Cell-free formation of protease-resistant prion protein

Protease-sensitive prion protein (PrPc) can be converted to protease-resistant forms that are analogous to scrapie-associated prion protein (PrPSc) in a cell-free system that contains purified components. This conversion is preferential and needs the presence of preexisting PrPSc, proving that PrPSc is obtained from specific PrPc-PrPSc interactions. The PrPSc formation mechanism is central in the transmissible spongiform encephalopathies pathogenesis.