Ferreira, P.C. and Ness, F. and Edwards, S.R. and Cox, B.S. and Tuite, M.F. (2001) The Elimination of the Yeast [PSI+] Prion by Guanidine Hydrochloride is the result of Hsp104 Inactivation. Molecular Microbiology, 40 (6). pp. 1357-1369. ISSN 0950-382X.
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In the yeast Saccharomyces cerevisiae, Sup35p (eRF3), a subunit of the translation termination complex, can take up a prion-like, self-propagating conformation giving rise to the non-Mendelian [PSI+] determinant. The replication of [PSI+] prion seeds can be readily blocked by growth in the presence of low concentrations of guanidine hydrochloride (GdnHCl), leading to the generation of prion-free [psi-] cells. Here, we provide evidence that GdnHCl blocks seed replication in vivo by inactivation of the molecular chaperone Hsp104. Although growth in the presence of GdnHCl causes a modest increase in HSP104 expression (20-90%), this is not sufficient to explain prion curing. Rather, we show that GdnHCl inhibits two different Hsp104-dependent cellular processes, namely the acquisition of thermotolerance and the refolding of thermally denatured luciferase. The inhibitory effects of GdnHCl protein refolding are partially suppressed by elevating the endogenous cellular levels of Hsp104 using a constitutive promoter. The kinetics of GdnHCl-induced [PSI+] curing could be mimicked by co-expression of an ATPase-negative dominant HSP104 mutant in an otherwise wild-type [PSI+] strain. We suggest that GdnHCl inactivates the ATPase activity of Hsp104, leading to a block in the replication of [PSI+] seeds.
|Additional information:||0950-382X (Print) Journal Article Research Support, Non-U.S. Gov't|
|Uncontrolled keywords:||Fungal Proteins/*drug effects/*metabolism Gene Expression Regulation, Fungal/drug effects Guanidine/*pharmacology Heat Heat-Shock Proteins/drug effects/genetics/*metabolism Kinetics Luciferases/chemistry/genetics/metabolism Prions/drug effects/metabolism Recombinant Proteins/chemistry/genetics/metabolism Saccharomyces cerevisiae/drug effects/*physiology *Saccharomyces cerevisiae Proteins|
|Subjects:||Q Science > QR Microbiology|
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences > Protein Science Group|
|Depositing User:||Mick Tuite|
|Date Deposited:||30 Sep 2008 18:46|
|Last Modified:||14 Jan 2010 14:20|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/5463 (The current URI for this page, for reference purposes)|
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