title: Chk1 and Claspin potentiate PCNA ubiquitination.
abstract: Chk1 is a kinase crucial for genomic integrity and an effector of ATR (ATM and Rad3-related) in DNA damage response. Here, we show that Chk1 regulates the DNA damage-induced ubiquitination of proliferating cell nuclear antigen (PCNA), which facilitates the continuous replication of damaged DNA. Surprisingly, this Chk1 function requires the DNA replication protein Claspin but not ATR. Claspin, which is stabilized by Chk1, regulates the binding of the ubiquitin ligase Rad18 to chromatin. Timeless, a Claspin-associating protein, is also required for efficient PCNA ubiquitination. Thus, Chk1 and the Claspin-Timeless module of replication forks not only participate in ATR signaling, but also protect stressed forks independently of ATR.
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Xiaohong H
authors.initials: XH
authors.lastname: Yang
authors.forename: Bunsyo
authors.initials: B
authors.lastname: Shiotani
authors.forename: Marie
authors.initials: M
authors.lastname: Classon
authors.forename: Lee
authors.initials: L
authors.lastname: Zou
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D064007:Ataxia Telangiectasia Mutated Proteins; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D004261:DNA Replication / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011753:Pyrones / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D014162:Transfection; D054875:Ubiquitination / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: C495818:2-morpholin-4-yl-6-thianthren-1-yl-pyran-4-one; D048868:Adaptor Proteins, Signal Transducing; C488158:CLSPN protein, human; D018797:Cell Cycle Proteins; D009025:Morpholines; D018809:Proliferating Cell Nuclear Antigen; D011753:Pyrones; D034741:RNA, Small Interfering; D011494:Protein Kinases; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases; D006918:Hydroxyurea