A bipolar functionality of Q/N-rich proteins: Lsm4 amyloid causes clearance of yeast prions

Keita Oishi, Hiroshi Kurahashi, Chan Gi Pack, Yasushi Sako, Yoshikazu Nakamura

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Prions are epigenetic modifiers that cause partially loss-of-function phenotypes of the proteins in Saccharomyces cerevisiae. The molecular chaperone network that supports prion propagation in the cell has seen a great progress in the last decade. However, the cellular machinery to activate or deactivate the prion states remains an enigma, largely due to insufficient knowledge of prion-regulating factors. Here, we report that overexpression of a [PSI+]-inducible Q/N-rich protein, Lsm4, eliminates the three major prions [PSI+], [URE3], and [RNQ+]. Subcloning analysis revealed that the Q/N-rich region of Lsm4 is responsible for the prion loss. Lsm4 formed an amyloid in vivo, which seemed to play a crucial role in the prion elimination. Fluorescence correlation spectroscopy analysis revealed that in the course of the Lsm4-driven [PSI+] elimination, the [PSI+] aggregates undergo a size increase, which ultimately results in the formation of conspicuous foci in otherwise [psi-]-like mother cells. We also found that the antiprion activity is a general property of [PSI+]-inducible factors. These data provoked a novel "unified" model that explains both prion induction and elimination by a single scheme.

Original languageEnglish
Pages (from-to)415-430
Number of pages16
JournalMicrobiologyOpen
Volume2
Issue number3
DOIs
Publication statusPublished - 2013 Jun

Keywords

  • Amyloid
  • Lsm4
  • Pin factor
  • Q/N-rich protein
  • Yeast prion.

ASJC Scopus subject areas

  • Microbiology

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