Fig. 2
From: The biological function of the cellular prion protein: an update
PrPC exerts its functions via distinct mechanisms. The cellular prion protein may utilize several mechanisms to modulate cellular functions. As schematically depicted in a, PrPC may directly alter the function of its target protein by mediating posttranslational modifications, for example, by promoting the S-nitrosylation of the NMDA receptor. Alternatively, PrPC modulates auxiliary proteins of ion channels, thereby regulating the biophysical properties of the channel (b) or its trafficking (c). Another function of PrPC arises from its ability to bind divalent cations such as zinc (Zn2+) or copper (Cu2+). It was claimed that PrPC may buffer these cations within the synaptic cleft and may facilitate their uptake (d) via AMPA receptors. Some better-defined actions of PrPC include its binding to misfolded oligomeric protein species and signaling in complex with other membrane receptors (e). Additionally, PrPC can signal in trans by its N-terminal cleavage products, which may bind to other receptors, prominently including the G-protein-coupled receptor Adgrg6 (f)