PT  - JOURNAL ARTICLE
AU  - Aubel, Rémon A. M. H. van
AU  - Kuijck, Marcel A. van
AU  - Koenderink, Jan B.
AU  - Deen, Peter M. T.
AU  - Os, Carel H. van
AU  - Russel, Frans G. M.
TI  - Adenosine Triphosphate-Dependent Transport of Anionic Conjugates by the Rabbit Multidrug Resistance-Associated Protein Mrp2 Expressed in Insect Cells
DP  - 1998 Jun 01
TA  - Molecular Pharmacology
PG  - 1062--1067
VI  - 53
IP  - 6
4099  - http://molpharm.aspetjournals.org/content/53/6/1062.short
4100  - http://molpharm.aspetjournals.org/content/53/6/1062.full
SO  - Mol Pharmacol1998 Jun 01; 53
AB  - The multidrug resistance-associated protein Mrp2 is expressed in liver, kidney, and small intestine and mediates ATP-dependent transport of conjugated organic anions across the apical membrane of epithelial cells. We recently cloned a rabbit cDNA encoding a protein that on basis of highest amino acid homology and tissue distribution was considered to be the rabbit homolog of rat Mrp2. To investigate whether rabbit Mrp2 mediates ATP-dependent transport similar to rat Mrp2, we expressed rabbit Mrp2 in Spodoptera frugiperda (Sf9) cells using recombinant baculovirus. Mrp2 was expressed as an underglycosylated protein in Sf9 cells and to a higher level compared with rabbit liver and renal proximal tubules. Both 17β-estradiol-17-β-d-glucuronide ([3H]E217βG, 50 nm) and [3H]leukotriene C4 (3 nm) were taken up by Sf9-Mrp2 membrane vesicles in an ATP-dependent fashion. Uptake of [3H]E217βG was dependent on the osmolarity of the medium and saturable for ATP (Km = 623 μm). Leukotriene C4, MK571, phenolphthalein glucuronide, and fluorescein-methotrexate were good inhibitors of [3H]E217βG transport. The inhibitory potency of cyclosporin A and methotrexate was moderate, whereas fluorescein, α-naphthyl-β-d-glucuronide, andp-nitrophenyl-β-d-glucuronide did not inhibit transport. In conclusion, we show direct ATP-dependent transport by recombinant rabbit Mrp2 and provide new data on Mrp2 inhibitor specificity. The American Society for Pharmacology and Experimental Therapeutics