MAD2L2 dimerization and TRIP13 control shieldin activity in DNA repair.

Area of Science:

• Molecular Biology
• DNA Repair Mechanisms
• Protein Complex Assembly

Background:

• MAD2L2 (REV7) is a key component of the shieldin complex, essential for DNA double-strand break repair.
• The shieldin complex, comprising MAD2L2, SHLD1, SHLD2, and SHLD3, regulates DNA repair pathway selection by inhibiting DNA end-resection.

Purpose of the Study:

• To investigate the molecular requirements for shieldin complex assembly and its functional activity.
• To elucidate the role of MAD2L2 dimerization and its interaction with other shieldin components and TRIP13.

Main Methods:

• Investigated shieldin complex assembly and activity using biochemical assays.
• Analyzed the impact of MAD2L2 dimerization-defective mutants on shieldin function.
• Examined the interaction between the shieldin complex and TRIP13 ATPase.

Main Results:

• MAD2L2 dimerization, facilitated by SHLD2, is critical for shieldin assembly and promotes interaction with SHLD3.
• Dimerization-defective MAD2L2 impairs shieldin assembly and non-homologous end joining (NHEJ) DNA repair.
• Shieldin complex interaction with TRIP13 ATPase is dependent on MAD2L2 dimerization and SHLD3, influencing shieldin dynamics and DNA repair activity.

Conclusions:

• MAD2L2 dimerization is essential for shieldin complex assembly, stability, and function in DNA repair.
• TRIP13 ATPase plays a regulatory role in shieldin complex (dis)assembly and activity.
• These findings provide critical insights into the intricate regulation of DNA double-strand break repair by the shieldin complex.