Figure 7.

Transfection of MDCK II cells with a constitutively active MEK1 cDNA disrupted E-cadherin and occludin distribution. The transfected MDCK cells were double immunolabeled with antibodies against E-cadherin (a) and myc (b), occludin (c) and myc (d), or ZO-1 (e) and myc (f). The distribution of E-cadherin and occludin in myc-positive cells (a and c, arrowheads) was disrupted compared with that in untransfected cells. In contrast, the localization of ZO-1 in myc-positive cells (e, arrowheads) was intact, although these cells clearly extended processes beneath adjacent cells (f). Arrowheads in b, d, and f locate the same cells indicated in a, c, and e. Bar, 15 μm.