Is ATP binding responsible for initiating drug translocation by the multidrug transporter ABCG2?

Christopher A. McDevitt, Emily Crowley, Gemma Hobbs, Kate J. Starr, Ian D. Kerr, Richard Callaghan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

ABCG2 confers resistance to cancer cells by mediating the ATP-dependent outward efflux of chemotherapeutic compounds. Recent studies have indicated that the protein contains a number of interconnected drug binding sites. The present investigation examines the coupling of drug binding to ATP hydrolysis. Initial drug binding to the protein requires a high-affinity interaction with the drug binding site, followed by transition and reorientation to the low-affinity state to enable dissociation at the extracellular face. [3H]Daunomycin binding to the ABCG2R482G isoform was examined in the nucleotide-bound and post-hydrolytic conformations. Binding of [ 3H]daunomycin was displaced by ATP analogues, indicating transition to a low-affinity conformation prior to hydrolysis. The low-affinity state was observed to be retained immediately post-hydrolysis. Therefore, the dissociation of phosphate and/or ADP is likely to be responsible for resetting of the transporter. The data indicate that, like ABCB1 and ABCC1, the 'power stroke' for translocation in ABCG2R482G is the binding of nucleotide.

Original languageEnglish
Pages (from-to)4354-4362
Number of pages9
JournalFEBS Journal
Volume275
Issue number17
DOIs
Publication statusPublished - Sept 2008
Externally publishedYes

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