Quantifying dynamic protein acetylation using quantitative stoichiometry

Protein acetylation is a widespread post-translational modification that is implicated in many cellular processes. Emergent technologies such as mass spectrometry has catalogued thousands of sites throughout the cell, however identifying regulatory acetylation marks has proven to be a daunting task. Here, we reveal the dynamic nature of site-specific acetylation in response to serum stimulation. An improved method of quantifying acetylation stoichiometry was developed and validated, providing a detailed landscape of dynamic acetylation stoichiometry within cellular compartments. The nuclear compartment displayed significantly higher median stoichiometry, in line with the existence of known acetyltransferases. Site-specific, temporal acetylation using a serum starved-refed cell culture model uncovered distinct clusters of acetylations with diverse kinetic profiles. Of particular note, dynamic acetylation sites on protein translational machinery suggests a major regulatory role.