title: Myriocin, an inhibitor of serine palmitoyl transferase, impairs the uptake of transferrin and low-density lipoprotein in mammalian cells.
abstract: The role of sphingolipids in clathrin-mediated endocytosis is only poorly understood in mammalian cells. Thus the relationship between sphingolipid de novo synthesis and clathrin-mediated endocytosis of transferrin were studied in L929 fibroblasts and two other cell lines. Endocytosis was measured using live cell imaging with fluorescent transferrin or (125)I-transferrin. Lipids were primarily measured using electrospray ionization tandem mass spectrometry. At physiological temperature, transferrin uptake was significantly decreased by the inhibitor of serine palmitoyl transferase myriocin. Myriocin inhibited also the uptake of low-density lipoproteins. The endocytosis inhibition by myriocin could be released by the addition of sphingoid base and by the protein phosphorylation effectors phorbol-12-myristate, 13-acetate (PMA) and okadaic acid. Myriocin influenced not only sphingolipids but also the glycerophospholipid profile. The study of phosphatidylcholine species shows adaptations to more saturated, alkylated and longer fatty acid moieties. The reported results imply that in mammalian cells, at 37°C, sphingolipid de novo synthesis is required for clathrin-mediated endocytosis.
authors: Institut für Physiologische Chemie, Universitätsklinikum Essen, Essen, Germany. sybille.meyer@uni-duisburg-essen.de
authors: Sybille G E
authors: SG
authors: Meyer
authors: Agnieszka E
authors: AE
authors: Wendt
authors: Max
authors: M
authors: Scherer
authors: Gerhard
authors: G
authors: Liebisch
authors: Uta
authors: U
authors: Kerkweg
authors: Gerd
authors: G
authors: Schmitz
authors: Herbert
authors: H
authors: de Groot
mesh_terms: D000818:Animals; D002417:Cattle; D002460:Cell Line; D004705:Endocytosis / Q000187:drug effects*; D004734:Energy Metabolism / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology*; D020404:Glycerophospholipids / Q000378:metabolism; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051102:Serine C-Palmitoyltransferase / Q000037:antagonists & inhibitors*; D013107:Sphingolipids / Q000096:biosynthesis; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D005229:Fatty Acids, Monounsaturated; D020404:Glycerophospholipids; D008077:Lipoproteins, LDL; D013107:Sphingolipids; D014168:Transferrin; D051102:Serine C-Palmitoyltransferase; D013110:Sphingosine; C005682:safingol; C001996:thermozymocidin