O-GlcNAc modification affects the ATM-mediated DNA damage response

Area of Science:

• Cellular biology
• Molecular biology
• Biochemistry

Background:

• O-Linked β-N-acetylglucosamine (O-GlcNAc) is a dynamic post-translational modification regulating nuclear, mitochondrial, and cytoplasmic proteins.
• The influence of O-GlcNAcylation on the ataxia-telangiectasia mutated (ATM)-mediated DNA damage response remains largely unexplored.
• It was unclear if ATM, a key protein in DNA double-strand break signaling, is itself a target of O-GlcNAcylation.

Purpose of the Study:

• To investigate the role of O-GlcNAcylation in the ATM-mediated DNA damage response.
• To determine if ATM is an O-GlcNAc-modified protein.
• To examine the functional impact of O-GlcNAcylation on ATM activation and recovery.

Main Methods:

• Utilized PUGNAc and DON inhibitors to modulate protein O-GlcNAcylation levels.
• Employed immunoprecipitation and immunoblot analyses to assess ATM O-GlcNAcylation and interaction with O-GlcNAc transferase (OGT).
• Studied ATM activation and recovery by monitoring de-phosphorylation of phospho-ATM in HeLa cells and primary neurons.

Main Results:

• Increased O-GlcNAcylation enhanced X-irradiation-induced ATM activation.
• Decreased O-GlcNAcylation did not alter ATM activation levels but delayed ATM activation and recovery.
• Confirmed that ATM is O-GlcNAc modified and interacts with OGT.

Conclusions:

• ATM is a protein subject to O-GlcNAc modification.
• Dynamic O-GlcNAc modification plays a significant role in regulating the ATM-mediated DNA damage response.
• O-GlcNAcylation influences both the activation and recovery phases of ATM signaling.