title: ABC transporter Pdr10 regulates the membrane microenvironment of Pdr12 in Saccharomyces cerevisiae.
abstract: The eukaryotic plasma membrane exhibits both asymmetric distribution of lipids between the inner and the outer leaflet and lateral segregation of membrane components within the plane of the bilayer. In budding yeast (Saccharomyces cerevisiae), maintenance of leaflet asymmetry requires P-type ATPases, which are proposed to act as inward-directed lipid translocases (Dnf1, Dnf2, and the associated protein Lem3), and ATP-binding cassette (ABC) transporters, which are proposed to act as outward-directed lipid translocases (Pdr5 and Yor1). The S. cerevisiae genome encodes two other Pdr5-related ABC transporters: Pdr10 (67% identity) and Pdr15 (75% identity). We report the first analysis of Pdr10 localization and function. A Pdr10-GFP chimera was located in discrete puncta in the plasma membrane and was found in the detergent-resistant membrane fraction. Compared to control cells, a pdr10 mutant was resistant to sorbate but hypersensitive to the chitin-binding agent Calcofluor White. Calcofluor sensitivity was attributable to a partial defect in endocytosis of the chitin synthase Chs3, while sorbate resistance was attributable to accumulation of a higher than normal level of the sorbate exporter Pdr12. Epistasis analysis indicated that Pdr10 function requires Pdr5, Pdr12, Lem3, and mature sphingolipids. Strikingly, Pdr12 was shifted to the detergent-resistant membrane fraction in pdr10 cells. Pdr10 therefore acts as a negative regulator for incorporation of Pdr12 into detergent-resistant membranes, a novel role for members of the ABC transporter superfamily.
authors.affiliation: Division of Biochemistry and Molecular Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA. ncrockwell@ucdavis.edu
authors.forename: Nathan C
authors.initials: NC
authors.lastname: Rockwell
authors.forename: Hubert
authors.initials: H
authors.lastname: Wolfger
authors.forename: Karl
authors.initials: K
authors.lastname: Kuchler
authors.forename: Jeremy
authors.initials: J
authors.lastname: Thorner
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D008563:Membrane Lipids; C529225:PDR10 protein, S cerevisiae; C472673:Pdr12 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins