Polo-like kinase-1 is a target of the DNA damage checkpoint.
Polo-like kinases (PLKs) have an important role in several stages of mitosis. They contribute to the activation of cyclin B/Cdc2 and are involved in centrosome maturation and bipolar spindle formation at the onset of mitosis. PLKs also control mitotic exit by regulating the anaphase-promoting complex (APC) and have been implicated in the temporal and spatial coordination of cytokinesis. Experiments in budding yeast have shown that the PLK Cdc5 may be controlled by the DNA damage checkpoint. Here we report the effects of DNA damage on Polo-like kinase-1 (Plk1) in a variety of human cell lines. We show that Plk1 is inhibited by DNA damage in G2 and in mitosis. In line with this, we show that DNA damage blocks mitotic exit. DNA damage does not inhibit the kinase activity of Plk1 mutants in which the conserved threonine residue in the T-loop has been changed to aspartic acid, suggesting that DNA damage interferes with the activation of Plk1. Significantly, expression of these mutants can override the G2 arrest induced by DNA damage. On the basis of these data we propose that Plk1 is an important target of the DNA damage checkpoint, enabling cell-cycle arrests at multiple points in G2 and mitosis.
Smits
V A
VA
Jordan Laboratory, Department of Hematology, University Medical Centre Utrecht G 03.647, P.O. Box 85500, 3508 GA Utrecht, The Netherlands.
Klompmaker
R
R
Arnaud
L
L
Rijksen
G
G
Nigg
E A
EA
Medema
R H
RH
D016203:CDC2 Protein Kinase / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D019926:Cyclin B / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D004249:DNA Damage; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007701:Kinetin; D008938:Mitosis; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D011687:Purines / Q000494:pharmacology; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D020687:cdc25 Phosphatases / Q000378:metabolism; D000097869:Polo-Like Kinase 1
D016203:CDC2 Protein Kinase; D018797:Cell Cycle Proteins; D019926:Cyclin B; D018844:Cyclin-Dependent Kinases; D004791:Enzyme Inhibitors; D007701:Kinetin; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D011687:Purines; D020687:cdc25 Phosphatases; D000097869:Polo-Like Kinase 1; C090046:olomoucine; C517009:CDC25C protein, human