Project description:Proteotoxic stress triggers adaptive cellular responses, including changes in gene expression on the levels of transcription and translation. In this study, we analyzed the translational response of yeast cells to impaired protein import into mitochondria, a condition under which mitochondrial precursor proteins accumulate in the cytosol and impose proteotoxic stress. We analyzed changes in translational efficiency as well as more subtle changes in the distribution of ribosomes along transcripts, with a special focus on translation initiation sites.
Project description:Aneuploidy and aging are correlated; however, a causal link between these two phenomena has remained elusive. Here we show that yeast disomic for a single native yeast chromosome generally have a decreased replicative lifespan. In addition, the extent of this lifespan deficit correlates with the size of the extra chromosome. We identified a mutation in BUL1 that rescues both the lifespan deficit and a protein trafficking defect in yeast disomic for chromosome 5. Bul1 is an E4 ubiquitin ligase adaptor involved in a protein quality-control pathway that targets membrane proteins for endocytosis and destruction in the lysosomal vacuole thereby maintaining protein homeostasis. Concurrent suppression of the aging and trafficking phenotypes suggests that disrupted membrane protein homeostasis in aneuploid yeast may contribute to their accelerated aging. The data reported here demonstrate that aneuploidy can impair protein homeostasis, shorten lifespan, and may contribute to age-associated phenotypes.