FIGURE 5.

AKT and GSK3 modulate TAZ stability via the N-terminal phosphodegron. A, interaction between the N-terminal phosphodegron and β-TrCP. The indicated plasmids were transfected into 293T cells. Co-immunoprecipitation was performed to determine the interaction between TAZ^S311A and β-TrCP. The TAZ^S311A mutant displayed a low level interaction with β-TrCP, which was further decreased by mutation of the N-terminal phosphodegron or GSK3 inhibition by LiCl. Treatment with PI3K inhibitor (LY294002 or wortmannin) or GSK3 inhibitor (LiCl) is indicated. B, TAZ^S58A/S62A mutant is resistant to PI3K inhibitor-induced degradation. NIH3T3 cells stably expressing vector, TAZ, and TAZ^S58A/S62A were treated as indicated, and cell lysates were analyzed by WB. C, TAZ was stabilized by mutation of phosphorylation sites in N-terminal phosphodegron. The half-lives of TAZ mutants in NIH3T3 cells stably expressing TAZ and TAZ^S58A/S62A were analyzed by WB. Relative TAZ levels were quantified by the ratio between TAZ and GAPDH. Error bars, S.D.