FIG. 6.

p40 MET expression induces apoptosis of MDCK epithelial cells. (A) MDCK cells were transiently transfected with 1 μg of vector/ml, either empty (−) or expressing wild-type (p40 Met) or kinase-dead (p40 Met KD) p40 MET. Forty-eight hours after transfection, the proteins were resolved by SDS-10% PAGE and analyzed by Western blotting using an anti-Flag antibody (top). The filter was stripped and reprobed sequentially using an anti-phospho-MET antibody and an anti-Erk2 antibody. The same extracts were analyzed by Western blotting using an anti-active caspase 3 antibody. The arrowheads indicate the positions of phosphorylated and nonphosphorylated p40 MET. (B) MDCK cells were transfected with 1 μg of vector/ml expressing either wild-type (p40 Met) or kinase-dead (p40 Met KD) p40 MET. Twenty-four hours after transfection, nuclei were detected by using Hoechst staining (Hoechst; blue staining) and immunofluorescence assays were performed using an anti-Flag antibody (Anti-Flag; green staining) and an anti-cleaved caspase 3 antibody (Anti-cleaved Caspase 3; red staining). An overlay of the three stains is shown (Merge). Percentages of caspase 3-positive cells over p40 MET WT- or KD-transfected cells were determined (n = 3; plus standard deviation). The white arrowheads indicate representative cells expressing transfected p40 MET WT or KD.