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Researchers investigated how eukaryotic cells control their growth rate by examining the relationship between ribosomes, mRNA, and protein synthesis in budding yeast across 15 different nutrient conditions. They found that cells accelerate growth primarily by proportionally increasing both ribosome and mRNA concentrations together, while the speed of protein synthesis itself remains constant at approximately 9 amino acids per second. A kinetic model based on mRNA-ribosome binding successfully predicts growth rates and cellular responses to perturbations, and experimentally blocking mRNA degradation confirmed that elevated mRNA levels can boost growth.
Why it matters
This work establishes a quantitative framework for understanding how cells regulate their proliferation, which has implications for cancer research, biotechnology applications like optimizing yeast for industrial fermentation, and understanding cellular responses to nutrient availability and stress conditions.
Understand the Science
arXiv:2508.14997v2 Announce Type: replace
Abstract: Cell growth underlies nearly all eukaryotic physiology, yet its quantitative principles remain unclear. Using single-molecule ribosome tracking, spike-in RNA sequencing, and quantitative proteomics across 15 nutrient-limited conditions in budding yeast, we define how growth is controlled in the budding yeast Saccharomyces cerevisiae. Ribosome concentration scales linearly with growth rate, while peptide elongation speed remains constant at ~9 amino acids/s. While elongation is not a regulatory lever, total mRNA concentration increases proportionally with ribosomes to accelerate growth. A simple kinetic model of mRNA-ribosome binding accurately predicts the fraction of active ribosomes, growth rate, and responses to transcriptional or size perturbations. Consistent with this model, transient inhibition of mRNA degradation boosts growth by elevating mRNA concentration. These results reveal that eukaryotic cells accelerate proliferation primarily by proportionally scaling mRNA and ribosome abundance, establishing a quantitative framework for understanding eukaryotic biosynthesis.
Source: The proportional scaling of mRNA and ribosome concentrations controls eukaryotic cell growth