Table 1.
Effect of phospholipids and WM on ATP-dependent taurocholate and DNP-GSH transport at 1 min in CMV
| Taurocholate transport
|
DNP-GSH transport
|
|||
|---|---|---|---|---|
| CMV | CMV + PC | CMV | CMV + PC | |
| ATP | 32.7 ± 5.9 | 3.5 ± 0.6 | 25.1 ± 2.1 | 4.0 ± 0.8 |
| ATP + WM | 7.5 ± 1.5 | 0.4 ± 0.2 | 8.2 ± 1.1 | ND |
| ATP + PI 3,4-P2 | ND | 49.9 ± 7.5 | ND | 101.5 ± 18.7 |
| ATP + WM + PI 3,4-P2 | ND | 29.8 ± 3.7 | ND | 50.2 ± 10.5 |
| ATP + PI 3,4,5-P3 | ND | 34.6 ± 6.2 | ND | 35.3 ± 4.2 |
| ATP + WM + PI 3,4,5-P3 | ND | 24.2 ± 3.8 | ND | 33.8 ± 4.0 |
| ATP + PI 4,5-P2 | ND | 2.8 ± 0.6 | ND | ND |
Sonicated lipids (200 μM PC or 200 μM PS with 10 μM PI 3,4-P2, PI 3,4,5-P3, or PI 4,5,-P2, final concentrations) were incubated for 10 min with CMV at 37°C. Wortmannin (100 nM) was added for the last 5 min before initiation of transport assay. Transport was measured at 1 min and was expressed as picomoles of taurocholate or DNP-GSH transported/mg protein. The results are expressed as means ± SD for taurocholate (n = 6) and means ± standard error for DNP-GSH (n = 2). ND, not determined; WM, wortmannin; CMV, canalicular membrane vesicle.