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bioRxiv · 10.1101/2021.01.26.428255

The regulatory landscape of the human HPF1- and ARH3-dependent ADP-ribosylome

Hendriks, I. A.·Buch-Larsen, S. C.·Prokhorova, E.·Rebak, A. K. L. F. S.·Ahel, I.·Nielsen, M. L.
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Abstract

Despite the involvement of Poly(ADP-ribose) polymerase-1 (PARP1) in many important biological pathways, the target residues of PARP1-mediated ADP-ribosylation remain ambiguous. To explicate the ADP-ribosylation regulome, we analyzed human cells depleted for key regulators of PARP1 activity, histone PARylation factor 1 (HPF1) and ADP-ribosylhydrolase 3 (ARH3). Using quantitative proteomics, we quantified 1,596 ADPr sites, displaying a thousand-fold regulation across investigated knockout cells. We find that HPF1 and ARH3 inversely and homogenously regulate the serine ADP-ribosylome on a proteome-wide scale with consistent adherence to lysine-serine (KS)-motifs suggesting targeting is independent of HPF1 and ARH3. Our data reveal that ADPr globally exists as mono-ADP-ribosylation, and we detail a remarkable degree of histone co-modification with ADPr and other post-translational modifications. Strikingly, no HPF1-dependent target residue switch from serine to glutamate/aspartate was detectable in cells, which challenges current dogma related to PARP1 target residues. Collectively, we elucidate hitherto unappreciated processes related to cellular PARP1 activity.

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Hendriks, I. A., Buch-Larsen, S. C., Prokhorova, E., Rebak, A. K. L. F. S., Ahel, I., Nielsen, M. L.. 2021-01-27. The regulatory landscape of the human HPF1- and ARH3-dependent ADP-ribosylome. https://doi.org/10.1101/2021.01.26.428255

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