Its primary physiological function is unclear. May play a role in neuronal development and synaptic plasticity. May be required for neuronal myelin sheath maintenance. May promote myelin homeostasis through acting as an agonist for ADGRG6 receptor. May play a role in iron uptake and iron homeostasis. Soluble oligomers are toxic to cultured neuroblastoma cells and induce apoptosis (in vitro) (By similarity). Association with GPC1 (via its heparan sulfate chains) targets PRNP to lipid rafts. Also provides Cu(2+) or Zn(2+) for the ascorbate-mediated GPC1 deaminase degradation of its heparan sulfate side chains (By similarity). Monomer and homodimer. Has a tendency to aggregate into amyloid fibrils containing a cross-beta spine, formed by a steric zipper of superposed beta-strands. Soluble oligomers may represent an intermediate stage on the path to fibril formation. Copper binding may promote oligomerization. Interacts with GRB2, APP, ERI3/PRNPIP and SYN1 (By similarity). Mislocalized cytosolically exposed PrP interacts with MGRN1; this interaction alters MGRN1 subcellular location and causes lysosomal enlargement (By similarity). Interacts with APP. Interacts with KIAA1191 (By similarity). Interacts with ADGRG6 (By similarity). Targeted to lipid rafts via association with the heparan sulfate chains of GPC1. Colocates, in the presence of Cu(2+), to vesicles in para- and perinuclear regions, where both proteins undergo internalization. Heparin displaces PRNP from lipid rafts and promotes endocytosis. The normal, monomeric form has a mainly alpha-helical structure. The disease-associated, protease-resistant form forms amyloid fibrils containing a cross-beta spine, formed by a steric zipper of superposed beta-strands. Disease mutations may favor intermolecular contacts via short beta strands, and may thereby trigger oligomerization. Contains an N-terminal region composed of octamer repeats. At low copper concentrations, the sidechains of His residues from three or four repeats contribute to the binding of a single copper ion. Alternatively, a copper ion can be bound by interaction with the sidechain and backbone amide nitrogen of a single His residue. The observed copper binding stoichiometry suggests that two repeat regions cooperate to stabilize the binding of a single copper ion. At higher copper concentrations, each octamer can bind one copper ion by interactions with the His sidechain and Gly backbone atoms. A mixture of binding types may occur, especially in the case of octamer repeat expansion. Copper binding may stabilize the conformation of this region and may promote oligomerization. Variations in PRNP are responsible of transmissible bovine spongiform encephalopathies (BSE), a class of neurodegenerative diseases that affect various mammals. These diseases are caused by abnormally folded prion proteins. BSE can be subdivided into at least three groups: classical, H-type and L-type, with the latter 2 collectively referred to as atypical BSE. Susceptibility or resistance to a BSE disease can be influenced by at least 3 factors related to the host prion protein: protein expression levels, number of octapeptide repeats, and specific polymorphisms. In cattle, as in humans, BSEs can occur as infectious, spontaneous and genetic diseases. The heritable variant Lys-211 can be the cause of genetic late onset H-type BSE. Belongs to the prion family.