title: The role of PP2A A subunits in tumor suppression.
abstract: The protein phosphatase 2A (PP2A) family of heterotrimeric serine-threonine phosphatases participates in human cell transformation. Each functional PP2A complex contains one structural A subunit (A alpha or A beta), and mutations of both are found to occur at low frequency in human tumors. We have shown that A alpha functions as haploinsufficient tumor suppressor gene by regulating in part phosphatidylinositol 3-kinase (PI3K) signaling. In contrast, loss of A beta function due to biallelic alterations contributes to cancer progression through dysregulation of small GTPase RaIA activity. These observations provide evidence that dysfunction of particular PP2A complexes regulate specific phosphorylation event necessary for cancer initiation.
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusets, USA.
authors.forename: Anna A
authors.initials: AA
authors.lastname: Sablina
authors.forename: William C
authors.initials: WC
authors.lastname: Hahn
mesh_terms: D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D009369:Neoplasms / Q000201:enzymology* / Q000235:genetics; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D054648:Protein Phosphatase 2 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D020725:ral GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D025521:Tumor Suppressor Proteins; D019869:Phosphatidylinositol 3-Kinases; C517189:PPP2CA protein, human; D054648:Protein Phosphatase 2; C492198:RALA protein, human; D020725:ral GTP-Binding Proteins