class of dCache chemoreceptors that bind to attractant methyl pyruvate and antagonists toluene and quinoline. Our research provides a foundation for understanding the chemotaxis and virulence of C. jejuni and lays a basis for the control of this foodborne pathogen.
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Affiliation(s)
- Qi Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Fulian Yao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Wei Li
- Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, China
| | - Shuangjiang Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- State Key Laboratory of Microbial Resources, and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Shuangyu Bi
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
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3
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Kenney LJ. Peeling the onion: additional layers of regulation in the acid stress response. J Bacteriol 2024; 206:e0006924. [PMID: 38488356 PMCID: PMC11025319 DOI: 10.1128/jb.00069-24] [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] [Indexed: 04/19/2024] Open
Abstract
Bacteria are capable of withstanding large changes in osmolality and cytoplasmic pH, unlike eukaryotes that tightly regulate their pH and cellular composition. Previous studies on the bacterial acid stress response described a rapid, brief acidification, followed by immediate recovery. More recent experiments with better pH probes have imaged single living cells, and we now appreciate that following acid stress, bacteria maintain an acidic cytoplasm for as long as the stress remains. This acidification enables pathogens to sense a host environment and turn on their virulence programs, for example, enabling survival and replication within acidic vacuoles. Single-cell analysis identified an intracellular pH threshold of ~6.5. Acid stress reduces the internal pH below this threshold, triggering the assembly of a type III secretion system in Salmonella and the secretion of virulence factors in the host. These pathways are significant because preventing intracellular acidification of Salmonella renders it avirulent, suggesting that acid stress pathways represent a potential therapeutic target. Although we refer to the acid stress response as singular, it is actually a complex response that involves numerous two-component signaling systems, several amino acid decarboxylation systems, as well as cellular buffering systems and electron transport chain components, among others. In a recent paper in the Journal of Bacteriology, M. G. Gorelik, H. Yakhnin, A. Pannuri, A. C. Walker, C. Pourciau, D. Czyz, T. Romeo, and P. Babitzke (J Bacteriol 206:e00354-23, 2024, https://doi.org/10.1128/jb.00354-23) describe a new connection linking the carbon storage regulator CsrA to the acid stress response, highlighting new additional layers of complexity.
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Affiliation(s)
- Linda J. Kenney
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch Galveston, Galveston, Texas, USA
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4
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Song Y, Wu X, Li Z, Ma QQ, Bao R. Molecular mechanism of siderophore regulation by the Pseudomonas aeruginosa BfmRS two-component system in response to osmotic stress. Commun Biol 2024; 7:295. [PMID: 38461208 PMCID: PMC10924945 DOI: 10.1038/s42003-024-05995-z] [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: 11/13/2023] [Accepted: 02/29/2024] [Indexed: 03/11/2024] Open
Abstract
Pseudomonas aeruginosa, a common nosocomial pathogen, relies on siderophores to acquire iron, crucial for its survival in various environments and during host infections. However, understanding the molecular mechanisms of siderophore regulation remains incomplete. In this study, we found that the BfmRS two-component system, previously associated with biofilm formation and quorum sensing, is essential for siderophore regulation under high osmolality stress. Activated BfmR directly bound to the promoter regions of pvd, fpv, and femARI gene clusters, thereby activating their transcription and promoting siderophore production. Subsequent proteomic and phenotypic analyses confirmed that deletion of BfmRS reduces siderophore-related proteins and impairs bacterial survival in iron-deficient conditions. Furthermore, phylogenetic analysis demonstrated the high conservation of the BfmRS system across Pseudomonas species, functional evidences also indicated that BfmR homologues from Pseudomonas putida KT2440 and Pseudomonas sp. MRSN12121 could bind to the promoter regions of key siderophore genes and osmolality-mediated increases in siderophore production were observed. This work illuminates a novel signaling pathway for siderophore regulation and enhances our understanding of siderophore-mediated bacterial interactions and community establishment.
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Affiliation(s)
- Yingjie Song
- College of Life Science, Sichuan Normal University, Chengdu, 610101, China
| | - Xiyu Wu
- Advanced Mass Spectrometry Center, Research Core Facility, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, 610213, China
| | - Ze Li
- Center of Infectious Diseases, Division of Infectious Diseases in State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Qin Qin Ma
- College of Life Science, Sichuan Normal University, Chengdu, 610101, China
| | - Rui Bao
- Center of Infectious Diseases, Division of Infectious Diseases in State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.
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5
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Barretto LAF, Van PKT, Fowler CC. Conserved patterns of sequence diversification provide insight into the evolution of two-component systems in Enterobacteriaceae. Microb Genom 2024; 10:001215. [PMID: 38502064 PMCID: PMC11004495 DOI: 10.1099/mgen.0.001215] [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: 11/29/2023] [Accepted: 02/29/2024] [Indexed: 03/20/2024] Open
Abstract
Two-component regulatory systems (TCSs) are a major mechanism used by bacteria to sense and respond to their environments. Many of the same TCSs are used by biologically diverse organisms with different regulatory needs, suggesting that the functions of TCS must evolve. To explore this topic, we analysed the amino acid sequence divergence patterns of a large set of broadly conserved TCS across different branches of Enterobacteriaceae, a family of Gram-negative bacteria that includes biomedically important genera such as Salmonella, Escherichia, Klebsiella and others. Our analysis revealed trends in how TCS sequences change across different proteins or functional domains of the TCS, and across different lineages. Based on these trends, we identified individual TCS that exhibit atypical evolutionary patterns. We observed that the relative extent to which the sequence of a given TCS varies across different lineages is generally well conserved, unveiling a hierarchy of TCS sequence conservation with EnvZ/OmpR as the most conserved TCS. We provide evidence that, for the most divergent of the TCS analysed, PmrA/PmrB, different alleles were horizontally acquired by different branches of this family, and that different PmrA/PmrB sequence variants have highly divergent signal-sensing domains. Collectively, this study sheds light on how TCS evolve, and serves as a compendium for how the sequences of the TCS in this family have diverged over the course of evolution.
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Affiliation(s)
- Luke A. F. Barretto
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G2E9, Canada
| | - Patryc-Khang T. Van
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G2E9, Canada
| | - Casey C. Fowler
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G2E9, Canada
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Wang Y, Li X, Zhang G, Bi J, Hou H. Transcriptome Reveals Regulation of Quorum Sensing of Hafnia alvei H4 on the Coculture System of Hafnia alvei H4 and Pseudomonas fluorescens ATCC13525. Foods 2024; 13:336. [PMID: 38275703 PMCID: PMC10815324 DOI: 10.3390/foods13020336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/16/2024] [Accepted: 01/19/2024] [Indexed: 01/27/2024] Open
Abstract
In the food industry, foodborne spoilage bacteria often live in mixed species and attach to each other, leading to changes in spoilage characteristics. Quorum sensing (QS) has been reported to be a regulating mechanism for food spoiling by certain kinds of bacteria. Here, the contents of biofilm, extracellular polysaccharides, and biogenic amines in the coculture system of Hafnia alvei H4 and Pseudomonas fluorescens ATCC13525 were significantly reduced when the QS element of H. alvei H4 was deleted, confirming that QS of H. alvei H4 is involved in the dual-species interactions. Then, transcriptomics was used to explore the regulatory mechanism at the mRNA molecular level. The deletion of the QS element decreased the transcript levels of genes related to chemotaxis, flagellar assembly, and the two-component system pathway of H. alvei H4 in the coculture system. Furthermore, a total of 732 DEGs of P. fluorescens ATCC13525 were regulated in the dual species, which were primarily concerned with biofilm formation, ATP-binding cassette transporters, and amino acid metabolism. Taken together, the absence of the QS element of H. alvei H4 weakened the mutual cooperation of the two bacteria in the coculture system, making it a good target for managing infection with H. alvei and P. fluorescens.
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Affiliation(s)
- Yanan Wang
- School of Food Science and Technology, Dalian Polytechnic University, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China; (Y.W.); (X.L.); (G.Z.); (J.B.)
- Liaoning Key Lab for Aquatic Processing Quality and Safety, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China
| | - Xue Li
- School of Food Science and Technology, Dalian Polytechnic University, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China; (Y.W.); (X.L.); (G.Z.); (J.B.)
- Liaoning Key Lab for Aquatic Processing Quality and Safety, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China
| | - Gongliang Zhang
- School of Food Science and Technology, Dalian Polytechnic University, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China; (Y.W.); (X.L.); (G.Z.); (J.B.)
- Liaoning Key Lab for Aquatic Processing Quality and Safety, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China
| | - Jingran Bi
- School of Food Science and Technology, Dalian Polytechnic University, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China; (Y.W.); (X.L.); (G.Z.); (J.B.)
- Liaoning Key Lab for Aquatic Processing Quality and Safety, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China
| | - Hongman Hou
- School of Food Science and Technology, Dalian Polytechnic University, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China; (Y.W.); (X.L.); (G.Z.); (J.B.)
- Liaoning Key Lab for Aquatic Processing Quality and Safety, No. 1 Qinggongyuan, Ganjingzi District, Dalian 116034, China
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7
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Janssen AB, de Bakker V, Aprianto R, Trebosc V, Kemmer C, Pieren M, Veening JW. Klebsiella pneumoniae OmpR facilitates lung infection through transcriptional regulation of key virulence factors. Microbiol Spectr 2024; 12:e0396623. [PMID: 38099618 PMCID: PMC10783089 DOI: 10.1128/spectrum.03966-23] [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: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 01/13/2024] Open
Abstract
IMPORTANCE Bacteria use two-component regulatory systems (TCSs) to adapt to changes in their environment by changing their gene expression. In this study, we show that the EnvZ/OmpR TCS of the clinically relevant opportunistic pathogen Klebsiella pneumoniae plays an important role in successfully establishing lung infection and virulence. In addition, we elucidate the K. pneumoniae OmpR regulon within the host. This work suggests that K. pneumoniae OmpR might be a promising target for innovative anti-infectives.
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Affiliation(s)
- Axel B. Janssen
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Vincent de Bakker
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Rieza Aprianto
- Molecular Genetics Group, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, Groningen, the Netherlands
| | | | | | | | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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8
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Chaves-Olarte E, Meza-Torres J, Herrera-Rodríguez F, Lizano-González E, Suárez-Esquivel M, Baker KS, Rivas-Solano O, Ruiz-Villalobos N, Villalta-Romero F, Cheng HP, Walker GC, Cloeckaert A, Thomson NR, Frisan T, Moreno E, Guzmán-Verri C. A sensor histidine kinase from a plant-endosymbiont bacterium restores the virulence of a mammalian intracellular pathogen. Microb Pathog 2023; 185:106442. [PMID: 37944675 PMCID: PMC10740080 DOI: 10.1016/j.micpath.2023.106442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 07/22/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023]
Abstract
Alphaproteobacteria include organisms living in close association with plants or animals. This interaction relies partly on orthologous two-component regulatory systems (TCS), with sensor and regulator proteins modulating the expression of conserved genes related to symbiosis/virulence. We assessed the ability of the exoS+Sm gene, encoding a sensor protein from the plant endosymbiont Sinorhizobium meliloti to substitute its orthologous bvrS in the related animal/human pathogen Brucella abortus. ExoS phosphorylated the B. abortus regulator BvrR in vitro and in cultured bacteria, showing conserved biological function. Production of ExoS in a B. abortus bvrS mutant reestablished replication in host cells and the capacity to infect mice. Bacterial outer membrane properties, the production of the type IV secretion system VirB, and its transcriptional regulators VjbR and BvrR were restored as compared to parental B. abortus. These results indicate that conserved traits of orthologous TCS from bacteria living in and sensing different environments are sufficient to achieve phenotypic plasticity and support bacterial survival. The knowledge of bacterial genetic networks regulating host interactions allows for an understanding of the subtle differences between symbiosis and parasitism. Rewiring these networks could provide new alternatives to control and prevent bacterial infection.
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Affiliation(s)
- Esteban Chaves-Olarte
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica; Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Jazmín Meza-Torres
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Fabiola Herrera-Rodríguez
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Esteban Lizano-González
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica; Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Marcela Suárez-Esquivel
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Kate S Baker
- Parasites and Microbes from Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK
| | - Olga Rivas-Solano
- Centro de Investigación en Biotecnología, Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica
| | - Nazareth Ruiz-Villalobos
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Fabián Villalta-Romero
- Centro de Investigación en Biotecnología, Escuela de Biología, Instituto Tecnológico de Costa Rica, Cartago, Costa Rica
| | - Hai-Ping Cheng
- Biological Sciences Department, Lehman College, The City University of New York, New York, USA
| | - Graham C Walker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Nicholas R Thomson
- Parasites and Microbes from Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK
| | - Teresa Frisan
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Edgardo Moreno
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Caterina Guzmán-Verri
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica; Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica.
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Tran T, Karunanayake Mudiyanselage APKK, Eyles SJ, Thompson LK. Bacterial chemoreceptor signaling complexes control kinase activity by stabilizing the catalytic domain of CheA. Proc Natl Acad Sci U S A 2023; 120:e2218467120. [PMID: 37523532 PMCID: PMC10410752 DOI: 10.1073/pnas.2218467120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 07/10/2023] [Indexed: 08/02/2023] Open
Abstract
Motile bacteria have a chemotaxis system that enables them to sense their environment and direct their swimming toward favorable conditions. Chemotaxis involves a signaling process in which ligand binding to the extracellular domain of the chemoreceptor alters the activity of the histidine kinase, CheA, bound ~300 Å away to the distal cytoplasmic tip of the receptor, to initiate a phosphorylation cascade that controls flagellar rotation. The cytoplasmic domain of the receptor is thought to propagate this signal via changes in dynamics and/or stability, but it is unclear how these changes modulate the kinase activity of CheA. To address this question, we have used hydrogen deuterium exchange mass spectrometry to probe the structure and dynamics of CheA within functional signaling complexes of the Escherichia coli aspartate receptor cytoplasmic fragment, CheA, and CheW. Our results reveal that stabilization of the P4 catalytic domain of CheA correlates with kinase activation. Furthermore, differences in activation of the kinase that occur during sensory adaptation depend on receptor destabilization of the P3 dimerization domain of CheA. Finally, hydrogen exchange properties of the P1 domain that bears the phosphorylated histidine identify the dimer interface of P1/P1' in the CheA dimer and support an ordered sequential binding mechanism of catalysis, in which dimeric P1/P1' has productive interactions with P4 only upon nucleotide binding. Thus stabilization/destabilization of domains is a key element of the mechanism of modulating CheA kinase activity in chemotaxis, and may play a role in the control of other kinases.
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Affiliation(s)
- Thomas Tran
- Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA01003
| | | | - Stephen J. Eyles
- Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA01003
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA01003
| | - Lynmarie K. Thompson
- Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA01003
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA01003
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10
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Laboratory evolution reveals general and specific tolerance mechanisms for commodity chemicals. Metab Eng 2023; 76:179-192. [PMID: 36738854 DOI: 10.1016/j.ymben.2023.01.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/06/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023]
Abstract
Although strain tolerance to high product concentrations is a barrier to the economically viable biomanufacturing of industrial chemicals, chemical tolerance mechanisms are often unknown. To reveal tolerance mechanisms, an automated platform was utilized to evolve Escherichia coli to grow optimally in the presence of 11 industrial chemicals (1,2-propanediol, 2,3-butanediol, glutarate, adipate, putrescine, hexamethylenediamine, butanol, isobutyrate, coumarate, octanoate, hexanoate), reaching tolerance at concentrations 60%-400% higher than initial toxic levels. Sequencing genomes of 223 isolates from 89 populations, reverse engineering, and cross-compound tolerance profiling were employed to uncover tolerance mechanisms. We show that: 1) cells are tolerized via frequent mutation of membrane transporters or cell wall-associated proteins (e.g., ProV, KgtP, SapB, NagA, NagC, MreB), transcription and translation machineries (e.g., RpoA, RpoB, RpoC, RpsA, RpsG, NusA, Rho), stress signaling proteins (e.g., RelA, SspA, SpoT, YobF), and for certain chemicals, regulators and enzymes in metabolism (e.g., MetJ, NadR, GudD, PurT); 2) osmotic stress plays a significant role in tolerance when chemical concentrations exceed a general threshold and mutated genes frequently overlap with those enabling chemical tolerance in membrane transporters and cell wall-associated proteins; 3) tolerization to a specific chemical generally improves tolerance to structurally similar compounds whereas a tradeoff can occur on dissimilar chemicals, and 4) using pre-tolerized starting isolates can hugely enhance the subsequent production of chemicals when a production pathway is inserted in many, but not all, evolved tolerized host strains, underpinning the need for evolving multiple parallel populations. Taken as a whole, this study provides a comprehensive genotype-phenotype map based on identified mutations and growth phenotypes for 223 chemical tolerant isolates.
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11
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Transcriptome Analysis Reveals the Effect of Low NaCl Concentration on Osmotic Stress and Type III Secretion System in Vibrio parahaemolyticus. Int J Mol Sci 2023; 24:ijms24032621. [PMID: 36768942 PMCID: PMC9916905 DOI: 10.3390/ijms24032621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/02/2023] [Accepted: 01/19/2023] [Indexed: 01/31/2023] Open
Abstract
Vibrio parahaemolyticus is a moderately halophilic foodborne pathogen that is mainly distributed in marine and freshwater environments. The transition of V. parahaemolyticus between aquatic ecosystems and hosts is essential for infection. Both freshwater and host environments have low salinity. In this study, we sought to further investigate the effects of low salinity (0.5% NaCl) on the fitness and virulence of V. parahaemolyticus. We found that V. parahaemolyticus could survive in Luria-Bertani (LB) and M9 mediums with different NaCl concentrations, except for the M9 medium containing 9% NaCl. Our results further showed that V. parahaemolyticus cultured in M9 medium with 0.5% NaCl had a higher cell density than that cultured at other NaCl concentrations when it entered the stationary phase. Therefore, we compared the transcriptomes of V. parahaemolyticus wild type (WT) cultured in an M9 medium with 0.5% and 3% NaCl at the stationary phase using RNA-seq. A total of 658 genes were significantly differentially expressed in the M9 medium with 0.5% NaCl, including regulators, osmotic adaptive responses (compatible solute synthesis systems, transporters, and outer membrane proteins), and virulence factors (T3SS1 and T6SS1). Furthermore, a low salinity concentration in the M9 medium induced the expression of T3SS1 to mediate the cytotoxicity of V. parahaemolyticus to HeLa cells. Similarly, low salinity could also induce the secretion of the T3SS2 translocon protein VPA1361. These factors may result in the high pathogenicity of V. parahaemolyticus in low-salinity environments. Taken together, these results suggest that low salinity (0.5% NaCl) could affect gene expression to mediate fitness and virulence, which may contribute to the transition of V. parahaemolyticus between aquatic ecosystems and the host.
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12
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Hyperosmotic stress allosterically reconfigures betaine binding pocket in BetP. J Mol Biol 2022; 434:167747. [PMID: 35870651 DOI: 10.1016/j.jmb.2022.167747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 12/18/2022]
Abstract
The transporter BetP in C. glutamicum is essential in maintaining bacterial cell viability during hyperosmotic stress and functions by co-transporting betaine and Na+ into bacterial cells. Hyperosmotic stress leads to increased intracellular K+ concentrations which in turn promotes betaine binding. While structural details of multiple end state conformations of BetP have provided high resolution snapshots, how K+ sensing by the C-terminal domain is allosterically relayed to the betaine binding site is not well understood. In this study, we describe conformational dynamics in solution of BetP using amide hydrogen/deuterium exchange mass spectrometry (HDXMS). These reveal how K+ alters conformation of the disordered C- and N-terminal domains to allosterically reconfigure transmembrane helices 3,8 and 10 (TM 3, 8, 10) to enhance betaine interactions. A map of the betaine binding site, at near single amino acid resolution, reveals a critical extrahelical H-bond mediated by TM3 with betaine.
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13
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Wang Q, Wang P, Liu P, Ou J. Comparative Transcriptome Analysis Reveals Regulatory Factors Involved in Vibrio Parahaemolyticus Biofilm Formation. Front Cell Infect Microbiol 2022; 12:917131. [PMID: 35899046 PMCID: PMC9309355 DOI: 10.3389/fcimb.2022.917131] [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: 04/10/2022] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
Vibrio parahaemolyticus biofilm poses a serious threat to food safety and human health. However, there is limited knowledge of transcriptional regulatory mechanism during the biofilm formation of this organism. Hence, the RNA sequencing technique was employed to compare the differences in transcriptome profiles between planktonic and biofilm state of V. parahaemolyticus ATCC33847 in this study. Collections of mRNA from planktonic and biofilm cells cultured at 25°C for 36 h were sequenced by studying their biological characteristics. The results showed that there were significant differences in the expression levels of 956 genes in biofilms compared with planktonic cells. These differences suggested that two-component regulatory system (TCS) and quorum sensing (QS) regulated V. parahaemolyticus biofilm formation by affecting important factors such as flagellar motility, Extracellular polymeric substance (EPS) secretion, tripartite ATP-independent (TRAP) transport system and ATP binding cassette (ABC) transport system. The present work in transcriptomics serves as a basis for future studies examining the complex network systems that regulate bacterial biofilm formation.
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Affiliation(s)
- Qiuyu Wang
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Pengfei Wang
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Pingping Liu
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Jie Ou
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture and Rural Affairs, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing and Preservation, Shanghai, China
- *Correspondence: Jie Ou,
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14
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Prew MS, Camara CM, Botzanowski T, Moroco JA, Bloch NB, Levy HR, Seo HS, Dhe-Paganon S, Bird GH, Herce HD, Gygi MA, Escudero S, Wales TE, Engen JR, Walensky LD. Structural basis for defective membrane targeting of mutant enzyme in human VLCAD deficiency. Nat Commun 2022; 13:3669. [PMID: 35760926 PMCID: PMC9237092 DOI: 10.1038/s41467-022-31466-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 06/17/2022] [Indexed: 12/03/2022] Open
Abstract
Very long-chain acyl-CoA dehydrogenase (VLCAD) is an inner mitochondrial membrane enzyme that catalyzes the first and rate-limiting step of long-chain fatty acid oxidation. Point mutations in human VLCAD can produce an inborn error of metabolism called VLCAD deficiency that can lead to severe pathophysiologic consequences, including cardiomyopathy, hypoglycemia, and rhabdomyolysis. Discrete mutations in a structurally-uncharacterized C-terminal domain region of VLCAD cause enzymatic deficiency by an incompletely defined mechanism. Here, we conducted a structure-function study, incorporating X-ray crystallography, hydrogen-deuterium exchange mass spectrometry, computational modeling, and biochemical analyses, to characterize a specific membrane interaction defect of full-length, human VLCAD bearing the clinically-observed mutations, A450P or L462P. By disrupting a predicted α-helical hairpin, these mutations either partially or completely impair direct interaction with the membrane itself. Thus, our data support a structural basis for VLCAD deficiency in patients with discrete mutations in an α-helical membrane-binding motif, resulting in pathologic enzyme mislocalization.
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Affiliation(s)
- Michelle S. Prew
- grid.65499.370000 0001 2106 9910Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Christina M. Camara
- grid.65499.370000 0001 2106 9910Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Thomas Botzanowski
- grid.261112.70000 0001 2173 3359Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA USA
| | - Jamie A. Moroco
- grid.261112.70000 0001 2173 3359Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA USA
| | - Noah B. Bloch
- grid.65499.370000 0001 2106 9910Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Hannah R. Levy
- grid.65499.370000 0001 2106 9910Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Hyuk-Soo Seo
- grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Sirano Dhe-Paganon
- grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Gregory H. Bird
- grid.65499.370000 0001 2106 9910Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Henry D. Herce
- grid.65499.370000 0001 2106 9910Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Micah A. Gygi
- grid.65499.370000 0001 2106 9910Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Silvia Escudero
- grid.65499.370000 0001 2106 9910Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA
| | - Thomas E. Wales
- grid.261112.70000 0001 2173 3359Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA USA
| | - John R. Engen
- grid.261112.70000 0001 2173 3359Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA USA
| | - Loren D. Walensky
- grid.65499.370000 0001 2106 9910Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.65499.370000 0001 2106 9910Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA USA
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15
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CRISPR Interference (CRISPRi) Mediated Suppression of OmpR Gene in E. coli: An Alternative Approach to Inhibit Biofilm. Curr Microbiol 2022; 79:78. [DOI: 10.1007/s00284-021-02760-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 12/30/2021] [Indexed: 11/03/2022]
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16
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Tagua VG, Molina‐Henares MA, Travieso ML, Nisa‐Martínez R, Quesada JM, Espinosa‐Urgel M, Ramos‐González MI. C‐di‐GMP
and biofilm are regulated in
Pseudomonas putida
by the
CfcA
/
CfcR
two‐component system in response to salts. Environ Microbiol 2022; 24:158-178. [DOI: 10.1111/1462-2920.15891] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 12/14/2021] [Accepted: 12/26/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Víctor G. Tagua
- Department of Environmental Protection Estación Experimental del Zaidín, CSIC Granada Spain
| | | | - María L. Travieso
- Department of Environmental Protection Estación Experimental del Zaidín, CSIC Granada Spain
| | - Rafael Nisa‐Martínez
- Department of Environmental Protection Estación Experimental del Zaidín, CSIC Granada Spain
| | - José Miguel Quesada
- Department of Environmental Protection Estación Experimental del Zaidín, CSIC Granada Spain
| | - Manuel Espinosa‐Urgel
- Department of Environmental Protection Estación Experimental del Zaidín, CSIC Granada Spain
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17
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Diversity in Sensing and Signaling of Bacterial Sensor Histidine Kinases. Biomolecules 2021; 11:biom11101524. [PMID: 34680156 PMCID: PMC8534201 DOI: 10.3390/biom11101524] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/13/2021] [Accepted: 10/13/2021] [Indexed: 11/17/2022] Open
Abstract
Two-component signal transduction systems (TCSs) are widely conserved in bacteria to respond to and adapt to the changing environment. Since TCSs are also involved in controlling the expression of virulence, biofilm formation, quorum sensing, and antimicrobial resistance in pathogens, they serve as candidates for novel drug targets. TCSs consist of a sensor histidine kinase (HK) and its cognate response regulator (RR). Upon perception of a signal, HKs autophosphorylate their conserved histidine residues, followed by phosphotransfer to their partner RRs. The phosphorylated RRs mostly function as transcriptional regulators and control the expression of genes necessary for stress response. HKs sense their specific signals not only in their extracytoplasmic sensor domain but also in their cytoplasmic and transmembrane domains. The signals are sensed either directly or indirectly via cofactors and accessory proteins. Accumulating evidence shows that a single HK can sense and respond to multiple signals in different domains. The underlying molecular mechanisms of how HK activity is controlled by these signals have been extensively studied both biochemically and structurally. In this article, we introduce the wide diversity of signal perception in different domains of HKs, together with their recently clarified structures and molecular mechanisms.
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18
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Akella R, Humphreys JM, Sekulski K, He H, Durbacz M, Chakravarthy S, Liwocha J, Mohammed ZJ, Brautigam CA, Goldsmith EJ. Osmosensing by WNK Kinases. Mol Biol Cell 2021; 32:1614-1623. [PMID: 33689398 PMCID: PMC8684725 DOI: 10.1091/mbc.e20-01-0089] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/11/2021] [Accepted: 02/22/2021] [Indexed: 12/13/2022] Open
Abstract
With No Lysine (K) WNK kinases regulate electro-neutral cotransporters that are controlled by osmotic stress and chloride. We showed previously that autophosphorylation of WNK1 is inhibited by chloride, raising the possibility that WNKs are activated by osmotic stress. Here we demonstrate that unphosphorylated WNK isoforms 3 and 1 autophosphorylate in response to osmotic pressure in vitro, applied with the crowding agent polyethylene glycol (PEG)400 or osmolyte ethylene glycol (EG), and that this activation is opposed by chloride. Small angle x-ray scattering of WNK3 in the presence and absence of PEG400, static light scattering in EG, and crystallography of WNK1 were used to understand the mechanism. Osmosensing in WNK3 and WNK1 appears to occur through a conformational equilibrium between an inactive, unphosphorylated, chloride-binding dimer and an autophosphorylation-competent monomer. An improved structure of the inactive kinase domain of WNK1, and a comparison with the structure of a monophosphorylated form of WNK1, suggests that large cavities, greater hydration, and specific bound water may participate in the osmosensing mechanism. Our prior work showed that osmolytes have effects on the structure of phosphorylated WNK1, suggestive of multiple stages of osmotic regulation in WNKs.
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Affiliation(s)
- Radha Akella
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - John M. Humphreys
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Kamil Sekulski
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Haixia He
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Mateusz Durbacz
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Srinivas Chakravarthy
- Department of Biology, Chemistry, & Physical Sciences, APS/Illinois Institute of Technology, Argonne, IL 60439
| | - Joanna Liwocha
- Department of Molecular Biology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | | | - Chad A. Brautigam
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Microbiology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Elizabeth J. Goldsmith
- Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, TX 75390
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19
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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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20
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Kenney LJ. How Can a Histidine Kinase Respond to Mechanical Stress? Front Microbiol 2021; 12:655942. [PMID: 34335491 PMCID: PMC8320348 DOI: 10.3389/fmicb.2021.655942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 06/08/2021] [Indexed: 11/30/2022] Open
Abstract
Bacteria respond to physical forces perceived as mechanical stress as part of their comprehensive environmental sensing strategy. Histidine kinases can then funnel diverse environmental stimuli into changes in gene expression through a series of phosphorelay reactions. Because histidine kinases are most often embedded in the inner membrane, they can be sensitive to changes in membrane tension that occurs, for example, in response to osmotic stress, or when deformation of the cell body occurs upon encountering a surface before forming biofilms, or inside the host in response to shear stress in the kidney, intestine, lungs, or blood stream. A summary of our recent work that links the histidine kinase EnvZ to mechanical changes in the inner membrane is provided and placed in a context of other bacterial systems that respond to mechanical stress.
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Affiliation(s)
- Linda J Kenney
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States
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21
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Ko D, Choi SH. Comparative genomics reveals an SNP potentially leading to phenotypic diversity of Salmonella enterica serovar Enteritidis. Microb Genom 2021; 7:000572. [PMID: 33952386 PMCID: PMC8209725 DOI: 10.1099/mgen.0.000572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/29/2021] [Indexed: 12/25/2022] Open
Abstract
An SNP is a spontaneous genetic change having a potential to modify the functions of the original genes and to lead to phenotypic diversity of bacteria in nature. In this study, a phylogenetic analysis of Salmonella enterica serovar Enteritidis, a major food-borne pathogen, showed that eight strains of S. Enteritidis isolated in South Korea, including FORC_075 and FORC_078, have almost identical genome sequences. Interestingly, however, the abilities of FORC_075 to form biofilms and red, dry and rough (RDAR) colonies were significantly impaired, resulting in phenotypic differences among the eight strains. Comparative genomic analyses revealed that one of the non-synonymous SNPs unique to FORC_075 has occurred in envZ, which encodes a sensor kinase of the EnvZ/OmpR two-component system. The SNP in envZ leads to an amino acid change from Pro248 (CCG) in other strains including FORC_078 to Leu248 (CTG) in FORC_075. Allelic exchange of envZ between FORC_075 and FORC_078 identified that the SNP in envZ is responsible for the impaired biofilm- and RDAR colony-forming abilities of S. Enteritidis. Biochemical analyses demonstrated that the SNP in envZ significantly increases the phosphorylated status of OmpR in S. Enteritidis and alters the expression of the OmpR regulon. Phenotypic analyses further identified that the SNP in envZ decreases motility of S. Enteritidis but increases its adhesion and invasion to both human epithelial cells and murine macrophage cells. In addition to an enhancement of infectivity to the host cells, survival under acid stress was also elevated by the SNP in envZ. Together, these results suggest that the natural occurrence of the SNP in envZ could contribute to phenotypic diversity of S. Enteritidis, possibly improving its fitness and pathogenesis.
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Affiliation(s)
- Duhyun Ko
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology and Center for Food and Bioconvergence, Seoul National University, Seoul, Republic of Korea
| | - Sang Ho Choi
- National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology and Center for Food and Bioconvergence, Seoul National University, Seoul, Republic of Korea
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22
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Machas M, Kurgan G, Abed OA, Shapiro A, Wang X, Nielsen D. Characterizing Escherichia coli's transcriptional response to different styrene exposure modes reveals novel toxicity and tolerance insights. J Ind Microbiol Biotechnol 2021; 48:kuab019. [PMID: 33640981 PMCID: PMC9138201 DOI: 10.1093/jimb/kuab019] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/18/2021] [Indexed: 11/24/2022]
Abstract
The global transcriptional response of Escherichia coli to styrene and potential influence of exposure source was determined by performing RNA sequencing (RNA-seq) analysis on both styrene-producing and styrene-exposed cells. In both cases, styrene exposure appears to cause both cell envelope and DNA damage, to which cells respond by down-regulating key genes/pathways involved in DNA replication, protein production, and cell wall biogenesis. Among the most significantly up-regulated genes were those involved with phage shock protein response (e.g. pspABCDE/G), general stress regulators (e.g. marA, rpoH), and membrane-altering genes (notably, bhsA, ompR, ldtC), whereas efflux transporters were, surprisingly, unaffected. Subsequent studies with styrene addition demonstrate how strains lacking ompR [involved in controlling outer membrane (OM) composition/osmoregulation] or any of tolQ, tolA, or tolR (involved in OM constriction) each displayed over 40% reduced growth relative to wild-type. Conversely, despite reducing basal fitness, overexpression of plsX (involved in phospholipid biosynthesis) led to 70% greater growth when styrene exposed. These collective differences point to the likely importance of OM properties in controlling native styrene tolerance. Overall, the collective behaviours suggest that, regardless of source, prolonged exposure to inhibitory styrene levels causes cells to shift from'growth mode' to 'survival mode', redistributing cellular resources to fuel native tolerance mechanisms.
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Affiliation(s)
- Michael Machas
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287-6106, USA
| | - Gavin Kurgan
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-6106, USA
| | - Omar A Abed
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287-6106, USA
| | - Alyssa Shapiro
- Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xuan Wang
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-6106, USA
| | - David Nielsen
- Chemical Engineering, School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, AZ 85287-6106, USA
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23
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Fibriansah G, Lim EXY, Marzinek JK, Ng TS, Tan JL, Huber RG, Lim XN, Chew VSY, Kostyuchenko VA, Shi J, Anand GS, Bond PJ, Crowe JE, Lok SM. Antibody affinity versus dengue morphology influences neutralization. PLoS Pathog 2021; 17:e1009331. [PMID: 33621239 PMCID: PMC7935256 DOI: 10.1371/journal.ppat.1009331] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/05/2021] [Accepted: 01/25/2021] [Indexed: 12/23/2022] Open
Abstract
Different strains within a dengue serotype (DENV1-4) can have smooth, or “bumpy” surface morphologies with different antigenic characteristics at average body temperature (37°C). We determined the neutralizing properties of a serotype cross-reactive human monoclonal antibody (HMAb) 1C19 for strains with differing morphologies within the DENV1 and DENV2 serotypes. We mapped the 1C19 epitope to E protein domain II by hydrogen deuterium exchange mass spectrometry, cryoEM and molecular dynamics simulations, revealing that this epitope is likely partially hidden on the virus surface. We showed the antibody has high affinity for binding to recombinant DENV1 E proteins compared to those of DENV2, consistent with its strong neutralizing activities for all DENV1 strains tested regardless of their morphologies. This finding suggests that the antibody could out-compete E-to-E interaction for binding to its epitope. In contrast, for DENV2, HMAb 1C19 can only neutralize when the epitope becomes exposed on the bumpy-surfaced particle. Although HMAb 1C19 is not a suitable therapeutic candidate, this study with HMAb 1C19 shows the importance of choosing a high-affinity antibody that could neutralize diverse dengue virus morphologies for therapeutic purposes. Dengue virus consists of four serotypes (DENV1-4) and there are different strains within a serotype. DENV can have smooth or bumpy surface morphologies at physiological body temperature of 37°C, depending on the strain. We have determined the cryoEM structures of a cross-reactive neutralizing human monoclonal antibody (HMAb) 1C19 in complex with strains of DENV1 and DENV2 that form either smooth or bumpy surface morphologies. We have mapped the epitope of HMAb 1C19 to E protein domain II and the epitope is likely partially hidden on the virus surface. We showed that the antibody has high affinity for binding to recombinant DENV1 E protein than to DENV2 E protein. This explains the strong neutralization activity for all DENV1 strains tested regardless of their morphologies at physiological temperature, whereas it can only neutralize DENV2 strain that exposes the epitope on the bumpy surface particles. These results suggest that high-affinity therapeutic antibodies could neutralize diverse dengue virus morphologies.
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Affiliation(s)
- Guntur Fibriansah
- Emerging Infectious Diseases, Duke–National University of Singapore Medical School, Singapore, Singapore
- Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Elisa X. Y. Lim
- Emerging Infectious Diseases, Duke–National University of Singapore Medical School, Singapore, Singapore
- Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Jan K. Marzinek
- Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore
| | - Thiam-Seng Ng
- Emerging Infectious Diseases, Duke–National University of Singapore Medical School, Singapore, Singapore
- Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Joanne L. Tan
- Emerging Infectious Diseases, Duke–National University of Singapore Medical School, Singapore, Singapore
- Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Roland G. Huber
- Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore
| | - Xin-Ni Lim
- Emerging Infectious Diseases, Duke–National University of Singapore Medical School, Singapore, Singapore
- Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Valerie S. Y. Chew
- Emerging Infectious Diseases, Duke–National University of Singapore Medical School, Singapore, Singapore
- Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Victor A. Kostyuchenko
- Emerging Infectious Diseases, Duke–National University of Singapore Medical School, Singapore, Singapore
- Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Jian Shi
- Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Ganesh S. Anand
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Peter J. Bond
- Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - James E. Crowe
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Departments of Pediatrics and Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- * E-mail: (JEC); (SML)
| | - Shee-Mei Lok
- Emerging Infectious Diseases, Duke–National University of Singapore Medical School, Singapore, Singapore
- Centre for BioImaging Sciences, National University of Singapore, Singapore, Singapore
- * E-mail: (JEC); (SML)
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Baumschlager A, Khammash M. Synthetic Biological Approaches for Optogenetics and Tools for Transcriptional Light-Control in Bacteria. Adv Biol (Weinh) 2021; 5:e2000256. [PMID: 34028214 DOI: 10.1002/adbi.202000256] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 01/11/2021] [Indexed: 12/22/2022]
Abstract
Light has become established as a tool not only to visualize and investigate but also to steer biological systems. This review starts by discussing the unique features that make light such an effective control input in biology. It then gives an overview of how light-control came to progress, starting with photoactivatable compounds and leading up to current genetic implementations using optogenetic approaches. The review then zooms in on optogenetics, focusing on photosensitive proteins, which form the basis for optogenetic engineering using synthetic biological approaches. As the regulation of transcription provides a highly versatile means for steering diverse biological functions, the focus of this review then shifts to transcriptional light regulators, which are presented in the biotechnologically highly relevant model organism Escherichia coli.
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Affiliation(s)
- Armin Baumschlager
- Department of Biosystems Science and Engineering (D-BSSE), ETH-Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Mustafa Khammash
- Department of Biosystems Science and Engineering (D-BSSE), ETH-Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
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25
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Structural basis for promoter DNA recognition by the response regulator OmpR. J Struct Biol 2020; 213:107638. [PMID: 33152421 DOI: 10.1016/j.jsb.2020.107638] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 09/29/2020] [Accepted: 10/04/2020] [Indexed: 11/21/2022]
Abstract
OmpR, a response regulator of the EnvZ/OmpR two-component system (TCS), controls the reciprocal regulation of two porin proteins, OmpF and OmpC, in bacteria. During signal transduction, OmpR (OmpR-FL) undergoes phosphorylation at its conserved Asp residue in the N-terminal receiver domain (OmpRn) and recognizes the promoter DNA from its C-terminal DNA-binding domain (OmpRc) to elicit an adaptive response. Apart from that, OmpR regulates many genes in Escherichia coli and is important for virulence in several pathogens. However, the molecular mechanism of the regulation and the structural basis of OmpR-DNA binding is still not fully clear. In this study, we presented the crystal structure of OmpRc in complex with the F1 region of the ompF promoter DNA from E. coli. Our structural analysis suggested that OmpRc binds to its cognate DNA as a homodimer, only in a head-to-tail orientation. Also, the OmpRc apo-form showed a unique domain-swapped crystal structure under different crystallization conditions. Biophysical experimental data, such as NMR, fluorescent polarization and thermal stability, showed that inactive OmpR-FL (unphosphorylated) could bind to promoter DNA with a weaker binding affinity as compared with active OmpR-FL (phosphorylated) or OmpRc, and also confirmed that phosphorylation may only enhance DNA binding. Furthermore, the dimerization interfaces in the OmpRc-DNA complex structure identified in this study provide an opportunity to understand the regulatory role of OmpR and explore the potential for this "druggable" target.
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26
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Akella R, Drozdz MA, Humphreys JM, Jiou J, Durbacz MZ, Mohammed ZJ, He H, Liwocha J, Sekulski K, Goldsmith EJ. A Phosphorylated Intermediate in the Activation of WNK Kinases. Biochemistry 2020; 59:1747-1755. [PMID: 32314908 PMCID: PMC7914002 DOI: 10.1021/acs.biochem.0c00146] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
WNK kinases autoactivate by autophosphorylation. Crystallography of the kinase domain of WNK1 phosphorylated on the primary activating site (pWNK1) in the presence of AMP-PNP reveals a well-ordered but inactive configuration. This new pWNK1 structure features specific and unique interactions of the phosphoserine, less hydration, and smaller cavities compared with those of unphosphorylated WNK1 (uWNK1). Because WNKs are activated by osmotic stress in cells, we addressed whether the structure was influenced directly by osmotic pressure. pWNK1 crystals formed in PEG3350 were soaked in the osmolyte sucrose. Suc-WNK1 crystals maintained X-ray diffraction, but the lattice constants and pWNK1 structure changed. Differences were found in the activation loop and helix C, common switch loci in kinase activation. On the basis of these structural changes, we tested for effects on in vitro activity of two WNKs, pWNK1 and pWNK3. The osmolyte PEG400 enhanced ATPase activity. Our data suggest multistage activation of WNKs.
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Affiliation(s)
- Radha Akella
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8816, USA
| | - Mateusz A. Drozdz
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8816, USA
| | - John M. Humphreys
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8816, USA
| | - Jenny Jiou
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8816, USA
| | - Mateusz Z. Durbacz
- Faculty of Agronomy and Bioengineering, University of Life Sciences, Wojska Polskiego 28, 60-624 Poznan, Poland
| | - Zuhair J. Mohammed
- Biomedical Engineering, University of Texas at Dallas, Richardson, TX 75080
| | - Haixia He
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8816, USA
| | - Joanna Liwocha
- Department of Molecular Machines and Signaling, Max Planck Institute for Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Kamil Sekulski
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8816, USA
| | - Elizabeth J. Goldsmith
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8816, USA
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Metagenomic insights into the changes in microbial community and antimicrobial resistance genes associated with different salt content of red pepper (Capsicum annuum L.) sauce. Food Microbiol 2020; 85:103295. [DOI: 10.1016/j.fm.2019.103295] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/03/2019] [Accepted: 08/07/2019] [Indexed: 01/06/2023]
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28
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Kenney LJ, Anand GS. EnvZ/OmpR Two-Component Signaling: An Archetype System That Can Function Noncanonically. EcoSal Plus 2020; 9:10.1128/ecosalplus.ESP-0001-2019. [PMID: 32003321 PMCID: PMC7192543 DOI: 10.1128/ecosalplus.esp-0001-2019] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Indexed: 01/09/2023]
Abstract
Two-component regulatory systems represent the major paradigm for signal transduction in prokaryotes. The simplest systems are composed of a sensor kinase and a response regulator. The sensor is often a membrane protein that senses a change in environmental conditions and is autophosphorylated by ATP on a histidine residue. The phosphoryl group is transferred onto an aspartate of the response regulator, which activates the regulator and alters its output, usually resulting in a change in gene expression. In this review, we present a historical view of the archetype EnvZ/OmpR two-component signaling system, and then we provide a new view of signaling based on our recent experiments. EnvZ responds to cytoplasmic signals that arise from changes in the extracellular milieu, and OmpR acts canonically (requiring phosphorylation) to regulate the porin genes and noncanonically (without phosphorylation) to activate the acid stress response. Herein, we describe how insights gleaned from stimulus recognition and response in EnvZ are relevant to nearly all sensor kinases and response regulators.
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Affiliation(s)
- Linda J Kenney
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555
- Mechanobiology Institute, T-Lab, National University of Singapore, Singapore
| | - Ganesh S Anand
- Department of Biological Sciences, National University of Singapore, Singapore
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Trajtenberg F, Buschiazzo A. Protein Dynamics in Phosphoryl-Transfer Signaling Mediated by Two-Component Systems. Methods Mol Biol 2020; 2077:1-18. [PMID: 31707648 DOI: 10.1007/978-1-4939-9884-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The ability to perceive the environment, an essential attribute in living organisms, is linked to the evolution of signaling proteins that recognize specific signals and execute predetermined responses. Such proteins constitute concerted systems that can be as simple as a unique protein, able to recognize a ligand and exert a phenotypic change, or extremely complex pathways engaging dozens of different proteins which act in coordination with feedback loops and signal modulation. To understand how cells sense their surroundings and mount specific adaptive responses, we need to decipher the molecular workings of signal recognition, internalization, transfer, and conversion into chemical changes inside the cell. Protein allostery and dynamics play a central role. Here, we review recent progress on the study of two-component systems, important signaling machineries of prokaryotes and lower eukaryotes. Such systems implicate a sensory histidine kinase and a separate response regulator protein. Both components exploit protein flexibility to effect specific conformational rearrangements, modulating protein-protein interactions, and ultimately transmitting information accurately. Recent work has revealed how histidine kinases switch between discrete functional states according to the presence or absence of the signal, shifting key amino acid positions that define their catalytic activity. In concert with the cognate response regulator's allosteric changes, the phosphoryl-transfer flow during the signaling process is exquisitely fine-tuned for proper specificity, efficiency and directionality.
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Affiliation(s)
- Felipe Trajtenberg
- Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Alejandro Buschiazzo
- Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay.
- Département de Microbiologie, Institut Pasteur, Paris, France.
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30
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Desai SK, Kenney LJ. Switching Lifestyles Is an in vivo Adaptive Strategy of Bacterial Pathogens. Front Cell Infect Microbiol 2019; 9:421. [PMID: 31921700 PMCID: PMC6917575 DOI: 10.3389/fcimb.2019.00421] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/28/2019] [Indexed: 01/05/2023] Open
Abstract
Gram-positive and Gram-negative pathogens exist as planktonic cells only at limited times during their life cycle. In response to environmental signals such as temperature, pH, osmolality, and nutrient availability, pathogenic bacteria can adopt varied cellular fates, which involves the activation of virulence gene programs and/or the induction of a sessile lifestyle to form multicellular surface-attached communities. In Salmonella, SsrB is the response regulator which governs the lifestyle switch from an intracellular virulent state to form dormant biofilms in chronically infected hosts. Using the Salmonella lifestyle switch as a paradigm, we herein compare how other pathogens alter their lifestyles to enable survival, colonization and persistence in response to different environmental cues. It is evident that lifestyle switching often involves transcriptional regulators and their modification as highlighted here. Phenotypic heterogeneity resulting from stochastic cellular processes can also drive lifestyle variation among members of a population, although this subject is not considered in the present review.
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Affiliation(s)
- Stuti K. Desai
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Linda J. Kenney
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States
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31
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Zheng J, Strutzenberg T, Pascal BD, Griffin PR. Protein dynamics and conformational changes explored by hydrogen/deuterium exchange mass spectrometry. Curr Opin Struct Biol 2019; 58:305-313. [DOI: 10.1016/j.sbi.2019.06.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 06/15/2019] [Accepted: 06/25/2019] [Indexed: 12/31/2022]
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32
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Li X, Eyles SJ, Thompson LK. Hydrogen exchange of chemoreceptors in functional complexes suggests protein stabilization mediates long-range allosteric coupling. J Biol Chem 2019; 294:16062-16079. [PMID: 31506298 DOI: 10.1074/jbc.ra119.009865] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/08/2019] [Indexed: 11/06/2022] Open
Abstract
Bacterial chemotaxis receptors form extended hexagonal arrays that integrate and amplify signals to control swimming behavior. Transmembrane signaling begins with a 2-Å ligand-induced displacement of an α helix in the periplasmic and transmembrane domains, but it is unknown how the cytoplasmic domain propagates the signal an additional 200 Å to control the kinase CheA bound to the membrane-distal tip of the receptor. The receptor cytoplasmic domain has previously been shown to be highly dynamic as both a cytoplasmic fragment (CF) and within the intact chemoreceptor; modulation of its dynamics is thought to play a key role in signal propagation. This hydrogen deuterium exchange-MS (HDX-MS) study of functional complexes of CF, CheA, and CheW bound to vesicles in native-like arrays reveals that the CF is well-ordered only in its protein interaction region where it binds CheA and CheW. We observe rapid exchange throughout the rest of the CF, with both uncorrelated (EX2) and correlated (EX1) exchange patterns, suggesting the receptor cytoplasmic domain retains disorder even within functional complexes. HDX rates are increased by inputs that favor the kinase-off state. We propose that chemoreceptors achieve long-range allosteric control of the kinase through a coupled equilibrium: CheA binding in a kinase-on conformation stabilizes the cytoplasmic domain, and signaling inputs that destabilize this domain (ligand binding and demethylation) disfavor CheA binding such that it loses key contacts and reverts to a kinase-off state. This study reveals the mechanistic role of an intrinsically disordered region of a transmembrane receptor in long-range allostery.
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Affiliation(s)
- Xuni Li
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Stephen J Eyles
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Lynmarie K Thompson
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003 .,Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003
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33
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Insights into histidine kinase activation mechanisms from the monomeric blue light sensor EL346. Proc Natl Acad Sci U S A 2019; 116:4963-4972. [PMID: 30808807 DOI: 10.1073/pnas.1813586116] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Translation of environmental cues into cellular behavior is a necessary process in all forms of life. In bacteria, this process frequently involves two-component systems in which a sensor histidine kinase (HK) autophosphorylates in response to a stimulus before subsequently transferring the phosphoryl group to a response regulator that controls downstream effectors. Many details of the molecular mechanisms of HK activation are still unclear due to complications associated with the multiple signaling states of these large, multidomain proteins. To address these challenges, we combined complementary solution biophysical approaches to examine the conformational changes upon activation of a minimal, blue-light-sensing histidine kinase from Erythrobacter litoralis HTCC2594, EL346. Our data show that multiple conformations coexist in the dark state of EL346 in solution, which may explain the enzyme's residual dark-state activity. We also observe that activation involves destabilization of the helices in the dimerization and histidine phosphotransfer-like domain, where the phosphoacceptor histidine resides, and their interactions with the catalytic domain. Similar light-induced changes occur to some extent even in constitutively active or inactive mutants, showing that light sensing can be decoupled from activation of kinase activity. These structural changes mirror those inferred by comparing X-ray crystal structures of inactive and active HK fragments, suggesting that they are at the core of conformational changes leading to HK activation. More broadly, our findings uncover surprising complexity in this simple system and allow us to outline a mechanism of the multiple steps of HK activation.
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Ghosh M, Wang LC, Huber RG, Gao Y, Morgan LK, Tulsian NK, Bond PJ, Kenney LJ, Anand GS. Engineering an Osmosensor by Pivotal Histidine Positioning within Disordered Helices. Structure 2019; 27:302-314.e4. [PMID: 30503779 DOI: 10.1016/j.str.2018.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 08/18/2018] [Accepted: 10/18/2018] [Indexed: 10/27/2022]
Abstract
Histidine kinases (HKs) funnel diverse environmental stimuli into a single autophosphorylation event at a conserved histidine residue. The HK EnvZ is a global sensor of osmolality and cellular acid pH. In previous studies, we discovered that osmosensing in EnvZ was mediated through osmolyte-induced stabilization of the partially disordered helical backbone spanning the conserved histidine autophosphorylation site (His243). Here, we describe how backbone stabilization leads to changes in the microenvironment of His243, resulting in enhanced autophosphorylation through relief of inhibition and repositioning of critical side chains and imidazole rotamerization. The conserved His-Asp/Glu dyad within the partially structured helix is equally geared to respond to acid pH, an alternative environmental stimulus in bacteria. This high-resolution "double-clamp" switch model proposes that a His-Asp/Glu dyad functions as an integrative node for regulating autophosphorylation in HKs. Because the His-Asp/Glu dyad is highly conserved in HKs, this study provides a universal model for describing HK function.
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Affiliation(s)
- Madhubrata Ghosh
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, Nanos, Singapore 138669, Singapore
| | - Loo Chien Wang
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Roland G Huber
- Bioinformatics Institute (A(∗)STAR), 30 Biopolis Street, Matrix, Singapore 138671, Singapore
| | - Yunfeng Gao
- Mechanobiology Institute, 5A Engineering Drive 1, Singapore 117411, Singapore
| | - Leslie K Morgan
- Jesse Brown Veteran Affairs Medical Center, 820 S. Damen Avenue, Chicago, IL 60612, USA; Department of Microbiology and Immunology, University of Illinois-Chicago, 835 S. Wolcott Avenue, Chicago, IL 60612, USA
| | - Nikhil Kumar Tulsian
- Department of Biochemistry, National University of Singapore, 28 Medical Drive, Singapore 117546, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Peter J Bond
- Bioinformatics Institute (A(∗)STAR), 30 Biopolis Street, Matrix, Singapore 138671, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Linda J Kenney
- Mechanobiology Institute, 5A Engineering Drive 1, Singapore 117411, Singapore; Jesse Brown Veteran Affairs Medical Center, 820 S. Damen Avenue, Chicago, IL 60612, USA; Department of Microbiology and Immunology, University of Illinois-Chicago, 835 S. Wolcott Avenue, Chicago, IL 60612, USA; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore.
| | - Ganesh S Anand
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore.
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35
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Kenney LJ. The role of acid stress in Salmonella pathogenesis. Curr Opin Microbiol 2019; 47:45-51. [DOI: 10.1016/j.mib.2018.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/10/2018] [Accepted: 11/15/2018] [Indexed: 11/29/2022]
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36
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Mutz YDS, Rosario DKA, Paschoalin VMF, Conte-Junior CA. Salmonella enterica: A hidden risk for dry-cured meat consumption? Crit Rev Food Sci Nutr 2019; 60:976-990. [DOI: 10.1080/10408398.2018.1555132] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Yhan da Silva Mutz
- Chemistry Institute, Federal University of Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, Brazil
- Department of Food Technology, Federal Fluminense University, Vital Brazil Filho, Niterói, RJ, Brazil
| | - Denes Kaic Alves Rosario
- Chemistry Institute, Federal University of Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, Brazil
- Department of Food Technology, Federal Fluminense University, Vital Brazil Filho, Niterói, RJ, Brazil
| | | | - Carlos Adam Conte-Junior
- Chemistry Institute, Federal University of Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, Brazil
- Department of Food Technology, Federal Fluminense University, Vital Brazil Filho, Niterói, RJ, Brazil
- National Institute of Health Quality Control, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
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37
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Exopolysaccharides and Biofilms in Mitigating Salinity Stress: The Biotechnological Potential of Halophilic and Soil-Inhabiting PGPR Microorganisms. SOIL BIOLOGY 2019. [DOI: 10.1007/978-3-030-18975-4_6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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38
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Kielkopf CS, Ghosh M, Anand GS, Brown SHJ. HDX-MS reveals orthosteric and allosteric changes in apolipoprotein-D structural dynamics upon binding of progesterone. Protein Sci 2018; 28:365-374. [PMID: 30353968 DOI: 10.1002/pro.3534] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/11/2018] [Accepted: 10/15/2018] [Indexed: 12/17/2022]
Abstract
Apolipoprotein-D is a glycosylated tetrameric lipocalin that binds and transports small hydrophobic molecules such as progesterone and arachidonic acid. Like other lipocalins, apolipoprotein-D adopts an eight-stranded β-barrel fold stabilized by two intramolecular disulphide bonds, with an adjacent α-helix. Crystallography studies of recombinant apolipoprotein-D demonstrated no major conformational changes upon progesterone binding. Amide hydrogen-deuterium exchange mass spectrometry (HDX-MS) reports structural changes of proteins in solution by monitoring exchange of amide hydrogens in the protein backbone with deuterium. HDX-MS detects changes in conformation and structural dynamics in response to protein function such as ligand binding that may go undetected in X-ray crystallography, making HDX-MS an invaluable orthogonal technique. Here, we report an HDX-MS protocol for apolipoprotein-D that solved challenges of high protein rigidity and low pepsin cleavage using rigorous quenching conditions and longer deuteration times, yielding 85% sequence coverage and 50% deuterium exchange. The relative fractional deuterium exchange of ligand-free apolipoprotein-D revealed apolipoprotein-D to be a highly structured protein. Progesterone binding was detected by significant reduction in deuterium exchange in eight peptides. Stabilization of apolipoprotein-D dynamics can be interpreted as a combined orthosteric effect in the ligand binding pocket and allosteric effect at the N-terminus and C-terminus. Together, our experiments provide insight into apolipoprotein-D structural dynamics and map the effects of progesterone binding that are relayed to distal parts of the protein. The observed stabilization of apolipoprotein-D dynamics upon progesterone binding demonstrates a common behaviour in the lipocalin family and may have implications for interactions of apolipoprotein-D with receptors or lipoprotein particles. Statement: We reveal for the first time how apolipoprotein-D, which is protective in Alzheimer's disease, becomes more ordered when bound to a molecule of steroid hormone. These results significantly extend the understanding of apolipoprotein-D structure from X-ray crystallography studies by incorporating information on how protein motion changes over time. To achieve these results an improved protocol was developed, suitable for proteins similar to apolipoprotein-D, to elucidate how proteins change flexibility when binding to small molecules.
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Affiliation(s)
- Claudia S Kielkopf
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia.,Molecular Horizons, University of Wollongong, Wollongong, New South Wales, Australia.,School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Madhubrata Ghosh
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Ganesh S Anand
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Simon H J Brown
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia.,Molecular Horizons, University of Wollongong, Wollongong, New South Wales, Australia.,School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia
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39
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Ramesh R, Lim XX, Raghuvamsi PV, Wu C, Wong SM, Anand GS. Uncovering metastability and disassembly hotspots in whole viral particles. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 143:5-12. [PMID: 30553754 DOI: 10.1016/j.pbiomolbio.2018.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/26/2018] [Accepted: 12/12/2018] [Indexed: 01/18/2023]
Abstract
Viruses are metastable macromolecular assemblies that toggle between multiple conformational states through molecular rearrangements that are critical for mediating viral host entry. Viruses respond to different host specific environmental cues to form disassembly intermediates for the eventual release of genomic material required for replication. Although static snapshots of these intermediates have been captured through structural techniques such as X-ray crystallography and cryo-EM, the mechanistic details of these conformational rearrangements underpinning viral metastability have been poorly understood. Amide hydrogen deuterium exchange mass spectrometry (HDXMS) is a powerful tool that measures hydrogen bonding propensities to probe changes in the dynamics of different macromolecular interactions. Chaotropic agents such as urea can be used to disrupt hydrogen bonds between different subunits, thereby ranking regions of the virus that are critical in maintaining viral stability. By controlled urea denaturation with HDXMS, we have identified specific loci in a Turnip Crinkle Virus (TCV) model showing increased deuterium exchange with even minimally disruptive concentrations of urea. These loci represent dynamic disassembly hotspots. These hotspots are predominantly present at the quaternary contacts at the 3-fold and 5-fold axes. This approach can be applied to detect vulnerabilities in virus icosahedral structures to uncover the molecular mechanism of viral disassembly.
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Affiliation(s)
- Ranita Ramesh
- Department of Biological Sciences, National University of Singapore, 117543, Singapore
| | - Xin Xiang Lim
- Department of Biological Sciences, National University of Singapore, 117543, Singapore
| | | | - Chao Wu
- Department of Biological Sciences, National University of Singapore, 117543, Singapore
| | - Sek Man Wong
- Department of Biological Sciences, National University of Singapore, 117543, Singapore; Temasek Life Sciences Laboratory, Singapore, 117604, Singapore
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Martín-Mora D, Fernández M, Velando F, Ortega Á, Gavira JA, Matilla MA, Krell T. Functional Annotation of Bacterial Signal Transduction Systems: Progress and Challenges. Int J Mol Sci 2018; 19:ijms19123755. [PMID: 30486299 PMCID: PMC6321045 DOI: 10.3390/ijms19123755] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 01/15/2023] Open
Abstract
Bacteria possess a large number of signal transduction systems that sense and respond to different environmental cues. Most frequently these are transcriptional regulators, two-component systems and chemosensory pathways. A major bottleneck in the field of signal transduction is the lack of information on signal molecules that modulate the activity of the large majority of these systems. We review here the progress made in the functional annotation of sensor proteins using high-throughput ligand screening approaches of purified sensor proteins or individual ligand binding domains. In these assays, the alteration in protein thermal stability following ligand binding is monitored using Differential Scanning Fluorimetry. We illustrate on several examples how the identification of the sensor protein ligand has facilitated the elucidation of the molecular mechanism of the regulatory process. We will also discuss the use of virtual ligand screening approaches to identify sensor protein ligands. Both approaches have been successfully applied to functionally annotate a significant number of bacterial sensor proteins but can also be used to study proteins from other kingdoms. The major challenge consists in the study of sensor proteins that do not recognize signal molecules directly, but that are activated by signal molecule-loaded binding proteins.
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Affiliation(s)
- David Martín-Mora
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
| | - Matilde Fernández
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
| | - Félix Velando
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
| | - Álvaro Ortega
- Department of Biochemistry and Molecular Biology 'B' and Immunology, Faculty of Chemistry, University of Murcia, Campus of Espinardo, Regional Campus of International Excellence "Campus Mare Nostrum", 30100 Murcia, Spain.
| | - José A Gavira
- Laboratorio de Estudios Cristalográficos, IACT, (CSIC-UGR), Avenida las Palmeras 4, 18100 Armilla, Spain.
| | - Miguel A Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain.
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Chakraborty S, Kenney LJ. A New Role of OmpR in Acid and Osmotic Stress in Salmonella and E. coli. Front Microbiol 2018; 9:2656. [PMID: 30524381 PMCID: PMC6262077 DOI: 10.3389/fmicb.2018.02656] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/17/2018] [Indexed: 12/24/2022] Open
Abstract
Bacteria survive and respond to diverse environmental conditions and during infection inside the host by systematic regulation of stress response genes. E. coli and S. Typhimurium can undergo large changes in intracellular osmolality (up to 1.8 Osmol/kg) and can tolerate cytoplasmic acidification to at least pHi 5.6. Recent analyses of single cells challenged a long held view that bacteria respond to extracellular acid stress by rapid acidification followed by a rapid recovery. It is now appreciated that both S. Typhimurium and E. coli maintain an acidic cytoplasm through the actions of the outer membrane protein regulator OmpR via its regulation of distinct signaling pathways. However, a comprehensive comparison of OmpR regulons between S. Typhimurium and E. coli is lacking. In this study, we examined the expression profiles of wild-type and ompR null strains of the intracellular pathogen S. Typhimurium and a commensal E. coli in response to acid and osmotic stress. Herein, we classify distinct OmpR regulons and also identify shared OmpR regulatory pathways between S. Typhimurium and E. coli in response to acid and osmotic stress. Our study establishes OmpR as a key regulator of bacterial virulence, growth and metabolism, in addition to its role in regulating outer membrane proteins.
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Affiliation(s)
- Smarajit Chakraborty
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Linda J. Kenney
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
- Departments of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, United States
- Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
- Jesse Brown Veterans Administration Medical Center, Chicago, IL, United States
- *Correspondence: Linda J. Kenney,
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Bi S, Jin F, Sourjik V. Inverted signaling by bacterial chemotaxis receptors. Nat Commun 2018; 9:2927. [PMID: 30050034 PMCID: PMC6062612 DOI: 10.1038/s41467-018-05335-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/02/2018] [Indexed: 11/09/2022] Open
Abstract
Microorganisms use transmembrane sensory receptors to perceive a wide range of environmental factors. It is unclear how rapidly the sensory properties of these receptors can be modified when microorganisms adapt to novel environments. Here, we demonstrate experimentally that the response of an Escherichia coli chemotaxis receptor to its chemical ligands can be easily inverted by mutations at several sites along receptor sequence. We also perform molecular dynamics simulations to shed light on the mechanism of the transmembrane signaling by E. coli chemoreceptors. Finally, we use receptors with inverted signaling to map determinants that enable the same receptor to sense multiple environmental factors, including metal ions, aromatic compounds, osmotic pressure, and salt ions. Our findings demonstrate high plasticity of signaling and provide further insights into the mechanisms of stimulus sensing and processing by bacterial chemoreceptors. Bacteria use chemotaxis receptors to perceive environmental factors. Here, the authors show that mutations in a chemotaxis receptor can invert the sensory response, e.g. from attractant to repellent, and use these mutants to map regions that enable the receptor to sense multiple environmental factors.
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Affiliation(s)
- Shuangyu Bi
- Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, 35043, Germany
| | - Fan Jin
- Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, 35043, Germany
| | - Victor Sourjik
- Max Planck Institute for Terrestrial Microbiology & LOEWE Center for Synthetic Microbiology (SYNMIKRO), Marburg, 35043, Germany.
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43
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The role of polyproline motifs in the histidine kinase EnvZ. PLoS One 2018; 13:e0199782. [PMID: 29953503 PMCID: PMC6023141 DOI: 10.1371/journal.pone.0199782] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 06/13/2018] [Indexed: 12/20/2022] Open
Abstract
Although distinct amino acid motifs containing consecutive prolines (polyP) cause ribosome stalling, which necessitates recruitment of the translation elongation factor P (EF-P), they occur strikingly often in bacterial proteomes. For example, polyP motifs are found in more than half of all histidine kinases in Escherichia coli K-12, which raises the question of their role(s) in receptor function. Here we have investigated the roles of two polyP motifs in the osmosensor and histidine kinase EnvZ. We show that the IPPPL motif in the HAMP domain is required for dimerization of EnvZ. Moreover, replacement of the prolines in this motif by alanines disables the receptor’s sensor function. The second motif, VVPPA, which is located in the periplasmic domain, was found to be required for interaction with the modulator protein MzrA. Our study also reveals that polyP-dependent stalling has little effect on EnvZ levels. Hence, both polyP motifs in EnvZ are primarily involved in protein-protein interaction. Furthermore, while the first motif occurs in almost all EnvZ homologues, the second motif is only found in species that have MzrA, indicating co-evolution of the two proteins.
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Ibrahim IM, Wang L, Puthiyaveetil S, Krauß N, Nield J, Allen JF. Oligomeric states in sodium ion-dependent regulation of cyanobacterial histidine kinase-2. PROTOPLASMA 2018; 255:937-952. [PMID: 29290041 PMCID: PMC5904244 DOI: 10.1007/s00709-017-1196-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 12/05/2017] [Indexed: 06/07/2023]
Abstract
Two-component signal transduction systems (TCSs) consist of sensor histidine kinases and response regulators. TCSs mediate adaptation to environmental changes in bacteria, plants, fungi and protists. Histidine kinase 2 (Hik2) is a sensor histidine kinase found in all known cyanobacteria and as chloroplast sensor kinase in eukaryotic algae and plants. Sodium ions have been shown to inhibit the autophosphorylation activity of Hik2 that precedes phosphoryl transfer to response regulators, but the mechanism of inhibition has not been determined. We report on the mechanism of Hik2 activation and inactivation probed by chemical cross-linking and size exclusion chromatography together with direct visualisation of the kinase using negative-stain transmission electron microscopy of single particles. We show that the functional form of Hik2 is a higher-order oligomer such as a hexamer or octamer. Increased NaCl concentration converts the active hexamer into an inactive tetramer. The action of NaCl appears to be confined to the Hik2 kinase domain.
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Affiliation(s)
- Iskander M Ibrahim
- Department of Biochemistry and Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Liang Wang
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Sujith Puthiyaveetil
- Department of Biochemistry and Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Norbert Krauß
- Botanisches Institut, Karlsruher Institut für Technologie, Karlsruhe, Germany
| | - Jon Nield
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - John F Allen
- Research Department of Genetics, Evolution and Environment, University College London, London, UK.
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Guo Y, Iavarone AT, Cooper MM, Marletta MA. Mapping the H-NOX/HK Binding Interface in Vibrio cholerae by Hydrogen/Deuterium Exchange Mass Spectrometry. Biochemistry 2018; 57:1779-1789. [PMID: 29457883 DOI: 10.1021/acs.biochem.8b00027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Heme-nitric oxide/oxygen binding (H-NOX) proteins are a group of hemoproteins that bind diatomic gas ligands such as nitric oxide (NO) and oxygen (O2). H-NOX proteins typically regulate histidine kinases (HK) located within the same operon. It has been reported that NO-bound H-NOXs inhibit cognate histidine kinase autophosphorylation in bacterial H-NOX/HK complexes; however, a detailed mechanism of NO-mediated regulation of the H-NOX/HK activity remains unknown. In this study, the binding interface of Vibrio cholerae ( Vc) H-NOX/HK complex was characterized by hydrogen/deuterium exchange mass spectrometry (HDX-MS) and further validated by mutagenesis, leading to a new model for NO-dependent kinase inhibition. A conformational change in Vc H-NOX introduced by NO generates a new kinase-binding interface, thus locking the kinase in an inhibitory conformation.
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46
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Reciprocal Regulation of OmpR and Hfq and Their Regulatory Actions on the Vi Polysaccharide Capsular Antigen in Salmonella enterica Serovar Typhi. Curr Microbiol 2018; 75:773-778. [DOI: 10.1007/s00284-018-1447-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 01/31/2018] [Indexed: 11/30/2022]
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Abstract
The PhoQ/PhoP two-component system plays an essential role in the response of enterobacteria to the environment of their mammalian hosts. It is known to sense several stimuli that are potentially associated with the host, including extracellular magnesium limitation, low pH, and the presence of cationic antimicrobial peptides. Here, we show that the PhoQ/PhoP two-component systems of Escherichia coli and Salmonella can also perceive an osmotic upshift, another key stimulus to which bacteria become exposed within the host. In contrast to most previously established stimuli of PhoQ, the detection of osmotic upshift does not require its periplasmic sensor domain. Instead, we show that the activity of PhoQ is affected by the length of the transmembrane (TM) helix as well as by membrane lateral pressure. We therefore propose that osmosensing relies on a conformational change within the TM domain of PhoQ induced by a perturbation in cell membrane thickness and lateral pressure under hyperosmotic conditions. Furthermore, the response mediated by the PhoQ/PhoP two-component system was found to improve bacterial growth recovery under hyperosmotic stress, partly through stabilization of the sigma factor RpoS. Our findings directly link the PhoQ/PhoP two-component system to bacterial osmosensing, suggesting that this system can mediate a concerted response to most of the established host-related cues.
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Chakraborty S, Winardhi RS, Morgan LK, Yan J, Kenney LJ. Non-canonical activation of OmpR drives acid and osmotic stress responses in single bacterial cells. Nat Commun 2017; 8:1587. [PMID: 29138484 PMCID: PMC5686162 DOI: 10.1038/s41467-017-02030-0] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 11/02/2017] [Indexed: 12/18/2022] Open
Abstract
Unlike eukaryotes, bacteria undergo large changes in osmolality and cytoplasmic pH. It has been described that during acid stress, bacteria internal pH promptly acidifies, followed by recovery. Here, using pH imaging in single living cells, we show that following acid stress, bacteria maintain an acidic cytoplasm and the osmotic stress transcription factor OmpR is required for acidification. The activation of this response is non-canonical, involving a regulatory mechanism requiring the OmpR cognate kinase EnvZ, but not OmpR phosphorylation. Single cell analysis further identifies an intracellular pH threshold ~6.5. Acid stress reduces the internal pH below this threshold, increasing OmpR dimerization and DNA binding. During osmotic stress, the internal pH is above the threshold, triggering distinct OmpR-related pathways. Preventing intracellular acidification of Salmonella renders it avirulent, suggesting that acid stress pathways represent a potential therapeutic target. These results further emphasize the advantages of single cell analysis over studies of population averages.
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Affiliation(s)
- Smarajit Chakraborty
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Ricksen S Winardhi
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Department of Physics, National University of Singapore, Singapore, 117551, Singapore
| | - Leslie K Morgan
- Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA.,Department of Microbiology & Immunology, University of Illinois-Chicago, Chicago, IL, 60612, USA
| | - Jie Yan
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Department of Physics, National University of Singapore, Singapore, 117551, Singapore
| | - Linda J Kenney
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, Singapore, 117411, Singapore. .,Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA. .,Department of Microbiology & Immunology, University of Illinois-Chicago, Chicago, IL, 60612, USA. .,Department of Biochemistry, National University of Singapore, Singapore, 117596, Singapore.
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Cai Y, Su M, Ahmad A, Hu X, Sang J, Kong L, Chen X, Wang C, Shuai J, Han A. Conformational dynamics of the essential sensor histidine kinase WalK. Acta Crystallogr D Struct Biol 2017; 73:793-803. [PMID: 28994408 PMCID: PMC5633905 DOI: 10.1107/s2059798317013043] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/12/2017] [Indexed: 12/26/2022] Open
Abstract
Two-component systems (TCSs) are key elements in bacterial signal transduction in response to environmental stresses. TCSs generally consist of sensor histidine kinases (SKs) and their cognate response regulators (RRs). Many SKs exhibit autokinase, phosphoryltransferase and phosphatase activities, which regulate RR activity through a phosphorylation and dephosphorylation cycle. However, how SKs perform different enzymatic activities is poorly understood. Here, several crystal structures of the minimal catalytic region of WalK, an essential SK from Lactobacillus plantarum that shares 60% sequence identity with its homologue VicK from Streptococcus mutans, are presented. WalK adopts an asymmetrical closed structure in the presence of ATP or ADP, in which one of the CA domains is positioned close to the DHp domain, thus leading both the β- and γ-phosphates of ATP/ADP to form hydrogen bonds to the ℇ- but not the δ-nitrogen of the phosphorylatable histidine in the DHp domain. In addition, the DHp domain in the ATP/ADP-bound state has a 25.7° asymmetrical helical bending coordinated with the repositioning of the CA domain; these processes are mutually exclusive and alternate in response to helicity changes that are possibly regulated by upstream signals. In the absence of ATP or ADP, however, WalK adopts a completely symmetric open structure with its DHp domain centred between two outward-reaching CA domains. In summary, these structures of WalK reveal the intrinsic dynamic properties of an SK structure as a molecular basis for multifunctionality.
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Affiliation(s)
- Yongfei Cai
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
| | - Mingyang Su
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
| | - Ashfaq Ahmad
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
| | - Xiaojie Hu
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
| | - Jiayan Sang
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
| | - Lingyuan Kong
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
| | - Xingqiang Chen
- Department of Physics, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
| | - Chen Wang
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
| | - Jianwei Shuai
- Department of Physics, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
| | - Aidong Han
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang’an, Xiamen 361102, People’s Republic of China
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Linearmycins Activate a Two-Component Signaling System Involved in Bacterial Competition and Biofilm Morphology. J Bacteriol 2017; 199:JB.00186-17. [PMID: 28461449 DOI: 10.1128/jb.00186-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/24/2017] [Indexed: 11/20/2022] Open
Abstract
Bacteria use two-component signaling systems to adapt and respond to their competitors and changing environments. For instance, competitor bacteria may produce antibiotics and other bioactive metabolites and sequester nutrients. To survive, some species of bacteria escape competition through antibiotic production, biofilm formation, or motility. Specialized metabolite production and biofilm formation are relatively well understood for bacterial species in isolation. How bacteria control these functions when competitors are present is not well studied. To address fundamental questions relating to the competitive mechanisms of different species, we have developed a model system using two species of soil bacteria, Bacillus subtilis and Streptomyces sp. strain Mg1. Using this model, we previously found that linearmycins produced by Streptomyces sp. strain Mg1 cause lysis of B. subtilis cells and degradation of colony matrix. We identified strains of B. subtilis with mutations in the two-component signaling system yfiJK operon that confer dual phenotypes of specific linearmycin resistance and biofilm morphology. We determined that expression of the ATP-binding cassette (ABC) transporter yfiLMN operon, particularly yfiM and yfiN, is necessary for biofilm morphology. Using transposon mutagenesis, we identified genes that are required for YfiLMN-mediated biofilm morphology, including several chaperones. Using transcriptional fusions, we found that YfiJ signaling is activated by linearmycins and other polyene metabolites. Finally, using a truncated YfiJ, we show that YfiJ requires its transmembrane domain to activate downstream signaling. Taken together, these results suggest coordinated dual antibiotic resistance and biofilm morphology by a single multifunctional ABC transporter promotes competitive fitness of B. subtilisIMPORTANCE DNA sequencing approaches have revealed hitherto unexplored diversity of bacterial species in a wide variety of environments that includes the gastrointestinal tract of animals and the rhizosphere of plants. Interactions between different species in bacterial communities have impacts on our health and industry. However, many approaches currently used to study whole bacterial communities do not resolve mechanistic details of interspecies interactions, including how bacteria sense and respond to their competitors. Using a competition model, we have uncovered dual functions for a previously uncharacterized two-component signaling system involved in specific antibiotic resistance and biofilm morphology. Insights gleaned from signaling within interspecies interaction models build a more complete understanding of gene functions important for bacterial communities and will enhance community-level analytical approaches.
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