scholarly journals A Subfamily of Putative Cytokinin Receptors Is Revealed by an Analysis of the Evolution of the Two-Component Signaling System of Plants

2014 ◽  
Vol 165 (1) ◽  
pp. 227-237 ◽  
Author(s):  
Nijuscha Gruhn ◽  
Mhyeddeen Halawa ◽  
Berend Snel ◽  
Michael F. Seidl ◽  
Alexander Heyl
Keyword(s):  
Signaling System ◽  
Cytokinin Receptors ◽  
Two Component

scholarly journals The EnvZ-OmpR Two-Component Signaling System Is Inactivated in a Mutant Devoid of Osmoregulated Periplasmic Glucans in Dickeya dadantii

2018 ◽  
Vol 9 ◽  
Author(s):  
Marine Caby ◽  
Sébastien Bontemps-Gallo ◽  
Peggy Gruau ◽  
Brigitte Delrue ◽  
Edwige Madec ◽  
...  
Keyword(s):  
Signaling System ◽  
Dickeya Dadantii ◽  
Two Component

scholarly journals Linearmycins Activate a Two-Component Signaling System Involved in Bacterial Competition and Biofilm Morphology

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Reed M. Stubbendieck ◽  
Paul D. Straight
Keyword(s):  
Antibiotic Resistance ◽  
Abc Transporter ◽  
Bacterial Communities ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Bioactive Metabolites ◽  
Signaling System ◽  
Content Type ◽  
Two Component ◽  
Analytical Approaches

ABSTRACT Bacteria use two-component signaling systems to adapt and respond to their competitors and changing environments. For instance, competitor bacteria may produce antibiotics and other bioactive metabolites and sequester nutrients. To survive, some species of bacteria escape competition through antibiotic production, biofilm formation, or motility. Specialized metabolite production and biofilm formation are relatively well understood for bacterial species in isolation. How bacteria control these functions when competitors are present is not well studied. To address fundamental questions relating to the competitive mechanisms of different species, we have developed a model system using two species of soil bacteria, Bacillus subtilis and Streptomyces sp. strain Mg1. Using this model, we previously found that linearmycins produced by Streptomyces sp. strain Mg1 cause lysis of B. subtilis cells and degradation of colony matrix. We identified strains of B. subtilis with mutations in the two-component signaling system yfiJK operon that confer dual phenotypes of specific linearmycin resistance and biofilm morphology. We determined that expression of the ATP-binding cassette (ABC) transporter yfiLMN operon, particularly yfiM and yfiN, is necessary for biofilm morphology. Using transposon mutagenesis, we identified genes that are required for YfiLMN-mediated biofilm morphology, including several chaperones. Using transcriptional fusions, we found that YfiJ signaling is activated by linearmycins and other polyene metabolites. Finally, using a truncated YfiJ, we show that YfiJ requires its transmembrane domain to activate downstream signaling. Taken together, these results suggest coordinated dual antibiotic resistance and biofilm morphology by a single multifunctional ABC transporter promotes competitive fitness of B. subtilis. IMPORTANCE DNA sequencing approaches have revealed hitherto unexplored diversity of bacterial species in a wide variety of environments that includes the gastrointestinal tract of animals and the rhizosphere of plants. Interactions between different species in bacterial communities have impacts on our health and industry. However, many approaches currently used to study whole bacterial communities do not resolve mechanistic details of interspecies interactions, including how bacteria sense and respond to their competitors. Using a competition model, we have uncovered dual functions for a previously uncharacterized two-component signaling system involved in specific antibiotic resistance and biofilm morphology. Insights gleaned from signaling within interspecies interaction models build a more complete understanding of gene functions important for bacterial communities and will enhance community-level analytical approaches.

scholarly journals Novel Role for an HPt Domain in Stabilizing the Phosphorylated State of a Response Regulator Domain

2000 ◽  
Vol 182 (23) ◽  
pp. 6673-6678 ◽  
Author(s):  
Fabiola Janiak-Spens ◽  
David P. Sparling ◽  
Ann H. West
Keyword(s):  
Response Regulator ◽  
Phosphoryl Transfer ◽  
Sensor Kinase ◽  
Signaling System ◽  
Phosphorylated Protein ◽  
Physiological Conditions ◽  
Regulatory Domains ◽  
Regulatory Systems ◽  
Two Component ◽  
Stabilization Effect

ABSTRACT Two-component regulatory systems that utilize a multistep phosphorelay mechanism often involve a histidine-containing phosphotransfer (HPt) domain. These HPt domains serve an essential role as histidine-phosphorylated protein intermediates during phosphoryl transfer from one response regulator domain to another. InSaccharomyces cerevisiae, the YPD1 protein facilitates phosphoryl transfer from a hybrid sensor kinase, SLN1, to two distinct response regulator proteins, SSK1 and SKN7. Because the phosphorylation state largely determines the functional state of response regulator proteins, we have carried out a comparative study of the phosphorylated lifetimes of the three response regulator domains associated with SLN1, SSK1, and SKN7 (R1, R2, and R3, respectively). The isolated regulatory domains exhibited phosphorylated lifetimes within the range previously observed for other response regulator domains (i.e., several minutes to several hours). However, in the presence of YPD1, we found that the half-life of phosphorylated SSK1-R2 was dramatically extended (almost 200-fold longer than in the absence of YPD1). This stabilization effect was specific for SSK1-R2 and was not observed for SLN1-R1 or SKN7-R3. Our findings suggest a mechanism by which SSK1 is maintained in its phosphorylated state under normal physiological conditions and demonstrate an unprecedented regulatory role for an HPt domain in a phosphorelay signaling system.

scholarly journals Feedback control of a two-component signaling system by an Fe-S-binding receiver domain

2019 ◽  
Author(s):  
Benjamin J. Stein ◽  
Aretha Fiebig ◽  
Sean Crosson
Keyword(s):  
Feedback Control ◽  
Histidine Kinase ◽  
Oxygen Sensor ◽  
Cell Physiology ◽  
Environmental Cues ◽  
Sensor Kinase ◽  
Signaling System ◽  
Receiver Domain ◽  
Two Component ◽  
Feedback Inhibitor

AbstractTwo-component signaling systems (TCSs) function to detect environmental cues and transduce this information into a change in transcription. In its simplest form, TCS-dependent regulation of transcription entails phosphoryl-transfer from a sensory histidine kinase to its cognate DNA-binding receiver protein. However, in certain cases, auxiliary proteins may modulate TCSs in response to secondary environmental cues. Caulobacter crescentus FixT is one such auxiliary regulator. FixT is composed of a single receiver domain and functions as a feedback inhibitor of the FixL-FixJ (FixLJ) TCS, which regulates the transcription of genes involved in adaptation to microaerobiosis. We sought to define the impact of fixT on Caulobacter cell physiology and to understand the molecular mechanism by which FixT represses FixLJ signaling. fixT deletion results in excess production of porphyrins and premature entry into stationary phase, demonstrating the importance of feedback inhibition of the FixLJ signaling system. Although FixT is a receiver domain, it does not affect dephosphorylation of the oxygen-sensor kinase FixL or phosphoryltransfer from FixL to its cognate receiver FixJ. Rather, FixT represses FixLJ signaling by inhibiting the FixL autophosphorylation reaction. We have further identified a 4-cysteine motif in Caulobacter FixT that binds an Fe-S cluster and protects the protein from degradation by the Lon protease. Our data support a model in which oxidation of this Fe-S cluster promotes degradation of FixT in vivo. This proteolytic mechanism facilitates clearance the of the FixT feedback inhibitor from the cell under normoxia and resets the FixLJ system for a future microaerobic signaling event.ImportanceTwo-component signal transduction systems (TCSs) are broadly conserved in the bacterial kingdom and generally contain two molecular components: a sensor histidine kinase and a receiver protein. Sensor histidine kinases alter their phosphorylation state in direct response to a physical or chemical cue, whereas receiver proteins “receive” the phosphoryl group from the kinase to regulate a change in cell physiology. We have discovered that a single-domain receiver protein, FixT, binds an Fe-S cluster and controls Caulobacter heme homeostasis though its function as a negative feedback regulator of the oxygen-sensor kinase, FixL. We provide evidence that the Fe-S cluster protects FixT from Lon-dependent proteolysis in the cell and endows FixT with the ability to function as a second, autonomous oxygen/redox sensor in the FixL-FixJ signaling pathway. This study introduces a novel mechanism of regulated TCS feedback control by an Fe-S-binding receiver domain.

scholarly journals Requirement of the CroRS Two-Component System for Resistance to Cell Wall-Targeting Antimicrobials in Enterococcus faecium

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Stephanie L. Kellogg ◽  
Jaime L. Little ◽  
Jessica S. Hoff ◽  
Christopher J. Kristich
Keyword(s):  
Cell Wall ◽  
Enterococcus Faecium ◽  
Wall Stress ◽  
Signaling System ◽  
Beta Lactam ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Cell Wall Stress ◽  
Two Component

ABSTRACT Enterococci are serious opportunistic pathogens that are resistant to many cell wall-targeting antibiotics. The CroRS two-component signaling system responds to antibiotic-mediated cell wall stress and is critical for resistance to cell wall-targeting antibiotics in Enterococcus faecalis. Here, we identify and characterize an orthologous two-component system found in Enterococcus faecium that is functionally equivalent to the CroRS system of E. faecalis. Deletion of croRS in E. faecium resulted in marked susceptibility to cell wall-targeting agents including cephalosporins and bacitracin, as well as moderate susceptibility to ampicillin and vancomycin. As in E. faecalis, exposure to bacitracin and vancomycin stimulates signaling through the CroRS system in E. faecium. Moreover, the CroRS system is critical in E. faecium for enhanced beta-lactam resistance mediated by overexpression of Pbp5. Expression of a Pbp5 variant that confers enhanced beta-lactam resistance cannot overcome the requirement for CroRS function. Thus, the CroRS system is a conserved signaling system that responds to cell wall stress to promote intrinsic resistance to important cell wall-targeting antibiotics in clinically relevant enterococci.

scholarly journals Site-Directed Mutagenesis to Improve Sensitivity of a Synthetic Two-Component Signaling System

PLoS ONE ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. e0147494
Author(s):  
Audrey Olshefsky ◽  
Laila Shehata ◽  
Natalie Kuldell
Keyword(s):  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Signaling System ◽  
Two Component
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