• Register
X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

X

Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.

No
Yes

Regulation of Chk1 includes chromatin association and 14-3-3 binding following phosphorylation on Ser-345.

Checkpoints are biochemical pathways that provide the cell with mechanisms to detect DNA damage and respond by arresting the cell cycle to allow DNA repair. The conserved checkpoint kinase Chk1 regulates mitotic progression in response to DNA damage and replication interference by blocking the activation of Cdk1/cyclin B. Chk1 is phosphorylated on Ser-317 and Ser-345 following a checkpoint signal, a process that is regulated by Atr, and by the sensor complexes containing Rad17 and Hus1. We show that Chk1 is associated with chromatin in cycling cells and that the chromatin-associated Chk1 is phosphorylated in the absence of exogenous DNA damage. The UV-induced Ser-345-phosphorylated forms of Chk1 that appear minutes after treatment are predominantly associated with chromatin. The Ser-345 site is in a 14-3-3 consensus binding motif and is required for nuclear retention of Chk1 following an hydroxyurea-induced checkpoint signal; nonetheless, Ser-345 or Ser-317 are not required for the chromatin association of Chk1. Hus1, a member of the proliferating cell nuclear antigen-like damage recognition complex plays a role in the phosphorylation of Chk1 on Ser-345, however, Hus1 is not required for phosphorylation on Ser-317 or for Chk1 localization to chromatin. These results indicate that there is more than one step in Chk1 activation and that the regulation of this checkpoint signaling is achieved at least in part through phosphorylation of Ser-345, which serves to localize Chk1 in the nucleus presumably by blocking Crm1-dependent nuclear export.

Pubmed ID: 12676962

Authors

  • Jiang K
  • Pereira E
  • Maxfield M
  • Russell B
  • Goudelock DM
  • Sanchez Y

Journal

The Journal of biological chemistry

Publication Data

July 4, 2003

Associated Grants

  • Agency: NIEHS NIH HHS, Id: P30 ES06096
  • Agency: NCI NIH HHS, Id: R01 CA84463

Mesh Terms

  • 14-3-3 Proteins
  • Cell Cycle
  • Chromatin
  • HeLa Cells
  • Humans
  • Phosphorylation
  • Protein Kinases
  • Serine
  • Tyrosine 3-Monooxygenase