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Bunch H, Kim D, Naganuma M, Nakagawa R, Cong A, Jeong J, Ehara H, Vu H, Chang JH, Schellenberg MJ, Sekine SI. ERK2-topoisomerase II regulatory axis is important for gene activation in immediate early genes. Nat Commun 2023; 14:8341. [PMID: 38097570 PMCID: PMC10721843 DOI: 10.1038/s41467-023-44089-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 11/29/2023] [Indexed: 12/17/2023] Open
Abstract
The function of the mitogen-activated protein kinase signaling pathway is required for the activation of immediate early genes (IEGs), including EGR1 and FOS, for cell growth and proliferation. Recent studies have identified topoisomerase II (TOP2) as one of the important regulators of the transcriptional activation of IEGs. However, the mechanism underlying transcriptional regulation involving TOP2 in IEG activation has remained unknown. Here, we demonstrate that ERK2, but not ERK1, is important for IEG transcriptional activation and report a critical ELK1 binding sequence for ERK2 function at the EGR1 gene. Our data indicate that both ERK1 and ERK2 extensively phosphorylate the C-terminal domain of TOP2B at mutual and distinctive residues. Although both ERK1 and ERK2 enhance the catalytic rate of TOP2B required to relax positive DNA supercoiling, ERK2 delays TOP2B catalysis of negative DNA supercoiling. In addition, ERK1 may relax DNA supercoiling by itself. ERK2 catalytic inhibition or knock-down interferes with transcription and deregulates TOP2B in IEGs. Furthermore, we present the first cryo-EM structure of the human cell-purified TOP2B and etoposide together with the EGR1 transcriptional start site (-30 to +20) that has the strongest affinity to TOP2B within -423 to +332. The structure shows TOP2B-mediated breakage and dramatic bending of the DNA. Transcription is activated by etoposide, while it is inhibited by ICRF193 at EGR1 and FOS, suggesting that TOP2B-mediated DNA break to favor transcriptional activation. Taken together, this study suggests that activated ERK2 phosphorylates TOP2B to regulate TOP2-DNA interactions and favor transcriptional activation in IEGs. We propose that TOP2B association, catalysis, and dissociation on its substrate DNA are important processes for regulating transcription and that ERK2-mediated TOP2B phosphorylation may be key for the catalysis and dissociation steps.
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Affiliation(s)
- Heeyoun Bunch
- Department of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea.
- School of Applied Biosciences, College of Agriculture & Life Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea.
| | - Deukyeong Kim
- School of Applied Biosciences, College of Agriculture & Life Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Masahiro Naganuma
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Reiko Nakagawa
- RIKEN BDR Laboratory for Phyloinformatics, Hyogo, 650-0047, Japan
| | - Anh Cong
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jaehyeon Jeong
- Department of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Haruhiko Ehara
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Hongha Vu
- Department of Biology Education, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Jeong Ho Chang
- Department of Biology Education, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Matthew J Schellenberg
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Shun-Ichi Sekine
- Laboratory for Transcription Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
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2
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Kammari K, Devaraya K, Swain S, Kondapi AK. The topoisomerase II β -kinase associated with HIV-1 is a potential target for pyridine-bischalcones' anti-HIV-1 activity. Eur J Med Chem 2023; 259:115623. [PMID: 37473689 DOI: 10.1016/j.ejmech.2023.115623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/15/2023] [Accepted: 07/03/2023] [Indexed: 07/22/2023]
Abstract
Topoisomerase II (TopoII) is a critical component of HIV-1 integration, proviral DNA synthesis, and reverse transcription. During HIV-1 infection, the TopoIIβkinase (TopoIIβKHIV-1) phosphorylates TopoIIβ. Our earlier research demonstrated that the pyridine scaffold has potent anti-HIV-1 activity by specifically inhibiting TopoIIβKHIV-1 activity. 3D QSAR results showed the presence of molecular features for interaction with TopoIIβKHIV-1 requiring chemically induced proximity for potential interaction. In this study, the chalcone and methyl groups were added to the pyridine scaffold's core to achieve the desired proximity length between the pyridine scaffold and charged centers, which resulted in an inhibitory activity against TopoIIβKHIV-1 and viral replication. According to the findings, the TopoIIβKHIV-1activity was inhibited by the inclusion of the pyridine scaffold with the chalcone group, leading to better anti-HIV-1 activity. The water-soluble methylated pyridinium chalcones' showed significant TopoIIβKHIV-1 antagonism, anti-HIV-1 activity (from IC50 > 500 nM to ID50 25 nM), and reduced cytotoxicity (CC50 = 2 mM). These activities could be associated with the charge on the pyridine and extended proximity. Therefore, it is clear that within the scope of this work, altering the proximity length and charge centers of pyridine molecules are critical for the design and development of effective anti-HIV-1 leads, specifically targeting TopoIIβKHIV-1.
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Affiliation(s)
- Kurumurthy Kammari
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, India
| | - Kiran Devaraya
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, India
| | - Sarita Swain
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, India
| | - Anand K Kondapi
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, India.
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3
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Ling EM, Baslé A, Cowell IG, van den Berg B, Blower TR, Austin CA. A comprehensive structural analysis of the ATPase domain of human DNA topoisomerase II beta bound to AMPPNP, ADP, and the bisdioxopiperazine, ICRF193. Structure 2022; 30:1129-1145.e3. [PMID: 35660158 PMCID: PMC9592559 DOI: 10.1016/j.str.2022.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/25/2022] [Accepted: 05/10/2022] [Indexed: 11/16/2022]
Abstract
Human topoisomerase II beta (TOP2B) modulates DNA topology using energy from ATP hydrolysis. To investigate the conformational changes that occur during ATP hydrolysis, we determined the X-ray crystallographic structures of the human TOP2B ATPase domain bound to AMPPNP or ADP at 1.9 Å and 2.6 Å resolution, respectively. The GHKL domains of both structures are similar, whereas the QTK loop within the transducer domain can move for product release. As TOP2B is the clinical target of bisdioxopiperazines, we also determined the structure of a TOP2B:ADP:ICRF193 complex to 2.3 Å resolution and identified key drug-binding residues. Biochemical characterization revealed the N-terminal strap reduces the rate of ATP hydrolysis. Mutagenesis demonstrated residue E103 as essential for ATP hydrolysis in TOP2B. Our data provide fundamental insights into the tertiary structure of the human TOP2B ATPase domain and a potential regulatory mechanism for ATP hydrolysis. Three structures of the TOP2B ATPase domain bound to AMPPNP, ADP, or ICRF193 The QTK loop in the ADP complex is further from the active site An SO4 ion is in place of the ATP hydrolysis product, Pi Biochemical data show the N-terminal strap reduces the ATPase hydrolysis activity
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Affiliation(s)
- Elise M Ling
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Arnaud Baslé
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Ian G Cowell
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Bert van den Berg
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Tim R Blower
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK.
| | - Caroline A Austin
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
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4
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Paulson JR, Hudson DF, Cisneros-Soberanis F, Earnshaw WC. Mitotic chromosomes. Semin Cell Dev Biol 2021; 117:7-29. [PMID: 33836947 PMCID: PMC8406421 DOI: 10.1016/j.semcdb.2021.03.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/23/2021] [Accepted: 03/23/2021] [Indexed: 01/25/2023]
Abstract
Our understanding of the structure and function of mitotic chromosomes has come a long way since these iconic objects were first recognized more than 140 years ago, though many details remain to be elucidated. In this chapter, we start with the early history of chromosome studies and then describe the path that led to our current understanding of the formation and structure of mitotic chromosomes. We also discuss some of the remaining questions. It is now well established that each mitotic chromatid consists of a central organizing region containing a so-called "chromosome scaffold" from which loops of DNA project radially. Only a few key non-histone proteins and protein complexes are required to form the chromosome: topoisomerase IIα, cohesin, condensin I and condensin II, and the chromokinesin KIF4A. These proteins are concentrated along the axis of the chromatid. Condensins I and II are primarily responsible for shaping the chromosome and the scaffold, and they produce the loops of DNA by an ATP-dependent process known as loop extrusion. Modelling of Hi-C data suggests that condensin II adopts a spiral staircase arrangement with an extruded loop extending out from each step in a roughly helical pattern. Condensin I then forms loops nested within these larger condensin II loops, thereby giving rise to the final compaction of the mitotic chromosome in a process that requires Topo IIα.
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Affiliation(s)
- James R Paulson
- Department of Chemistry, University of Wisconsin Oshkosh, 800 Algoma Boulevard, Oshkosh, WI 54901, USA.
| | - Damien F Hudson
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC 3052, Australia
| | - Fernanda Cisneros-Soberanis
- Wellcome Trust Centre for Cell Biology, ICB, University of Edinburgh, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, ICB, University of Edinburgh, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK.
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5
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Skok Ž, Zidar N, Kikelj D, Ilaš J. Dual Inhibitors of Human DNA Topoisomerase II and Other Cancer-Related Targets. J Med Chem 2019; 63:884-904. [DOI: 10.1021/acs.jmedchem.9b00726] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Žiga Skok
- Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Nace Zidar
- Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Danijel Kikelj
- Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Janez Ilaš
- Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
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6
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Austin CA, Lee KC, Swan RL, Khazeem MM, Manville CM, Cridland P, Treumann A, Porter A, Morris NJ, Cowell IG. TOP2B: The First Thirty Years. Int J Mol Sci 2018; 19:ijms19092765. [PMID: 30223465 PMCID: PMC6163646 DOI: 10.3390/ijms19092765] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 12/19/2022] Open
Abstract
Type II DNA topoisomerases (EC 5.99.1.3) are enzymes that catalyse topological changes in DNA in an ATP dependent manner. Strand passage reactions involve passing one double stranded DNA duplex (transported helix) through a transient enzyme-bridged break in another (gated helix). This activity is required for a range of cellular processes including transcription. Vertebrates have two isoforms: topoisomerase IIα and β. Topoisomerase IIβ was first reported in 1987. Here we review the research on DNA topoisomerase IIβ over the 30 years since its discovery.
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Affiliation(s)
- Caroline A Austin
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Ka C Lee
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Rebecca L Swan
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Mushtaq M Khazeem
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Catriona M Manville
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Peter Cridland
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Achim Treumann
- NUPPA, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Andrew Porter
- NUPPA, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Nick J Morris
- School of Biomedical Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
| | - Ian G Cowell
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
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7
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Development of pyridine dicoumarols as potent anti HIV-1 leads, targeting HIV-1 associated topoisomeraseIIβ kinase. Future Med Chem 2017; 9:1597-1609. [DOI: 10.4155/fmc-2017-0091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Aim: A structural study of a series of pyridine dicoumarol derivatives with potential activity against a novel Topoisomerase IIβ kinase which was identified in the HIV-1 viral lysate, compounds were designed and synthesized based on a 3D-QSAR study. Materials & methods: Based on QSAR model we have designed and synthesized a series of pyridine dicoumarol derivatives and characterized by spectral studies, all the molecules are biologically evaluated by kinase assay, cytotoxicity assay, ELISA and PCR method. Result: We demonstrated the achievement of water soluble disodium pyridine dicoumarate derivatives showing high anti-HIV-1 activity (IC50 <25 nM) which provides a crucial point for further development of pyridine dicoumarol series as HIV-1-associated topoisomerase IIβ kinase inhibitors for clinical application against AIDS. Conclusion: A new class of anti-HIV-1 lead compounds have been designed and tested. Further studies would result in development of novel and potential drugs.
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8
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Edgerton H, Johansson M, Keifenheim D, Mukherjee S, Chacón JM, Bachant J, Gardner MK, Clarke DJ. A noncatalytic function of the topoisomerase II CTD in Aurora B recruitment to inner centromeres during mitosis. J Cell Biol 2017; 213:651-64. [PMID: 27325791 PMCID: PMC4915189 DOI: 10.1083/jcb.201511080] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 05/25/2016] [Indexed: 11/22/2022] Open
Abstract
The C-terminal domain (CTD) of Topo II is dispensable for its catalytic activity yet essential for Topo II function in chromosome segregation during mitosis. Here, Edgerton et al. resolve the role of the Topo II CTD during mitosis in yeast, showing that it functions noncatalytically via the Haspin-H3 T3-Phos pathway to recruit Ipl1/Aurora B to mitotic inner centromeres. Faithful chromosome segregation depends on the precise timing of chromatid separation, which is enforced by checkpoint signals generated at kinetochores. Here, we provide evidence that the C-terminal domain (CTD) of DNA topoisomerase IIα (Topo II) provides a novel function at inner centromeres of kinetochores in mitosis. We find that the yeast CTD is required for recruitment of the tension checkpoint kinase Ipl1/Aurora B to inner centromeres in metaphase but is not required in interphase. Conserved CTD SUMOylation sites are required for Ipl1 recruitment. This inner-centromere CTD function is distinct from the catalytic activity of Topo II. Genetic and biochemical evidence suggests that Topo II recruits Ipl1 via the Haspin–histone H3 threonine 3 phosphorylation pathway. Finally, Topo II and Sgo1 are equally important for Ipl1 recruitment to inner centromeres. This indicates H3 T3-Phos/H2A T120-Phos is a universal epigenetic signature that defines the eukaryotic inner centromere and provides the binding site for Ipl1/Aurora B.
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Affiliation(s)
- Heather Edgerton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Marnie Johansson
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Daniel Keifenheim
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Soumya Mukherjee
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Jeremy M Chacón
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Jeff Bachant
- Department of Cell Biology and Neuroscience, University of California, Riverside, Riverside, CA 92521
| | - Melissa K Gardner
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
| | - Duncan J Clarke
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455
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9
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van Gijn R, Lendfers RRH, Schellens JHM, Bult A, Beijnen JH. Dual topoisomerase I/II inhibitors. J Oncol Pharm Pract 2016. [DOI: 10.1177/107815520000600303] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Topoisomerase (topo) I and II are nuclear enzymes, which play a major role in the topological rearrangement of DNA during replication and transcription processes. In the course of years, many different agents have been found which can inhibit the topos and thereby exploit cytotoxicity, also against tumour cells. Selective inhibition of the topo I enzyme can, however, induce a reactive increase in topo II levels, and vice versa. This mechanism is associated with the development of drug resistance. Dual inhibition of both topo I and II may, theoretically, overcome this resistance problem. In this review, the most important and promising dual topo I/II inhibitors designed as anticancer agents will be discussed. Thus far, only the indolyl quinoline derivative TAS-103, the 7 H-benzo [ e] pyrido [4,3- b] indole derivative intoplicine, and the acridine derivative PZA have been shown to be dual topo inhibitors with high cytotoxicity.
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Affiliation(s)
- R van Gijn
- Department of Pharmacy and Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - RRH Lendfers
- Department of Biomedical Analysis, Faculty of Pharmacy, Utrecht University, Utrecht, The Netherlands
| | - JHM Schellens
- Department of Biomedical Analysis, Faculty of Pharmacy, Utrecht University, Utrecht, The Netherlands, Division of Medical Oncology, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
| | - A Bult
- Department of Biomedical Analysis, Faculty of Pharmacy, Utrecht University, Utrecht, The Netherlands
| | - JH Beijnen
- Department of Pharmacy and Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute, Amsterdam, The Netherlands, Department of Biomedical Analysis, Faculty of Pharmacy, Utrecht University, Utrecht, The Netherlands
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10
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Manosalva P, Manohar M, Kogel KH, Kang HG, Klessig DF. The GHKL ATPase MORC1 Modulates Species-Specific Plant Immunity in Solanaceae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:927-42. [PMID: 25822715 DOI: 10.1094/mpmi-12-14-0401-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The microrchidia (MORC) proteins, a subset of the GHKL ATPase superfamily, were recently described as components involved in transcriptional gene silencing and plant immunity in Arabidopsis. To assess the role of MORC1 during resistance to Phytophthora infestans in solanaceous species, we altered the expression of the corresponding MORC1 homologs in potato, tomato, and Nicotiana benthamiana. Basal resistance to P. infestans was compromised in StMORC1-silenced potato and enhanced in overexpressing lines, indicating that StMORC1 positively affects immunity. By contrast, silencing SlMORC1 expression in tomato or NbMORC1 expression in N. benthamiana enhanced basal resistance to this oomycete pathogen. In addition, silencing SlMORC1 further enhanced resistance conferred by two resistance genes in tomato. Transient expression of StMORC1 in N. benthamiana accelerated cell death induced by infestin1 (INF1), whereas SlMORC1 or NbMORC1 suppressed it. Domain-swapping and mutational analyses indicated that the C-terminal region dictates the species-specific effects of the solanaceous MORC1 proteins on INF1-induced cell death. This C-terminal region also was required for homodimerization and phosphorylation of recombinant StMORC1 and SlMORC1, and its transient expression induced spontaneous cell death in N. benthamiana. Thus, this C-terminal region likely plays important roles in both determining and modulating the biological activity of MORC1 proteins.
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Affiliation(s)
- Patricia Manosalva
- 1 Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
- 2 Department of Plant Pathology and Microbiology, University of California Riverside, Riverside 92521, U.S.A
| | - Murli Manohar
- 1 Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
| | - Karl-Heinz Kogel
- 3 Research Centre for BioSystems, Land Use, and Nutrition, Justus Liebig University, Giessen D-35392, Germany; and
| | - Hong-Gu Kang
- 4 Department of Biology, Texas State University, San Marcos 78666, U.S.A
| | - Daniel F Klessig
- 1 Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A
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Targeting PKC delta-mediated topoisomerase II beta overexpression subverts the differentiation block in a retinoic acid-resistant APL cell line. Leukemia 2010; 24:729-39. [PMID: 20200558 DOI: 10.1038/leu.2010.27] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Retinoic acid (RA) relieves the maturation block in t(15:17) acute promyelocytic leukemia (APL), leading to granulocytic differentiation. However, RA treatment alone invariably results in RA resistance, both in vivo and in vitro. RA-resistant cell lines have been shown to serve as useful models for elucidation of mechanisms of resistance. Previously, we identified topoisomerase II beta (TOP2B) as a novel mediator of RA-resistance in APL cell lines. In this study, we show that both TOP2B protein stability and activity are regulated by a member of the protein kinase C (PRKC) family, PRKC delta (PRKCD). Co-treatment with a pharmacologic inhibitor of PRKCD and RA resulted in the induction of an RA responsive reporter construct, as well as the endogenous RA target genes, CEBPE, CYP26A1 and RIG-I. Furthermore, the co-treatment overcame the differentiation block in RA-resistant cells, as assessed by morphological analysis, restoration of promyelocytic leukemia nuclear bodies, induction of CD11c cell surface expression and an increase in nitro-blue-tetrazolium reduction. Cumulatively, our data suggest a model whereby inhibition of PRKCD decreases TOP2B protein levels, leading to a loss of TOP2B-mediated repressive effects on RA-induced transcription and granulocytic differentiation.
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12
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Abstract
DNA topoisomerases are enzymes that disentangle the topological problems that arise in double-stranded DNA. Many of these can be solved by the generation of either single or double strand breaks. However, where there is a clear requirement to alter DNA topology by introducing transient double strand breaks, only DNA topoisomerase II (TOP2) can carry out this reaction. Extensive biochemical and structural studies have provided detailed models of how TOP2 alters DNA structure, and recent molecular studies have greatly expanded knowledge of the biological contexts in which TOP2 functions, such as DNA replication, transcription and chromosome segregation -- processes that are essential for preventing tumorigenesis.
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Affiliation(s)
- John L Nitiss
- Molecular Pharmacology Department, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
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13
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Grozav AG, Chikamori K, Kozuki T, Grabowski DR, Bukowski RM, Willard B, Kinter M, Andersen AH, Ganapathi R, Ganapathi MK. Casein kinase I delta/epsilon phosphorylates topoisomerase IIalpha at serine-1106 and modulates DNA cleavage activity. Nucleic Acids Res 2008; 37:382-92. [PMID: 19043076 PMCID: PMC2632902 DOI: 10.1093/nar/gkn934] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously reported that phosphorylation of topoisomerase (topo) IIα at serine-1106 (Ser-1106) regulates enzyme activity and sensitivity to topo II-targeted drugs. In this study we demonstrate that phosphorylation of Ser-1106, which is flanked by acidic amino acids, is regulated in vivo by casein kinase (CK) Iδ and/or CKIɛ, but not by CKII. The CKI inhibitors, CKI-7 and IC261, reduced Ser-1106 phosphorylation and decreased formation of etoposide-stabilized topo II–DNA cleavable complex. In contrast, the CKII inhibitor, 5,6-dichlorobenzimidazole riboside, did not affect etoposide-stabilized topo II–DNA cleavable complex formation. Since, IC261 specifically targets the Ca2+-regulated isozymes, CKIδ and CKIɛ, we examined the effect of down-regulating these enzymes on Ser-1106 phosphorylation. Down-regulation of these isozymes with targeted si-RNAs led to hypophosphorylation of the Ser-1106 containing peptide. However, si-RNA-mediated down-regulation of CKIIα and α′ did not alter Ser-1106 phosphorylation. Furthermore, reduced phosphorylation of Ser-1106, observed in HRR25 (CKIδ/ɛ homologous gene)-deleted Saccharomyces cerevisiae cells transformed with human topo IIα, was enhanced following expression of human CKIɛ. Down-regulation of CKIδ and CKIɛ also led to reduced formation of etoposide stabilized topo II–DNA cleavable complex. These results provide strong support for an essential role of CKIδ/ɛ in phosphorylating Ser-1106 in human topo IIα and in regulating enzyme function.
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Affiliation(s)
- Adrian G Grozav
- Clinical Pharmacology Program, Taussig Cancer Institute, Cleveland, OH 44195, USA
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14
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Li H, Wang Y, Liu X. Plk1-dependent phosphorylation regulates functions of DNA topoisomerase IIalpha in cell cycle progression. J Biol Chem 2008; 283:6209-21. [PMID: 18171681 DOI: 10.1074/jbc.m709007200] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plk1 (Polo-like kinase 1) has been documented as a critical regulator of many mitotic events. However, increasing evidence supports the notion that Plk1 might also have functions outside of mitosis. Using biochemical fractionation and RNA interference approaches, we found that Plk1 was required for both G(1)/S and G(2)/M phases and that DNA topoisomerase IIalpha (topoIIalpha) was a potential target for Plk1 in both interphase and mitosis. Plk1 phosphorylates Ser(1337) and Ser(1524) of topoIIalpha. Overexpression of an unphosphorylatable topoIIalpha mutant led to S phase arrest, suggesting that Plk1-associated phosphorylation first occurs in S phase. Moreover, overexpression of the unphosphorylatable topoIIalpha mutant activated the ATM/R-dependent DNA damage checkpoint, probably due to reduced catalytic activity of topoIIalpha, and resulted in accumulation of catenated DNA. Finally, we showed that wild type topoIIalpha, but not the unphosphorylatable mutant, was able to rescue topoIIalpha depletion-induced defects in sister chromatid segregation, indicating that Plk1-associated phosphorylation is essential for the functions of topoIIalpha in mitosis.
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Affiliation(s)
- Hongchang Li
- Department of Biochemistry and the Cancer Center, Purdue University, 175 S. University Street, West Lafayette, IN 47907, USA
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15
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Chikamori K, Grabowski DR, Kinter M, Willard BB, Yadav S, Aebersold RH, Bukowski RM, Hickson ID, Andersen AH, Ganapathi R, Ganapathi MK. Phosphorylation of serine 1106 in the catalytic domain of topoisomerase II alpha regulates enzymatic activity and drug sensitivity. J Biol Chem 2003; 278:12696-702. [PMID: 12569090 DOI: 10.1074/jbc.m300837200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Topoisomerases alter DNA topology and are vital for the maintenance of genomic integrity. Topoisomerases I and II are also targets for widely used antitumor agents. We demonstrated previously that in the human leukemia cell line, HL-60, resistance to topoisomerase (topo) II-targeting drugs such as etoposide is associated with site-specific hypophosphorylation of topo II alpha. This effect can be mimicked in sensitive cells treated with the intracellular Ca(2+) chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM). Here we identify Ser-1106 as a major phosphorylation site in the catalytic domain of topo II alpha. This site lies within the consensus sequence for the acidotrophic kinases, casein kinase I and casein kinase II. Mutation of serine 1106 to alanine (S1106A) abrogates phosphorylation of phosphopeptides that were found to be hypophosphorylated in resistant HL-60 cells or sensitive cells treated with BAPTA-AM. Purified topo II alpha containing a S1106A substitution is 4-fold less active than wild type topo II alpha in decatenating kinetoplast DNA and also exhibits a 2-4-fold decrease in the level of etoposide-stabilized DNA cleavable complex formation. Saccharomyces cerevisiae (JN394t2-4) cells expressing S1106A mutant topo II alpha protein are more resistant to the cytotoxic effects of etoposide or amsacrine. These results demonstrate that Ca(2+)-regulated phosphorylation of Ser-1106 in the catalytic domain of topo II alpha modulates the enzymatic activity of this protein and sensitivity to topo II-targeting drugs.
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Affiliation(s)
- Kenichi Chikamori
- Experimental Therapeutics Program, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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16
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Palancade B, Dubois MF, Bensaude O. FCP1 phosphorylation by casein kinase 2 enhances binding to TFIIF and RNA polymerase II carboxyl-terminal domain phosphatase activity. J Biol Chem 2002; 277:36061-7. [PMID: 12138108 DOI: 10.1074/jbc.m205192200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dephosphorylation of RNA polymerase II carboxyl-terminal domain (CTD) is required to resume sequential transcription cycles. FCP1 (TFIIF-dependent CTD phosphatase 1) is the only known phosphatase targeting RNAP II CTD. Here we show that in Xenopus laevis cells, xFCP1 is a phosphoprotein. On the basis of biochemical fractionation and drug sensitivity, casein kinase 2 (CK2) is shown to be the major kinase involved in xFCP1 phosphorylation in X. laevis egg extracts. CK2 phosphorylates xFCP1 mainly at a cluster of serines centered on Ser(457). CK2-dependent phosphorylation enhances 4-fold the CTD phosphatase activity of FCP1 and its binding to the RAP74 subunit of general transcription factor TFIIF. These findings unravel a new mechanism regulating CTD phosphorylation and hence class II gene transcription.
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Affiliation(s)
- Benoît Palancade
- UMR 8541 CNRS, Génétique Moléculaire, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France
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17
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Ishida R, Takashima R, Koujin T, Shibata M, Nozaki N, Seto M, Mori H, Haraguchi T, Hiraoka Y. Mitotic specific phosphorylation of serine-1212 in human DNA topoisomerase IIalpha. Cell Struct Funct 2001; 26:215-26. [PMID: 11699638 DOI: 10.1247/csf.26.215] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
It is known that topoisomerase IIalpha is phosphorylated by several kinases. To elucidate the role of phosphorylation of topoisomerase IIalpha in the cell cycle, we have examined the cell cycle behavior of phosphorylated topoisomerase IIalpha in HeLa cells using antibodies against several phospho-oligopeptides of this enzyme. Here we demonstrate that serine1212 in topoisomerase IIalpha is phosphorylated only in the mitotic phase. Using an antibody against an oligopeptide containing phosphoserine-1212 in topoisomerase IIalpha (PS1212), subcellular localization of topoisomerase IIalpha phosphorylated at serine1212 was examined by indirect immunofluorescence staining, and compared with that of overall topoisomerase IIalpha. Serine1212-phosphorylated topoisomerase IIalpha was localized specifically on mitotic chromosomes, but not on interphase chromosomes; this result contrasts with overall topoisomerase IIalpha which was observed on chomosomes in both interphase and mitosis. Serine1212-phosphorylated topoisomerase lIalpha first appeared on chromosome arms in prophase, became concentrated on the centromeres in metaphase, and disappeared in early telophase. In addition, ICRF-193, a catalytic inhibitor of topoisomerase II, prevented accumulation of serine1212-phosphorylated topoisomerase IIalpha at the centromeres. These results indicate that serine1212 of topoisomerase IIalpha is phosphorylated specifically during mitosis, and suggest that the serine1212-phosphorylated topoisomerase IIalpha acts on resolving topological constraint progressively from the chromosome arm to the centromere during metaphase chromosome condensation.
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Affiliation(s)
- R Ishida
- Laboratory of Chemotherapy, Aichi Cancer Center Research Institute, Nagoya, Japan
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18
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Murnion ME, Adams RR, Callister DM, Allis CD, Earnshaw WC, Swedlow JR. Chromatin-associated protein phosphatase 1 regulates aurora-B and histone H3 phosphorylation. J Biol Chem 2001; 276:26656-65. [PMID: 11350965 DOI: 10.1074/jbc.m102288200] [Citation(s) in RCA: 202] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proper chromosome condensation requires the phosphorylation of histone and nonhistone chromatin proteins. We have used an in vitro chromosome assembly system based on Xenopus egg cytoplasmic extracts to study mitotic histone H3 phosphorylation. We identified a histone H3 Ser(10) kinase activity associated with isolated mitotic chromosomes. The histone H3 kinase was not affected by inhibitors of cyclin-dependent kinases, DNA-dependent protein kinase, p90(rsk), or cAMP-dependent protein kinase. The activity could be selectively eluted from mitotic chromosomes and immunoprecipitated by specific anti-X aurora-B/AIRK2 antibodies. This activity was regulated by phosphorylation. Treatment of X aurora-B immunoprecipitates with recombinant protein phosphatase 1 (PP1) inhibited kinase activity. The presence of PP1 on chromatin suggested that PP1 might directly regulate the X aurora-B associated kinase activity. Indeed, incubation of isolated interphase chromatin with the PP1-specific inhibitor I2 and ATP generated an H3 kinase activity that was also specifically immunoprecipitated by anti-X aurora-B antibodies. Nonetheless, we found that stimulation of histone H3 phosphorylation in interphase cytosol does not drive chromosome condensation or targeting of 13 S condensin to chromatin. In summary, the chromosome-associated mitotic histone H3 Ser(10) kinase is associated with X aurora-B and is inhibited directly in interphase chromatin by PP1.
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Affiliation(s)
- M E Murnion
- School of Life Sciences, Division of Molecular Cell Biology, University of Dundee, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, Scotland
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19
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Glover CV. On the physiological role of casein kinase II in Saccharomyces cerevisiae. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2001; 59:95-133. [PMID: 9427841 DOI: 10.1016/s0079-6603(08)61030-2] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Casein kinase II (CKII) is a highly conserved serine/threonine protein kinase that is ubiquitous in eukaryotic organisms. This review summarizes available data on CKII of the budding yeast Saccharomyces cerevisiae, with a view toward defining the possible physiological role of the enzyme. Saccharomyces cerevisiae CKII is composed of two catalytic and two regulatory subunits encoded by the CKA1, CKA2, CKB1, and CKB2 genes, respectively. Analysis of null and conditional alleles of these genes identifies a requirement for CKII in at least four biological processes: flocculation (which may reflect an effect on gene expression), cell cycle progression, cell polarity, and ion homeostasis. Consistent with this, isolation of multicopy suppressors of conditional cka mutations has identified three genes that have a known or potential role in either the cell cycle or cell polarity: CDC37, which is required for cell cycle progression in both G1 and G2/M; ZDS1 and 2, which appear to have a function in cell polarity; and SUN2, which encodes a protein of the regulatory component of the 26S protease. The identity and properties of known CKII substrates in S. cerevisiae are also reviewed, and advantage is taken of the complete genomic sequence to predict globally the substrates of CKII in this organism. Although the combined data do not yield a definitive picture of the physiological role of CKII, it is proposed that CKII serves a signal transduction function in sensing and/or communicating information about the ionic status of the cell to the cell cycle machinery.
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Affiliation(s)
- C V Glover
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens 30602, USA
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20
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Gemkow MJ, Dichter J, Arndt-Jovin DJ. Developmental regulation of DNA-topoisomerases during Drosophila embryogenesis. Exp Cell Res 2001; 262:114-21. [PMID: 11139335 DOI: 10.1006/excr.2000.5084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Type I and type II DNA-topoisomerases are essential enzymes that mediate replication, transcription, recombination, and mitosis in multicellular eukaryotes but the extent of their interchange for specific reactions in vivo is controversial. Expression patterns for topoisomerase I and topoisomerase II during the embryogenesis of Drosophila melanogaster were compared with patterns of DNA replication and expression of the histone genes. In late oogenesis the maternally supplied top2 mRNA was evenly distributed throughout the egg with elevated levels at the posterior tip, a pattern that is maintained in syncytial blastoderm embryos. During gastrulation, top2 mRNA became differentially localized only to regions of DNA replication, including new expression in the gonads preceding mitosis/meiosis. Significantly higher levels of top2 mRNA were found in mitotic compared to endoreplicating tissues. The total histone mRNA was exclusively associated with DNA replication but, in contrast to top2 mRNA, mitotic and endoreplicating cells contained similar expression levels with no expression in the gonads. Striking differences exist between the distribution of the top2 mRNA and topoisomerase II protein. The protein localizes to all evolving nuclei where it persists throughout embryogenesis. A high level of top1 mRNA transcript was present without differential tissue distribution throughout embryogenesis.
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Affiliation(s)
- M J Gemkow
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, 37070, Germany
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21
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Crevel G, Huikeshoven H, Cotterill S. Df31 is a novel nuclear protein involved in chromatin structure in Drosophila melanogaster. J Cell Sci 2001; 114:37-47. [PMID: 11112688 DOI: 10.1242/jcs.114.1.37] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We originally isolated the Df31 protein from Drosophila embryo extracts as a factor which could decondense Xenopus sperm, by removing the sperm specific proteins and interacting with histones to facilitate their loading onto DNA. We now believe that this protein has a more general function in cellular DNA metabolism. The Df31 gene encodes a very hydrophilic protein with a predicted molecular mass of 18.5 kDa. Immunostaining showed that Df31 was present in a wide range of cell types throughout differentiation and in both dividing and non-dividing cells. In all cases the protein is present in large amounts, comparable with the level of nucleosomes. Injection of antisense oligonucleotides to lower the level of Df31 in embryos caused severe disruption of the nuclear structure. Large irregular clumps of DNA were formed, and in most cases the amount of DNA associated with each clump was more than that found in a normal nucleus. Immunofluorescence, cell fractionation, and formaldehyde cross-linking show that Df31 is associated with chromatin and that a significant fraction of it binds very tightly. It also shows the same binding characteristics when loaded onto chromatin in vitro. Chromatin fractionation shows that Df31 is tightly associated with nucleosomes, preferentially with oligonucleosomes. Despite this no differences were observed in the properties of nucleosomes loaded in the in vitro system in the presence and absence of Df31. These results suggest that Df31 has a role in chromosomal structure, most likely acting as a structural protein at levels of folding higher than that of nucleosomes.
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Affiliation(s)
- G Crevel
- Dept Biochemistry and Immunology, St Georges Hospital Medical School, Cranmer Terrace, London SW17 ORE, UK
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22
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Abstract
Protein kinase CK2 is a ubiquitous and pleiotropic seryl/threonyl protein kinase which is highly conserved in evolution indicating a vital cellular role for this kinase. The holoenzyme is generally composed of two catalytic (alpha and/or alpha') and two regulatory (beta) subunits, but the free alpha/alpha' subunits are catalytically active by themselves and can be present in cells under some circumstances. Special attention has been devoted to phosphorylation status and structure of these enzymic molecules, however, their regulation and roles remain intriguing. Until recently, CK2 was believed to represent a kinase especially required for cell cycle progression in non-neural cells. At present, with respect to recent findings, four essential features suggest potentially important roles for this enzyme in specific neural functions: (1) CK2 is much more abundant in brain than in any other tissue; (2) there appear to be a myriad of substrates for CK2 in both synaptic and nuclear compartments that have clear implications in development, neuritogenesis, synaptic transmission, synaptic plasticity, information storage and survival; (3) CK2 seems to be associated with mechanisms underlying long-term potentiation in hippocampus; and (4) neurotrophins stimulate activity of CK2 in hippocampus. In addition, some data are suggestive that CK2 might play a role in processes underlying progressive disorders due to Alzheimer's disease, ischemia, chronic alcohol exposure or immunodeficiency virus HIV. The present review focuses mainly on the latest data concerning the regulatory mechanisms and the possible neurophysiological functions of this enzyme.
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Affiliation(s)
- P R Blanquet
- Unité de Recherche de Physiopharmacologie du Système Nerveux, U-161 INSERM, Paris, France.
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23
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Isaacs RJ, Davies SL, Sandri MI, Redwood C, Wells NJ, Hickson ID. Physiological regulation of eukaryotic topoisomerase II. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1400:121-37. [PMID: 9748535 DOI: 10.1016/s0167-4781(98)00131-6] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Topoisomerase II is an essential enzyme in all organisms with several independent roles in DNA metabolism. In this article we review our knowledge on the regulation of the expression and catalytic activity of topoisomerase II in both lower and higher eukaryotes. Current data indicate that the regulation of topoisomerase II gene expression is complex, with positive and negative controls in evidence at the level of both promoter activity and mRNA stability. Similarly, the activity of the mature enzyme can be regulated by the action of several different protein kinases. Of particular interest is the cell cycle-dependent phosphorylation of topoisomerase II, including multiple, mitosis-specific modifications, which are proposed to regulate the essential chromosome decatenation activity of the enzyme.
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Affiliation(s)
- R J Isaacs
- Imperial Cancer Research Fund Laboratories, Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK
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24
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Pinna LA, Meggio F. Protein kinase CK2 ("casein kinase-2") and its implication in cell division and proliferation. PROGRESS IN CELL CYCLE RESEARCH 1998; 3:77-97. [PMID: 9552408 DOI: 10.1007/978-1-4615-5371-7_7] [Citation(s) in RCA: 242] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Protein kinase CK2 (also termed casein kinase-2 or -II) is a ubiquitous Ser/Thr-specific protein kinase required for viability and for cell cycle progression. CK2 is especially elevated in proliferating tissues, either normal or transformed, and the expression of its catalytic subunit in transgenic mice is causative of lymphomas. CK2 is highly pleiotropic: more than 160 proteins phosphorylated by it at sites specified by multiple acidic residues are known. Despite its heterotetrameric structure generally composed by two catalytic (alpha and/or alpha') and two non catalytic beta-subunits, the regulation of CK2 is still enigmatic. A number of functional features of the beta-subunit which could cooperate to the modulation of CK2 targeting/activity will be discussed.
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Affiliation(s)
- L A Pinna
- Dipartimento di Chimica Biologica, Università di Padova, Italy
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25
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Abstract
Type II DNA topoisomerase activity is required to change DNA topology. It is important in the relaxation of DNA supercoils generated by cellular processes, such as transcription and replication, and it is essential for the condensation of chromosomes and their segregation during mitosis. In mammals this activity is derived from at least two isoforms, termed DNA topoisomerase II alpha and beta. The alpha isoform is involved in chromosome condensation and segregation, whereas the role of the beta isoform is not yet clear. DNA topoisomerase II beta was first reported in 1987. Here we review the research on DNA topoisomerase II beta over the last 10 years.
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Affiliation(s)
- C A Austin
- Department of Biochemistry and Genetics, Medical School, University of Newcastle, Newcastle-upon-Tyne, United Kingdom.
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26
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Hammonds TR, Maxwell A. The DNA dependence of the ATPase activity of human DNA topoisomerase IIalpha. J Biol Chem 1997; 272:32696-703. [PMID: 9405488 DOI: 10.1074/jbc.272.51.32696] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We have purified human topoisomerase IIalpha from HeLa cells and studied its ATPase reaction. The ATPase activity is stimulated by DNA and shows apparent Michaelis-Menten kinetics. Although the ATPase activity of human topoisomerase IIalpha is lower than that of Saccharomyces cerevisiae, it is more active in decatenation, implying more efficient coupling of the ATPase to DNA strand passage under these conditions. Using plasmid pBR322 as the DNA cofactor, the reaction shows hyperstimulation by DNA at a base pair to enzyme dimer ratio of 100-200:1. When DNA fragments are used as the cofactor, the reaction requires > approximately 100 base pairs to stimulate the activity and fragments of approximately 300 base pairs show hyperstimulation. This behavior can be rationalized in terms of the enzyme requiring fragments that can bind to both the DNA gate and the ATP-operated clamp in order for the ATPase reaction to be stimulated. Hyperstimulation is a consequence of the saturation of DNA with enzyme. The mechanistic implications of these results are discussed.
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Affiliation(s)
- T R Hammonds
- Department of Biochemistry, University of Leicester, Leicester LE1 7RH, United Kingdom
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27
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Komori K, Kuroe K, Yanagisawa K, Tanaka Y. Cloning and characterization of the gene encoding a mitochondrially localized DNA topoisomerase II in Dictyostelium discoideum. Western blot analysis. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1352:63-72. [PMID: 9177484 DOI: 10.1016/s0167-4781(96)00229-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We cloned a gene (topA) encoding DNA topoisomerase II from Dictyostelium discoideum nuclear DNA using oligo probes corresponding to the consensus amino acid sequences found in the gene in other eukaryotes. The gene encoding a predicted polypeptide of 1282 amino acids with M(r) of about 146 kDa, is a single copy that is expressed as a polyadenylated 4.5 kb RNA. The predicted amino acid sequence shares similarity with those of other eukaryotes with identity between 32 and 46%. The protein is 260-300 amino acids shorter in the C-terminal region and 50-80 longer in the N-terminal region than those of other eukaryotes. In TopA of D. discoideum, the N-terminal region with stretches of charged and hydrophilic amino acids is predicted to fold into an amphiphilic alpha-helix which is characteristic of a mitochondrial targeting signal presequence. Four independent polyclonal antibodies against bacterially expressed GST fusion proteins containing four portions of the polypeptide detected a single band on Western blots at about 135 kDa. Western blots analysis of subcellular fractions revealed that this protein is localized in mitochondria. The protein and the mRNA are present in growth phase and during development, although levels of both declined as development proceeded.
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Affiliation(s)
- K Komori
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan
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28
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Meyer KN, Kjeldsen E, Straub T, Knudsen BR, Hickson ID, Kikuchi A, Kreipe H, Boege F. Cell cycle-coupled relocation of types I and II topoisomerases and modulation of catalytic enzyme activities. J Biophys Biochem Cytol 1997; 136:775-88. [PMID: 9049244 PMCID: PMC2132491 DOI: 10.1083/jcb.136.4.775] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We visualized DNA topoisomerases in A431 cells and isolated chromosomes by isoenzyme-selective immunofluorescence microscopy. In interphase, topoisomerase I mainly had a homogeneous nuclear distribution. 10-15% of the cells exhibited granular patterns, 30% showed bright intranucleolar patches. Topoisomerase II isoenzymes showed spotted (alpha) or reticular (beta) nuclear patterns throughout interphase. In contrast to topoisomerase IIalpha, topoisomerase IIbeta was completely excluded from nucleoli. In mitosis, topoisomerase IIbeta diffused completely into the cytosol, whereas topoisomerases I and IIalpha remained chromosome bound. Chromosomal staining of topoisomerase I was homogeneous, whereas topoisomerase IIalpha accumulated in the long axes of the chromosome arms and in the centriols. Topoisomerase antigens were 2-3-fold higher in mitosis than in interphase, but specific activities of topoisomerase I and II were reduced 5- and 2.4-fold, respectively. These changes were associated with mitotic enzyme hyperphosphorylation. In interphase, topoisomerases could be completely linked to DNA by etoposide or camptothecin, whereas in mitosis, 50% of topoisomerase IIalpha escaped poisoning. Refractoriness to etoposide could be assigned to the salt-stable scaffold fraction of topoisomerase IIalpha, which increased from <2% in G1 phase to 48% in mitosis. Topoisomerases I and IIbeta remained completely extractable throughout the cell cycle. In summary, expression of topoisomerases increases towards mitosis, but specific activities decrease. Topoisomerase IIbeta is released from the heterochromatin, whereas topoisomerase I and IIalpha remain chromosome bound. Scaffold-associated topoisomerase IIalpha appears not to be involved in catalytic DNA turnover, though it may play a role in the replicational cycle of centriols, where it accumulates during M phase.
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Affiliation(s)
- K N Meyer
- Medizinische Poliklinik, University of Wurzburg, Germany
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29
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Ishida R, Iwai M, Marsh KL, Austin CA, Yano T, Shibata M, Nozaki N, Hara A. Threonine 1342 in human topoisomerase IIalpha is phosphorylated throughout the cell cycle. J Biol Chem 1996; 271:30077-82. [PMID: 8939955 DOI: 10.1074/jbc.271.47.30077] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
To investigate the relationship between the modulation of topoisomerase II activity and its phosphorylation state during the cell cycle, a monoclonal antibody against C-terminal peptide (residues 1335-1350) of topoisomerase IIalpha containing a consensus sequence of casein kinase II, TDDE and its phosphorylated threonine were prepared. In an enzyme-linked immunosorbent assay, the antibody, named PT1342, recognized the immunogenic phosphopeptide but not the non-phosphorylated form of the peptide. The PT1342 antibody reacted only with a 170-kDa protein from HeLa cells and recognized anti-topoisomerase IIalpha immunoprecipitants. Furthermore, the antibody did not react with the human topoisomerase IIalpha mutated at codon 1342 from threonine to alanine, showing that PT1342 was directed against the phosphorylated threonine 1342. To examine the level of phosphorylation of threonine 1342 of topoisomerase IIalpha through the cell cycle, HeLa cells were stained simultaneously for phosphorylated topoisomerase IIalpha and DNA and analyzed by flow cytometry. Cells in the G2-M phase contained about double the PT1341-reacted topoisomerase IIalpha than did cells in G1 or S phases. The antibody stained the nuclei in interphase and mitotic chromosomes and its periphery, as seen with anti-topoisomerase IIalpha antibody. Thus, threonine 1342 in topoisomerase IIalpha is phosphorylated throughout the cell cycle.
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Affiliation(s)
- R Ishida
- Laboratory of Biochemistry, Aichi Cancer Center Research Institute, Chikusa-Ku, Nagoya 464, Japan
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30
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Kimura K, Nozaki N, Enomoto T, Tanaka M, Kikuchi A. Analysis of M phase-specific phosphorylation of DNA topoisomerase II. J Biol Chem 1996; 271:21439-45. [PMID: 8702926 DOI: 10.1074/jbc.271.35.21439] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In mammalian cells, two isoforms of DNA topoisomerase II (topo II), topo IIalpha and topo IIbeta, are phosphorylated. The phosphorylation of topo IIbeta changes its apparent molecular mass determined by SDS-polyacrylamide gel electrophoresis from 180 to 190 kDa in mitotic cells, whereas topo IIalpha affects it only slightly (Kimura, K., Nozaki, N., Saijo, M., Kikuchi, A., Ui, M., and Enomoto, T. (1994) J. Biol. Chem. 269, 24523-24526). Here we examined the stability of the protein and the phosphate moiety of each topo II isoform, as the cells progressed from M to G1 phase. While its protein moiety remained intact, 75% of the phosphates attached to topo IIbeta were removed within 4 h after release from mitotic block. On the other hand, 35% of topo IIalpha protein and 52% of the attached phosphates disappeared. We verified that M phase-specific phosphorylation had no particular effect on the catalytic activities of both topo II isoforms after extensive phosphatase digestion. We also examined the binding of two isoforms to the nucleus or chromosomes. In logarithmically growing cells, both isoforms were extracted from nuclei at the same concentrations of NaCl. From the mitotic chromosomes, topo IIbeta was extracted at much lower concentrations of NaCl than topo IIalpha.
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Affiliation(s)
- K Kimura
- Mitsubishi Kasei Institute of Life Sciences, Machida, Tokyo 194
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31
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Affiliation(s)
- S Joel
- ICRF Department of Medical Oncology, St Bartholomew's Hospital, London, U.K
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Faust RA, Gapany M, Tristani P, Davis A, Adams GL, Ahmed K. Elevated protein kinase CK2 activity in chromatin of head and neck tumors: association with malignant transformation. Cancer Lett 1996; 101:31-5. [PMID: 8625279 DOI: 10.1016/0304-3835(96)04110-9] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We hypothesized that malignant transformation of normal mucosa of the upper aerodigestive tract to squamous cell carcinoma of the head and neck (SCCHN) might be associated with altered CK2 activity in the chromatin compartment of these tumors. We measured CK2 activity in the cytosol and chromatin of 7 surgical specimens of SCCHN, and 5 specimens of normal oropharyngeal mucosa from non-smokers/non-drinkers. CK2 activity in SCCHN tumors was significantly elevated in both the nuclear chromatin (P < 0.0005) and cytosolic (P <0.04) compartments relative to normal mucosa. These data suggest that activation of dysregulation of the chromatin-associated CK2 signal may play a role in the pathobiology od SCCHN.
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Affiliation(s)
- R A Faust
- Department of Otolaryngology, Head and Neck Surgery, University of Minnesota, Minneapolis, 55417, USA
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Wells NJ, Fry AM, Guano F, Norbury C, Hickson ID. Cell cycle phase-specific phosphorylation of human topoisomerase II alpha. Evidence of a role for protein kinase C. J Biol Chem 1995; 270:28357-63. [PMID: 7499337 DOI: 10.1074/jbc.270.47.28357] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Type II topoisomerases are essential for faithful cell division in all organisms. In human cells, the alpha isozyme of topoisomerase II has been implicated in catalyzing mitotic chromosome segregation via its action as a DNA unlinking enzyme. Here, we have shown that the enzymatic activity of topoisomerase II alpha protein purified from HeLa cell nuclei was strongly enhanced following phosphorylation by protein kinase C. We have investigated the possibility that this kinase is involved in cell cycle phase-specific phosphorylation of topoisomerase II alpha in HeLa cells. Two-dimensional tryptic phosphopeptide mapping revealed that topoisomerase II alpha protein immunoprecipitated from metabolically labeled HeLa cells was differentially phosphorylated during the G2/M phases of the cell cycle. To identify sites of phosphorylation, and the kinase(s) responsible for this modification, oligohistidine-tagged recombinant domains of topoisomerase II alpha protein were overexpressed in Escherichia coli and purified by affinity chromatography. Phosphorylation of a short fragment of the N-terminal ATPase domain of topoisomerase II alpha by protein kinase C in vitro generated two phosphopeptides that co-migrated with prominent G2/M phase-specific phosphopeptides from the HeLa cell-derived topoisomerase II alpha protein. Site-directed mutagenesis studies indicated that phosphorylation of serine 29 generated both of these phosphopeptides. Our results implicate protein kinase C in the cell cycle phase-dependent modulation of topoisomerase II alpha enzymatic activity in human cells.
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Affiliation(s)
- N J Wells
- Imperial Cancer Research Fund Laboratories, Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, United Kingdom
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Hanna DE, Rethinaswamy A, Glover CV. Casein kinase II is required for cell cycle progression during G1 and G2/M in Saccharomyces cerevisiae. J Biol Chem 1995; 270:25905-14. [PMID: 7592778 DOI: 10.1074/jbc.270.43.25905] [Citation(s) in RCA: 159] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The catalytic subunit of Saccharomyces cerevisiae casein kinase II (Sc CKII) is encoded by the CKA1 and CKA2 genes, which together are essential for viability. Five independent temperature-sensitive alleles of the CKA2 gene were isolated and used to analyze the function of CKII during the cell cycle. Following a shift to the nonpermissive temperature, cka2ts strains arrested within a single cell cycle and exhibited a dual arrest phenotype consisting of 50% unbudded and 50% large-budded cells. The unbudded half of the arrested population contained a single nucleus and a single focus of microtubule staining, consistent with arrest in G1. Most of the large-budded fraction contained segregated chromatin and an extended spindle, indicative of arrest in anaphase, though a fraction contained an undivided nucleus with a short thick intranuclear spindle, indicative of arrest in G2 and/or metaphase. Flow cytometry of pheromone-synchronized cells confirmed that CKII is required in G1, at a point which must lie at or beyond Start but prior to DNA synthesis. Similar analysis of hydroxyurea-synchronized cells indicated that CKII is not required for completion of previously initiated DNA replication but confirmed that the enzyme is again required for cell cycle progression in G2 and/or mitosis. These results establish a role for CKII in regulation and/or execution of the eukaryotic cell cycle.
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Affiliation(s)
- D E Hanna
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens 30602-7229, USA
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Vassetzky YS, Alghisi GC, Gasser SM. DNA topoisomerase II mutations and resistance to anti-tumor drugs. Bioessays 1995; 17:767-74. [PMID: 8763829 DOI: 10.1002/bies.950170906] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mutations in DNA topoisomerase II are often correlated with drug-resistance in tumor cell lines. Studies of topoisomerase II-mediated drug-resistance in various model systems, as well as the sequencing of such mutations from drug-resistant tumors, have shed light on the functional domains of topoisomerase II, on how it interacts with inhibitors, and on the different mechanisms by which cells avoid the toxic effects of many clinically important anti-tumor drugs.
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Affiliation(s)
- Y S Vassetzky
- Swiss Institute for Experimental Cancer Research (ISREC), Epalinges/Lausanne, Switzerland
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Upton T, Wiltshire S, Francesconi S, Eisenberg S. ABF1 Ser-720 is a predominant phosphorylation site for casein kinase II of Saccharomyces cerevisiae. J Biol Chem 1995; 270:16153-9. [PMID: 7608180 DOI: 10.1074/jbc.270.27.16153] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
ABF1 is a multifunctional phosphoprotein that binds specifically to yeast origins of replication and to transcriptional regulatory sites of a variety of genes. We isolated a protein kinase from extracts of Saccharomyces cerevisiae on the basis of its ability to specifically phosphorylate the ABF1 protein. Physical and biochemical properties of this kinase identify it as casein kinase II (CKII). The purified kinase has a high affinity for the ABF1 substrate as indicated by a relatively low Km value. Furthermore, when incubated with ABF1 and anti-ABF1 antibodies, the kinase forms an immunocomplex active in the phosphorylation of ABF1. Biochemical and genetic mapping localized a major site for phosphorylation at Ser-720 near the C terminus of the ABF1 protein. This serine is embedded within a domain enriched for acidic amino acid residues. A Ser-720 to Ala mutation abolishes phosphorylation by CKII in vitro. The same mutation also abolishes phosphorylation of this site in vivo, suggesting that CKII phosphorylates Ser-720 in vivo as well. Although three CKII enzymes, yeast, sea star, and recombinant human, utilize casein as a substrate with similar efficiencies, only the yeast enzyme efficiently phosphorylates the ABF1 protein. This suggests that ABF1 is a specific substrate of the yeast CKII and that this specificity may reside within one of the beta regulatory subunits of the enzyme. Thus, phosphorylation of ABF1 by yeast CKII may prove to be a useful system for studying targeting mechanisms of CKII to a physiological substrate.
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Affiliation(s)
- T Upton
- Department of Microbiology, University of Connecticut Medical School, Farmington 06030, USA
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Baloch Z, Cohen S, Fresa K, Coffman FD. Modulation of topoisomerase activities by tumor necrosis factor. Cell Immunol 1995; 160:98-103. [PMID: 7842491 DOI: 10.1016/0008-8749(95)80014-a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A number of chemotherapeutic agents which inhibit the DNA topoisomerases markedly potentiate cell death mediated by tumor necrosis factor, suggesting a role for these enzymes in the TNF cytotoxic mechanism. To investigate this possibility, topoisomerase I and II activities were assayed following TNF addition to murine L929 cells. Topoisomerase I and II activities increased within 15 min of TNF addition and returned to baseline levels within 1 and 2 hr, respectively. The increases in both topoisomerase activities were blocked by H-7 (but not H-8) and similar increases were seen following PMA addition. However, concentrations of H-7 which blocked the increased topoisomerase activities had no effect on TNF cytotoxicity nor on the enhancement of TNF cytotoxicity by topoisomerase inhibitors. Thus, in these cells topoisomerase activities are directly modified by TNF during the initial phases of a cytotoxic response. However, neither TNF cytotoxicity nor the enhancement of TNF cytotoxicity by topoisomerase inhibitors appears to require the TNF-mediated increases in topoisomerase activities.
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Affiliation(s)
- Z Baloch
- Department of Pathology, UMDNJ, Newark 07103
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38
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Association of casein kinase 2 with nuclear matrix. Possible role in nuclear matrix protein phosphorylation. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37312-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Skovsgaard T, Nielsen D, Maare C, Wassermann K. Cellular resistance to cancer chemotherapy. INTERNATIONAL REVIEW OF CYTOLOGY 1994; 156:77-157. [PMID: 7860220 DOI: 10.1016/s0074-7696(08)62253-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- T Skovsgaard
- Department of Oncology, University of Copenhagen, Herlev Hospital, Denmark
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Evans CD, Mirski SE, Danks MK, Cole SP. Reduced levels of topoisomerase II alpha and II beta in a multidrug-resistant lung-cancer cell line. Cancer Chemother Pharmacol 1994; 34:242-8. [PMID: 8004758 DOI: 10.1007/bf00685084] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have previously shown that the doxorubicin-selected multidrug-resistant small-cell lung-cancer cell line H69AR is resistant to VP-16-induced single-strand DNA breaks as compared with its parental H69 cell line. Levels of immunoreactive topoisomerase II alpha are also reduced in H69AR cells. In the present study, we found that cleaved complex formation in the presence of VP-16 was decreased in H69AR cells as compared with H69 cells. In addition, the resistant cells contained lower levels of both topoisomerase II alpha and topoisomerase II beta protein and mRNA. However, these changes were not accompanied by a decrease in the P4-unknotting (strand-passing) activity of 0.67 M NaCl nuclear extracts of H69AR cells, nor was there any difference in VP-16 inhibition of unknotting activity in the H69 and H69AR nuclear extracts. These data suggest that reduced levels of topoisomerase II alpha and II beta may contribute to the resistance of H69AR cells to VP-16 and other drugs that target these isoenzymes.
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Affiliation(s)
- C D Evans
- Department of Pharmacology and Toxicology, Queen's University, Kingston, Ontario, Canada
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41
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Bolander FF. Hormonally Regulated Transcription Factors. Mol Endocrinol 1994. [DOI: 10.1016/b978-0-12-111231-8.50017-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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42
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Cardenas ME, Walter R, Hanna D, Gasser SM. Casein kinase II copurifies with yeast DNA topoisomerase II and re-activates the dephosphorylated enzyme. J Cell Sci 1993; 104 ( Pt 2):533-43. [PMID: 8389377 DOI: 10.1242/jcs.104.2.533] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mitotic division in yeast requires the activity of topoisomerase II, a DNA topology modifying enzyme that is able to disentangle sister chromatids after DNA replication. Previous work has shown that topoisomerase II is a phosphoprotein in intact yeast cells. We show here that when dephosphorylated in vitro, topoisomerase II is unable to cleave or decatenate kinetoplast DNA. An efficient kinase activity that modifies topoisomerase II on seven major sites was found to copurify with the enzyme purified from yeast. Characterization of this kinase, analysis of phosphotryptic peptides, and studies with a yeast mutant deficient in casein kinase II, indicate that the copurifying kinase is casein kinase II (CKII). Topoisomerase II itself has no self-phosphorylating activity. Modification of topoisomerase II by the copurifying kinase is sufficient to restore decatenation activity after dephosphorylation by alkaline phosphatase. The CKII target sites have been mapped to multiple serine and threonine residues on 4 tryptic fragments within the C-terminal 350 amino acids of yeast topoisomerase II. These results are consistent with a model in which the C-terminal domain of topoisomerase II is a negative regulatory domain that is neutralized by phosphorylation.
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Affiliation(s)
- M E Cardenas
- Swiss Institute for Experimental Cancer Research, Epalinges s/Lausanne
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