title: Localization of P-glycoprotein at the nuclear envelope of rat brain cells.
abstract: P-glycoprotein is a plasma membrane drug efflux protein implicated in extrusion of cytotoxic compounds out of a cell. There is now evidence that suggests expression of this transporter at several subcellular sites, including the nucleus, mitochondria, and Golgi apparatus. This study investigated the localization and expression of P-glycoprotein at the nuclear membrane of rat brain microvessel endothelial (RBE4) and microglial (MLS-9) cell lines. Immunocytochemistry at the light and electron microscope levels using P-glycoprotein monoclonals antibodies demonstrated the localization of the protein at the nuclear envelope of RBE4 and MLS-9 cells. Western blot analysis revealed a single band of 170-kDa in purified nuclear membranes prepared from isolated nuclei of RBE4 and MLS-9 cells. These findings indicate that P-glycoprotein is expressed at the nuclear envelope of rat brain cells and suggest a role in multidrug resistance at this subcellular site.
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ont., Canada M5S 3M2.
authors.forename: Karlo
authors.initials: K
authors.lastname: Babakhanian
authors.forename: Moise
authors.initials: M
authors.lastname: Bendayan
authors.forename: Reina
authors.initials: R
authors.lastname: Bendayan
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000166:cytology* / Q000378:metabolism*; D002460:Cell Line; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D017628:Microglia / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D009685:Nuclear Envelope / Q000378:metabolism* / Q000648:ultrastructure; D021381:Protein Transport; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1