Disruption of the Unique ABCG-Family NBD:NBD Interface Impacts Both Drug Transport and ATP Hydrolysis

Kapoor, Parth; Briggs, Deborah A.; Cox, Megan H.; Kerr, Ian D.

Abstract

ABCG2 is one of a triumvirate of human multidrug ATP binding cassette (ABC) transporters that are implicated in defense of cells and tissues against cytotoxic chemicals, but which can confer chemotherapy resistance states in oncology. Understanding the mechanism of ABCG2 is thus imperative if we are to be able to counter its deleterious activity. The structure of ABCG2 and related family members (ABCG5/G8) demonstrated that there were two interfaces between the nucleotide binding domains. In addition to the canonical ATP “sandwich-dimer” interface, there was a second contact region between residues at the C-terminus of the NBD. We mutated this second interface by making mutations to a series of residues which are in close interaction with the opposite NBD. Mutated ABCG2 isoforms were expressed in HEK293T cells and analyzed for targeting to the membrane, drug transport and ATPase activity. Mutations to this second interface had a number of effects on ABCG2 including altered drug specificity, altered drug transport and, in two mutants, a loss of ATPase activity. The results demonstrate that this region is particularly sensitive to mutation and can impact upon both direct, local NBD events (i.e. ATP hydrolysis) but also on the allosteric communication to the transmembrane domains and drug transport.

Citation

Kapoor, P., Briggs, D. A., Cox, M. H., & Kerr, I. D. (2020). Disruption of the Unique ABCG-Family NBD:NBD Interface Impacts Both Drug Transport and ATP Hydrolysis. International Journal of Molecular Sciences, 21(3), Article 759. https://doi.org/10.3390/ijms21030759

• Journal Article Type: Article
• Acceptance Date: Jan 21, 2020
• Online Publication Date: Jan 23, 2020
• Publication Date: Jan 23, 2020
• Deposit Date: Jan 23, 2020
• Publicly Available Date: Jan 23, 2020
• Journal: International Journal of Molecular Sciences
• Print ISSN: 1661-6596
• Electronic ISSN: 1422-0067
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 21
• Issue: 3
• Article Number: 759
• DOI: https://doi.org/10.3390/ijms21030759
• Keywords: Physical and Theoretical Chemistry; Inorganic Chemistry; Organic Chemistry; Spectroscopy; Molecular Biology; Catalysis; General Medicine; Computer Science Applications
• Public URL: https://nottingham-repository.worktribe.com/output/3788011
• Publisher URL: https://www.mdpi.com/1422-0067/21/3/759