Chemical genetics and proteome-wide site mapping reveal cysteine MARylation by PARP-7 on immune-relevant protein targets

ABSTRACT: Poly(ADP-ribose) polymerase 7 (PARP7) has emerged as a critically important member of a large enzyme family that catalyze mono-ADP-ribosylation (MARylation) in mammalian cells. Unlike other PARPs, PARP7 is expressed in many different cell types and is upregulated by diverse stimuli, such as toxins, growth factors, steroid hormones, and immunomodulatory ligands. Recent evidence by several independent studies show that PARP7 is a critical regulator of the innate immune response. What remains unclear is the mechanism by which PARP7 regulates this process as well as other cellular processes. This is because the protein targets, and the specific amino acid sites, of PARP7 MARylation are largely unknown. Here, we combine chemical genetics, proximity labeling, and proteome-wide amino acid ADP-ribosylation (ADPr) site profiling for identifying the direct targets and sites of PARP7-mediated MARylation. We found that the inactive PARP family member, PARP13—a critical regulator of the innate antiviral immune response—is a major target of PARP7, and is preferentially MARylated on cysteine residues in its RNA binding zinc finger domain. Proteome-wide MARylation analysis reveals cysteine as a major ADPr acceptor of PARP7. These studies not only provide insight into PARP7 targeting and MARylation site preference, but also serve as an important resource for further understanding PARP7 function in the innate immune response and other pathways.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Permanent Cell Line Cell, Cell Culture

SUBMITTER: Sara Larsen  

LAB HEAD: Michael Lund Nielsen

PROVIDER: PXD020340 | Pride | 2021-11-04

REPOSITORIES: Pride