E-cadΔ70/α localizes to the plasma membrane as a homodimer. (A) Immunofluorescence of endogenous β-catenin in L cells expressing HA-tagged E-cad/α or E-cadΔ70/α. Line scans performed between the indicated arrowheads; the pixel intensity for HA and β-catenin immunofluorescence are shown. Cell–cell junctions indicated with asterisks. (B) Western blot of total cell lysates of L cells expressing E-cad/α-HA or E-cadΔ70/α-HA. β-Catenin level increases threefold when E-cad/α is expressed. GAPDH, loading control. (C) Immunofluorescence staining of endogenous β-catenin in L cells expressing HA-tagged E-cadΔ70/α treated with MG132 to stabilize β-catenin to levels similar to E-cad/α expressing cells. (D) Western blot of total cell lysates of L cells expressing E-cad/α-HA or E-cadΔ70/α-HA treated with MG132 (25 µM, 6 h), showing similar levels of β-catenin. Phosphorylated β-catenin becomes visible upon MG132 treatment (indicated by an asterisk).