Journal articles: 'Phosphorelays'

1

Alves, Rui, Baldiri Salvadó, Ron Milo, Ester Vilaprinyo, and Albert Sorribas. "Maximization of information transmission influences selection of native phosphorelay architectures." PeerJ 9 (June 10, 2021): e11558. http://dx.doi.org/10.7717/peerj.11558.

Full text

Abstract:

Phosphorelays are signal transduction circuits that sense environmental changes and adjust cellular metabolism. Five different circuit architectures account for 99% of all phosphorelay operons annotated in over 9,000 fully sequenced genomes. Here we asked what biological design principles, if any, could explain selection among those architectures in nature. We began by studying kinetically well characterized phosphorelays (Spo0 of Bacillus subtilis and Sln1 of Saccharomyces cerevisiae). We find that natural circuit architecture maximizes information transmission in both cases. We use mathematical models to compare information transmission among the architectures for a realistic range of concentration and parameter values. Mapping experimentally determined phosphorelay protein concentrations onto that range reveals that the native architecture maximizes information transmission in sixteen out of seventeen analyzed phosphorelays. These results suggest that maximization of information transmission is important in the selection of native phosphorelay architectures, parameter values and protein concentrations.

APA, Harvard, Vancouver, ISO, and other styles

2

Csikász-Nagy, Attila, Luca Cardelli, and Orkun S. Soyer. "Response dynamics of phosphorelays suggest their potential utility in cell signalling." Journal of The Royal Society Interface 8, no. 57 (2010): 480–88. http://dx.doi.org/10.1098/rsif.2010.0336.

Full text

Abstract:

Phosphorelays are extended two-component signalling systems found in diverse bacteria, lower eukaryotes and plants. Only few of these systems are characterized, and we still lack a full understanding of their signalling abilities. Here, we aim to achieve a global understanding of phosphorelay signalling and its dynamical properties. We develop a generic model, allowing us to systematically analyse response dynamics under different assumptions. Using this model, we find that the steady-state concentration of phosphorylated protein at the final layer of a phosphorelay is a linearly increasing, but eventually saturating function of the input. In contrast, the intermediate layers can display ultrasensitivity. We find that such ultrasensitivity is a direct result of the phosphorelay biochemistry; shuttling of a single phosphate group from the first to the last layer. The response dynamics of the phosphorelay results in tolerance of cross-talk, especially when it occurs as cross-deactivation. Further, it leads to a high signal-to-noise ratio for the final layer. We find that a relay length of four, which is most commonly observed, acts as a saturating point for these dynamic properties. These findings suggest that phosphorelays could act as a mechanism to reduce noise and effects of cross-talk on the final layer of the relay and enforce its input–response relation to be linear. In addition, our analysis suggests that middle layers of phosphorelays could embed thresholds. We discuss the consequence of these findings in relation to why cells might use phosphorelays along with enzymatic kinase cascades.

APA, Harvard, Vancouver, ISO, and other styles

3

Thomason, P., and R. Kay. "Eukaryotic signal transduction via histidine-aspartate phosphorelay." Journal of Cell Science 113, no. 18 (2000): 3141–50. http://dx.doi.org/10.1242/jcs.113.18.3141.

Full text

Abstract:

Transmembrane signal transduction is a feature common to all eukaryotic and prokaryotic cells. We now understand that a subset of the signalling mechanisms used by eukaryotes and prokaryotes are not just similar in principle, but actually use homologous proteins. These are the histidine-aspartate phosphorelays, signalling systems of eubacterial origin, now known to be widespread in eukaryotes outside the animal kingdom. Genome projects are revealing that His-Asp phosphorelays are present as multigene families in lower eukaryotes and in plants. A major challenge is to understand how these ‘novel’ signal transduction systems form integrated networks with the more familiar signalling mechanisms also present in eukaryotic cells. Already, phosphorelays have been characterised that regulate MAP kinase cascades and the cAMP/PKA pathway. The probable absence of His-Asp phosphorelays from animals has generated interest in their potential as targets for anti-microbial therapy, including antifungals. Recent findings suggest that this approach holds promise.

APA, Harvard, Vancouver, ISO, and other styles

4

Koppenhöfer, Sonja, and Andrew S. Lang. "Interactions among Redox Regulators and the CtrA Phosphorelay in Dinoroseobacter shibae and Rhodobacter capsulatus." Microorganisms 8, no. 4 (2020): 562. http://dx.doi.org/10.3390/microorganisms8040562.

Full text

Abstract:

Bacteria employ regulatory networks to detect environmental signals and respond appropriately, often by adjusting gene expression. Some regulatory networks influence many genes, and many genes are affected by multiple regulatory networks. Here, we investigate the extent to which regulatory systems controlling aerobic–anaerobic energetics overlap with the CtrA phosphorelay, an important system that controls a variety of behavioral processes, in two metabolically versatile alphaproteobacteria, Dinoroseobacter shibae and Rhodobacter capsulatus. We analyzed ten available transcriptomic datasets from relevant regulator deletion strains and environmental changes. We found that in D. shibae, the CtrA phosphorelay represses three of the four aerobic–anaerobic Crp/Fnr superfamily regulator-encoding genes (fnrL, dnrD, and especially dnrF). At the same time, all four Crp/Fnr regulators repress all three phosphorelay genes. Loss of dnrD or dnrF resulted in activation of the entire examined CtrA regulon, regardless of oxygen tension. In R. capsulatus FnrL, in silico and ChIP-seq data also suggested regulation of the CtrA regulon, but it was only with loss of the redox regulator RegA where an actual transcriptional effect on the CtrA regulon was observed. For the first time, we show that there are complex interactions between redox regulators and the CtrA phosphorelays in these bacteria and we present several models for how these interactions might occur.

APA, Harvard, Vancouver, ISO, and other styles

5

Chen, Y. Erin, Christos G. Tsokos, Emanuele G. Biondi, Barrett S. Perchuk, and Michael T. Laub. "Dynamics of Two Phosphorelays Controlling Cell Cycle Progression in Caulobacter crescentus." Journal of Bacteriology 191, no. 24 (2009): 7417–29. http://dx.doi.org/10.1128/jb.00992-09.

Full text

Abstract:

ABSTRACT In Caulobacter crescentus, progression through the cell cycle is governed by the periodic activation and inactivation of the master regulator CtrA. Two phosphorelays, each initiating with the histidine kinase CckA, promote CtrA activation by driving its phosphorylation and by inactivating its proteolysis. Here, we examined whether the CckA phosphorelays also influence the downregulation of CtrA. We demonstrate that CckA is bifunctional, capable of acting as either a kinase or phosphatase to drive the activation or inactivation, respectively, of CtrA. By identifying mutations that uncouple these two activities, we show that CckA's phosphatase activity is important for downregulating CtrA prior to DNA replication initiation in vivo but that other phosphatases may exist. Our results demonstrate that cell cycle transitions in Caulobacter require and are likely driven by the toggling of CckA between its kinase and phosphatase states. More generally, our results emphasize how the bifunctional nature of histidine kinases can help switch cells between mutually exclusive states.

APA, Harvard, Vancouver, ISO, and other styles

6

Schaller, G. Eric, Joseph J. Kieber, and Shin-Han Shiu. "Two-Component Signaling Elements and Histidyl-Aspartyl Phosphorelays†." Arabidopsis Book 6 (January 2008): e0112. http://dx.doi.org/10.1199/tab.0112.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Chauhan, Neeraj. "Two-component phosphorelays in fungal mitochondria and beyond." Mitochondrion 22 (May 2015): 60–65. http://dx.doi.org/10.1016/j.mito.2015.03.003.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Tierrez, Alberto, and Francisco García-del Portillo. "The Salmonella Membrane Protein IgaA Modulates the Activity of the RcsC-YojN-RcsB and PhoP-PhoQ Regulons." Journal of Bacteriology 186, no. 22 (2004): 7481–89. http://dx.doi.org/10.1128/jb.186.22.7481-7489.2004.

Full text

Abstract:

ABSTRACT The Salmonella enterica serovar Typhimurium membrane protein IgaA and the PhoP-PhoQ two-component system are used by this pathogen to attenuate the intracellular growth rate within fibroblasts. IgaA has also recently been shown to contribute to virulence by exerting tight repression of the RcsC-YojN-RcsB phosphorelay in host tissues. Here we show that loss of repression of the RcsC-YojN-RcsB system, linked to an R188H mutation in the IgaA protein (igaA1 allele), is accompanied by altered expression of PhoP-PhoQ-activated (pag) genes. The changes in gene expression were different depending on the specific pag gene analyzed. Thus, transcription of ugd, which is required for lipopolysaccharide modification and colanic acid capsule synthesis, was enhanced in the igaA1 mutant. RcsB and its coregulator RcsA promoted this alteration in a PhoP-PmrA-independent manner. Unlike ugd, activation of the RcsC-YojN-RcsB phosphorelay negatively affected the expression of all other pag genes tested. In this case, RcsB alone was responsible for this effect. We also found that PhoP, but not PmrA, negatively modulates the expression of gmm, a gene required for colanic acid synthesis that is regulated positively by RcsC-YojN-RcsB. Finally, it was observed that the fine regulation of pag genes exerted by RcsB requires the RpoS protein and that an active RcsB, but not RcsA, diminishes expression of the phoP gene. These data support the hypothesis that in Salmonella there is an intimate regulatory circuit between the PhoP-PhoQ and RcsC-YojN-RcsB phosphorelays, which is revealed only when the RcsC-YojN-RcsB signaling route is derepressed. Consistent with the phenotypes observed in fibroblast cells, IgaA is predicted to favor expression of the entire PhoP-PhoQ regulon based on its repression of the RcsC-YojN-RcsB phosphorelay.

APA, Harvard, Vancouver, ISO, and other styles

9

Kothamachu, Varun B., Elisenda Feliu, Carsten Wiuf, Luca Cardelli, and Orkun S. Soyer. "Phosphorelays Provide Tunable Signal Processing Capabilities for the Cell." PLoS Computational Biology 9, no. 11 (2013): e1003322. http://dx.doi.org/10.1371/journal.pcbi.1003322.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Knudsen, Michael, Elisenda Feliu, and Carsten Wiuf. "Exact analysis of intrinsic qualitative features of phosphorelays using mathematical models." Journal of Theoretical Biology 300 (May 2012): 7–18. http://dx.doi.org/10.1016/j.jtbi.2012.01.007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Karniol, Baruch, and Richard D. Vierstra. "The HWE Histidine Kinases, a New Family of Bacterial Two-Component Sensor Kinases with Potentially Diverse Roles in Environmental Signaling." Journal of Bacteriology 186, no. 2 (2004): 445–53. http://dx.doi.org/10.1128/jb.186.2.445-453.2004.

Full text

Abstract:

ABSTRACT Two-component signal transduction pathways play a major role in the response of bacteria to external cues. These pathways are initiated by large collection of histidine kinases (HKs) containing a sensor domain that perceives the environmental signal followed by an HK domain that triggers a histidine-aspartate phosphorelay. Previous phylogenetic analyses identified 11 major families of two-component HKs by comparing signature motifs within the HK domain. Here we describe a new family with homology to Agrobacterium tumefaciens BphP2, an HK first discovered by the presence of a phytochrome sensor domain involved in light perception. Members of this sensor HK family differ from most others by the absence of a recognizable F box and the presence of several uniquely conserved residues, including a histidine in the N box and a tryptophan-X-glutamic acid sequence in the G1 box, which we have used to define the family (HWE). At least 81 members were identified in a variety of α- and γ-proteobacteria, with a significant enrichment in the Rhizobiaceae family. Several representatives were shown to have HK activity in vitro, supporting their proposed participation in phosphorelays. One or more domains related to signal transduction were evident N-terminal to the HK domain, including chemotactic methyltransferase domains, suggesting that this family has multiple roles in environmental signaling. The discovery of the HWE family further extends the diversity within the HK superfamily and expands the importance of two-component signaling in bacteria.

APA, Harvard, Vancouver, ISO, and other styles

12

Hnatuszko-Konka, Katarzyna, Aneta Gerszberg, Izabela Weremczuk-Jeżyna, and Izabela Grzegorczyk-Karolak. "Cytokinin Signaling and De Novo Shoot Organogenesis." Genes 12, no. 2 (2021): 265. http://dx.doi.org/10.3390/genes12020265.

Full text

Abstract:

The ability to restore or replace injured tissues can be undoubtedly named among the most spectacular achievements of plant organisms. One of such regeneration pathways is organogenesis, the formation of individual organs from nonmeristematic tissue sections. The process can be triggered in vitro by incubation on medium supplemented with phytohormones. Cytokinins are a class of phytohormones demonstrating pleiotropic effects and a powerful network of molecular interactions. The present study reviews existing knowledge on the possible sequence of molecular and genetic events behind de novo shoot organogenesis initiated by cytokinins. Overall, the review aims to collect reactions encompassed by cytokinin primary responses, starting from phytohormone perception by the dedicated receptors, to transcriptional reprogramming of cell fate by the last module of multistep-phosphorelays. It also includes a brief reminder of other control mechanisms, such as epigenetic reprogramming.

APA, Harvard, Vancouver, ISO, and other styles

13

Héricourt, François, Mélanie Larcher, Françoise Chefdor, et al. "New Insight into HPts as Hubs in Poplar Cytokinin and Osmosensing Multistep Phosphorelays: Cytokinin Pathway Uses Specific HPts." Plants 8, no. 12 (2019): 591. http://dx.doi.org/10.3390/plants8120591.

Full text

Abstract:

We have previously identified proteins in poplar which belong to an osmosensing (OS) signaling pathway, called a multistep phosphorelay (MSP). The MSP comprises histidine-aspartate kinases (HK), which act as membrane receptors; histidine phosphotransfer (HPt) proteins, which act as phosphorelay proteins; and response regulators (RR), some of which act as transcription factors. In this study, we identified the HK proteins homologous to the Arabidopsis cytokinin (CK) receptors, which are first partners in the poplar cytokinin MSP, and focused on specificity of these two MSPs (CK and OS), which seem to share the same pool of HPt proteins. Firstly, we isolated five CK HKs from poplar which are homologous to Arabidopsis AHK2, AHK3, and AHK4, namely, HK2, HK3a, HK3b, HK4a, HK4b. These HKs were shown to be functional kinases, as observed in a functional complementation of a yeast HK deleted strain. Moreover, one of these HKs, HK4a, was shown to have kinase activity dependent on the presence of CK. Exhaustive interaction tests between these five CK HKs and the 10 HPts characterized in poplar were performed using two-hybrid and BiFC experiments. The resulting partnership was compared to that previously identified between putative osmosensors HK1a/1b and HPt proteins. Finally, in planta coexpression analysis of genes encoding these potential partners revealed that almost all HPts are coexpressed with CK HKs in four different poplar organs. Overall, these results allowed us to unravel the common and specific partnerships existing between OS and CK MSP in Populus.

APA, Harvard, Vancouver, ISO, and other styles

14

Zelman, Alice K., and Gerald Alan Berkowitz. "Plant Elicitor Peptide (Pep) Signaling and Pathogen Defense in Tomato." Plants 12, no. 15 (2023): 2856. http://dx.doi.org/10.3390/plants12152856.

Full text

Abstract:

Endogenous signaling compounds are intermediaries in signaling pathways that plants use to respond to the perception of harmful and beneficial organisms. The plant elicitor peptides (Peps) of plants are important endogenous signaling molecules that induce elements of defense responses such as hormone production, increased expression of defensive genes, the activation of phosphorelays, and the induction of cell secondary messenger synthesis. The processes by which Peps confer resistance to pathogenic microorganisms have been extensively studied in Arabidopsis but are less known in crop plants. Tomato and many other solanaceous plants have an endogenous signaling polypeptide, systemin, that is involved in the defense against herbivorous insects and necrotrophic pathogens. This paper explores the similarity of the effects and chemical properties of Pep and systemin in tomato. Additionally, the relationship of the Pep receptor and systemin receptors is explored, and the identification of a second tomato Pep receptor in the literature is called into question. We suggest future directions for research on Pep signaling in solanaceous crops during interactions with microbes.

APA, Harvard, Vancouver, ISO, and other styles

15

Williams, Corinne L., and Peggy A. Cotter. "Autoregulation Is Essential for Precise Temporal and Steady-State Regulation by the Bordetella BvgAS Phosphorelay." Journal of Bacteriology 189, no. 5 (2006): 1974–82. http://dx.doi.org/10.1128/jb.01684-06.

Full text

Abstract:

ABSTRACT The Bordetella BvgAS virulence control system is prototypical of phosphorelays that use a polydomain sensor and a response regulator to control gene expression in response to environmental cues. BvgAS controls the expression of at least three distinct phenotypic phases (Bvg−, Bvgi, and Bvg+) by differentially regulating the expression of at least four classes of genes. Among the loci regulated by BvgAS is bvgAS itself. We investigated the role of autoregulation in the ability of BvgAS to control multiple gene expression patterns in a temporal and steady-state manner by constructing Bordetella bronchiseptica strains in which the bvgAS promoter was replaced with constitutively active promoters. Our results show that positive autoregulation of bvgAS transcription is required for the temporal expression of multiple phenotypic phases that occurs in response to a shift from Bvg−-phase conditions to Bvg+-phase conditions. Autoregulation was also shown to contribute to steady-state regulation; it influences the sensitivity of the system in response to subtle differences in signal intensity. In addition, considered in relation to BvgA and BvgS activities demonstrated in vitro, our results provide insight into how BvgA and BvgS function mechanistically.

APA, Harvard, Vancouver, ISO, and other styles

16

Wegener-Feldbrügge, Sigrun, and Lotte Søgaard-Andersen. "The Atypical Hybrid Histidine Protein Kinase RodK in Myxococcus xanthus: Spatial Proximity Supersedes Kinetic Preference in Phosphotransfer Reactions." Journal of Bacteriology 191, no. 6 (2009): 1765–76. http://dx.doi.org/10.1128/jb.01405-08.

Full text

Abstract:

ABSTRACT Many proteins of two-component signal transduction systems (TCS) have domain structures that do not comply with a phosphate flow as observed in linear TCS, phosphorelays, or simple branched pathways. An example is RodK, which is essential for fruiting body formation in Myxococcus xanthus and, in addition to a sensor domain, consists of a kinase domain and three receiver domains (RodK-R1, -R2, and -R3), all of which are functionally important. We identified the RokA response regulator as part of the RodK pathway. In vitro the isolated RodK kinase domain engages in phosphotransfer to RodK-R3 and RokA, with a kinetic preference for RokA. However, in the context of the full-length protein, the RodK kinase domain has a preference for phosphotransfer to RodK-R3 over RokA. We suggest that in full-length RodK, the spatial proximity of the RodK kinase domain and RodK-R3 compensate for the kinetic preference of the isolated kinase domain for RokA. Thus, the kinetic preference observed using an isolated kinase domain of a hybrid kinase does not necessarily reflect the phosphotransfer preference of the full-length protein. We speculate that the phosphorylation status of RodK-R1 and RodK-R2 determines whether RodK engages in phosphotransfer to RodK-R3 or RokA in vivo.

APA, Harvard, Vancouver, ISO, and other styles

17

AZUMA, Nobuhiro, Kyoko KANAMARU, Akinori MATSUSHIKA, et al. "In VitroAnalysis of His-Asp Phosphorelays inAspergillus nidulans: The First Direct Biochemical Evidence for the Existence of His-Asp Phosphotransfer Systems in Filamentous Fungi." Bioscience, Biotechnology, and Biochemistry 71, no. 10 (2007): 2493–502. http://dx.doi.org/10.1271/bbb.70292.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

de Jong, Imke G., Jan-Willem Veening, and Oscar P. Kuipers. "Heterochronic Phosphorelay Gene Expression as a Source of Heterogeneity in Bacillus subtilis Spore Formation." Journal of Bacteriology 192, no. 8 (2010): 2053–67. http://dx.doi.org/10.1128/jb.01484-09.

Full text

Abstract:

ABSTRACT In response to limiting nutrient sources and cell density signals, Bacillus subtilis can differentiate and form highly resistant endospores. Initiation of spore development is governed by the master regulator Spo0A, which is activated by phosphorylation via a multicomponent phosphorelay. Interestingly, only part of a clonal population will enter this developmental pathway, a phenomenon known as sporulation bistability or sporulation heterogeneity. How sporulation heterogeneity is established is largely unknown. To investigate the origins of sporulation heterogeneity, we constructed promoter-green fluorescent protein (GFP) fusions to the main phosphorelay genes and perturbed their expression levels. Using time-lapse fluorescence microscopy and flow cytometry, we showed that expression of the phosphorelay genes is distributed in a unimodal manner. However, single-cell trajectories revealed that phosphorelay gene expression is highly dynamic or “heterochronic” between individual cells and that stochasticity of phosphorelay gene transcription might be an important regulatory mechanism for sporulation heterogeneity. Furthermore, we showed that artificial induction or depletion of the phosphorelay phosphate flow results in loss of sporulation heterogeneity. Our data suggest that sporulation heterogeneity originates from highly dynamic and variable gene activity of the phosphorelay components, resulting in large cell-to-cell variability with regard to phosphate input into the system. These transcriptional and posttranslational differences in phosphorelay activity appear to be sufficient to generate a heterogeneous sporulation signal without the need of the positive-feedback loop established by the sigma factor SigH.

APA, Harvard, Vancouver, ISO, and other styles

19

Eswaramoorthy, Prahathees, Jeffrey Dinh, Daniel Duan, Oleg A. Igoshin, and Masaya Fujita. "Single-cell measurement of the levels and distributions of the phosphorelay components in a population of sporulating Bacillus subtilis cells." Microbiology 156, no. 8 (2010): 2294–304. http://dx.doi.org/10.1099/mic.0.038497-0.

Full text

Abstract:

Upon nutrient starvation, the Gram-positive bacterium Bacillus subtilis switches from growth to sporulation by activating a multicomponent phosphorelay consisting of a major sensor histidine kinase (KinA), two phosphotransferases (Spo0F and Spo0B) and a response regulator (Spo0A). Although the primary sporulation signal(s) produced under starvation conditions is not known, it is believed that the reception of a signal(s) on the sensor kinase results in the activation of autophosphorylation of the enzyme. The phosphorylated kinase transfers the phosphate group to Spo0A via the phosphorelay and thus triggers sporulation. With a combination of quantitative immunoblot analysis, microscopy imaging and computational analysis, here we found that each of the phosphorelay components tested increased gradually over the period of sporulation, and that Spo0F was expressed in a more heterogeneous pattern than KinA and Spo0B in a sporulating cell population. We determined molecule numbers and concentrations of each phosphorelay component under physiological sporulation conditions at the single-cell level. Based on these results, we suggest that successful entry into the sporulation state is manifested by a certain critical level of each phosphorelay component, and thus that only a subpopulation achieves a sufficient intracellular quorum of the phosphorelay components to activate Spo0A and proceed successfully to the entry into sporulation.

APA, Harvard, Vancouver, ISO, and other styles

20

Ansaldi, Mireille, Cécile Jourlin-Castelli, Michèle Lepelletier, Laurence Théraulaz, and Vincent Méjean. "Rapid Dephosphorylation of the TorR Response Regulator by the TorS Unorthodox Sensor in Escherichia coli." Journal of Bacteriology 183, no. 8 (2001): 2691–95. http://dx.doi.org/10.1128/jb.183.8.2691-2695.2001.

Full text

Abstract:

ABSTRACT Induction of the torCAD operon, encoding the trimethylamine N-oxide (TMAO) respiratory system, is tightly controlled by the TorS-TorR phosphorelay system in response to TMAO availability. TorS is an unorthodox sensor that contains three phosphorylation sites and transphosphorylates TorR via a four-step phosphorelay, His443→Asp723→His850→Asp(TorR). In this study, we provide genetic evidence that TorS can dephosphorylate phospho-TorR when TMAO is removed. Dephosphorylation probably occurs by a reverse phosphorelay, Asp(TorR)→His850→Asp723, since His850 and Asp723 are both essential in this process. By using reverse transcriptase PCR, we also show that TMAO removal results in shutoff of toroperon transcription in less than 2 min. Based on our results and on analogy to other phosphorelay signal transduction systems, we propose that reverse phosphotransfer could be a rapid and efficient mechanism to inactivate response regulators.

APA, Harvard, Vancouver, ISO, and other styles

21

Freeman, Jeremy A., and Bonnie L. Bassler. "Sequence and Function of LuxU: a Two-Component Phosphorelay Protein That Regulates Quorum Sensing inVibrio harveyi." Journal of Bacteriology 181, no. 3 (1999): 899–906. http://dx.doi.org/10.1128/jb.181.3.899-906.1999.

Full text

Abstract:

ABSTRACT Vibrio harveyi regulates the expression of bioluminescence (lux) in response to cell density, a phenomenon known as quorum sensing. In V. harveyi, two independent quorum-sensing systems exist, and each produces, detects, and responds to a specific cell density-dependent autoinducer signal. The autoinducers are recognized by two-component hybrid sensor kinases called LuxN and LuxQ, and sensory information from both systems is transduced by a phosphorelay mechanism to the response regulator protein LuxO. Genetic evidence suggests that LuxO-phosphate negatively regulates the expression of luminescence at low cell density in the absence of autoinducers. At high cell density, interaction of the sensors with their cognate autoinducers results in dephosphorylation and inactivation of the LuxO repressor. In the present report, we show that LuxN and LuxQ channel sensory information to LuxO via a newly identified phosphorelay protein that we have named LuxU. LuxU shows sequence similarity to other described phosphorelay proteins, including BvgS, ArcB, and Ypd1. A critical His residue (His 58) of LuxU is required for phosphorelay function.

APA, Harvard, Vancouver, ISO, and other styles

22

Bouchart, Franck, Gilles Boussemart, Anne-France Prouvost, et al. "The Virulence of a Dickeya dadantii 3937 Mutant Devoid of Osmoregulated Periplasmic Glucans Is Restored by Inactivation of the RcsCD-RcsB Phosphorelay." Journal of Bacteriology 192, no. 13 (2010): 3484–90. http://dx.doi.org/10.1128/jb.00143-10.

Full text

Abstract:

ABSTRACT Dickeya dadantii is a pectinolytic phytopathogen enterobacterium that causes soft rot disease on a wide range of plant species. The virulence of D. dadantii involves several factors, including the osmoregulated periplasmic glucans (OPGs) that are general constituents of the envelope of proteobacteria. In addition to the loss of virulence, opg-negative mutants display a pleiotropic phenotype, including decreased motility and increased exopolysaccharide synthesis. A nitrosoguanidine-induced mutagenesis was performed on the opgG strain, and restoration of motility was used as a screen. The phenotype of the opg mutant echoes that of the Rcs system: high level activation of the RcsCD-RcsB phosphorelay is needed to activate exopolysaccharide synthesis and to repress motility, while low level activation is required for virulence in enterobacteria. Here, we show that mutations in the RcsCDB phosphorelay system restored virulence and motility in a D. dadantii opg-negative strain, indicating a relationship between the Rcs phosphorelay and OPGs.

APA, Harvard, Vancouver, ISO, and other styles

23

Walker, Kimberly A., Lauren A. Griggs, Markus Obrist, Addys Bode, R. Patrick Summers, and Virginia L. Miller. "The YsrS Paralog DygS Has the Capacity To Activate Expression of the Yersinia enterocolitica Ysa Type III Secretion System." Journal of Bacteriology 198, no. 12 (2016): 1725–34. http://dx.doi.org/10.1128/jb.00240-16.

Full text

Abstract:

ABSTRACTTheYersinia enterocoliticaYsa type III secretion system (T3SS) is associated with intracellular survival, and, like other characterized T3SSs, it is tightly controlled. Expression of theysagenes is only detected following growth at low temperatures (26°C) and in high concentrations of sodium chloride (290 mM) in the medium. The YsrSTR phosphorelay (PR) system is required forysaexpression and likely responds to NaCl. During our investigations into the Ysr PR system, we discovered that genes YE3578 and YE3579 are remarkably similar toysrRandysrS, respectively, and are probably a consequence of a gene duplication event. The amino acid differences between YE3578 andysrRare primarily clustered into two short regions. The differences between YE3579 andysrSare nearly all located in the periplasmic sensing domain; the cytoplasmic domains are 98% identical. We investigated whether these paralogs were capable of activatingysagene expression. We found that the sensor paralog, named DygS, is capable of compensating for loss ofysrS, but the response regulator paralog, DygR, cannot complement aysrRgene deletion. In addition, YsrR, but not DygR, interacts with the histidine phosphorelay protein YsrT. Thus, DygS likely activatesysagene expression in response to a signal other than NaCl and provides an example of a phosphorelay system in which two sensor kinases feed into the same regulatory pathway.IMPORTANCEAll organisms need mechanisms to promote survival in changing environments. Prokaryotic phosphorelay systems are minimally comprised of a histidine kinase (HK) that senses an extracellular stimulus and a response regulator (RR) but can contain three or more proteins. Through gene duplication, a unique hybrid HK was created. We show that, while the hybrid appears to retain all of the phosphorelay functions, it responds to a different signal than the original. Both HKs transmit the signal to the same RR, which activates a promoter that transcribes a set of genes encoding a type III secretion system (T3SS) whose function is not yet evident. The significance of this work lies in finding that two HKs regulate this T3SS, highlighting its importance.

APA, Harvard, Vancouver, ISO, and other styles

24

Majdalani, Nadim, Michael Heck, Valerie Stout, and Susan Gottesman. "Role of RcsF in Signaling to the Rcs Phosphorelay Pathway in Escherichia coli." Journal of Bacteriology 187, no. 19 (2005): 6770–78. http://dx.doi.org/10.1128/jb.187.19.6770-6778.2005.

Full text

Abstract:

ABSTRACT The rcs phosphorelay pathway components were originally identified as regulators of capsule synthesis. In addition to the transmembrane sensor kinase RcsC, the RcsA coregulator, and the response regulator RcsB, two new components have been characterized, RcsD and RcsF. RcsD, the product of the yojN gene, now renamed rcsD, acts as a phosphorelay between RcsC and RcsB. Transcription of genes for capsule synthesis (cps) requires both RcsA and RcsB; transcription of other promoters, including that for the small RNA RprA, requires only RcsB. RcsF was described as an alternative sensor kinase for RcsB. We have examined the role of RcsF in the activation of both the rprA and cps promoters. We find that a number of signals that lead to activation of the phosphorelay require both RcsF and RcsC; epistasis experiments place RcsF upstream of RcsC. The RcsF sequence is characteristic of lipoproteins, consistent with a role in sensing cell surface perturbation and transmitting this signal to RcsC. Activation of RcsF does not require increased transcription of the gene, suggesting that modification of the RcsF protein may act as an activating signal. Signals from RcsC require RcsD to activate RcsB. Sequencing of an rcsC allele, rcsC137, that leads to high-level constitutive expression of both cps and rprA suggests that the response regulator domain of RcsC plays a role in negatively regulating the kinase activity of RcsC. The phosphorelay and the variation in the activation mechanism (dependent upon or independent of RcsA) provide multiple steps for modulating the output from this system.

APA, Harvard, Vancouver, ISO, and other styles

25

Hoch, James A. "Two-component and phosphorelay signal transduction." Current Opinion in Microbiology 3, no. 2 (2000): 165–70. http://dx.doi.org/10.1016/s1369-5274(00)00070-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Varughese, K. "Molecular recognition of bacterial phosphorelay proteins." Current Opinion in Microbiology 5, no. 2 (2002): 142–48. http://dx.doi.org/10.1016/s1369-5274(02)00305-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Sato, Naoto, Hiroyuki Kawahara, Akio Toh-e, and Tatsuya Maeda. "Phosphorelay-Regulated Degradation of the Yeast Ssk1p Response Regulator by the Ubiquitin-Proteasome System." Molecular and Cellular Biology 23, no. 18 (2003): 6662–71. http://dx.doi.org/10.1128/mcb.23.18.6662-6671.2003.

Full text

Abstract:

ABSTRACT In Saccharomyces cerevisiae, a phosphorelay signal transduction pathway composed of Sln1p, Ypd1p, and Ssk1p, which are homologous to bacterial two-component signal transducers, is involved in the osmosensing mechanism. In response to high osmolarity, the phosphorelay system is inactivated and Ssk1p remains unphosphorylated. Unphosphorylated Ssk1p binds to and activates the Ssk2p mitogen-activated protein (MAP) kinase kinase kinase, which in turn activates the downstream components of the high-osmolarity glycerol response (HOG) MAP kinase cascade. Here, we report a novel inactivation mechanism for Ssk1p involving degradation by the ubiquitin-proteasome system. Degradation is regulated by the phosphotransfer from Ypd1p to Ssk1p, insofar as unphosphorylated Ssk1p is degraded more rapidly than phosphorylated Ssk1p. Ubc7p/Qri8p, an endoplasmic reticulum-associated ubiquitin-conjugating enzyme, is involved in the phosphorelay-regulated degradation of Ssk1p. In ubc7Δ cells in which the degradation is hampered, the dephosphorylation and/or inactivation process of the Hog1p MAP kinase is delayed compared with wild-type cells after the hyperosmotic treatment. Our results indicate that unphosphorylated Ssk1p is selectively degraded by the Ubc7p-dependent ubiquitin-proteasome system and that this mechanism downregulates the HOG pathway after the completion of the osmotic adaptation.

APA, Harvard, Vancouver, ISO, and other styles

28

Castanié-Cornet, Marie-Pierre, Kaymeuang Cam, and Annick Jacq. "RcsF Is an Outer Membrane Lipoprotein Involved in the RcsCDB Phosphorelay Signaling Pathway in Escherichia coli." Journal of Bacteriology 188, no. 12 (2006): 4264–70. http://dx.doi.org/10.1128/jb.00004-06.

Full text

Abstract:

ABSTRACT The RcsCDB signal transduction system is an atypical His-Asp phosphorelay conserved in γ-proteobacteria. Besides the three proteins directly involved in the phosphorelay, two proteins modulate the activity of the system. One is RcsA, which can stimulate the activity of the response regulator RcsB independently of the phosphorelay to regulate a subset of RcsB targets. The other is RcsF, a putative outer membrane lipoprotein mediating the signaling to the sensor RcsC. How RcsF transduces the signal to RcsC is unknown. Although the molecular and physiological signals remain to be identified, the common feature among the reported Rcs-activating conditions is perturbation of the envelope. As an initial step to explore the RcsF-RcsC functional relationship, we demonstrate that RcsF is an outer membrane lipoprotein oriented towards the periplasm. We also report that a null mutation in surA, a gene required for correct folding of periplasmic proteins, activates the Rcs pathway through RcsF. In contrast, activation of this pathway by overproduction of the membrane chaperone-like protein DjlA does not require RcsF. Conversely, activation of the pathway by RcsF overproduction does not require DjlA either, indicating the existence of two independent signaling pathways toward RcsC.

APA, Harvard, Vancouver, ISO, and other styles

29

Farris, Carol, Sarah Sanowar, Martin W. Bader, Richard Pfuetzner, and Samuel I. Miller. "Antimicrobial Peptides Activate the Rcs Regulon through the Outer Membrane Lipoprotein RcsF." Journal of Bacteriology 192, no. 19 (2010): 4894–903. http://dx.doi.org/10.1128/jb.00505-10.

Full text

Abstract:

ABSTRACT Salmonella enterica species are exposed to envelope stresses due to their environmental and infectious lifestyles. Such stresses include amphipathic cationic antimicrobial peptides (CAMPs), and resistance to these peptides is an important property for microbial virulence for animals. Bacterial mechanisms used to sense and respond to CAMP-induced envelope stress include the RcsFCDB phosphorelay, which contributes to survival from polymyxin B exposure. The Rcs phosphorelay includes two inner membrane (IM) proteins, RcsC and RcsD; the response regulator RcsB; the accessory coregulator RcsA; and an outer membrane bound lipoprotein, RcsF. Transcriptional activation of the Rcs regulon occurred within minutes of exposure to CAMP and during the first detectable signs of CAMP-induced membrane disorder. Rcs transcriptional activation by CAMPs required RcsF and preservation of its two internal disulfide linkages. The rerouting of RcsF to the inner membrane or its synthesis as an unanchored periplasmic protein resulted in constitutive activation of the Rcs regulon and RcsCD-dependent phosphorylation. These findings suggest that RcsFCDB activation in response to CAMP-induced membrane disorder is a result of a change in structure or availability of RcsF to the IM signaling constituents of the Rcs phosphorelay.

APA, Harvard, Vancouver, ISO, and other styles

30

Mizuno, T. "Molecular mechanism underlying His-to-Asp phosphorelay." Seibutsu Butsuri 40, supplement (2000): S111. http://dx.doi.org/10.2142/biophys.40.s111_1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Mizuno, Takeshi. "His-Asp Phosphorelay in Plant Hormone Responses." Journal of Pesticide Science 28, no. 4 (2003): 489–94. http://dx.doi.org/10.1584/jpestics.28.489.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Stephenson, Keith, and James A. Hoch. "Evolution of signalling in the sporulation phosphorelay." Molecular Microbiology 46, no. 2 (2002): 297–304. http://dx.doi.org/10.1046/j.1365-2958.2002.03186.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Egger, Linda A., Heiyoung Park, and Masayori Inouye. "Signal transduction via the histidyl‐aspartyl phosphorelay." Genes to Cells 2, no. 3 (1997): 167–84. http://dx.doi.org/10.1046/j.1365-2443.1997.d01-311.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Hoch, James A., and K. I. Varughese. "Keeping Signals Straight in Phosphorelay Signal Transduction." Journal of Bacteriology 183, no. 17 (2001): 4941–49. http://dx.doi.org/10.1128/jb.183.17.4941-4949.2001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Hoch, James A., and Thomas J. Silhavy. "His–Asp Phosphorelay: Two Components or More?" Cell 85, no. 1 (1996): 13–14. http://dx.doi.org/10.1016/s0092-8674(00)81076-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Perraud, Anne-Laure, Verena Weiss, and Roy Gross. "Signalling pathways in two-component phosphorelay systems." Trends in Microbiology 7, no. 3 (1999): 115–20. http://dx.doi.org/10.1016/s0966-842x(99)01458-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Veening, Jan-Willem, Oscar P. Kuipers, Stanley Brul, Klaas J. Hellingwerf, and Remco Kort. "Effects of Phosphorelay Perturbations on Architecture, Sporulation, and Spore Resistance in Biofilms of Bacillus subtilis." Journal of Bacteriology 188, no. 8 (2006): 3099–109. http://dx.doi.org/10.1128/jb.188.8.3099-3109.2006.

Full text

Abstract:

ABSTRACT The spore-forming bacterium Bacillus subtilis is able to form highly organized multicellular communities called biofilms. This coordinated bacterial behavior is often lost in domesticated or laboratory strains as a result of planktonic growth in rich media for many generations. However, we show here that the laboratory strain B. subtilis 168 is still capable of forming spatially organized multicellular communities on minimal medium agar plates, exemplified by colonies with vein-like structures formed by elevated bundles of cells. In line with the current model for biofilm formation, we demonstrate that overproduction of the phosphorelay components KinA and Spo0A stimulates bundle formation, while overproduction of the transition state regulators AbrB and SinR leads to repression of formation of elevated bundles. Time-lapse fluorescence microscopy studies of B. subtilis green fluorescent protein reporter strains show that bundles are preferential sites for spore formation and that flat structures surrounding the bundles contain vegetative cells. The elevated bundle structures are formed prior to sporulation, in agreement with a genetic developmental program in which these processes are sequentially activated. Perturbations of the phosphorelay by disruption and overexpression of genes that lead to an increased tendency to sporulate result in the segregation of sporulation mutations and decreased heat resistance of spores in biofilms. These results stress the importance of a balanced control of the phosphorelay for biofilm and spore development.

APA, Harvard, Vancouver, ISO, and other styles

38

Singleton, Charles K., Janet H. Kirsten, and Colin J. Dinsmore. "Function of Ammonium Transporter A in the Initiation of Culmination of Development in Dictyostelium discoideum." Eukaryotic Cell 5, no. 7 (2006): 991–96. http://dx.doi.org/10.1128/ec.00058-06.

Full text

Abstract:

ABSTRACT The histidine kinase DhkC controls a phosphorelay involved in regulating the slug versus culmination choice during the multicellular developmental program of Dictyostelium discoideum. When the relay is active, slug migration is favored due to the activation of a cyclic AMP (cAMP) phosphodiesterase and the resultant lowering of the intracellular and extracellular levels of cAMP. Ammonia signaling represents one input into the DhkC phosphorelay, and previous studies indicated that the ammonium transporter C inhibits the relay in response to low ammonia levels. Evidence is presented that another member of the family of ammonium transporters, AmtA, also regulates the slug/culmination choice. Under standard conditions of development, the wild-type strain requires a transitional period of 2 to 3 h to go from fingers to culminants, with some slugs forming and migrating briefly prior to culmination. In contrast, amtA null cells, like cells that lack DhkC, possessed a transitional period of only 1 to 2 h and rarely formed slugs. Disruption of amtA in an amtC null strain overcame the slugger phenotype of that strain and restored its ability to culminate. Strains lacking AmtA were insensitive to the ability of ammonia to promote and prolong slug migration. These findings lead to the proposal that AmtA functions in ammonia sensing as an activator of the DhkC phosphorelay in response to perceived high ammonia levels.

APA, Harvard, Vancouver, ISO, and other styles

39

Hosoya, Shigeo, Kei Asai, Naotake Ogasawara, Michio Takeuchi, and Tsutomu Sato. "Mutation in yaaT Leads to Significant Inhibition of Phosphorelay during Sporulation in Bacillus subtilis." Journal of Bacteriology 184, no. 20 (2002): 5545–53. http://dx.doi.org/10.1128/jb.184.20.5545-5553.2002.

Full text

Abstract:

ABSTRACT In the course of a Bacillus subtilis functional genomics project which involved screening for sporulation genes, we identified an open reading frame, yaaT, whose disruptant exhibits a sporulation defect. Twenty-four hours after the initiation of sporulation, most cells of the yaaT mutant exhibited stage 0 of sporulation, indicating that the yaaT mutation blocks sporulation at an early stage. Furthermore, the mutation in yaaT led to a significant decrease in transcription from a promoter controlled by Spo0A, a key response regulator required for the initiation of sporulation. However, neither the level of transcription of spo0A, the activity of σH, which transcribes spo0A, nor the amount of Spo0A protein was severely affected by the mutation in yaaT. Bypassing the phosphorelay by introducing an spo0A mutation (sof-1) into the yaaT mutant suppressed the sporulation defect, suggesting that the yaaT mutation interferes with the phosphorelay process comprising Spo0F, Spo0B, and histidine kinases. We also observed that mutation of spo0E, which encodes the phosphatase that dephosphorylates Spo0A-P, suppressed the sporulation defect in the yaaT mutant. These results strongly suggest that yaaT plays a significant role in the transduction of signals to the phosphorelay for initiation of sporulation. Micrographs indicated that YaaT-green fluorescent protein localizes to the peripheral membrane, as well as to the septum, during sporulation.

APA, Harvard, Vancouver, ISO, and other styles

40

Mira-Rodado, Virtudes. "New Insights into Multistep-Phosphorelay (MSP)/Two-Component System (TCS) Regulation: Are Plants and Bacteria That Different?" Plants 8, no. 12 (2019): 590. http://dx.doi.org/10.3390/plants8120590.

Full text

Abstract:

The Arabidopsis multistep-phosphorelay (MSP) is a signaling mechanism based on a phosphorelay that involves three different types of proteins: Histidine kinases, phosphotransfer proteins, and response regulators. Its bacterial equivalent, the two-component system (TCS), is the most predominant device for signal transduction in prokaryotes. The TCS has been extensively studied and is thus generally well-understood. In contrast, the MSP in plants was first described in 1993. Although great advances have been made, MSP is far from being completely comprehended. Focusing on the model organism Arabidopsis thaliana, this review summarized recent studies that have revealed many similarities with bacterial TCSs regarding how TCS/MSP signaling is regulated by protein phosphorylation and dephosphorylation, protein degradation, and dimerization. Thus, comparison with better-understood bacterial systems might be relevant for an improved study of the Arabidopsis MSP.

APA, Harvard, Vancouver, ISO, and other styles

41

Bongiorni, Cristina, Ricarda Stoessel, and Marta Perego. "Negative Regulation of Bacillus anthracis Sporulation by the Spo0E Family of Phosphatases." Journal of Bacteriology 189, no. 7 (2007): 2637–45. http://dx.doi.org/10.1128/jb.01798-06.

Full text

Abstract:

ABSTRACT The initiation of sporulation in Bacillus species is controlled by the phosphorelay signal transduction system. Multiple regulatory elements act on the phosphorelay to modulate the level of protein phosphorylation in response to cellular, environmental, and metabolic signals. In Bacillus anthracis nine possible histidine sensor kinases can positively activate the system, while two response regulator aspartyl phosphate phosphatases of the Rap family negatively impact the pathway by dephosphorylating the Spo0F intermediate response regulator. In this study, we have characterized the B. anthracis members of the Spo0E family of phosphatases that specifically dephosphorylate the Spo0A response regulator of the phosphorelay and master regulator of sporulation. The products of four genes were able to promote the dephosphorylation of Spo0A∼P in vitro. The overexpression of two of these B. anthracis Spo0E-like proteins from a multicopy vector consistently resulted in a sporulation-deficient phenotype. A third gene was found to be not transcribed in vivo. A fourth gene encoded a prematurely truncated protein due to a base pair deletion that nevertheless was subject to translational frameshift repair in an Escherichia coli protein expression system. A fifth Spo0E-like protein has been structurally and functionally characterized as a phosphatase of Spo0A∼P by R. N. Grenha et al. (J. Biol. Chem. 281:37993-38003, 2006). We propose that these proteins may contribute to maintain B. anthracis in the transition phase of growth during an active infection and therefore contribute to the virulence of this organism.

APA, Harvard, Vancouver, ISO, and other styles

42

Lee, Myong Gyong, Jae Young Lee, Hyun Kyu Song, and Se Won Suh. "Crystallization and preliminary X-ray analysis of Saccharomyces cerevisiae Ypd1p, a key intermediate in phosphorelay signal transduction." Acta Crystallographica Section D Biological Crystallography 55, no. 6 (1999): 1219–21. http://dx.doi.org/10.1107/s0907444999004059.

Full text

Abstract:

Ypd1p, a 167-residue protein from Saccharomyces cerevisiae, plays a key role in osmosensing phosphorelay signal transduction. It forms part of a multistep phosphorelay system which also includes Sln1p hybrid histidine kinase and two response regulators, Ssk1p and Skn7p. It has been overexpressed in soluble form in Escherichia coli with a His6-tag at its C-terminus. The recombinant protein has been crystallized at room temperature using ammonium sulfate and lithium sulfate as precipitants. Native diffraction data have been collected to 2.3 Å using synchrotron radiation. The crystals are triclinic, belonging to the space group P1, with unit-cell parameters a = 65.78, b = 66.74, c = 65.75 Å, α = 106.60, β = 106.48, γ = 115.53°. The asymmetric unit contains four molecules of the monomeric recombinant Ypd1p, with a corresponding Vm of 2.75 Å3 Da−1 and a solvent content of 55.3%.

APA, Harvard, Vancouver, ISO, and other styles

43

Brunsing, Ryan L., Chandra La Clair, Sharon Tang, et al. "Characterization of Sporulation Histidine Kinases of Bacillus anthracis." Journal of Bacteriology 187, no. 20 (2005): 6972–81. http://dx.doi.org/10.1128/jb.187.20.6972-6981.2005.

Full text

Abstract:

ABSTRACT The initiation of sporulation in Bacillus species is regulated by the phosphorelay signal transduction pathway, which is activated by several histidine sensor kinases in response to cellular and metabolic signals. Comparison of the protein components of the phosphorelay between Bacillus subtilis and Bacillus anthracis revealed high homology in the phosphorelay orthologs of Spo0F, Spo0B, and Spo0A. The sensor domains of sensor histidine kinases are poorly conserved between species, making ortholog recognition tenuous. Putative sporulation sensor histidine kinases of B. anthracis were identified by homology to the HisKA domain of B. subtilis sporulation sensor histidine kinases, which interacts with Spo0F. Nine possible kinases were uncovered, and their genes were assayed for complementation of kinase mutants of B. subtilis, for ability to drive lacZ expression in B. subtilis and B. anthracis, and for the effect of deletion of each on the sporulation of B. anthracis. Five of the nine sensor histidine kinases were inferred to be capable of inducing sporulation in B. anthracis. Four of the sensor kinases could not be shown to induce sporulation; however, the genes for two of these were frameshifted in all B. anthracis strains and one of these was also frameshifted in the pathogenic pXO1-bearing Bacillus cereus strain G9241. It is proposed that acquisition of plasmid pXO1 and pathogenicity may require a dampening of sporulation regulation by mutational selection of sporulation sensor histidine kinase defects. The sporulation of B. anthracis ex vivo appears to result from any one or a combination of the sporulation sensor histidine kinases remaining.

APA, Harvard, Vancouver, ISO, and other styles

44

Martinez-Wilson, Hector F., Rita Tamayo, Anna D. Tischler, David W. Lazinski, and Andrew Camilli. "The Vibrio cholerae Hybrid Sensor Kinase VieS Contributes to Motility and Biofilm Regulation by Altering the Cyclic Diguanylate Level." Journal of Bacteriology 190, no. 19 (2008): 6439–47. http://dx.doi.org/10.1128/jb.00541-08.

Full text

Abstract:

ABSTRACT Phosphorelay systems are important mediators of signal transduction during bacterial adaptation to new environments. Previously we described the vieSAB operon, encoding a putative three-protein component phosphorelay involved in regulating Vibrio cholerae virulence gene expression. At least part of the regulatory activity of VieSAB is exerted through the cyclic diguanylate (c-di-GMP)-degrading activity of the putative response regulator VieA. So far no direct evidence that VieSAB encodes a phosphorelay system exists. In addition, the role VieS plays in modulating VieA activity remains unclear. To address these questions, we expressed and purified VieA and a soluble cytoplasmic portion of VieS and used them in autophosphorylation and phosphotransfer assays. These assays showed that VieS has kinase activity in vitro and is able to selectively phosphorylate VieA. A phenotypic comparison revealed that deletion of vieS results in increased biofilm production comparable to that seen for deletion of vieA, whereas motility was decreased only slightly in the ΔvieS mutant compared to the profound defect observed in a ΔvieA mutant. We also found that the ΔvieS strain has a lower level of vieA transcript and, similar to a ΔvieA mutant, an increased intracellular level of c-di-GMP. Further analysis using site-directed vieA mutants showed that some of the phenotypes observed were due to the phosphorylation status of VieA. The evidence presented in this report is the first to link VieS and VieA biochemically and genetically, lending support to the hypothesis that these proteins function together in a signaling system.

APA, Harvard, Vancouver, ISO, and other styles

45

Laubacher, Mary E., and Sarah E. Ades. "The Rcs Phosphorelay Is a Cell Envelope Stress Response Activated by Peptidoglycan Stress and Contributes to Intrinsic Antibiotic Resistance." Journal of Bacteriology 190, no. 6 (2008): 2065–74. http://dx.doi.org/10.1128/jb.01740-07.

Full text

Abstract:

ABSTRACTGram-negative bacteria possess stress responses to maintain the integrity of the cell envelope. Stress sensors monitor outer membrane permeability, envelope protein folding, and energization of the inner membrane. The systems used by gram-negative bacteria to sense and combat stress resulting from disruption of the peptidoglycan layer are not well characterized. The peptidoglycan layer is a single molecule that completely surrounds the cell and ensures its structural integrity. During cell growth, new peptidoglycan subunits are incorporated into the peptidoglycan layer by a series of enzymes called the penicillin-binding proteins (PBPs). To explore how gram-negative bacteria respond to peptidoglycan stress, global gene expression analysis was used to identifyEscherichia colistress responses activated following inhibition of specific PBPs by the β-lactam antibiotics amdinocillin (mecillinam) and cefsulodin. Inhibition of PBPs with different roles in peptidoglycan synthesis has different consequences for cell morphology and viability, suggesting that not all perturbations to the peptidoglycan layer generate equivalent stresses. We demonstrate that inhibition of different PBPs resulted in both shared and unique stress responses. The regulation of capsular synthesis (Rcs) phosphorelay was activated by inhibition of all PBPs tested. Furthermore, we show that activation of the Rcs phosphorelay increased survival in the presence of these antibiotics, independently of capsule synthesis. Both activation of the phosphorelay and survival required signal transduction via the outer membrane lipoprotein RcsF and the response regulator RcsB. We propose that the Rcs pathway responds to peptidoglycan damage and contributes to the intrinsic resistance ofE. colito β-lactam antibiotics.

APA, Harvard, Vancouver, ISO, and other styles

46

Andresen, Liis, Erki Sala, Viia Kõiv, and Andres Mäe. "A role for the Rcs phosphorelay in regulating expression of plant cell wall degrading enzymes in Pectobacterium carotovorum subsp. carotovorum." Microbiology 156, no. 5 (2010): 1323–34. http://dx.doi.org/10.1099/mic.0.033936-0.

Full text

Abstract:

The Rcs phosphorelay is a signal transduction system that influences the virulence phenotype of several pathogenic bacteria. In the plant pathogen Pectobacterium carotovorum subsp. carotovorum (Pcc) the response regulator of the Rcs phosphorelay, RcsB, represses expression of plant cell wall degrading enzymes (PCWDE) and motility. The focus of this study was to identify genes directly regulated by the binding of RcsB that also regulate expression of PCWDE genes in Pcc. RcsB-binding sites within the regulatory regions of the flhDC operon and the rprA and rsmB genes were identified using DNase I protection assays, while in vivo studies using flhDC : : gusA, rsmB : : gusA and rprA : : gusA gene fusions revealed gene regulation. These experiments demonstrated that the operon flhDC, a flagellar master regulator, was repressed by RcsB, and transcription of rprA was activated by RcsB. Regulation of the rsmB promoter by RcsB is more complicated. Our results show that RcsB represses rsmB expression mainly through modulating flhDC transcription. Neverthless, direct binding of RcsB on the rsmB promoter region is possible in certain conditions. Using an rprA-negative mutant, it was further demonstrated that RprA RNA is not essential for regulating expression of PCWDE under the conditions tested, whereas overexpression of rprA increased protease expression in wild-type cells. Stationary-phase sigma factor, RpoS, is the only known target gene for RprA RNA in Escherichia coli; however, in Pcc the effect of RprA RNA was found to be rpoS-independent. Overall, our results show that the Rcs phosphorelay negatively affects expression of PCWDE by inhibiting expression of flhDC and rsmB.

APA, Harvard, Vancouver, ISO, and other styles

47

Majdalani, Nadim, and Susan Gottesman. "THE RCS PHOSPHORELAY: A Complex Signal Transduction System." Annual Review of Microbiology 59, no. 1 (2005): 379–405. http://dx.doi.org/10.1146/annurev.micro.59.050405.101230.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Sheen, J. "Phosphorelay and Transcription Control in Cytokinin Signal Transduction." Science 296, no. 5573 (2002): 1650–52. http://dx.doi.org/10.1126/science.1071883.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Brown, Jason M., and Richard A. Firtel. "Phosphorelay signalling: New tricks for an ancient pathway." Current Biology 8, no. 18 (1998): R662—R665. http://dx.doi.org/10.1016/s0960-9822(07)00417-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Cotter, Peggy A., and Allison M. Jones. "Phosphorelay control of virulence gene expression in Bordetella." Trends in Microbiology 11, no. 8 (2003): 367–73. http://dx.doi.org/10.1016/s0966-842x(03)00156-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Phosphorelays'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles