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Claspin: Timing the Cell Cycle Arrest When the Genome is Damaged
Raimundo Freire, Marcel A.T.M. van Vugt, Ivan Mamely and Rene Medema
volume 5 | issue 24
15 december 2006Pages: 2831 - 2834
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DNA damage checkpoints maintain genomic integrity by delaying cell cycle progression in response to genotoxic stress and stalled replication forks. One central pathway in the checkpoint response is the ATR-Chk1 pathway, in which, upon DNA damage, ATR phosphorylates and activates the effector kinase Chk1. This process depends on the adaptor protein Claspin that bridges ATR and Chk1. Once the damage is repaired, this pathway must somehow be switched off to allow the cell to continue the cell division process, an event known as checkpoint recovery. Polo-like kinase 1 (Plk1) plays a central role during checkpoint recovery. Interestingly, the Xenopus homologue of Plk1, Plx1, is able to bind and phosphorylate Claspin, releasing it from DNA and thereby contributing to Chk1 inactivation. Moreover, it was recently demonstrated that Claspin levels are controlled by proteasomal degradation, and this is regulated by Plk1. Importantly, Plk1-mediated proteosomal degradation of Claspin appears to be essential for checkpoint recovery. Here we review these recent findings and discuss the mechanisms of checkpoint regulation by Claspin.
Authors
Raimundo Freire
1Unidad de Investigación, Hospital Universitario de Canarias; Tenerife, Spain
Marcel A.T.M. van Vugt
Center for Cancer Research, MIT; Cambridge, MA USA
Ivan Mamely
Unidad de Investigación, Hospital Universitario de Canarias; Tenerife, Spain
Rene Medema
UMC Utrecht; Utrech, the Netherlands
We now provide open access to journal articles published online for one year or more. This article may be downloaded at the following link:
Download PDF If the document does not open, please right-click on the link (control-click on a Macintosh) and select the option to save the file to disk.