Characterization of the ATPase activity of human ATP-binding cassette transporter-2 (ABCA2).
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International Institute of Anticancer Research
BACKGROUND: ABCA2 is a member of the ATP binding cassette transporter family with functional roles in cholesterol homeostasis and drug resistance.
MATERIALS AND METHODS: In order to characterize its ATPase activity, we transfected HEK293 cells with an ABCA2 mammalian expression system and isolated ABCA2-enriched membranes.
RESULTS: We found no measurable ATPase activity of ABCA2 in isolated membranes, except in the presence of the methyl-beta-cyclodextrin. However, competitive binding of a pseudo-substrate, 8-azido-[alpha-32P]-ATP, was demonstrated. CHO cells transfected with ABCA2 did not have a higher rate of endogenous ATP hydrolysis when compared to the mock-transfected cells.
CONCLUSION: Overall, we conclude that, while ABCA2 may have low levels of ATPase activity that can be substrate-stimulated, it is more likely to have a regulatory role in cell physiology.
Medical Specialties | Medicine and Health Sciences | Osteopathic Medicine and Osteopathy
3T3 Cells, ATP-Binding Cassette Transporters, Adenosine Triphosphatases, Animals, CHO Cells, Cloning, Molecular, Cricetinae, Cricetulus, Fibroblasts, Gene Expression Regulation, Enzymologic, Humans, Intracellular Membranes, Isoenzymes, Kidney, Mice, Rabbits, Transfection, beta-Cyclodextrins
Beljanski, Vladimir; Soulika, Athena; Tucker, Jody M; Townsend, Danyelle M; Davis, Warren; and Tew, Kenneth D, "Characterization of the ATPase activity of human ATP-binding cassette transporter-2 (ABCA2)." (2005). Faculty Articles. 1558.