Glutathione Transport Is a Unique Function of the ATP-binding Cassette Protein ABCG2 [2010[(IR91)

Glutathione Transport Is a Unique Function of the ATP-binding Cassette Protein ABCG2 [2010[(IR91)

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(Memo Item created on December 16, 2010 07:55 PM)
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Glutathione Transport Is a Unique Function of the ATP-binding Cassette Protein ABCG2

http://www.jbc.org/content/285/22/16582
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First Published on March 23, 2010, doi: 10.1074/jbc.M109.090506
May 28, 2010 The Journal of Biological Chemistry, 285, 16582-16587.

Glutathione Transport Is a Unique Function of the ATP-binding Cassette Protein ABCG2 *
Heather M. Brechbuhl‡, Neal Gould§, Remy Kachadourian¶, Wayne R. Riekhof¶, Dennis R. Voelker¶ and Brian J. Day§¶‖**,1
- Author Affiliations

From the Departments of ‖Medicine,
**Immunology, and
§Pharmaceutical Sciences, University of Colorado Denver Health Sciences Center, Aurora, Colorado 80045 and
the Departments of ¶Medicine and
‡Pediatrics, National Jewish Health, Denver, Colorado 80206
1 To whom correspondence should be addressed: National Jewish Health, 1400 Jackson St., Denver, CO 80206. Tel.: 303-398-1121; Fax: 303-270-2263; E-mail: dayb@njhealth.org.
Abstract

Glutathione (GSH) transport is vital for maintenance of intracellular and extracellular redox balance. Only a few human proteins have been identified as transporters of GSH, glutathione disulfide (GSSG) and/or GSH conjugates (GS-X). Human epithelial MDA1586, A549, H1975, H460, HN4, and H157 cell lines were exposed to 2′,5′-dihydroxychalcone, which induces a GSH efflux response. A real-time gene superarray for 84 proteins found in families that have a known role in GSH, GSSG, and/or GS-X transport was employed to help identify potential GSH transporters. ABCG2 was identified as the only gene in the array that closely corresponded with the magnitude of 2′,5′-dihydroxychalcone (2′,5′-DHC)-induced GSH efflux. The role of human ABCG2 as a novel GSH transporter was verified in a Saccharomyces cerevisiae galactose-inducible gene expression system. Yeast expressing human ABCG2 had 2.5-fold more extracellular GSH compared with those not expressing ABCG2. GSH efflux in ABCG2-expressing yeast was abolished by the ABCG2 substrate methotrexate (10 μM), indicating competitive inhibition. In contrast, 2′,5′-DHC treatment of ABCG2-expressing yeast increased extracellular GSH levels in a dose-dependent manner with a maximum 3.5-fold increase in GSH after 24 h. In addition, suppression of ABCG2 with short hairpin RNA or ABCG2 overexpression in human epithelial cells decreased or increased extracellular GSH levels, respectively. Our data indicate that ABCG2 is a novel GSH transporter.

ABC Transporter Antioxidant Membrane Proteins Transport Amino Acids Yeast Glutathione
Footnotes

↵* This work was supported, in whole or in part, by National Institutes of Health Grants R01 HL084469 (to B. J. D.), R01 HL075523 (to B. J. D), R01 ES0175825, R37-GM32453 (to D. R. V), and 1F32-GM076798 (to W. R. R.). This work was also supported by American Cancer Society Great-West Division Postdoctoral Fellowship Award PF-06-288-01-CSM (to W. R. R.).

↵ The on-line version of this article (available at http://www.jbc.org) contains supplemental Experimental Procedures and additional references, Figs. 1–5, and Table 1.

Received December 2, 2009.
Revision received March 23, 2010.
© 2010 by The American Society for Biochemistry and Molecular Biology, Inc.
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