PTEN regulates RPA1 and protects DNA replication forks

Area of Science:

• Molecular Biology
• Genetics
• Cancer Research

Background:

• PTEN (Phosphatase and tensin homolog) is a critical tumor suppressor involved in cell signaling and genome stability.
• Replication stress can lead to DNA damage and chromosomal instability, contributing to tumorigenesis.

Purpose of the Study:

• To investigate the role of PTEN in protecting DNA replication forks during replication stress.
• To elucidate the molecular mechanisms by which PTEN safeguards replication forks.

Main Methods:

• Utilized PTEN knockout models and hydroxyurea treatment to induce replication stress.
• Employed STORM and iPOND imaging to visualize protein localization at replication sites.
• Investigated protein-protein interactions between PTEN, RPA1, and OTUB1.
• Assessed the impact of RPA1 deletion on replication fork stability and tumorigenesis in mice.

Main Results:

• PTEN deletion resulted in replication fork collapse and chromosomal instability under stress.
• PTEN physically interacts with RPA1 and promotes its accumulation at replication forks.
• PTEN recruits OTUB1 to deubiquitinate RPA1, a key step in fork protection.
• RPA1 deletion mimicked PTEN knockout phenotypes; RPA1 heterozygous disruption promoted tumorigenesis.

Conclusions:

• PTEN is essential for protecting DNA replication forks against stress-induced collapse.
• RPA1 is a direct target of PTEN's fork protection function.
• PTEN-mediated regulation of RPA1 is critical for maintaining genome stability and preventing cancer progression.