Comparison of the substrate specificities among Bsep, mrp2, and mrp6
| Substrate | Control Vesicles | Bsep Vesicles | Mrp2 Vesicles | Mrp6 Vesicles |
|---|---|---|---|---|
| TCA (2 μM) | 1.1 ± 0.8 | 18.3 ± 2.92-150 | 1.1 ± 0.7 | 1.0 ± 0.4 |
| STLC (2 μM) | 3.2 ± 1.7 | 3.7 ± 1.4 | 41.1 ± 3.72-150 | 2.5 ± 0.3 |
| GS-DNP (25 μM) | 6.5 ± 2.4 | 6.3 ± 3.4 | 81.4 ± 7.22-150 | 7.4 ± 0.5 |
| LTC4 (0.05 μM) | 0.7 ± 0.2 | 0.9 ± 0.3 | 3.6 ± 0.32-150 | 0.7 ± 0.04 |
| E-17β-G (10 μM) | 8.5 ± 1.2 | 7.9 ± 0.2 | 56.8 ± 6.52-150 | 7.2 ± 2.6 |
| GSSG (100 μM) | 1.4 ± 1.5 | 1.0 ± 1.3 | 51.7 ± 2.72-150 | 0.3 ± 0.02 |
| BQ-123 (5 μM) | 0.2 ± 0.1 | 0.3 ± 0.1 | 11.6 ± 0.32-150 | 5.9 ± 0.32-150 |
Vesicles were isolated from Sf9 cells infected either with wild-type baculovirus (control) or baculovirus containing Bsep, mrp2, or mrp6. Uptake experiments were performed as described in Materials and Methods. In the case of BQ-123 uptake, the incubation solution was supplemented with 1 mg/ml BSA (protease free; Life Technologies). The following substrates at concentrations given in parentheses were used: TCA, taurocholate; STLC, sulfotaurolithocholic acid; DNP-SG,S-(2,4-dinitrophenyl)-glutathione; LTC4, leukotriene C4; and E-17β-G, estradiol 17β-d-glucuronide. ATP-dependent uptake rates are given as pmol substrate/mg protein × min as mean ± S.D. of triplicate determinations.
↵2-150 Values significantly different from control values (P < .02).