Phosphorylation of initiation factor eIF2 in response to stress conditions is mediated by acidic ribosomal P1/P2 proteins in Saccharomyces cerevisiae.

ABSTRACT: Eukaryotic cells contain an unusually large cytoplasmic pool of P1/P2 phosphoproteins, which form the highly flexible 60S subunit stalk that is required to interact with and activate soluble translation factors. In cells, cytoplasmic P1/P2 proteins are exchanged for ribosome-bound proteins in a process that can modulate ribosome function and translation. Here, we analysed different S. cerevisiae stalk mutants grown under stress conditions that result in eIF2α phosphorylation. These mutants either lack a cytoplasmic pool of stalk proteins or contain free but not ribosome-bound proteins. Only cells that contain free P1/P2 proteins induce eIF2 phosphorylation in vivo in response to glucose starvation or osmotic stress. Moreover, we show that free S. cerevisiae P1/P2 proteins can induce in vit

SUBMITTER: Jimenez-Diaz A 

PROVIDER: S-EPMC3877244 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature