MDR1 P-glycoprotein is a lipid translocase of broad specificity, while MDR3 P-glycoprotein specifically translocates phosphatidylcholine
Article Abstract:
Human MDR1 and mouse mdr1a cDNA were transfected into LLC-PK1 pig kidney epithelial cells to investigate the translocation of MDR1 and MDR3 P-glycoproteins (Pgp) across the plasma membrane. Lipid analysis at 15 degrees centigrade showed that MDR1 cells released short-chaine membrane lipids to the apical membrane but not in control cells. The addition of MDR inhibitors and energy depletion prevented lipid release from MDR1 cells but MDR3 cells showed continuous release of short-chain phosphatidylcholine. Failure to detect lipids at the vesicles indicated that the lipids have already been translocated across the plasma membrane.
Publication Name: Cell
Subject: Biological sciences
ISSN: 0092-8674
Year: 1996
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Inversion of the membrane topology of SecG coupled with SecA-dependent preprotein translocation
Article Abstract:
A study of preprotein translocation across the cytoplasmic membrane showed the roles and conformational changes undergone by the protein translocases SecA and the SecY/E/G complex. SecA identifies the preprotein and carries it to the conducting channel formed by SecY/E. SecG translocase undergoes topology inversion to allow the preprotein to pass through the everted membrane vesicles. SecG's topological inversion is linked with the insertion and deinsertion cycle of SecA. SecG's topological inversion is effected by ATP binding and hydrolysis.
Publication Name: Cell
Subject: Biological sciences
ISSN: 0092-8674
Year: 1996
User Contributions:
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