ATM regulates NF-κB-dependent immediate-early genes via RelA Ser 276 phosphorylation coupled to CDK9 promoter recruitment

Nucleic Acids Res. 2014 Jul;42(13):8416-32. doi: 10.1093/nar/gku529. Epub 2014 Jun 23.

Abstract

Ataxia-telangiectasia mutated (ATM), a member of the phosphatidylinositol 3 kinase-like kinase family, is a master regulator of the double strand DNA break-repair pathway after genotoxic stress. Here, we found ATM serves as an essential regulator of TNF-induced NF-kB pathway. We observed that TNF exposure of cells rapidly induced DNA double strand breaks and activates ATM. TNF-induced ROS promote nuclear IKKγ association with ubiquitin and its complex formation with ATM for nuclear export. Activated cytoplasmic ATM is involved in the selective recruitment of the E3-ubiquitin ligase β-TrCP to phospho-IκBα proteosomal degradation. Importantly, ATM binds and activates the catalytic subunit of protein kinase A (PKAc), ribosmal S6 kinase that controls RelA Ser 276 phosphorylation. In ATM knockdown cells, TNF-induced RelA Ser 276 phosphorylation is significantly decreased. We further observed decreased binding and recruitment of the transcriptional elongation complex containing cyclin dependent kinase-9 (CDK9; a kinase necessary for triggering transcriptional elongation) to promoters of NF-κB-dependent immediate-early cytokine genes, in ATM knockdown cells. We conclude that ATM is a nuclear damage-response signal modulator of TNF-induced NF-κB activation that plays a key scaffolding role in IκBα degradation and RelA Ser 276 phosphorylation. Our study provides a mechanistic explanation of decreased innate immune response associated with A-T mutation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Ataxia Telangiectasia Mutated Proteins / metabolism*
  • Cell Line
  • Cell Nucleus / metabolism
  • Cyclic AMP-Dependent Protein Kinase Catalytic Subunits / metabolism
  • Cyclin-Dependent Kinase 9 / genetics*
  • Cytokines / genetics
  • Cytokines / metabolism
  • Gene Expression Regulation*
  • Genes, Immediate-Early*
  • Humans
  • I-kappa B Kinase / metabolism
  • I-kappa B Proteins / metabolism
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / metabolism*
  • Phosphorylation
  • Promoter Regions, Genetic
  • Serine / metabolism
  • Transcription Factor RelA / chemistry
  • Transcription Factor RelA / metabolism*
  • Tumor Necrosis Factor-alpha / pharmacology
  • Ubiquitination
  • beta-Transducin Repeat-Containing Proteins / metabolism

Substances

  • Cytokines
  • I-kappa B Proteins
  • NF-kappa B
  • NFKBIA protein, human
  • Transcription Factor RelA
  • Tumor Necrosis Factor-alpha
  • beta-Transducin Repeat-Containing Proteins
  • NF-KappaB Inhibitor alpha
  • Serine
  • Ataxia Telangiectasia Mutated Proteins
  • I-kappa B Kinase
  • Cyclic AMP-Dependent Protein Kinase Catalytic Subunits
  • Cyclin-Dependent Kinase 9