Focal adhesion kinase phosphorylates the phosphatase and tensin homolog deleted on chromosome 10 under the control of p110 delta phosphoinositide-3 kinase

摘要

The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) tumor suppressor protein is regulated by various mechanisms that are not fully understood. This includes regulation by Tyr phosphorylation by a mechanism that remains elusive. Here, we show that focal adhesion kinase (FAK) phosphorylates PTEN in vitro, in cell-free systems and in cells. Furthermore, by mass spectrometry, we identified Tyr336 on PTEN as being phosphorylated by FAK. Tyr336 phosphorylation increased phosphatase activity, protein-lipid interaction, and protein stability of PTEN. In cells, including primary mouse macrophages and human cancer cell lines, FAK was found to be negatively regulated by p110 delta phosphoinositide-3 kinase (PI3K), whereas the activation of FAK was positively regulated by RhoA-associated kinase (ROCK). Indeed, the phosphorylation of FAK was unexpectedly increased in macrophages derived frommice expressing kinase-dead p110 delta. Pharmacologic inactivation of RhoA/ROCK reduced the phosphorylation of FAK to normal levels in cells with genetically inactivated p110 delta. Likewise, pharmacologic inactivation of FAK reduced the phosphorylation of PTEN in cells expressing kinase-dead p110 delta and restored the functional defects of p110 delta inactivation, including Akt phosphorylation and cell proliferation. This work identifies FAK as a target of p110 delta PI3K that links RhoA with PTEN and establishes for the first time that PTEN is a substrate of FAK-mediated Tyr phosphorylation.