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Updated: Aug 13, 2026
Purification of Hsp104, a Protein Disaggregase
Published on: September 30, 2011
Guanidine hydrochloride inhibits Hsp104 activity in vivo: a possible explanation for its effect in curing yeast
1Building 8, Room 407, Laboratory of Biochemistry and Genetics, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0851, USA.
Abstract:
The presence of millimolar concentrations of guanidine hydrochloride (Gdn-HCl) in growth media causes efficient loss of the normally stable [PSI+] element from yeast cells. Although it has become common practice to include 5 mm Gdn-HCl in growth media to cure [PSI+] and other prions of yeast, the biochemical mechanism by which it cures is unknown. We find that 5 mm Gdn-HCl significantly reduces Hsp104-mediated basal and acquired thermotolerance. Gdn-HCl also reduced the ability of Hsp104 to restore activity of thermally denatured luciferase in vivo. The abundance of Hsp104 was not reduced in cells grown in the presence of Gdn-HCl, ruling out negative effects on expression or stability of Hsp104. We therefore conclude that Gdn-HCl inhibits Hsp104 activity in vivo. Since replication of yeast prions is dependent on Hsp104, our results suggest that Gdn-HCl cures prions by inhibiting Hsp104 activity.
Insights
Guanidine hydrochloride (Gdn-HCl) cures yeast prions by inhibiting the Hsp104 protein. This study reveals Gdn-HCl reduces Hsp104
Area of Science:
- Biochemistry
- Molecular Biology
- Yeast Genetics
Background:
- Yeast prions, like the [PSI+] element, are self-propagating protein aggregates.
- Guanidine hydrochloride (Gdn-HCl) is commonly used to eliminate yeast prions, but the mechanism is unclear.
- Hsp104 is a crucial chaperone protein involved in yeast prion replication and stability.
Purpose of the Study:
- To elucidate the biochemical mechanism by which Gdn-HCl cures yeast prions.
- To investigate the effect of Gdn-HCl on the function of the Hsp104 protein in vivo.
Main Methods:
- Yeast cell culture with varying concentrations of Gdn-HCl.
- Assessment of Hsp104-mediated thermotolerance (basal and acquired).
- In vivo refolding assay using thermally denatured luciferase.
- Quantification of Hsp104 protein levels via Western blotting.
Main Results:
- Gdn-HCl treatment significantly reduced Hsp104-mediated thermotolerance.
- Gdn-HCl impaired Hsp104's ability to restore denatured luciferase activity.
- Hsp104 protein abundance remained unaffected by Gdn-HCl exposure.
- Gdn-HCl was found to inhibit Hsp104 activity in vivo.
Conclusions:
- Guanidine hydrochloride inhibits the essential chaperone activity of Hsp104 within yeast cells.
- The prion-curing effect of Gdn-HCl is attributed to its inhibition of Hsp104.
- This finding provides a biochemical basis for the use of Gdn-HCl in prion elimination studies.
