Neuronal pathophysiology featuring PrPC and its control over Ca2+ metabolism.

Calcium (Ca2+) is an intracellular second messenger that ubiquitously masters remarkably diverse biological processes, including cell death. Growing evidence substantiates an involvement of the prion protein (PrPC) in regulating neuronal Ca2+ homeostasis, which could rationalize most of the wide range of functions ascribed to the protein. We have recently demonstrated that PrPC controls extracellular Ca2+ fluxes, and mitochondrial Ca2+ uptake, in neurons stimulated with glutamate (De Mario et al., J Cell Sci 2017; 130:2736-46), suggesting that PrPC protects neurons from threatening Ca2+ overloads and excitotoxicity. In light of these results and of recent reports in the literature, here we review the connection of PrPC with Ca2+ metabolism and also provide some speculative hints on the physiologic outcomes of this link. In addition, because PrPC is implicated in neurodegenerative diseases, including prion disorders and Alzheimer's disease, we will also discuss possible ways by which disruption of PrPC-Ca2+ association could be mechanistically connected with these pathologies.