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

作者：Oishi Keita; Kurahashi Hiroshi; Pack Chan Gi; Sako Yasushi; Nakamura Yoshikazu^*

来源：MicrobiologyOpen, 2013, 2(3): 415-430.

DOI：10.1002/mbo3.83

• Amyloid
• Lsm4
• Pin(+) factor
• Q/N-rich protein
• yeast prion

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.

• 出版日期2013-6
• 单位河北医科大学