Cdc5L interacts with ATR and is required for the S-phase cell-cycle checkpoint

EMBO Rep. 2009 Sep;10(9):1029-35. doi: 10.1038/embor.2009.122. Epub 2009 Jul 24.


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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Ataxia Telangiectasia Mutated Proteins
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Line
  • DNA Damage
  • Humans
  • Mutation
  • Protein Binding
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • RNA, Small Interfering / genetics
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • S Phase*


  • CDC5L protein, human
  • Cell Cycle Proteins
  • RNA, Small Interfering
  • RNA-Binding Proteins
  • ATR protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • Protein Serine-Threonine Kinases