Abstract

In this chapter we shallreview the physiological role of the prion proteinand its metabolism, withspecial reference to proteases, as well as tothe physiopathological role of abnormal prion protein (termed invarious disorders known as prion diseases or transmissible spongiformencephalopaties (TSEs). In humans TSEs can be classifiedas sporadic, familial and acquired (or infectious). The majority priondiseasein human occurs as sporadic Creutzfeldt-Jakobdisease (sCJD); the familialTSEs include hereditary CJD,Gertsmann-Sträussler-Scheinker disease (GSS)and fatal familial insomnia (FFI), and the acquired include the new variant(vCJD), iatrogenic CJD and kuru. Prions also cause diseases in other species, termed bovinespongiform encephalopathy in cattle, scrapie in sheep and goat. Clinically, these are fatal disorders, characterized by progressivecognitive and neurological impairment withdementia and motor dysfunction. Neuropathological findings include spongiformdegeneration of the brain and sometimes deposition of amyloidplaques,abnormal growth of astrocytes and microglial cells