| Type: | Repeat | Name: | Prion, copper binding octapeptide repeat |
| Description: | Prion protein (PrP-c) [, , ] is a small glycoprotein found in high quantity in the brain of animals infected with certain degenerative neurological diseases, such as sheep scrapie and bovine spongiform encephalopathy (BSE), and the human dementias Creutzfeldt-Jacob disease (CJD) and Gerstmann-Straussler syndrome (GSS). PrP-c is encoded in the host genome and is expressed both in normal and infected cells. During infection, however, the PrP-c molecule become altered (conformationally rather than at the amino acid level) to an abnormal isoform, PrP-sc. In detergent-treated brain extracts from infected individuals, fibrilscomposed of polymers of PrP-sc, namely scrapie-associated fibrils or prion rods, can be evidenced by electron microscopy. The precise function of the normal PrP isoform in healthy individuals remains unknown. Several results, mainly obtained in transgenic animals, indicate that PrP-c might play a role in long-term potentiation, in sleep physiology, in oxidative burst compensation (PrP can fix four Cu2+ through its octarepeat domain), ininteractions with the extracellular matrix (PrP-c can bind to the precursor of the laminin receptor, LRP), in apoptosis and in signal transduction (costimulation of PrP-c induces a modulation of Fyn kinase phosphorylation) [].The normal isoform, PrP-c, is anchored at the cell membrane, in rafts, through a glycosyl phosphatidyl inositol (GPI); its half-life at the cell surface is 5 h, after which the protein is internalised through a caveolae-dependent mechanism and degraded in the endolysosome compartment. Conversion between PrP-c and PrP-scoccurs likely during the internalisation process. This repeat is found at the amino terminus of mammalian prion proteins. It has been shown to bind to copper []. | Short Name: | Prion_copper_b_octapeptide |
