The interactome of site-specifically acetylated linker histone H1

Linker histone H1 plays a key role in chromatin organization and maintenance, however, our knowledge of the regulation of H1 functions by its posttranslational modifications (PTMs) is very limited. In this study, we report on the generation of homogeneously and site-specifically mono- and di-acetylated H1 (H1 Ac) using genetic code expansion. We used these modified histones to identify and comprehensively characterize the acetylation-dependent cellular interactome for linker histone H1 and show that site-specific acetylation results in overlapping, but distinct groups of interacting partners. Intriguingly, H1 acetylation-specific interactors comprise translational initiation factors and are involved in transcriptional regulation, suggesting that acetylation of H1 may indeed act as a regulator of the linker histone H1 by modulation of protein-protein interactions.