The Dutch Journal published by springer netherlands, Journal of Bioenergetics and Biomembranes

ABCG2 (also termed the breast cancer resistance protein) has been identified as a multidrug transporter that confers resistance on tumor cells. Evidence will be summarized suggesting that ABCG2 can also mediate the binding/transport of non-drug substrates, including free and conjugated steroids. The characterization of the substrate specificities of ABCG proteins at a molecular level might provide further clues about their potential physiological role(s), and create new opportunities for the modulation of their activities in relation to human disease.

Saroj Velamakanni¹, Shen L. Wei¹, Tavan Janvilisri¹ and Hendrik W. van Veen¹ 

(1)	Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK

Published online: 8 November 2007

Abstract  The ATP-binding cassette (ABC) transporter superfamily is one of the largest protein families with representatives in all kingdoms of life. Members of this superfamily are involved in a wide variety of transport processes with substrates ranging from small ions to relatively large polypeptides and polysaccharides. The G subfamily of ABC transporters consists of half-transporters, which oligomerise to form the functional transporter. While ABCG1, ABCG4 and ABCG5/8 are involved in the ATP-dependent translocation of steroids and, possibly, other lipids, ABCG2 (also termed the breast cancer resistance protein) has been identified as a multidrug transporter that confers resistance on tumor cells. Evidence will be summarized suggesting that ABCG2 can also mediate the binding/transport of non-drug substrates, including free and conjugated steroids. The characterization of the substrate specificities of ABCG proteins at a molecular level might provide further clues about their potential physiological role(s), and create new opportunities for the modulation of their activities in relation to human disease.

Keywords  ABC transporter - ABCG family - Breast cancer resistance protein (BCRP) - Steroid transport - Multidrug resistance

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ABCG transporters: structure, substrate specificities and physiological roles

A Brief Overview

Journal	Journal of Bioenergetics and Biomembranes
Publisher	Springer Netherlands
ISSN	0145-479X (Print) 1573-6881 (Online)
Status
Category	Transport ATPases: Structure, Mechanism and Relevance to Multiple Diseases
DOI	10.1007/s10863-007-9122-x
Subject Collection	Chemistry and Materials Science
SpringerLink Date	Thursday, November 08, 2007