UBE2D3 facilitates NHEJ by orchestrating ATM signalling through multi-level control of RNF168

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Genome integrity is crucial, relying on controlled DNA damage response (DDR) and repair pathways.
• Phosphorylation and ubiquitination are key post-translational modifications in DDR, but their coordination is not fully understood.

Purpose of the Study:

• To identify regulators of ATM kinase-induced DDR that promote telomeric non-homologous end-joining (NHEJ).
• To elucidate the role of UBE2D3 in coordinating DDR signaling and NHEJ.

Main Methods:

• Investigated the function of ubiquitin-conjugating enzyme UBE2D3 in DNA damage response.
• Utilized techniques to assess chromatin ubiquitination, protein recruitment (53BP1), and kinase activity (ATM, KAP1 phosphorylation).
• Analyzed the impact of UBE2D3 deficiency on telomeric NHEJ and regulatory pathways.

Main Results:

• UBE2D3 regulates ATM-induced DDR and promotes telomeric NHEJ.
• UBE2D3 facilitates chromatin ubiquitination and 53BP1 recruitment via RNF168.
• UBE2D3 limits RNF168 accumulation and promotes KAP1-S824 phosphorylation, counteracting aberrant phosphatase activity.

Conclusions:

• UBE2D3 is a multi-level regulator of NHEJ, orchestrating ATM and RNF168 activities.
• A negative regulatory circuit in DDR, involving RNF168 and phosphatases restricting KAP1 phosphorylation, is constrained by UBE2D3.
• UBE2D3 plays a critical role in maintaining genome integrity through precise control of DNA repair pathways.