Precise Post-translational Tuning Occurs for Most Protein Complex Components during Meiosis

Summary: Protein degradation is known to be a key component of expression regulation for individual genes, but its global impact on gene expression has been difficult to determine. We analyzed a parallel gene expression dataset of yeast meiotic differentiation, identifying instances of coordinated protein-level decreases to identify new cases of regulated meiotic protein degradation, including of ribosomes and targets of the meiosis-specific anaphase-promoting complex adaptor Ama1. Comparison of protein and translation measurements over time also revealed that, although meiotic cells are capable of synthesizing protein complex members at precisely matched levels, they typically do not. Instead, the members of most protein complexes are synthesized imprecisely, but their protein levels are matched, indicating that wild-type eukaryotic cells routinely use post-translational adjustment of protein complex partner levels to achieve proper stoichiometry. Outlier cases, in which specific complex components show divergent protein-level trends, suggest timed regulation of these complexes. : Eisenberg et al. leverage global translation and protein data to identify cases of regulated protein degradation in meiosis. Analyses of temporal trends reveal that members of protein complexes can be synthesized at ideal stoichiometry but that they are usually made imprecisely and their levels adjusted by degradation. Keywords: protein complexes, meiosis, gene expression, ribosome, protein degradation, Ama1, translation, ribosome profiling, mass spectrometry, stoichiometr