Reduction of cellular stress by TolC-dependent efflux pumps in Escherichia coli indicated by BaeSR and CpxARP activation of spy in efflux mutants.

ABSTRACT: Escherichia coli has nine inner membrane efflux pumps which complex with the outer membrane protein TolC and cognate membrane fusion proteins to form tripartite transperiplasmic pumps with diverse functions, including the expulsion of antibiotics. We recently observed that tolC mutants have elevated activities for three stress response regulators, MarA, SoxS, and Rob, and we suggested that TolC-dependent efflux is required to prevent the accumulation of stressful cellular metabolites. Here, we used spy::lacZ fusions to show that two systems for sensing/repairing extracytoplasmic stress, BaeRS and CpxARP, are activated in the absence of TolC-dependent efflux. In either tolC mutants or bacteria with mutations in the genes for four TolC-dependent efflux pumps, spy expression was increased 6-

SUBMITTER: Rosner JL 

PROVIDER: S-EPMC3571319 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature