C-tail hyperphosphorylation activates PTEN oncogenic properties

PTEN is a multifaceted tumor suppressor that is highly sensitive to alterations in expression or function. The PTEN C-tail domain, which is rich in phosphorylation sites, has been implicated in PTEN stability, localization, catalytic activity, and protein interactions, but its role in tumor suppression remains unknown. To address this, we utilized several mouse strains with nonlethal C-tail mutations. Analysis of mice containing nonphosphorylatable or phosphomimetic versions of S380, a C-tail residue hyperphosphorylated in human gastric cancers, reveals that PTEN stability and ability to inhibit PI3K-AKT depends on dynamic phosphorylation-dephosphorylation of this residue. While phosphomimetic S380 drives neoplastic growth in prostate by promoting nuclear accumulation of β-catenin, nonphosphorylatable S380 is not tumorigenic. These data suggest that C-tail hyper-phosphorylation creates oncogenic PTEN and is a potential target for anti-cancer therapy. 3 prostates of each genotype: WT, Pten S380A/S380A and Pten S380D/S380D