Fig. 4.

Effects of MB7 and ouabain on Src and ERKs. A, A549 cells were treated with ouabain or MB7 for 10 min, and cell lysates (50 μg/lane) were separated by SDS polyacrylamide gel electrophoresis and analyzed for Src activation as in Fig. 3. The values are mean ± S.E. from four to six separate experiments. *, p < 0.05 versus control. B, LLC-PK1 cells were treated with MB7 or ouabain for 10 min and immunostained with the ERK/MAPK (phospho-Thr202/Tyr204) phosphorylation/translocation cell-based assay kit (Cayman Chemical) according to the manufacturer's instructions. The images were collected as described under Materials and Methods. Top, representative images from three experiments are shown. Scale bar, 50 μm. Bottom, the quantitative data of phospho-ERK fluorescence intensity were collected from 40 different fields in three independent experiments and expressed as mean ± S.E. *, p < 0.05 versus control.