Characterization of detergent-insoluble complexes containing the cellular prion protein and its scrapie isoform

Naava Naslavsky, Ronit Stein, Anat Yanai, Gilgi Friedlander, Albert Taraboulos*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

357 Scopus citations

Abstract

Cells infected with prions contain both prion protein isoforms cellular prion protein (PrP(c)) and scrapie prion protein (PrP(Sc)). PrP(Sc) is formed posttranslationally through the pathological refolding of PrP(C). In scrapie- infected ScN2a cells, the metabolism of both PrP isoforms involves cholesterol-dependent pathways. We show here that both PrP(C) and PrP(Sc) are attached to Triton X-100-insoluble, low-density complexes or 'rafts.' These complexes are sensitive to saponin and thus probably contain cholesterol. This finding suggests that the transformation PrP(C) → PrP(Sc) occurs within rafts. It also reveals the existence of rafts in late compartments of the endocytic pathway, where most PrP(Sc) resides. When Triton X-100 lysates of cells were incubated at 37°C prior to density analysis, PrP(C) was still found in buoyant complexes, although it now failed to sediment at high speed. This property was shared by another glycophosphatidyl inositol protein, Thy- 1, and also by the raft resident GM1. In one ScN2a clone and in the brain of a Syrian hamster with scrapie, Triton X-100 extraction at 37 °C permitted resolution of PrP(C) and PrP(Sc) into two distinct peaks of different densities. This suggests that there are two populations of PrP-containing rafts and may permit isolation of FrP(C)-specific rafts from those containing PrP(Sc). Our findings reinforce the contention that rafts are involved in various aspects of PrP metabolism and in the 'life cycle' of prions.

Original languageEnglish
Pages (from-to)6324-6331
Number of pages8
JournalJournal of Biological Chemistry
Volume272
Issue number10
DOIs
StatePublished - 7 Mar 1997

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