Proteomics program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
Ilsa T Kirby
Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, United States
Ivan Rodriguez Siordia
Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, United States
David Hutin
Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
Marit Rasmussen
Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
Denis M Grant
Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
Larry L David
Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, United States
Jason Matthews
Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada; Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
Michael L Nielsen
Proteomics program, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
Poly(ADP-ribose) polymerase 7 (PARP-7) has emerged as a critically important member of a large enzyme family that catalyzes ADP-ribosylation in mammalian cells. PARP-7 is a critical regulator of the innate immune response. What remains unclear is the mechanism by which PARP-7 regulates this process, namely because the protein targets of PARP-7 mono-ADP-ribosylation (MARylation) are largely unknown. Here, we combine chemical genetics, proximity labeling, and proteome-wide amino acid ADP-ribosylation site profiling for identifying the direct targets and sites of PARP-7-mediated MARylation in a cellular context. We found that the inactive PARP family member, PARP-13—a critical regulator of the antiviral innate immune response—is a major target of PARP-7. PARP-13 is preferentially MARylated on cysteine residues in its RNA binding zinc finger domain. Proteome-wide ADP-ribosylation analysis reveals cysteine as a major MARylation acceptor of PARP-7. This study provides insight into PARP-7 targeting and MARylation site preference.
