Some proteins in the cell live longer than others. While it is established that the turnover rates of different proteins within a cell are highly variable, it is not known how conserved the turnover rates of the same proteins across species are.

Researchers at University of Rochester led by Sina Ghaemmaghami attempted to answer this question by systematically measuring the proteome turnover kinetics in skin cells from eight different rodent species, including mouse, chiniclla and naked mole rat. The researchers used stable isotope labeling and mass spectrometry to quantify the rate of incorporation of heavy amino acid isotopes in order to calculate protein degradation rates and half-lives.

The team observed two striking trends. First, more closely related species have higher correlations of proteome turnover kinetics. Second, the higher the maximum lifespan of the species, the lower the global protein turnover rates.

To explain the latter unexpected trend, the investigators hypothesized that long-lived species may have evolved to reduce the energetic demands of continuous protein turnover, which would lessen the generation of reactive oxygen species and the subsequent oxidative damage.

This study was published in Molecular & Cellular Proteomics.