Disease relevance of emrE

• This was confirmed by the Southern hybridization of lambda phages covering this region with mvrC probe [1].
• Cloning and characterization of the mvrC gene of Escherichia coli K-12 which confers resistance against methyl viologen toxicity [1].
• A gene coding for a small 110-amino acid membrane protein (emrE or mvrC) has been previously identified and cloned and shown to render Escherichia coli cells resistant to methyl viologen and to ethidium [2].
• The Staphylococcus aureus multidrug-binding protein QacR represses transcription of the plasmid-encoded membrane protein QacA, a multidrug efflux transporter [3].
• Virulence and drug resistance roles of multidrug efflux systems of Salmonella enterica serovar Typhimurium [4].

High impact information on emrE

• In addition, bacterial multidrug efflux determinants are frequently controlled at a global level and may belong to stress response regulons such as E. coli mar, expression of which is controlled by the MarA and MarR proteins [5].
• The TolC channel-tunnel spans the bacterial outer membrane and periplasm, providing a large exit duct for protein export and multidrug efflux when recruited by substrate-engaged inner membrane complexes [6].
• Escherichia coli was found to encode 29 such pumps, and with the exception of the archaebacterium Methanococcus jannaschii, the numbers of multidrug efflux pumps encoded within genomes of the other organisms were found to be approximately proportional to their total numbers of encoded transport systems as well as to total genome size [7].
• The DNA sequence of mvrC gene was determined and its deduced protein encoding a 12 kd hydrophobic protein was confirmed by maxicell labeling of MvrC protein [1].
• Importance of the adaptor (membrane fusion) protein hairpin domain for the functionality of multidrug efflux pumps [8].

Chemical compound and disease context of emrE

• Inducement and reversal of tetracycline resistance in Escherichia coli K-12 and expression of proton gradient-dependent multidrug efflux pump genes [9].
• We cloned a gene for a putative norfloxacin efflux protein from the chromosomal DNA of V. parahaemolyticus by using an Escherichia coli mutant lacking the major multidrug efflux system AcrAB as the host and sequenced the gene (norM) [10].
• Plasmid-encoded multidrug efflux pump conferring resistance to olaquindox in Escherichia coli [11].
• The expression of tripartite multidrug efflux pumps such as MexA-MexB-OprM in Pseudomonas aeruginosa contributes to intrinsic resistance to a wide variety of antimicrobials, including beta-lactams, chloramphenicol, macrolides, quinolones, and tetracycline [12].
• AcrAB multidrug efflux pump is associated with reduced levels of susceptibility to tigecycline (GAR-936) in Proteus mirabilis [13].

Biological context of emrE

• The expression of acrAB, emrAB, emrD, emrE, emrKY, mdfA, and ydgFE is stable at moderate levels during any growth phase, whereas mdtEF promoter activity greatly increased with cell growth and reached the maximum level at the late stationary phase [14].
• Substrate specificity of the RND-type multidrug efflux pumps AcrB and AcrD of Escherichia coli is determined predominantly by two large periplasmic loops [15].
• The mexCD-oprJ and mexAB-oprM operons encode components of two distinct multidrug efflux pumps in Pseudomonas aeruginosa [16].
• Three of the eight sequences matched to genes for multidrug efflux proteins, usher proteins, and pathogenicity island insertion sites, respectively [17].
• A search of the deduced amino acid sequences of EfrA and EfrB revealed that they are similar to each other and that they belong to the ATP-binding cassette (ABC) family of multidrug efflux transporters [18].

Anatomical context of emrE

• NorA functions as a multidrug efflux protein in both cytoplasmic membrane vesicles and reconstituted proteoliposomes [19].
• In gram-negative bacteria, some multidrug efflux systems require two auxiliary constituents, which might enable drug transport to occur across both membranes of the cell envelope [20].

Associations of emrE with chemical compounds

• A new gene mvrC conferring resistance to methyl viologen, a powerful superoxide radical propagator, was cloned on 13.5 kilo base (kb) EcoRI DNA fragment [1].
• Immunoblotting with antibody against AcrA, an obligatory component of the AcrAB multidrug efflux system, showed that this protein was overexpressed by >/=170% in 9 of 10 clinical isolates of Esherichia coli with high-level ciprofloxacin resistance (MICs, >/=32 microg/ml) but not in any of the 15 isolates for which the MIC was </=1 microg/ml [21].
• Disruption of bexA in B. thetaiotaomicron made the strain more susceptible to norfloxacin, ciprofloxacin, and ethidium bromide, showing that this gene is expressed in this organism and functions as a multidrug efflux pump [22].
• The contribution of the AcrAB multidrug efflux system to high-level tetracycline resistance was measured in a Tn10-carrying acrAB null mutant strain [23].
• Conformation of the AcrB Multidrug Efflux Pump in Mutants of the Putative Proton Relay Pathway [24].

Other interactions of emrE

• Overexpression of evgA, a response regulator of a two-component system, increased multidrug efflux in Escherichia coli [25].
• Cell division defects in Escherichia coli deficient in the multidrug efflux transporter AcrEF-TolC [26].

Analytical, diagnostic and therapeutic context of emrE

• The similar numbers of chromosomally encoded multidrug efflux systems in pathogens and nonpathogens suggests that these transporters have not arisen recently in pathogens in response to antimicrobial chemotherapy [7].
• The multidrug efflux regulator TtgV recognizes a wide range of structurally different effectors in solution and complexed with target DNA: evidence from isothermal titration calorimetry [27].
• A periplasmic drug-binding site of the AcrB multidrug efflux pump: a crystallographic and site-directed mutagenesis study [28].
• Lipid-layer crystallization and preliminary three-dimensional structural analysis of AcrA, the periplasmic component of a bacterial multidrug efflux pump [29].
• Molecular cloning and characterization of the HmrM multidrug efflux pump from Haemophilus influenzae Rd [30].

References