title: Regulation of DNA replication through Sld3-Dpb11 interaction is conserved from yeast to humans.
abstract: Cyclin-dependent kinases (CDKs) play crucial roles in promoting DNA replication and preventing rereplication in eukaryotic cells [1-4]. In budding yeast, CDKs promote DNA replication by phosphorylating two proteins, Sld2 and Sld3, which generates binding sites for pairs of BRCT repeats (breast cancer gene 1 [BRCA1] C terminal repeats) in the Dpb11 protein [5, 6]. The Sld3-Dpb11-Sld2 complex generated by CDK phosphorylation is required for the assembly and activation of the Cdc45-Mcm2-7-GINS (CMG) replicative helicase. In response to DNA replication stress, the interaction between Sld3 and Dpb11 is blocked by the checkpoint kinase Rad53 [7], which prevents late origin firing [7, 8]. Here we show that the two key CDK sites in Sld3 are conserved in the human Sld3-related protein Treslin/ticrr and are essential for DNA replication. Moreover, phosphorylation of these two sites mediates interaction with the orthologous pair of BRCT repeats in the human Dpb11 ortholog, TopBP1. Finally, we show that DNA replication stress prevents the interaction between Treslin/ticrr and TopBP1 via the Chk1 checkpoint kinase. Our results indicate that Treslin/ticrr is a genuine ortholog of Sld3 and that the Sld3-Dpb11 interaction has remained a critical nexus of S phase regulation through eukaryotic evolution.
authors.affiliation: Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, UK.
authors.forename: Dominik
authors.initials: D
authors.lastname: Boos
authors.forename: Luis
authors.initials: L
authors.lastname: Sanchez-Pulido
authors.forename: Mathieu
authors.initials: M
authors.lastname: Rappas
authors.forename: Laurence H
authors.initials: LH
authors.lastname: Pearl
authors.forename: Antony W
authors.initials: AW
authors.lastname: Oliver
authors.forename: Chris P
authors.initials: CP
authors.lastname: Ponting
authors.forename: John F X
authors.initials: JF
authors.lastname: Diffley
mesh_terms: D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D000071877:Checkpoint Kinase 1; D017124:Conserved Sequence; D018844:Cyclin-Dependent Kinases / Q000737:chemistry / Q000502:physiology; D004261:DNA Replication / Q000502:physiology*; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000378:metabolism / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D016415:Sequence Alignment; D015003:Yeasts / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins; C097185:DPB11 protein, S cerevisiae; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; C547406:TICRR protein, human; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D018844:Cyclin-Dependent Kinases