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Updated: Jul 19, 2026

ABCG5/G8 Crystallization in a Lipidic Bicelle Environment for X-Ray Crystallography
Published on: August 25, 2023
Co-expression of human ABCG5 and ABCG8 in insect cells generates an androstan stimulated membrane ATPase activity
Marianna Müller1, Izabella Klein, Szilárd Kopácsi
1National Medical Center, Institute of Haematology and Immunology, Membrane Research Group of the Hungarian Academy of Sciences, H-1113 Budapest, Hungary.
Abstract:
Mutations in the ATP-binding cassette (ABC) proteins ABCG5 or ABCG8 cause sitosterolemia, a condition with increased accumulation of plant sterols. Upon high level expression of the ABCG5 and ABCG8 proteins in baculovirus-Sf9 cell expression system we found a distinct, vanadate sensitive ATPase activity in isolated membrane preparations only when the two proteins were co-expressed. This ATPase activity was significantly stimulated by the addition of certain androgen hormones and analogs, and was effectively inhibited by progesterone. Our results provide a new aspect of biochemical and functional characterization of the ABCG5/ABCG8 proteins and their possible involvement in steroid hormone transport or regulation.
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