title: Phosphorylation of Sp1 in response to DNA damage by ataxia telangiectasia-mutated kinase.
abstract: Sp1, a transcription factor that regulates expression of a wide array of essential genes, contains two SQ/TQ cluster domains, which are characteristic of ATM kinase substrates. ATM substrates are transducers and effectors of the DNA damage response, which involves sensing damage, checkpoint activation, DNA repair, and/or apoptosis. A role for Sp1 in the DNA damage response is supported by our findings: Activation of ATM induces Sp1 phosphorylation with kinetics similar to H2AX; inhibition of ATM activity blocks Sp1 phosphorylation; depletion of Sp1 sensitizes cells to DNA damage and increases the frequency of double strand breaks. We have identified serine 101 as a critical site phosphorylated by ATM; Sp1 with serine 101 mutated to alanine (S101A) is not significantly phosphorylated in response to damage and cannot restore increased sensitivity to DNA damage of cells depleted of Sp1. Together, these data show that Sp1 is a novel ATM substrate that plays a role in the cellular response to DNA damage.
authors.affiliation: Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
authors.forename: Beatrix A
authors.initials: BA
authors.lastname: Olofsson
authors.forename: Crystal M
authors.initials: CM
authors.lastname: Kelly
authors.forename: Jiyoon
authors.initials: J
authors.lastname: Kim
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Hornsby
authors.forename: Jane
authors.initials: J
authors.lastname: Azizkhan-Clifford
mesh_terms: D000595:Amino Acid Sequence; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D002470:Cell Survival / Q000502:physiology; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016877:Oxidants / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism*; D016329:Sp1 Transcription Factor / Q000235:genetics* / Q000378:metabolism*; D013379:Substrate Specificity; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D016877:Oxidants; D016329:Sp1 Transcription Factor; D025521:Tumor Suppressor Proteins; D006861:Hydrogen Peroxide; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases