Je. Arnold et al., THE ABNORMAL ISOFORM OF THE PRION PROTEIN ACCUMULATES IN LATE-ENDOSOME-LIKE ORGANELLES IN SCRAPIE-INFECTED MOUSE-BRAIN, Journal of pathology, 176(4), 1995, pp. 403-411
The prion encephalopathies are characterized by accumulation in the br
ain of the abnormal form PrPsc of a normal host gene product PrPc. The
mechanism and site of formation of PrPsc from PrPc are currently unkn
own. In this study, ME7 scrapie-infected mouse brain was used to show,
both biochemically and by double-labelled immunogold electron microsc
opy, that proteinase K-resistant PrPsc is enriched in subcellular stru
ctures which contain the cation-independent mannose 6-phosphate recept
or, ubiquitin-protein conjugates, beta-glucuronidase, and cathepsin B,
termed late endosome-like organelles. The glycosylinositol phospholip
id membrane-anchored PrPc will enter such compartments for normal degr
adation and the organelles may therefore act as chambers for the conve
rsion of PrPc into infectious PrPsc in this murine model of scrapie.