RAD18 methylation by the methyltransferase SETD6 attenuates DNA breaks

Area of Science:

• Molecular Biology
• Epigenetics
• DNA Repair Mechanisms

Background:

• SETD6 is a SET-domain-containing methyltransferase involved in post-translational modifications.
• RAD18 is a crucial protein in the DNA damage repair pathway.
• Protein methylation regulates protein function, stability, and interactions.

Purpose of the Study:

• To investigate the interaction between SETD6 and RAD18.
• To determine if SETD6 methylates RAD18 and elucidate the functional consequences of this modification.
• To understand the role of SETD6-mediated RAD18 methylation in maintaining genomic integrity.

Main Methods:

• Protein microarray technology to identify interactors.
• ELISA and immunoprecipitation assays to confirm interaction and methylation.
• Mass spectrometry and site-directed mutagenesis to identify methylation sites.
• Analysis of DNA damage markers (γH2AX) and comet assays in SETD6 knockout cells.

Main Results:

• RAD18 was identified as a direct interactor and substrate of SETD6.
• RAD18 undergoes mono-methylation at K73 and K406 residues by SETD6.
• SETD6-mediated methylation influences RAD18's nuclear localization.
• SETD6 depletion leads to increased DNA damage markers and DNA breaks.

Conclusions:

• SETD6-mediated methylation of RAD18 is essential for attenuating DNA breaks.
• This methylation regulates RAD18's cellular localization and function.
• SETD6 plays a critical role in maintaining genomic integrity through RAD18 regulation.