Fig. 9.

MMP inhibition reduces GSK3β phosphorylation and activity. (A) Cardiomyocytes were stimulated with TAPI-0 (50 ng/ml) for 5 min up to 2 h. Total cell extracts were prepared and separated on 10% SDS gels. GSK3β activation was determined in Western blots using antibodies specific for P-serine9-GSK3β. Data are expressed as percent increase relative to untreated controls and are means ± SE of nine independent culture preparations. *Differences from unstimulated controls with p < 0.05. (B) Cardiomyocytes were stimulated with TAPI-0 (50 ng/ml) for 1 h. Total cell extracts were prepared, GSK3β was immunoprecipitated, and phosphorylation of GSK3β substrate peptide was determined in vitro. Controls for GSK3β specificity were done either by addition of the GSK3β inhibitor SB 415286 (SB) to the kinase reaction or by omission of GSK3β antibodies (AB) during immunoprecipitation. Data are expressed as percent increase relative to untreated controls and are means ± SE of three independent culture preparations. *Differences from unstimulated controls with p < 0.05. **Differences from unstimulated controls with p < 0.01