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bioRxiv · 10.1101/2023.06.24.546374

PARP14 is a writer, reader and eraser of mono-ADP-ribosylation

Torretta, A.·Chatzicharalampous, C.·Ebenwaldner, C.·Schuler, H.
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Abstract

PARP14/BAL2 is a large multidomain enzyme involved in signaling pathways with relevance to cancer, inflammation, and infection. Inhibition of its mono-ADP-ribosylating PARP homology domain and its three ADP-ribosyl binding macro domains has been regarded as a potential means of therapeutic intervention. Macrodomains-2 and -3 are known to stably bind to ADP-ribosylated target proteins; but the function of macrodomain-1 has remained some-what elusive. Here, we used biochemical assays of ADP-ribosylation levels to characterize PARP14 macrodomain-1 and the homologous macrodomain-1 of PARP9. Our results show that both macrodomains display an ADP-ribosyl glycohydrolase activity that is not directed toward specific protein side chains. PARP14 macrodomain-1 is unable to degrade poly(ADP-ribose), the enzymatic product of PARP1. The F926A mutation of PARP14 and the F244A mutation of PARP9 strongly reduced ADP-ribosyl glycohydrolase activity of the respective macrodomains, suggesting mech-anistic homology to the Mac1 domain of the SARS-CoV-2 Nsp3 protein. This study adds two new enzymes to the previously known six human ADP-ribosyl glycohydrolases. Our results have key implications for how PARP14 and PARP9 will be studied and how their functions will be understood.

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Torretta, A., Chatzicharalampous, C., Ebenwaldner, C., Schuler, H.. 2023-06-24. PARP14 is a writer, reader and eraser of mono-ADP-ribosylation. https://doi.org/10.1101/2023.06.24.546374

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