Regulation of trafficking and folding of cellular prion protein PrPC and its shadow Shadoo

Cellular prion protein (PrPC) is a glycosyl-phosphatidyl-inositol (GPI) anchored glycoprotein whose precise function in the brain remains elusive but may depend upon its cellular localization. PrPC is able to misfold to a pathogenic isoform PrPSc, the causative agent of neurodegenerative prion diseases. The PrPSc formation and cellular propagation has been related to the presence of the PrP receptor 37/67 kDa LR (Laminin Receptor), as well as to a member of the prion protein family called Shadoo. The misfolded PrPSc is amyloidogenic and strictly related to expression, intracellular localization and association of PrPC itself to cholesterol enriched membrane microdomains (lipid rafts). In this report we show our recent findings related to: 1. The biological effects deriving from the treatment with specific 37/67 kDa LR inhibitor, NSC47924, on the trafficking and interaction between PrPC and its receptor 2. The natural tendency of Shadoo to acquire in neuronal cells “prion-like” characteristics, such as misfolding and aggregation state, and the existence of its non-translocated ER form, whose presence into mitochondria is controlled by the chaperone TRAP1. Altogether our findings contribute i) to reveal NSC47924 inhibitor as a useful tool to regulate PrPC and 37/67 kDa LR trafficking and degradation, representing a novel small molecule to be tested against prion diseases and ii) to understand the role of molecular chaperones and of PrP-related folding intermediates in “prion-like” conversion.