The DNA damage effector Chk1 kinase regulates Cdc14B nucleolar shuttling during cell cycle progression

Cell Cycle. 2011 Feb 15;10(4):671-9. doi: 10.4161/cc.10.4.14901. Epub 2011 Feb 15.


Chk1 is a critical effector of DNA damage checkpoints necessary for the maintenance of chromosome integrity during cell cycle progression. Here we report, that Chk1 co-localized with the nucleolar marker, fibrillarin in response to radiation-induced DNA damage in human cells. Interestingly, in vitro studies using GST pull down assays identified the dual-specificity serine/threonine nucleolar phosphatase Cdc14B as a Chk1 substrate. Furthermore, Chk1, but not a kinase-dead Chk1 control, was shown to phosphorylate Cdc14B using an in vitro kinase assay. Co-immunoprecipitation experiments using exogenous Cdc14B transfected into human cells confirmed the interaction of Cdc14B and Chk1 during cell cycle. In addition, reduction of Chk1 levels via siRNA or UCN-01 treatment demonstrated that Chk1 activation following DNA damage was required for Cdc14B export from the nucleolus. These studies have revealed a novel interplay between Chk1 kinase and Cdc14B phosphatase involving radiation-induced nucleolar shuttling to facilitate error-free cell cycle progression and prevent genomic instability.

Publication types

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

MeSH terms

  • Blotting, Western
  • Cell Cycle*
  • Cell Line
  • Cell Nucleolus / enzymology
  • Cell Nucleolus / genetics
  • Cell Nucleolus / metabolism*
  • Checkpoint Kinase 1
  • Chromosomal Proteins, Non-Histone / metabolism
  • Chromosomes, Human / genetics
  • Chromosomes, Human / physiology
  • DNA Damage*
  • Dual-Specificity Phosphatases / genetics
  • Dual-Specificity Phosphatases / metabolism*
  • Genomic Instability
  • HeLa Cells
  • Humans
  • Immunoblotting
  • Immunoprecipitation
  • Phosphorylation
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • RNA Interference
  • RNA, Small Interfering
  • Staurosporine / analogs & derivatives
  • Staurosporine / pharmacology


  • Chromosomal Proteins, Non-Histone
  • RNA, Small Interfering
  • fibrillarin
  • 7-hydroxystaurosporine
  • Protein Kinases
  • CHEK1 protein, human
  • Checkpoint Kinase 1
  • Protein Serine-Threonine Kinases
  • CDC14B protein, human
  • Dual-Specificity Phosphatases
  • Staurosporine