title: Functional expression of the multidrug resistance-associated protein in the yeast Saccharomyces cerevisiae.
abstract: The multidrug resistance-associated protein (MRP) is a member of the ATP binding cassette superfamily of transporters which includes the mammalian P-glycoproteins (P-gp) family. In order to facilitate the biochemical and genetic analyses of MRP, we have expressed human MRP in the yeast Saccharomyces cerevisiae and have compared its functional properties to those of the mouse Mdr3 P-gp isoform. Expression of both MRP and Mdr3 in the anthracycline hypersensitive mutant VASY2563 restored cellular resistance to Adriamycin in this mutant. MRP and Mdr3 expression produced pleiotropic effects on drug resistance in this mutant, as corresponding VASY2563 transformants also acquired resistance to the anti-fungal agent FK506 and to the K+/H+ ionophore valinomycin. The appearance of increased cellular resistance to the toxic effect of Adriamycin (ADM) in MRP and Mdr3 transformants was concomitant with a reduced intracellular accumulation of [14C]ADM in spheroplasts prepared from these cells. Moreover, MRP and Mdr3, but not control spheroplasts, could mediate a time-dependent reduction in the overall cell-associated [14C]ADM from preloaded cells, suggesting the presence of an active ADM transport mechanism in MRP and Mdr3 transformants. Finally, human MRP was found to complement the biological activity of the yeast peptide pheromone transporter Ste6 and partially restored mating in a sterile ste6 null mutant. These findings suggest that despite their relatively low level of structural homology, MRP and P-gp share similar functional aspects, since both proteins can mediate transport of chemotherapeutic drugs and the a mating peptide pheromone in yeast.
authors.affiliation: Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Ruetz
authors.forename: M
authors.initials: M
authors.lastname: Brault
authors.forename: C
authors.initials: C
authors.lastname: Kast
authors.forename: C
authors.initials: C
authors.lastname: Hemenway
authors.forename: J
authors.initials: J
authors.lastname: Heitman
authors.forename: C E
authors.initials: CE
authors.lastname: Grant
authors.forename: S P
authors.initials: SP
authors.lastname: Cole
authors.forename: R G
authors.initials: RG
authors.lastname: Deeley
authors.forename: P
authors.initials: P
authors.lastname: Gros
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis*; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis*; D000818:Animals; D004317:Doxorubicin / Q000378:metabolism*; D018432:Drug Resistance, Multiple; D005816:Genetic Complementation Test; D007700:Kinetics; D008322:Mammals; D051379:Mice; D010957:Plasmids; D011994:Recombinant Proteins / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013104:Spheroplasts / Q000378:metabolism; D013997:Time Factors
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018528:ATP-Binding Cassette Transporters; D011994:Recombinant Proteins; D004317:Doxorubicin; C095122:multidrug resistance protein 3