Expression of P-glycoprotein, encoded by MDR 1 gene, a metabolically active efflux pump in murine mast cells.
Mast cell line (MC/9) derived from normal murine liver was examined for the expression of P-glycoprotein (P-gp) at the level of protein with C-219 and JSB-1 monoclonal antibodies, using flow cytometry and Western blot, and at the level of mRNA by the reverse transcriptase-polymerase chain reaction. The function of P-gp was analyzed by the accumulation and efflux of rhodamine 123 (Rh123) in the presence or absence of cyclosporin A (CSA) and a non-immunosuppressive analog of CSA (CSA-1). P-gp both at the protein and mRNA levels was expressed in mast cells. Intracellular accumulation of Rh123, in the presence of CSA and CSA-1 was significantly greater than in their absence. Furthermore, both CSA and CSA-1 inhibited Rh123 efflux from mast cells. These data suggest the presence of a functionally active P-gp in mast cells. A possible physiologic role for P-gp in the secretion of certain mediators/cytokines from mast cells is suggested.
Wein
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Division of Basic and Clinical Immunology, Medical Sciences I, University of California, Irvine 92717, USA.
Gupta
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D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000378:metabolism; D001483:Base Sequence; D015153:Blotting, Western; D016572:Cyclosporine / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000235:genetics; D008407:Mast Cells / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012313:RNA / Q000737:chemistry; D020112:Rhodamine 123; D012235:Rhodamines / Q000378:metabolism
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000964:Antimetabolites, Antineoplastic; C034477:RNA primers; D012235:Rhodamines; D020112:Rhodamine 123; D012313:RNA; D016572:Cyclosporine