title: Importance of glycolipid synthesis for butyric acid-induced sensitization to shiga toxin and intracellular sorting of toxin in A431 cells.
abstract: The human epidermoid carcinoma cell line A431 becomes highly sensitive to Shiga toxin upon treatment with butyric acid. This strong sensitization (> 1000-fold) is accompanied by an increase in the fraction of cell-associated toxin transported to the Golgi apparatus and to the endoplasmic reticulum (ER). Furthermore, our previous work showed that the length of the fatty acyl chain of Gb3, the Shiga toxin receptor, also was changed (longer fatty acids). We have not investigated the importance of this change by testing whether glycolipid synthesis is required for the changed intracellular sorting and the toxin sensitivity. We demonstrate here that inhibition of glycosphingolipid synthesis by inhibition of N-acyltransferase with fumonisin B1, by inhibition of glucosylceramide synthetase by PDMP or PPMP, or by inhibition of serine palmitoyl transferase by beta-fluoroalanine, inhibited the butyric acid-induced change in sensitivity and the increase in the fraction of cell-associated Shiga toxin transported to the Golgi apparatus and the ER. The block in butyric acid-induced sensitization caused by beta-fluoroalanine could be abolished by simultaneous addition of sphinganine or sphingosine. Thus, the data suggest that the fatty acyl chain length of glycosphingolipids is important for intracellular sorting and translocation of Shiga toxin to the cytosol.
authors.affiliation: Institute for Cancer Research, Norwegian Radium Hospital, Montebello, Oslo, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Sandvig
authors.forename: O
authors.initials: O
authors.lastname: Garred
authors.forename: A
authors.initials: A
authors.lastname: van Helvoort
authors.forename: G
authors.initials: G
authors.lastname: van Meer
authors.forename: B
authors.initials: B
authors.lastname: van Deurs
mesh_terms: D000217:Acyltransferases / Q000037:antagonists & inhibitors; D000409:Alanine / Q000031:analogs & derivatives / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000494:pharmacology; D000963:Antimetabolites / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001427:Bacterial Toxins / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D002087:Butyrates / Q000494:pharmacology*; D020148:Butyric Acid; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D037341:Fumonisins; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors; D006017:Glycolipids / Q000096:biosynthesis* / Q000737:chemistry; D006028:Glycosphingolipids / Q000096:biosynthesis / Q000737:chemistry; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008614:Meperidine / Q000031:analogs & derivatives / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D009183:Mycotoxins / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism; D051102:Serine C-Palmitoyltransferase; D022603:Shiga Toxins; D014407:Tumor Cells, Cultured
chemical_list: D000701:Analgesics, Opioid; D000963:Antimetabolites; D001427:Bacterial Toxins; D002087:Butyrates; D004791:Enzyme Inhibitors; D005227:Fatty Acids; D037341:Fumonisins; D006017:Glycolipids; D006028:Glycosphingolipids; D009025:Morpholines; D009183:Mycotoxins; D011956:Receptors, Cell Surface; D022603:Shiga Toxins; D020148:Butyric Acid; C026733:4-propionyloxy-4-phenyl-N-methylpiperidine; C056933:fumonisin B1; C007742:3-fluoroalanine; C033110:RV 538; D008614:Meperidine; D006735:Horseradish Peroxidase; D000217:Acyltransferases; D051102:Serine C-Palmitoyltransferase; D005964:Glucosyltransferases; C023246:ceramide glucosyltransferase; D000409:Alanine