scholarly journals A Novel Two-Component System, GluR-GluK, Involved in Glutamate Sensing and Uptake in Streptomyces coelicolor

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Lei Li ◽  
Weihong Jiang ◽  
Yinhua Lu
Keyword(s):  
Signal Transduction ◽  
Glutamate Uptake ◽  
Streptomyces Coelicolor ◽  
Signal Transduction Pathway ◽  
Antibiotic Biosynthesis ◽  
Transduction Pathway ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component

ABSTRACT Two-component systems (TCSs), the predominant signal transduction pathways employed by bacteria, play important roles in physiological metabolism in Streptomyces. Here, a novel TCS, GluR-GluK (encoded by SCO5778-SCO5779), which is located divergently from the gluABCD operon encoding a glutamate uptake system, was identified as being involved in glutamate sensing and uptake as well as antibiotic biosynthesis in Streptomyces coelicolor. Under the condition of minimal medium (MM) supplemented with different concentrations of glutamate, deletion of the gluR-gluK operon (gluR-K) resulted in enhanced actinorhodin (ACT) but reduced undecylprodigiosin (RED) and yellow type I polyketide (yCPK) production, suggesting that GluR-GluK plays a differential role in antibiotic biosynthesis. Furthermore, we found that the response regulator GluR directly promotes the expression of gluABCD under the culture condition of MM with a high concentration of glutamate (75 mM). Using the biolayer interferometry assay, we demonstrated that glutamate acts as the direct signal of the histidine kinase GluK. It was therefore suggested that upon sensing high concentrations of glutamate, GluR-GluK would be activated and thereby facilitate glutamate uptake by increasing gluABCD expression. Finally, we demonstrated that the role of GluR-GluK in antibiotic biosynthesis is independent of its function in glutamate uptake. Considering the wide distribution of the glutamate-sensing (GluR-GluK) and uptake (GluABCD) module in actinobacteria, it could be concluded that the GluR-GluK signal transduction pathway involved in secondary metabolism and glutamate uptake should be highly conserved in this bacterial phylum. IMPORTANCE In this study, a novel two-component system (TCS), GluR-GluK, was identified to be involved in glutamate sensing and uptake as well as antibiotic biosynthesis in Streptomyces coelicolor. A possible GluR-GluK working model was proposed. Upon sensing high glutamate concentrations (such as 75 mM), activated GluR-GluK could regulate both glutamate uptake and antibiotic biosynthesis. However, under a culture condition of MM supplemented with low concentrations of glutamate (such as 10 mM), although GluR-GluK is activated, its activity is sufficient only for the regulation of antibiotic biosynthesis. To the best of our knowledge, this is the first report describing a TCS signal transduction pathway for glutamate sensing and uptake in actinobacteria.

scholarly journals CrdS and CrdA Comprise a Two-Component System That Is Cooperatively Regulated by the Che3 Chemosensory System in Myxococcus xanthus

mBio ◽  
2011 ◽  
Vol 2 (4) ◽  
Author(s):  
Jonathan W. Willett ◽  
John R. Kirby
Keyword(s):  
Signal Transduction ◽  
Myxococcus Xanthus ◽  
Complex Signal ◽  
Central Processor ◽  
Two Component System ◽  
Component System ◽  
Chemosensory System ◽  
Content Type ◽  
Phosphorylation State ◽  
Two Component

ABSTRACTMyxococcus xanthusserves as a model organism for development and complex signal transduction. Regulation of developmental aggregation and sporulation is controlled, in part, by the Che3 chemosensory system. The Che3 pathway consists of homologs to two methyl-accepting chemotaxis proteins (MCPs), CheA, CheW, CheB, and CheR but not CheY. Instead, the output for Che3 is the NtrC homolog CrdA, which functions to regulate developmental gene expression. In this paper we have identified an additional kinase, CrdS, which directly regulates the phosphorylation state of CrdA. Both epistasis andin vitrophosphotransfer assays indicate that CrdS functions as part of the Che3 pathway and, in addition to CheA3, serves to regulate CrdA phosphorylation inM. xanthus. We provide kinetic data for CrdS autophosphorylation and demonstrate specificity for phosphotransfer from CrdS to CrdA. We further demonstrate that CheA3 destabilizes phosphorylated CrdA (CrdA~P), indicating that CheA3 likely acts as a phosphatase. Both CrdS and CheA3 control developmental progression by regulating the phosphorylation state of CrdA~P in the cell. These results support a model in which a classical two-component system and a chemosensory system act synergistically to control the activity of the response regulator CrdA.IMPORTANCEWhile phosphorylation-mediated signal transduction is well understood in prototypical chemotaxis and two-component systems (TCS), chemosensory regulation of alternative cellular functions (ACF) has not been clearly defined. The Che3 system inMyxococcus xanthusis a member of the ACF class of chemosensory systems and regulates development via the transcription factor CrdA (chemosensoryregulator ofdevelopment) (K. Wuichet and I. B. Zhulin, Sci. Signal. 3:ra50, 2010; J. R. Kirby and D. R. Zusman, Proc. Natl. Acad. Sci. U. S. A. 100:2008–2013, 2003). We have identified and characterized a homolog of NtrB, designated CrdS, capable of specifically phosphorylating the NtrC homolog CrdA inM. xanthus. Additionally, we demonstrate that the CrdSA two-component system is negatively regulated by CheA3, the central processor within the Che3 system ofM. xanthus. To our knowledge, this study provides the first example of an ACF chemosensory system regulating a prototypical two-component system and extends our understanding of complex regulation of developmental signaling pathways.

scholarly journals Regulation of the Streptomyces coelicolor Calcium-Dependent Antibiotic by absA, Encoding a Cluster-Linked Two-Component System

2002 ◽  
Vol 184 (3) ◽  
pp. 794-805 ◽  
Author(s):  
N. Jamie Ryding ◽  
Todd B. Anderson ◽  
Wendy C. Champness
Keyword(s):  
Genomic Sequence ◽  
Sequence Data ◽  
Streptomyces Coelicolor ◽  
Negative Regulation ◽  
Negative Regulator ◽  
Antibiotic Biosynthesis ◽  
Two Component System ◽  
Component System ◽  
Calcium Dependent ◽  
Two Component

ABSTRACT The Streptomyces coelicolor absA two-component system was initially identified through analysis of mutations in the sensor kinase absA1 that caused inhibition of all four antibiotics synthesized by this strain. Previous genetic analysis had suggested that the phosphorylated form of AbsA2 acted as a negative regulator of antibiotic biosynthesis in S. coelicolor (T. B. Anderson, P. Brian, and W. C. Champness, Mol. Microbiol. 39:553–566, 2001). Genomic sequence data subsequently provided by the Sanger Centre (Cambridge, United Kingdom) revealed that absA was located within the gene cluster for production of one of the four antibiotics, calcium-dependent antibiotic (CDA). In this paper we have identified numerous transcriptional start sites within the CDA cluster and have shown that the original antibiotic-negative mutants used to identify absA exhibit a stronger negative regulation of promoters upstream of the proposed CDA biosynthetic genes than of promoters in the clusters responsible for production of actinorhodin and undecylprodigiosin. The same antibiotic-negative mutants also showed an increase in transcription from a promoter divergent to that of absA, upstream of a putative ABC transporter, in addition to an increase in transcription of absA itself. Interestingly, the negative regulation of the biosynthetic transcripts did not appear to be mediated by transcriptional regulation of cdaR (a gene encoding a homolog of the pathway-specific regulators of the act and red clusters) or by any other recognizable transcriptional regulator associated with the cluster. The role of absA in regulating the expression of the diverse antibiotic biosynthesis clusters in the genome is discussed in light of its location in the cda cluster.

scholarly journals Conformational Changes of an Interdomain Linker Mediate Mechanical Signal Transmission in Sensor Kinase BvgS

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Elodie Lesne ◽  
Elian Dupré ◽  
Camille Locht ◽  
Rudy Antoine ◽  
Françoise Jacob-Dubuisson
Keyword(s):  
Signal Transduction ◽  
Bordetella Pertussis ◽  
Coiled Coil ◽  
Protein Domain ◽  
Sensor Kinase ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Sensor Kinases

ABSTRACT The whooping cough agent, Bordetella pertussis, controls the expression of its large virulence regulon in a coordinated manner through the two-component system BvgAS. BvgS is a dimeric, multidomain sensor kinase. Each monomer comprises, in succession, tandem periplasmic Venus flytrap (VFT) domains, a transmembrane segment, a cytoplasmic Per-Arnt-Sim (PAS) domain, a kinase module, and additional phosphorelay domains. BvgS shifts between kinase and phosphatase modes of activity in response to chemical modulators that modify the clamshell motions of the VFT domains. We have shown previously that this regulation involves a shift between distinct states of conformation and dynamics of the two-helix coiled-coil linker preceding the enzymatic module. In this work, we determined the mechanism of signal transduction across the membrane via a first linker, which connects the VFT and PAS domains of BvgS, using extensive cysteine cross-linking analyses and other approaches. Modulator perception by the periplasmic domains appears to trigger a small, symmetrical motion of the transmembrane segments toward the periplasm, causing rearrangements of the noncanonical cytoplasmic coiled coil that follows. As a consequence, the interface of the PAS domains is modified, which affects the second linker and eventually causes the shift of enzymatic activity. The major features of this first linker are well conserved among BvgS homologs, indicating that the mechanism of signal transduction unveiled here is likely to be generally relevant for this family of sensor kinases. IMPORTANCE Bordetella pertussis produces virulence factors coordinately regulated by the two-component system BvgAS. BvgS is a sensor kinase, and BvgA is a response regulator that activates gene transcription when phosphorylated by BvgS. Sensor kinases homologous to BvgS are also found in other pathogens. Our goal is to decipher the mechanisms of BvgS signaling, since these sensor kinases may represent new targets for antibacterial agents. Signal perception by the sensor domains of BvgS triggers small motions of the helical linker region underneath. The protein domain that follows this linker undergoes a large conformational change that amplifies the initial signal, causing a shift of activity from kinase to phosphatase. Because BvgS homologs harbor similar regions, these signaling mechanisms are likely to apply generally to that family of sensor kinases.

scholarly journals Nutritional Regulation of the Sae Two-Component System by CodY inStaphylococcus aureus

2018 ◽  
Vol 200 (8) ◽  
Author(s):  
Kevin D. Mlynek ◽  
William E. Sause ◽  
Derek E. Moormeier ◽  
Marat R. Sadykov ◽  
Kurt R. Hill ◽  
...  
Keyword(s):  
Gene Expression ◽  
Virulence Factors ◽  
Virulence Gene ◽  
Nutrient Depletion ◽  
Global Regulator ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Two Component

ABSTRACTStaphylococcus aureussubverts innate defenses during infection in part by killing host immune cells to exacerbate disease. This human pathogen intercepts host cues and activates a transcriptional response via theS. aureusexoprotein expression (SaeR/SaeS [SaeR/S]) two-component system to secrete virulence factors critical for pathogenesis. We recently showed that the transcriptional repressor CodY adjusts nuclease (nuc) gene expression via SaeR/S, but the mechanism remained unknown. Here, we identified two CodY binding motifs upstream of thesaeP1 promoter, which suggested direct regulation by this global regulator. We show that CodY shares a binding site with the positive activator SaeR and that alleviating direct CodY repression at this site is sufficient to abrogate stochastic expression, suggesting that CodY repressessaeexpression by blocking SaeR binding. Epistasis experiments support a model that CodY also controlssaeindirectly through Agr and Rot-mediated repression of thesaeP1 promoter. We also demonstrate that CodY repression ofsaerestrains production of secreted cytotoxins that kill human neutrophils. We conclude that CodY plays a previously unrecognized role in controlling virulence gene expression via SaeR/S and suggest a mechanism by which CodY acts as a master regulator of pathogenesis by tying nutrient availability to virulence gene expression.IMPORTANCEBacterial mechanisms that mediate the switch from a commensal to pathogenic lifestyle are among the biggest unanswered questions in infectious disease research. Since the expression of most virulence genes is often correlated with nutrient depletion, this implies that virulence is a response to the lack of nourishment in host tissues and that pathogens likeS. aureusproduce virulence factors in order to gain access to nutrients in the host. Here, we show that specific nutrient depletion signals appear to be funneled to the SaeR/S system through the global regulator CodY. Our findings reveal a strategy by whichS. aureusdelays the production of immune evasion and immune-cell-killing proteins until key nutrients are depleted.

scholarly journals The Staphylococcus aureus KdpDE Two-Component System Couples Extracellular K+Sensing and Agr Signaling to Infection Programming

2011 ◽  
Vol 79 (6) ◽  
pp. 2154-2167 ◽  
Author(s):  
Ting Xue ◽  
Yibo You ◽  
De Hong ◽  
Haipeng Sun ◽  
Baolin Sun
Keyword(s):  
Staphylococcus Aureus ◽  
Uptake System ◽  
Main Function ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Virulence Regulator ◽  
External K

ABSTRACTThe Kdp system is widely distributed among bacteria. InEscherichia coli, the Kdp-ATPase is a high-affinity K+uptake system and its expression is activated by the KdpDE two-component system in response to K+limitation or salt stress. However, information about the role of this system in many bacteria still remains obscure. Here we demonstrate that KdpFABC inStaphylococcus aureusis not a major K+transporter and that the main function of KdpDE is not associated with K+transport but that instead it regulates transcription for a series of virulence factors through sensing external K+concentrations, indicating that this bacterium might modulate its infectious status through sensing specific external K+stimuli in different environments. Our results further reveal thatS. aureusKdpDE is upregulated by the Agr/RNAIII system, which suggests that KdpDE may be an important virulence regulator coordinating the external K+sensing and Agr signaling during pathogenesis in this bacterium.

scholarly journals The CasKR Two-Component System Is Required for the Growth of Mesophilic and Psychrotolerant Bacillus cereus Strains at Low Temperatures

2014 ◽  
Vol 80 (8) ◽  
pp. 2493-2503 ◽  
Author(s):  
Sara Esther Diomandé ◽  
Stéphanie Chamot ◽  
Vera Antolinos ◽  
Florian Vasai ◽  
Marie-Hélène Guinebretière ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Two Component System ◽  
Diverse Range ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Temperature Ranges ◽  
Different Strains

ABSTRACTThe different strains ofBacillus cereuscan grow at temperatures covering a very diverse range. SomeB. cereusstrains can grow in chilled food and consequently cause food poisoning. We have identified a new sensor/regulator mechanism involved in low-temperatureB. cereusgrowth. Construction of a mutant of this two-component system enabled us to show that this system, called CasKR, is required for growth at the minimal temperature (Tmin). CasKR was also involved in optimal cold growth aboveTminand in cell survival belowTmin. Microscopic observation showed that CasKR plays a key role in cell shape during cold growth. Introducing thecasKRgenes in a ΔcasKRmutant restored its ability to grow atTmin. Although it was first identified in the ATCC 14579 model strain, this mechanism has been conserved in most strains of theB. cereusgroup. We show that the role of CasKR in cold growth is similar in otherB. cereus sensu latostrains with different growth temperature ranges, including psychrotolerant strains.

scholarly journals Identification of a Second Two-Component Signal Transduction System That Controls Fosfomycin Tolerance and Glycerol-3-Phosphate Uptake

2014 ◽  
Vol 197 (5) ◽  
pp. 861-871 ◽  
Author(s):  
Kumiko Kurabayashi ◽  
Yuko Hirakawa ◽  
Koichi Tanimoto ◽  
Haruyoshi Tomita ◽  
Hidetada Hirakawa
Keyword(s):  
Phosphate Uptake ◽  
Response Regulator ◽  
Anaerobic Respiration ◽  
Regulatory System ◽  
Carbon Substrate ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Biological Cost

Particular interest in fosfomycin has resurfaced because it is a highly beneficial antibiotic for the treatment of refractory infectious diseases caused by pathogens that are resistant to other commonly used antibiotics. The biological cost to cells of resistance to fosfomycin because of chromosomal mutation is high. We previously found that a bacterial two-component system, CpxAR, induces fosfomycin tolerance in enterohemorrhagicEscherichia coli(EHEC) O157:H7. This mechanism does not rely on irreversible genetic modification and allows EHEC to relieve the fitness burden that results from fosfomycin resistance in the absence of fosfomycin. Here we show that another two-component system, TorSRT, which was originally characterized as a regulatory system for anaerobic respiration utilizing trimethylamine-N-oxide (TMAO), also induces fosfomycin tolerance. Activation of the Tor regulatory pathway by overexpression oftorR, which encodes the response regulator, or addition of TMAO increased fosfomycin tolerance in EHEC. We also show that phosphorylated TorR directly represses the expression ofglpT, a gene that encodes a symporter of fosfomycin and glycerol-3-phosphate, and activation of the TorR protein results in the reduced uptake of fosfomycin by cells. However, cells in which the Tor pathway was activated had an impaired growth phenotype when cultured with glycerol-3-phosphate as a carbon substrate. These observations suggest that the TorSRT pathway is the second two-component system to reversibly control fosfomycin tolerance and glycerol-3-phosphate uptake in EHEC, and this may be beneficial for bacteria by alleviating the biological cost. We expect that this mechanism could be a potential target to enhance the utility of fosfomycin as chemotherapy against multidrug-resistant pathogens.

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