1
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Lin J, Sumara I. Cytoplasmic nucleoporin assemblage: the cellular artwork in physiology and disease. Nucleus 2024; 15:2387534. [PMID: 39135336 PMCID: PMC11323873 DOI: 10.1080/19491034.2024.2387534] [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: 05/08/2024] [Revised: 07/29/2024] [Accepted: 07/29/2024] [Indexed: 08/16/2024] Open
Abstract
Nucleoporins, essential proteins building the nuclear pore, are pivotal for ensuring nucleocytoplasmic transport. While traditionally confined to the nuclear envelope, emerging evidence indicates their presence in various cytoplasmic structures, suggesting potential non-transport-related roles. This review consolidates findings on cytoplasmic nucleoporin assemblies across different states, including normal physiological conditions, stress, and pathology, exploring their structural organization, formation dynamics, and functional implications. We summarize the current knowledge and the latest concepts on the regulation of nucleoporin homeostasis, aiming to enhance our understanding of their unexpected roles in physiological and pathological processes.
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Affiliation(s)
- Junyan Lin
- Department of Development and Stem Cells, Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France
- Centre National de la Recherche Scientifique UMR 7104, Strasbourg, France
- Institut National de la Santé et de la Recherche Médicale U964, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Izabela Sumara
- Department of Development and Stem Cells, Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France
- Centre National de la Recherche Scientifique UMR 7104, Strasbourg, France
- Institut National de la Santé et de la Recherche Médicale U964, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
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2
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Penzo A, Palancade B. Puzzling out nuclear pore complex assembly. FEBS Lett 2023; 597:2705-2727. [PMID: 37548888 DOI: 10.1002/1873-3468.14713] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/12/2023] [Accepted: 07/17/2023] [Indexed: 08/08/2023]
Abstract
Nuclear pore complexes (NPCs) are sophisticated multiprotein assemblies embedded within the nuclear envelope and controlling the exchanges of molecules between the cytoplasm and the nucleus. In this review, we summarize the mechanisms by which these elaborate complexes are built from their subunits, the nucleoporins, based on our ever-growing knowledge of NPC structural organization and on the recent identification of additional features of this process. We present the constraints faced during the production of nucleoporins, their gathering into oligomeric complexes, and the formation of NPCs within nuclear envelopes, and review the cellular strategies at play, from co-translational assembly to the enrolment of a panel of cofactors. Remarkably, the study of NPCs can inform our perception of the biogenesis of multiprotein complexes in general - and vice versa.
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Affiliation(s)
- Arianna Penzo
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Benoit Palancade
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
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3
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de Oya IG, Manzano-López J, Álvarez-Llamas A, Vázquez-Aroca MDLP, Cepeda-García C, Monje-Casas F. Characterization of a novel interaction of the Nup159 nucleoporin with asymmetrically localized spindle pole body proteins and its link with autophagy. PLoS Biol 2023; 21:e3002224. [PMID: 37535687 PMCID: PMC10437821 DOI: 10.1371/journal.pbio.3002224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/18/2023] [Accepted: 06/28/2023] [Indexed: 08/05/2023] Open
Abstract
Both the spindle microtubule-organizing centers and the nuclear pore complexes (NPCs) are convoluted structures where many signaling pathways converge to coordinate key events during cell division. Interestingly, despite their distinct molecular conformation and overall functions, these structures share common components and collaborate in the regulation of essential processes. We have established a new link between microtubule-organizing centers and nuclear pores in budding yeast by unveiling an interaction between the Bfa1/Bub2 complex, a mitotic exit inhibitor that localizes on the spindle pole bodies, and the Nup159 nucleoporin. Bfa1/Bub2 association with Nup159 is reduced in metaphase to not interfere with proper spindle positioning. However, their interaction is stimulated in anaphase and assists the Nup159-dependent autophagy pathway. The asymmetric localization of Bfa1/Bub2 during mitosis raises the possibility that its interaction with Nup159 could differentially promote Nup159-mediated autophagic processes, which might be relevant for the maintenance of the replicative lifespan.
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Affiliation(s)
- Inés García de Oya
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Javier Manzano-López
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Alejandra Álvarez-Llamas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - María de la Paz Vázquez-Aroca
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Cristina Cepeda-García
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
| | - Fernando Monje-Casas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) / Spanish National Research Council (CSIC) - University of Seville - University Pablo de Olavide, Sevilla, Spain
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4
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Ong JY, Torres JZ. Cul3 substrate adaptor SPOP targets Nup153 for degradation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.13.540659. [PMID: 37293018 PMCID: PMC10245568 DOI: 10.1101/2023.05.13.540659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
SPOP is a Cul3 substrate adaptor responsible for degradation of many proteins related to cell growth and proliferation. Because mutation or misregulation of SPOP drives cancer progression, understanding the suite of SPOP substrates is important to understanding regulation of cell proliferation. Here, we identify Nup153, a component of the nuclear basket of the nuclear pore complex, as a novel substrate of SPOP. SPOP and Nup153 bind to each other and colocalize at the nuclear envelope and some nuclear foci in cells. The binding interaction between SPOP and Nup153 is complex and multivalent. Nup153 is ubiquitylated and degraded upon expression of SPOPWT but not its substrate binding-deficient mutant SPOPF102C. Depletion of SPOP via RNAi leads to Nup153 stabilization. Upon loss of SPOP, the nuclear envelope localization of spindle assembly checkpoint protein Mad1, which is tethered to the nuclear envelope by Nup153, is stronger. Altogether, our results demonstrate SPOP regulates Nup153 levels and expands our understanding of the role of SPOP in protein and cellular homeostasis.
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Affiliation(s)
- Joseph Y Ong
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jorge Z Torres
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA 90095, USA
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5
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Singh U, Bindra D, Samaiya A, Mishra RK. Overexpressed Nup88 stabilized through interaction with Nup62 promotes NF-κB dependent pathways in cancer. Front Oncol 2023; 13:1095046. [PMID: 36845732 PMCID: PMC9947638 DOI: 10.3389/fonc.2023.1095046] [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: 11/10/2022] [Accepted: 01/16/2023] [Indexed: 02/11/2023] Open
Abstract
Bidirectional nucleo-cytoplasmic transport, regulating several vital cellular processes, is mediated by the Nuclear Pore Complex (NPC) comprising the nucleoporin (Nup) proteins. Nup88, a constituent nucleoporin, is overexpressed in many cancers, and a positive correlation exists between progressive stages of cancer and Nup88 levels. While a significant link of Nup88 overexpression in head and neck cancer exists but mechanistic details of Nup88 roles in tumorigenesis are sparse. Here, we report that Nup88 and Nup62 levels are significantly elevated in head and neck cancer patient samples and cell lines. We demonstrate that the elevated levels of Nup88 or Nup62 impart proliferation and migration advantages to cells. Interestingly, Nup88-Nup62 engage in a strong interaction independent of Nup-glycosylation status and cell-cycle stages. We report that the interaction with Nup62 stabilizes Nup88 by inhibiting the proteasome-mediated degradation of overexpressed Nup88. Overexpressed Nup88 stabilized by interaction with Nup62 can interact with NF-κB (p65) and sequesters p65 partly into nucleus of unstimulated cells. NF-κB targets like Akt, c-myc, IL-6 and BIRC3 promoting proliferation and growth are induced under Nup88 overexpression conditions. In conclusion, our data indicates that simultaneous overexpression of Nup62 and Nup88 in head and neck cancer stabilizes Nup88. Stabilized Nup88 interacts and activates p65 pathway, which perhaps is the underlying mechanism in Nup88 overexpressing tumors.
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Affiliation(s)
- Usha Singh
- Nups and Sumo Biology Group, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh, India
| | - Divya Bindra
- Nups and Sumo Biology Group, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh, India
| | - Atul Samaiya
- Department of Surgical Oncology, Bansal Hospital, Bhopal, Madhya Pradesh, India
| | - Ram Kumar Mishra
- Nups and Sumo Biology Group, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, Madhya Pradesh, India,*Correspondence: Ram Kumar Mishra,
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6
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Dultz E, Wojtynek M, Medalia O, Onischenko E. The Nuclear Pore Complex: Birth, Life, and Death of a Cellular Behemoth. Cells 2022; 11:1456. [PMID: 35563762 PMCID: PMC9100368 DOI: 10.3390/cells11091456] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/22/2022] [Accepted: 04/23/2022] [Indexed: 02/01/2023] Open
Abstract
Nuclear pore complexes (NPCs) are the only transport channels that cross the nuclear envelope. Constructed from ~500-1000 nucleoporin proteins each, they are among the largest macromolecular assemblies in eukaryotic cells. Thanks to advances in structural analysis approaches, the construction principles and architecture of the NPC have recently been revealed at submolecular resolution. Although the overall structure and inventory of nucleoporins are conserved, NPCs exhibit significant compositional and functional plasticity even within single cells and surprising variability in their assembly pathways. Once assembled, NPCs remain seemingly unexchangeable in post-mitotic cells. There are a number of as yet unresolved questions about how the versatility of NPC assembly and composition is established, how cells monitor the functional state of NPCs or how they could be renewed. Here, we review current progress in our understanding of the key aspects of NPC architecture and lifecycle.
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Affiliation(s)
- Elisa Dultz
- Institute of Biochemistry, Department of Biology, ETHZ Zurich, 8093 Zurich, Switzerland;
| | - Matthias Wojtynek
- Institute of Biochemistry, Department of Biology, ETHZ Zurich, 8093 Zurich, Switzerland;
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland;
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland;
| | - Evgeny Onischenko
- Department of Biological Sciences, University of Bergen, 5020 Bergen, Norway
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7
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Raices M, D'Angelo MA. Structure, Maintenance, and Regulation of Nuclear Pore Complexes: The Gatekeepers of the Eukaryotic Genome. Cold Spring Harb Perspect Biol 2022; 14:a040691. [PMID: 34312247 PMCID: PMC8789946 DOI: 10.1101/cshperspect.a040691] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In eukaryotic cells, the genetic material is segregated inside the nucleus. This compartmentalization of the genome requires a transport system that allows cells to move molecules across the nuclear envelope, the membrane-based barrier that surrounds the chromosomes. Nuclear pore complexes (NPCs) are the central component of the nuclear transport machinery. These large protein channels penetrate the nuclear envelope, creating a passage between the nucleus and the cytoplasm through which nucleocytoplasmic molecule exchange occurs. NPCs are one of the largest protein assemblies of eukaryotic cells and, in addition to their critical function in nuclear transport, these structures also play key roles in many cellular processes in a transport-independent manner. Here we will review the current knowledge of the NPC structure, the cellular mechanisms that regulate their formation and maintenance, and we will provide a brief description of a variety of processes that NPCs regulate.
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Affiliation(s)
- Marcela Raices
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, USA
| | - Maximiliano A D'Angelo
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, USA
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8
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Dargemont C. Analysis of Ubiquitylation and SUMOylation of Yeast Nuclear Pore Complex Proteins. Methods Mol Biol 2022; 2502:259-269. [PMID: 35412244 DOI: 10.1007/978-1-0716-2337-4_17] [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] [Indexed: 06/14/2023]
Abstract
Posttranslational modifications and in particular ubiquitylation and SUMOylation of the nuclear pore complex (NPC), have been shown to regulate some of its functions, particularly in response to diverse stress signals.Although proteomic approaches are extremely powerful to identify substrates and modification sites, dissecting specific mechanisms and regulation functions of ubiquitylation and SUMOylation of the diverse NPC proteins, in different genetic backgrounds or cell environmental conditions, requires specific biochemical assays based on purification and precise analysis of 6His-tagged ubiquitylated or SUMOylated protein of interest. Here we describe an approach that can be easily employed without specific equipment. It allowed to successfully analyze yeast NPC proteins but can easily be adapted to the study of the mammalian NPC.
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Affiliation(s)
- Catherine Dargemont
- Institut de Génétique Humaine, Université de Montpellier, Laboratoire de Virologie Moléculaire CNRS-UMR9002, Montpellier, France.
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9
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Tomioka Y, Kotani T, Kirisako H, Oikawa Y, Kimura Y, Hirano H, Ohsumi Y, Nakatogawa H. TORC1 inactivation stimulates autophagy of nucleoporin and nuclear pore complexes. J Cell Biol 2021; 219:151819. [PMID: 32453403 PMCID: PMC7337488 DOI: 10.1083/jcb.201910063] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/05/2020] [Accepted: 04/20/2020] [Indexed: 02/08/2023] Open
Abstract
The mechanisms underlying turnover of the nuclear pore complex (NPC) and the component nucleoporins (Nups) are still poorly understood. In this study, we found that the budding yeast Saccharomyces cerevisiae triggers NPC degradation by autophagy upon the inactivation of Tor kinase complex 1. This degradation largely depends on the selective autophagy-specific factor Atg11 and the autophagy receptor-binding ability of Atg8, suggesting that the NPC is degraded via receptor-dependent selective autophagy. Immunoelectron microscopy revealed that NPCs embedded in nuclear envelope-derived double-membrane vesicles are sequestered within autophagosomes. At least two pathways are involved in NPC degradation: Atg39-dependent nucleophagy (selective autophagy of the nucleus) and a pathway involving an unknown receptor. In addition, we found the interaction between Nup159 and Atg8 via the Atg8-family interacting motif is important for degradation of this nucleoporin not assembled into the NPC. Thus, this study provides the first evidence for autophagic degradation of the NPC and Nups, which we term "NPC-phagy" and "nucleoporinophagy."
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Affiliation(s)
- Yui Tomioka
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Tetsuya Kotani
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiromi Kirisako
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yu Oikawa
- Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Yayoi Kimura
- Advanced Medical Research Center, Yokohama City University, Yokohama, Japan
| | - Hisashi Hirano
- Advanced Medical Research Center, Yokohama City University, Yokohama, Japan
| | - Yoshinori Ohsumi
- Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Hitoshi Nakatogawa
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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10
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Eyboulet F, Jeronimo C, Côté J, Robert F. The deubiquitylase Ubp15 couples transcription to mRNA export. eLife 2020; 9:e61264. [PMID: 33226341 PMCID: PMC7682988 DOI: 10.7554/elife.61264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/04/2020] [Indexed: 12/16/2022] Open
Abstract
Nuclear export of messenger RNAs (mRNAs) is intimately coupled to their synthesis. pre-mRNAs assemble into dynamic ribonucleoparticles as they are being transcribed, processed, and exported. The role of ubiquitylation in this process is increasingly recognized but, while a few E3 ligases have been shown to regulate nuclear export, evidence for deubiquitylases is currently lacking. Here we identified deubiquitylase Ubp15 as a regulator of nuclear export in Saccharomyces cerevisiae. Ubp15 interacts with both RNA polymerase II and the nuclear pore complex, and its deletion reverts the nuclear export defect of E3 ligase Rsp5 mutants. The deletion of UBP15 leads to hyper-ubiquitylation of the main nuclear export receptor Mex67 and affects its association with THO, a complex coupling transcription to mRNA processing and involved in the recruitment of mRNA export factors to nascent transcripts. Collectively, our data support a role for Ubp15 in coupling transcription to mRNA export.
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Affiliation(s)
- Fanny Eyboulet
- Institut de recherches cliniques de MontréalMontréalCanada
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Axe Oncologie du Centre de Recherche du CHU de Québec-Université LavalQuébec CityCanada
| | - Célia Jeronimo
- Institut de recherches cliniques de MontréalMontréalCanada
| | - Jacques Côté
- St-Patrick Research Group in Basic Oncology, Laval University Cancer Research Center, Axe Oncologie du Centre de Recherche du CHU de Québec-Université LavalQuébec CityCanada
| | - François Robert
- Institut de recherches cliniques de MontréalMontréalCanada
- Département de Médecine, Faculté de Médecine, Université de MontréalMontréalCanada
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11
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Folz H, Niño CA, Taranum S, Caesar S, Latta L, Waharte F, Salamero J, Schlenstedt G, Dargemont C. SUMOylation of the nuclear pore complex basket is involved in sensing cellular stresses. J Cell Sci 2019; 132:jcs.224279. [PMID: 30837289 PMCID: PMC6467484 DOI: 10.1242/jcs.224279] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 02/22/2019] [Indexed: 01/02/2023] Open
Abstract
The nuclear pore complex (NPC) is the major conduit for nucleocytoplasmic transport and serves as a platform for gene regulation and DNA repair. Several nucleoporins undergo ubiquitylation and SUMOylation, and these modifications play an important role in nuclear pore dynamics and plasticity. Here, we perform a detailed analysis of these post-translational modifications of yeast nuclear basket proteins under normal growth conditions as well as upon cellular stresses, with a focus on SUMOylation. We find that the balance between the dynamics of SUMOylation and deSUMOylation of Nup60 and Nup2 at the NPC differs substantially, particularly in G1 and S phase. While Nup60 is the unique target of genotoxic stress within the nuclear basket that probably belongs to the SUMO-mediated DNA damage response pathway, both Nup2 and Nup60 show a dramatic increase in SUMOylation upon osmotic stress, with Nup2 SUMOylation being enhanced in Nup60 SUMO-deficient mutant yeast strains. Taken together, our data reveal that there are several levels of crosstalk between nucleoporins, and that the post-translational modifications of the NPC serve in sensing cellular stress signals. Summary: Post-translational modifications, and in particular SUMOylation, of the nuclear basket subcomplex of the nuclear pore complex serve in its function as a sensor for mediating cellular stress signals.
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Affiliation(s)
- Hanne Folz
- Institute of Medical Biochemistry and Molecular Biology, Universität des Saarlandes, D-66421 Homburg, Germany
| | - Carlos A Niño
- Université Paris Diderot, Sorbonne Paris Cité, Pathologie et Virologie Moléculaire, INSERM, CNRS, Hôpital St. Louis, 75475 Paris, France
| | - Surayya Taranum
- Université Paris Diderot, Sorbonne Paris Cité, Pathologie et Virologie Moléculaire, INSERM, CNRS, Hôpital St. Louis, 75475 Paris, France
| | - Stefanie Caesar
- Institute of Medical Biochemistry and Molecular Biology, Universität des Saarlandes, D-66421 Homburg, Germany
| | - Lorenz Latta
- Institute of Medical Biochemistry and Molecular Biology, Universität des Saarlandes, D-66421 Homburg, Germany
| | - François Waharte
- Institut Curie, PSL Research University, CNRS UMR 144, UPMC, Space-time Imaging of Organelles and Endomembranes Dynamics & PICT-IBiSA Imaging Core Facility, 75005 Paris, France
| | - Jean Salamero
- Institut Curie, PSL Research University, CNRS UMR 144, UPMC, Space-time Imaging of Organelles and Endomembranes Dynamics & PICT-IBiSA Imaging Core Facility, 75005 Paris, France
| | - Gabriel Schlenstedt
- Institute of Medical Biochemistry and Molecular Biology, Universität des Saarlandes, D-66421 Homburg, Germany
| | - Catherine Dargemont
- Université Paris Diderot, Sorbonne Paris Cité, Pathologie et Virologie Moléculaire, INSERM, CNRS, Hôpital St. Louis, 75475 Paris, France
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12
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Pappas SS, Liang CC, Kim S, Rivera CO, Dauer WT. TorsinA dysfunction causes persistent neuronal nuclear pore defects. Hum Mol Genet 2019; 27:407-420. [PMID: 29186574 DOI: 10.1093/hmg/ddx405] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 11/15/2017] [Indexed: 01/09/2023] Open
Abstract
A critical challenge to deciphering the pathophysiology of neurodevelopmental disease is identifying which of the myriad abnormalities that emerge during CNS maturation persist to contribute to long-term brain dysfunction. Childhood-onset dystonia caused by a loss-of-function mutation in the AAA+ protein torsinA exemplifies this challenge. Neurons lacking torsinA develop transient nuclear envelope (NE) malformations during CNS maturation, but no NE defects are described in mature torsinA null neurons. We find that during postnatal CNS maturation torsinA null neurons develop mislocalized and dysfunctional nuclear pore complexes (NPC) that lack NUP358, normally added late in NPC biogenesis. SUN1, a torsinA-related molecule implicated in interphase NPC biogenesis, also exhibits localization abnormalities. Whereas SUN1 and associated nuclear membrane abnormalities resolve in juvenile mice, NPC defects persist into adulthood. These findings support a role for torsinA function in NPC biogenesis during neuronal maturation and implicate altered NPC function in dystonia pathophysiology.
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Affiliation(s)
| | | | - Sumin Kim
- Cellular and Molecular Biology Program
| | | | - William T Dauer
- Department of Neurology.,Cellular and Molecular Biology Program.,Department of Cell and Developmental Biology.,VA Ann Arbor Health System, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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13
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Mehrtash AB, Hochstrasser M. Ubiquitin-dependent protein degradation at the endoplasmic reticulum and nuclear envelope. Semin Cell Dev Biol 2018; 93:111-124. [PMID: 30278225 DOI: 10.1016/j.semcdb.2018.09.013] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/26/2018] [Accepted: 09/27/2018] [Indexed: 01/01/2023]
Abstract
Numerous nascent proteins undergo folding and maturation within the luminal and membrane compartments of the endoplasmic reticulum (ER). Despite the presence of various factors in the ER that promote protein folding, many proteins fail to properly fold and assemble and are subsequently degraded. Regulatory proteins in the ER also undergo degradation in a way that is responsive to stimuli or the changing needs of the cell. As in most cellular compartments, the ubiquitin-proteasome system (UPS) is responsible for the majority of the degradation at the ER-in a process termed ER-associated degradation (ERAD). Autophagic processes utilizing ubiquitin-like protein-conjugating systems also play roles in protein degradation at the ER. The ER is continuous with the nuclear envelope (NE), which consists of the outer nuclear membrane (ONM) and inner nuclear membrane (INM). While ERAD is known also to occur at the NE, only some of the ERAD ubiquitin-ligation pathways function at the INM. Protein degradation machineries in the ER/NE target a wide variety of substrates in multiple cellular compartments, including the cytoplasm, nucleoplasm, ER lumen, ER membrane, and the NE. Here, we review the protein degradation machineries of the ER and NE and the underlying mechanisms dictating recognition and processing of substrates by these machineries.
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Affiliation(s)
- Adrian B Mehrtash
- Department of Molecular, Cellular, & Developmental Biology, Yale University, New Haven, 06520, CT, USA.
| | - Mark Hochstrasser
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, 06520, USA; Department of Molecular, Cellular, & Developmental Biology, Yale University, New Haven, 06520, CT, USA.
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14
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Manhas S, Ma L, Measday V. The yeast Ty1 retrotransposon requires components of the nuclear pore complex for transcription and genomic integration. Nucleic Acids Res 2018; 46:3552-3578. [PMID: 29514267 PMCID: PMC5909446 DOI: 10.1093/nar/gky109] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 02/01/2018] [Accepted: 02/26/2018] [Indexed: 01/06/2023] Open
Abstract
Nuclear pore complexes (NPCs) orchestrate cargo between the cytoplasm and nucleus and regulate chromatin organization. NPC proteins, or nucleoporins (Nups), are required for human immunodeficiency virus type 1 (HIV-1) gene expression and genomic integration of viral DNA. We utilize the Ty1 retrotransposon of Saccharomyces cerevisiae (S. cerevisiae) to study retroviral integration because retrotransposons are the progenitors of retroviruses and have conserved integrase (IN) enzymes. Ty1-IN targets Ty1 elements into the genome upstream of RNA polymerase (Pol) III transcribed genes such as transfer RNA (tRNA) genes. Evidence that S. cerevisiae tRNA genes are recruited to NPCs prompted our investigation of a functional role for the NPC in Ty1 targeting into the genome. We find that Ty1 mobility is reduced in multiple Nup mutants that cannot be accounted for by defects in Ty1 gene expression, cDNA production or Ty1-IN nuclear entry. Instead, we find that Ty1 insertion upstream of tRNA genes is impaired. We also identify Nup mutants with wild type Ty1 mobility but impaired Ty1 targeting. The NPC nuclear basket, which interacts with chromatin, is required for both Ty1 expression and nucleosome targeting. Deletion of components of the NPC nuclear basket causes mis-targeting of Ty1 elements to the ends of chromosomes.
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Affiliation(s)
- Savrina Manhas
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Centre, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Lina Ma
- Wine Research Centre, 2205 East Mall, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Vivien Measday
- Department of Biochemistry and Molecular Biology, 2350 Health Sciences Mall, Life Sciences Centre, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
- Wine Research Centre, 2205 East Mall, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
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15
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The chromatin remodeling Isw1a complex is regulated by SUMOylation. Biochem J 2017; 474:3455-3469. [PMID: 28899943 DOI: 10.1042/bcj20170172] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 08/29/2017] [Accepted: 09/08/2017] [Indexed: 12/28/2022]
Abstract
The ISWI class of proteins consists of a family of chromatin remodeling ATPases that is ubiquitous in eukaryotes and predominantly functions to slide nucleosomes laterally. The yeast Saccharomyces cerevisiae Isw1 partners with several non-essential alternative subunits - Ioc2, Ioc3, or Ioc4 - to form two distinct complexes Isw1a and Isw1b. Besides its ATPase domain, Isw1 presents a C-terminal region formed by HAND, SANT, and SLIDE domains responsible for interaction with the Ioc proteins and optimal association of Isw1 to chromatin. Despite diverse studies on the functions of the Isw1-containing complexes, molecular evidence for a regulation of this chromatin remodeling ATPase is still elusive. Results presented here indicate that Isw1 is not only ubiquitylated but also strongly SUMOylated on multiple lysine residues by the redundant Siz1/Siz2 SUMO E3 ligases. However, Isw1 is a poor substrate of the Ulp1 and Ulp2 SUMO proteases, thus resulting in a high level of modification. Extensive site-directed mutagenesis allowed us to identify the major SUMOylation sites and develop a SUMO-defective mutant of Isw1. Using this molecular tool, we show that SUMOylation of Isw1 specifically facilitates and/or stabilizes its interaction with its cofactor Ioc3 and consequently the efficient recruitment of the Isw1-Ioc3 complex onto chromatin. Together these data reveal a new regulatory mechanism for this fascinating remodeling factor.
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16
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Domanska A, Kaminska J. Role of Rsp5 ubiquitin ligase in biogenesis of rRNA, mRNA and tRNA in yeast. RNA Biol 2016; 12:1265-74. [PMID: 26403176 DOI: 10.1080/15476286.2015.1094604] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Rsp5 ubiquitin ligase is required for ubiquitination of a wide variety of proteins involved in essential processes. Rsp5 was shown to be involved in regulation of lipid biosynthesis, intracellular trafficking of proteins, response to various stresses, and many other processes. In this article, we provide a comprehensive review of the nuclear and cytoplasmic functions of Rsp5 with a focus on biogenesis of different RNAs. We also briefly describe the participation of Rsp5 in the regulation of the RNA polymerase II complex, and its potential role in the regulation of other RNA polymerases. Moreover, we emphasize the function of Rsp5 in the coordination of the different steps of rRNA, mRNA and tRNA metabolism in the context of protein biosynthesis. Finally, we highlight the involvement of Rsp5 in controlling diverse cellular mechanisms at multiple levels and in adaptation of the cell to changing growth conditions.
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Affiliation(s)
- Anna Domanska
- a Institute of Biochemistry and Biophysics, Polish Academy of Sciences ; Warsaw , Poland
| | - Joanna Kaminska
- a Institute of Biochemistry and Biophysics, Polish Academy of Sciences ; Warsaw , Poland
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17
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Abstract
The nuclear pore complex (NPC) mediates the shuttle transport of macromolecules between the nucleus and cytoplasm in eukaryotic cells. The permeability barrier formed by intrinsically disordered phenylalanine-glycine-rich nucleoporins (FG-Nups) in the NPC functions as the critical selective control for nucleocytoplasmic transport. Signal-independent small molecules (< 40 kDa) passively diffuse through the pore, but passage of large cargo molecules is inhibited unless they are chaperoned by nuclear transport receptors (NTRs). NTRs are capable of interacting with FG-Nups and guide the cargos to cross the barrier by facilitated diffusion. The native conformation of the FG-Nups permeability barrier and the competition among multiple NTRs interacting with this barrier in the native NPCs are the 2 core questions still being highly debated in the field. Recently, we applied high-speed super-resolution fluorescence microscopy to map out the natural structure of the FG-Nups barrier and determined the competition among multiple NTRs as they interact with the barrier in the native NPCs. In this extra-view article, we will review the current understanding in the configuration and function of FG-Nups barrier and highlight the new evidence obtained recently to answer the core questions in nucleocytoplasmic transport.
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Affiliation(s)
- Christina Li
- a Department of Biology , Temple University , Philadelphia , PA , USA
| | | | - Weidong Yang
- a Department of Biology , Temple University , Philadelphia , PA , USA
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18
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Jöhnk B, Bayram Ö, Abelmann A, Heinekamp T, Mattern DJ, Brakhage AA, Jacobsen ID, Valerius O, Braus GH. SCF Ubiquitin Ligase F-box Protein Fbx15 Controls Nuclear Co-repressor Localization, Stress Response and Virulence of the Human Pathogen Aspergillus fumigatus. PLoS Pathog 2016; 12:e1005899. [PMID: 27649508 PMCID: PMC5029927 DOI: 10.1371/journal.ppat.1005899] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 08/26/2016] [Indexed: 01/27/2023] Open
Abstract
F-box proteins share the F-box domain to connect substrates of E3 SCF ubiquitin RING ligases through the adaptor Skp1/A to Cul1/A scaffolds. F-box protein Fbx15 is part of the general stress response of the human pathogenic mold Aspergillus fumigatus. Oxidative stress induces a transient peak of fbx15 expression, resulting in 3x elevated Fbx15 protein levels. During non-stress conditions Fbx15 is phosphorylated and F-box mediated interaction with SkpA preferentially happens in smaller subpopulations in the cytoplasm. The F-box of Fbx15 is required for an appropriate oxidative stress response, which results in rapid dephosphorylation of Fbx15 and a shift of the cellular interaction with SkpA to the nucleus. Fbx15 binds SsnF/Ssn6 as part of the RcoA/Tup1-SsnF/Ssn6 co-repressor and is required for its correct nuclear localization. Dephosphorylated Fbx15 prevents SsnF/Ssn6 nuclear localization and results in the derepression of gliotoxin gene expression. fbx15 deletion mutants are unable to infect immunocompromised mice in a model for invasive aspergillosis. Fbx15 has a novel dual molecular function by controlling transcriptional repression and being part of SCF E3 ubiquitin ligases, which is essential for stress response, gliotoxin production and virulence in the opportunistic human pathogen A. fumigatus. The opportunistic human fungal pathogen Aspergillus fumigatus is the most prevalent cause for severe fungal infections in immunocompromised hosts. A major virulence factor of A. fumigatus is its ability to rapidly adapt to host conditions during infection. The rapid response to environmental changes underlies a well-balanced system of production and degradation of proteins. The degradation of specific target proteins is mediated by ubiquitin-protein ligases (E3), which mark their target proteins with ubiquitin for proteasomal degradation. Multisubunit SCF Cullin1 Ring ligases (CRL) are E3 ligases where the F-box subunit functions as a substrate-specificity determining adaptor. A comprehensive control of protein production includes global co-repressors as the conserved Ssn6(SsnF)-Tup1(RcoA) complex, which reduces transcription on multiple levels. We have identified a novel connection between protein degradation and synthesis through an F-box protein. Fbx15 can be incorporated into SCF E3 ubiquitin ligases and controls upon stress the nuclear localization of the SsnF. Fbx15 plays a critical role for A. fumigatus adaptation and is essential for virulence in a murine infection model. Fbx15 is a fungal-specific protein and therefore a potential target for future drug development.
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Affiliation(s)
- Bastian Jöhnk
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, Göttingen, Germany
| | - Özgür Bayram
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, Göttingen, Germany
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, County Kildare, Ireland
| | - Anja Abelmann
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, Göttingen, Germany
| | - Thorsten Heinekamp
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Friedrich Schiller University, Jena, Germany
| | - Derek J. Mattern
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Friedrich Schiller University, Jena, Germany
| | - Axel A. Brakhage
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Friedrich Schiller University, Jena, Germany
| | - Ilse D. Jacobsen
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Friedrich Schiller University, Jena, Germany
| | - Oliver Valerius
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, Göttingen, Germany
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics and Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, Göttingen, Germany
- * E-mail:
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19
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Niño CA, Guet D, Gay A, Brutus S, Jourquin F, Mendiratta S, Salamero J, Géli V, Dargemont C. Posttranslational marks control architectural and functional plasticity of the nuclear pore complex basket. J Cell Biol 2016; 212:167-80. [PMID: 26783300 PMCID: PMC4738382 DOI: 10.1083/jcb.201506130] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Ubiquitin modifications of the nuclear pore complex (NPC) control the architectural plasticity of the nuclear basket, contributing to its tethering to the core NPC, with consequences on the cellular response to DNA damage and telomere recombination. The nuclear pore complex (NPC) serves as both the unique gate between the nucleus and the cytoplasm and a major platform that coordinates nucleocytoplasmic exchanges, gene expression, and genome integrity. To understand how the NPC integrates these functional constraints, we dissected here the posttranslational modifications of the nuclear basket protein Nup60 and analyzed how they intervene to control the plasticity of the NPC. Combined approaches highlight the role of monoubiquitylation in regulating the association dynamics of Nup60 and its partner, Nup2, with the NPC through an interaction with Nup84, a component of the Y complex. Although major nuclear transport routes are not regulated by Nup60 modifications, monoubiquitylation of Nup60 is stimulated upon genotoxic stress and regulates the DNA-damage response and telomere repair. Together, these data reveal an original mechanism contributing to the plasticity of the NPC at a molecular-organization and functional level.
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Affiliation(s)
- Carlos A Niño
- University Paris Diderot, Sorbonne Paris Cité, Pathologie et Virologie Moléculaire, Institut National de la Santé et de la Recherche Medicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Equipe labellisée Ligue contre le cancer, Hôpital St. Louis, 75475 Paris, France
| | - David Guet
- University Paris Diderot, Sorbonne Paris Cité, Pathologie et Virologie Moléculaire, Institut National de la Santé et de la Recherche Medicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Equipe labellisée Ligue contre le cancer, Hôpital St. Louis, 75475 Paris, France
| | - Alexandre Gay
- University Paris Diderot, Sorbonne Paris Cité, Pathologie et Virologie Moléculaire, Institut National de la Santé et de la Recherche Medicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Equipe labellisée Ligue contre le cancer, Hôpital St. Louis, 75475 Paris, France
| | - Sergine Brutus
- University Paris Diderot, Sorbonne Paris Cité, Pathologie et Virologie Moléculaire, Institut National de la Santé et de la Recherche Medicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Equipe labellisée Ligue contre le cancer, Hôpital St. Louis, 75475 Paris, France
| | - Frédéric Jourquin
- Aix-Marseille University, CNRS UMR 7258, INSERM UMR1068, Institut Paoli-Calmettes, Cancer Research Center of Marseille, Equipe labellisée Ligue contre le cancer, 13273 Marseille, France
| | - Shweta Mendiratta
- University Paris Diderot, Sorbonne Paris Cité, Pathologie et Virologie Moléculaire, Institut National de la Santé et de la Recherche Medicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Equipe labellisée Ligue contre le cancer, Hôpital St. Louis, 75475 Paris, France
| | - Jean Salamero
- Institut Curie, PSL Research University, CNRS UMR 144, Pierre-and-Marie-Curie Université, Team-Space time imaging of endomembranes and organelles dynamics and PICT-IBiSA Imaging Core Facility, 75005 Paris, France
| | - Vincent Géli
- Aix-Marseille University, CNRS UMR 7258, INSERM UMR1068, Institut Paoli-Calmettes, Cancer Research Center of Marseille, Equipe labellisée Ligue contre le cancer, 13273 Marseille, France
| | - Catherine Dargemont
- University Paris Diderot, Sorbonne Paris Cité, Pathologie et Virologie Moléculaire, Institut National de la Santé et de la Recherche Medicale (INSERM), Centre National de la Recherche Scientifique (CNRS), Equipe labellisée Ligue contre le cancer, Hôpital St. Louis, 75475 Paris, France
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20
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Spichal M, Brion A, Herbert S, Cournac A, Marbouty M, Zimmer C, Koszul R, Fabre E. Evidence for a dual role of actin in regulating chromosome organization and dynamics in yeast. J Cell Sci 2016; 129:681-92. [PMID: 26763908 DOI: 10.1242/jcs.175745] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 01/05/2016] [Indexed: 01/07/2023] Open
Abstract
Eukaryotic chromosomes undergo movements that are involved in the regulation of functional processes such as DNA repair. To better understand the origin of these movements, we used fluorescence microscopy, image analysis and chromosome conformation capture to quantify the actin contribution to chromosome movements and interactions in budding yeast. We show that both the cytoskeletal and nuclear actin drive local chromosome movements, independently of Csm4, a putative LINC protein. Inhibition of actin polymerization reduces subtelomere dynamics, resulting in more confined territories and enrichment in subtelomeric contacts. Artificial tethering of actin to nuclear pores increased both nuclear pore complex (NPC) and subtelomere motion. Chromosome loci that were positioned away from telomeres exhibited reduced motion in the presence of an actin polymerization inhibitor but were unaffected by the lack of Csm4. We further show that actin was required for locus mobility that was induced by targeting the chromatin-remodeling protein Ino80. Correlated with this, DNA repair by homologous recombination was less efficient. Overall, interphase chromosome dynamics are modulated by the additive effects of cytoskeletal actin through forces mediated by the nuclear envelope and nuclear actin, probably through the function of actin in chromatin-remodeling complexes.
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Affiliation(s)
- Maya Spichal
- INSERM UMR 944, Equipe Biologie et Dynamique des Chromosomes, Institut Universitaire d'Hématologie, Hôpital St. Louis 1, Avenue Claude Vellefaux, Paris 75010, France CNRS, UMR 7212, Paris 75010, France Université Paris Diderot, Sorbonne Paris Cité, Paris 75010, France Institut Pasteur, Groupe Régulation Spatiale des Génomes, Paris 75015, France CNRS, UMR 3525, Paris 75015, France Sorbonne Universités, UPMC Université Paris 6, Paris 75005, France
| | - Alice Brion
- INSERM UMR 944, Equipe Biologie et Dynamique des Chromosomes, Institut Universitaire d'Hématologie, Hôpital St. Louis 1, Avenue Claude Vellefaux, Paris 75010, France CNRS, UMR 7212, Paris 75010, France Université Paris Diderot, Sorbonne Paris Cité, Paris 75010, France
| | - Sébastien Herbert
- Institut Pasteur, Unité Imagerie et Modélisation, Paris 75015, France CNRS, URA 2582, Paris 75015, France
| | - Axel Cournac
- Institut Pasteur, Groupe Régulation Spatiale des Génomes, Paris 75015, France CNRS, UMR 3525, Paris 75015, France
| | - Martial Marbouty
- Institut Pasteur, Groupe Régulation Spatiale des Génomes, Paris 75015, France CNRS, UMR 3525, Paris 75015, France
| | - Christophe Zimmer
- Institut Pasteur, Unité Imagerie et Modélisation, Paris 75015, France CNRS, URA 2582, Paris 75015, France
| | - Romain Koszul
- Institut Pasteur, Groupe Régulation Spatiale des Génomes, Paris 75015, France CNRS, UMR 3525, Paris 75015, France
| | - Emmanuelle Fabre
- INSERM UMR 944, Equipe Biologie et Dynamique des Chromosomes, Institut Universitaire d'Hématologie, Hôpital St. Louis 1, Avenue Claude Vellefaux, Paris 75010, France CNRS, UMR 7212, Paris 75010, France Université Paris Diderot, Sorbonne Paris Cité, Paris 75010, France Institut Pasteur, Groupe Régulation Spatiale des Génomes, Paris 75015, France CNRS, UMR 3525, Paris 75015, France
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21
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Guet D, Burns LT, Maji S, Boulanger J, Hersen P, Wente SR, Salamero J, Dargemont C. Combining Spinach-tagged RNA and gene localization to image gene expression in live yeast. Nat Commun 2015; 6:8882. [PMID: 26582123 PMCID: PMC4673486 DOI: 10.1038/ncomms9882] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 10/13/2015] [Indexed: 11/14/2022] Open
Abstract
Although many factors required for the formation of export-competent mRNPs have been described, an integrative view of the spatiotemporal coordinated cascade leading mRNPs from their site of transcription to their site of nuclear exit, at a single cell level, is still partially missing due to technological limitations. Here we report that the RNA Spinach aptamer is a powerful tool for mRNA imaging in live S. cerevisiae with high spatial-temporal resolution and no perturbation of the mRNA biogenesis properties. Dedicated image processing workflows are developed to allow detection of very low abundance of transcripts, accurate quantitative dynamic studies, as well as to provide a localization precision close to 100 nm at consistent time scales. Combining these approaches has provided a state-of-the-art analysis of the osmotic shock response in live yeast by localizing induced transcription factors, target gene loci and corresponding transcripts. Measuring single-cell mRNA dynamics is critical to understand gene expression. Here, using RNA Spinach technique to detect very low abundant mRNAs, Guet et al. report an analysis of the osmotic shock response in live yeast by localizing induced transcription factors, target gene loci and corresponding transcripts.
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Affiliation(s)
- David Guet
- Univ Paris Diderot, Sorbonne Paris Cité, INSERM UMR944, CNRS UMR7212, Equipe labellisée Ligue contre le cancer, Hôpital St Louis, 1 Avenue Claude Vellefaux, 75475 Paris Cedex 10, 75475, France
| | - Laura T Burns
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, 205 Kirkland Hall, Nashville, Tennessee 37232-8240, USA
| | - Suman Maji
- Univ Paris Diderot, Sorbonne Paris Cité, INSERM UMR944, CNRS UMR7212, Equipe labellisée Ligue contre le cancer, Hôpital St Louis, 1 Avenue Claude Vellefaux, 75475 Paris Cedex 10, 75475, France
| | - Jérôme Boulanger
- Team-Space Time Imaging of Endomembranes and Organelles Dynamics, UMR144 CNRS, Univ Pierre et Marie Curie, Institut Curie, 12 rue Lhomond, Paris 75005, France
| | - Pascal Hersen
- Univ Paris Diderot, Sorbonne Paris Cité, CNRS UMR7057, Laboratoire Matière et Systèmes Complexes, 10 rue Alice Domon et Léonie Duquet, Paris 75013, France
| | - Susan R Wente
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, 205 Kirkland Hall, Nashville, Tennessee 37232-8240, USA
| | - Jean Salamero
- Team-Space Time Imaging of Endomembranes and Organelles Dynamics, UMR144 CNRS, Univ Pierre et Marie Curie, Institut Curie, 12 rue Lhomond, Paris 75005, France.,PICT-IBiSA Imaging Core Facility, Institut Curie, 12 rue Lhomond, Paris 75005, France
| | - Catherine Dargemont
- Univ Paris Diderot, Sorbonne Paris Cité, INSERM UMR944, CNRS UMR7212, Equipe labellisée Ligue contre le cancer, Hôpital St Louis, 1 Avenue Claude Vellefaux, 75475 Paris Cedex 10, 75475, France
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22
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Webster BM, Colombi P, Jäger J, Lusk CP. Surveillance of nuclear pore complex assembly by ESCRT-III/Vps4. Cell 2015; 159:388-401. [PMID: 25303532 DOI: 10.1016/j.cell.2014.09.012] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 07/07/2014] [Accepted: 09/04/2014] [Indexed: 12/19/2022]
Abstract
The maintenance of nuclear compartmentalization by the nuclear envelope and nuclear pore complexes (NPCs) is essential for cell function; loss of compartmentalization is associated with cancers, laminopathies, and aging. We uncovered a pathway that surveils NPC assembly intermediates to promote the formation of functional NPCs. Surveillance is mediated by Heh2, a member of the LEM (Lap2-emerin-MAN1) family of integral inner nuclear membrane proteins, which binds to an early NPC assembly intermediate, but not to mature NPCs. Heh2 recruits the endosomal sorting complex required for transport (ESCRT)-III subunit Snf7 and the AAA-ATPase Vps4 to destabilize and clear defective NPC assembly intermediates. When surveillance or clearance is compromised, malformed NPCs accumulate in a storage of improperly assembled nuclear pore complexes compartment, or SINC. The SINC is retained in old mothers to prevent loss of daughter lifespan, highlighting a continuum of mechanisms to ensure nuclear compartmentalization.
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Affiliation(s)
- Brant M Webster
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Paolo Colombi
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Jens Jäger
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520, USA
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520, USA.
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23
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Tran EJ, King MC, Corbett AH. Macromolecular transport between the nucleus and the cytoplasm: Advances in mechanism and emerging links to disease. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1843:2784-2795. [PMID: 25116306 PMCID: PMC4161953 DOI: 10.1016/j.bbamcr.2014.08.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/01/2014] [Accepted: 08/02/2014] [Indexed: 01/08/2023]
Abstract
Transport of macromolecules between the cytoplasm and the nucleus is critical for the function of all eukaryotic cells. Large macromolecular channels termed nuclear pore complexes that span the nuclear envelope mediate the bidirectional transport of cargoes between the nucleus and cytoplasm. However, the influence of macromolecular trafficking extends past the nuclear pore complex to transcription and RNA processing within the nucleus and signaling pathways that reach into the cytoplasm and beyond. At the Mechanisms of Nuclear Transport biennial meeting held from October 18 to 23, 2013 in Woods Hole, MA, researchers in the field met to report on their recent findings. The work presented highlighted significant advances in understanding nucleocytoplasmic trafficking including how transport receptors and cargoes pass through the nuclear pore complex, the many signaling pathways that impinge on transport pathways, interplay between the nuclear envelope, nuclear pore complexes, and transport pathways, and numerous links between transport pathways and human disease. The goal of this review is to highlight newly emerging themes in nuclear transport and underscore the major questions that are likely to be the focus of future research in the field.
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Affiliation(s)
- Elizabeth J Tran
- Department of Biochemistry, Purdue University, 175 S. University Street, West Lafayette, IN 47907, USA; Purdue University Center for Cancer Research, Purdue University, Hansen Life Sciences Research Building, Room 141, 201 S. University Street, West Lafayette, IN 47907, USA.
| | - Megan C King
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Anita H Corbett
- Department of Biochemistry, Emory University School of Medicine, 4117 Rollins Research Center, 1510 Clifton Road, NE, Atlanta, GA 30322, USA.
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24
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Niño CA, Hayakawa A, Dargemont C, Babour A. Mapping ubiquitin modifications reveals new functions for the yeast nuclear pore complex. CELLULAR LOGISTICS 2014; 2:43-45. [PMID: 22645709 PMCID: PMC3355974 DOI: 10.4161/cl.19720] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Covalent attachment of ubiquitin to target proteins, or ubiquitylation, has emerged as one of the most prevalent posttranslational modifications (PTMs), regulating nearly every cellular pathway. The diversity of functions associated with this particular PTM stems from the myriad ways in which a target protein can be modified by ubiquitin, e.g., monoubiquitin, multi-monoubiquitin and polyubiquitin linkages. In the current study, we took a systematic approach to analyze the ubiquitylation profiles of the yeast Saccharomyces cerevisiae nuclear pore complex (NPC) proteins or nucleoporins. We found the yeast NPC to be extensively modified by ubiquitin with highly variable ubiquitylation profiles, suggesting that dissection of these modifications may provide new insights into the regulation of NPC functions and reveal additional roles for nucleoporins beyond nuclear transport.
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Affiliation(s)
- Carlos A Niño
- Institut Jacques Monod; University Paris Diderot; Sorbonne Paris Cité; CNRS UMR7592; Paris, France
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25
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Bonizec M, Hérissant L, Pokrzywa W, Geng F, Wenzel S, Howard GC, Rodriguez P, Krause S, Tansey WP, Hoppe T, Dargemont C. The ubiquitin-selective chaperone Cdc48/p97 associates with Ubx3 to modulate monoubiquitylation of histone H2B. Nucleic Acids Res 2014; 42:10975-86. [PMID: 25183520 PMCID: PMC4176170 DOI: 10.1093/nar/gku786] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/18/2014] [Accepted: 08/18/2014] [Indexed: 11/14/2022] Open
Abstract
Cdc48/p97 is an evolutionary conserved ubiquitin-dependent chaperone involved in a broad array of cellular functions due to its ability to associate with multiple cofactors. Aside from its role in removing RNA polymerase II from chromatin after DNA damage, little is known about how this AAA-ATPase is involved in the transcriptional process. Here, we show that yeast Cdc48 is recruited to chromatin in a transcription-coupled manner and modulates gene expression. Cdc48, together with its cofactor Ubx3 controls monoubiquitylation of histone H2B, a conserved modification regulating nucleosome dynamics and chromatin organization. Mechanistically, Cdc48 facilitates the recruitment of Lge1, a cofactor of the H2B ubiquitin ligase Bre1. The function of Cdc48 in controlling H2B ubiquitylation appears conserved in human cells because disease-related mutations or chemical inhibition of p97 function affected the amount of ubiquitylated H2B in muscle cells. Together, these results suggest a prominent role of Cdc48/p97 in the coordination of chromatin remodeling with gene transcription to define cellular differentiation processes.
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Affiliation(s)
- Mélanie Bonizec
- Sorbonne Paris Cité, INSERM UMR944, CNRS UMR7212, Equipe labellisée Ligue contre le cancer, University of Paris Diderot, Hôpital St. Louis 1, Avenue Claude Vellefaux 75475 Paris Cedex 10, France
| | - Lucas Hérissant
- Sorbonne Paris Cité, INSERM UMR944, CNRS UMR7212, Equipe labellisée Ligue contre le cancer, University of Paris Diderot, Hôpital St. Louis 1, Avenue Claude Vellefaux 75475 Paris Cedex 10, France
| | - Wojciech Pokrzywa
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Fuqiang Geng
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, 465 21st Avenue South, Nashville, TN 37232, USA
| | - Sabine Wenzel
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, 465 21st Avenue South, Nashville, TN 37232, USA
| | - Gregory C Howard
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, 465 21st Avenue South, Nashville, TN 37232, USA
| | - Paco Rodriguez
- Sorbonne Paris Cité, INSERM UMR944, CNRS UMR7212, Equipe labellisée Ligue contre le cancer, University of Paris Diderot, Hôpital St. Louis 1, Avenue Claude Vellefaux 75475 Paris Cedex 10, France
| | - Sabine Krause
- Laboratory for Molecular Myology, Friedrich Baur Institute, Department of Neurology, Ludwig Maximilians University, Munich, Germany
| | - William P Tansey
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, 465 21st Avenue South, Nashville, TN 37232, USA
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Catherine Dargemont
- Sorbonne Paris Cité, INSERM UMR944, CNRS UMR7212, Equipe labellisée Ligue contre le cancer, University of Paris Diderot, Hôpital St. Louis 1, Avenue Claude Vellefaux 75475 Paris Cedex 10, France
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26
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Bonnet A, Palancade B. Regulation of mRNA trafficking by nuclear pore complexes. Genes (Basel) 2014; 5:767-91. [PMID: 25184662 PMCID: PMC4198930 DOI: 10.3390/genes5030767] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 11/17/2022] Open
Abstract
Over the last two decades, multiple studies have explored the mechanisms governing mRNA export out of the nucleus, a crucial step in eukaryotic gene expression. During transcription and processing, mRNAs are assembled into messenger ribonucleoparticles (mRNPs). mRNPs are then exported through nuclear pore complexes (NPCs), which are large multiprotein assemblies made of several copies of a limited number of nucleoporins. A considerable effort has been put into the dissection of mRNA export through NPCs at both cellular and molecular levels, revealing the conserved contributions of a subset of nucleoporins in this process, from yeast to vertebrates. Several reports have also demonstrated the ability of NPCs to sort out properly-processed mRNPs for entry into the nuclear export pathway. Importantly, changes in mRNA export have been associated with post-translational modifications of nucleoporins or changes in NPC composition, depending on cell cycle progression, development or exposure to stress. How NPC modifications also impact on cellular mRNA export in disease situations, notably upon viral infection, is discussed.
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Affiliation(s)
- Amandine Bonnet
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, Paris F-75205, France.
| | - Benoit Palancade
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité, Paris F-75205, France.
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27
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Beck M, Glavy JS. Toward understanding the structure of the vertebrate nuclear pore complex. Nucleus 2014; 5:119-23. [PMID: 24699243 DOI: 10.4161/nucl.28739] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Nuclear pore complexes are large macromolecular assemblies that facilitate the nucleocytoplasmic exchange of macromolecules. Because of their intricate composition, membrane association, and sheer size, the integration of various, complementary structure determination approaches is a prerequisite for elucidating their structure. We have recently employed such an integrated strategy to analyze the scaffold structure of the cytoplasmic and nuclear rings of the human nuclear pore complex. In this extra view, we highlight two specific aspects of this work: the power of electron microscopy for bridging different resolution regimes and the importance of post-translational modifications for regulating nucleoporin interactions. We review recent technological developments and give a perspective toward future structure determination approaches.
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Affiliation(s)
- Martin Beck
- European Molecular Biology Laboratory; Structural and Computational Biology Unit; Heidelberg, Germany; Stevens Institute of Technology; Department of Chemistry, Chemical Biology, and Biomedical Engineering; Hoboken, NJ USA
| | - Joseph S Glavy
- European Molecular Biology Laboratory; Structural and Computational Biology Unit; Heidelberg, Germany; Stevens Institute of Technology; Department of Chemistry, Chemical Biology, and Biomedical Engineering; Hoboken, NJ USA
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28
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Ptak C, Aitchison JD, Wozniak RW. The multifunctional nuclear pore complex: a platform for controlling gene expression. Curr Opin Cell Biol 2014; 28:46-53. [PMID: 24657998 DOI: 10.1016/j.ceb.2014.02.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 02/21/2014] [Accepted: 02/22/2014] [Indexed: 12/21/2022]
Abstract
In addition to their established roles in nucleocytoplasmic transport, the intimate association of nuclear pore complexes (NPCs) with chromatin has long led to speculation that these structures influence peripheral chromatin structure and regulate gene expression. These ideas have their roots in morphological observations, however recent years have seen the identification of physical interactions between NPCs, chromatin, and the transcriptional machinery. Key insights into the molecular functions of specific NPC proteins have uncovered roles for these proteins in transcriptional activation and elongation, mRNA processing, as well as chromatin structure and localization. Here, we review recent studies that provide further molecular detail on the role of specific NPC components as distinct platforms for these chromatin dependent processes.
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Affiliation(s)
- Christopher Ptak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - John D Aitchison
- Seattle Biomedical Research Institute and Institute for Systems Biology, 307 Westlake Ave N, Seattle, WA 98109, USA.
| | - Richard W Wozniak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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29
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Ossareh-Nazari B, Niño CA, Bengtson MH, Lee JW, Joazeiro CAP, Dargemont C. Ubiquitylation by the Ltn1 E3 ligase protects 60S ribosomes from starvation-induced selective autophagy. ACTA ACUST UNITED AC 2014; 204:909-17. [PMID: 24616224 PMCID: PMC3998797 DOI: 10.1083/jcb.201308139] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The E3 ligase Ltn1 and the deubiquitylase Ubp3-Bre5 titrate the level of ribosomal subunit ubiquitylation and thereby set the rate of ribosomal protein degradation by ribophagy in response to nutrient supply and the level of protein translation. Autophagy, the process by which proteins or organelles are engulfed by autophagosomes and delivered for vacuolar/lysosomal degradation, is induced to ensure survival under starvation and other stresses. A selective autophagic pathway for 60S ribosomal subunits elicited by nitrogen starvation in yeast—ribophagy—was recently described and requires the Ubp3-Bre5 deubiquitylating enzyme. This discovery implied that an E3 ligases act upstream, whether inhibiting the process or providing an initial required signal. In this paper, we show that Ltn1/Rkr1, a 60S ribosome-associated E3 implicated in translational surveillance, acts as an inhibitor of 60S ribosomal subunit ribophagy and is antagonized by Ubp3. The ribosomal protein Rpl25 is a relevant target. Its ubiquitylation is Ltn1 dependent and Ubp3 reversed, and mutation of its ubiquitylation site rendered ribophagy less dependent on Ubp3. Consistently, the expression of Ltn1—but not Ubp3—rapidly decreased after starvation, presumably to allow ribophagy to proceed. Thus, Ltn1 and Ubp3-Bre5 likely contribute to adapt ribophagy activity to both nutrient supply and protein translation.
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Affiliation(s)
- Batool Ossareh-Nazari
- Institut Jacques Monod, University Paris Diderot, Sorbonne Paris Cité, and Centre National de la Recherche Scientifique Unité Mixte de Recherche 7592, 75205 Paris, Cedex 13, France
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30
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Floch AG, Palancade B, Doye V. Fifty years of nuclear pores and nucleocytoplasmic transport studies: multiple tools revealing complex rules. Methods Cell Biol 2014; 122:1-40. [PMID: 24857723 DOI: 10.1016/b978-0-12-417160-2.00001-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nuclear pore complexes (NPCs) are multiprotein assemblies embedded within the nuclear envelope and involved in the control of the bidirectional transport of proteins and ribonucleoparticles between the nucleus and the cytoplasm. Since their discovery more than 50 years ago, NPCs and nucleocytoplasmic transport have been the focus of intense research. Here, we review how the use of a multiplicity of structural, biochemical, genetic, and cell biology approaches have permitted the deciphering of the main features of this macromolecular complex, its mode of assembly as well as the rules governing nucleocytoplasmic exchanges. We first present the current knowledge of the ultrastructure of NPCs, which reveals that they are modular and repetitive assemblies of subunits referred to as nucleoporins, associated into stable subcomplexes and composed of a limited set of protein domains, including phenylalanine-glycine (FG) repeats and membrane-interacting domains. The outcome of investigations on nucleocytoplasmic trafficking will then be detailed, showing how it involves a limited number of molecular factors and common mechanisms, namely (i) indirect association of cargos with nuclear pores through receptors in the donor compartment, (ii) progression within the channel through dynamic hydrophobic interactions with FG-Nups, and (iii) NTPase-driven remodeling of transport complexes in the target compartment. Finally, we also discuss the outcome of more recent studies, which indicate that NPCs and the transport machinery are dynamic and versatile devices, whose biogenesis is tightly coordinated with the cell cycle, and which carry nonconventional duties, in particular, in mitosis, gene expression, and genetic stability.
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Affiliation(s)
- Aurélie G Floch
- Institut Jacques Monod, CNRS, UMR 7592, Univ. Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France; Ecole Doctorale Gènes Génomes Cellules, Université Paris Sud-11, Orsay, France
| | - Benoit Palancade
- Institut Jacques Monod, CNRS, UMR 7592, Univ. Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France
| | - Valérie Doye
- Institut Jacques Monod, CNRS, UMR 7592, Univ. Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France
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31
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Colombi P, Webster BM, Fröhlich F, Lusk CP. The transmission of nuclear pore complexes to daughter cells requires a cytoplasmic pool of Nsp1. ACTA ACUST UNITED AC 2013; 203:215-32. [PMID: 24165936 PMCID: PMC3812967 DOI: 10.1083/jcb.201305115] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nuclear pore complexes (NPCs) are essential protein assemblies that span the nuclear envelope and establish nuclear-cytoplasmic compartmentalization. We have investigated mechanisms that control NPC number in mother and daughter cells during the asymmetric division of budding yeast. By simultaneously tracking existing NPCs and newly synthesized NPC protomers (nups) through anaphase, we uncovered a pool of the central channel nup Nsp1 that is actively targeted to the bud in association with endoplasmic reticulum. Bud targeting required an intact actin cytoskeleton and the class V myosin, Myo2. Selective inhibition of cytoplasmic Nsp1 or inactivation of Myo2 reduced the inheritance of NPCs in daughter cells, leading to a daughter-specific loss of viability. Our data are consistent with a model in which Nsp1 releases a barrier that otherwise prevents NPC passage through the bud neck. It further supports the finding that NPC inheritance, not de novo NPC assembly, is primarily responsible for controlling NPC number in daughter cells.
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Affiliation(s)
- Paolo Colombi
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
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32
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Meadows JC, Graumann K, Platani M, Schweizer N, Shimi T, Vagnarelli P, Gatlin JC. Meeting report: mitosis and nuclear structure. J Cell Sci 2013; 126:5087-90. [PMID: 24244037 DOI: 10.1242/jcs.142950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Company of Biologists Workshop entitled 'Mitosis and Nuclear Structure' was held at Wiston House, West Sussex in June 2013. It provided a unique and timely opportunity for leading experts from different fields to discuss not only their own work but also its broader context. Here we present the proceedings of this meeting and several major themes that emerged from the crosstalk between the two, as it turns out, not so disparate fields of mitosis and nuclear structure. Co-chaired by Katherine Wilson (Johns Hopkins School of Medicine, Baltimore, MD), Timothy Mitchison (Harvard University, Cambridge, MA) and Michael Rout (Rockefeller University, New York, NY), this workshop brought together a small group of scientists from a range of disciplines to discuss recent advances and connections between the areas of mitosis and nuclear structure research. Several early-career researchers (students, postdoctoral researchers, junior faculty) participated along with 20 senior scientists, including the venerable and affable Nobel Laureate Tim Hunt. Participants were encouraged to embrace unconventional thinking in the 'scientific sandbox' created by this unusual combination of researchers in the inspiring, isolated setting of the 16th-century Wiston House.
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Affiliation(s)
- John C Meadows
- Division of Biomedical Cell Biology, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
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33
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Dynein Light Chain 1 (DYNLT1) Interacts with Normal and Oncogenic Nucleoporins. PLoS One 2013; 8:e67032. [PMID: 23840580 PMCID: PMC3694108 DOI: 10.1371/journal.pone.0067032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 05/13/2013] [Indexed: 12/18/2022] Open
Abstract
The chimeric oncoprotein NUP98-HOXA9 results from the t(7;11)(p15;p15) chromosomal translocation and is associated with acute myeloid leukemia. It causes aberrant gene regulation and leukemic transformation through mechanisms that are not fully understood. NUP98-HOXA9 consists of an N-terminal portion of the nucleoporin NUP98 that contains many FG repeats fused to the DNA-binding homeodomain of HOXA9. We used a Cytotrap yeast two-hybrid assay to identify proteins that interact with NUP98-HOXA9. We identified Dynein Light Chain 1 (DYNLT1), an integral 14 KDa protein subunit of the large microtubule-based cytoplasmic dynein complex, as an interaction partner of NUP98-HOXA9. Binding was confirmed by in vitro pull down and co-immunoprecipitation assays and the FG repeat region of NUP98-HOXA9 was shown to be essential for the interaction. RNAi-mediated knockdown of DYNLT1 resulted in reduction of the ability of NUP98-HOXA9 to activate transcription and also inhibited the ability of NUP98-HOXA9 to induce proliferation of primary human hematopoietic CD34+ cells. DYNLT1 also showed a strong interaction with wild-type NUP98 and other nucleoporins containing FG repeats. Immunofluorescence analysis showed that DYNLT1 localizes primarily to the nuclear periphery, where it co-localizes with the nuclear pore complex, and to the cytoplasm. Deletion studies showed that the interactions of the nucleoporins with DYNLT1 are dependent predominantly on the C-terminal half of the DYNLT1. These data show for the first time that DYNLT1 interacts with nucleoporins and plays a role in the dysregulation of gene expression and induction of hematopoietic cell proliferation by the leukemogenic nucleoporin fusion, NUP98-HOXA9.
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Affiliation(s)
- C A Niño
- Institut Jacques Monod, Paris Diderot University , Sorbonne Paris Cité, CNRS UMR7592, Equipe labellisée Ligue contre le cancer, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
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35
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Abstract
In fungi, nuclear pore complexes are free to move through the nuclear envelope; however, little is known about how movement is regulated. New evidence reveals roles for molecular motors and potential impacts on genomic organization.
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Affiliation(s)
- Amanda K Casey
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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36
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Abstract
Advances in imaging and reductionist approaches have provided a high-resolution understanding of nuclear pore complex structure and transport, revealing unexpected mechanistic complexities based on nucleoporin functions and specialized import and export pathways.
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37
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Nyarko A, Song Y, Nováček J, Žídek L, Barbar E. Multiple recognition motifs in nucleoporin Nup159 provide a stable and rigid Nup159-Dyn2 assembly. J Biol Chem 2012; 288:2614-22. [PMID: 23223634 DOI: 10.1074/jbc.m112.432831] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dyn2 is the yeast ortholog of the molecular hub LC8, which binds disordered proteins and promotes their self-association and higher order assembly. Dyn2 is proposed to dimerize and stabilize the Nup82-Nsp1-Nup159 complex of the nuclear pore assembly through its interaction with nucleoporin Nup159. Nup159 has six LC8 recognition motifs separated by short linkers. NMR experiments reported here show that the Dyn2 binding domain of Nup159 is intrinsically disordered and that binding of one equivalent of Dyn2 dimer aligns two Nup159 chains along the full Dyn2 binding domain to form a bivalent scaffold that promotes binding of other Dyn2 dimers. Isothermal titration calorimetry of Dyn2 binding to Nup constructs of increasing lengths determine that the third LC8 recognition motifs does not bind Dyn2. A new approach to identifying active LC8 recognition motifs based on NMR-detected β-sheet propensities is presented. Isothermal titration calorimetry experiments also show that, due to unfavorable entropy changes, a Nup-Dyn2 complex with three Dyn2 dimers is more stable than the wild-type complex with five Dyn2 dimers. The calorimetric results argue that, from a thermodynamics perspective, only three Dyn2 dimers are needed for optimal stability and suggest that the evolutionary adaptation of multiple tandem LC8 recognition motifs imparts to the complex other properties such as rigidity and a kink in the rod-like structure. These findings extend the repertoire of functions of intrinsically disordered protein to fine-tuning and versatile assembly of higher order macromolecular complexes.
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Affiliation(s)
- Afua Nyarko
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA
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39
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Short B. Ubiquitylation keeps the nucleus moving. J Biophys Biochem Cytol 2012. [PMCID: PMC3255980 DOI: 10.1083/jcb.1961iti1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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40
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Babour A, Dargemont C, Stutz F. Ubiquitin and assembly of export competent mRNP. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:521-30. [PMID: 22240387 DOI: 10.1016/j.bbagrm.2011.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 12/20/2011] [Accepted: 12/22/2011] [Indexed: 11/24/2022]
Abstract
The production of mature and export competent mRNP (mRNA ribonucleoprotein) complexes depends on a series of highly coordinated processing reactions. RNA polymerase II (RNAPII) plays a central role in this process by mediating the sequential recruitment of mRNA maturation and export factors to transcribing genes, thereby establishing a strong functional link between transcription and export through nuclear pore complexes (NPC). Growing evidence indicates that post-translational modifications participate in the dynamic association of processing and export factors with mRNAs ensuring that the transitions and rearrangements undergone by the mRNP occur at the right time and place. This review mainly focuses on the role of ubiquitin conjugation in controlling mRNP assembly and quality control from transcription down to export through the NPC. It emphasizes the central role of ubiquitylation in organizing the chronology of events along this highly dynamic pathway. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing.
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Affiliation(s)
- Anna Babour
- Institut Jacques Monod, Université Paris Diderot, CNRS, Bâtiment Buffon, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
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