Fig. 4. Post-translational accumulation of ß-catenin during de-differentiation of chondrocytes. (A) Chondrocytes were untreated or treated with 5 ng/ml IL1ß or 1 µM RA for 72 hours, and ß-catenin and phosphorylated GSK-3ß was determined by western (WB) or northern (NB) blotting. (B) Chondrocytes were treated with the indicated concentrations of LiCl for 48 hours. ß-Catenin, type II collagen and phosphorylated GSK-3ß was determined by western blotting. (C) Chondrocytes were treated with the indicated concentrations of MG132 for 48 hours. ß-Catenin and type II collagen was determined by western blotting. ERK-2 was detected as loading control of blots.