Cserepes, Judit and Szentpetery, Zsófia and Seres, László and Ozvegy-Laczka, Csilla and Langmann, Thomas and Schmitz, Gerd and Glavinas, Hristos and Klein, Izabella and Homolya, László and Sarkadi, Balázs and Varadi, András and Elkind, N. Barry (2004) Functional expression and characterization of the human ABCG1 and ABCG4 proteins: indications for heterodimerization. BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 320 (3). pp. 860-867. ISSN 0006-291X, 1090-2104
Full text not available from this repository. (Request a copy)Abstract
The closely related human ABC half-transporters, ABCG1 and ABCG4, have been suggested to play an important role in cellular lipid/sterol regulation but no experimental data for their expression or function are available. We expressed ABCG1 and ABCG4 and their catalytic site mutant variants in insect cells, generated specific antibodies, and analyzed their function in isolated membrane preparations. ABCG1 had a high basal ATPase activity, further stimulated by lipophilic cations and significantly inhibited by cyclosporin A, thyroxine or benzamil. ABCG4 had a lower basal ATPase activity which was not modulated by any of the tested compounds. The catalytic site (K-M) mutants had no ATPase activity. Since dimerization is a requirement for half-transporters, we suggest that both ABCG1 and ABCG4 function as homodimers. Importantly, we also found that co-expression of the ABCG4-KM mutant selectively abolished the ATPase activity of the ABCG1 and therefore they most probably also heterodimerize. The heterologous expression, specific recognition, and functional characterization of these transporters should help to delineate their physiological role and mechanism of action. (C) 2004 Elsevier Inc. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | DROSOPHILA-WHITE GENE; SUBSTRATE-SPECIFICITY; MULTIDRUG TRANSPORTER; RESISTANCE PROTEIN; HUMAN HOMOLOG; INSECT CELLS; MACROPHAGES; ATPASE; EYE; MELANOGASTER; ABC half-transporter; ABCG1; ABCG4; heterodimer; Sf9 cells; drug-stimulated ATPase activity; dominant negative |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Klinische Chemie und Laboratoriumsmedizin |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 07 Jul 2021 05:02 |
| Last Modified: | 07 Jul 2021 05:02 |
| URI: | https://pred.uni-regensburg.de/id/eprint/37425 |
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