1
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Kono Y, Shimi T. Crosstalk between mitotic reassembly and repair of the nuclear envelope. Nucleus 2024; 15:2352203. [PMID: 38780365 PMCID: PMC11123513 DOI: 10.1080/19491034.2024.2352203] [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: 09/01/2023] [Accepted: 05/01/2024] [Indexed: 05/25/2024] Open
Abstract
In eukaryotic cells, the nuclear envelope (NE) is a membrane partition between the nucleus and the cytoplasm to compartmentalize nuclear contents. It plays an important role in facilitating nuclear functions including transcription, DNA replication and repair. In mammalian cells, the NE breaks down and then reforms during cell division, and in interphase it is restored shortly after the NE rupture induced by mechanical force. In this way, the partitioning effect is regulated through dynamic processes throughout the cell cycle. A failure in rebuilding the NE structure triggers the mixing of nuclear and cytoplasmic contents, leading to catastrophic consequences for the nuclear functions. Whereas the precise details of molecular mechanisms for NE reformation during cell division and NE restoration in interphase are still being investigated, here, we mostly focus on mammalian cells to describe key aspects that have been identified and to discuss the crosstalk between them.
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Affiliation(s)
- Yohei Kono
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Takeshi Shimi
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan
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2
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Xu Y, Chao A, Rinaldin M, Kickuth A, Brugués J, Di Talia S. The cell cycle oscillator and spindle length set the speed of chromosome separation in Drosophila embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.17.598879. [PMID: 38948726 PMCID: PMC11212860 DOI: 10.1101/2024.06.17.598879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Anaphase is tightly controlled in space and time to ensure proper separation of chromosomes. The mitotic spindle, the self-organized microtubule structure driving chromosome segregation, scales in size with the available cytoplasm. Yet, the relationship between spindle size and chromosome movement remains poorly understood. Here, we address how the movement of chromosomes changes during the cleavage divisions of the Drosophila blastoderm. We show that the speed of chromosome separation gradually decreases during the 4 nuclear divisions of the blastoderm. This reduction in speed is accompanied by a similar reduction in the length of the spindle, thus ensuring that these two quantities are tightly linked. Using a combination of genetic and quantitative imaging approaches, we find that two processes contribute to controlling the speed at which chromosomes move at mitotic exit: the activity of molecular motors important for microtubule depolymerization and the cell cycle oscillator. Specifically, we found that the levels of Klp10A, Klp67A, and Klp59C, three kinesin-like proteins important for microtubule depolymerization, contribute to setting the speed of chromosome separation. This observation is supported by quantification of microtubule dynamics indicating that poleward flux rate scales with the length of the spindle. Perturbations of the cell cycle oscillator using heterozygous mutants of mitotic kinases and phosphatases revealed that the duration of anaphase increases during the blastoderm cycles and is the major regulator of chromosome velocity. Thus, our work suggests a potential link between the biochemical rate of mitotic exit and the forces exerted by the spindle. Collectively, we propose that the cell cycle oscillator and spindle length set the speed of chromosome separation in anaphase.
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Affiliation(s)
- Yitong Xu
- Department of Cell Biology, Duke University Medical Center, Durham NC 27705, USA
| | - Anna Chao
- Department of Cell Biology, Duke University Medical Center, Durham NC 27705, USA
| | - Melissa Rinaldin
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, 01307 Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
- Center of Systems Biology, Dresden, 01307 Germany
| | - Alison Kickuth
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, 01307 Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
- Center of Systems Biology, Dresden, 01307 Germany
| | - Jan Brugués
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, 01307 Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
- Center of Systems Biology, Dresden, 01307 Germany
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham NC 27705, USA
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3
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Kapoor S, Adhikary K, Kotak S. PP2A-B55 SUR-6 promotes nuclear envelope breakdown in C. elegans embryos. Cell Rep 2023; 42:113495. [PMID: 37995185 DOI: 10.1016/j.celrep.2023.113495] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/25/2023] [Accepted: 11/09/2023] [Indexed: 11/25/2023] Open
Abstract
Nuclear envelope (NE) disassembly during mitosis is critical to ensure faithful segregation of the genetic material. NE disassembly is a phosphorylation-dependent process wherein mitotic kinases hyper-phosphorylate lamina and nucleoporins to initiate nuclear envelope breakdown (NEBD). In this study, we uncover an unexpected role of the PP2A phosphatase B55SUR-6 in NEBD during the first embryonic division of Caenorhabditis elegans embryo. B55SUR-6 depletion delays NE permeabilization and stabilizes lamina and nucleoporins. As a result, the merging of parental genomes and chromosome segregation is impaired. NEBD defect upon B55SUR-6 depletion is not due to delayed mitotic onset or mislocalization of mitotic kinases. Importantly, we demonstrate that microtubule-dependent mechanical forces synergize with B55SUR-6 for efficient NEBD. Finally, our data suggest that the lamin LMN-1 is likely a bona fide target of PP2A-B55SUR-6. These findings establish a model highlighting biochemical crosstalk between kinases, PP2A-B55SUR-6 phosphatase, and microtubule-generated mechanical forces in timely NE dissolution.
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Affiliation(s)
- Sukriti Kapoor
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore 560012, India
| | - Kuheli Adhikary
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore 560012, India
| | - Sachin Kotak
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore 560012, India.
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4
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Halfmann CT, Scott KL, Sears RM, Roux KJ. Mechanisms by which barrier-to-autointegration factor regulates dynamics of nucleocytoplasmic leakage and membrane repair following nuclear envelope rupture. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.21.572811. [PMID: 38187776 PMCID: PMC10769424 DOI: 10.1101/2023.12.21.572811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The nuclear envelope (NE) creates a barrier between the cytosol and nucleus during interphase that is key for cellular compartmentalization and protecting genomic DNA. NE rupture can expose genomic DNA to the cytosol and allow admixture of the nuclear and cytosolic constituents, a proposed mechanism of cancer and NE-associated diseases. Barrier-to-autointegration factor (BAF) is a DNA-binding protein that localizes to NE ruptures where it recruits LEM-domain proteins, A-type lamins, and participates in rupture repair. To further reveal the mechanisms by which BAF responds to and aids in repairing NE ruptures, we investigated known properties of BAF including LEM domain binding, lamin binding, compartmentalization, phosphoregulation of DNA binding, and BAF dimerization. We demonstrate that it is the cytosolic population of BAF that functionally repairs NE ruptures, and phosphoregulation of BAF's DNA-binding that enables its ability to facilitate that repair. Interestingly, BAF's LEM or lamin binding activity appears dispensable for its role in functional repair. Furthermore, we demonstrate that BAF functions to reduce the extent of leakage though NE ruptures, suggesting that BAF effectively forms a diffusion barrier prior to NE repair. Collectively, these results enhances our knowledge of the mechanisms by which BAF responds to NE ruptures and facilitates their repair.
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Affiliation(s)
| | - Kelsey L. Scott
- Enabling Technologies Group, Sanford Research, Sioux Falls SD
| | - Rhiannon M. Sears
- Enabling Technologies Group, Sanford Research, Sioux Falls SD
- Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD
| | - Kyle J. Roux
- Enabling Technologies Group, Sanford Research, Sioux Falls SD
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls SD
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5
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Emond-Fraser V, Larouche M, Kubiniok P, Bonneil É, Li J, Bourouh M, Frizzi L, Thibault P, Archambault V. Identification of PP2A-B55 targets uncovers regulation of emerin during nuclear envelope reassembly in Drosophila. Open Biol 2023; 13:230104. [PMID: 37463656 PMCID: PMC10353892 DOI: 10.1098/rsob.230104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/21/2023] [Indexed: 07/20/2023] Open
Abstract
Mitotic exit requires the dephosphorylation of many proteins whose phosphorylation was needed for mitosis. Protein phosphatase 2A with its B55 regulatory subunit (PP2A-B55) promotes this transition. However, the events and substrates that it regulates are incompletely understood. We used proteomic approaches in Drosophila to identify proteins that interact with and are dephosphorylated by PP2A-B55. Among several candidates, we identified emerin (otefin in Drosophila). Emerin resides in the inner nuclear membrane and interacts with the DNA-binding protein barrier-to-autointegration factor (BAF) via a LEM domain. We found that the phosphorylation of emerin at Ser50 and Ser54 near its LEM domain negatively regulates its association with BAF, lamin and additional emerin in mitosis. We show that dephosphorylation of emerin at these sites by PP2A-B55 determines the timing of nuclear envelope reformation. Genetic experiments indicate that this regulation is required during embryonic development. Phosphoregulation of the emerin-BAF complex formation by PP2A-B55 appears as a key event of mitotic exit that is likely conserved across species.
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Affiliation(s)
- Virginie Emond-Fraser
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Myreille Larouche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Peter Kubiniok
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Éric Bonneil
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Jingjing Li
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Mohammed Bourouh
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Laura Frizzi
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Pierre Thibault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de chimie, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
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6
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Li M, Li S, Zhang L. Phosphorylation Promotes the Accumulation of PERIOD Protein Foci. RESEARCH (WASHINGTON, D.C.) 2023; 6:0139. [PMID: 37223461 PMCID: PMC10202380 DOI: 10.34133/research.0139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/17/2023] [Indexed: 05/25/2023]
Abstract
Circadian clock drives the 24-h rhythm in our behavior and physiology. The molecular clock consists of a series of transcriptional/translational feedback loops operated by a number of clock genes. A very recent study reported that the clock protein PERIOD (PER) is organized into discrete foci at the nuclear envelope in fly circadian neurons, which is believed to be important for controlling the subcellular localization of clock genes. Loss of inner nuclear membrane protein lamin B receptor (LBR) leads to disruption of these foci, but how they are regulated is yet unknown. Here, we found that PER foci are likely phase-separated condensates, the formation of which is mediated by intrinsically disordered region in PER. Phosphorylation promotes the accumulation of these foci. Protein phosphatase 2A, which is known to dephosphorylate PER, hampers the accumulation of the foci. On the other hand, the circadian kinase DOUBLETIME (DBT) which phosphorylates PER enhances the accumulation of the foci. LBR likely facilitates PER foci accumulation by destabilizing the catalytic subunit of protein phosphatase 2A, MICROTUBULE STAR (MTS). In conclusion, here, we demonstrate a key role for phosphorylation in promoting the accumulation of PER foci, while LBR modulates this process by impinging on the circadian phosphatase MTS.
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Affiliation(s)
- Mengna Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shujing Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Department of Life Sciences, Bengbu Medical College, Bengbu, Anhui 233030, China
| | - Luoying Zhang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
- Hubei Province Key Laboratory of Oral and Maxillofacial Development and Regeneration, Wuhan, Hubei 430022, China
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7
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ZP3 and AIPL1 participate in GVBD of mouse oocytes by affecting the nuclear membrane localization and maturation of farnesylated prelamin A. ZYGOTE 2023; 31:140-148. [PMID: 36533678 DOI: 10.1017/s0967199422000612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The low maturation rate of oocytes is an important reason for female infertility and failure of assisted pregnancy. The germinal vesicle breakdown (GVBD) is a landmark event of oocyte maturation. In our previous studies, we found that zona pellucida 3 (ZP3) was strongly concentrated in the nuclear region of germinal vesicle (GV) oocytes and interacted with aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) and lamin A to promote GVBD. In the current study, we found that lamin A is mainly concentrated in the nuclear membrane. When ZP3 is knocked down, lamin A will be partially transferred to the nucleus of oocytes. The prelamin A is increased in both the nuclear membrane and nucleus, while phosphorylated lamin A (p-lamin A) is significantly reduced. AIPL1 was also proved to accumulate in the GV region of oocytes, and ZP3 deletion can significantly inhibit the aggregation of AIPL1 in the nuclear region. Similar to ZP3 knockdown, the absence of AIPL1 resulted in a decrease in the occurrence of GVBD, an increase in the amount of prelamin A, and a significant decrease in p-lamin A in oocytes developed in vitro. Finally, we propose the hypothesis that ZP3 can stabilize farnesylated prelamin A on the nuclear membrane of AIPL1, and promote its further processing into mature lamin A, therefore promoting the occurrence of GVBD. This study may be an important supplement for the mechanism of oocyte meiotic resumption and provide new diagnostic targets and treatment clues for infertility patients with oocyte maturation disorder.
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8
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A De Novo Sequence Variant in Barrier-to-Autointegration Factor Is Associated with Dominant Motor Neuronopathy. Cells 2023; 12:cells12060847. [PMID: 36980188 PMCID: PMC10099716 DOI: 10.3390/cells12060847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/23/2023] [Accepted: 02/26/2023] [Indexed: 03/12/2023] Open
Abstract
Barrier-to-autointegration factor (BAF) is an essential component of the nuclear lamina. Encoded by BANF1, this DNA binding protein contributes to the regulation of gene expression, cell cycle progression, and nuclear integrity. A rare recessive BAF variant, Ala12Thr, causes the premature aging syndrome, Néstor–Guillermo progeria syndrome (NGPS). Here, we report the first dominant pathogenic BAF variant, Gly16Arg, identified in a patient presenting with progressive neuromuscular weakness. Although disease variants carry nearby amino acid substitutions, cellular and biochemical properties are distinct. In contrast to NGPS, Gly16Arg patient fibroblasts show modest changes in nuclear lamina structure and increases in repressive marks associated with heterochromatin. Structural studies reveal that the Gly16Arg substitution introduces a salt bridge between BAF monomers, reducing the conformation ensemble available to BAF. We show that this structural change increases the double-stranded DNA binding affinity of BAF Gly16Arg. Together, our findings suggest that BAF Gly16Arg has an increased chromatin occupancy that leads to epigenetic changes and impacts nuclear functions. These observations provide a new example of how a missense mutation can change a protein conformational equilibrium to cause a dominant disease and extend our understanding of mechanisms by which BAF function impacts human health.
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9
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Mendaluk A, Caussinus E, Boutros M, Lehner CF. A genome-wide RNAi screen for genes important for proliferation of cultured Drosophila cells at low temperature identifies the Ball/VRK protein kinase. Chromosoma 2023; 132:31-53. [PMID: 36746786 PMCID: PMC9981717 DOI: 10.1007/s00412-023-00787-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 02/08/2023]
Abstract
A change in ambient temperature is predicted to disrupt cellular homeostasis by affecting all cellular processes in an albeit non-uniform manner. Diffusion is generally less temperature-sensitive than enzymes, for example, and each enzyme has a characteristic individual temperature profile. The actual effects of temperature variation on cells are still poorly understood at the molecular level. Towards an improved understanding, we have performed a genome-wide RNA interference screen with S2R + cells. This Drosophila cell line proliferates over a temperature range comparable to that tolerated by the parental ectothermic organism. Based on effects on cell counts and cell cycle profile after knockdown at 27 and 17 °C, respectively, genes were identified with an apparent greater physiological significance at one or the other temperature. While 27 °C is close to the temperature optimum, the substantially lower 17 °C was chosen to identify genes important at low temperatures, which have received less attention compared to the heat shock response. Among a substantial number of screen hits, we validated a set successfully in cell culture and selected ballchen for further evaluation in the organism. This gene encodes the conserved metazoan VRK protein kinase that is crucial for the release of chromosomes from the nuclear envelope during mitosis. Our analyses in early embryos and larval wing imaginal discs confirmed a higher requirement for ballchen function at temperatures below the optimum. Overall, our experiments validate the genome-wide screen as a basis for future characterizations of genes with increased physiological significance at the lower end of the readily tolerated temperature range.
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Affiliation(s)
- Anna Mendaluk
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
| | - Emmanuel Caussinus
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
| | - Michael Boutros
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg University, BioQuant, Heidelberg, Germany
| | - Christian F Lehner
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland.
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10
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Moreno-Andrés D, Holl K, Antonin W. The second half of mitosis and its implications in cancer biology. Semin Cancer Biol 2023; 88:1-17. [PMID: 36436712 DOI: 10.1016/j.semcancer.2022.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 11/26/2022]
Abstract
The nucleus undergoes dramatic structural and functional changes during cell division. With the entry into mitosis, in human cells the nuclear envelope breaks down, chromosomes rearrange into rod-like structures which are collected and segregated by the spindle apparatus. While these processes in the first half of mitosis have been intensively studied, much less is known about the second half of mitosis, when a functional nucleus reforms in each of the emerging cells. Here we review our current understanding of mitotic exit and nuclear reformation with spotlights on the links to cancer biology.
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Affiliation(s)
- Daniel Moreno-Andrés
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany.
| | - Kristin Holl
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Wolfram Antonin
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
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11
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Archambault V, Li J, Emond-Fraser V, Larouche M. Dephosphorylation in nuclear reassembly after mitosis. Front Cell Dev Biol 2022; 10:1012768. [PMID: 36268509 PMCID: PMC9576876 DOI: 10.3389/fcell.2022.1012768] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
In most animal cell types, the interphase nucleus is largely disassembled during mitotic entry. The nuclear envelope breaks down and chromosomes are compacted into separated masses. Chromatin organization is also mostly lost and kinetochores assemble on centromeres. Mitotic protein kinases play several roles in inducing these transformations by phosphorylating multiple effector proteins. In many of these events, the mechanistic consequences of phosphorylation have been characterized. In comparison, how the nucleus reassembles at the end of mitosis is less well understood in mechanistic terms. In recent years, much progress has been made in deciphering how dephosphorylation of several effector proteins promotes nuclear envelope reassembly, chromosome decondensation, kinetochore disassembly and interphase chromatin organization. The precise roles of protein phosphatases in this process, in particular of the PP1 and PP2A groups, are emerging. Moreover, how these enzymes are temporally and spatially regulated to ensure that nuclear reassembly progresses in a coordinated manner has been partly uncovered. This review provides a global view of nuclear reassembly with a focus on the roles of dephosphorylation events. It also identifies important open questions and proposes hypotheses.
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Affiliation(s)
- Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada
- *Correspondence: Vincent Archambault,
| | - Jingjing Li
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada
| | - Virginie Emond-Fraser
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC, Canada
| | - Myreille Larouche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
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12
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Smith ER, Wang JQ, Yang DH, Xu XX. Paclitaxel Resistance Related to Nuclear Envelope Structural SturdinessRunning Title: Lamin A/C Expression and Paclitaxel Resistance. Drug Resist Updat 2022; 65:100881. [DOI: 10.1016/j.drup.2022.100881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 09/21/2022] [Accepted: 09/21/2022] [Indexed: 11/29/2022]
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13
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Lacroix B, Lorca T, Castro A. Structural, enzymatic and spatiotemporal regulation of PP2A-B55 phosphatase in the control of mitosis. Front Cell Dev Biol 2022; 10:967909. [PMID: 36105360 PMCID: PMC9465306 DOI: 10.3389/fcell.2022.967909] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/04/2022] [Indexed: 11/18/2022] Open
Abstract
Cells require major physical changes to induce a proper repartition of the DNA. Nuclear envelope breakdown, DNA condensation and spindle formation are promoted at mitotic entry by massive protein phosphorylation and reversed at mitotic exit by the timely and ordered dephosphorylation of mitotic substrates. This phosphorylation results from the balance between the activity of kinases and phosphatases. The role of kinases in the control of mitosis has been largely studied, however, the impact of phosphatases has long been underestimated. Recent data have now established that the regulation of phosphatases is crucial to confer timely and ordered cellular events required for cell division. One major phosphatase involved in this process is the phosphatase holoenzyme PP2A-B55. This review will be focused in the latest structural, biochemical and enzymatic insights provided for PP2A-B55 phosphatase as well as its regulators and mechanisms of action.
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Affiliation(s)
- Benjamin Lacroix
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), CNRS UMR5237, Université de Montpellier, CNRS UMR5237Montpellier, France
- Équipe Labellisée “Ligue Nationale Contre le Cancer”, Paris, France
| | - Thierry Lorca
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), CNRS UMR5237, Université de Montpellier, CNRS UMR5237Montpellier, France
- Équipe Labellisée “Ligue Nationale Contre le Cancer”, Paris, France
| | - Anna Castro
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), CNRS UMR5237, Université de Montpellier, CNRS UMR5237Montpellier, France
- Équipe Labellisée “Ligue Nationale Contre le Cancer”, Paris, France
- *Correspondence: Anna Castro,
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14
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Apridita Sebastian W, Shiraishi H, Shimizu N, Umeda R, Lai S, Ikeuchi M, Morisaki I, Yano S, Yoshimura A, Hanada R, Hanada T. Ankle2 deficiency-associated microcephaly and spermatogenesis defects in zebrafish are alleviated by heterozygous deletion of vrk1. Biochem Biophys Res Commun 2022; 624:95-101. [DOI: 10.1016/j.bbrc.2022.07.070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 07/18/2022] [Indexed: 11/02/2022]
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15
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Antonyan L, Ernst C. Putative Roles of SETBP1 Dosage on the SET Oncogene to Affect Brain Development. Front Neurosci 2022; 16:813430. [PMID: 35685777 PMCID: PMC9173722 DOI: 10.3389/fnins.2022.813430] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/19/2022] [Indexed: 12/24/2022] Open
Abstract
Mutations in SET BINDING PROTEIN 1 (SETBP1) cause two different clinically distinguishable diseases called Schinzel–Giedion syndrome (SGS) or SETBP1 deficiency syndrome (SDD). Both disorders are disorders of protein dosage, where SGS is caused by decreased rate of protein breakdown due to mutations in a proteosome targeting domain, and SDD is caused by heterozygous loss-of-function mutations leading to haploinsufficiency. While phenotypes of affected individuals support a role for SETBP1 in brain development, little is known about the mechanisms that might underlie this. The binding partner which gave SETBP1 its name is SET and there is extensive literature on this important oncogene in non-neural tissues. Here we describe different molecular complexes in which SET is involved as well as the role of these complexes in brain development. Based on this information, we postulate how SETBP1 protein dosage might influence these SET-containing molecular pathways and affect brain development. We examine the roles of SET and SETBP1 in acetylation inhibition, phosphatase activity, DNA repair, and cell cycle control. This work provides testable hypotheses for how altered SETBP1 protein dosage affects brain development.
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16
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PP2A-B55: substrates and regulators in the control of cellular functions. Oncogene 2022; 41:1-14. [PMID: 34686773 DOI: 10.1038/s41388-021-02068-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/29/2021] [Accepted: 10/06/2021] [Indexed: 12/17/2022]
Abstract
PP2A is a major serine/threonine phosphatase class involved in the regulation of cell signaling through the removal of protein phosphorylation. This class of phosphatases is comprised of different heterotrimeric complexes displaying distinct substrate specificities. The present review will focus on one specific heterocomplex, the phosphatase PP2A-B55. Herein, we will report the direct substrates of this phosphatase identified to date, and its impact on different cell signaling cascades. We will additionally describe its negative regulation by its inhibitors Arpp19 and ENSA and their upstream kinase Greatwall. Finally, we will describe the essential molecular features defining PP2A-B55 substrate specificity that confer the correct temporal pattern of substrate dephosphorylation. The main objective of this review is to provide the reader with a unique source compiling all the knowledge of this particular holoenzyme that has evolved as a key enzyme for cell homeostasis and cancer development.
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17
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Roubinet C, White IJ, Baum B. Asymmetric nuclear division in neural stem cells generates sibling nuclei that differ in size, envelope composition, and chromatin organization. Curr Biol 2021; 31:3973-3983.e4. [PMID: 34297912 PMCID: PMC8491657 DOI: 10.1016/j.cub.2021.06.063] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 05/12/2021] [Accepted: 06/23/2021] [Indexed: 01/08/2023]
Abstract
Although nuclei are the defining features of eukaryotes, we still do not fully understand how the nuclear compartment is duplicated and partitioned during division. This is especially the case for organisms that do not completely disassemble their nuclear envelope upon entry into mitosis. In studying this process in Drosophila neural stem cells, which undergo asymmetric divisions, we find that the nuclear compartment boundary persists during mitosis thanks to the maintenance of a supporting nuclear lamina. This mitotic nuclear envelope is then asymmetrically remodeled and partitioned to give rise to two daughter nuclei that differ in envelope composition and exhibit a >30-fold difference in volume. The striking difference in nuclear size was found to depend on two consecutive processes: asymmetric nuclear envelope resealing at mitotic exit at sites defined by the central spindle, and differential nuclear growth that appears to depend on the available local reservoir of ER/nuclear membranes, which is asymmetrically partitioned between the two daughter cells. Importantly, these asymmetries in size and composition of the daughter nuclei, and the associated asymmetries in chromatin organization, all become apparent long before the cortical release and the nuclear import of cell fates determinants. Thus, asymmetric nuclear remodeling during stem cell divisions may contribute to the generation of cellular diversity by initiating distinct transcriptional programs in sibling nuclei that contribute to later changes in daughter cell identity and fate.
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Affiliation(s)
- Chantal Roubinet
- MRC Laboratory for Molecular Biology, University College London, London, UK; MRC Laboratory of Molecular Cell Biology, Cambridge, UK.
| | - Ian J White
- MRC Laboratory for Molecular Biology, University College London, London, UK
| | - Buzz Baum
- MRC Laboratory for Molecular Biology, University College London, London, UK; Institute for the Physics of Living Systems, University College London, London, UK; MRC Laboratory of Molecular Cell Biology, Cambridge, UK.
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18
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Larouche M, Kachaner D, Wang P, Normandin K, Garrido D, Yao C, Cormier M, Johansen KM, Johansen J, Archambault V. Spatiotemporal coordination of Greatwall-Endos-PP2A promotes mitotic progression. J Cell Biol 2021; 220:211965. [PMID: 33836042 PMCID: PMC8042607 DOI: 10.1083/jcb.202008145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 02/17/2021] [Accepted: 03/08/2021] [Indexed: 12/31/2022] Open
Abstract
Mitotic entry involves inhibition of protein phosphatase 2A bound to its B55/Tws regulatory subunit (PP2A-B55/Tws), which dephosphorylates substrates of mitotic kinases. This inhibition is induced when Greatwall phosphorylates Endos, turning it into an inhibitor of PP2A-Tws. How this mechanism operates spatiotemporally in the cell is incompletely understood. We previously reported that the nuclear export of Greatwall in prophase promotes mitotic progression. Here, we examine the importance of the localized activities of PP2A-Tws and Endos for mitotic regulation. We find that Tws shuttles through the nucleus via a conserved nuclear localization signal (NLS), but expression of Tws in the cytoplasm and not in the nucleus rescues the development of tws mutants. Moreover, we show that Endos must be in the cytoplasm before nuclear envelope breakdown (NEBD) to be efficiently phosphorylated by Greatwall and to bind and inhibit PP2A-Tws. Disrupting the cytoplasmic function of Endos before NEBD results in subsequent mitotic defects. Evidence suggests that this spatiotemporal regulation is conserved in humans.
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Affiliation(s)
- Myreille Larouche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - David Kachaner
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Peng Wang
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Karine Normandin
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada
| | - Damien Garrido
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Changfu Yao
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA
| | - Maxime Cormier
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada
| | - Kristen M Johansen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA
| | - Jørgen Johansen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA
| | - Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada
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19
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De Jamblinne CV, Decelle B, Dehghani M, Joseph M, Sriskandarajah N, Leguay K, Rambaud B, Lemieux S, Roux PP, Hipfner DR, Carréno S. STRIPAK regulates Slik localization to control mitotic morphogenesis and epithelial integrity. J Cell Biol 2021; 219:152107. [PMID: 32960945 PMCID: PMC7594492 DOI: 10.1083/jcb.201911035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 07/17/2020] [Accepted: 08/20/2020] [Indexed: 02/01/2023] Open
Abstract
Proteins of the ezrin, radixin, and moesin (ERM) family control cell and tissue morphogenesis. We previously reported that moesin, the only ERM in Drosophila, controls mitotic morphogenesis and epithelial integrity. We also found that the Pp1-87B phosphatase dephosphorylates moesin, counteracting its activation by the Ste20-like kinase Slik. To understand how this signaling pathway is itself regulated, we conducted a genome-wide RNAi screen, looking for new regulators of moesin activity. We identified that Slik is a new member of the striatin-interacting phosphatase and kinase complex (STRIPAK). We discovered that the phosphatase activity of STRIPAK reduces Slik phosphorylation to promote its cortical association and proper activation of moesin. Consistent with this finding, inhibition of STRIPAK phosphatase activity causes cell morphology defects in mitosis and impairs epithelial tissue integrity. Our results implicate the Slik–STRIPAK complex in the control of multiple morphogenetic processes.
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Affiliation(s)
- Camille Valérie De Jamblinne
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Barbara Decelle
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada
| | - Mehrnoush Dehghani
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Mathieu Joseph
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Neera Sriskandarajah
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Kévin Leguay
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Basile Rambaud
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Sébastien Lemieux
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Département de Biochimie, Université de Montréal, Montréal, Quebec, Canada
| | - Philippe P Roux
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada.,Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada
| | - David R Hipfner
- Institut de recherches cliniques de Montréal, Montréal, Quebec, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada.,Département de Médecine, Université de Montréal, Montréal, Quebec, Canada
| | - Sébastien Carréno
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada.,Programmes de biologie moléculaire, Université de Montréal, Montréal, Quebec, Canada.,Département de Pathologie et de Biologie Cellulaire, Université de Montréal, Montréal, Quebec, Canada
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20
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Wang P, Yang F, Ma Z, Zhang R. Chromosome Unipolar Division and Low Expression of Tws May Cause Parthenogenesis of Rice Water Weevil ( Lissorhoptrus oryzophilus Kuschel). INSECTS 2021; 12:278. [PMID: 33805047 PMCID: PMC8064085 DOI: 10.3390/insects12040278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 11/28/2022]
Abstract
Rice water weevil (RWW) is divided into two types of population, triploid parthenogenesis and diploid bisexual reproduction. In this study, we explored the meiosis of triploid parthenogenesis RWW (Shangzhuang Town, Haidian District, Beijing, China) by marking the chromosomes and microtubules of parthenogenetic RWW oocytes via immunostaining. The immunostaining results show that there is a canonical meiotic spindle formed in the triploid parthenogenetic RWW oocytes, but chromosomes segregate at only one pole, which means that there is a chromosomal unipolar division during the oogenesis of the parthenogenetic RWW. Furthermore, we cloned the conserved sequences of parthenogenetic RWW REC8 and Tws, and designed primers based on the parthenogenetic RWW sequence to detect expression patterns by quantitative PCR (Q-PCR). Q-PCR results indicate that the expression of REC8 and Tws in ovarian tissue of bisexual Drosophila melanogaster is 0.98 and 10,000.00 times parthenogenetic RWW, respectively (p < 0.01). The results show that Tws had low expression in parthenogenetic RWW ovarian tissue, and REC8 was expressed normally. Our study suggests that the chromosomal unipolar division and deletion of Tws may cause parthenogenesis in RWW.
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Affiliation(s)
- Pengcheng Wang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (P.W.); (F.Y.); (Z.M.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fangyuan Yang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (P.W.); (F.Y.); (Z.M.)
- Department of Entomology, Guizhou University, Guiyang 550025, Guizhou, China
| | - Zhuo Ma
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (P.W.); (F.Y.); (Z.M.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Runzhi Zhang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (P.W.); (F.Y.); (Z.M.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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21
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Karoutas A, Akhtar A. Functional mechanisms and abnormalities of the nuclear lamina. Nat Cell Biol 2021; 23:116-126. [PMID: 33558730 DOI: 10.1038/s41556-020-00630-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 12/22/2020] [Indexed: 01/30/2023]
Abstract
Alterations in nuclear shape are present in human diseases and ageing. A compromised nuclear lamina is molecularly interlinked to altered chromatin functions and genomic instability. Whether these alterations are a cause or a consequence of the pathological state are important questions in biology. Here, we summarize the roles of nuclear envelope components in chromatin organization, phase separation and transcriptional and epigenetic regulation. Examining these functions in healthy backgrounds will guide us towards a better understanding of pathological alterations.
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Affiliation(s)
- Adam Karoutas
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.,Francis Crick Institute, London, UK
| | - Asifa Akhtar
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
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22
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Cyclin B3 activates the Anaphase-Promoting Complex/Cyclosome in meiosis and mitosis. PLoS Genet 2020; 16:e1009184. [PMID: 33137813 PMCID: PMC7660922 DOI: 10.1371/journal.pgen.1009184] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/12/2020] [Accepted: 10/08/2020] [Indexed: 11/19/2022] Open
Abstract
In mitosis and meiosis, chromosome segregation is triggered by the Anaphase-Promoting Complex/Cyclosome (APC/C), a multi-subunit ubiquitin ligase that targets proteins for degradation, leading to the separation of chromatids. APC/C activation requires phosphorylation of its APC3 and APC1 subunits, which allows the APC/C to bind its co-activator Cdc20. The identity of the kinase(s) responsible for APC/C activation in vivo is unclear. Cyclin B3 (CycB3) is an activator of the Cyclin-Dependent Kinase 1 (Cdk1) that is required for meiotic anaphase in flies, worms and vertebrates. It has been hypothesized that CycB3-Cdk1 may be responsible for APC/C activation in meiosis but this remains to be determined. Using Drosophila, we found that mutations in CycB3 genetically enhance mutations in tws, which encodes the B55 regulatory subunit of Protein Phosphatase 2A (PP2A) known to promote mitotic exit. Females heterozygous for CycB3 and tws loss-of-function alleles lay embryos that arrest in mitotic metaphase in a maternal effect, indicating that CycB3 promotes anaphase in mitosis in addition to meiosis. This metaphase arrest is not due to the Spindle Assembly Checkpoint (SAC) because mutation of mad2 that inactivates the SAC does not rescue the development of embryos from CycB3-/+, tws-/+ females. Moreover, we found that CycB3 promotes APC/C activity and anaphase in cells in culture. We show that CycB3 physically associates with the APC/C, is required for phosphorylation of APC3, and promotes APC/C association with its Cdc20 co-activators Fizzy and Cortex. Our results strongly suggest that CycB3-Cdk1 directly activates the APC/C to promote anaphase in both meiosis and mitosis.
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23
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Jacquet K, Rodrigue MA, Richard DE, Lavoie JN. The adenoviral protein E4orf4: a probing tool to decipher mechanical stress-induced nuclear envelope remodeling in tumor cells. Cell Cycle 2020; 19:2963-2981. [PMID: 33103553 DOI: 10.1080/15384101.2020.1836441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The human adenovirus (Ad) type 2/5 early region 4 (E4) ORF4 protein (E4orf4) exerts a remarkable tumor cell-selective killing activity in mammalian cells. This indicates that E4orf4 can target tumor cell-defining features and is a unique tool to probe cancer cell vulnerabilities. Recently, we found that E4orf4, through an interaction with the polarity protein PAR3, subverts nuclear envelope (NE) remodeling processes in a tumor cell-selective manner. In this Perspective, we outline mechanical signals that modify nuclear dynamics and tumor cell behavior to highlight potential mechanisms for E4orf4's tumoricidal activity. Through an analysis of E4orf4's cellular targets, we define a protein subnetwork that comprises phosphatase systems interconnected to polarity protein hubs, which could contribute to enhanced NE plasticity. We infer that elucidating E4orf4's protein network at a functional level could uncover key mechanisms of NE remodeling that define the tumor cell phenotype.
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Affiliation(s)
- Kévin Jacquet
- Centre de Recherche sur le Cancer de l'Université Laval , Québec, Canada.,Oncology, Centre de Recherche du CHU de Québec-Université Laval , Québec, Canada
| | - Marc-Antoine Rodrigue
- Centre de Recherche sur le Cancer de l'Université Laval , Québec, Canada.,Oncology, Centre de Recherche du CHU de Québec-Université Laval , Québec, Canada
| | - Darren E Richard
- Centre de Recherche sur le Cancer de l'Université Laval , Québec, Canada.,Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Université Laval , Québec, Canada.,Endocrinology and Nephrology, Centre de Recherche du CHU de Québec-Université Laval , Québec, Canada
| | - Josée N Lavoie
- Centre de Recherche sur le Cancer de l'Université Laval , Québec, Canada.,Oncology, Centre de Recherche du CHU de Québec-Université Laval , Québec, Canada.,Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Université Laval , Québec, Canada
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24
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Velez-Aguilera G, Nkombo Nkoula S, Ossareh-Nazari B, Link J, Paouneskou D, Van Hove L, Joly N, Tavernier N, Verbavatz JM, Jantsch V, Pintard L. PLK-1 promotes the merger of the parental genome into a single nucleus by triggering lamina disassembly. eLife 2020; 9:59510. [PMID: 33030429 PMCID: PMC7544505 DOI: 10.7554/elife.59510] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/17/2020] [Indexed: 12/15/2022] Open
Abstract
Life of sexually reproducing organisms starts with the fusion of the haploid egg and sperm gametes to form the genome of a new diploid organism. Using the newly fertilized Caenorhabditis elegans zygote, we show that the mitotic Polo-like kinase PLK-1 phosphorylates the lamin LMN-1 to promote timely lamina disassembly and subsequent merging of the parental genomes into a single nucleus after mitosis. Expression of non-phosphorylatable versions of LMN-1, which affect lamina depolymerization during mitosis, is sufficient to prevent the mixing of the parental chromosomes into a single nucleus in daughter cells. Finally, we recapitulate lamina depolymerization by PLK-1 in vitro demonstrating that LMN-1 is a direct PLK-1 target. Our findings indicate that the timely removal of lamin is essential for the merging of parental chromosomes at the beginning of life in C. elegans and possibly also in humans, where a defect in this process might be fatal for embryo development.
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Affiliation(s)
- Griselda Velez-Aguilera
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Sylvia Nkombo Nkoula
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Batool Ossareh-Nazari
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Jana Link
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Dimitra Paouneskou
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Lucie Van Hove
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Nicolas Joly
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Nicolas Tavernier
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | | | - Verena Jantsch
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Lionel Pintard
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
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25
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Torras-Llort M, Medina-Giró S, Escudero-Ferruz P, Lipinszki Z, Moreno-Moreno O, Karman Z, Przewloka MR, Azorín F. A fraction of barrier-to-autointegration factor (BAF) associates with centromeres and controls mitosis progression. Commun Biol 2020; 3:454. [PMID: 32814801 PMCID: PMC7438335 DOI: 10.1038/s42003-020-01182-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 07/30/2020] [Indexed: 01/01/2023] Open
Abstract
Barrier-to-Autointegration Factor (BAF) is a conserved nuclear envelope (NE) component that binds chromatin and helps its anchoring to the NE. Cycles of phosphorylation and dephosphorylation control BAF function. Entering mitosis, phosphorylation releases BAF from chromatin and facilitates NE-disassembly. At mitotic exit, PP2A-mediated dephosphorylation restores chromatin binding and nucleates NE-reassembly. Here, we show that in Drosophila a small fraction of BAF (cenBAF) associates with centromeres. We also find that PP4 phosphatase, which is recruited to centromeres by CENP-C, prevents phosphorylation and release of cenBAF during mitosis. cenBAF is necessary for proper centromere assembly and accurate chromosome segregation, being critical for mitosis progression. Disrupting cenBAF localization prevents PP2A inactivation in mitosis compromising global BAF phosphorylation, which in turn leads to its persistent association with chromatin, delays anaphase onset and causes NE defects. These results suggest that, together with PP4 and CENP-C, cenBAF forms a centromere-based mechanism that controls chromosome segregation and mitosis progression.
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Affiliation(s)
- Mònica Torras-Llort
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain.
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain.
| | - Sònia Medina-Giró
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Paula Escudero-Ferruz
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Zoltan Lipinszki
- MTA SZBK Lendület Laboratory of Cell Cycle Regulation and Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
- Doctoral School of Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Olga Moreno-Moreno
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Zoltan Karman
- MTA SZBK Lendület Laboratory of Cell Cycle Regulation and Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
- Doctoral School of Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Marcin R Przewloka
- School of Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Fernando Azorín
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain.
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain.
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26
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Guo X, Dai X, Wu X, Zhou T, Ni J, Xue J, Wang X. Understanding the birth of rupture-prone and irreparable micronuclei. Chromosoma 2020; 129:181-200. [PMID: 32671520 DOI: 10.1007/s00412-020-00741-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/30/2020] [Accepted: 07/02/2020] [Indexed: 12/17/2022]
Abstract
Micronuclei are extra-nuclear bodies mainly derived from ana-telophase lagging chromosomes/chromatins (LCs) that are not incorporated into primary nuclei at mitotic exit. Unlike primary nuclei, most micronuclei are enclosed by nuclear envelope (NE) that is highly susceptible to spontaneous and irreparable rupture. Ruptured micronuclei act as triggers of chromothripsis-like chaotic chromosomal rearrangements and cGAS-mediated innate immunity and inflammation, raising the view that micronuclei play active roles in human aging and tumorigenesis. Thus, understanding the ways in which micronuclear envelope (mNE) goes awry acquires increased importance. Here, we review the data to present a general framework for this question. We firstly describe NE reassembly after mitosis and NE repair during interphase. Simultaneously, we briefly discuss how mNE is organized and how mNE rupture controls the fate of micronuclei and micronucleated cells. As a focus of this review, we highlight current knowledge about why mNE is rupture-prone and irreparable. For this, we survey observations from a series of elegant studies to provide a systematic overview. We conclude that the birth of rupture-prone and irreparable micronuclei may be the cumulative effects of their intracellular geographic origins, biophysical properties, and specific mNE features. We propose that DNA damage and immunogenicity in micronuclei increase stepwise from altered mNE components, mNE rupture, and refractory to repair. Throughout our discussion, we note interesting issues in mNE fragility that have yet to be resolved.
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Affiliation(s)
- Xihan Guo
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China
| | - Xueqin Dai
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, Yunnan, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, 650204, Yunnan, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Xue Wu
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China
| | - Tao Zhou
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China
| | - Juan Ni
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China
| | - Jinglun Xue
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Xu Wang
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China.
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Duan T, Kitzman SC, Geyer PK. Survival of Drosophila germline stem cells requires the chromatin-binding protein Barrier-to-autointegration factor. Development 2020; 147:dev.186171. [PMID: 32345742 DOI: 10.1242/dev.186171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/31/2020] [Indexed: 11/20/2022]
Abstract
The nuclear lamina (NL) is an extensive protein network that underlies the inner nuclear envelope. This network includes LAP2-emerin-MAN1 domain (LEM-D) proteins that associate with the chromatin and DNA-binding protein Barrier-to-autointegration factor (BAF). Here, we investigate the partnership between three NL Drosophila LEM-D proteins and BAF. In most tissues, only Emerin/Otefin is required for NL enrichment of BAF, revealing an unexpected dependence on a single LEM-D protein. Prompted by these observations, we studied BAF contributions in the ovary, a tissue where Emerin/Otefin function is essential. We show that germ cell-specific BAF knockdown causes phenotypes that mirror emerin/otefin mutants. Loss of BAF disrupts NL structure, blocks differentiation and promotes germ cell loss, phenotypes that are partially rescued by inactivation of the ATR and Chk2 kinases. These data suggest that, similar to emerin/otefin mutants, BAF depletion activates the NL checkpoint that causes germ cell loss. Taken together, our findings provide evidence for a prominent NL partnership between the LEM-D protein Emerin/Otefin and BAF, revealing that BAF functions with this partner in the maintenance of an adult stem cell population.
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Affiliation(s)
- Tingting Duan
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - S Cole Kitzman
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Pamela K Geyer
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
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28
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Boudreau V, Chen R, Edwards A, Sulaimain M, Maddox PS. PP2A-B55/SUR-6 collaborates with the nuclear lamina for centrosome separation during mitotic entry. Mol Biol Cell 2019; 30:876-886. [PMID: 30840554 PMCID: PMC6589783 DOI: 10.1091/mbc.e18-10-0631] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Across most sexually reproducing animals, centrosomes are provided to the oocyte through fertilization and must be positioned properly to establish the zygotic mitotic spindle. How centrosomes are positioned in space and time through the concerted action of key mitotic entry biochemical regulators, including protein phosphatase 2A (PP2A-B55/SUR-6), biophysical regulators, including dynein, and the nuclear lamina is unclear. Here, we uncover a role for PP2A-B55/SUR-6 in regulating centrosome separation. Mechanistically, PP2A-B55/SUR-6 regulates nuclear size before mitotic entry, in turn affecting nuclear envelope–based dynein density and motor capacity. Computational simulations predicted the requirement of PP2A-B55/SUR-6 regulation of nuclear size and nuclear-envelope dynein density for proper centrosome separation. Conversely, compromising nuclear lamina integrity led to centrosome detachment from the nuclear envelope and migration defects. Removal of PP2A-B55/SUR-6 and the nuclear lamina simultaneously further disrupted centrosome separation, leading to unseparated centrosome pairs dissociated from the nuclear envelope. Taking these combined results into consideration, we propose a model in which centrosomes migrate and are positioned through the concerted action of PP2A-B55/SUR-6–regulated nuclear envelope–based dynein pulling forces and centrosome–nuclear envelope tethering. Our results add critical precision to models of centrosome separation relative to the nucleus during spindle formation in cell division.
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Affiliation(s)
- Vincent Boudreau
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
| | - Richard Chen
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
| | - Alan Edwards
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
| | - Muhammad Sulaimain
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
| | - Paul S Maddox
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514
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29
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Moura M, Conde C. Phosphatases in Mitosis: Roles and Regulation. Biomolecules 2019; 9:E55. [PMID: 30736436 PMCID: PMC6406801 DOI: 10.3390/biom9020055] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 02/07/2023] Open
Abstract
Mitosis requires extensive rearrangement of cellular architecture and of subcellular structures so that replicated chromosomes can bind correctly to spindle microtubules and segregate towards opposite poles. This process originates two new daughter nuclei with equal genetic content and relies on highly-dynamic and tightly regulated phosphorylation of numerous cell cycle proteins. A burst in protein phosphorylation orchestrated by several conserved kinases occurs as cells go into and progress through mitosis. The opposing dephosphorylation events are catalyzed by a small set of protein phosphatases, whose importance for the accuracy of mitosis is becoming increasingly appreciated. This review will focus on the established and emerging roles of mitotic phosphatases, describe their structural and biochemical properties, and discuss recent advances in understanding the regulation of phosphatase activity and function.
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Affiliation(s)
- Margarida Moura
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
- i3S-Instituto de Investigação e Inovação em Saúde da Universidade do Porto, 4200-135, Porto, Portugal.
- Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, 4050-313 Porto, Portugal.
| | - Carlos Conde
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
- i3S-Instituto de Investigação e Inovação em Saúde da Universidade do Porto, 4200-135, Porto, Portugal.
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30
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Fowle H, Zhao Z, Graña X. PP2A holoenzymes, substrate specificity driving cellular functions and deregulation in cancer. Adv Cancer Res 2019; 144:55-93. [PMID: 31349904 PMCID: PMC9994639 DOI: 10.1016/bs.acr.2019.03.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PP2A is a highly conserved eukaryotic serine/threonine protein phosphatase of the PPP family of phosphatases with fundamental cellular functions. In cells, PP2A targets specific subcellular locations and substrates by forming heterotrimeric holoenzymes, where a core dimer consisting of scaffold (A) and catalytic (C) subunits complexes with one of many B regulatory subunits. PP2A plays a key role in positively and negatively regulating a myriad of cellular processes, as it targets a very sizable fraction of the cellular substrates phosphorylated on Ser/Thr residues. This review focuses on insights made toward the understanding on how the subunit composition and structure of PP2A holoenzymes mediates substrate specificity, the role of substrate modulation in the signaling of cellular division, growth, and differentiation, and its deregulation in cancer.
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Affiliation(s)
- Holly Fowle
- Fels Institute for Cancer Research and Molecular Biology and Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States
| | - Ziran Zhao
- Fels Institute for Cancer Research and Molecular Biology and Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States
| | - Xavier Graña
- Fels Institute for Cancer Research and Molecular Biology and Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States.
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