Figure 6.

A constitutively active MEK1 construct caused normal MDCK cells to lose epithelial cell morphology. Normal MDCK cells were transiently transfected with constitutively active MEK1 cDNA epitope tagged with myc and fixed 24 h after transfection. The cells were immunostained with mouse anti-myc mAb. The myc-positive cells grew on top of untransfected cells, as shown in the combined phase-contrast and fluorescence image (a). These transfected cells formed long processes and were probably migrating (b). The arrowheads indicate the same myc-positive cells in both a and b. Bar, 15 μm.