Figure 3.
R141A mutation of the DRY motif rescues constitutive SSTR3 activity. A, hSSTR3 transgene expression in second-generation stable cells postsorting (n = 3). B and C, Dose dependence of intracellular cAMP levels with increasing doses of SRIF-14 in GpSSTR3WT, GpSSTR3R141A, and GpCon: SRIF-14 efficacy (B) and SRIF-14 potency (C), representative of 3 repeated experiments. D, Relative baseline cAMP levels in regenerated stable transfectants (n = 3). E, Relative basal rGH expression in regenerated stable transfectants (n = 3). F, Baseline GSK3-β Ser9 phosphorylation in stable transfectants. 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). A representative blot is depicted. *, P < .05; **, P < .01; N.S., not significant. N/A, not applicable.