scholarly journals Phage-shock-protein (Psp) Envelope Stress Response: Evolutionary History & Discovery of Novel Players

2020 ◽  
Author(s):  
Janani Ravi ◽  
Vivek Anantharaman ◽  
Samuel Zorn Chen ◽  
Pratik Datta ◽  
L Aravind ◽  
...  
Keyword(s):  
Stress Response ◽  
Web Application ◽  
Cell Envelope ◽  
Contextual Information ◽  
Specific Cell ◽  
Bacterial Phyla ◽  
Response System ◽  
Envelope Stress ◽  
Stress Response System ◽  
Conserved Gene

AbstractThe phage shock protein (Psp) stress-response system protects bacteria from envelope stress and stabilizes the cell membrane. Recent work from our group suggests that the psp systems have evolved independently in distinct Gram-positive and Gram-negative bacterial clades to effect similar stress response functions. Despite the prevalence of the key effector, PspA, and the functional Psp system, the various genomic contexts of Psp proteins, as well as their evolution across the kingdoms of life, have not yet been characterized. We have developed a computational pipeline for comparative genomics and protein sequence-structure-function analyses to identify sequence homologs, phyletic patterns, domain architectures, gene neighborhoods, and evolution of the candidates across the tree of life. This integrative pipeline enabled us to make several new discoveries, including the truly universal nature of PspA and the ancestry of the PspA/Snf7 dating all the way back to the Last Universal Common Ancestor. Using contextual information from conserved gene neighborhoods and their domain architectures, we delineated the phyletic patterns of all the Psp members. Next, we systematically identified all possible ‘flavors’ and genomic neighborhoods of the Psp systems. Finally, we traced their evolution, leading us to several interesting findings of their occurrence and co-migration that together point to the functions and roles of Psp in stress-response systems that are often lineage-specific. Conservation of the Psp systems across bacterial phyla emphasizes the established importance of this stress response system in prokaryotes, while the modularity in various lineages is indicative of adaptation to bacteria-specific cell-envelope structures, lifestyles, and adaptation strategies. We also developed an interactive web application that hosts all the data and results in this study that researchers can explore (https://jravilab.shinyapps.io/psp-evolution).

scholarly journals Phyletic distribution and diversification of the Phage Shock Protein stress response system in bacteria and archaea

2021 ◽  
Author(s):  
Philipp F. Popp ◽  
Vadim M. Gumerov ◽  
Ekaterina P. Andrianova ◽  
Lisa Bewersdorf ◽  
Thorsten Mascher ◽  
...  
Keyword(s):  
Stress Response ◽  
Large Scale ◽  
Cell Envelope ◽  
Model Organisms ◽  
Microbial World ◽  
Natural Classification ◽  
Response System ◽  
Core Proteins ◽  
Envelope Stress

AbstractThe bacterial cell envelope is an essential structure that protects the cell from environmental threats, while simultaneously serving as communication interface and diffusion barrier. Therefore, maintaining cell envelope integrity is of vital importance for all microorganisms. Not surprisingly, evolution has shaped conserved protection networks that connect stress perception, transmembrane signal transduction and mediation of cellular responses upon cell envelope stress. The phage shock protein (PSP) stress response is one of such conserved protection networks. Most of the knowledge about the Psp response comes from studies in the Gram-negative model bacterium, Escherichia coli where the Psp system consists of several well-defined protein components. Homologous systems were identified in representatives of Proteobacteria, Actinobacteria, and Firmicutes; however, the Psp system distribution in the microbial world remains largely unknown. By carrying out a large-scale, unbiased comparative genomics analysis, we found components of the Psp system in many bacterial and archaeal phyla and demonstrated that the PSP system deviates dramatically from the proteobacterial prototype. Two of its core proteins, PspA and PspC, have been integrated in various (often phylum-specifically) conserved protein networks during evolution. Based on protein sequence and gene neighborhood analyses of pspA and pspC homologs, we built a natural classification system of PSP networks in bacteria and archaea. We performed a comprehensive in vivo protein interaction screen for the PSP network newly identified in the Gram-positive model organism Bacillus subtilis and found a strong interconnected PSP response system, illustrating the validity of our approach. Our study highlights the diversity of PSP organization and function across many bacterial and archaeal phyla and will serve as foundation for future studies of this envelope stress response beyond model organisms.

scholarly journals Activation of the Cpx-envelope stress response system promotes tolerance to antibacterials delivered by arginine-rich peptides and aminoglycosides in Escherichia coli

2020 ◽  
Author(s):  
Jakob Frimodt-Møller ◽  
Andreas Koulouktsis ◽  
Godefroid Charbon ◽  
Marit Otterlei ◽  
Peter E. Nielsen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stress Response ◽  
Cell Penetrating Peptides ◽  
Resistant Bacteria ◽  
Antimicrobial Compounds ◽  
Inner Membrane ◽  
Response System ◽  
Envelope Stress ◽  
Cell Penetrating ◽  
Stress Response System

AbstractCell penetrating peptides (CPP) are increasingly used for cellular drug delivery in both pro- and eukaryotic cells, and oligoarginines have attracted special attention. However; their mechanism of action, particularly for prokaryotes is still unknown. Arginine-rich CPPs (R-CPP) efficiently delivers the antimicrobial peptide nucleic acid (PNA) into bacteria. Here, we show that resistance to an R-CPP PNA conjugate in Escherichia coli requires multiple genetic modifications and is specific to R-CPP and not to the PNA-part. An integral part of the resistance was the constitutively activated Cpx-envelope stress response system (cpx*), which decreased the cytoplasmic membrane potential and thereby indicates an indirectly energy dependent uptake mechanism. Interestingly, cpx* mutants also showed increased tolerance to aminoglycosides and R-CPP conjugated to a peptide targeting the DNA sliding clamp; i.e., similar uptake in E. coli for these antimicrobial compounds. We speculate that the cpx* phenotype could create an evolutionary opportunity to adapt and evolve in the presence of either compounds.Author summaryThe emergence of multidrug resistant bacteria is raising the need for new classes of antibiotics. Peptide nucleic acids (PNAs) may fill this requirement by their ability to block translation of essential mRNAs and hence inhibit growth. PNA needs conjugation to a delivery peptide (cell penetrating peptide; CPP) to enter the bacteria. Arginine-rich CPPs (CPPR) are receiving a lot of attention for use as delivery vessels. Here, we show, for the first time, CPPR-PNA resistance in Escherichia coli directed towards the delivery peptide. Consequently, resistance also applies to other antimicrobial compounds delivered by the same carrier. An integral part of CPPR resistance is due to a constitutive active Cpx-response system, which leads to a decreased electric potential (ΔΨ) across the inner membrane. The decreased ΔΨ is a result of down-regulation of two aerobic respiratory operons, namely NADH:ubiquinone oxidoreductase complex I and cytochrome bo3 ubiquinol oxidase. The decreased ΔΨ also led to increased tolerance to aminoglycosides. This shows that a (large) negative ΔΨ is important for providing sufficient free energy for membrane translocation of both CPPR and that the inner membrane is the main barrier for entry of both arginine-rich delivery peptides and aminoglycosides.

scholarly journals Identification of Genes in the σ22 Regulon of Pseudomonas aeruginosa Required for Cell Envelope Homeostasis in Either the Planktonic or the Sessile Mode of Growth

mBio ◽  
2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Lynn F. Wood ◽  
Dennis E. Ohman
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Stress Response ◽  
Sigma Factor ◽  
Cell Envelope ◽  
Wall Stress ◽  
Content Type ◽  
Response System ◽  
Cell Wall Stress ◽  
Stress Response System

ABSTRACTThePseudomonas aeruginosaextracytoplasmic functioning (ECF) sigma factor σ22is encoded byalgT/algUand is inhibited by anti-sigma factor MucA. σ22was originally discovered for its essential role in the expression of the exopolysaccharide alginate by mucoid strains associated with chronic pulmonary infection. However, σ22is now known to also have a large regulon associated with the response to cell wall stress. Our recent transcriptome analysis identified 293 open reading frames (ORFs) in the σ22stress stimulon that include genes for outer envelope biogenesis and remodeling, although most of the genes have undefined functions. To better understand the σ22-dependent stress response, mutants affected in 27 genes of the σ22stimulon were examined and expression was studied withlacZfusions. Mutants constructed in the 27 genes showed no major change in response to cell wall-acting antibiotics or growth at elevated temperatures nor in alginate production. The mutants were examined for their effects on the expression of the σ22-dependent promoter of the alginate biosynthetic operon (PalgD) as a measure of σ22derepression from MucA. By testing PalgDexpression under both planktonic and sessile growth conditions, 11 genes were found to play a role in the stress response that activates σ22. Some mutations caused an increase or a decrease in the response to cell wall stress. Interestingly, mutations in 7 of the 11 genes caused constitutive PalgDexpression under nonstressed conditions and thus showed that these genes are involved in maintaining envelope homeostasis. Mutations in PA0062 and PA1324 showed constitutive PalgDexpression during both the planktonic and the sessile modes of growth. However, the PA5178 mutation caused constitutive PalgDexpression only during planktonic growth. In contrast, mutations in PA2717, PA0567, PA3040, and PA0920 caused constitutive PalgDexpression only in the sessile/biofilm mode of growth. This provides evidence that the σ22stimulon for cell envelope homeostasis overlaps with biofilm control mechanisms.IMPORTANCEDuring chronic lung infections, such as in cystic fibrosis patients,Pseudomonas aeruginosaproduces the exopolysaccharide alginate and forms biofilms that shield the organisms from the immune response and increase resistance to antibiotics. Activation of alginate genes is under the control of an extracytoplasmic stress response system that releases an alternative sigma factor (σ22) in response to cell wall stress and then activates expression of a large regulon. In this study, a mutant analysis of 27 members of the regulon showed that 11 play a role in envelope homeostasis and affect the stress response system itself. Interestingly, some genes demonstrate effects only in either the planktonic (free-swimming) or the sessile (biofilm) mode of growth, which leads to persistence and antibiotic tolerance. The studies presented here provide an important initial step in dissecting the mechanisms that regulate a critical signal transduction pathway that impactsP. aeruginosapathogenesis.

scholarly journals The Escherichia coli CpxA-CpxR Envelope Stress Response System Regulates Expression of the Porins OmpF and OmpC

2005 ◽  
Vol 187 (16) ◽  
pp. 5723-5731 ◽  
Author(s):  
Eric Batchelor ◽  
Don Walthers ◽  
Linda J. Kenney ◽  
Mark Goulian
Keyword(s):  
Escherichia Coli ◽  
Stress Response ◽  
Response Regulator ◽  
Gene Encoding ◽  
Fluorescent Reporter ◽  
Response System ◽  
Dnase I Footprinting ◽  
Envelope Stress ◽  
Two Component ◽  
Stress Response System

ABSTRACT We performed transposon mutagenesis of a two-color fluorescent reporter strain to identify new regulators of the porin genes ompF and ompC in Escherichia coli. Screening of colonies by fluorescence microscopy revealed numerous mutants that exhibited interesting patterns of porin expression. One mutant harbored an insertion in the gene encoding the histidine kinase CpxA, the sensor for a two-component signaling system that responds to envelope stress. The cpxA mutant exhibited increased transcription of ompC and a very strong decrease in transcription of ompF under conditions in which acetyl phosphate levels were high. Subsequent genetic analysis revealed that this phenotype is dependent on phosphorylation of the response regulator CpxR and that activation of CpxA in wild-type cells results in similar regulation of porin expression. Using DNase I footprinting, we demonstrated that CpxR binds upstream of both the ompF and ompC promoters. It thus appears that two distinct two-component systems, CpxA-CpxR and EnvZ-OmpR, converge at the porin promoters. Within the context of envelope stress, outer membrane beta-barrel proteins have generally been associated with the sigma E pathway. However, at least for the classical porins OmpF and OmpC, our results show that the Cpx envelope stress response system plays a role in regulating their expression.

The oxidative stress response system

2004 ◽  
pp. 59-76 ◽  
Author(s):  
André Korsloot ◽  
Cornelis A.M. van Gestel ◽  
Nico M. van Straalen
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Oxidative Stress Response ◽  
Response System ◽  
Stress Response System

scholarly journals Genetic analysis of the role of the conserved inner membrane protein CvpA in EHEC resistance to deoxycholate

2020 ◽  
Author(s):  
Alyson R. Warr ◽  
Rachel T. Giorgio ◽  
Matthew K. Waldor
Keyword(s):  
Stress Response ◽  
Membrane Protein ◽  
Bile Salt ◽  
Cell Envelope ◽  
Enteric Bacteria ◽  
Enteric Pathogens ◽  
Inner Membrane ◽  
Bacterial Phyla ◽  
E Coli ◽  
Inner Membrane Protein

The function of cvpA, a bacterial gene predicted to encode an inner membrane protein, is largely unknown. Early studies in E. coli linked cvpA to Colicin V secretion and recent work revealed that it is required for robust intestinal colonization by diverse enteric pathogens. In enterohemorrhagic E. coli (EHEC), cvpA is required for resistance to the bile salt deoxycholate (DOC). Here, we carried out genome-scale transposon-insertion mutagenesis and spontaneous suppressor analysis to uncover cvpA’s genetic interactions and identify common pathways that rescue the sensitivity of a ΔcvpA EHEC mutant to DOC. These screens demonstrated that mutations predicted to activate the σE-mediated extracytoplasmic stress response bypass the ΔcvpA mutant’s susceptibility to DOC. Consistent with this idea, we found that deletions in rseA and msbB and direct overexpression of rpoE restored DOC resistance to the ΔcvpA mutant. Analysis of the distribution of CvpA homologs revealed that this inner membrane protein is conserved across diverse bacterial phyla, in both enteric and non-enteric bacteria that are not exposed to bile. Together, our findings suggest that CvpA plays a role in cell envelope homeostasis in response to DOC and similar stress stimuli in diverse bacterial species. IMPORTANCE Several enteric pathogens, including Enterohemorrhagic E. coli (EHEC), require CvpA to robustly colonize the intestine. This inner membrane protein is also important for secretion of a colicin and EHEC resistance to the bile salt deoxycholate (DOC), but its function is unknown. Genetic analyses carried out here showed that activation of the σE-mediated extracytoplasmic stress response restored the resistance of a cvpA mutant to DOC, suggesting that CvpA plays a role in cell envelope homeostasis. The conservation of CvpA across diverse bacterial phyla suggests that this membrane protein facilitates cell envelope homeostasis in response to varied cell envelope perturbations.

scholarly journals The Rcs System in Enterobacteriaceae: Envelope Stress Responses and Virulence Regulation

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiao Meng ◽  
Glenn Young ◽  
Jingyu Chen
Keyword(s):  
Stress Response ◽  
Stress Responses ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Cell Envelope ◽  
Regulatory System ◽  
Virulence Regulation ◽  
Bacterial Interaction ◽  
Envelope Stress

The bacterial cell envelope is a protective barrier at the frontline of bacterial interaction with the environment, and its integrity is regulated by various stress response systems. The Rcs (regulator of capsule synthesis) system, a non-orthodox two-component regulatory system (TCS) found in many members of the Enterobacteriaceae family, is one of the envelope stress response pathways. The Rcs system can sense envelope damage or defects and regulate the transcriptome to counteract stress, which is particularly important for the survival and virulence of pathogenic bacteria. In this review, we summarize the roles of the Rcs system in envelope stress responses (ESRs) and virulence regulation. We discuss the environmental and intrinsic sources of envelope stress that cause activation of the Rcs system with an emphasis on the role of RcsF in detection of envelope stress and signal transduction. Finally, the different regulation mechanisms governing the Rcs system’s control of virulence in several common pathogens are introduced. This review highlights the important role of the Rcs system in the environmental adaptation of bacteria and provides a theoretical basis for the development of new strategies for control, prevention, and treatment of bacterial infections.

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