title: O-GlcNAc modification affects the ATM-mediated DNA damage response.
abstract: BACKGROUND
  O-Linked β-N-acetylglucosamine (O-GlcNAc) is a reversible, post-translational, and regulatory modification of nuclear, mitochondrial, and cytoplasmic proteins that is responsive to cellular stress. The role of O-GlcNAcylation in the ataxia-telangiectasia mutated (ATM)-mediated DNA damage response is unknown. It is unclear whether ATM, which is an early acting and central component of the signal transduction system activated by DNA double strand breaks, is an O-GlcNAc-modified protein.
  
  
  METHODS
  The effect of O-GlcNAc modification on ATM activation was examined using two inhibitors, PUGNAc and DON that increase and decrease, respectively, levels of protein O-GlcNAcylation. To assess O-GlcNAcylation of ATM, immunoprecipitation and immunoblot analyses using anti-ATM or anti-O-GlcNAc antibody were performed in HeLa cells and primary cultured neurons. Interaction of ATM with O-GlcNAc transferase (OGT), the enzyme that adds O-GlcNAc to target proteins, was examined by immunoprecipitation and immunoblot analyses using anti-ATM.
  
  
  RESULTS
  Enhancement of protein O-GlcNAcylation increased levels of X-irradiation-induced ATM activation. However, decreases in protein O-GlcNAcylation did not affect levels of ATM activation, but these decreases did delay ATM activation and ATM recovery processes based on assessment of de-phosphorylation of phospho-ATM. Thus, activation and recovery of ATM were affected by O-GlcNAcylation. ATM was subjected to O-GlcNAcylation, and ATM interacted with OGT. The steady-state O-GlcNAc level of ATM was not significantly responsive to X-irradiation or oxidative stress.
  
  
  CONCLUSIONS
  ATM is an O-GlcNAc modified protein, and dynamic O-GlcNAc modification affects the ATM-mediated DNA damage response.
authors: Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo 173-0015, Japan. miura@tmig.or.jp
authors: Yuri
authors: Y
authors: Miura
authors: Yoko
authors: Y
authors: Sakurai
authors: Tamao
authors: T
authors: Endo
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism* / Q000502:physiology*; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D004249:DNA Damage / Q000502:physiology*; D004260:DNA Repair / Q000502:physiology; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D004622:Embryo, Mammalian; D004789:Enzyme Activation; D006031:Glycosylation; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008813:Mice, Inbred ICR; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D025521:Tumor Suppressor Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; D017351:N-Acetylglucosaminyltransferases; C449880:O-GlcNAc transferase; D010770:Phosphotransferases; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D017346:Protein Serine-Threonine Kinases; D000117:Acetylglucosamine