Hsp110 chaperones regulate prion formation and propagation in S. cerevisiae by two discrete activities.

ABSTRACT: The cytosolic chaperone network of Saccharomyces cerevisiae is intimately associated with the emergence and maintenance of prion traits. Recently, the Hsp110 protein, Sse1, has been identified as a nucleotide exchange factor (NEF) for both cytosolic Hsp70 chaperone family members, Ssa1 and Ssb1. We have investigated the role of Sse1 in the de novo formation and propagation of [PSI(+)], the prion form of the translation termination factor, Sup35. As observed by others, we find that Sse1 is essential for efficient prion propagation. Our results suggest that the NEF activity is required for maintaining sufficient levels of substrate-free Ssa1. However, Sse1 exhibits an additional NEF-independent activity; it stimulates in vitro nucleation of Sup35NM, the prion domain of Sup35. We also observe

SUBMITTER: Sadlish H 

PROVIDER: S-EPMC2258148 | biostudies-literature | 2008 Mar

REPOSITORIES: biostudies-literature