Revealing Dynamic Protein Acetylation across Subcellular Compartments

Protein acetylation is a widespread
post-translational modification
implicated in many cellular processes. Recent advances in mass spectrometry
have enabled the cataloging of thousands of sites throughout the cell;
however, identifying regulatory acetylation marks have proven to be
a daunting task. Knowledge of the kinetics and stoichiometry of site-specific
acetylation is an important factor to uncover function. Here, an improved
method of quantifying acetylation stoichiometry was developed and
validated, providing a detailed landscape of dynamic acetylation stoichiometry
within cellular compartments. The dynamic nature of site-specific
acetylation in response to serum stimulation was revealed. In two
distinct human cell lines, growth factor stimulation led to site-specific,
temporal acetylation changes, revealing diverse kinetic profiles that
clustered into several groups. Overlap of dynamic acetylation sites
among two different human cell lines suggested similar regulatory
control points across major cellular pathways that include splicing,
translation, and protein homeostasis. Rapid increases in acetylation
on protein translational machinery suggest a positive regulatory role
under progrowth conditions. Finally, higher median stoichiometry was
observed in cellular compartments where active acetyltransferases
are well described. Data sets can be accessed through ProteomExchange
via the MassIVE repository (ProteomExchange: PXD014453; MassIVE: MSV000084029).