Abstract
The mechanism by which pathogenic mutations in the globular domain of the cellular prion protein (PrP(C)) increase the likelihood of misfolding and predispose to diseases is not yet known. Differences in the evidences provided by structural and metabolic studies of these mutants suggest that in vivo folding could be playing an essential role in their pathogenesis. To address this role, here we use the single or combined M206S and M213S artificial mutants causing labile folds and express them in cells. We find that these mutants are highly toxic, fold as transmembrane PrP, and lack the intramolecular disulfide bond. When the mutations are placed in a chain with impeded transmembrane PrP formation, toxicity is rescued. These results suggest that oxidative folding impairment, as on aging, can be fundamental for the genesis of intracellular neurotoxic intermediates key in prion neurodegenerations.
Highlights
In vivo folding could play an essential role in prion neurodegenerations
As with the HaPrP constructs, we found that the three PrP␣3M mutants induced approximately 40 –50% cell death (Fig. 1C)
The efficient production of secreted PrPC starts with the cotranslational translocation to the ER followed by a series of concerted processing including the cleavage of the N-terminal signal sequence, the addition of glycan chains at two facultative sites, the formation of an intramolecular disulfide bond, and a transamidation at the C terminus to add the GPI moiety [1]
Summary
In vivo folding could play an essential role in prion neurodegenerations. Results: Artificial mutants causing labile PrP folds when expressed in cells originate toxic CtmPrP featured by the absence of the intramolecular disulfide bond. Metabolic studies addressing the effect of pathogenic mutations in the C-terminal domain of PrP as disease predisposition factors have reported a wide range of alterations in processing, trafficking, aggregation, accumulation, and toxicity which varied among experimental setups, as the cell line used and the background expression of wild-type (WT) PrPC [20, 21, 23,24,25,26, 28, 29, 31, 33] These aberrancies contrast with structural reports in which the same pathogenic mutations do not impede the correct in vitro folding, but variably modify the stability, dynamics, and surface reactivity of the native state [12,13,14,15,16, 34, 35]. We found that the PrP␣3M expression is highly toxic and that such toxicity relates to the exclusive formation of CtmPrP due to impeded disulfide bond formation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
