Pathway complexity of prion protein assembly into amyloid

J Biol Chem. 2002 Jun 14;277(24):21140-8. doi: 10.1074/jbc.M111402200. Epub 2002 Mar 23.

Abstract

In vivo under pathological conditions, the normal cellular form of the prion protein, PrP(C) (residues 23-231), misfolds to the pathogenic isoform PrP(Sc), a beta-rich aggregated pathogenic multimer. Proteinase K digestion of PrP(Sc) leads to a proteolytically resistant core, PrP 27-30 (residues 90-231), that can form amyloid fibrils. To study the kinetic pathways of amyloid formation in vitro, we used unglycosylated recombinant PrP corresponding to the proteinase K-resistant core of PrP(Sc) and found that it can adopt two non-native abnormal isoforms, a beta-oligomer and an amyloid fibril. Several lines of kinetic data suggest that the beta-oligomer is not on the pathway to amyloid formation. The preferences for forming either a beta-oligomer or amyloid can be dictated by experimental conditions, with acidic pH similar to that seen in endocytic vesicles favoring the beta-oligomer and neutral pH favoring amyloid. Although both abnormal isoforms have high beta-sheet content and bind 1-anilinonaphthalene-8-sulfonate, they are dissimilar structurally. Multiple pathways of misfolding and the formation of distinct beta-sheet-rich abnormal isoforms may explain the difficulties in refolding PrP(Sc) in vitro, the need for a PrP(Sc) template, and the significant variation in disease presentation and neuropathology.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amyloid / chemistry*
  • Anilino Naphthalenesulfonates / pharmacology
  • Animals
  • Chromatography, High Pressure Liquid
  • Circular Dichroism
  • Cricetinae
  • Dimerization
  • Dose-Response Relationship, Drug
  • Endopeptidase K / pharmacology
  • Epitopes
  • Fluorescent Dyes / pharmacology
  • Hydrogen-Ion Concentration
  • Kinetics
  • Light
  • Mass Spectrometry
  • Mesocricetus
  • Mice
  • Microscopy, Electron
  • Prions / chemistry*
  • Prions / metabolism*
  • Protein Binding
  • Protein Conformation
  • Protein Folding
  • Protein Isoforms
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Recombinant Proteins / chemistry
  • Scattering, Radiation
  • Time Factors

Substances

  • Amyloid
  • Anilino Naphthalenesulfonates
  • Epitopes
  • Fluorescent Dyes
  • Prions
  • Protein Isoforms
  • Recombinant Proteins
  • 1-anilino-8-naphthalenesulfonate
  • Endopeptidase K