title: Phosphoinositide 3-kinase beta protects nuclear envelope integrity by controlling RCC1 localization and Ran activity.
abstract: The nuclear envelope (NE) forms a barrier between the nucleus and the cytosol that preserves genomic integrity. The nuclear lamina and nuclear pore complexes (NPCs) are NE components that regulate nuclear events through interaction with other proteins and DNA. Defects in the nuclear lamina are associated with the development of laminopathies. As cells depleted of phosphoinositide 3-kinase beta (PI3Kβ) showed an aberrant nuclear morphology, we studied the contribution of PI3Kβ to maintenance of NE integrity. pik3cb depletion reduced the nuclear membrane tension, triggered formation of areas of lipid bilayer/lamina discontinuity, and impaired NPC assembly. We show that one mechanism for PI3Kβ regulation of NE/NPC integrity is its association with RCC1 (regulator of chromosome condensation 1), the activator of nuclear Ran GTPase. PI3Kβ controls RCC1 binding to chromatin and, in turn, Ran activation. These findings suggest that PI3Kβ regulates the nuclear envelope through upstream regulation of RCC1 and Ran.
authors.affiliation: Departments of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Redondo-Muñoz
authors.affiliation: Departments of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Pérez-García
authors.affiliation: Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, Spain.
authors.forename: María J
authors.initials: MJ
authors.lastname: Rodríguez
authors.affiliation: Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Valpuesta
authors.affiliation: Departments of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, Spain acarrera@cnb.csic.es.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Carrera
mesh_terms: D000818:Animals; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D058534:Class I Phosphatidylinositol 3-Kinases; D005347:Fibroblasts / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D008051:Lipid Bilayers; D051379:Mice; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D041681:NIH 3T3 Cells; D009685:Nuclear Envelope / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011485:Protein Binding; D020931:ran GTP-Binding Protein / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D002843:Chromatin; D020662:Guanine Nucleotide Exchange Factors; D008051:Lipid Bilayers; D009687:Nuclear Proteins; C062521:RCC1 protein, human; C499302:Rcc1 protein, mouse; D019869:Phosphatidylinositol 3-Kinases; D058534:Class I Phosphatidylinositol 3-Kinases; C497132:PIK3CB protein, human; C546640:Pik3cb protein, mouse; D020931:ran GTP-Binding Protein