scholarly journals Signal Transduction and Regulatory Mechanisms Involved in Control of the σS (RpoS) Subunit of RNA Polymerase

2002 ◽  
Vol 66 (3) ◽  
pp. 373-395 ◽  
Author(s):  
Regine Hengge-Aronis
Keyword(s):  
Rna Polymerase ◽  
Translational Control ◽  
Current Knowledge ◽  
Response Regulator ◽  
Regulatory System ◽  
Stress Conditions ◽  
Acidic Ph ◽  
High Osmolarity ◽  
Multiple Signal ◽  
Rpos Mrna

SUMMARY The σS (RpoS) subunit of RNA polymerase is the master regulator of the general stress response in Escherichia coli and related bacteria. While rapidly growing cells contain very little σS, exposure to many different stress conditions results in rapid and strong σS induction. Consequently, transcription of numerous σS-dependent genes is activated, many of which encode gene products with stress-protective functions. Multiple signal integration in the control of the cellular σS level is achieved by rpoS transcriptional and translational control as well as by regulated σS proteolysis, with various stress conditions differentially affecting these levels of σS control. Thus, a reduced growth rate results in increased rpoS transcription whereas high osmolarity, low temperature, acidic pH, and some late-log-phase signals stimulate the translation of already present rpoS mRNA. In addition, carbon starvation, high osmolarity, acidic pH, and high temperature result in stabilization of σS, which, under nonstress conditions, is degraded with a half-life of one to several minutes. Important cis-regulatory determinants as well as trans-acting regulatory factors involved at all levels of σS regulation have been identified. rpoS translation is controlled by several proteins (Hfq and HU) and small regulatory RNAs that probably affect the secondary structure of rpoS mRNA. For σS proteolysis, the response regulator RssB is essential. RssB is a specific direct σS recognition factor, whose affinity for σS is modulated by phosphorylation of its receiver domain. RssB delivers σS to the ClpXP protease, where σS is unfolded and completely degraded. This review summarizes our current knowledge about the molecular functions and interactions of these components and tries to establish a framework for further research on the mode of multiple signal input into this complex regulatory system.

scholarly journals Insulation of the σF Regulatory System in Bacillus subtilis

2004 ◽  
Vol 186 (13) ◽  
pp. 4390-4394 ◽  
Author(s):  
Karen Carniol ◽  
Tae-Jong Kim ◽  
Chester W. Price ◽  
Richard Losick
Keyword(s):  
Bacillus Subtilis ◽  
Transcription Factors ◽  
Rna Polymerase ◽  
Protein Kinases ◽  
Regulatory System ◽  
Sigma Factors ◽  
Stress Conditions ◽  
Adaptation To Stress ◽  
Regulatory Pathways ◽  
Two Factors

ABSTRACT The transcription factors σF and σB are related RNA polymerase sigma factors that govern dissimilar networks of adaptation to stress conditions in Bacillus subtilis. The two factors are controlled by closely related regulatory pathways, involving protein kinases and phosphatases. We report that insulation of the σF pathway from the σB pathway involves the integrated action of both the cognate kinase and the cognate phosphatase.

scholarly journals Phosphorylation of the Group A Streptococcal CovR Response Regulator Causes Dimerization and Promoter-Specific Recruitment by RNA Polymerase

2006 ◽  
Vol 188 (13) ◽  
pp. 4620-4626 ◽  
Author(s):  
Asiya A. Gusa ◽  
Jinxin Gao ◽  
Virginia Stringer ◽  
Gordon Churchward ◽  
June R. Scott
Keyword(s):  
Rna Polymerase ◽  
Virulence Factors ◽  
Group A Streptococcus ◽  
Response Regulator ◽  
Regulatory System ◽  
In Vitro Transcription ◽  
Wild Type ◽  
Group A ◽  
The Difference

ABSTRACT The group A streptococcus (GAS), Streptococcus pyogenes, is an important human pathogen that causes infections ranging in severity from self-limiting pharyngitis to severe invasive diseases that are associated with significant morbidity and mortality. The pathogenic effects of GAS are mediated by the expression of virulence factors, one of which is the hyaluronic acid capsule (encoded by genes in the has operon). The expression of these virulence factors is controlled by the CovR/S (CsrR/S) two-component regulatory system of GAS which regulates, directly or indirectly, the expression of about 15% of the genome. CovR is a member of the OmpR/PhoB family of transcriptional regulators. Here we show that phosphorylation by acetyl phosphate results in dimerization of CovR. Dimerization was not observed using a D53A mutant of CovR, indicating that D53 is the site of phosphorylation in CovR. Phosphorylation stimulated binding of CovR to a DNA fragment containing the promoter of the has operon (Phas) approximately twofold. Binding of CovR D53A mutant protein to Phas was indistinguishable from the binding of wild-type unphosphorylated CovR. In vitro transcription, using purified GAS RNA polymerase, showed that wild-type CovR repressed transcription, and repression was stimulated more than sixfold by phosphorylation. In the presence of RNA polymerase, binding at Phas of phosphorylated, but not unphosphorylated, CovR was stimulated about fourfold, which accounts for the difference in the effect of phosphorylation on repression versus DNA binding. Thus, regulation of Phas by CovR is direct, and the degree of repression of Phas is controlled by the phosphorylation of CovR.

scholarly journals Activated by Different Signals, the PhoP/PhoQ Two-Component System Differentially Regulates Metal Uptake

2009 ◽  
Vol 191 (23) ◽  
pp. 7174-7181 ◽  
Author(s):  
Eunna Choi ◽  
Eduardo A. Groisman ◽  
Dongwoo Shin
Keyword(s):  
Metal Uptake ◽  
Response Regulator ◽  
Regulatory System ◽  
Acidic Ph ◽  
Transporter Gene ◽  
Coding Region ◽  
Two Component System ◽  
Component System ◽  
Input Signals ◽  
Two Component

ABSTRACT The PhoP/PhoQ two-component system controls several physiological and virulence functions in Salmonella enterica. This system is activated by low Mg2+, acidic pH, and antimicrobial peptides, but the biological consequences resulting from sensing multiple signals are presently unclear. Here, we report that the PhoP/PhoQ system regulates different Salmonella genes depending on whether the inducing signal is acidic pH or low Mg2+. When Salmonella experiences acidic pH, the PhoP/PhoQ system promotes Fe2+ uptake in a process that requires the response regulator RstA, activating transcription of the Fe2+ transporter gene feoB. In contrast, the PhoP-induced RstA protein did not promote feoB expression at neutral pH with low Mg2+. The PhoP/PhoQ system promotes the expression of the Mg2+ transporter mgtA gene only when activated in bacteria starved for Mg2+. This is because mgtA transcription promoted at high Mg2+ concentrations by the acidic-pH-activated PhoP protein failed to reach the mgtA coding region due to the mgtA leader region functioning as a Mg2+ sensor. Our results show that a single two-component regulatory system can regulate distinct sets of genes in response to different input signals.

scholarly journals Evolutionary rewiring: a modified prokaryotic gene-regulatory pathway in chloroplasts

2013 ◽  
Vol 368 (1622) ◽  
pp. 20120260 ◽  
Author(s):  
Sujith Puthiyaveetil ◽  
Iskander M. Ibrahim ◽  
John F. Allen
Keyword(s):  
Green Algae ◽  
Gene Transcription ◽  
Response Regulator ◽  
Regulatory System ◽  
Photosynthetic Electron Transport ◽  
Sensor Kinase ◽  
Ps I ◽  
Component Systems ◽  
Two Component Systems ◽  
Gene Regulatory

Photosynthetic electron transport regulates chloroplast gene transcription through the action of a bacterial-type sensor kinase known as chloroplast sensor kinase (CSK). CSK represses photosystem I (PS I) gene transcription in PS I light and thus initiates photosystem stoichiometry adjustment. In cyanobacteria and in non-green algae, CSK homologues co-exist with their response regulator partners in canonical bacterial two-component systems. In green algae and plants, however, no response regulator partner of CSK is found. Yeast two-hybrid analysis has revealed interaction of CSK with sigma factor 1 (SIG1) of chloroplast RNA polymerase. Here we present further evidence for the interaction between CSK and SIG1. We also show that CSK interacts with quinone. Arabidopsis SIG1 becomes phosphorylated in PS I light, which then specifically represses transcription of PS I genes. In view of the identical signalling properties of CSK and SIG1 and of their interactions, we suggest that CSK is a SIG1 kinase. We propose that the selective repression of PS I genes arises from the operation of a gene-regulatory phosphoswitch in SIG1. The CSK-SIG1 system represents a novel, rewired chloroplast-signalling pathway created by evolutionary tinkering. This regulatory system supports a proposal for the selection pressure behind the evolutionary stasis of chloroplast genes.

scholarly journals Impact of the Resistance Responses to Stress Conditions Encountered in Food and Food Processing Environments on the Virulence and Growth Fitness of Non-Typhoidal Salmonellae

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 617
Author(s):  
Silvia Guillén ◽  
Laura Nadal ◽  
Ignacio Álvarez ◽  
Pilar Mañas ◽  
Guillermo Cebrián
Keyword(s):  
Stress Resistance ◽  
Food Processing ◽  
Current Knowledge ◽  
Foodborne Pathogen ◽  
Stress Conditions ◽  
Bacterial Cells ◽  
Modified Atmospheres ◽  
Development Of Resistance ◽  
Salmonella Virulence ◽  
Short Time

The success of Salmonella as a foodborne pathogen can probably be attributed to two major features: its remarkable genetic diversity and its extraordinary ability to adapt. Salmonella cells can survive in harsh environments, successfully compete for nutrients, and cause disease once inside the host. Furthermore, they are capable of rapidly reprogramming their metabolism, evolving in a short time from a stress-resistance mode to a growth or virulent mode, or even to express stress resistance and virulence factors at the same time if needed, thanks to a complex and fine-tuned regulatory network. It is nevertheless generally acknowledged that the development of stress resistance usually has a fitness cost for bacterial cells and that induction of stress resistance responses to certain agents can trigger changes in Salmonella virulence. In this review, we summarize and discuss current knowledge concerning the effects that the development of resistance responses to stress conditions encountered in food and food processing environments (including acid, osmotic and oxidative stress, starvation, modified atmospheres, detergents and disinfectants, chilling, heat, and non-thermal technologies) exerts on different aspects of the physiology of non-typhoidal Salmonellae, with special emphasis on virulence and growth fitness.

AgmR controls transcription of a regulon with several operons essential for ethanol oxidation in Pseudomonas aeruginosa ATCC 17933

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1851-1857 ◽  
Author(s):  
Nicole Gliese ◽  
Viola Khodaverdi ◽  
Max Schobert ◽  
Helmut Görisch
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ethanol Oxidation ◽  
Response Regulator ◽  
Regulatory System ◽  
Pyrroloquinoline Quinone ◽  
Kanamycin Resistance ◽  
Kanamycin Resistance Cassette ◽  
Two Component ◽  
Ethanol Dehydrogenase ◽  
Oxidation System

The response regulator AgmR was identified to be involved in the regulation of the quinoprotein ethanol oxidation system of Pseudomonas aeruginosa ATCC 17933. Interruption of the agmR gene by insertion of a kanamycin-resistance cassette resulted in mutant NG3, unable to grow on ethanol. After complementation with the intact agmR gene, growth on ethanol was restored. Transcriptional lacZ fusions were used to identify four operons which are regulated by the AgmR protein: the exaA operon encodes the pyrroloquinoline quinone (PQQ)-dependent ethanol dehydrogenase, the exaBC operon encodes a soluble cytochrome c 550 and an aldehyde dehydrogenase, the pqqABCDE operon carries the PQQ biosynthetic genes, and operon exaDE encodes a two-component regulatory system which controls transcription of the exaA operon. Transcription of exaA was restored by transformation of NG3 with a pUCP20T derivative carrying the exaDE genes under lac-promoter control. These data indicate that the AgmR response regulator and the exaDE two-component regulatory system are organized in a hierarchical manner. Gene PA1977, which appears to form an operon with the agmR gene, was found to be non-essential for growth on ethanol.

scholarly journals The Two-Component Regulatory System TCS08 Is Involved in Cellobiose Metabolism of Streptococcus pneumoniae R6

2006 ◽  
Vol 189 (4) ◽  
pp. 1342-1350 ◽  
Author(s):  
Stuart J. McKessar ◽  
Regine Hakenbeck
Keyword(s):  
Streptococcus Pneumoniae ◽  
Response Regulator ◽  
Regulatory System ◽  
Phosphotransferase System ◽  
Two Component System ◽  
Transcription Profiles ◽  
Regulatory Systems ◽  
Two Component ◽  
Cognate Response Regulator ◽  
Gram Positive Cocci

ABSTRACT The two-component system TCS08 is one of the regulatory systems that is important for virulence of Streptococcus pneumoniae. In order to investigate the TCS08 regulon, we have analyzed transcription profiles of mutants derived from S. pneumoniae R6 by microarray analysis. Since deletion mutants are often without a significant phenotype, we constructed a mutation in the histidine kinase HK08, T133P, in analogy to the phosphatase mutation T230P in the H box of the S. pneumoniae CiaH kinase described recently (D. Zähner, K. Kaminski, M. van der Linden, T. Mascher, M. Merai, and R. Hakenbeck, J. Mol. Microbiol. Biotechnol. 4:211-216, 2002). In addition, a deletion mutation was constructed in rr08, encoding the cognate response regulator. The most heavily suppressed genes in the hk08 mutant were spr0276 to spr0282, encoding a putative cellobiose phosphoenolpyruvate sugar phosphotransferase system (PTS). Whereas the R6 Smr parent strain and the Δrr08 mutant readily grew on cellobiose, the hk08 mutant and selected mutants with deletions in the PTS cluster did not, strongly suggesting that TCS08 is involved in the catabolism of cellobiose. Homologues of the TCS08 system were found in closely related streptococci and other gram-positive cocci. However, the genes spr0276 to spr0282, encoding the putative cellobiose PTS, represent a genomic island in S. pneumoniae and homologues were found in Streptococcus gordonii only, suggesting that this system might contribute to the pathogenicity potential of the pneumococcus.

scholarly journals Hanks-Type Serine/Threonine Protein Kinases and Phosphatases in Bacteria: Roles in Signaling and Adaptation to Various Environments

2018 ◽  
Vol 19 (10) ◽  
pp. 2872 ◽  
Author(s):  
Monika Janczarek ◽  
José-María Vinardell ◽  
Paulina Lipa ◽  
Magdalena Karaś
Keyword(s):  
Dna Binding ◽  
Essential Role ◽  
Current Knowledge ◽  
Response Regulator ◽  
Protein Targets ◽  
Regulatory Pathways ◽  
Translational Machinery ◽  
Signaling Systems ◽  
Cellular Processes ◽  
Division Cell

Reversible phosphorylation is a key mechanism that regulates many cellular processes in prokaryotes and eukaryotes. In prokaryotes, signal transduction includes two-component signaling systems, which involve a membrane sensor histidine kinase and a cognate DNA-binding response regulator. Several recent studies indicate that alternative regulatory pathways controlled by Hanks-type serine/threonine kinases (STKs) and serine/threonine phosphatases (STPs) also play an essential role in regulation of many different processes in bacteria, such as growth and cell division, cell wall biosynthesis, sporulation, biofilm formation, stress response, metabolic and developmental processes, as well as interactions (either pathogenic or symbiotic) with higher host organisms. Since these enzymes are not DNA-binding proteins, they exert the regulatory role via post-translational modifications of their protein targets. In this review, we summarize the current knowledge of STKs and STPs, and discuss how these enzymes mediate gene expression in prokaryotes. Many studies indicate that regulatory systems based on Hanks-type STKs and STPs play an essential role in the regulation of various cellular processes, by reversibly phosphorylating many protein targets, among them several regulatory proteins of other signaling cascades. These data show high complexity of bacterial regulatory network, in which the crosstalk between STK/STP signaling enzymes, components of TCSs, and the translational machinery occurs. In this regulation, the STK/STP systems have been proved to play important roles.

scholarly journals Regulation of igaA and the Rcs System by the MviA Response Regulator in Salmonella enterica

2009 ◽  
Vol 191 (8) ◽  
pp. 2743-2752 ◽  
Author(s):  
Clara B. García-Calderón ◽  
Josep Casadesús ◽  
Francisco Ramos-Morales
Keyword(s):  
Membrane Protein ◽  
Salmonella Enterica ◽  
Response Regulator ◽  
Regulatory System ◽  
Enteric Bacteria ◽  
Lon Protease ◽  
Dependent Manner ◽  
Independent Manner ◽  
Serovar Typhimurium

ABSTRACT IgaA is a membrane protein that prevents overactivation of the Rcs regulatory system in enteric bacteria. Here we provide evidence that igaA is the first gene in a σ70-dependent operon of Salmonella enterica serovar Typhimurium that also includes yrfG, yrfH, and yrfI. We also show that the Lon protease and the MviA response regulator participate in regulation of the igaA operon. Our results indicate that MviA regulates igaA transcription in an RpoS-dependent manner, but the results also suggest that MviA may regulate RcsB activation in an RpoS- and IgaA-independent manner.

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.

Sign in / Sign up

Export Citation Format

Share Document