FIGURE 4:

Presence of α-catenin in the cadherin–catenin complex strengthens cadherin–p120 interactions. (A) Digitonin cell lysates of the Ec1M- and EcM-Δ844–expressing cells (Ec1M and Ec1M-Δ844, respectively) were immunoprecipitated by the anti-myc antibody, and the resulting immunoprecipitates were washed with the digitonin buffer (Ctrl) or the same buffer containing either 0.2% Triton X-100 (T-100) or 0.45 M NaCl (NaCl). The immunoprecipitates were probed using anti-myc (myc) or anti-p120 (p120) antibodies. Note that the addition of Triton X-100 or NaCl into the washing buffer nearly completely removed p120 from the Ec1M-Δ844 but not Ec1M immunoprecipitates. (B) The endogenous E-cadherin was immunoprecipitated as in A using anti-E-cadherin SHE78-7 antibody from α-catenin–positive A-431 cells (A431), α-catenin–deficient MDA-MB-468 cells (MB468), and MDA-MB-468α cells (MBD468α), in which α-catenin expression was reconstituted. Blots were stained for the immunoprecipitated E-cadherin (Ec) or coimmunoprecipitated p120 (p120).