Multiomics of GCN4-dependent replicative lifespan extension models reveals Gcn4 as a regulator of protein turnover in yeast
We have shown that multiple tRNA synthetase inhibitors can increase lifespan in both the nematode C. elegans and the budding yeast S. cerevisiae by acting through the conserved transcription factor Gcn4 (yeast) / ATF-4 (worms). To further understand the biology downstream of this conserved transcription factor in the yeast model system, we looked at two different yeast models known to have both upregulated Gcn4, and GCN4-dependent increased replicative lifespan. These two models are rpl31a? yeast, and yeast treated with the tRNA synthetase inhibitor borrelidin. We used both proteomic and RNAseq analysis of a block experimental design that included both of these models, to identify GCN4-dependent changes in these two longlived strains of yeast. Proteomic analysis of these yeast indicate that the longlived yeast have increased abundance of proteins involved in amino acid biosynthesis. RNASeq of these same yeast uncovered further regulation of protein turnover, identifying the differential expression of genes associated with both autophagy and with the ubiquitin proteasome system. The data presented here further underscore the important role that GCN4 and its orthologs play in the maintenance of protein homeostasis, which is itself an important hallmark of aging. Importantly, these changes could also have wider-ranging implications in the understanding and treatment of diseases of aging characterized by protein aggregation. Overall design: a block-design, considering drug treatment, RPL31A genotype, and GCN4 genotype