Figure 4.

Constitutive SSTR3 mediates activation of GSK3-β. A, Western blot analysis of GSK3-β pathway activation. The phosphorylation status of GSK3-β Ser9 and the GSK3-β substrate β-catenin A, Ser33/37,Thr42, was assayed in untreated GpSSTR3^WT and GpCon. Relative band intensities of the phosphorylated form of GSK3-β and β-catenin were quantified by densitometry, and the ratios of the phosphorylated to total signals are indicated below the individual phosphorylated blots (n = 3). A representative blot is depicted. B, Dose response of GSK3-β Ser9 phosphorylation state in response to 30-minute stimulation with 8-Br-cAMP in GpSSTR3^WT and GpCon. Relative band intensities of the phosphorylated form of GSK3-β were quantified by densitometry, and the ratios of the phosphorylated to total signals are indicated below the blot (n = 3). Each condition is expressed as fold change from untreated, and a representative blot is depicted.