[Rnq1 protein protects [PSI^(+)] prion from effect of the PNM mutation]

The interaction of [PSI^(+)] and [PIN^(+)] factors in yeast Saccharomyces cerevisiae is known as the first evidence of prions networks. In [PIN^(+)] cells, Rnq1p prion aggregates work as a template for Sup35p aggregation, which is essential for [PSI^(+)] induction. No additional factors are required for subsequent Sup35p aggregation. Nevertheless, several recent reports provide data that indicate a more complex interplay between these prions. Our results show that the presence of Rnq1p in the cell significantly decreases the loss of [PSI^(+)] prion, which is caused by a double mutation in SUP35 (Q61K, Q62K substitutions in the Sup35 protein). These observations support the existence of interaction networks that converge on a strong linkage of prionogenic and prion-like proteins, and the participation of Rnq1 protein in the maintenance of prion [PSI^(+)].