HPF1 and nucleosomes mediate a dramatic switch in activity of PARP1 from polymerase to hydrolase
Abstract
Poly(ADP-ribose) polymerase 1 (PARP1) is an important player in the response to DNA damage. Recently, histone PARylation factor (HPF1) was shown to be a critical modulator of the activity of PARP1 by facilitating PARylation of histones and redirecting the target amino acid specificity from acidic to serine residues. Here we investigate the mechanism and specific consequences of HPF1-mediated PARylation using nucleosomes as both activators and substrates for PARP1. HPF1 provides that catalytic base Glu284 to substantially redirect PARylation by PARP1 such that the histones in nucleosomes become the primary recipients of PAR chains. Surprisingly, HPF1 partitions most of the reaction product to free ADPR, resulting in much shorter PAR chains compared to reactions in the absence of HPF1. This HPF1-mediated switch from polymerase to hydrolase has important implications for the PARP1-mediated response to DNA damage and raises interesting new questions about the role of intracellular ADPR and depletion of NAD+.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for all Figures.
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Funding
National Cancer Institute (CA218255)
- Karolin Luger
Howard Hughes Medical Institute
- Karolin Luger
National Institutes of Health (T32GM008759)
- Genevieve Roberts
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Rudolph et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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