AMPK regulates histone H2B O-GlcNAcylation.

Area of Science:

• Epigenetics
• Molecular Biology
• Cellular Metabolism

Background:

• Histone H2B O-GlcNAcylation is a key epigenetic modification regulating gene transcription.
• The precise regulatory mechanisms governing histone O-GlcNAcylation remain largely unknown.
• Understanding these mechanisms is crucial for deciphering cellular responses to nutrient availability.

Purpose of the Study:

• To investigate the regulatory pathways controlling histone H2B O-GlcNAcylation.
• To elucidate the role of adenosine-monophosphate-activated protein kinase (AMPK) in this process.
• To uncover the interplay between AMPK and O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT).

Main Methods:

• Phosphorylation assays to determine the effect of AMPK on OGT.
• Chromatin immunoprecipitation to assess OGT-chromatin association.
• Quantitative analysis of histone H2B O-GlcNAcylation levels.
• Gene transcription assays.

Main Results:

• AMPK directly phosphorylates OGT, inhibiting its association with chromatin.
• This phosphorylation suppresses histone H2B O-GlcNAcylation and gene transcription.
• OGT reciprocally O-GlcNAcylates AMPK, enhancing its activity, establishing a feedback loop.
• A crosstalk between LKB1-AMPK and hexosamine biosynthesis (HBP)-OGT pathways was identified.

Conclusions:

• AMPK acts as a negative regulator of histone H2B O-GlcNAcylation.
• The identified feedback loop integrates nutrient sensing with epigenetic regulation of gene transcription.
• This crosstalk is vital for coordinating cellular metabolic status with transcriptional output.