NR ALKM
AU Taraboulos,A.; Rogers,M.; Borchelt,D.R.; McKinley,M.P.; Scott,M.R.D.; Serban,D.; Prusiner,S.B.
TI Acquisition of protease resistance by prion proteins in scrapie-infected cells does not require asparagine-linked glycosylation
QU Proceedings of the National Academy of Sciences of the United States of America 1990 Nov; 87(21): 8262-6
PT journal article
AB The scrapie and cellular isoforms of the prion protein (PrPsc and PrPc) differ strikingly in a number of their biochemical and metabolic properties. The structural features underlying these differences are unknown, but they are thought to result from a posttranslational process. Both PrP isoforms contain complex type oligosaccharides, raising the possibility that differences in the asparagine-linked glycosylation account for the properties that distinguish PrPc and PrPsc. ScN2a and ScHaB cells in culture produce several PrP molecules with relative molecular masses of 26-35 kDa and proteinase K-resistant cores of 19-29 kDa. When the cells were treated with tunicamycin, this heterogeneity was eliminated and a single PrP species of 26 kDa was observed. Several hours after its synthesis, a fraction of this protein became insoluble in detergents and acquired a proteinase K-resistant core, thus displaying two of the biochemical hallmarks of PrPsc. Synthesis in the presence of tunicamycin restricted the proteinase K-resistant cores of PrP to a single species of 19 kDa. No proteinase K-resistant PrP was found in uninfected cells. Expression of a mutated PrP gene lacking both asparagine-linked glycosylation sites in ScN2a cells resulted in the synthesis of 19-kDa proteinase K-resistant PrP molecules. We conclude that asparagine-linked glycosylation is not essential for the synthesis of proteinase K-resistant PrP and that structural differences unrelated to asparagine-linked oligosaccharides must exist between PrPc and PrPsc. Whether unglycosylated PrPsc molecules are associated with scrapie prion infectivity remains to be established.
MH Amino Acid Sequence; Asparagine; *Cell Transformation, Viral; Endopeptidase K; Glycosylation; Kinetics; Molecular Sequence Data; PrPsc Proteins; Prions/*genetics; Protein Processing, Post-Translational/drug effects; Serine Endopeptidases/*metabolism; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.; Tunicamycin/pharmacology; Viral Proteins/*genetics/isolation & purification/metabolism
AD Department of Neurology, University of California, San Francisco 94143.
SP englisch
PO USA