Document Detail

Role of multiple drug resistance protein 1 in neutral but not acidic glycosphingolipid biosynthesis.
MedLine Citation:
PMID:  14662772     Owner:  NLM     Status:  MEDLINE    
Transfection studies have implicated the multiple drug resistance pump, MDR1, as a glucosyl ceramide translocase within the Golgi complex (Lala, P., Ito, S., and Lingwood, C. A. (2000) J. Biol. Chem. 275, 6246-6251). We now show that MDR1 inhibitors, cyclosporin A or ketoconazole, inhibit neutral glycosphingolipid biosynthesis in 11 of 12 cell lines tested. The exception, HeLa cells, do not express MDR1. Microsomal lactosyl ceramide and globotriaosyl ceramide synthesis from endogenous or exogenously added liposomal glucosyl ceramide was inhibited by cyclosporin A, consistent with a direct role for MDR1/glucosyl ceramide translocase activity in their synthesis. In contrast, cellular ganglioside synthesis in the same cells, was unaffected by MDR1 inhibition, suggesting neutral and acid glycosphingolipids are synthesized from distinct precursor glycosphingolipid pools. Metabolic labeling in wild type and knock-out (MDR1a, 1b, MRP1) mouse fibroblasts showed the same loss of neutral glycosphingolipid (glucosyl ceramide, lactosyl ceramide) but not ganglioside (GM3) synthesis, confirming the proposed role for MDR1 translocase activity. Cryo-immunoelectron microscopy showed MDR1 was predominantly intracellular, largely in rab6-containing Golgi vesicles and Golgi cisternae, the site of glycosphingolipid synthesis. These studies identify MDR1 as the major glucosyl ceramide flippase required for neutral glycosphingolipid anabolism and demonstrate a previously unappreciated dichotomy between neutral and acid glycosphingolipid synthesis.
María Fabiana De Rosa; Daniel Sillence; Cameron Ackerley; Clifford Lingwood
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2003-12-08
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  279     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2004 Feb 
Date Detail:
Created Date:  2004-02-23     Completed Date:  2004-05-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  7867-76     Citation Subset:  IM    
Research Institute and Department of Pediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada.
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MeSH Terms
Acidic Glycosphingolipids / biosynthesis*
Carrier Proteins / metabolism
Cell Line
Cyclosporine / pharmacology
Gene Expression
Glucosylceramides / metabolism
Hela Cells
Ketoconazole / pharmacology
Lactosylceramides / biosynthesis
Membrane Proteins / metabolism
Mice, Knockout
Microscopy, Immunoelectron
Neutral Glycosphingolipids / biosynthesis*
P-Glycoprotein / antagonists & inhibitors,  genetics,  physiology*
Phospholipid Transfer Proteins*
Recombinant Proteins
Trihexosylceramides / biosynthesis
Tumor Cells, Cultured
Reg. No./Substance:
0/Acidic Glycosphingolipids; 0/Carrier Proteins; 0/Glucosylceramides; 0/Lactosylceramides; 0/Membrane Proteins; 0/Neutral Glycosphingolipids; 0/P-Glycoprotein; 0/Phospholipid Transfer Proteins; 0/Recombinant Proteins; 0/Trihexosylceramides; 59865-13-3/Cyclosporine; 65277-42-1/Ketoconazole; 71965-57-6/globotriaosylceramide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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