title: Characterization of functional domains in human Claspin.
abstract: Claspin is a mediator of the ATR-dependent DNA replication checkpoint in human cells and also promotes DNA replication fork progression and stability. Though Claspin has been shown to bind DNA and co-immunoprecipitate with other replication fork-associated proteins, the specific protein-protein and protein-DNA interactions that are important for Claspin function are not known. We therefore purified several domains of human Claspin and then tested for direct interactions of these fragments with several replication fork-associated proteins and with DNA. Our data show that the N terminus of Claspin binds to the replicative helicase co-factor Cdc45, the Timeless protein and a branched, replication fork-like DNA structure. In contrast, the C terminus of Claspin associates with DNA polymerase epsilon and Rad17-Replication Factor C (RFC). We conclude that multiple protein-DNA and protein-protein interactions may be important for Claspin function during DNA replication and DNA replication checkpoint signaling.
authors.affiliation: University of North Carolina School of Medicine, Chapel Hill, NC USA.
authors.forename: Ozdemirhan
authors.initials: O
authors.lastname: Serçin
authors.forename: Michael G
authors.initials: MG
authors.lastname: Kemp
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism; D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004257:DNA Polymerase II / Q000737:chemistry / Q000378:metabolism; D004261:DNA Replication; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D051818:Replication Protein C / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C113571:CDC45 protein, human; C488158:CLSPN protein, human; D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; C113575:Rad17 protein, human; C509769:TIMELESS protein, human; D004247:DNA; D004257:DNA Polymerase II; D051818:Replication Protein C