GSK3B and gastric cancer: In addition, knockdown of CDK5RAP3 in gastric cancer cells led to upregulated AKT phosphorylation at Ser473, GSK-3β phosphorylation at Ser9 and β-catenin expression, whereas overexpression of CDK5RAP3 led to the opposite effects (Fig. 1d), indicating that CDK5RAP3 may regulate β-catenin activity by suppressing AKT phosphorylation at Ser473.