Promiscuous partnering and independent activity of MexB, the multidrug transporter protein from Pseudomonas aeruginosa

2010 ◽  
Vol 430 (2) ◽  
pp. 355-364 ◽  
Author(s):  
Alexander Welch ◽  
Chidiebere U. Awah ◽  
Shiheng Jing ◽  
Hendrik W. van Veen ◽  
Henrietta Venter

The MexAB–OprM drug efflux pump is central to multidrug resistance of Pseudomonas aeruginosa. The ability of the tripartite protein to confer drug resistance on the pathogen is crucially dependent on the presence of all three proteins of the complex. However, the role of each protein in the formation of the intact functional complex is not well understood. One of the key questions relates to the (in)ability of MexB to act independently of its cognitive partners, MexA and OprM. In the present study, we have demonstrated that, in the absence of MexA and OprM, MexB can: (i) recruit AcrA and TolC from Escherichia coli to form a functional drug-efflux complex; (ii) transport the toxic compound ethidium bromide in a Gram-positive organism where the periplasmic space and outer membrane are absent; and (iii) catalyse transmembrane chemical proton gradient (ΔpH)-dependent drug transport when purified and reconstituted into proteoliposomes. Our results represent the first evidence of drug transport by an isolated RND (resistance–nodulation–cell division)-type multidrug transporter, and provide a basis for further studies into the energetics of RND-type transporters and their assembly into multiprotein complexes.

2018 ◽  
Vol 7 (2) ◽  
pp. 408-419 ◽  
Author(s):  
Takao Nakanishi ◽  
Toshi Menju ◽  
Shigeto Nishikawa ◽  
Koji Takahashi ◽  
Ryo Miyata ◽  
...  

1999 ◽  
Vol 277 (1) ◽  
pp. F84-F96 ◽  
Author(s):  
Shinya Ito ◽  
Cindy Woodland ◽  
Balázs Sarkadi ◽  
Guido Hockmann ◽  
Scott E. Walker ◽  
...  

P-glycoprotein (P-gp) on the apical membranes of epithelial cells is known as a drug efflux pump. However, unclear is its integral quantitative role in the overall epithelial drug transfer, which also involves distinct diffusion processes in parallel and sequence. We used a simple three-compartment model to obtain kinetic parameters of each drug transfer mechanism, which can quantitatively describe the transport time courses of P-gp substrates, digoxin and vinblastine, across P-gp-expressing MDCK cell monolayers grown on permeable filters. Our results show that the model, which assumes a functionally single drug efflux pump in the apical membrane with diffusion across two membranes and intercellular junctions, is the least complex model with which to quantitatively reproduce the characteristics of the data. Interestingly, the model predicts that the MDCK apical membranes are less diffusion permeable than the basolateral membrane for both drugs and that the distribution volume of vinblastine is 10-fold higher than that of digoxin. Additional experiments verified these model predictions. The modeling approach is feasible to quantitatively describe overall kinetic picture of epithelial drug transport. Further model refinement is necessary to incorporate other modes of drug transport such as transcytosis. Also, whether P-gp solely accounts for the pump function in this model awaits more studies.


2015 ◽  
Vol 35 (4) ◽  
Author(s):  
Ameena J. Haider ◽  
Megan H. Cox ◽  
Natalie Jones ◽  
Alice J. Goode ◽  
Katherine S. Bridge ◽  
...  

Determining how efflux pumps function is important to understanding their role in drug resistance. We have identified amino acids in a human drug efflux pump that affect interaction with substrate and protein targeting.


2020 ◽  
Vol 20 (2) ◽  
pp. 271-287 ◽  
Author(s):  
Manaf AlMatar ◽  
Işıl Var ◽  
Begüm Kayar ◽  
Fatih Köksal

Background: Numerous investigations demonstrate efflux as a worldwide bacterial mode of action which contributes to the resistance of drugs. The activity of antibiotics, which subjects to efflux, can be improved by the combined usage of efflux inhibitors. However, the efflux role to the overall levels of antibiotic resistance of clinical M. tuberculosis isolates is inadequately comprehended and is still disregarded by many. Method: Here, we assessed the contribution of resistant genes associated with isoniazid (INH) and rifampin (R) resistance to the levels of drug resistance in the (27) clinical isolates of MDR-TB. Additionally, the role of the resistance for six putative drug efflux pump genes to the antibiotics was investigated. The level of katG expression was down-regulated in 24/27 (88.88%) of MDR-TB isolates. Of the 27 MDR-TB isolates, inhA, oxyR-ahpC, and rpoB showed either overexpression or up-regulation in 8 (29.62%), 4 (14.81 %), and 24 (88.88%), respectively. Moreover, the efflux pump genes drrA, drrB, efpA, Rv2459, Rv1634, and Rv1250 were overexpressed under INH/RIF plus fresh pomegranate juice (FPJ) stress signifying the efflux pumps contribution to the overall levels of the resistance of MDR-TB isolates. Conclusion: These results displayed that the levels of drug resistance of MDR-TB clinical isolates are due to combination among drug efflux pump and the presence of mutations in target genes, a truth which is often ignored by the specialists of tuberculosis in favour of the almost undoubted significance of drug target- gene mutations for the resistance in M. tuberculosis.


Microbiology ◽  
2009 ◽  
Vol 155 (10) ◽  
pp. 3312-3321 ◽  
Author(s):  
Masaki Yamamoto ◽  
Atsuhisa Ueda ◽  
Makoto Kudo ◽  
Yasuhiro Matsuo ◽  
Jun Fukushima ◽  
...  

MexXY, a drug efflux pump in Pseudomonas aeruginosa, confers resistance to aminoglycoside antibiotics. We recently reported that MexZ binds to the promoter region of the mexXY operon. Electrophoretic mobility shift assay (EMSA) using recombinant MexZ and oligonucleotide probes prepared from the intergenic region between mexZ and mexX revealed that MexZ binds to a 20 bp palindromic sequence. Culture of P. aeruginosa in the presence of tetracycline induced higher levels of MexX and MexZ, as measured by immunoblotting and EMSA, than in the absence of antibiotics. When MexZ was expressed by a mexZ expression plasmid, the plasmid-borne MexZ repressed drug-induced MexX production, further confirming that MexZ acts as a repressor of the mexXY operon. PA5471 protein has been reported to be essential for drug-induced MexXY production. Similarly to that report, we observed that plasmid-borne PA5471 induced both MexX and MexZ production in PAO1 cells. Interestingly, interaction between MexZ and PA5471 was observed in a yeast two-hybrid assay. Furthermore, EMSA and in vitro transcription assays revealed that interaction between PA5471 and MexZ reduced MexZ DNA-binding ability, leading to mexXY transcription. These findings contribute to the understanding of the molecular mechanisms underlying the transcriptional regulation of mexZ and mexXY by drug-induced PA5471 expression.


2009 ◽  
Vol 53 (12) ◽  
pp. 5312-5316 ◽  
Author(s):  
Vijaya Bharathi Srinivasan ◽  
Govindan Rajamohan ◽  
Wondwossen A. Gebreyes

ABSTRACT In this study, a chromosomally encoded putative drug efflux pump of the SMR family, named AbeS, from a multidrug-resistant strain of Acinetobacter baumannii was characterized to elucidate its role in antimicrobial resistance. Expression of the cloned abeS gene in hypersensitive Escherichia coli host KAM32 resulted in decreased susceptibility to various classes of antimicrobial agents, detergents, and dyes. Deletion of the abeS gene in A. baumannii confirmed its role in conferring resistance to these compounds.


2021 ◽  
Vol 22 (10) ◽  
pp. 5328
Author(s):  
Miao Ma ◽  
Margaux Lustig ◽  
Michèle Salem ◽  
Dominique Mengin-Lecreulx ◽  
Gilles Phan ◽  
...  

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans.


Life Sciences ◽  
1992 ◽  
Vol 51 (18) ◽  
pp. 1427-1437 ◽  
Author(s):  
Akira Tsuji ◽  
Tetsuya Terasaki ◽  
Yasushi Takabatake ◽  
Yoshiyuki Tenda ◽  
Ikumi Tamai ◽  
...  

2021 ◽  
Vol 1225 ◽  
pp. 129279
Author(s):  
Shyam Goswami ◽  
Arabinda Ghosh ◽  
Karmajyoti Borah ◽  
Anupam Mahanta ◽  
Ankur K Guha ◽  
...  

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