Increased expression of Hsp40 chaperones, transcriptional factors, and ribosomal protein Rpp0 can cure yeast prions

J Biol Chem. 2002 Jun 28;277(26):23702-8. doi: 10.1074/jbc.M111547200. Epub 2002 Mar 28.


The Sup35 (eRF3) translation termination factor of Saccharomyces cerevisiae can undergo a prion-like conformational conversion, thus resulting in the [PSI(+)] nonsense-suppressor determinant. In vivo this process depends critically on the chaperone Hsp104, whose lack or overexpression can cure [PSI(+)]. The use of artificial prion [PSI(+)PS] based on a hybrid Sup35PS with prion domain from the yeast Pichia methanolica allowed us to uncover three more chaperones, Ssb1, Ssa1, and Ydj1, whose overexpression can cure prion determinants. Here, we used the [PSI(+)PS] to search a multicopy yeast genomic library for novel factors able to cure prions. It was found that overexpression of the Hsp40 family chaperones Sis1 and Ynl077w, chaperone Sti1, transcriptional factors Sfl1 and Ssn8, and acidic ribosomal protein Rpp0 can interfere with propagation and manifestation of [PSI(+)PS] in a prion strain-specific manner. Some of these factors also affected the manifestation and propagation of conventional [PSI(+)]. Excess of Sfl1, Ssn8, and Rpp0 influenced at least one of the tested chaperone-specific promoters, SSA4, HSP104, and model promoters, with either the heat shock or stress response elements. Thus, the induction of chaperone expression by these proteins could explain their prion-curing effects.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cyclin-Dependent Kinases*
  • Cyclins / genetics
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • HSP40 Heat-Shock Proteins
  • Heat-Shock Proteins / biosynthesis*
  • Hot Temperature
  • Molecular Chaperones / metabolism
  • Pichia / genetics*
  • Plant Proteins*
  • Prions / metabolism*
  • Ribosomal Proteins / biosynthesis*
  • Saccharomyces cerevisiae Proteins*
  • Transcription Factors / biosynthesis*


  • Cyclins
  • Fungal Proteins
  • HSP40 Heat-Shock Proteins
  • Heat-Shock Proteins
  • Molecular Chaperones
  • Plant Proteins
  • Prions
  • RPP0 protein, Zea mays
  • Ribosomal Proteins
  • SFL1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • SSN8 protein, S cerevisiae
  • Cyclin-Dependent Kinases