title: Enniatin has a new function as an inhibitor of Pdr5p, one of the ABC transporters in Saccharomyces cerevisiae.
abstract: Pdr5p is one of the major multidrug efflux pumps whose overexpression confers multidrug resistance (MDR) in Saccharomyces cerevisiae. By using our original assay system, a fungal strain producing inhibitors for Pdr5p was obtained and classified as Fusarium sp. Y-53. The purified inhibitors were identified as ionophore antibiotics, enniatin B, B1, and D, respectively. A non-toxic concentration of each enniatin (5 microg/ml, approximately 7.8 microM) strongly inhibited a Pdr5p-mediated efflux of cycloheximide or cerulenin in Pdr5p-overexpressing cells. The enniatins accumulated a fluorescent dye rhodamine 123, a substrate of Pdr5p, into yeast cells. The mode of Pdr5p inhibition of enniatin was competitive against FK506, and its inhibitory activity was more potent with less toxicity than that of FK506. The enniatins showed similar inhibitory profile as FK506 against S1360 mutants (S1360A and S1360F) of Pdr5p. The enniatins did not inhibit the function of Snq2p, a homologue of Pdr5p. Thus, it was found that enniatins are potent and specific inhibitors for Pdr5p, with less toxicities than that of FK506.
authors.affiliation: Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Hiraga
authors.forename: Shogo
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukuda
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hamanaka
authors.forename: Kohei
authors.initials: K
authors.lastname: Oda
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000187:drug effects / Q000378:metabolism*; D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors* / Q000187:drug effects / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D047630:Depsipeptides / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D008657:Metabolic Clearance Rate; D012441:Saccharomyces cerevisiae / Q000145:classification / Q000187:drug effects* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D047630:Depsipeptides; C092438:PDR5 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C100264:enniatins