Characterization of the Induction and Cellular Role of the BaeSR Two-Component Envelope Stress Response of Escherichia coli
- 1 July 2011
- journal article
- research article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 193 (13), 3367-3375
- https://doi.org/10.1128/jb.01534-10
Abstract
The bacterial cell envelope is the interface between a bacterium and its environment and is constantly exposed to environmental changes. The BaeSR two-component system regulates one of six envelope stress responses in Escherichia coli and is induced by spheroplasting, overexpression of the pilin subunit PapG, and exposure to indole. The known BaeR regulon is small, consisting of eight genes, mdtABCD-baeSR , acrD , and spy , two of which encode the BaeSR two-component system itself. In this study, we investigated the molecular nature of the BaeS-inducing cue and the cellular role of the BaeSR envelope stress response. We demonstrated that at least two flavonoids and sodium tungstate are novel inducers of the BaeSR response. Interestingly, flavonoids and sodium tungstate led to much stronger induction of the BaeSR response in an mdtA efflux pump mutant, while indole did not. These findings are consistent with the hypothesis that flavonoids and sodium tungstate are natural substrates of the MdtABC efflux pump. Indole has recently been implicated in cell-cell signaling and biofilm repression through a putative interaction with the LuxR homologue SdiA. Using genetic analyses, we found that induction of the BaeSR response by indole occurs via a pathway separate from the SdiA biofilm pathway. Further, we demonstrated that the BaeSR response does not influence biofilm formation, nor is it involved in indole-mediated inhibition of biofilm formation. We hypothesize that the main function of the Bae response is to upregulate efflux pump expression in response to specific envelope-damaging agents.Keywords
This publication has 45 references indexed in Scilit:
- Reconfiguring the Quorum-Sensing Regulator SdiA ofEscherichia coliTo Control Biofilm Formation via Indole andN-Acylhomoserine LactonesApplied and Environmental Microbiology, 2009
- The Rcs Phosphorelay Is a Cell Envelope Stress Response Activated by Peptidoglycan Stress and Contributes to Intrinsic Antibiotic ResistanceJournal of Bacteriology, 2008
- The BaeSR Two-Component Regulatory System Mediates Resistance to Condensed Tannins in Escherichia coliApplied and Environmental Microbiology, 2008
- Regulation of Multidrug Efflux Systems Involved in Multidrug and Metal Resistance of Salmonella enterica Serovar TyphimuriumJournal of Bacteriology, 2007
- EnterohemorrhagicEscherichia coliBiofilms Are Inhibited by 7-Hydroxyindole and Stimulated by IsatinApplied and Environmental Microbiology, 2007
- YcfR (BhsA) InfluencesEscherichia coliBiofilm Formation through Stress Response and Surface HydrophobicityJournal of Bacteriology, 2007
- Release of outer membrane vesicles by Gram‐negative bacteria is a novel envelope stress responseMolecular Microbiology, 2006
- Outer Membrane Vesicle Production byEscherichia coliIs Independent of Membrane InstabilityJournal of Bacteriology, 2006
- YliH (BssR) and YceP (BssS) Regulate Escherichia coli K-12 Biofilm Formation by Influencing Cell SignalingApplied and Environmental Microbiology, 2006
- Construction of Escherichia coli K‐12 in‐frame, single‐gene knockout mutants: the Keio collectionMolecular Systems Biology, 2006