Effect of cysteine mutagenesis on the function and disulfide bond formation of human ABCG2.

ABSTRACT: ABCG2 is a member of the ATP-binding cassette (ABC) transporter superfamily. Its overexpression causes multidrug resistance in cancer chemotherapy. Based on its apparent half size in sequence when compared with other traditional ABC transporters, ABCG2 has been thought to exist and function as a homodimer linked by intermolecular disulfide bonds. However, recent evidence suggests that ABCG2 may exist as a higher form of oligomers due to noncovalent interactions. In this study, we attempted to create a cysless mutant ABCG2 as a tool for further characterization of this molecule. However, we found that the cysless mutant ABCG2 is well expressed but not functional. Mapping of the cysteine residues showed that three cysteine residues (Cys284, Cys374, and Cys438) are required concurrently for t

SUBMITTER: Liu Y 

PROVIDER: S-EPMC2632310 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature