Dataset Information

Members of the conserved DedA family are likely membrane transporters and are required for drug resistance in Escherichia coli.

ABSTRACT: Bacterial resistance to antibiotics and biocides is an increasing public health problem. Genes encoding integral membrane proteins belonging to the DedA family are present in most bacterial genomes, including Escherichia coli. An E. coli strain lacking partially redundant DedA family genes yqjA and yghB (strain BC202) displays temperature sensitivity and cell division defects. These phenotypes can be corrected by overexpression of mdfA, an Na(+)-K(+)/H(+) antiporter of the major facilitator superfamily. We show that BC202 is hypersensitive to several biocides and cationic compounds that are known substrates of several multidrug resistance transporters, including MdfA, EmrE, and AcrB. The introduction of deletions of genes encoding these drug transporters into BC202 results in additional sensitivity. Expression of wild-type yghB or yqjA can restore drug resistance, but this is eliminated upon mutation of two membrane-embedded acidic amino acids (E39 or D51 in either protein). This dependence upon membrane-embedded acidic amino acids is a hallmark of proton-dependent antiporters. Overexpression of mdfA in BC202 or artificially restoring proton motive force (PMF) restores wild-type resistance to substrates of MdfA as well as other drug resistance transporters such as EmrE and AcrAB. These results suggest that YqjA and YghB may be membrane transporters required for PMF-dependent drug efflux in E. coli.

SUBMITTER: Kumar S

PROVIDER: S-EPMC3910893 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Members of the conserved DedA family are likely membrane transporters and are required for drug resistance in Escherichia coli.

Kumar Sujeet S Doerrler William T WT

Antimicrobial agents and chemotherapy 20131125 2

Bacterial resistance to antibiotics and biocides is an increasing public health problem. Genes encoding integral membrane proteins belonging to the DedA family are present in most bacterial genomes, including Escherichia coli. An E. coli strain lacking partially redundant DedA family genes yqjA and yghB (strain BC202) displays temperature sensitivity and cell division defects. These phenotypes can be corrected by overexpression of mdfA, an Na(+)-K(+)/H(+) antiporter of the major facilitator supe ...[more]

PMID: 24277026

Similar Datasets

Project description:UnlabelledThe ability to persist and grow under alkaline conditions is an important characteristic of many bacteria. In order to survive at alkaline pH, Escherichia coli must maintain a stable cytoplasmic pH of about 7.6. Membrane cation/proton antiporters play a major role in alkaline pH homeostasis by catalyzing active inward proton transport. The DedA/Tvp38 family is a highly conserved membrane protein family of unknown function present in most sequenced genomes. YqjA and YghB are members of the E. coli DedA family with 62% amino acid identity and partially redundant functions. We have shown that E. coli with ΔyqjA and ΔyghB mutations cannot properly maintain the proton motive force (PMF) and is compromised in PMF-dependent drug efflux and other PMF-dependent functions. Furthermore, the functions of YqjA and YghB are dependent upon membrane-embedded acidic amino acids, a hallmark of several families of proton-dependent transporters. Here, we show that the ΔyqjA mutant (but not ΔyghB) cannot grow under alkaline conditions (ranging from pH 8.5 to 9.5), unlike the parent E. coli. Overexpression of yqjA restores growth at alkaline pH, but only when more than ∼100 mM sodium or potassium is present in the growth medium. Increasing the osmotic pressure by the addition of sucrose enhances the ability of YqjA to support growth under alkaline conditions in the presence of low salt concentrations, consistent with YqjA functioning as an osmosensor. We suggest that YqjA possesses proton-dependent transport activity that is stimulated by osmolarity and that it plays a significant role in the survival of E. coli at alkaline pH.ImportanceThe ability to survive under alkaline conditions is important for many species of bacteria. Escherichia coli can grow at pH 5.5 to 9.5 while maintaining a constant cytoplasmic pH of about 7.6. Under alkaline conditions, bacteria rely upon proton-dependent transporters to maintain a constant cytoplasmic pH. The DedA/Tvp38 protein family is a highly conserved but poorly characterized family of membrane proteins. Here, we show that the DedA/Tvp38 protein YqjA is critical for E. coli to survive at pH 8.5 to 9.5. YqjA requires sodium and potassium for this function. At low cation concentrations, osmolytes, including sucrose, can facilitate rescue of E. coli growth by YqjA at high pH. These data are consistent with YqjA functioning as an osmosensing cation-dependent proton transporter.

Dataset Information

Members of the conserved DedA family are likely membrane transporters and are required for drug resistance in Escherichia coli.

Publications

Members of the conserved DedA family are likely membrane transporters and are required for drug resistance in Escherichia coli.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets