Real-time visualization of prion transport in single live cells using quantum dots.

Prion diseases are fatal neurodegenerative disorders resulting from structural conversion of the cellular isoform of PrP(C) to the infectious scrapie isoform PrP(Sc). It is believed that such structural alteration may occur within the internalization pathway. However, there is no direct evidence to support this hypothesis. Employing quantum dots (QDs) as a probe, we have recorded a real-time movie demonstrating the process of prion internalization in a living cell for the first time. The entire internalization process can be divided into four discrete but connected stages. In addition, using methyl-beta-cyclodextrin to disrupt cell membrane cholesterol, we show that lipid rafts play an important role in locating cellular PrP(C) to the cell membrane and in initiating PrP(C) endocytosis. Copyright 2010 Elsevier Inc. All rights reserved.