NR APVH
AU Parkin,E.T.; Watt,N.T.; Turner,A.J.; Hooper,N.M.
TI Dual mechanisms for shedding of the cellular prion protein
QU The Journal of Biological Chemistry 2004 Mar 19; 279(12): 11170-8
PT journal article
AB The cellular prion protein (PrPc) is essential for the pathogenesis and transmission of prion diseases. Whereas the majority of PrPc is bound to the cell membrane via a glycosylphosphatidylinositol (GPI) anchor, a secreted form of the protein has been identified. Here we show that PrPc can be shed into the medium of human neuroblastoma SH-SY5Y cells by both protease- and phospholipase-mediated mechanisms. The constitutive shedding of PrPc was inhibited by a range of hydroxamate-based zinc metalloprotease inhibitors in a manner identical to the alpha-secretase-mediated shedding of the amyloid precursor protein, indicating a proteolytic shedding mechanism. Like amyloid precursor protein, this zinc metalloprotease-mediated shedding of PrPc could be stimulated by phorbol myristate acetate and by copper ions. The lipid raft-disrupting agents filipin and methyl-beta-cyclodextrin promoted the shedding of PrPc via a distinct mechanism that was not inhibited by hydroxamate-based inhibitors. Filipin-mediated shedding of PrPc is likely to occur via phospholipase cleavage of the GPI anchor, since a transmembrane polypeptide-anchored PrP construct was not shed in response to filipin treatment. Collectively, our data indicate that shedding of PrPc can occur via both secretase-like proteolytic cleavage of the protein and phospholipase cleavage of the GPI anchor moiety.
MH Cell Line, Tumor; Electrophoresis, Polyacrylamide Gel; Filipin/metabolism; Glycosylphosphatidylinositols/metabolism; Human; Phosphatidylinositol Diacylglycerol-Lyase/metabolism; PrPc Proteins/*metabolism; Support, Non-U.S. Gov't
AD Proteolysis Research Group, School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
SP englisch
PO USA