The product of the ABC half-transporter gene ABCG2 (BCRP/MXR/ABCP) is expressed in the plasma membrane.

Abstract

The products of the ABC gene family can be generally classified as either full-transporters of half-transporters. Full-transporters are expressed in the plasma membrane, whereas half-transporters are usually found in intracellular membranes. Recently, an ABC half-transporter, the ABCG2 gene product Breast Cancer/Mitoxantrone Resistance Protein (BCRP/MXR), has been shown to cause mitoxantrone and topotecan resistance. The purpose of this study was to determine the expression and the intracellular localization of this protein in various drug-resistant cell lines. BCRP/MXR expression was determined by Western blot and immunohistochemistry. This protein is highly overexpressed in several drug-resistant cell lines and localizes predominantly to the plasma membrane, instead of to intracellular membranes as seen with all other known half-transporters. Therefore, BCRP/MXR is unique among the ABC half-transporters by being localized to the plasma membrane.

• Authors: E Rocchi, A Khodjakov, E L Volk, C H Yang, T Litman, S E Bates, E Schneider
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 271 Issue 1 Pg. 42-6 (Apr 29 2000) ISSN: 0006-291X [Print] United States
• PMID: 10777678 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)
• Copyright: Copyright 2000 Academic Press.

Chemical References

• ATP-Binding Cassette Transporters

Topics

• ATP-Binding Cassette Transporters (biosynthesis)
• Blotting, Western
• Breast Neoplasms (metabolism)
• Cell Membrane (metabolism)
• Colonic Neoplasms (metabolism)
• Drug Resistance, Neoplasm
• Humans
• Immunohistochemistry
• Microscopy, Fluorescence
• Tumor Cells, Cultured