Biological systems and soft materials:

Future directions in statistical physics

A symposium on the interface of statistical physics, biology, and chemistry

Department of Physics, Virginia Tech

Blacksburg, Virginia, USA

March 6 and 7, 2004

Invited talk:

Susan W. Liebman

Department of Biological Sciences, University of Illinois at Chicago

Prion-prion interactions in yeast

The infectious agent for certain neurodegenerative diseases, such as ‘mad cow’ disease, appears to be the PrP protein without any nucleic acid. Infectivity depends upon the shape into which the PrP protein is folded: when some PrP is in its disease-causing (‘prion’) conformation, it converts normal PrP into that form too. Several genetic traits in yeast, [PSI⁺], [PIN⁺] and [URE3], are propagated by this unusual ‘protein only’ mechanism, and although they involve proteins distinct from PrP, the term prion has been expanded to include them. I will discuss our work using yeast to elucidate factors that influence the de novo appearance and inheritance of prions. Surprisingly we find a cross-talk between different prions to be important in these processes.