Interactome of intact chromatosome variants with site-specifically ubiquitylated and acetylated linker histone H1.2.

Post-translational modifications (PTMs) of histones have fundamental effects on chromatin structure and function. While the impact of PTMs on the function of core histones are increasingly well understood, this is much less the case for modifications of linker histone H1, which is at least in part due to a lack of proper tools. In this work, we establish the assembly of intact chromatosomes containing site-specifically ubiquitylated and acetylated linker histone H1.

Chemoproteomic discovery of a human RNA ligase.

RNA ligases are present across all forms of life. While enzymatic RNA ligation between 5'-PO and 3'-OH termini is prevalent in viruses, fungi, and plants, such RNA ligases are yet to be identified in vertebrates. Here, using a nucleotide-based chemical probe targeting human AMPylated proteome, we have enriched and identified the hitherto uncharacterised human protein chromosome 12 open reading frame 29 (C12orf29) as a human enzyme promoting RNA ligation between 5'-PO and 3'-OH termini.

The Alarmone Diadenosine Tetraphosphate as a Cosubstrate for Protein AMPylation.

Diadenosine polyphosphates (Ap As) are non-canonical nucleotides whose cellular concentrations increase during stress and are therefore termed alarmones, signaling homeostatic imbalance. Their cellular role is poorly understood. In this work, we assessed Ap As for their usage as cosubstrates for protein AMPylation, a post-translational modification in which adenosine monophosphate (AMP) is transferred to proteins.