TY - JOUR
T1 - Characterization of detergent-insoluble complexes containing the cellular prion protein and its scrapie isoform
AU - Naslavsky, Naava
AU - Stein, Ronit
AU - Yanai, Anat
AU - Friedlander, Gilgi
AU - Taraboulos, Albert
PY - 1997/3/7
Y1 - 1997/3/7
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0030894380&partnerID=8YFLogxK
U2 - 10.1074/jbc.272.10.6324
DO - 10.1074/jbc.272.10.6324
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C2 - 9045652
AN - SCOPUS:0030894380
SN - 0021-9258
VL - 272
SP - 6324
EP - 6331
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 10
ER -