Prion disease: a deadly disease for protein misfolding.

An infectious particle, termed prion, composed largely and perhaps solely of a single protein, is the likely causative agent of prion disease. It produces lethal decline of cognitive and motor function. The responsible protein arrives at a pathogenic state by misfolding from a normal form that has ubiquitous tissue distribution. Prion diseases are often called spongiform encephalopathies. Probably most mammalian species develop these diseases. Specific examples in various animals are -Scrapie, Transmissible Mink Encephalopathy (TME ), Chronic Wasting Disease(CWD) and bovine spongiform encephalopathy (BSE). Humans are also susceptible to several prion diseases: Creutzfeld-Jacob Disease (CJD), Gerstmann-Straussler-Scheinker Syndrome (GSS), Fatal Familial Insomnia (FFI), Kuru and Alpers Syndrome. This paper reviews transmission of this diseases, protein involvement, nature of protein, the conversion process from PrP(c) to PrP(Sc), conversion of prion protein in vitro, the different proposed models for the conversion of PrP(c) to PrP(Sc), prion and other amyloid diseases, prion strains, structure of PrP(c) the particular process that may induce prion disease, and immunization against these diseases.