Classification of protein half-lives in S. cerevisiae & S. pombe

Range Table - link
Organism Yeast
Reference Christiano R, Nagaraj N, Fröhlich F, Walther TC. Global proteome turnover analyses of the Yeasts S. cerevisiae and S. pombe. Cell Rep. 2014 Dec 11 9(5):1959-65. doi: 10.1016/j.celrep.2014.10.065. Supplemental Information p.S12 table S4PubMed ID25466257
Method p.1959 right column bottom paragraph:"To determine protein turnover rates systematically, [investigators] metabolically labeled the yeasts with heavy isotopes containing lysine (“heavy” lysine, H) and diluted the cells in an excess of normal lysine (“light” lysine, L) at the beginning of the experiment (Figures 1A, S1A, and S1B). [They] analyzed the decay of the heavy lysine signal in the proteome over time by high-resolution mass spectrometry-based proteomics (Schwanhäusser et al., 2011) (Figure 1B)."
Comments P.1960 right column bottom paragraph:"[Investigators’] analyses on the overwhelming majority of yeast proteins revealed three classes, representing three distinct regimes of protein abundance control (Figure 2A Table S4). Two classes appear to mediate the rapid and competitive growth of the two yeasts. Class I contains a small fraction (∼2% in S. cerevisiae and ∼1% in S. pombe) of very-short-lived proteins, many driving the cell cycle (p = 4.4 × 10^−3 Figure 2B), for which the degradation rates are at least twice the dilution rate due to cell growth (t1/2 < 1.25 hr in S. cerevisiae and t1/2 < 2 hr in S. pombe)." p.1963 right column bottom paragraph:"Complementary to ribosome profiling, which measures protein synthesis rates but does not predict the abundance of proteins that are degraded fast, [investigators’] data set reveals two classes of short-lived proteins. These classes are enriched in cellular regulators and likely constitute a good set of candidates for studying the different cellular protein degradation pathways. A comparison with available turnover data in mouse fibroblasts (Schwanhäusser et al., 2011) shows that the number of proteins in these classes, with significant protein degradation (classes I and II), expands with organismal complexity (Figure S2C Table S4). Likely, this is explained by the presence of many more posttranslationally regulated processes in mammalian cells."
Entered by Uri M
ID 112048