title: Structure and function of the Rad9-binding region of the DNA-damage checkpoint adaptor TopBP1.
abstract: TopBP1 is a scaffold protein that coordinates activation of the DNA-damage-checkpoint response by coupling binding of the 9-1-1 checkpoint clamp at sites of ssDNA, to activation of the ATR-ATRIP checkpoint kinase complex. We have now determined the crystal structure of the N-terminal region of human TopBP1, revealing an unexpected triple-BRCT domain structure. The arrangement of the BRCT domains differs significantly from previously described tandem BRCT domain structures, and presents two distinct sites for binding phosphopeptides in the second and third BRCT domains. We show that the site in the second but not third BRCT domain in the N-terminus of TopBP1, provides specific interaction with a phosphorylated motif at pSer387 in Rad9, which can be generated by CK2.
authors: Cancer Research UK DNA Repair Enzyme Group, Section of Structural Biology, The Institute of Cancer Research, London, UK.
authors: Mathieu
authors: M
authors: Rappas
authors: Antony W
authors: AW
authors: Oliver
authors: Laurence H
authors: LH
authors: Pearl
mesh_terms: D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism; D010748:Phosphopeptides / Q000737:chemistry; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010748:Phosphopeptides; C110513:TOPBP1 protein, human; C069930:rad9 protein