title: Interaction between protein phosphatase 2A and members of the importin beta superfamily.
abstract: While performing a yeast two-hybrid library screen to uncover novel PP2A-interacting proteins, we discovered a specific interaction between a member of the importin beta/karyopherin beta superfamily, importin 9, and the A subunit of PP2A (PR65). This interaction between importin 9 and the A subunit was confirmed by in vitro pulldown, immunoprecipitation, and microcystin-Sepharose chromatography. We also found that another family member, importin beta, interacted specifically with the A subunit of PP2A. Finally, we showed that treatment of cells with a concentration of okadaic acid known to inhibit PP2A impeded the nuclear localization of an NLS-containing protein. These results provide evidence that these importins can exist in a native complex with endogenous PP2A and that this serine/threonine phosphatase plays a role in regulating the nuclear import of NLS-containing proteins in vivo.
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Chandler Medical Center, 800 Rose Street, Lexington, KY 40536-0298, USA.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Lubert
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Sarge
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D001665:Binding Sites; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D019913:Nuclear Localization Signals / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019319:Okadaic Acid / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054648:Protein Phosphatase 2; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D028961:beta Karyopherins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D019913:Nuclear Localization Signals; C432785:PPP2R1B protein, human; C086766:Ppp2r1b protein, mouse; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D028961:beta Karyopherins; C571727:importin 9, mouse; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2