Skip to Content
Merck
  • Mitochondrial PARP1 regulates NAD+-dependent poly ADP-ribosylation of mitochondrial nucleoids.

Mitochondrial PARP1 regulates NAD+-dependent poly ADP-ribosylation of mitochondrial nucleoids.

Experimental & molecular medicine (2022-12-07)
Jong-Hyuk Lee, Mansoor Hussain, Edward W Kim, Shang-Jung Cheng, Anthony K L Leung, Nima Borhan Fakouri, Deborah L Croteau, Vilhelm A Bohr
ABSTRACT

PARPs play fundamental roles in multiple DNA damage recognition and repair pathways. Persistent nuclear PARP activation causes cellular NAD+ depletion and exacerbates cellular aging. However, very little is known about mitochondrial PARP (mtPARP) and poly ADP-ribosylation (PARylation). The existence of mtPARP is controversial, and the biological roles of mtPARP-induced mitochondrial PARylation are unclear. Here, we demonstrate the presence of PARP1 and PARylation in purified mitochondria. The addition of the PARP1 substrate NAD+ to isolated mitochondria induced PARylation, which was suppressed by treatment with the inhibitor olaparib. Mitochondrial PARylation was also evaluated by enzymatic labeling of terminal ADP-ribose (ELTA). To further confirm the presence of mtPARP1, we evaluated mitochondrial nucleoid PARylation by ADP ribose-chromatin affinity purification (ADPr-ChAP) and PARP1 chromatin immunoprecipitation (ChIP). We observed that NAD+ stimulated PARylation and TFAM occupancy on the mtDNA regulatory region D-loop, inducing mtDNA transcription. These findings suggest that PARP1 is integrally involved in mitochondrial PARylation and that NAD+-dependent mtPARP1 activity contributes to mtDNA transcriptional regulation.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-TFAM Antibody, serum, from rabbit
Sigma-Aldrich
Anti-pan-ADP-ribose binding reagent, from Escherichia coli