Purification and structural analyses of ABCG2.
ABCG2 is best known as a multidrug transporter capable of conferring resistance to cancer cells. However, the protein is also inherently expressed in numerous barrier tissues and intriguingly within hematopoietic stem cells. Unlike its partners ABCB1 and ABCC1, there is considerably less information available on the molecular mechanism of ABCG2. The transporter has a distinct topology and is presumed to function as a homodimer. However, a number of biochemical studies have presented data to suggest that the protein adopts higher order oligomers. This review focuses on this controversial issue with particular reference to findings from low resolution structural data. In addition, a number of molecular models of ABCG2 based on high resolution structures of bacterial ABC transporters have recently become available and are critically assessed. ABCG2 is a structurally distinct member of the triumvirate of human multidrug transporters and continues to evade description of a unifying molecular mechanism.
McDevitt
Christopher A
CA
Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, United Kingdom.
Collins
Richard
R
Kerr
Ian D
ID
Callaghan
Richard
R
D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D018432:Drug Resistance, Multiple / Q000502:physiology; D006801:Humans; D008958:Models, Molecular; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D011487:Protein Conformation
C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D009363:Neoplasm Proteins