Phosphorylation of Plk1 at S137 and T210 is inhibited in response to DNA damage.
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.
Tsvetkov
Lyuben
L
Department of Pathology, School of Medicine, Yale University, New Haven, Connecticut 06510, USA. lyuben.tsvetkov@yale.edu
Stern
David F
DF
D064007:Ataxia Telangiectasia Mutated Proteins; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002110:Caffeine / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D019926:Cyclin B / Q000502:physiology; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D004789:Enzyme Activation; D016195:G2 Phase / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008938:Mitosis / Q000187:drug effects / Q000502:physiology*; D015739:Nocodazole / Q000494:pharmacology; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000378:metabolism*; D012694:Serine / Q000032:analysis*; D015398:Signal Transduction / Q000502:physiology; D019311:Staurosporine / Q000031:analogs & derivatives / Q000494:pharmacology; D013912:Threonine / Q000032:analysis*; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D020687:cdc25 Phosphatases / Q000502:physiology; D000097869:Polo-Like Kinase 1
D064007:Ataxia Telangiectasia Mutated Proteins; D016203:CDC2 Protein Kinase; D002110:Caffeine; D018797:Cell Cycle Proteins; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D019926:Cyclin B; D004268:DNA-Binding Proteins; D004317:Doxorubicin; D015739:Nocodazole; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D012694:Serine; D019311:Staurosporine; D013912:Threonine; D025521:Tumor Suppressor Proteins; D020687:cdc25 Phosphatases; D000097869:Polo-Like Kinase 1; C054852:7-hydroxystaurosporine; C576324:ATM protein, human; C576597:ATR protein, human; C000605867:CHEK1 protein, human; C578634:CHEK2 protein, human; C517009:CDC25C protein, human