Most yeast prions (infectious proteins) are amyloids, linear β-sheet-rich polymers of a single protein with the β-strands perpendicular to the long axis of the filament. A single prion protein can form any of many different prion variants, differing in structure and biological properties, but with the same amino acid sequence. The folded parallel β-sheet architecture shown for several yeast prions explains how a given prion variant can be propagated stably, how a protein can template its conformation, just as DNA can template its sequence.
A recent paper in PLoS Pathogens describes an anti-prion system that sequesters prion seeds, preventing their even distribution to daughter cells. The recent discovery of a cellular anti-prion system that cures most arising prions of the yeast Ure2 protein offers a possible direction to look for treatments of amyloidoses such as Alzheimer disease, Parkinson disease, and others. While an array of methods have been found to cure yeast prions by over- or underproduction of various chaperones and other proteins and by various conditions, the system described in this paper cures the [URE3] prion at normal expression levels, indicating that this is a cellular anti-prion system. Information gleaned from yeast systems may have applications in efforts to control human prions and amyloidoses.