title: Polo-like kinase 1 (Plk1) inhibits p53 function by physical interaction and phosphorylation.
abstract: Polo-like kinase 1 (Plk1) has an important role in the regulation of M phase of the cell cycle. In addition to its cell cycle-regulatory function, Plk1 has a potential role in tumorigenesis. Here we found for the first time that Plk1 physically binds to the tumor suppressor p53 in mammalian cultured cells, and inhibits its transactivation activity as well as its pro-apoptotic function. During the cisplatin-induced apoptosis in human neuroblastoma SH-SY5Y cells, the expression level of Plk1 was significantly decreased both at mRNA and protein levels, whereas cisplatin treatment caused a remarkable stabilization of p53. Systematic immunoprecipitation analyses using a series of deletion mutants of p53 revealed that a sequence-specific DNA-binding region of p53 is required and sufficient for the physical interaction with Plk1. The ectopically overexpressed Plk1 was co-localized with the endogenous p53 in mammalian cell nucleus, as shown by confocal laser microscopy. Expression of exogenous Plk1 and p53 in p53-deficient lung carcinoma H1299 cells greatly decreased the p53-mediated transcription from the p53-responsive p21(WAF1), MDM2, and BAX promoters, whereas the kinase-deficient mutant form of Plk1 failed to reduce the transcriptional activity of p53. Consistent with the luciferase reporter analysis, Plk1 had an ability to block the p53-dependent induction of the endogenous p21(WAF1). In addition, Plk1 inhibited the pro-apoptotic function of p53 in H1299 cells. Intriguingly, Plk1-mediated repression of p53 was attenuated with ATM. Thus, our present findings strongly suggest that p53 is a critical target of Plk1, and its function is abrogated through the physical interaction with Plk1.
authors.affiliation: Division of Biochemistry, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan.
authors.forename: Kiyohiro
authors.initials: K
authors.lastname: Ando
authors.forename: Toshinori
authors.initials: T
authors.lastname: Ozaki
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Kazushige
authors.initials: K
authors.lastname: Furuya
authors.forename: Mitsuchika
authors.initials: M
authors.lastname: Hosoda
authors.forename: Syunji
authors.initials: S
authors.lastname: Hayashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fukuzawa
authors.forename: Akira
authors.initials: A
authors.lastname: Nakagawara
mesh_terms: D000818:Animals; D017209:Apoptosis; D064007:Ataxia Telangiectasia Mutated Proteins; D001665:Binding Sites; D019556:COS Cells; D018797:Cell Cycle Proteins / Q000502:physiology; D002522:Chlorocebus aethiops; D002945:Cisplatin / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D004249:DNA Damage; D004268:DNA-Binding Proteins; D006801:Humans; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D011518:Proto-Oncogene Proteins; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000502:physiology*; D025521:Tumor Suppressor Proteins; D000097869:Polo-Like Kinase 1; D000097868:Polo-like Kinases
chemical_list: D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D002945:Cisplatin; D004247:DNA; D004268:DNA-Binding Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D000097869:Polo-Like Kinase 1; C486256:PLK3 protein, human; D000097868:Polo-like Kinases; C576324:ATM protein, human