Prions as adaptive conduits of memory and inheritance

Abstract

Prions are transmissible, self-replicating protein conformations that cause neurodegenerative diseases in mammals, but function as beneficial genetic elements in fungi. The generation of synthetic prions provides definitive support for the prion hypothesis. Beneficial fungal prions are regulated by protein-remodelling factors (such as Hsp104) and molecular chaperones (such as Hsp40). The yeast prion [PSI⁺] confers evolvability and phenotypic plasticity, which impart selective advantages Prions that mimic loss-of-function mutations might act as evolutionary capacitors. Glutamine (Gln)/asparagine (Asn)-rich domains of yeast prions confer all aspects of prion behaviour, and are broadly distributed in many proteins of plants, fungi and metazoa, indicating that prions might be more common than previously thought. CPEB prions might function in the formation of long-term memory. Prions might also be involved in the construction of transcriptional memory and genome-wide expression patterns.