FIGURE 9.

Effects of protein kinase inhibitors on α1 internalization. A, cells were treated for 7 h ± 100 nm ouabain and either 1 μm wortmannin or 10 μm PP2. Intracellular biotinylated α1 was quantified and expressed as -fold increase relative to the untreated sample. Means ± S.E. (error bars) of two to four independent experiments is depicted. It all cases the effect of ouabain was highly significant (p < 0.005). B, effect of PP2 on Src phosphorylation. Near-confluent cells were serum-starved for 16 h and incubated for 40 min with either 10 μm PP2 or an equal amount of diluent. Cells were then activated for 15 min with 1 mm NaVO₃ + 3 mm H₂O₂, lysed in radioimmuneprecipitation assay buffer + proteases inhibitors, resolved electrophoretically, and blotted for total and phospho-Src.