NR ALVI
AU Tzaban,S.; Friedlander,G.; Schonberger,O.; Horonchik,L.; Yedidia,Y.; Shaked,G.; Gabizon,R.; Taraboulos,A.
TI Protease-sensitive scrapie prion protein in aggregates of heterogeneous sizes
QU Biochemistry 2002 Oct 22; 41(42): 12868-75
PT journal article
AB The pathological prion protein PrPsc is the only known component of the infectious prion. In cells infected with prions, PrPsc is formed posttranslationally by the refolding of the benign cell surface glycoprotein PrPc into an aberrant conformation. The two PrP isoforms possess very different properties, as PrPsc has a protease-resistant core, forms very large amyloidic aggregates in detergents, and is only weakly immunoreactive in its native form. We now show that prion-infected rodent brains and cultured cells contain previously unrecognized protease-sensitive PrPsc varieties. In both ionic (Sarkosyl) and nonionic (n-octyl beta-D-glucopyranoside) detergents, the novel protease-sensitive PrPsc species formed aggregates as small as 600 kDa, as measured by gel filtration. The denaturation dependence of PrPsc immunoreactivity correlated with the size of the aggregate. The small PrPsc aggregates described here are consistent with the previous demonstration of scrapie infectivity in brain fractions with a sedimentation coefficient as small as 40 S [Prusiner et al. (1980) J. Neurochem. 35, 574-582]. Our results demonstrate for the first time that prion-infected tissues contain protease-sensitive PrPsc molecules that form low MW aggregates. Whether these new PrPsc species play a role in the biogenesis or the pathogenesis of prions remains to be established.
IN Nicht in den Gehirnen normaler, sondern nur in Hirnhomogenaten mit dem Erregerstamm Sc237 Scrapie-infizierter Hamster sowie ausschließlich in Scrapie-infizierten Mausneuroblastomzelllinien fanden die Autoren ein breites Spektrum ganz unterschiedlich großer Prionprotein-Aggregate. Als proteaseresistent erwiesen sich aber nur die Aggregate, die in einem 10-60% Sucrose-Gradienten bei 200.000-facher Erdbeschleunigung binnen einer Stunde nach einer Sedimentationsbewegung von rund 3 cm den Boden erreichten. Alle kleineren und deshalb langsamer sedimentierenden Aggregate bis hinunter zu Dimeren erwiesen sich als nicht proteaseresistentes PrPsc. Bestätigt wurde dieses Ergebnis durch Ausschluß-Chromatographie. Je kleiner die Aggregate waren, umso stärker ähnelten sie auch in der Hinsicht normalem PrPc, dass ihre Antikörpermarkierbarkeit durch Denaturierung kaum verstärkt wurde. Andererseits sind die PrPsc in den teilweise weniger als 600 kDa kleinen Aggregaten ebenso wie in den großen aminoterminal verkürzt.
MH Animal; Antigen-Antibody Reactions; Brain Chemistry; Cell Fractionation; Cell Line; Chromatography, Gel; Clone Cells; Endopeptidases/*chemistry; Guanidines/chemistry; Hamsters; Hydrolysis; Mesocricetus; Mice; Molecular Weight; PrPsc Proteins/*chemistry/immunology/metabolism; Protein Denaturation; Protein Isoforms/chemistry/immunology/metabolism; Scrapie/metabolism; Support, Non-U.S. Gov't; Thiocyanates/chemistry; Tumor Cells, Cultured
AD Department of Molecular Biology, The Hebrew University-Hadassah Medical School, and Hadassah University Hospital, Jerusalem 91120, Israel.
SP englisch
PO USA