SUMO-2 Orchestrates Chromatin Modifiers in Response to DNA Damage

Area of Science:

• Molecular Biology
• Cellular Biology
• Biochemistry

Background:

• Small ubiquitin-like modifiers (SUMO) are crucial for cellular processes, including the DNA damage response (DDR).
• Understanding SUMOylation dynamics in mammalian DDR is essential for elucidating DNA repair mechanisms.

Purpose of the Study:

• To identify dynamically regulated SUMO-2 conjugates and modification sites in response to DNA damage.
• To explore the role of SUMOylation in mammalian DDR pathways.

Main Methods:

• Quantitative proteomics was used to analyze SUMO-2 conjugates and modification sites.
• Cells were treated with methyl methanesulfonate (MMS) to induce DNA damage.

Main Results:

• Identified 20 upregulated and 33 downregulated SUMO-2 conjugates, with 362 dynamic SUMO-2 sites out of 755 total.
• Discovered dynamically SUMOylated networks involving chromatin modifiers, transcription factors, and DNA repair factors.
• Showcased differential regulation of JARID1B (degraded) and JARID1C (recruited to chromatin) via SUMOylation.

Conclusions:

• SUMOylation plays a significant, dynamic role in the mammalian DDR, distinct from yeast.
• Specific chromatin modifiers are key targets of SUMOylation during DNA damage.
• SUMOylation regulates protein stability and localization critical for DNA repair.