title: Cdc5L interacts with ATR and is required for the S-phase cell-cycle checkpoint.
abstract: Cell division cycle 5-like protein (Cdc5L) is a core component of the putative E3 ubiquitin ligase complex containing Prp19/Pso4, Plrg1 and Spf27. This complex has been shown to have a role in pre-messenger RNA splicing from yeast to humans; however, more recent studies have described a function for this complex in the cellular response to DNA damage. Here, we show that Cdc5L interacts physically with the cell-cycle checkpoint kinase ataxia-telangiectasia and Rad3-related (ATR). Depletion of Cdc5L by RNA-mediated interference methods results in a defective S-phase cell-cycle checkpoint and cellular sensitivity in response to replication-fork blocking agents. Furthermore, we show that Cdc5L is required for the activation of downstream effectors or mediators of ATR checkpoint function such as checkpoint kinase 1 (Chk1), cell cycle checkpoint protein Rad 17 (Rad17) and Fanconi anaemia complementation group D2 protein (FancD2). In addition, we have mapped the ATR-binding region in Cdc5L and show that a deletion mutant that is unable to interact with ATR is defective in the rescue of the checkpoint deficiency in Cdc5L-depleted cells. These findings show a new function for Cdc5L in the regulation of the ATR-mediated cell-cycle checkpoint in response to genotoxic agents.
authors.affiliation: Department of Genetics, The University of Texas MD Anderson Cancer Center, University of Texas, 1515 Holcombe Boulevard, Houston, Texas 77030, USA.
authors.forename: Nianxiang
authors.initials: N
authors.lastname: Zhang
authors.forename: Ramandeep
authors.initials: R
authors.lastname: Kaur
authors.forename: Shamima
authors.initials: S
authors.lastname: Akhter
authors.forename: Randy J
authors.initials: RJ
authors.lastname: Legerski
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004249:DNA Damage; D006801:Humans; D009154:Mutation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016196:S Phase
chemical_list: C508357:CDC5L protein, human; D018797:Cell Cycle Proteins; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases