Control of Plasma Membrane Permeability by ABC Transporters.
ATP-binding cassette transporters Pdr5 and Yor1 from Saccharomyces cerevisiae control the asymmetric distribution of phospholipids across the plasma membrane as well as serving as ATP-dependent drug efflux pumps. Mutant strains lacking these transporter proteins were found to exhibit very different resistance phenotypes to two inhibitors of sphingolipid biosynthesis that act either late (aureobasidin A [AbA]) or early (myriocin [Myr]) in the pathway leading to production of these important plasma membrane lipids. These pdr5Δ yor1 strains were highly AbA resistant but extremely sensitive to Myr. We provide evidence that these phenotypic changes are likely due to modulation of the plasma membrane flippase complexes, Dnf1/Lem3 and Dnf2/Lem3. Flippases act to move phospholipids from the outer to the inner leaflet of the plasma membrane. Genetic analyses indicate that lem3Δ mutant strains are highly AbA sensitive and Myr resistant. These phenotypes are fully epistatic to those seen in pdr5Δ yor1 strains. Direct analysis of AbA-induced signaling demonstrated that loss of Pdr5 and Yor1 inhibited the AbA-triggered phosphorylation of the AGC kinase Ypk1 and its substrate Orm1. Microarray experiments found that a pdr5Δ yor1 strain induced a Pdr1-dependent induction of the entire Pdr regulon. Our data support the view that Pdr5/Yor1 negatively regulate flippase function and activity of the nuclear Pdr1 transcription factor. Together, these data argue that the interaction of the ABC transporters Pdr5 and Yor1 with the Lem3-dependent flippases regulates permeability of AbA via control of plasma membrane protein function as seen for the high-affinity tryptophan permease Tat2.
Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
Svetlana
S
Khakhina
Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
Soraya S
SS
Johnson
Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
Raman
R
Manoharlal
Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA.
Sarah B
SB
Russo
École Normale Supérieure, Institut de Biologie de l'ENS, IBENS, Paris, France INSERM, U1024, Paris, France CNRS, UMR 8197, Paris, France.
Corinne
C
Blugeon
École Normale Supérieure, Institut de Biologie de l'ENS, IBENS, Paris, France INSERM, U1024, Paris, France CNRS, UMR 8197, Paris, France.
Sophie
S
Lemoine
Department of Genome Sciences, University of Washington, Seattle, Washington, USA.
Anna B
AB
Sunshine
Department of Genome Sciences, University of Washington, Seattle, Washington, USA.
Maitreya J
MJ
Dunham
Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA.
L Ashley
LA
Cowart
Sorbonne Universités, UPMC Universite Paris 06, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France CNRS, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France.
Frédéric
F
Devaux
Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA scott-moye-rowley@uiowa.edu.
W Scott
WS
Moye-Rowley
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D018528:ATP-Binding Cassette Transporters; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors