Sign up for Table of Contents Alerts.
Email this page
Print this page
Report
Phosphorylation of Plk1 at S137 and T210 is Inhibited in Response to DNA Damage
Lyuben Tsvetkov and David F. Stern
volume 4 | issue 1
january 2005Pages: 166 - 171
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.
Polo-like kinase 1 (Plk1) regulates multiple processes during mitosis. Plk1 is activated by phosphorylation at the G2/M phase boundary. Active Plk1 is involved in promotion of mitotic entry through activation of Cdc25C, and through nuclear import of cyclin B1 that together activate Cdc2/cyclin B kinase. In earlier work, phosphopeptide mapping identified several phosphorylation sites in Plk1. Mutational analysis pinpointed threonine 210, which is located in the activation loop of the kinase domain, as the major activation site of Plk1. In response to DNA damage, ATM/ATR-dependent checkpoint pathways inhibit Plk1 activity. Insensitivity of Plk1T210D, a constitutively active mutant, to DNA damage-induced inhibition of Plk1 indicates that regulation of Plk1 phosphorylation is a potential target of DNA damage checkpoints. In the present paper, we report that in vivo phosphorylation of Plk1 at serine 137 (S137) and threonine 210 (T210) occurs in mitosis. DNA damage prevents phosphorylation of Plk1 at both S137 and T210 in asynchronous cells but not in mitotic cells. Inhibitors of ATM/ATR and Chk1/Chk2 protein kinases avert the inhibition of Plk1 phosphorylation in response to DNA damage. These data suggest a participation of DNA damage checkpoints in regulation of the signaling pathways upstream of Plk1.
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.