TAZ protein level is negatively regulated by PTEN.
A, PTEN is inversely correlated with TAZ stability in breast tumor cell lines. Both BT549 and MDA-MB-453 cells were treated with cycloheximide (CHX) (20 μg/ml) for the indicated times. Endogenous TAZ protein levels were determined. Relative TAZ levels were normalized against β-actin. B, PTEN overexpression decreases TAZ protein level. HA-PTEN was transfected into BT549 for WB analysis. TAZ levels were normalized against β-actin. C, ectopic expression of PTEN in BT549 destabilizes TAZ. HA-PTEN was transfected into BT549 cells, as indicated, and cells were treated with cycloheximide (20 μg/ml) for the indicated times. Endogenous TAZ protein levels were determined. Relative TAZ levels were quantified and normalized against β-actin. D, PTEN knockdown increases TAZ protein. Scramble and shPTEN (purchased from Sigma-Aldrich; clone ID: NM_000314.x-3001s1c1) plasmids were transfected into MDA-MB-231 cells. Protein levels and AKT phosphorylation were determined by Western blotting. Error bars, S.D.