ABC Transporter Pdr10 Regulates the Membrane Microenvironment of Pdr12 in <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> |
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Authors: | Nathan C Rockwell Hubert Wolfger Karl Kuchler Jeremy Thorner |
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Institution: | (1) Division of Biochemistry and Molecular Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA;(2) Present address: c/o Lagarias Lab, Department of Molecular and Cellular Biology, University of California, 31 Briggs Hall, Davis, CA 95616, USA;(3) Max F. Perutz Laboratories, Medical University of Vienna, 1030 Vienna, Austria;(4) Department of Molecular and Cell Biology, University of California, Room 16, Barker Hall, Berkeley, CA 94720-3202, USA |
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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. |
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Keywords: | Pdr10 ABC transporter Sphingolipid Lipid raft Detergent-resistant membrane Lateral segregation Pdr12 Lem3 Dnf1 Dnf2 |
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