NR AMXS
AU Zanusso,G.; Petersen,R.B.; Jin,T.; Jing,Y.; Kanoush,R.; Ferrari,S.; Gambetti,P.; Singh,N.
TI Proteasomal degradation and N-terminal protease resistance of the codon 145 mutant prion protein
QU The Journal of Biological Chemistry 1999 Aug 13; 274(33): 23396-404
PT journal article
AB An amber mutation at codon 145 (Y145stop) of the prion protein gene results in a variant of an inherited human prion disease named Gerstmann-Sträussler-Scheinker syndrome. The characteristic features of this disorder include amyloid deposits of prion protein in cerebral parenchyma and vessels. We have studied the biosynthesis and processing of the prion protein containing the Y145stop mutation (PrP(145)) in transfected human neuroblastoma cells in an attempt to clarify the effect of the mutation on the metabolism of PrP(145) and to gain insight into the underlying pathogenetic mechanism. Our results demonstrate that 1) a significant proportion of PrP(145) is not processed post-translationally and retains the N-terminal signal peptide, 2) most PrP(145) is degraded very rapidly by the proteasome-mediated pathway, 3) blockage of proteasomal degradation results in intracellular accumulation of PrP(145), 4) most of the accumulated PrP(145) is detergent-insoluble, and both the detergent-soluble and -insoluble fractions are resistant to mild proteinase K (PK) treatment, suggesting that PK resistance is not simply because of aggregation. The present study demonstrates for the first time that a mutant prion protein is degraded through the proteasomal pathway and acquires PK-resistance if degradation is impaired.
MH Cell Compartmentation; Cell Nucleus/metabolism; *Codon, Terminator; Cysteine Endopeptidases/chemistry/*metabolism; Golgi Apparatus/metabolism; Human; Hydrolysis; Multienzyme Complexes/chemistry/*metabolism; *Mutation; Prions/chemistry/genetics/*metabolism; Protein Isoforms/chemistry/genetics/*metabolism; Support, U.S. Gov't, P.H.S.; Tumor Cells, Cultured
AD Division of Neuropathology, Institute of Pathology, Case Western Reserve University, 2085, Cleveland, Ohio 44106, USA
SP englisch
PO USA