Sphingolipid depletion increases formation of the scrapie prion protein in neuroblastoma cells infected with prions

Naava Naslavsky, Hilary Shmeeda, Gilgi Friedlander, Anat Yanai, Anthony H. Futerman, Yechezkel Barenholz, Albert Taraboulos

Research output: Contribution to journalArticlepeer-review

151 Scopus citations

Abstract

Sphingolipid-rich rafts play an essential role in the posttranslational (Borchelt, D. R., Scott, M., Taraboulos, A., Stahl, N., and Prusiner, S. B. (1990) J. Cell Biol. 110, 743-752)) formation of the scrapie prion protein PrP(Sc) from its normal conformer PrP(c) (Taraboulos, A., Scott, M., Semenov, A., Avrahami, D., Laszlo, L., Prusiner, S. B., and Avraham, D. (1995) J. Cell Biol. 129, 121-132). We investigated the importance of sphingolipids in the metabolism of the PrP isoforms in scrapie-infected ScN2a cells. The ceramide synthase inhibitor fumonisin B1 (FB1) reduced both sphingomyelin (SM) and ganglioside GM1 in cells by up to 50%, whereas PrP(Sc) increased by 3-4- fold. Whereas FB1 profoundly altered the cell lipid composition, the raft residents PrP(c), PrP(Sc), caveolin 1, and GM1 remained insoluble in Triton X-100. Metabolic radiolabeling demonstrated that PrP(c) production was either unchanged or slightly reduced in FB1-treated cells, whereas PrP(Sc) formation was augmented by 3-4-fold. To identify the sphingolipid species the decrease of which correlates with increased PrP(Sc), we used two other reagents. When cells were incubated with sphingomyelinase for 3 days, SM levels decreased, GM1 was unaltered, and PrP(Sc) increased by 3-4-fold. In contrast, the glycosphingolipid inhibitor PDMP reduced PrP(Sc) while increasing SM. Thus, PrP(Sc) seems to correlate inversely with SM levels. The effects of SM depletion contrasted with those previously obtained with the cholesterol inhibitor lovastatin, which reduced PrP(Sc) and removed it from detergent-insoluble complexes.

Original languageEnglish (US)
Pages (from-to)20763-20771
Number of pages9
JournalJournal of Biological Chemistry
Volume274
Issue number30
DOIs
StatePublished - Jul 23 1999

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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