Inhibition of MPP+ uptake via rOCT1 wild-type (WT) and rOCT1 mutants by three nontransported inhibitors
Uptake measurements were performed at 37°C in stably transfected HEK293 cells using an incubation time of 1 s, except in mutant D475E where a 5-s incubation was performed. Uptake of 0.1 [3H]MPP+ was measured in the presence of different concentrations of TBuA+, TPeA+, and corticosterone. Mean ± S.D. values of three to five separate experiments are shown. The compiled uptake measurements and the calculated Hill coefficients are shown in Figs. 5–7.
rOCT1 | TBuA+ IC50 | TPeA+ IC50 | Corticosterone IC50 |
---|---|---|---|
µM | |||
WT | 0.97 ± 0.22 | 0.27 ± 0.05 | 6.9 ± 1.57 |
F160A | 0.42 ± 0.04# | 0.19 ± 0.04 | 2.36 ± 0.59## |
F160Y | 9.8 ± 1.9*** | 0.33 ± 0.09 | 8.65 ± 0.75 |
W218F | 5.1 ± 0.20*** | 0.03 ± 0.01*** | 18.8 ± 4.3** |
W218Y | 0.48 ± 0.06#,••• | 0.20 ± 0.03•• | 61.5 ± 11.6***,••• |
W218L | 5.13 ± 1.04*** | 0.41 ± 0.05##,••• | 4.07 ± 1.29•• |
Y222F | 0.28 ± 0.06## | 0.18 ± 0.02 | 7.07 ± 1.69 |
T226A | 6.4 ± 1.6*** | 0.30 ± 0.01 | 20.7 ± 6.0** |
R440K | 1.28 ± 0.38 | 0.26 ± 0.05 | 6.00 ± 1.39 |
L447F | 1.40 ± 0.29 | 0.51 ± 0.09** | 8.12 ± 2.32 |
L447Y | 1.04 ± 0.14 | 0.49 ± 0.07** | 20.6 ± 4.0**,□ |
D475E | 0.49 ± 0.10# | 0.12 ± 0.03* | 2.26 ± 0.31## |