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Reference: Velamakanni, S, Lau, CH, Gutmann, DA et al., (2009). A multidrug ABC transporter with a taste for salt. PloS one, 4 (7), e6137.Citable link to this page:


A multidrug ABC transporter with a taste for salt.

Abstract: BACKGROUND: LmrA is a multidrug ATP-binding cassette (ABC) transporter from Lactococcus lactis with no known physiological substrate, which can transport a wide range of chemotherapeutic agents and toxins from the cell. The protein can functionally replace the human homologue ABCB1 (also termed multidrug resistance P-glycoprotein MDR1) in lung fibroblast cells. Even though LmrA mediates ATP-dependent transport, it can use the proton-motive force to transport substrates, such as ethidium bromide, across the membrane by a reversible, H(+)-dependent, secondary-active transport reaction. The mechanism and physiological context of this reaction are not known. METHODOLOGY/PRINCIPAL FINDINGS: We examined ion transport by LmrA in electrophysiological experiments and in transport studies using radioactive ions and fluorescent ion-selective probes. Here we show that LmrA itself can transport NaCl by a similar secondary-active mechanism as observed for ethidium bromide, by mediating apparent H(+)-Na(+)-Cl(-) symport. Remarkably, LmrA activity significantly enhances survival of high-salt adapted lactococcal cells during ionic downshift. CONCLUSIONS/SIGNIFICANCE: The observations on H(+)-Na(+)-Cl(-) co-transport substantiate earlier suggestions of H(+)-coupled transport by LmrA, and indicate a novel link between the activity of LmrA and salt stress. Our findings demonstrate the relevance of investigations into the bioenergetics of substrate translocation by ABC transporters for our understanding of fundamental mechanisms in this superfamily. This study represents the first use of electrophysiological techniques to analyze substrate transport by a purified multidrug transporter.

Publication status:Published Funder: Biotechnology and Biological Sciences Research Council   Funder: Medical Research Council   Funder: Royal Society   Notes:Copyright 2009 Velamakanni et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Bibliographic Details

Publisher: Public Library of Science

Publisher Website: http://www.plos.org

Journal: PloS onesee more from them

Publication Website: http://www.plosone.org

Issue Date: 2009

pages:Article: e6137


Urn: uuid:f673e99c-58a6-43fb-838c-583f7531f11b

Source identifier: 59329

Eissn: 1932-6203

Doi: https://doi.org/10.1371/journal.pone.0006137

Issn: 1932-6203 Item Description

Type: Journal article;

Language: eng Keywords: Protons ATP-Binding Cassette Transporters Multidrug Resistance-Associated Proteins DNA Primers Bacterial Proteins Spectrometry, Mass, Electrospray Ionization Base Sequence Ion Transport Mutagenesis, Site-Directed Sodium Chloride Tiny URL: pubs:59329


Author: Velamakanni, S - - - Lau, CH - - - Gutmann, DA - - - Venter, H - - - Barrera, NP - - - Seeger, MA - - - Woebking, B - - - Matak-V

Source: https://ora.ox.ac.uk/objects/uuid:f673e99c-58a6-43fb-838c-583f7531f11b


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