Yeast [PSI+] Prion Aggregates Are Formed by Small Sup35 Polymers Fragmented by Hsp104

The yeast [PSI+] determinant is related to formation of large prion-like aggregates of the conformationally altered Sup35 protein. Here, we show that these aggregates are composed of small Sup35 prion polymers and associated proteins. In contrast to other protein complexes of yeast lysates, but simi...

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Bibliographic Details
Published in:The Journal of biological chemistry 2003-12, Vol.278 (49), p.49636-49643
Main Authors: Kryndushkin, Dmitry S., Alexandrov, Ilya M., Ter-Avanesyan, Michael D., Kushnirov, Vitaly V.
Format: Article
Language:English
Subjects:
Biopolymers - metabolism
Heat-Shock Proteins - metabolism
Hsp104 protein
Peptide Termination Factors
Prions - biosynthesis
Prions - metabolism
Saccharomyces cerevisiae Proteins - biosynthesis
Saccharomyces cerevisiae Proteins - metabolism
Sodium Dodecyl Sulfate
Sup35 protein
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Summary:The yeast [PSI+] determinant is related to formation of large prion-like aggregates of the conformationally altered Sup35 protein. Here, we show that these aggregates are composed of small Sup35 prion polymers and associated proteins. In contrast to other protein complexes of yeast lysates, but similarly to amyloid fibers, these polymers are insoluble in SDS at room temperature. The polymers on average are about 30-fold smaller than the aggregates and comprise from 8 to 50 Sup35 monomers. The size of polymers is characteristic of a given [PSI+] variant and differs between the variants. Blocked expression of Hsp104 chaperone causes gradual increase in the size of prion polymers, while inactivation of Hsp104 by guanidine HCl completely stops their fragmentation, which shows indispensability of Hsp104 for this process.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M307996200