Lipid Rafts and Clathrin Cooperate in the Internalization of PrPC in Epithelial FRT CellsReportar como inadecuado

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The cellular prion protein PrPC plays a key role in the pathogenesis of Transmissible Spongiform Encephalopathies in which the protein undergoes post-translational conversion to the infectious form PrPSc. Although endocytosis appears to be required for this conversion, the mechanism of PrPC internalization is still debated, as caveolae-raft- and clathrin-dependent processes have all been reported to be involved.

Methodology-Principal Findings

We have investigated the mechanism of PrPC endocytosis in Fischer Rat Thyroid FRT cells, which lack caveolin-1 cav-1 and caveolae, and in FRT-cav-1 cells which form functional caveolae. We show that PrPC internalization requires activated Cdc-42 and is sensitive to cholesterol depletion but not to cav-1 expression suggesting a role for rafts but not for caveolae in PrPC endocytosis. PrPC internalization is also affected by knock down of clathrin and by the expression of dominant negative Eps15 and Dynamin 2 mutants, indicating the involvement of a clathrin-dependent pathway. Notably, PrPC co-immunoprecipitates with clathrin and remains associated with detergent-insoluble microdomains during internalization thus indicating that PrPC can enter the cell via multiple pathways and that rafts and clathrin cooperate in its internalization.


These findings are of particular interest if we consider that the internalization route-s undertaken by PrPC can be crucial for the ability of different prion strains to infect and to replicate in different cell lines.

Autor: Daniela Sarnataro , Anna Caputo , Philippe Casanova, Claudia Puri, Simona Paladino, Simona S. Tivodar, Vincenza Campana, Carlo Ta



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