title: Interaction of Chk1 with Treslin negatively regulates the initiation of chromosomal DNA replication.
abstract: Treslin helps to trigger the initiation of DNA replication by promoting integration of Cdc45 into the replicative helicase. Treslin is a key positive-regulatory target of cell-cycle control mechanisms; activation of Treslin by cyclin-dependent kinase is essential for the initiation of replication. Here we demonstrate that Treslin is also a critical locus for negative regulatory mechanisms that suppress initiation. We found that the checkpoint-regulatory kinase Chk1 associates specifically with a C-terminal domain of Treslin (designated TRCT). Mutations in the TRCT domain abolish binding of Chk1 to Treslin and thereby eliminate Chk1-catalyzed phosphorylation of Treslin. Significantly, abolition of the Treslin-Chk1 interaction results in elevated initiation of chromosomal DNA replication during an unperturbed cell cycle, which reveals a function for Chk1 during a normal S phase. This increase is due to enhanced loading of Cdc45 onto potential replication origins. These studies provide important insights into how vertebrate cells orchestrate proper initiation of replication.
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Cai
authors.initials: C
authors.lastname: Guo
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Akiko
authors.initials: A
authors.lastname: Kumagai
authors.affiliation: Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA 90095, USA; Developmental Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Katharina
authors.initials: K
authors.lastname: Schlacher
authors.affiliation: Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Shevchenko
authors.affiliation: Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
authors.forename: Andrej
authors.initials: A
authors.lastname: Shevchenko
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA. Electronic address: dunphy@caltech.edu.
authors.forename: William G
authors.initials: WG
authors.lastname: Dunphy
mesh_terms: D000818:Animals; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D002875:Chromosomes / Q000378:metabolism; D004261:DNA Replication; D057809:HEK293 Cells; D006801:Humans; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics / Q000378:metabolism*
chemical_list: C113571:CDC45 protein, human; C502211:Cdc45 protein, Xenopus; D018797:Cell Cycle Proteins; C547407:TICRR protein, Xenopus; C547406:TICRR protein, human; D029867:Xenopus Proteins; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000605875:Chek1 protein, Xenopus