scholarly journals The aminoglycoside resistance-promoting AmgRS envelope stress-responsive two-component system in Pseudomonas aeruginosa is zinc-activated and protects cells from zinc-promoted membrane damage

Microbiology ◽  
2019 ◽  
Vol 165 (5) ◽  
pp. 563-571 ◽  
Author(s):  
Keith Poole ◽  
Thomas Hay ◽  
Christie Gilmour ◽  
Michael Fruci
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Membrane Damage ◽  
Two Component System ◽  
Aminoglycoside Resistance ◽  
Component System ◽  
Envelope Stress ◽  
Two Component

scholarly journals Mutational Activation of the AmgRS Two-Component System in Aminoglycoside-Resistant Pseudomonas aeruginosa

2013 ◽  
Vol 57 (5) ◽  
pp. 2243-2251 ◽  
Author(s):  
Calvin Ho-Fung Lau ◽  
Sebastien Fraud ◽  
Marcus Jones ◽  
Scott N. Peterson ◽  
Keith Poole
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fold Increase ◽  
Wild Type ◽  
Two Component System ◽  
Aminoglycoside Resistance ◽  
Gain Of Function ◽  
Component System ◽  
Content Type ◽  
Resistance Phenotype ◽  
Two Component

ABSTRACTTheamgRSoperon encodes a presumed membrane stress-responsive two-component system linked to intrinsic aminoglycoside resistance inPseudomonas aeruginosa. Genome sequencing of a lab isolate showing modest pan-aminoglycoside resistance, strain K2979, revealed a number of mutations, including a substitution inamgSthat produced an R182C change in the AmgS sensor kinase product of this gene. Introduction of this mutation into an otherwise wild-type strain recapitulated the resistance phenotype, while correcting the mutation in the resistant mutant abrogated the resistant phenotype, confirming that theamgSmutation is responsible for the aminoglycoside resistance of strain K2979. TheamgSR182mutation promoted an AmgR-dependent, 2- to 3-fold increase in expression of the AmgRS target geneshtpXand PA5528, mirroring the impact of aminoglycoside exposure of wild-type cells onhtpXand PA5528 expression. This suggests thatamgSR182is a gain-of-function mutation that activates AmgS and the AmgRS two-component system in promoting modest resistance to aminoglycosides. Screening of several pan-aminoglycoside-resistant clinical isolates ofP. aeruginosarevealed three that showed elevatedhtpXand PA5528 expression and harbored single amino acid-altering mutations inamgS(V121G or D106N) and no mutations inamgR. Introduction of theamgSV121Gmutation into wild-typeP. aeruginosagenerated a resistance phenotype reminiscent of theamgSR182mutant and produced a 2- to 3-fold increase inhtpXand PA5528 expression, confirming that it, too, is a gain-of-function aminoglycoside resistance-promoting mutation. These results highlight the contribution ofamgSmutations and activation of the AmgRS two-component system to acquired aminoglycoside resistance in lab and clinical isolates ofP. aeruginosa.

scholarly journals Potentiation of Aminoglycoside Activity in Pseudomonas aeruginosa by Targeting the AmgRS Envelope Stress-Responsive Two-Component System

2016 ◽  
Vol 60 (6) ◽  
pp. 3509-3518 ◽  
Author(s):  
Keith Poole ◽  
Christie Gilmour ◽  
Maya A. Farha ◽  
Erin Mullen ◽  
Calvin Ho-Fung Lau ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Rna Polymerase ◽  
Multidrug Efflux ◽  
Two Component System ◽  
Component System ◽  
Content Type ◽  
Envelope Stress ◽  
Two Component ◽  
Polymerase Inhibitor ◽  
Multidrug Efflux System

A screen for agents that potentiated the activity of paromomycin (PAR), a 4,5-linked aminoglycoside (AG), against wild-typePseudomonas aeruginosaidentified the RNA polymerase inhibitor rifampin (RIF). RIF potentiated additional 4,5-linked AGs, such as neomycin and ribostamycin, but not the clinically important 4,6-linked AGs amikacin and gentamicin. Potentiation was absent in a mutant lacking the AmgRS envelope stress response two-component system (TCS), which protects the organism from AG-generated membrane-damaging aberrant polypeptides and, thus, promotes AG resistance, an indication that RIF was acting via this TCS in potentiating 4,5-linked AG activity. Potentiation was also absent in a RIF-resistant RNA polymerase mutant, consistent with its potentiation of AG activity being dependent on RNA polymerase perturbation. PAR-inducible expression of the AmgRS-dependent geneshtpXandyccAwas reduced by RIF, suggesting that AG activation of this TCS was compromised by this agent. Still, RIF did not compromise the membrane-protective activity of AmgRS, an indication that it impacted some other function of this TCS. RIF potentiated the activities of 4,5-linked AGs against several AG-resistant clinical isolates, in two cases also potentiating the activity of the 4,6-linked AGs. These cases were, in one instance, explained by an observed AmgRS-dependent expression of the MexXY multidrug efflux system, which accommodates a range of AGs, with RIF targeting of AmgRS underminingmexXYexpression and its promotion of resistance to 4,5- and 4,6-linked AGs. Given this link between AmgRS, MexXY expression, and pan-AG resistance inP. aeruginosa, RIF might be a useful adjuvant in the AG treatment ofP. aeruginosainfections.

scholarly journals The two-component system CopRS maintains femtomolar levels of free copper in the periplasm of Pseudomonas aeruginosa using a phosphatase-based mechanism

2020 ◽  
Author(s):  
Lorena Novoa-Aponte ◽  
Fernando C. Soncini ◽  
José M. Argüello
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phosphatase Activity ◽  
Response Regulator ◽  
Redox Enzymes ◽  
Two Component System ◽  
Component System ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems ◽  
Systems Control

ABSTRACTTwo component systems control periplasmic Cu+ homeostasis in Gram-negative bacteria. In characterized systems such as Escherichia coli CusRS, upon Cu+ binding to the periplasmic sensing domain of CusS, a cytoplasmic phosphotransfer domain phosphorylates the response regulator CusR. This drives the expression of efflux transporters, chaperones, and redox enzymes to ameliorate metal toxic effects. Here, we show that the Pseudomonas aeruginosa two component sensor histidine kinase CopS exhibits a Cu-dependent phosphatase activity that maintains a non-phosphorylated CopR when the periplasmic Cu levels are below its activation threshold. Upon Cu+ binding to the sensor, the phosphatase activity is blocked and the phosphorylated CopR activates transcription of the CopRS regulon. Supporting the model, mutagenesis experiments revealed that the ΔcopS strain showed constitutive high expression of the CopRS regulon, lower intracellular Cu+ levels, and larger Cu tolerance when compared to wild type cells. The invariant phospho-acceptor residue His235 of CopS was not required for the phosphatase activity itself, but necessary for its Cu-dependency. To sense the metal, the periplasmic domain of CopS binds two Cu+ ions at its dimeric interface. Homology modeling of CopS based on CusS structure (four Ag+ binding sites) clearly explains the different binding stoichiometries in both systems. Interestingly, CopS binds Cu+/2+ with 30 × 10−15 M affinities, pointing to the absence of free (hydrated) Cu+/2+ in the periplasm.IMPORTANCECopper is a micronutrient required as cofactor in redox enzymes. When free, copper is toxic, mismetallating proteins, and generating damaging free radicals. Consequently, copper overload is a strategy that eukaryotic cells use to combat pathogens. Bacteria have developed copper sensing transcription factors to control copper homeostasis. The cell envelope is the first compartment that has to cope with copper stress. Dedicated two component systems control the periplasmic response to metal overload. This manuscript shows that the copper sensing two component system present in Pseudomonadales exhibits a signal-dependent phosphatase activity controlling the activation of the response regulator, distinct from previously described periplasmic Cu sensors. Importantly, the data show that the sensor is activated by copper levels compatible with the absence of free copper in the cell periplasm. This emphasizes the diversity of molecular mechanisms that have evolved in various bacteria to manage the copper cellular distribution.

scholarly journals Two-Component System Cross-Regulation Integrates Bacillus anthracis Response to Heme and Cell Envelope Stress

2014 ◽  
Vol 10 (3) ◽  
pp. e1004044 ◽  
Author(s):  
Laura A. Mike ◽  
Jacob E. Choby ◽  
Paul R. Brinkman ◽  
Lorenzo Q. Olive ◽  
Brendan F. Dutter ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Cell Envelope ◽  
Two Component System ◽  
Component System ◽  
Envelope Stress ◽  
Two Component

The PprA-PprB two-component system activates CupE, the first non-archetypal Pseudomonas aeruginosa chaperone-usher pathway system assembling fimbriae

2010 ◽  
Vol 13 (3) ◽  
pp. 666-683 ◽  
Author(s):  
Caroline Giraud ◽  
Christophe S. Bernard ◽  
Virginie Calderon ◽  
Liang Yang ◽  
Alain Filloux ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Two Component System ◽  
Component System ◽  
Two Component
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