wt Ecad and cis-Ecad expression restore Ecad-dependent cell–cell contacts in A431D cells. (A) Fluorescence imaging of cells expressing wt Ecad-GFP (wt Ecad) or cis-Ecad-GFP (cis-Ecad) reveals indistinguishable coaccumulation of Ecad and α-catenin at cell–cell contacts. Bar, 20 µm. (B) GFP-tagged proteins were immunoprecipitated from transfected cell lysates and subjected to Western blotting to detect GFP and α-catenin (Bound). Western blot of the cellular extracts before immunoprecipitation is shown on the left (Input). CAAX-GFP expressing cells were used as a control. Both wt Ecad-GFP and cis-Ecad-GFP were expressed at the predicted molecular mass (140 kD) and at similar levels (Input). α-Catenin was coimmunoprecipitated at similar levels with wt Ecad-GFP and cis-Ecad-GFP. (C) Representative distributions of cell surface–associated fluorescent intensities (arbitrary units [au]) for wt and cis-Ecad-GFP–transfected cells, 24 h after transfection (1,500 and 1,300 objects analyzed, respectively). The histogram represents the mean of the median fluorescent intensities ± SEM obtained from three independent experiments.