Abstract: Prion protein in an abnormal form of a constituent protein (PrP) of brain cells. It is widely accepted as being the casual agent of a range of fatal neurodegenerative diseases known as prion diseases. Unlike other typical pathogens (bacteria, virus, protozoa etc.) it lacks nucleic acid (DNA, RNA), and this is the novelty of prion concept.
Prions can exist in two different active conformations: the normal harmless brain protein and the aberrant pathogenic protein; having the same primary structure. The normal harmless isoform of prion protein (PrpC ) transforms into an aberrant palthogenic isoform (Pr PSc) during prion disease pathogenesis, and that PrpSc accumulates in the brain neurons and causes neurodegenerative disease. Both prion protein isoforms are encoded by the same prion protein gene (PRNP). Different mutations in the PRNP gene are believed to be responsible for the inherited forms of prion diseases.
Prion diseases are fatal, brain attacking progressive neurodegenerative disorders known as transmissible spongiform encephalopathies in mammals including humans (e.g., mad cow disease, scrapie, Creutzfeldt- Jakob disease, kuru etc). These diseases can be infectious, inherited and sporadic. Apart from typical clinical symptoms there is no definitive diagnosis of prion diseases in living beings. And there is no proven therapy of prion diseases at present. In fact, many things regarding prion protein and associated diseases are still unknown and need further research efforts.