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Updated: Jan 10, 2026

Visualization of DNA Repair Proteins Interaction by Immunofluorescence
Published on: June 26, 2020
Nuclear DAB2IP regulates DNA replication initiation through activating PLK1-mediated HBO1 phosphorylation
Zeng-Fu Shang1, Lan Yu2, Ciara Newman1
1Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas TX 75390, United States.
Disabled homolog 2 interacting protein (DAB2IP) promotes DNA replication initiation and maintains genome stability. Its interaction with HBO1 and phosphorylation by CDK1 are crucial for DNA replication and cellular homeostasis.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Disabled homolog 2 interacting protein (DAB2IP) is a known tumor suppressor involved in cell cycle regulation.
- Previous studies linked DAB2IP to mitosis progression via PLK1.
- The precise role of DAB2IP in DNA replication remained unclear.
Purpose of the Study:
- To investigate the novel function of DAB2IP in DNA replication origin firing.
- To elucidate the molecular mechanisms underlying DAB2IP's role in DNA replication.
- To understand how DAB2IP contributes to maintaining genome integrity.
Main Methods:
- Nuclear localization and interaction studies of DAB2IP.
- Analysis of HBO1 and PLK1 interactions and phosphorylation.
- Assessment of histone H3 acetylation (H3K14Ac) and MCM complex loading.
- Investigation of ATR and CDK1 regulation of DAB2IP phosphorylation.
- Evaluation of genomic instability markers upon DAB2IP ablation or phosphorylation defects.
Main Results:
- DAB2IP interacts with HBO1 in the nucleus, enhancing HBO1-PLK1 interaction and PLK1-mediated HBO1 phosphorylation.
- HBO1-directed H3K14Ac facilitates minichromosome maintenance (MCM) complex loading onto chromatin.
- ATR-regulated CDK1-mediated phosphorylation of DAB2IP is essential for HBO1-PLK1 complex formation and activation.
- Loss of DAB2IP phosphorylation leads to genomic instability, incomplete DNA replication, and accumulation of ultrafine bridges and 53BP1 bodies.
Conclusions:
- DAB2IP plays a critical role in initiating DNA replication by regulating HBO1 activity.
- DAB2IP phosphorylation by CDK1 is vital for DNA replication and genomic stability.
- These findings reveal a novel mechanism for DAB2IP in maintaining cellular homeostasis through DNA replication control.
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