Pulling rabbits to reveal the secrets of the prion protein.

The Prion protein (PrP) is a membrane-tethered glycoprotein that plays a central role in a unique class of neurodegenerative diseases that affect humans and other mammals. Prion diseases have genetic and sporadic origins, but their infectious nature sets them apart from other neurodegenerative disorders. According to the "protein-only" hypothesis, misfolded PrP conformers (prions) are responsible for both spongiform degeneration of the brain and disease transmissibility. Thus, understanding PrP conformational dynamics is key to developing effective therapies. Classic studies showing the different susceptibility to prion disease in mammals have recently found support in structural and transgenic studies with PrP from susceptible (mouse, hamster) and resistant (rabbit, horse, dog) animals. These studies identify key residues in PrP that determine both PrP structure and its propensity to acquire a β-structure conformation proposed to be neurotoxic.