Mechanism of inhibition of Psi+ prion determinant propagation by a mutation of the N-terminus of the yeast Sup35 protein. |
| |
| Authors: | N V Kochneva-Pervukhova S V Paushkin V V Kushnirov B S Cox M F Tuite M D Ter-Avanesyan |
| |
| Affiliation: | Institute of Experimental Cardiology, Cardiology Research Center, 3rd Cherepkovskaya Street 15A, Moscow 121552, Russia. |
| |
| Abstract: | The SUP35 gene of Saccharomyces cerevisiae encodes the polypeptide chain release factor eRF3. This protein (also called Sup35p) is thought to be able to undergo a heritable conformational switch, similarly to mammalian prions, giving rise to the cytoplasmically inherited Psi+ determinant. A dominant mutation (PNM2 allele) in the SUP35 gene causing a Gly58-->Asp change in the Sup35p N-terminal domain eliminates Psi+. Here we observed that the mutant Sup35p can be converted to the prion-like form in vitro, but such conversion proceeds slower than that of wild-type Sup35p. The overexpression of mutant Sup35p induced the de novo appearance of Psi+ cells containing the prion-like form of mutant Sup35p, which was able to transmit its properties to wild-type Sup35p both in vitro and in vivo. Our data indicate that this Psi+-eliminating mutation does not alter the initial binding of Sup35p molecules to the Sup35p Psi+-specific aggregates, but rather inhibits its subsequent prion-like rearrangement and/or binding of the next Sup35p molecule to the growing prion-like Sup35p aggregate. |
| |
| Keywords: | |
|
|
