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Updated: Aug 22, 2025
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Strand-Specific Analysis of Proteins at Replicating DNA Strands by Enrichment and Sequencing of Protein-Associated Nascent DNA Method
Published on: May 2, 2025
466
PARP1 proximity proteomics reveals interaction partners at stressed replication forks
Thorsten Mosler1, H Irem Baymaz1, Justus F Gräf1
1Institute of Molecular Biology (IMB), Mainz 55128, Germany.
Nucleic Acids Research
|November 9, 2022
Summary
TPX2 directly binds PARP1 (poly-ADP-ribose polymerase 1), regulating its activity during DNA replication stress. This interaction is crucial for cancer cells, particularly those with BRCA1/2 mutations, enhancing sensitivity to PARP inhibitors.
Area of Science:
- Molecular Biology
- Cancer Research
- Genetics
Background:
- PARP1 (poly-ADP-ribose polymerase 1) is crucial for DNA repair and targeted in BRCA1/2-deficient cancers.
- The role of PARP1 regulation at stressed replication forks is not well understood.
- BRCA1/2-deficient cells are vulnerable to PARP inhibitors due to loss of replication fork protection.
Purpose of the Study:
- To identify regulators of PARP1 activity at stressed replication forks.
- To investigate the role of TPX2 in DNA damage response and PARP1 regulation.
Main Methods:
- Proximity proteomics of PARP1.
- Isolation of proteins at stressed replication forks.
- Analysis of TPX2 expression in cancer patient data.
Main Results:
- TPX2 was identified as a direct PARP1-binding protein.
- TPX2 regulates PARP1 auto-ADP-ribosylation activity.
- TPX2 promotes homology-directed DNA repair and interacts with DNA damage response proteins.
- Increased TPX2 mRNA levels correlate with BRCA1/2 mutations and PARP inhibitor sensitivity in cancers.
Conclusions:
- TPX2 plays a mitosis-independent role in response to replication stress by interacting with PARP1.
- TPX2 is a potential therapeutic target for enhancing PARP inhibitor efficacy in BRCA1/2-deficient cancers.
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