Figure 8. Proposed model of regulation of PME-1 expression by PI3K-GSK-3β signaling. Activation of PI3K signaling results in phosphorylation of GSK-3β and inhibition its activity in phosphorylating β-catenin. β-catenin translocates to nucleus and act as co-activator with LEF1/TCF to promote PME-1 expression, which catalyzes the demethylation of PP2Ac.