Abstract

Sequence-specific nucleated protein aggregation underlies the pathogenesis of most neurodegenerative diseases and constitutes the molecular basis of prion formation. Nevertheless, prion disorders have been distinguished from classical neurodegenerative diseases by virtue of their ability to be transmitted between individuals. In this lecture I will argue that prion-like propagation of pathogenic aggregated forms can explain the well-documented stereotypical spread of disease pathology in neurodegenerative disorders such as Huntington’s, Lou Gehrig’s, Alzheimer’s and Parkinson’s diseases. I will present data demonstrating that fibrillar polyglutamine aggregates like those associated with Huntington’s disease can be internalized by mammalian cells in culture where they gain access to the cytosolic compartment and become co-sequestered in aggresomes together with components of the ubiquitin-proteasome system and cytoplasmic chaperones. I will also present recent unpublished data examining the biochemical and biophysical properties of protein aggregates and cell membranes that are necessary for cytoplasmic intrusion of aggregates and the implications for the pathogenesis and management of this class of conformational disease.