title: PtdIns5P protects Akt from dephosphorylation through PP2A inhibition.
abstract: Phosphatidylinositol 5-phosphate (PtdIns5P), the most recently discovered phosphoinositide, has been proposed to play a role as a lipid mediator of intracellular signaling. We have previously shown that PtdIns5P generated by IpgD, an effector of the causative agent of dysentery Shigella flexneri, activates the PI 3-kinase/Akt pathway. Here, we demonstrate that PtdIns5P is able to protect Akt from dephosphorylation. This effect is not due to inhibition of the phosphoinositide phosphatase regulating PtdIns(3,4,5)P(3) levels PTEN but rather to PtdIns5P-induced phosphorylation and subsequent inhibition of the catalytic subunit of PP2A phosphatases. These data shed light on a new mechanism used by S. flexneri bacteria to sustain Akt activation to increase survival of the host cells during bacterial replication.
authors: INSERM U563, Toulouse, France. damien.ramel@inserm.fr
authors: Damien
authors: D
authors: Ramel
authors: Frédéric
authors: F
authors: Lagarrigue
authors: Sophie
authors: S
authors: Dupuis-Coronas
authors: Gaëtan
authors: G
authors: Chicanne
authors: Nicholas
authors: N
authors: Leslie
authors: Frédérique
authors: F
authors: Gaits-Iacovoni
authors: Bernard
authors: B
authors: Payrastre
authors: Hélène
authors: H
authors: Tronchère
mesh_terms: D006367:HeLa Cells; D006801:Humans; D051059:PTEN Phosphohydrolase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism* / Q000494:pharmacology; D010766:Phosphorylation; D054648:Protein Phosphatase 2 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D012763:Shigella flexneri / Q000378:metabolism
chemical_list: D018129:Phosphatidylinositol Phosphates; C113567:phosphatidylinositol 5-phosphate; D051057:Proto-Oncogene Proteins c-akt; D054648:Protein Phosphatase 2; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human