Deadly Conformations—Protein Misfolding in Prion Disease

Novel infectious particles, termed prions, composed largely and perhaps solely of a single protein, are the likely causative agents of a group of transmissible spongiform encephalopathies that produce lethal decline of cognitive and motor function. As if the notion of a transmissible pathogenic protein is not jarring enough, evidence indicates that the responsible protein arrives at a pathogenic state by misfolding from a normal form that has ubiquitous tissue distribution. The remarkable nature of these diseases and the nature of the prion protein conversion process as we currently understand it are reviewed below.