title: Regulation of Polo-like kinase 1 by DNA damage in mitosis. Inhibition of mitotic PLK-1 by protein phosphatase 2A.
abstract: DNA damage triggers multiple checkpoint pathways to arrest cell cycle progression. Polo-like kinase 1 (Plk1) is an important regulator of several events during mitosis. In addition to Plk1 functions in cell cycle, Plk1 is involved in DNA damage check-point in G2 phase. Normally, ataxia telangiectasia-mutated kinase (ATM) is a key enzyme involved in G2 phase cell cycle arrest following DNA damage, and inhibition of Plk1 by DNA damage during G2 occurs in a ATM/ATR-dependent manner. However, it is still unclear how Plk1 is regulated in response to DNA damage in mitosis in which Plk1 is already activated. Here, we show that treatment of mitotic cells with doxorubicin and gamma-irradiation inhibits Plk1 activity through dephosphorylation of Plk1, and cells were arrested in G2 phase. Treatments of the phosphatase inhibitors and siRNA experiments suggested that PP2A pathway might be involved in regulating mitotic Plk1 activity in mitotic DNA damage. Finally, we propose a novel pathway, which is connected between ATM/ATR/Chk and protein phosphatase-Plk1 in DNA damage response in mitosis.
authors.affiliation: Laboratory of Biochemistry, The School of Dentistry, Dankook University, 29 Anseo-Dong, Cheonan, 330-714, Korea. yjjang@dku.edu
authors.forename: Young-Joo
authors.initials: YJ
authors.lastname: Jang
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Ji
authors.forename: Young-Chul
authors.initials: YC
authors.lastname: Choi
authors.forename: Chun Jeih
authors.initials: CJ
authors.lastname: Ryu
authors.forename: Seon-Yle
authors.initials: SY
authors.lastname: Ko
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D064447:Checkpoint Kinase 2; D004249:DNA Damage; D004789:Enzyme Activation; D016195:G2 Phase / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D054648:Protein Phosphatase 2; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D015398:Signal Transduction; D000097869:Polo-Like Kinase 1
chemical_list: D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D064447:Checkpoint Kinase 2; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D000097869:Polo-Like Kinase 1; C576597:ATR protein, human; C578634:CHEK2 protein, human