FIGURE 2.

TAZ protein level is regulated by PI3K and AKT. A, PI3K inhibitor LY294002 decreases TAZ protein levels. NIH3T3 cells were treated with PI3K inhibitor LY294002 at the indicated concentrations for 6 h (top) or as 30 μm for indicated times (bottom). Cell lysates were analyzed by WB. B, LY294002-induced TAZ degradation is blocked by MG132. HeLa and NIH3T3 cells were treated with or without PI3K inhibitor (LY294002) or MG132 as indicated for 6 h. Endogenous TAZ protein levels were determined by WB along with the GAPDH control. C, overexpression of AKT increases TAZ protein level in a dose-dependent manner. NIH3T3 cells were transfected with vector or HA-AKT as indicated. Endogenous TAZ protein levels were determined by WB along with β-actin control. β-Catenin was included as a positive control. D, correlation between TAZ protein levels and AKT phosphorylation. Eight breast cancer cell lines and one “normal” breast epithelial cell line (MCF10A) were examined for TAZ protein and AKT phosphorylation.