title: Focal adhesion kinase phosphorylates the phosphatase and tensin homolog deleted on chromosome 10 under the control of p110δ phosphoinositide-3 kinase.
abstract: 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 p110δ 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 from mice expressing kinase-dead p110δ. Pharmacologic inactivation of RhoA/ROCK reduced the phosphorylation of FAK to normal levels in cells with genetically inactivated p110δ. Likewise, pharmacologic inactivation of FAK reduced the phosphorylation of PTEN in cells expressing kinase-dead p110δ and restored the functional defects of p110δ inactivation, including Akt phosphorylation and cell proliferation. This work identifies FAK as a target of p110δ PI3K that links RhoA with PTEN and establishes for the first time that PTEN is a substrate of FAK-mediated Tyr phosphorylation.
authors.affiliation: *Department of Biochemistry, School of Medicine, University of Crete, Vassilika Vouton, Heraklion, Greece; and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece.
authors.forename: Niki
authors.initials: N
authors.lastname: Tzenaki
authors.affiliation: *Department of Biochemistry, School of Medicine, University of Crete, Vassilika Vouton, Heraklion, Greece; and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece.
authors.forename: Michalis
authors.initials: M
authors.lastname: Aivaliotis
authors.affiliation: *Department of Biochemistry, School of Medicine, University of Crete, Vassilika Vouton, Heraklion, Greece; and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece epapak@med.uoc.gr.
authors.forename: Evangelia A
authors.initials: EA
authors.lastname: Papakonstanti
mesh_terms: D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D002879:Chromosomes, Human, Pair 10; D058534:Class I Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D008969:Molecular Sequence Data; D051059:PTEN Phosphohydrolase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation
chemical_list: D058534:Class I Phosphatidylinositol 3-Kinases; C486018:PIK3CD protein, human; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: ROCK; RhoA; tumor suppressor; tyrosine phosphorylation