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A bipolar personality of yeast prion proteins

Hiroshi Kurahashi1, Keita Oishi, Yoshikazu Nakamura

  • 1Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, Tokyo, Japan.

Prion
|December 14, 2011
PubMed

Insights

Yeast prions like [PSI+] can be induced by overproducing Sup35. However, other prions ([RNQ+], [URE3]) and proteins can surprisingly inhibit [PSI+] prion formation and maintenance.

Area of Science:

  • Molecular Biology
  • Protein Biochemistry
  • Yeast Genetics

Background:

  • Prions are infectious proteins causing neurodegenerative diseases.
  • Saccharomyces cerevisiae harbors well-characterized prions: [PSI+], [RNQ+], and [URE3].
  • [PSI+] involves the translation termination factor Sup35; [RNQ+] involves Rnq1; [URE3] involves Ure2.

Purpose of the Study:

  • To investigate the complex interactions governing yeast prion formation and stability.
  • To elucidate the 'bipolar activity' of certain yeast prion proteins on the [PSI+] prion.

Main Methods:

  • Yeast genetics and prion induction experiments.
  • Overexpression of specific yeast prion proteins (Sup35, Rnq1, Ure2) and mutants (Rnq1Δ100).
  • Monitoring of [PSI+] prion de novo appearance and maintenance in different yeast strains.

Main Results:

  • Sup35 overproduction induces de novo [PSI+] in [RNQ+] or [URE3] strains.
  • [RNQ+] and [URE3] prions, Rnq1Δ100, and Lsm4 inhibit [PSI+] maintenance.
  • These factors exhibit a 'bipolar activity' influencing [PSI+] prion fate.

Conclusions:

  • Yeast prions display complex regulatory mechanisms beyond simple propagation.
  • The interactions between different prion proteins are crucial for prion dynamics.
  • Further research is needed to understand the molecular basis of this bipolar activity.

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