SUMO Teams Up with a Translocase to Save TOPO

Area of Science:

• Molecular biology
• Genetics
• Biochemistry

Background:

• Topoisomerase II (Top2) is essential for DNA decatenation and plays a role in DNA repair.
• SUMOylation and ubiquitination are post-translational modifications that regulate protein function and stability.
• Dysregulation of Top2 activity can lead to genomic instability and disease.

Purpose of the Study:

• To investigate the role of SUMOylation in regulating Top2 stability and function.
• To elucidate the interplay between SUMO and ubiquitin pathways in genome maintenance.
• To understand how DNA translocases interact with Top2 and its modifying enzymes.

Main Methods:

• Biochemical assays to study Top2 activity and modification.
• Yeast and mammalian cell culture systems.
• Immunoblotting and immunoprecipitation techniques to detect SUMOylated and ubiquitinated Top2.
• DNA combing and comet assays to assess DNA breaks.

Main Results:

• Wei et al. (2017) demonstrate that a specific DNA translocase interacts with Top2.
• This interaction facilitates the SUMOylation of Top2, protecting it from ubiquitin-mediated degradation.
• SUMOylation of Top2 by the translocase activity minimizes the formation of DNA breaks during replication and transcription.

Conclusions:

• SUMOylation acts as a critical signal to stabilize Top2 and prevent its degradation.
• The interplay between SUMO and ubiquitin pathways is vital for maintaining genome integrity.
• Targeting this SUMO-dependent mechanism could offer new therapeutic strategies for genome instability disorders.