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- Title
A mutation within the C-terminal domain of Sup35p that affects [ PSI<sup>+</sup>] prion propagation.
- Authors
Kabani, Mehdi; Cosnier, Bruno; Bousset, Luc; Rousset, Jean-Pierre; Melki, Ronald; Fabret, Céline
- Abstract
Summary The epigenetic factor [ PSI+] in the yeast Saccharomyces cerevisiae is due to the prion form of Sup35p. The N-terminal domain of Sup35p (N), alone or together with the middle-domain (NM), assembles in vitro into fibrils that induce [ PSI+] when introduced into yeast cells. The Sup35p C-terminal domain (C), involved in translation termination, is essential for growth. The involvement of Sup35p C-terminal domain into [ PSI+] propagation is subject to debate. We previously showed that mutation of threonine 341 within Sup35p C-domain affects translation termination efficiency. Here, we demonstrate that mutating threonine 341 to aspartate or alanine results in synthetic lethality with [ PSI+] and weakening of [ PSI+] respectively. The corresponding Sup35D and Sup35A proteins assemble into wild-type like fibrils in vitro, but with a slower elongation rate. Moreover, cross-seeding between Sup35p and Sup35A is inefficient both in vivo and in vitro, suggesting that the point mutation alters the structural properties of Sup35p within the fibrils. Thus, Sup35p C-terminal domain modulates [ PSI+] prion propagation, possibly through a functional interaction with the N and/or M domains of the protein. Our results clearly demonstrate that Sup35p C-terminal domain plays a critical role in prion propagation and provide new insights into the mechanism of prion conversion.
- Publication
Molecular Microbiology, 2011, Vol 81, Issue 3, p640
- ISSN
0950-382X
- Publication type
Academic Journal
- DOI
10.1111/j.1365-2958.2011.07719.x