2. Academic Validation
  3. PARP1-driven repair of topoisomerase IIIα DNA-protein crosslinks by FEN1

PARP1-driven repair of topoisomerase IIIα DNA-protein crosslinks by FEN1

  • Cell Rep. 2024 Jul 18;43(8):114522. doi: 10.1016/j.celrep.2024.114522.
Liton Kumar Saha 1,  Yilun Sun 2,  Sourav Saha 2,  Xi Yang 2,  Yves Pommier 3
Affiliations

Affiliations

  • 1 Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA. Electronic address: liton.saha@nih.gov.
  • 2 Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
  • 3 Developmental Therapeutics Branch & Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA. Electronic address: pommier@nih.gov.
PMID: 39028621 DOI: 10.1016/j.celrep.2024.114522
Abstract

Persistent DNA-protein crosslinks formed by human Topoisomerase IIIα (TOP3A-DPCs) interfere with DNA metabolism and lead to genome damage and cell death. Recently, we demonstrated that such abortive TOP3A-DPCs are ubiquitylated and proteolyzed by Spartan (SPRTN). Here, we identify transient poly(ADP-ribosylation) (PARylation) in addition to ubiquitylation as a signaling mechanism for TOP3A-DPC repair and provide evidence that poly(ADP-ribose) polymerase 1 (PARP1) drives the repair of TOP3A-DPCs by recruiting flap Endonuclease 1 (FEN1) to the TOP3A-DPCs. We find that blocking PARylation attenuates the interaction of FEN1 and TOP3A and that TOP3A-DPCs accumulate in cells with compromised PARP1 activity and in FEN1-deficient cells. We also show that PARP1 suppresses TOP3A-DPC ubiquitylation and that inhibiting the ubiquitin-activating Enzyme E1 (UBE1) increases TOP3A-DPCs, consistent with ubiquitylation serving as a signaling mechanism for TOP3A-DPC repair mediated by SPRTN and TDP2. We propose that two concerted pathways repair TOP3A-DPCs: PARylation-driven FEN1 excision and ubiquitylation-driven SPRTN-TDP2 excision.

Keywords

CP: Molecular biology; FEN1; PARP1; PARylation; TOP3A-DPCs; ubiquitylation.

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