title: Dpb11 activates the Mec1-Ddc2 complex.
abstract: The Saccharomyces cerevisiae Mec1-Ddc2 checkpoint kinase complex (the ortholog to human ATR-ATRIP) is an essential regulator of genomic integrity. The S. cerevisiae BRCT repeat protein Dpb11 functions in the initiation of both DNA replication and cell cycle checkpoints. Here, we report a genetic and physical interaction between Dpb11 and Mec1-Ddc2. A C-terminal domain of Dpb11 is sufficient to associate with Mec1-Ddc2 and strongly stimulates the kinase activity of Mec1 in a Ddc2-dependent manner. Furthermore, Mec1 phosphorylates Dpb11 and thereby amplifies the stimulating effect of Dpb11 on Mec1-Ddc2 kinase activity. Thus, Dpb11 is a functional ortholog of human TopBP1, and the Mec1/ATR activation mechanism is conserved from yeast to humans.
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Mordes
authors.forename: Edward A
authors.initials: EA
authors.lastname: Nam
authors.forename: David
authors.initials: D
authors.lastname: Cortez
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D004789:Enzyme Activation; D006801:Humans; D006918:Hydroxyurea / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D019384:Nucleic Acid Synthesis Inhibitors / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; C097185:DPB11 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; C440014:LCD1 protein, S cerevisiae; D019384:Nucleic Acid Synthesis Inhibitors; D010750:Phosphoproteins; D029701:Saccharomyces cerevisiae Proteins; C088937:MEC1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D006918:Hydroxyurea