Heritable activity: a prion that propagates by covalent autoactivation.
Known prions (infectious proteins) are self-propagating amyloids or conformationally altered proteins, but in theory an enzyme necessary for its own activation could also be a prion (or a gene composed of protein). We show that yeast protease B is such a prion, called [beta].[beta] is infectious, reversibly curable, and its de novo generation is induced by overexpression of the pro-protease. Present in normal cells but masked by the functionally redundant protease A, [beta] is advantageous during starvation and necessary for sporulation. We propose that other enzymes whose active, modified, form is necessary for their maturation might also be prions.
Roberts
B Tibor
BT
Laboratory of Biochemistry and Genetics, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA.
Wickner
Reed B
RB
D010450:Endopeptidases / Q000378:metabolism*; D010641:Phenotype; D011328:Prions / Q000096:biosynthesis / Q000378:metabolism*; D015003:Yeasts / Q000378:metabolism*
D011328:Prions; D010450:Endopeptidases