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Brief Report
Cdc2 Tyrosine Phosphorylation is Not Required for the S-Phase DNA Damage Checkpoint in Fission Yeast
Naveen Kommajosyula and Nick Rhind
volume 5 | issue 21
1 november 2006Pages: 2495 - 2500
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The S-phase DNA damage checkpoint slows replication when damage occurs during S phase. Cdc25, which activates Cdc2 by dephosphorylating tyrosine-15, has been shown to be a downstream target of the checkpoint in metazoans, but its role is not clear in fission yeast. The dephosphorylation of Cdc2 has been assumed not to play a role in S-phase regulation because cells replicate in the absence of Cdc25, demonstrating that tyrosine-15 phosphorylated Cdc2 is sufficient for S phase. However, it has been reported recently that Cdc25 is required for the slowing of S phase in response to damage in fission yeast, suggesting a modulatory role for Cdc2 dephosphorylation in S phase. We have investigated the role of Cdc25 and the tyrosine phosphorylation of Cdc2 in the S-phase damage checkpoint, and our results show that Cdc2 phosphorylation is not a target of the checkpoint. The checkpoint was not compromised in a Cdc25 overexpressing strain, a strain carrying non-phosphorylatable form of Cdc2, or in a strain lacking Cdc25. Our results are consistent with a strictly Cdc2-Y15 phosphorylation-independent mechanism of the fission yeast S-phase DNA damage checkpoint.
Authors
Naveen Kommajosyula
University of Massachusetts Medical School, Worcester, MA
Nick Rhind
UMass Med School
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.