Roles of endoproteolytic α-cleavage and shedding of the prion protein in neurodegeneration.

The cellular prion protein (PrP(C)) plays important roles in neurodegenerative diseases. First, it is the well-established substrate for the conformational conversion into its pathogenic isoform (PrP(Sc)) giving rise to progressive and fatal prion diseases. Moreover, several recent reports highlight important roles of PrP(C) in other neurodegenerative conditions such as Alzheimer's disease. Since PrP(C) is subject to proteolytic processing, here we discuss the two main cleavage events under physiological conditions, α-cleavage and shedding. We focus on how these cleavages and the resulting fragments may impact prion diseases as well as other neurodegenerative proteinopathies. Finally, we discuss the recently identified sheddase of PrP(C), namely the metalloprotease ADAM10, with regard to therapeutic potential against neurodegenerative diseases.