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PARP1-TRIM44-MRN loop dictates the response to PARP inhibitors
Yonghyeon Kim1, Sunwoo Min1,2, Soyeon Kim3
1Department of Biochemistry, Ajou University School of Medicine, Suwon 16499, Republic of Korea.
Nucleic Acids Research
|September 1, 2024
Summary
Researchers identified TRIM44 as a key mediator in DNA repair. This protein links PARP1 to the ATM pathway, influencing homologous recombination repair (HRR) and potentially enhancing PARP inhibitor effectiveness.
Area of Science:
- Molecular Biology
- Genetics
- Cancer Research
Background:
- Poly (ADP-ribose) polymerase inhibitors (PARPi) demonstrate efficacy in tumors with homologous recombination repair (HRR) defects.
- The precise mechanism activating the HRR pathway in PARPi-treated cells remains unclear.
Purpose of the Study:
- To identify the mediator connecting PARP1 and ATM pathways in DNA repair.
- To elucidate the role of TRIM44 in homologous recombination repair and PARPi response.
Main Methods:
- Screening of 211 human ubiquitin-related proteins to identify key mediators.
- Investigating the interaction of TRIM44 with PARP1 and the MRN complex.
- Assessing the impact of TRIM44 knockdown on cellular sensitivity to olaparib.
Main Results:
- TRIM44 was identified as a crucial mediator that recruits the MRN complex to damaged chromatin, independent of PARP1 activity.
- TRIM44 regulates the ubiquitination-PARylation balance of PARP1, facilitating MRN complex recruitment for double-strand break (DSB) repair.
- TRIM44 knockdown increased sensitivity to olaparib and overcame resistance associated with 53BP1 deficiency.
Conclusions:
- TRIM44 plays a central role in linking PARP1 to the ATM-mediated DNA repair pathway.
- Targeting TRIM44 could enhance PARPi efficacy and potentially expand their application to HR-proficient tumors.
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