Prions
Stanley Prusiner proposed in 1982 that scrapie, kuru and similar brain diseases spread by a misfolded protein without genes of its own; mad cow disease made prions a public-health issue.
Open in the interactive tree →Carleton Gajdusek won the 1976 Nobel Prize for showing that kuru could be transmitted to chimpanzees, and in the 1960s Tikvah Alper and John Griffith proposed that such an agent might be protein only. Prusiner coined the word prion in 1982 and received the 1997 Nobel Prize: the normal protein PrP is mostly helical, while the infectious form is rich in sheets and converts normal copies into its own shape. Mad cow disease (BSE) was identified in British cattle in 1986, more than 184,000 cattle were diagnosed up to 2015 and about four million were culled; the human form, variant CJD, was identified in 1996 and about 233 cases had been reported worldwide by 2024. Researchers now study prion-like spreading of misfolded proteins in Alzheimer's and Parkinson's disease.
Prerequisites
- Viruses Discovered1892-1898Scrapie and kuru were first blamed on unusually slow viruses.
- DNA Is the Hereditary Molecule1944A protein-only infectious agent challenged the rule that heredity needs nucleic acid.
Unlocks
- Alzheimer's and Brain DeclineopenSpreading misfolded protein is a leading model of Alzheimer's and Parkinson's progression.