Smurf2 induces degradation of GSK-3beta and upregulates beta-catenin in chondrocytes: a potential mechanism for Smurf2-induced degeneration of articular cartilage.

We have previously demonstrated that Smurf2 is highly expressed in human osteoarthritis (OA) tissue, and overexpression of Smurf2 under the control of the type II collagen promoter (Col2a1) induces an OA-like phenotype in aged Col2a1-Smurf2 transgenic mice, suggesting that Smurf2 is located upstream of a signal cascade which initiates OA development. However, the factors downstream of Smurf2 in this signal cascade and how Smurf2-induced OA is initiated are largely unknown. In this study, we further characterized the phenotypic changes in Col2a1-Smurf2 transgenic and WT articular cartilage from the postnatal stage to adulthood.