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Gao R, Wu T, Stock AM. A conserved inhibitory interdomain interaction regulates DNA-binding activities of hybrid two-component systems in Bacteroides. mBio 2024:e0122024. [PMID: 38842315 DOI: 10.1128/mbio.01220-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 05/02/2024] [Indexed: 06/07/2024] Open
Abstract
Hybrid two-component systems (HTCSs) comprise a major class of transcription regulators of polysaccharide utilization genes in Bacteroides. Distinct from classical two-component systems in which signal transduction is carried out by intermolecular phosphotransfer between a histidine kinase (HK) and a cognate response regulator (RR), HTCSs contain the membrane sensor HK and the RR transcriptional regulator within a single polypeptide chain. Tethering the DNA-binding domain (DBD) of the RR with the dimeric HK domain in an HTCS could potentially promote dimerization of the DBDs and would thus require a mechanism to suppress DNA-binding activity in the absence of stimulus. Analysis of phosphorylation and DNA-binding activities of several HTCSs from Bacteroides thetaiotaomicron revealed a DBD suppression mechanism in which an inhibitory interaction between the DBD and the phosphoryl group-accepting receiver domain (REC) decreases autophosphorylation rates of HTCS-RECs and represses DNA-binding activities in the absence of phosphorylation. Sequence analyses and structure predictions identified a highly conserved sequence motif correlated with a conserved inhibitory domain arrangement of REC and DBD. The presence of the motif, as in most HTCSs, or its absence, in a small subset of HTCSs, is likely predictive of two distinct regulatory mechanisms evolved for different glycans. Substitutions within the conserved motif relieve the inhibitory interaction and result in elevated DNA-binding activities in the absence of phosphorylation. Our data suggest a fundamental regulatory mechanism shared by most HTCSs to suppress DBD activities using a conserved inhibitory interdomain arrangement to overcome the challenge of the fused HK and RR components. IMPORTANCE Different dietary and host-derived complex carbohydrates shape the gut microbial community and impact human health. In Bacteroides, the prevalent gut bacteria genus, utilization of these diverse carbohydrates relies on different gene clusters that are under sophisticated control by various signaling systems, including the hybrid two-component systems (HTCSs). We have uncovered a highly conserved regulatory mechanism in which the output DNA-binding activity of HTCSs is suppressed by interdomain interactions in the absence of stimulating phosphorylation. A consensus amino acid motif is found to correlate with the inhibitory interaction surface while deviations from the consensus can lead to constitutive activation. Understanding of such conserved HTCS features will be important to make regulatory predictions for individual systems as well as to engineer novel systems with substitutions in the consensus to explore the glycan regulation landscape in Bacteroides.
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Affiliation(s)
- Rong Gao
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Ti Wu
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Ann M Stock
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
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2
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Azorhizobium caulinodans chemotaxis is controlled by an unusual phosphorelay network. J Bacteriol 2021; 204:e0052721. [PMID: 34843377 DOI: 10.1128/jb.00527-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Azorhizobium caulinodans is a nitrogen-fixing bacterium that forms root nodules on its host legume, Sesbania rostrata. This agriculturally significant symbiotic relationship is important in lowland rice cultivation, and allows for nitrogen fixation under flood conditions. Chemotaxis plays an important role in bacterial colonization of the rhizosphere. Plant roots release chemical compounds that are sensed by bacteria, triggering chemotaxis along a concentration gradient toward the roots. This gives motile bacteria a significant competitive advantage during root surface colonization. Although plant-associated bacterial genomes often encode multiple chemotaxis systems, A. caulinodans appears to encode only one. The che cluster on the A. caulinodans genome contains cheA, cheW, cheY2, cheB, and cheR. Two other chemotaxis genes, cheY1 and cheZ, are located independently from the che operon. Both CheY1 and CheY2 are involved in chemotaxis, with CheY1 being the predominant signaling protein. A. caulinodans CheA contains an unusual set of C-terminal domains: a CheW-like/Receiver pair (termed W2-Rec), follows the more common single CheW-like domain. W2-Rec impacts both chemotaxis and CheA function. We found a preference for transfer of phosphoryl groups from CheA to CheY2, rather than to W2-Rec or CheY1, which appears to be involved in flagellar motor binding. Furthermore, we observed increased phosphoryl group stabilities on CheY1 compared to CheY2 or W2-Rec. Finally, CheZ enhanced dephosphorylation of CheY2 substantially more than CheY1, but had no effect on the dephosphorylation rate of W2-Rec. This network of phosphotransfer reactions highlights a previously uncharacterized scheme for regulation of chemotactic responses. IMPORTANCE Chemotaxis allows bacteria to move towards nutrients and away from toxins in their environment. Chemotactic movement provides a competitive advantage over non-specific motion. CheY is an essential mediator of the chemotactic response with phosphorylated and unphosphorylated forms of CheY differentially interacting with the flagellar motor to change swimming behavior. Previously established schemes of CheY dephosphorylation include action of a phosphatase and/or transfer of the phosphoryl group to another receiver domain that acts as a sink. Here, we propose A. caulinodans uses a concerted mechanism in which the Hpt domain of CheA, CheY2, and CheZ function together as a dual sink system to rapidly reset chemotactic signaling. To the best of our knowledge, this mechanism is unlike any that have previously been evaluated. Chemotaxis systems that utilize both receiver and Hpt domains as phosphate sinks likely occur in other bacterial species.
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Ortet P, Fochesato S, Bitbol AF, Whitworth DE, Lalaouna D, Santaella C, Heulin T, Achouak W, Barakat M. Evolutionary history expands the range of signaling interactions in hybrid multikinase networks. Sci Rep 2021; 11:11763. [PMID: 34083699 PMCID: PMC8175716 DOI: 10.1038/s41598-021-91260-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 05/19/2021] [Indexed: 12/02/2022] Open
Abstract
Two-component systems (TCSs) are ubiquitous signaling pathways, typically comprising a sensory histidine kinase (HK) and a response regulator, which communicate via intermolecular kinase-to-receiver domain phosphotransfer. Hybrid HKs constitute non-canonical TCS signaling pathways, with transmitter and receiver domains within a single protein communicating via intramolecular phosphotransfer. Here, we report how evolutionary relationships between hybrid HKs can be used as predictors of potential intermolecular and intramolecular interactions (‘phylogenetic promiscuity’). We used domain-swap genes chimeras to investigate the specificity of phosphotransfer within hybrid HKs of the GacS–GacA multikinase network of Pseudomonas brassicacearum. The receiver domain of GacS was replaced with those from nine donor hybrid HKs. Three chimeras with receivers from other hybrid HKs demonstrated correct functioning through complementation of a gacS mutant, which was dependent on strains having a functional gacA. Formation of functional chimeras was predictable on the basis of evolutionary heritage, and raises the possibility that HKs sharing a common ancestor with GacS might remain components of the contemporary GacS network. The results also demonstrate that understanding the evolutionary heritage of signaling domains in sophisticated networks allows their rational rewiring by simple domain transplantation, with implications for the creation of designer networks and inference of functional interactions.
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Affiliation(s)
- Philippe Ortet
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMIRE, 13108, Saint Paul-Lez-Durance, France
| | - Sylvain Fochesato
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMIRE, 13108, Saint Paul-Lez-Durance, France
| | - Anne-Florence Bitbol
- CNRS, Institut de Biologie Paris-Seine, Laboratoire Jean Perrin (UMR8237), Sorbonne Université, 75005, Paris, France.,Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - David E Whitworth
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Ceredigion, SY23 3DD, UK
| | - David Lalaouna
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMIRE, 13108, Saint Paul-Lez-Durance, France.,CNRS, ARN UPR 9002, Université de Strasbourg, 67000, Strasbourg, France
| | - Catherine Santaella
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMIRE, 13108, Saint Paul-Lez-Durance, France
| | - Thierry Heulin
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMIRE, 13108, Saint Paul-Lez-Durance, France
| | - Wafa Achouak
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMIRE, 13108, Saint Paul-Lez-Durance, France
| | - Mohamed Barakat
- Aix Marseille Univ, CEA, CNRS, BIAM, LEMIRE, 13108, Saint Paul-Lez-Durance, France.
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Bourret RB, Kennedy EN, Foster CA, Sepúlveda VE, Goldman WE. A Radical Reimagining of Fungal Two-Component Regulatory Systems. Trends Microbiol 2021; 29:883-893. [PMID: 33853736 DOI: 10.1016/j.tim.2021.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 11/17/2022]
Abstract
Bacterial two-component regulatory systems (TCSs) mediate signal transduction by transferring phosphoryl groups between sensor kinase and response regulator proteins, sometimes using intermediary histidine-phosphotransferase (Hpt) domains to form multistep phosphorelays. Because (i) almost all known fungal sensor kinases exhibit a domain architecture characteristic of bacterial TCS phosphorelays, (ii) all known fungal Hpts are stand-alone proteins suited to shuttle between cytoplasm and nucleus, and (iii) the best-characterized fungal TCS is a canonical phosphorelay, it is widely assumed that most or all fungal TCSs function via phosphorelays. However, fungi generally encode more sensor kinases than Hpts or response regulators, leading to a disparity between putative phosphorelay inputs and outputs. The simplest resolution of this paradox is to hypothesize that most fungal sensor kinases do not participate in phosphorelays. Reimagining how fungal TCSs might function leads to multiple testable predictions.
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Affiliation(s)
- Robert B Bourret
- Department of Microbiology & Immunology, University of North Carolina, Chapel Hill, NC 27599-7290, USA.
| | - Emily N Kennedy
- Department of Microbiology & Immunology, University of North Carolina, Chapel Hill, NC 27599-7290, USA
| | - Clay A Foster
- Department of Microbiology & Immunology, University of North Carolina, Chapel Hill, NC 27599-7290, USA
| | - Victoria E Sepúlveda
- Department of Microbiology & Immunology, University of North Carolina, Chapel Hill, NC 27599-7290, USA
| | - William E Goldman
- Department of Microbiology & Immunology, University of North Carolina, Chapel Hill, NC 27599-7290, USA
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Orphan Hybrid Histidine Protein Kinase SinK Acts as a Signal Integrator To Fine-Tune Multicellular Behavior in Myxococcus xanthus. J Bacteriol 2019; 201:JB.00561-18. [PMID: 30617244 DOI: 10.1128/jb.00561-18] [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: 09/11/2018] [Accepted: 12/21/2018] [Indexed: 11/20/2022] Open
Abstract
His-Asp phosphorelay (also known as two-component signal transduction) proteins are the predominant mechanism used in most bacteria to control behavior in response to changing environmental conditions. In addition to systems consisting of a simple two-component system utilizing an isolated histidine kinase/response regulator pair, some bacteria are enriched in histidine kinases that serve as signal integration proteins; these kinases are usually characterized by noncanonical domain architecture, and the responses that they regulate may be difficult to identify. The environmental bacterium Myxococcus xanthus is highly enriched in these noncanonical histidine kinases. M. xanthus is renowned for a starvation-induced multicellular developmental program in which some cells are induced to aggregate into fruiting bodies and then differentiate into environmentally resistant spores. Here, we characterize the M. xanthus orphan hybrid histidine kinase SinK (Mxan_4465), which consists of a histidine kinase transmitter followed by two receiver domains (REC1 and REC2). Nonphosphorylatable sinK mutants were analyzed under two distinct developmental conditions and using a new high-resolution developmental assay. These assays revealed that SinK autophosphorylation and REC1 impact the onset of aggregation and/or the mobility of aggregates, while REC2 impacts sporulation efficiency. SinK activity is controlled by a genus-specific hypothetical protein (SinM; Mxan_4466). We propose that SinK serves to fine-tune fruiting body morphology in response to environmental conditions.IMPORTANCE Biofilms are multicellular communities of microorganisms that play important roles in host disease or environmental biofouling. Design of preventative strategies to block biofilms depends on understanding the molecular mechanisms used by microorganisms to build them. The production of biofilms in bacteria often involves two-component signal transduction systems in which one protein component (a kinase) detects an environmental signal and, through phosphotransfer, activates a second protein component (a response regulator) to change the transcription of genes necessary to produce a biofilm. We show that an atypical kinase, SinK, modulates several distinct stages of specialized biofilm produced by the environmental bacterium Myxococcus xanthus SinK likely integrates multiple signals to fine-tune biofilm formation in response to distinct environmental conditions.
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Kara A, Vickers M, Swain M, Whitworth DE, Fernandez-Fuentes N. MetaPred2CS: a sequence-based meta-predictor for protein-protein interactions of prokaryotic two-component system proteins. Bioinformatics 2016; 32:3339-3341. [PMID: 27378293 DOI: 10.1093/bioinformatics/btw403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 06/20/2016] [Indexed: 11/14/2022] Open
Abstract
MOTIVATION Two-component systems (TCS) are the main signalling pathways of prokaryotes, and control a wide range of biological phenomena. Their functioning depends on interactions between TCS proteins, the specificity of which is poorly understood. RESULTS The MetaPred2CS web-server interfaces a sequence-based meta-predictor specifically designed to predict pairing of the histidine kinase and response-regulator proteins forming TCSs. MetaPred2CS integrates six sequence-based methods using a support vector machine classifier and has been intensively tested under different benchmarking conditions: (i) species specific gene sets; (ii) neighbouring versus orphan pairs; and (iii) k-fold cross validation on experimentally validated datasets. AVAILABILITY AND IMPLEMENTATION Web server at: http://metapred2cs.ibers.aber.ac.uk/, Source code: https://github.com/martinjvickers/MetaPred2CS or implemented as Virtual Machine at: http://metapred2cs.ibers.aber.ac.uk/download CONTACT: naf4@aber.ac.ukSupplementary information: Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Altan Kara
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth SY23 3EB, UK
| | - Martin Vickers
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth SY23 3EB, UK
| | - Martin Swain
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth SY23 3EB, UK
| | - David E Whitworth
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth SY23 3EB, UK
| | - Narcis Fernandez-Fuentes
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth SY23 3EB, UK
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7
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Borland S, Prigent-Combaret C, Wisniewski-Dyé F. Bacterial hybrid histidine kinases in plant-bacteria interactions. MICROBIOLOGY-SGM 2016; 162:1715-1734. [PMID: 27609064 DOI: 10.1099/mic.0.000370] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Two-component signal transduction systems are essential for many bacteria to maintain homeostasis and adapt to environmental changes. Two-component signal transduction systems typically involve a membrane-bound histidine kinase that senses stimuli, autophosphorylates in the transmitter region and then transfers the phosphoryl group to the receiver domain of a cytoplasmic response regulator that mediates appropriate changes in bacterial physiology. Although usually found on distinct proteins, the transmitter and receiver modules are sometimes fused into a so-called hybrid histidine kinase (HyHK). Such structure results in multiple phosphate transfers that are believed to provide extra-fine-tuning mechanisms and more regulatory checkpoints than classical phosphotransfers. HyHK-based regulation may be crucial for finely tuning gene expression in a heterogeneous environment such as the rhizosphere, where intricate plant-bacteria interactions occur. In this review, we focus on roles fulfilled by bacterial HyHKs in plant-associated bacteria, providing recent findings on the mechanistic of their signalling properties. Recent insights into understanding additive regulatory properties fulfilled by the tethered receiver domain of HyHKs are also addressed.
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Affiliation(s)
- Stéphanie Borland
- Université de Lyon, Université Lyon 1, Ecologie Microbienne, CNRS UMR5557, INRA UMR1418, Villeurbanne, France
| | - Claire Prigent-Combaret
- Université de Lyon, Université Lyon 1, Ecologie Microbienne, CNRS UMR5557, INRA UMR1418, Villeurbanne, France
| | - Florence Wisniewski-Dyé
- Université de Lyon, Université Lyon 1, Ecologie Microbienne, CNRS UMR5557, INRA UMR1418, Villeurbanne, France
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8
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Molecular Mechanisms of Signaling in Myxococcus xanthus Development. J Mol Biol 2016; 428:3805-30. [DOI: 10.1016/j.jmb.2016.07.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 06/30/2016] [Accepted: 07/08/2016] [Indexed: 11/19/2022]
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9
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Cross Talk Inhibition Nullified by a Receiver Domain Missense Substitution. J Bacteriol 2015; 197:3294-306. [PMID: 26260457 DOI: 10.1128/jb.00436-15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/03/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED In two-component signal transduction, a sensor protein transmitter module controls cognate receiver domain phosphorylation. Most receiver domain sequences contain a small residue (Gly or Ala) at position T + 1 just distal to the essential Thr or Ser residue that forms part of the active site. However, some members of the NarL receiver subfamily have a large hydrophobic residue at position T + 1. Our laboratory previously isolated a NarL mutant in which the T + 1 residue Val-88 was replaced with an orthodox small Ala. This NarL V88A mutant confers a striking phenotype in which high-level target operon expression is both signal (nitrate) and sensor (NarX and NarQ) independent. This suggests that the NarL V88A protein is phosphorylated by cross talk from noncognate sources. Although cross talk was enhanced in ackA null strains that accumulate acetyl phosphate, it persisted in pta ackA double null strains that cannot synthesize this compound and was observed also in narL(+) strains. This indicates that acetate metabolism has complex roles in mediating NarL cross talk. Contrariwise, cross talk was sharply diminished in an arcB barA double null strain, suggesting that the encoded sensors contribute substantially to NarL V88A cross talk. Separately, the V88A substitution altered the in vitro rates of NarL autodephosphorylation and transmitter-stimulated dephosphorylation and decreased affinity for the cognate sensor, NarX. Together, these experiments show that the residue at position T + 1 can strongly influence two distinct aspects of receiver domain function, the autodephosphorylation rate and cross talk inhibition. IMPORTANCE Many bacterial species contain a dozen or more discrete sensor-response regulator two-component systems that convert a specific input into a distinct output pattern. Cross talk, the unwanted transfer of signals between circuits, occurs when a response regulator is phosphorylated inappropriately from a noncognate source. Cross talk is inhibited in part by the high interaction specificity between cognate sensor-response regulator pairs. This study shows that a relatively subtle missense change from Val to Ala nullifies cross talk inhibition, enabling at least two noncognate sensors to enforce an inappropriate output independently of the relevant input.
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10
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He K, Marden JN, Quardokus EM, Bauer CE. Phosphate flow between hybrid histidine kinases CheA₃ and CheS₃ controls Rhodospirillum centenum cyst formation. PLoS Genet 2013; 9:e1004002. [PMID: 24367276 PMCID: PMC3868531 DOI: 10.1371/journal.pgen.1004002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 10/21/2013] [Indexed: 01/21/2023] Open
Abstract
Genomic and genetic analyses have demonstrated that many species contain multiple chemotaxis-like signal transduction cascades that likely control processes other than chemotaxis. The Che3 signal transduction cascade from Rhodospirillum centenum is one such example that regulates development of dormant cysts. This Che-like cascade contains two hybrid response regulator-histidine kinases, CheA3 and CheS3, and a single-domain response regulator CheY3. We demonstrate that cheS3 is epistatic to cheA3 and that only CheS3∼P can phosphorylate CheY3. We further show that CheA3 derepresses cyst formation by phosphorylating a CheS3 receiver domain. These results demonstrate that the flow of phosphate as defined by the paradigm E. coli chemotaxis cascade does not necessarily hold true for non-chemotactic Che-like signal transduction cascades. Bacteria use chemotaxis and chemotaxis-like signal transduction pathways to quickly sense and adapt to a constantly changing environment. The purple photosynthetic bacterium Rhodospirillum centenum is able to withstand long periods of desiccation by forming metabolically dormant cyst cells, the development of which is regulated by the Che3 chemotaxis-like pathway. Using a combination of genetic and biochemical approaches, we demonstrate that hybrid histidine kinase (HHK) CheA3 encoded in the che3 gene cluster is essential for cyst formation while another HHK CheS3 inhibits cyst formation. We further show that the appended receiver domains of these kinases regulate their respective histidine kinase domains and are critical in controlling the timing of cyst formation. Finally, we demonstrate that CheA3 functions upstream of CheS3 and promotes cyst formation by phosphorylating CheS3.
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Affiliation(s)
- Kuang He
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, United States of America
| | - Jeremiah N. Marden
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, United States of America
| | - Ellen M. Quardokus
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Carl E. Bauer
- Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, United States of America
- * E-mail:
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11
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Capra EJ, Perchuk BS, Ashenberg O, Seid CA, Snow HR, Skerker JM, Laub MT. Spatial tethering of kinases to their substrates relaxes evolutionary constraints on specificity. Mol Microbiol 2012; 86:1393-403. [DOI: 10.1111/mmi.12064] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Emily J. Capra
- Department of Biology; Massachusetts Institute of Technology; Cambridge; MA; 02139; USA
| | - Barrett S. Perchuk
- Department of Biology; Massachusetts Institute of Technology; Cambridge; MA; 02139; USA
| | - Orr Ashenberg
- Department of Biology; Massachusetts Institute of Technology; Cambridge; MA; 02139; USA
| | - Charlotte A. Seid
- Department of Biology; Massachusetts Institute of Technology; Cambridge; MA; 02139; USA
| | - Hana R. Snow
- Department of Biology; Massachusetts Institute of Technology; Cambridge; MA; 02139; USA
| | - Jeffrey M. Skerker
- Department of Bioengineering; University of California, Berkeley; Berkeley; CA; 94720; USA
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12
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Abstract
To exist in a wide range of environmental niches, bacteria must sense and respond to a variety of external signals. A primary means by which this occurs is through two-component signal transduction pathways, typically composed of a sensor histidine kinase that receives the input stimuli and then phosphorylates a response regulator that effects an appropriate change in cellular physiology. Histidine kinases and response regulators have an intrinsic modularity that separates signal input, phosphotransfer, and output response; this modularity has allowed bacteria to dramatically expand and diversify their signaling capabilities. Recent work has begun to reveal the molecular basis by which two-component proteins evolve. How and why do orthologous signaling proteins diverge? How do cells gain new pathways and recognize new signals? What changes are needed to insulate a new pathway from existing pathways? What constraints are there on gene duplication and lateral gene transfer? Here, we review progress made in answering these questions, highlighting how the integration of genome sequence data with experimental studies is providing major new insights.
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Affiliation(s)
- Emily J Capra
- Department of Biology, Massachusetts Institute of Technology, Cambridge, 02139, USA
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13
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Schramm A, Lee B, Higgs PI. Intra- and interprotein phosphorylation between two-hybrid histidine kinases controls Myxococcus xanthus developmental progression. J Biol Chem 2012; 287:25060-72. [PMID: 22661709 DOI: 10.1074/jbc.m112.387241] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Histidine-aspartate phosphorelay signaling systems are used to couple stimuli to cellular responses. A hallmark feature is the highly modular signal transmission modules that can form both simple "two-component" systems and sophisticated multicomponent systems that integrate stimuli over time and space to generate coordinated and fine-tuned responses. The deltaproteobacterium Myxococcus xanthus contains a large repertoire of signaling proteins, many of which regulate its multicellular developmental program. Here, we assign an orphan hybrid histidine protein kinase, EspC, to the Esp signaling system that negatively regulates progression through the M. xanthus developmental program. The Esp signal system consists of the hybrid histidine protein kinase, EspA, two serine/threonine protein kinases, and a putative transport protein. We demonstrate that EspC is an essential component of this system because ΔespA, ΔespC, and ΔespA ΔespC double mutants share an identical developmental phenotype. Neither substitution of the phosphoaccepting histidine residue nor deletion of the entire catalytic ATPase domain in EspC produces an in vivo mutant developmental phenotype. In contrast, substitution of the receiver phosphoaccepting residue yields the null phenotype. Although the EspC histidine kinase can efficiently autophosphorylate in vitro, it does not act as a phosphodonor to its own receiver domain. Our in vitro and in vivo analyses suggest the phosphodonor is instead the EspA histidine kinase. We propose EspA and EspC participate in a novel hybrid histidine protein kinase signaling mechanism involving both inter- and intraprotein phosphotransfer. The output of this signaling system appears to be the combined phosphorylated state of the EspA and EspC receiver modules. This system regulates the proteolytic turnover of MrpC, an important regulator of the developmental program.
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Affiliation(s)
- Andreas Schramm
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
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14
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Petters T, Zhang X, Nesper J, Treuner-Lange A, Gomez-Santos N, Hoppert M, Jenal U, Søgaard-Andersen L. The orphan histidine protein kinase SgmT is a c-di-GMP receptor and regulates composition of the extracellular matrix together with the orphan DNA binding response regulator DigR in Myxococcus xanthus. Mol Microbiol 2012; 84:147-65. [PMID: 22394314 PMCID: PMC3509222 DOI: 10.1111/j.1365-2958.2012.08015.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In Myxococcus xanthus the extracellular matrix is essential for type IV pili-dependent motility and starvation-induced fruiting body formation. Proteins of two-component systems including the orphan DNA binding response regulator DigR are essential in regulating the composition of the extracellular matrix. We identify the orphan hybrid histidine kinase SgmT as the partner kinase of DigR. In addition to kinase and receiver domains, SgmT consists of an N-terminal GAF domain and a C-terminal GGDEF domain. The GAF domain is the primary sensor domain. The GGDEF domain binds the second messenger bis-(3′-5′)-cyclic-dimeric-GMP (c-di-GMP) and functions as a c-di-GMP receptor to spatially sequester SgmT. We identify the DigR binding site in the promoter of the fibA gene, which encodes an abundant extracellular matrix metalloprotease. Whole-genome expression profiling experiments in combination with the identified DigR binding site allowed the identification of the DigR regulon and suggests that SgmT/DigR regulates the expression of genes for secreted proteins and enzymes involved in secondary metabolite synthesis. We suggest that SgmT/DigR regulates extracellular matrix composition and that SgmT activity is regulated by two sensor domains with ligand binding to the GAF domain resulting in SgmT activation and c-di-GMP binding to the GGDEF domain resulting in spatial sequestration of SgmT.
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Affiliation(s)
- Tobias Petters
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Str. 10, 35043 Marburg, Germany
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The genetic organisation of prokaryotic two-component system signalling pathways. BMC Genomics 2010; 11:720. [PMID: 21172000 PMCID: PMC3018481 DOI: 10.1186/1471-2164-11-720] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 12/20/2010] [Indexed: 11/16/2022] Open
Abstract
Background Two-component systems (TCSs) are modular and diverse signalling pathways, involving a stimulus-responsive transfer of phosphoryl groups from transmitter to partner receiver domains. TCS gene and domain organisation are both potentially informative regarding biological function, interaction partnerships and molecular mechanisms. However, there is currently little understanding of the relationships between domain architecture, gene organisation and TCS pathway structure. Results Here we classify the gene and domain organisation of TCS gene loci from 1405 prokaryotic replicons (>40,000 TCS proteins). We find that 200 bp is the most appropriate distance cut-off for defining whether two TCS genes are functionally linked. More than 90% of all TCS gene loci encode just one or two transmitter and/or receiver domains, however numerous other geometries exist, often with large numbers of encoded TCS domains. Such information provides insights into the distribution of TCS domains between genes, and within genes. As expected, the organisation of TCS genes and domains is affected by phylogeny, and plasmid-encoded TCS exhibit differences in organisation from their chromosomally-encoded counterparts. Conclusions We provide here an overview of the genomic and genetic organisation of TCS domains, as a resource for further research. We also propose novel metrics that build upon TCS gene/domain organisation data and allow comparisons between genomic complements of TCSs. In particular, 'percentage orphaned TCS genes' (or 'Dissemination') and 'percentage of complex loci' (or 'Sophistication') appear to be useful discriminators, and to reflect mechanistic aspects of TCS organisation not captured by existing metrics.
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Huntley S, Hamann N, Wegener-Feldbrügge S, Treuner-Lange A, Kube M, Reinhardt R, Klages S, Müller R, Ronning CM, Nierman WC, Søgaard-Andersen L. Comparative genomic analysis of fruiting body formation in Myxococcales. Mol Biol Evol 2010; 28:1083-97. [PMID: 21037205 DOI: 10.1093/molbev/msq292] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Genetic programs underlying multicellular morphogenesis and cellular differentiation are most often associated with eukaryotic organisms, but examples also exist in bacteria such as the formation of multicellular, spore-filled fruiting bodies in the order Myxococcales. Most members of the Myxococcales undergo a multicellular developmental program culminating in the formation of spore-filled fruiting bodies in response to starvation. To gain insight into the evolutionary history of fruiting body formation in Myxococcales, we performed a comparative analysis of the genomes and transcriptomes of five Myxococcales species, four of these undergo fruiting body formation (Myxococcus xanthus, Stigmatella aurantiaca, Sorangium cellulosum, and Haliangium ochraceum) and one does not (Anaeromyxobacter dehalogenans). Our analyses show that a set of 95 known M. xanthus development-specific genes--although suffering from a sampling bias--are overrepresented and occur more frequently than an average M. xanthus gene in S. aurantiaca, whereas they occur at the same frequency as an average M. xanthus gene in S. cellulosum and in H. ochraceum and are underrepresented in A. dehalogenans. Moreover, genes for entire signal transduction pathways important for fruiting body formation in M. xanthus are conserved in S. aurantiaca, whereas only a minority of these genes are conserved in A. dehalogenans, S. cellulosum, and H. ochraceum. Likewise, global gene expression profiling of developmentally regulated genes showed that genes that upregulated during development in M. xanthus are overrepresented in S. aurantiaca and slightly underrepresented in A. dehalogenans, S. cellulosum, and H. ochraceum. These comparative analyses strongly indicate that the genetic programs for fruiting body formation in M. xanthus and S. aurantiaca are highly similar and significantly different from the genetic program directing fruiting body formation in S. cellulosum and H. ochraceum. Thus, our analyses reveal an unexpected level of plasticity in the genetic programs for fruiting body formation in the Myxococcales and strongly suggest that the genetic program underlying fruiting body formation in different Myxococcales is not conserved. The evolutionary implications of this finding are discussed.
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Affiliation(s)
- Stuart Huntley
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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Whitworth DE, Cock PJA. Evolution of prokaryotic two-component systems: insights from comparative genomics. Amino Acids 2009; 37:459-66. [DOI: 10.1007/s00726-009-0259-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 02/02/2009] [Indexed: 01/22/2023]
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