Role of PrPc Related to Apoptosis

Abstract

Prion diseases are transmissible neurodegenerative disorders that are invariably fatal in human and animals. Although the nature of the infectious agent and pathogenic mechanisms of prion diseases are not clear, it has been reported to be associated with aberrant metabolism of cellular prion protein (PrPc). In various reports, it has been postulated that PrPc may be involved in programmed cell death or apoptosis. Apoptosis of neuronal cells can also be induced in vitro by exposure to PrPsc or a neurotoxic peptide fragment corresponding to amino acids 106-126,118-135 of human prion protein (PrP106-126;PrP118-135). While the anti-apoptotic and anti-oxidative function of PrPc is regulated by not only OR (Octapeptide Region,amino acid residue 51-91) but also the N-terminal half of HR(Hydrophobic Region, amino acids residue 95-132). PrPc may participate in apoptosis through extrinsic pathway by binding to certain chaperon molecules or through induced by certain stresses like inflammatory factors. It can also by modulating Bcl-2/Bax, endogenous dismutase activity and calcium channel, control the activation and translocation of the mitochondria which leads to apoptosis involving certain effective molecules of caspase family. Meanwhile above biological events would be controlled by cAMP/APK, p38/MAPK, JNK, p53, NF-?B pathways et al. Further understanding of the apoptosis in PrPc have important implications for designing therapy of prion diseases, as well as for understanding pathogenic mechanisms operative in other neurodegenerative disorders and the role of prion in biology.