title: Function of polo-like kinase 3 in NF-kappaB-mediated proapoptotic response.
abstract: RelA, the p65 subunit of NF-kappaB transcription factors, plays a key role in regulation of antiapoptotic and proapoptotic responses. However, the downstream target genes regulated by RelA-NF-kappaB in the initiation of proapoptotic signaling were not identified. We previously showed that RelA-NF-kappaB functioned as a proapoptotic factor by activating the p53-signaling pathway in response to doxycycline-induced superoxide. In the present study, we demonstrate that the ability of doxycycline/superoxide to induce expression of polo-like kinase 3 (Plk3) depends on NF-kappaB activity. We identified a kappaB binding site in the promoter of Plk3, and this kappaB site is directly involved in its induction by the RelA-NF-kappaB complex. Plk3 formed a complex with p53 and was involved in the phosphorylation of p53 on Ser-20 in response to superoxide. Inhibition of Plk3 expression by Plk3 small interfering RNA suppressed the doxycycline/superoxide-mediated apoptosis. Overexpression of wild-type Plk3 in HCT116 p53+/+ cells induced rapid apoptosis, whereas overexpression of wild-type Plk3 in HCT116 p53-/- cells and the kinase-defective mutant Plk3(K91R) in p53+/+ cells induced delayed onset of apoptosis. Furthermore, mutagenesis of Plk3 showed that the N-terminal domain (amino acids 1-26) is essential for the induction of delay onset of apoptosis. These data show that Plk3 is a RelA-NF-kappaB-regulated gene that induces apoptosis in both p53-dependent and -independent signaling pathways, suggesting a possible mechanism for RelA-NF-kappaB-regulated proapoptotic responses.
authors.affiliation: Department of Surgical Oncology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: Zhongkui
authors.initials: Z
authors.lastname: Li
authors.forename: Jiangong
authors.initials: J
authors.lastname: Niu
authors.forename: Tadashi
authors.initials: T
authors.lastname: Uwagawa
authors.forename: Bailu
authors.initials: B
authors.lastname: Peng
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Chiao
mesh_terms: D017209:Apoptosis; D001665:Binding Sites; D015152:Blotting, Northern; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D050759:Cyclin-Dependent Kinase Inhibitor p21; D053938:DNA Fragmentation; D004318:Doxycycline / Q000494:pharmacology; D005786:Gene Expression Regulation; D016158:Genes, p53; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D008156:Luciferases / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012694:Serine / Q000737:chemistry; D015398:Signal Transduction; D013997:Time Factors; D051996:Transcription Factor RelA; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D000097868:Polo-like Kinases
chemical_list: D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004318:Doxycycline; D020672:I-kappa B Proteins; D008156:Luciferases; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D017346:Protein Serine-Threonine Kinases; D034741:RNA, Small Interfering; D012694:Serine; D051996:Transcription Factor RelA; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C493956:CDKN1A protein, human; C000606204:NFKBIA protein, human; C486256:PLK3 protein, human; D000097868:Polo-like Kinases