Prions

Microbiology Overview

Prion Introduction

• A prion is an infective protein 
  • prions are the only known infectious agents that do not contain DNA or RNA
  • when prions infect an organism, they cause normal proteins to misfold and assume the infectious prion form
  • proteins accumulate in the infectious form causing disease
  • proteins remain infectious even after autoclave treatment 
• The prion protein (PrP) is the particular protein that is implicated in all prion diseases
  • normal PrP is denoted PrP^C
  • in prion diseases, PrP is misfolded and denoted PrP^Sc
    • PrP^Sc forms amyloid aggregates containing β-pleated sheets
• Prion diseases 
  • in all prion diseases, the accumulation of PrP^Sc results in
    • spongiform encephalopathy
    • dementia
    • ataxia
    • death
  • Creutzfeldt-Jakob disease 
    • rapidly progressive dementia
    • human form of “mad cow disease” (“variant” CJD)
  • Gerstmann-Sträussler-Scheinker syndrome
    • genetic alteration in PrP
    • inherited
  • kuru
    • cannibalism in Papua New Guinea