Figure 8.

Hyperdopamine induces phosphorylation of β-catenin and β-catenin–NR2B interaction. A, β-Catenin was immunoprecipitated with anti-β-catenin antibody and was then probed for the coimmunoprecipitated NR2B with specific anti-NR2B antibody. Under control conditions, NR2B coprecipitated with β-catenin, whereas β-tubulin was not detected in β-catenin immunoprecipitates (data not shown), suggesting a potential protein interaction between β-catenin and NR2B. Consistently, NR2B binding, as well as input NR2B expression, was significantly decreased by GBR12909 administration (10 mg/kg, i.p.) (p < 0.01). B, The total protein level of β-catenin was not changed by GBR12909 treatment in Western blot detection (p > 0.05). In contrast, the expression of phosphor-β-catenin detected with antibody against Ser33/37/Tyr41 sites was significantly increased by GBR12909 treatment (p < 0.05). These results indicate that β-catenin may mediate the action of GSK-3β in NMDA receptor trafficking and protein synthesis. Error bars indicate SEM.