Large-Scale Identification of Protein Crotonylation Reveals Its Role in Multiple Cellular Functions

Lysine
crotonylation on histones is a recently identified post-translational
modification that has been demonstrated to associate with active promoters
and to directly stimulate transcription. Given that crotonyl-CoA is
essential for the acyl transfer reaction and it is a metabolic intermediate
widely localized within the cell, we postulate that lysine crotonylation
on nonhistone proteins could also widely exist. Using specific antibody
enrichment followed by high-resolution mass spectrometry analysis,
we identified hundreds of crotonylated proteins and lysine residues.
Bioinformatics analysis reveals that crotonylated proteins are particularly
enriched for nuclear proteins involved in RNA processing, nucleic
acid metabolism, chromosome organization, and gene expression. Furthermore,
we demonstrate that crotonylation regulates HDAC1 activity, expels
HP1α from heterochromatin, and inhibits cell cycle progression
through S-phase. Our data thus indicate that lysine crotonylation
could occur in a large number of proteins and could have important
regulatory roles in multiple nuclei-related cellular processes.