Proteolytic processing of the prion protein (PrP<superscript>C</superscript>) by endogenous proteases generates bioactive membrane-bound and soluble fragments which may help to explain the pleiotropic roles of this protein in the nervous system and in brain diseases.
Although the discovery of the prion protein (PrP) resulted from its co-purification with scrapie infectivity in Syrian hamsters, work with genetically defined and genetically modified mice proved crucial for understanding the fundamental processes involved not only in prion diseases caused by PrP misfolding, aggregation, and spread but also in other, much more common, neurodegenerative brain diseases.