PRNP and scrapie: The endogenous prion protein (PrPC, for cellular PrP), a glycosylphosphatidylinositol-anchored cell surface protein that is highly abundant in the peripheral and central nervous systems (PNS and CNS, respectively), undergoes conformational changes from its native α-helical structure to its pathogenic, β-sheet rich conformation (PrPSc, for PrP scrapie) [51,52,53].