title: Thr-1989 phosphorylation is a marker of active ataxia telangiectasia-mutated and Rad3-related (ATR) kinase.
abstract: The DNA damage response kinases ataxia telangiectasia-mutated (ATM), DNA-dependent protein kinase (DNA-PK), and ataxia telangiectasia-mutated and Rad3-related (ATR) signal through multiple pathways to promote genome maintenance. These related kinases share similar methods of regulation, including recruitment to specific nucleic acid structures and association with protein activators. ATM and DNA-PK also are regulated via phosphorylation, which provides a convenient biomarker for their activity. Whether phosphorylation regulates ATR is unknown. Here we identify ATR Thr-1989 as a DNA damage-regulated phosphorylation site. Selective inhibition of ATR prevents Thr-1989 phosphorylation, and phosphorylation requires ATR activation. Cells engineered to express only a non-phosphorylatable T1989A mutant exhibit a modest ATR functional defect. Our results suggest that, like ATM and DNA-PK, phosphorylation regulates ATR, and phospho-peptide specific antibodies to Thr-1989 provide a proximal marker of ATR activation.
authors.affiliation: Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Nam
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: Runxiang
authors.initials: R
authors.lastname: Zhao
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: Gloria G
authors.initials: GG
authors.lastname: Glick
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: Carol E
authors.initials: CE
authors.lastname: Bansbach
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: David B
authors.initials: DB
authors.lastname: Friedman
authors.affiliation: Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232; Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232. Electronic address: david.cortez@vanderbilt.edu.
authors.forename: David
authors.initials: D
authors.lastname: Cortez
mesh_terms: D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation / Q000502:physiology; D006801:Humans; D010766:Phosphorylation / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D013912:Threonine / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; D013912:Threonine; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases