Figure 2

PCAF-mediated δ-catenin acetylation promotes autophagic degradation of δ-catenin. (A,B) The acetyltransferase activity of PCAF is required for the downregulation of δ-catenin. However, proteasome inhibition does not suppress the effect of PCAF on downregulating δ -catenin. HEK293Tcells transfected with GFP-δ-catenin and Flag-PCAF (A) and Rv/δ cells transfected with Flag-PCAF (B) were treated with the proteasome inhibitor MG132 (10 μM) or the histone acetyltransferase inhibitor Garcinol (5 µM) or Baf A1 (100 nM) or transfected with shPCAF and incubated for 12 h, and then cell lysates were subjected to immunoblotting. (C) Autophagy inhibitors attenuate PCAF-mediated δ-catenin degradation. HEK293T cells were transfected with the indicated plasmids. At 12 h post-transfection, cells were treated with the autophagy inhibitors chloroquine (CQ, 100 μM), bafilomycin A1 (BafA1, 100 nM), or 3-methyladenine (3-MA, 5 mM), and cell lysates were subjected to immunoblotting. (D) Autophagy inhibitors increase the stability of δ-catenin. HEK293T cells transfected with δ-catenin and treated with 0.2 µM TSA were treated with MG132 (10 μM) or Baf A1 (100 nM) or 3-MA (5 mM) and incubated for 12 h, and then treated with cycloheximide (CHX, 20 ng/ml) for indicated time (h), and then cell lysates were subjected to immunoblotting. α-Tubulin or ß-actin was used as a loading control. Relative δ-catenin/actin ratios from at least three independent experiments are shown as a bar graph in each panel (ii). Values are presented as the mean ± SEM. **p < 0.01; ***p < 0.001; NS, no significant difference compared with the control group. “−”, Mock transfection or vehicle treatment.