title: Co-expression of human ABCG5 and ABCG8 in insect cells generates an androstan stimulated membrane ATPase activity.
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.
authors.affiliation: National Medical Center, Institute of Haematology and Immunology, Membrane Research Group of the Hungarian Academy of Sciences, H-1113 Budapest, Hungary.
authors.forename: Marianna
authors.initials: M
authors.lastname: Müller
authors.forename: Izabella
authors.initials: I
authors.lastname: Klein
authors.forename: Szilárd
authors.initials: S
authors.lastname: Kopácsi
authors.forename: Alan T
authors.initials: AT
authors.lastname: Remaley
authors.forename: Eva
authors.initials: E
authors.lastname: Rajnavölgyi
authors.forename: Balázs
authors.initials: B
authors.lastname: Sarkadi
authors.forename: András
authors.initials: A
authors.lastname: Váradi
mesh_terms: D000071018:ATP Binding Cassette Transporter, Subfamily G, Member 5; D000071019:ATP Binding Cassette Transporter, Subfamily G, Member 8; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000502:physiology*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000728:Androgens / Q000494:pharmacology; D000731:Androstanes / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D006728:Hormones / Q000378:metabolism; D006801:Humans; D007313:Insecta; D008074:Lipoproteins / Q000235:genetics / Q000502:physiology*; D008565:Membrane Proteins; D011374:Progesterone / Q000494:pharmacology; D014161:Transduction, Genetic; D014638:Vanadates
chemical_list: C416945:ABCG5 protein, human; C416946:ABCG8 protein, human; D000071018:ATP Binding Cassette Transporter, Subfamily G, Member 5; D000071019:ATP Binding Cassette Transporter, Subfamily G, Member 8; D018528:ATP-Binding Cassette Transporters; D000728:Androgens; D000731:Androstanes; D006728:Hormones; D008074:Lipoproteins; D008565:Membrane Proteins; D014638:Vanadates; D011374:Progesterone; D000251:Adenosine Triphosphatases