Genome dilution by cell growth drives starvation-like proteome remodeling in mammalian and yeast cells

SUMMARY Cell size is tightly controlled in healthy tissues and single-celled organisms, but it remains unclear how size influences cell physiology. Increasing cell size was recently shown to remodel the proteomes of cultured human cells, demonstrating that large and small cells of the same type can be biochemically different. Here, we corroborate these results in mouse hepatocytes and extend our analysis using yeast. We find that size-dependent proteome changes are highly conserved and mostly independent of metabolic state. As eukaryotic cells grow larger, the dilution of the genome elicits a starvation-like proteome phenotype, suggesting that growth in large cells is limited by the genome in a manner analogous to a limiting nutrient. We also find that this phenomenon explains many proteomic changes ascribed to yeast aging. Overall, our data suggest that genome concentration is a universal determinant of proteome content in growing cells.