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Guo Y, Tao T, Wu T, Hou J, Lin W. Nucleoporin Nup98 is an essential factor for ipo4 dependent protein import. J Cell Biochem 2024. [PMID: 38780165 DOI: 10.1002/jcb.30573] [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: 11/16/2023] [Revised: 04/12/2024] [Accepted: 04/19/2024] [Indexed: 05/25/2024]
Abstract
Nucleocytoplasmic transport of macromolecules is essential in eukaryotic cells. In this process, the karyopherins play a central role when they transport cargoes across the nuclear pore complex. Importin 4 belongs to the karyopherin β family. Many studies have focused on finding substrates for importin 4, but no direct mechanism studies of its precise transport function have been reported. Therefore, this paper mainly aimed to study the mechanism of nucleoporins in mediating nuclear import and export of importin 4. To address this question, we constructed shRNAs targeting Nup358, Nup153, Nup98, and Nup50. We found that depletion of Nup98 resulted in a shift in the subcellular localization of importin 4 from the cytoplasm to the nucleus. Mutational analysis demonstrated that Nup98 physically and functionally interacts with importin 4 through its N-terminal phenylalanine-glycine (FG) repeat region. Mutation of nine of these FG motifs to SG motifs significantly attenuated the binding of Nup98 to importin 4, and we further confirmed the essential role of the six FG motifs in amino acids 121-360 of Nup98 in binding with importin 4. In vitro transport assay also confirmed that VDR, the substrate of importin 4, could not be transported into the nucleus after Nup98 knockdown. Overall, our results showed that Nup98 is required for efficient importin 4-mediated transport. This is the first study to reveal the mechanism of importin 4 in transporting substrates into the nucleus.
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Affiliation(s)
- Yingying Guo
- State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiame, Fujian, China
| | - Tao Tao
- State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiame, Fujian, China
| | - Ting Wu
- Department of Basic Medicine, School of Medicine, Cancer Research Center, Xiamen University, Xiamen, Fujian, China
| | - Jingjing Hou
- State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiame, Fujian, China
- Department of Gastrointestinal Surgery, School of Medicine, Zhongshan Hospital of Xiamen University, Xiamen University, Xiamen, Fujian, China
| | - Wenbo Lin
- State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiame, Fujian, China
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2
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Oka M, Otani M, Miyamoto Y, Oshima R, Adachi J, Tomonaga T, Asally M, Nagaoka Y, Tanaka K, Toyoda A, Ichikawa K, Morishita S, Isono K, Koseki H, Nakato R, Ohkawa Y, Yoneda Y. Phase-separated nuclear bodies of nucleoporin fusions promote condensation of MLL1/CRM1 and rearrangement of 3D genome structure. Cell Rep 2023; 42:112884. [PMID: 37516964 DOI: 10.1016/j.celrep.2023.112884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/29/2023] [Accepted: 07/13/2023] [Indexed: 08/01/2023] Open
Abstract
NUP98 and NUP214 form chimeric fusion proteins that assemble into phase-separated nuclear bodies containing CRM1, a nuclear export receptor. However, these nuclear bodies' function in controlling gene expression remains elusive. Here, we demonstrate that the nuclear bodies of NUP98::HOXA9 and SET::NUP214 promote the condensation of mixed lineage leukemia 1 (MLL1), a histone methyltransferase essential for the maintenance of HOX gene expression. These nuclear bodies are robustly associated with MLL1/CRM1 and co-localized on chromatin. Furthermore, whole-genome chromatin-conformation capture analysis reveals that NUP98::HOXA9 induces a drastic alteration in high-order genome structure at target regions concomitant with the generation of chromatin loops and/or rearrangement of topologically associating domains in a phase-separation-dependent manner. Collectively, these results show that the phase-separated nuclear bodies of nucleoporin fusion proteins can enhance the activation of target genes by promoting the condensation of MLL1/CRM1 and rearrangement of the 3D genome structure.
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Affiliation(s)
- Masahiro Oka
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan; Laboratory of Biomedical Innovation, Graduate School of Pharmaceutical Sciences, Osaka University, 1-3 Yamada-oka, Suita, Osaka 565-0871, Japan.
| | - Mayumi Otani
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan
| | - Yoichi Miyamoto
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan
| | - Rieko Oshima
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan
| | - Jun Adachi
- Laboratory of Proteomics for Drug Discovery, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan
| | - Takeshi Tomonaga
- Laboratory of Proteomics for Drug Discovery, National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan
| | - Munehiro Asally
- School of Life Sciences, The University of Warwick, Coventry CV4 7AL, UK
| | - Yuya Nagaoka
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Kaori Tanaka
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
| | - Atsushi Toyoda
- Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Kazuki Ichikawa
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568, Japan
| | - Shinichi Morishita
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568, Japan
| | - Kyoichi Isono
- Laboratory Animal Center, Wakayama Medical University, 811-1 Kimi-idera, Wakayama 641-8509, Japan
| | - Haruhiko Koseki
- Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Ryuichiro Nakato
- Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
| | - Yasuyuki Ohkawa
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan.
| | - Yoshihiro Yoneda
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan
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3
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Neely AE, Blumensaadt LA, Ho PJ, Lloyd SM, Kweon J, Ren Z, Bao X. NUP98 and RAE1 sustain progenitor function through HDAC-dependent chromatin targeting to escape from nucleolar localization. Commun Biol 2023; 6:664. [PMID: 37353594 PMCID: PMC10290086 DOI: 10.1038/s42003-023-05043-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 06/13/2023] [Indexed: 06/25/2023] Open
Abstract
Self-renewing somatic tissues rely on progenitors to support the continuous tissue regeneration. The gene regulatory network maintaining progenitor function remains incompletely understood. Here we show that NUP98 and RAE1 are highly expressed in epidermal progenitors, forming a separate complex in the nucleoplasm. Reduction of NUP98 or RAE1 abolishes progenitors' regenerative capacity, inhibiting proliferation and inducing premature terminal differentiation. Mechanistically, NUP98 binds on chromatin near the transcription start sites of key epigenetic regulators (such as DNMT1, UHRF1 and EZH2) and sustains their expression in progenitors. NUP98's chromatin binding sites are co-occupied by HDAC1. HDAC inhibition diminishes NUP98's chromatin binding and dysregulates NUP98 and RAE1's target gene expression. Interestingly, HDAC inhibition further induces NUP98 and RAE1 to localize interdependently to the nucleolus. These findings identified a pathway in progenitor maintenance, where HDAC activity directs the high levels of NUP98 and RAE1 to directly control key epigenetic regulators, escaping from nucleolar aggregation.
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Affiliation(s)
- Amy E Neely
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Laura A Blumensaadt
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Patric J Ho
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Sarah M Lloyd
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Junghun Kweon
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Ziyou Ren
- Department of Dermatology, Northwestern University, Chicago, IL, USA
| | - Xiaomin Bao
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA.
- Department of Dermatology, Northwestern University, Chicago, IL, USA.
- Simpson Querrey Institute for Epigenetics, Northwestern University, Chicago, IL, USA.
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL, USA.
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4
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Komata Y, Kanai A, Maeda T, Inaba T, Yokoyama A. MOZ/ENL complex is a recruiting factor of leukemic AF10 fusion proteins. Nat Commun 2023; 14:1979. [PMID: 37031220 PMCID: PMC10082848 DOI: 10.1038/s41467-023-37712-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 03/22/2023] [Indexed: 04/10/2023] Open
Abstract
Changes in the transcriptional machinery cause aberrant self-renewal of non-stem hematopoietic progenitors. AF10 fusions, such as CALM-AF10, are generated via chromosomal translocations, causing malignant leukemia. In this study, we demonstrate that AF10 fusion proteins cause aberrant self-renewal via ENL, which binds to MOZ/MORF lysine acetyltransferases (KATs). The interaction of ENL with MOZ, via its YEATS domain, is critical for CALM-AF10-mediated leukemic transformation. The MOZ/ENL complex recruits DOT1L/AF10 fusion complexes and maintains their chromatin retention via KAT activity. Therefore, inhibitors of MOZ/MORF KATs directly suppress the functions of AF10 fusion proteins, thereby exhibiting strong antitumor effects on AF10 translocation-induced leukemia. Combinatorial inhibition of MOZ/MORF and DOT1L cooperatively induces differentiation of CALM-AF10-leukemia cells. These results reveal roles for the MOZ/ENL complex as an essential recruiting factor of the AF10 fusion/DOT1L complex, providing a rationale for using MOZ/MORF KAT inhibitors in AF10 translocation-induced leukemia.
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Affiliation(s)
- Yosuke Komata
- Tsuruoka Metabolomics Laboratory, National Cancer Center, Tsuruoka, Yamagata, 997-0052, Japan
| | - Akinori Kanai
- Laboratory of Systems Genomics, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, the University of Tokyo, Kashiwa, Chiba, 277-0882, Japan
- Department of Molecular Oncology and Leukemia Program Project, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Hiroshima, 734-8553, Japan
| | - Takahiro Maeda
- Division of Precision Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Fukuoka, 812-8582, Japan
| | - Toshiya Inaba
- Department of Molecular Oncology and Leukemia Program Project, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Hiroshima, 734-8553, Japan
| | - Akihiko Yokoyama
- Tsuruoka Metabolomics Laboratory, National Cancer Center, Tsuruoka, Yamagata, 997-0052, Japan.
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5
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Serganov AA, Udi Y, Stein ME, Patel V, Fridy PC, Rice CM, Saeed M, Jacobs EY, Chait BT, Rout MP. Proteomic elucidation of the targets and primary functions of the picornavirus 2A protease. J Biol Chem 2022; 298:101882. [PMID: 35367208 PMCID: PMC9168619 DOI: 10.1016/j.jbc.2022.101882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 03/04/2022] [Accepted: 03/06/2022] [Indexed: 11/19/2022] Open
Abstract
Picornaviruses are small RNA viruses that hijack host cell machinery to promote their replication. During infection, these viruses express two proteases, 2Apro and 3Cpro, which process viral proteins. They also subvert a number of host functions, including innate immune responses, host protein synthesis, and intracellular transport, by utilizing poorly understood mechanisms for rapidly and specifically targeting critical host proteins. Here, we used proteomic tools to characterize 2Apro interacting partners, functions, and targeting mechanisms. Our data indicate that, initially, 2Apro primarily targets just two cellular proteins: eukaryotic translation initiation factor eIF4G (a critical component of the protein synthesis machinery) and Nup98 (an essential component of the nuclear pore complex, responsible for nucleocytoplasmic transport). The protease appears to employ two different cleavage mechanisms; it likely interacts with eIF3L, utilizing the eIF3 complex to proteolytically access the eIF4G protein but also directly binds and degrades Nup98. This Nup98 cleavage results in only a marginal effect on nuclear import of proteins, while nuclear export of proteins and mRNAs were more strongly affected. Collectively, our data indicate that 2Apro selectively inhibits protein translation, key nuclear export pathways, and cellular mRNA localization early in infection to benefit viral replication at the expense of particular cell functions.
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Affiliation(s)
- Artem A Serganov
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, New York, USA
| | - Yael Udi
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, New York, USA.
| | - Milana E Stein
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, New York, USA
| | - Valay Patel
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, New York, USA
| | - Peter C Fridy
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, New York, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, New York, USA
| | - Mohsan Saeed
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, New York, USA; Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, USA; National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, Boston University, Massachusetts, USA.
| | - Erica Y Jacobs
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York, USA; Chemistry Department, St John's University, Queens, New York, USA.
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York, USA.
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, New York, USA.
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6
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The Retinoblastoma Tumor Suppressor Is Required for the NUP98-HOXA9-Induced Aberrant Nuclear Envelope Phenotype. Cells 2021; 10:cells10112851. [PMID: 34831074 PMCID: PMC8616146 DOI: 10.3390/cells10112851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022] Open
Abstract
Chromosomal translocations involving the nucleoporin NUP98 gene are recurrently identified in leukemia; yet, the cellular defects accompanying NUP98 fusion proteins are poorly characterized. NUP98 fusions cause changes in nuclear and nuclear envelope (NE) organization, in particular, in the nuclear lamina and the lamina associated polypeptide 2α (LAP2α), a regulator of the tumor suppressor retinoblastoma protein (RB). We demonstrate that, for NUP98-HOXA9 (NHA9), the best-studied NUP98 fusion protein, its effect(s) on nuclear architecture largely depend(s) on RB. Morphological alterations caused by the expression of NHA9 are largely diminished in the absence of RB, both in human cells expressing the human papillomavirus 16 E7 protein and in mouse embryonic fibroblasts lacking RB. We further show that NHA9 expression associates with distinct histone modification. Moreover, the pattern of trimethylation of histone H3 lysine-27 is affected by NHA9, again in an RB-dependent manner. Our results pinpoint to an unexpected interplay between NUP98 fusion proteins and RB, which may contribute to leukemogenesis.
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7
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Semmelink MFW, Steen A, Veenhoff LM. Measuring and Interpreting Nuclear Transport in Neurodegenerative Disease-The Example of C9orf72 ALS. Int J Mol Sci 2021; 22:9217. [PMID: 34502125 PMCID: PMC8431710 DOI: 10.3390/ijms22179217] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/13/2021] [Accepted: 08/18/2021] [Indexed: 11/25/2022] Open
Abstract
Transport from and into the nucleus is essential to all eukaryotic life and occurs through the nuclear pore complex (NPC). There are a multitude of data supporting a role for nuclear transport in neurodegenerative diseases, but actual transport assays in disease models have provided diverse outcomes. In this review, we summarize how nuclear transport works, which transport assays are available, and what matters complicate the interpretation of their results. Taking a specific type of ALS caused by mutations in C9orf72 as an example, we illustrate these complications, and discuss how the current data do not firmly answer whether the kinetics of nucleocytoplasmic transport are altered. Answering this open question has far-reaching implications, because a positive answer would imply that widespread mislocalization of proteins occurs, far beyond the reported mislocalization of transport reporters, and specific proteins such as FUS, or TDP43, and thus presents a challenge for future research.
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Affiliation(s)
| | | | - Liesbeth M. Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands; (M.F.W.S.); (A.S.)
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8
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Bensidoun P, Zenklusen D, Oeffinger M. Choosing the right exit: How functional plasticity of the nuclear pore drives selective and efficient mRNA export. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1660. [PMID: 33938148 DOI: 10.1002/wrna.1660] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/30/2021] [Accepted: 04/04/2021] [Indexed: 12/17/2022]
Abstract
The nuclear pore complex (NPC) serves as a central gate for mRNAs to transit from the nucleus to the cytoplasm. The ability for mRNAs to get exported is linked to various upstream nuclear processes including co-transcriptional RNP assembly and processing, and only export competent mRNPs are thought to get access to the NPC. While the nuclear pore is generally viewed as a monolithic structure that serves as a mediator of transport driven by transport receptors, more recent evidence suggests that the NPC might be more heterogenous than previously believed, both in its composition or in the selective treatment of cargo that seek access to the pore, providing functional plasticity to mRNA export. In this review, we consider the interconnected processes of nuclear mRNA metabolism that contribute and mediate export competence. Furthermore, we examine different aspects of NPC heterogeneity, including the role of the nuclear basket and its associated complexes in regulating selective and/or efficient binding to and transport through the pore. This article is categorized under: RNA Export and Localization > Nuclear Export/Import RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Pierre Bensidoun
- Systems Biology, Institut de Recherches Cliniques de Montréal, Montréal, Canada.,Département de Biochimie et Médecine Moléculaire, Faculté de médecine, Université de Montréal, Montréal, Canada
| | - Daniel Zenklusen
- Département de Biochimie et Médecine Moléculaire, Faculté de médecine, Université de Montréal, Montréal, Canada
| | - Marlene Oeffinger
- Systems Biology, Institut de Recherches Cliniques de Montréal, Montréal, Canada.,Département de Biochimie et Médecine Moléculaire, Faculté de médecine, Université de Montréal, Montréal, Canada.,Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Canada
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9
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Tang Z, Luo W, Huang Z, Yuan M, Wu W, Yang K. Spodoptera frugiperda mRNA export factor interacts with and mediates the nuclear import of Autographa californica multiple nucleopolyhedrovirus ORF34 (Ac34). Virus Res 2021; 299:198438. [PMID: 33901592 DOI: 10.1016/j.virusres.2021.198438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 01/01/2023]
Abstract
Autographa californica multiple nucleopolyhedrovirus orf34 (ac34) is one of the unique genes of alphabaculoviruses. For successful alphabaculovirus replication, viral proteins must be transported to the nucleus. Our previous study showed that the nuclear localization of Ac34 was required for optimal production of budded virions. To investigate the mechanism of Ac34 nuclear import, mass spectrometric analysis was performed to identify potential proteins that may be involved in the nuclear import of Ac34. The result indicated that Spodoptera frugiperda mRNA export factor (SfMEF) may interact with Ac34 during baculovirus infection. Co-immunoprecipitation assays confirmed that Ac34 could interact with SfMEF in the absence of other baculovirus proteins. The deletion of ac34 did not affect the subcellular localization of SfMEF; however, knocking down Sfmef prevented the nuclear import of Ac34 in virus-infected cells. The mutations of C116 or C119 in a potential CCCH zinc finger motif (C116-X2-C119-X8-C128-X2-H131) of Ac34 led to an exclusive cytoplasmic distribution of Ac34, in consistent with our previous finding of mutations of C128 or H131 in this motif. Co-immunoprecipitation analysis showed that the above mutations in the potential zinc finger motif disrupted the interaction between Ac34 and SfMEF, and the loss of the interaction resulted in decreased BV production. Our findings demonstrated that SfMEF interacts with and mediates the nuclear import of Ac34, which is a new nucleocytoplasmic transport pathway used by alphabaculovirus to achieve successful viral replication within the nucleus of the infected cells.
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Affiliation(s)
- Zhimin Tang
- State Key Lab of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Wangtai Luo
- State Key Lab of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Zhihong Huang
- State Key Lab of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Meijin Yuan
- State Key Lab of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Wenbi Wu
- State Key Lab of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Kai Yang
- State Key Lab of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
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10
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Hamed M, Caspar B, Port SA, Kehlenbach RH. A nuclear export sequence promotes CRM1-dependent targeting of the nucleoporin Nup214 to the nuclear pore complex. J Cell Sci 2021; 134:jcs.258095. [PMID: 33589493 DOI: 10.1242/jcs.258095] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/02/2021] [Indexed: 11/20/2022] Open
Abstract
Nup214 is a major nucleoporin on the cytoplasmic side of the nuclear pore complex with roles in late steps of nuclear protein and mRNA export. It interacts with the nuclear export receptor CRM1 (also known as XPO1) via characteristic phenylalanine-glycine (FG) repeats in its C-terminal region. Here, we identify a classic nuclear export sequence (NES) in Nup214 that mediates Ran-dependent binding to CRM1. Nup214 versions with mutations in the NES, as well as wild-type Nup214 in the presence of the selective CRM1 inhibitor leptomycin B, accumulate in the nucleus of Nup214-overexpressing cells. Furthermore, physiological binding partners of Nup214, such as Nup62 and Nup88, are recruited to the nucleus together with Nup214. Nuclear export of mutant Nup214 can be rescued by artificial nuclear export sequences at the C-terminal end of Nup214, leading also to a correct localization of Nup88. Our results suggest a function of the Nup214 NES in the biogenesis of the nuclear pore complex and/or in terminal steps of CRM1-dependent protein export.
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Affiliation(s)
- Mohamed Hamed
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Birgit Caspar
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Sarah A Port
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
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11
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Alzhanova D, Corcoran K, Bailey AG, Long K, Taft-Benz S, Graham RL, Broussard GS, Heise M, Neumann G, Halfmann P, Kawaoka Y, Baric RS, Damania B, Dittmer DP. Novel modulators of p53-signaling encoded by unknown genes of emerging viruses. PLoS Pathog 2021; 17:e1009033. [PMID: 33411764 PMCID: PMC7790267 DOI: 10.1371/journal.ppat.1009033] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 10/06/2020] [Indexed: 02/06/2023] Open
Abstract
The p53 transcription factor plays a key role both in cancer and in the cell-intrinsic response to infections. The ORFEOME project hypothesized that novel p53-virus interactions reside in hitherto uncharacterized, unknown, or hypothetical open reading frames (orfs) of human viruses. Hence, 172 orfs of unknown function from the emerging viruses SARS-Coronavirus, MERS-Coronavirus, influenza, Ebola, Zika (ZIKV), Chikungunya and Kaposi Sarcoma-associated herpesvirus (KSHV) were de novo synthesized, validated and tested in a functional screen of p53 signaling. This screen revealed novel mechanisms of p53 virus interactions and two viral proteins KSHV orf10 and ZIKV NS2A binding to p53. Originally identified as the target of small DNA tumor viruses, these experiments reinforce the notion that all viruses, including RNA viruses, interfere with p53 functions. These results validate this resource for analogous systems biology approaches to identify functional properties of uncharacterized viral proteins, long non-coding RNAs and micro RNAs. New viruses are constantly emerging. The ORFEOME project was based on the hypothesis that every virus, regardless of its molecular makeup and biology should encode functions that intersect the p53 signaling network, since p53 guards the cell from genomic insults, of which depositing a foreign, viral nucleic acid is one. The result of the ORFEOME screen of proteins without any known function, of predicted open reading frames and of suspected non-coding RNAs is the identification of two viral proteins that interact with p53. The first one, orf10, is encoded by Kaposi Sarcoma-associated herpesvirus and the second one, NS2A, is encoded by the Zika virus.
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Affiliation(s)
- Dina Alzhanova
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kathleen Corcoran
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Aubrey G. Bailey
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kristin Long
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Genetics, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Sharon Taft-Benz
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Genetics, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Rachel L. Graham
- Department of Epidemiology, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Grant S. Broussard
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Mark Heise
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Genetics, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Gabriele Neumann
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Peter Halfmann
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Yoshihiro Kawaoka
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Ralph S. Baric
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Epidemiology, University of North Carolina at Chapel Hill, North Carolina, United States of America
| | - Blossom Damania
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Dirk P. Dittmer
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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12
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Michmerhuizen NL, Klco JM, Mullighan CG. Mechanistic insights and potential therapeutic approaches for NUP98-rearranged hematologic malignancies. Blood 2020; 136:2275-2289. [PMID: 32766874 PMCID: PMC7702474 DOI: 10.1182/blood.2020007093] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/21/2020] [Indexed: 12/15/2022] Open
Abstract
Nucleoporin 98 (NUP98) fusion oncoproteins are observed in a spectrum of hematologic malignancies, particularly pediatric leukemias with poor patient outcomes. Although wild-type full-length NUP98 is a member of the nuclear pore complex, the chromosomal translocations leading to NUP98 gene fusions involve the intrinsically disordered and N-terminal region of NUP98 with over 30 partner genes. Fusion partners include several genes bearing homeodomains or having known roles in transcriptional or epigenetic regulation. Based on data in both experimental models and patient samples, NUP98 fusion oncoprotein-driven leukemogenesis is mediated by changes in chromatin structure and gene expression. Multiple cofactors associate with NUP98 fusion oncoproteins to mediate transcriptional changes possibly via phase separation, in a manner likely dependent on the fusion partner. NUP98 gene fusions co-occur with a set of additional mutations, including FLT3-internal tandem duplication and other events contributing to increased proliferation. To improve the currently dire outcomes for patients with NUP98-rearranged malignancies, therapeutic strategies have been considered that target transcriptional and epigenetic machinery, cooperating alterations, and signaling or cell-cycle pathways. With the development of more faithful experimental systems and continued study, we anticipate great strides in our understanding of the molecular mechanisms and therapeutic vulnerabilities at play in NUP98-rearranged models. Taken together, these studies should lead to improved clinical outcomes for NUP98-rearranged leukemia.
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Affiliation(s)
| | - Jeffery M Klco
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN
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13
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Hu M, Bogoyevitch MA, Jans DA. Impact of Respiratory Syncytial Virus Infection on Host Functions: Implications for Antiviral Strategies. Physiol Rev 2020; 100:1527-1594. [PMID: 32216549 DOI: 10.1152/physrev.00030.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Respiratory syncytial virus (RSV) is one of the leading causes of viral respiratory tract infection in infants, the elderly, and the immunocompromised worldwide, causing more deaths each year than influenza. Years of research into RSV since its discovery over 60 yr ago have elucidated detailed mechanisms of the host-pathogen interface. RSV infection elicits widespread transcriptomic and proteomic changes, which both mediate the host innate and adaptive immune responses to infection, and reflect RSV's ability to circumvent the host stress responses, including stress granule formation, endoplasmic reticulum stress, oxidative stress, and programmed cell death. The combination of these events can severely impact on human lungs, resulting in airway remodeling and pathophysiology. The RSV membrane envelope glycoproteins (fusion F and attachment G), matrix (M) and nonstructural (NS) 1 and 2 proteins play key roles in modulating host cell functions to promote the infectious cycle. This review presents a comprehensive overview of how RSV impacts the host response to infection and how detailed knowledge of the mechanisms thereof can inform the development of new approaches to develop RSV vaccines and therapeutics.
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Affiliation(s)
- MengJie Hu
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria, Australia; and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Marie A Bogoyevitch
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria, Australia; and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - David A Jans
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, Victoria, Australia; and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
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14
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Makio T, Wozniak RW. Passive diffusion through nuclear pore complexes regulates levels of the yeast SAGA and SLIK coactivator complexes. J Cell Sci 2020; 133:jcs237156. [PMID: 32051285 DOI: 10.1242/jcs.237156] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 01/31/2020] [Indexed: 11/20/2022] Open
Abstract
Nuclear pore complexes (NPCs) control gene expression by regulating the bi-directional exchange of proteins and RNAs between nuclear and cytoplasmic compartments, including access of transcriptional regulators to the nucleoplasm. Here, we show that the yeast (Saccharomyces cerevisiae) nucleoporin Nup170, in addition to binding and silencing subtelomeric genes, supports transcription of genes regulated by the SAGA transcriptional activator complex. Specifically, we show that a lower amount of SAGA complex is bound to target genes in the absence of Nup170. Consistent with this observation, levels of the SAGA complex are decreased in cells lacking Nup170, while those of the SAGA-related SLIK complexes are increased. This change in the ratio of SAGA to SLIK complexes is due to increased nuclear activity of Pep4, a protease responsible for production of the SLIK complex. Further analyses of various nucleoporin mutants revealed that the increased nuclear entry of Pep4 observed in the nup170Δ mutant likely occurs as the consequence of an increase in the sieving limits of the NPC diffusion channel. On the basis of these results, we propose that changes in passive diffusion rates represent a mechanism for regulating SAGA- and SLIK complex-mediated transcriptional events.
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Affiliation(s)
- Tadashi Makio
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada, T6G 2H7
| | - Richard W Wozniak
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada, T6G 2H7
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15
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Hutten S, Dormann D. Nucleocytoplasmic transport defects in neurodegeneration — Cause or consequence? Semin Cell Dev Biol 2020; 99:151-162. [DOI: 10.1016/j.semcdb.2019.05.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/21/2019] [Accepted: 05/21/2019] [Indexed: 12/12/2022]
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16
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Oka M, Mura S, Otani M, Miyamoto Y, Nogami J, Maehara K, Harada A, Tachibana T, Yoneda Y, Ohkawa Y. Chromatin-bound CRM1 recruits SET-Nup214 and NPM1c onto HOX clusters causing aberrant HOX expression in leukemia cells. eLife 2019; 8:e46667. [PMID: 31755865 PMCID: PMC6874418 DOI: 10.7554/elife.46667] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 10/30/2019] [Indexed: 12/14/2022] Open
Abstract
We previously demonstrated that CRM1, a major nuclear export factor, accumulates at Hox cluster regions to recruit nucleoporin-fusion protein Nup98HoxA9, resulting in robust activation of Hox genes (Oka et al., 2016). However, whether this phenomenon is general to other leukemogenic proteins remains unknown. Here, we show that two other leukemogenic proteins, nucleoporin-fusion SET-Nup214 and the NPM1 mutant, NPM1c, which contains a nuclear export signal (NES) at its C-terminus and is one of the most frequent mutations in acute myeloid leukemia, are recruited to the HOX cluster region via chromatin-bound CRM1, leading to HOX gene activation in human leukemia cells. Furthermore, we demonstrate that this mechanism is highly sensitive to a CRM1 inhibitor in leukemia cell line. Together, these findings indicate that CRM1 acts as a key molecule that connects leukemogenic proteins to aberrant HOX gene regulation either via nucleoporin-CRM1 interaction (for SET-Nup214) or NES-CRM1 interaction (for NPM1c).
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Affiliation(s)
- Masahiro Oka
- Laboratory of Nuclear Transport DynamicsNational Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN)OsakaJapan
- Laboratory of Biomedical Innovation, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
| | - Sonoko Mura
- Biomolecular Dynamics Group, Graduate School of Frontier BiosciencesOsaka UniversityOsakaJapan
| | - Mayumi Otani
- Laboratory of Nuclear Transport DynamicsNational Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN)OsakaJapan
| | - Yoichi Miyamoto
- Laboratory of Nuclear Transport DynamicsNational Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN)OsakaJapan
| | - Jumpei Nogami
- Department of Advanced Medical Initiatives, Faculty of MedicineKyushu UniversityFukuokaJapan
| | - Kazumitsu Maehara
- Department of Advanced Medical Initiatives, Faculty of MedicineKyushu UniversityFukuokaJapan
| | - Akihito Harada
- Department of Advanced Medical Initiatives, Faculty of MedicineKyushu UniversityFukuokaJapan
| | - Taro Tachibana
- Department of Bioengineering, Graduate School of EngineeringOsaka City UniversityOsakaJapan
| | - Yoshihiro Yoneda
- Laboratory of Biomedical Innovation, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
- National Institutes of Biomedical Innovation, Health and Nutrition (NIBIOHN)OsakaJapan
| | - Yasuyuki Ohkawa
- Department of Advanced Medical Initiatives, Faculty of MedicineKyushu UniversityFukuokaJapan
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17
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Mendes A, Fahrenkrog B. NUP214 in Leukemia: It's More than Transport. Cells 2019; 8:cells8010076. [PMID: 30669574 PMCID: PMC6356203 DOI: 10.3390/cells8010076] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/10/2019] [Accepted: 01/17/2019] [Indexed: 12/15/2022] Open
Abstract
NUP214 is a component of the nuclear pore complex (NPC) with a key role in protein and mRNA nuclear export. Chromosomal translocations involving the NUP214 locus are recurrent in acute leukemia and frequently fuse the C-terminal region of NUP214 with SET and DEK, two chromatin remodeling proteins with roles in transcription regulation. SET-NUP214 and DEK-NUP214 fusion proteins disrupt protein nuclear export by inhibition of the nuclear export receptor CRM1, which results in the aberrant accumulation of CRM1 protein cargoes in the nucleus. SET-NUP214 is primarily associated with acute lymphoblastic leukemia (ALL), whereas DEK-NUP214 exclusively results in acute myeloid leukemia (AML), indicating different leukemogenic driver mechanisms. Secondary mutations in leukemic blasts may contribute to the different leukemia outcomes. Additional layers of complexity arise from the respective functions of SET and DEK in transcription regulation and chromatin remodeling, which may drive malignant hematopoietic transformation more towards ALL or AML. Another, less frequent fusion protein involving the C terminus of NUP214 results in the sequestosome-1 (SQSTM1)-NUP214 chimera, which was detected in ALL. SQSTM1 is a ubiquitin-binding protein required for proper autophagy induction, linking the NUP214 fusion protein to yet another cellular mechanism. The scope of this review is to summarize the general features of NUP214-related leukemia and discuss how distinct chromosomal translocation partners can influence the cellular effects of NUP214 fusion proteins in leukemia.
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Affiliation(s)
- Adélia Mendes
- Institute of Biology and Molecular Medicine, Université Libre de Bruxelles, 6041 Charleroi, Belgium.
| | - Birthe Fahrenkrog
- Institute of Biology and Molecular Medicine, Université Libre de Bruxelles, 6041 Charleroi, Belgium.
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18
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Ha M, Kim JY, Han ME, Kim GH, Park SY, Jeong DC, Oh SO, Kim YH. TMEM18: A Novel Prognostic Marker in Acute Myeloid Leukemia. Acta Haematol 2018; 140:71-76. [PMID: 30199869 DOI: 10.1159/000492742] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/04/2018] [Indexed: 12/15/2022]
Abstract
BACKGROUND Certain nuclear envelope proteins are associated with important cancer cell characteristics, including migration and proliferation. Abnormal expression of and genetic changes in nuclear envelope proteins have been reported in acute myeloid leukemia (AML) patients. Transmembrane protein 18 (TMEM18), a nuclear envelope protein, is involved in neural stem cell migration and tumorigenicity. METHODS To examine the prognostic significance of TMEM18 in AML patients, we analyzed an AML cohort from The Cancer Genome Atlas (TCGA, n = 142). RESULTS Kaplan-Meier survival analysis revealed that TMEM18 overexpression was associated with a better AML prognosis with good discrimination (p = 0.019). Interestingly, this ability to predict the prognosis was significant in male AML patients, but not in female ones. C-index and area-under-the-curve analyses further supported this discriminative ability and multivariate analysis confirmed its prognostic significance (p = 0.00347). Correlation analysis revealed that TMEM18 had a statistically significant positive correlation with nuclear envelop protein 133 (NUP133), NUP35, NUP54, NUP62, and NUP88. CONCLUSION Because the current AML prognostic factors do not take mRNA expression into consideration unlike other cancers, the development of mRNA-based prognostic factors would be beneficial for accurate prediction of the survival of AML patients. Therefore, TMEM18 gene is a potential biomarker for AML.
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Affiliation(s)
- Mihyang Ha
- Department of Anatomy, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Ji-Young Kim
- Department of Anatomy, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Myoung-Eun Han
- Department of Anatomy, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Ga Hyun Kim
- Department of Anatomy, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Si Young Park
- Department of Anatomy, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Dae Cheon Jeong
- Deloitte Analytics Group, Deloitte Consulting LLC, Seoul, Republic of Korea
| | - Sae-Ock Oh
- Department of Anatomy, School of Medicine, Pusan National University, Yangsan, Republic of Korea
| | - Yun Hak Kim
- Department of Anatomy, School of Medicine, Pusan National University, Yangsan, Republic of Korea
- BEER, Busan Society of Evidence-Based Medicine and Research, Busan, Republic of Korea
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19
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Furusawa Y, Yamada S, Kawaoka Y. Host Factor Nucleoporin 93 Is Involved in the Nuclear Export of Influenza Virus RNA. Front Microbiol 2018; 9:1675. [PMID: 30087672 PMCID: PMC6066526 DOI: 10.3389/fmicb.2018.01675] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/04/2018] [Indexed: 11/13/2022] Open
Abstract
Influenza virus replication relies on the functions of host factors. In our previous study, we identified host factors involved in virus replication and began analyses of their roles in this process. In this study, we focused on Nucleoporin 93 (NUP93) and revealed its importance in influenza virus replication. NUP93 knockdown mediated by siRNAs reduced viral replication and decreased the efficiency of the early step of the viral life cycle. NUP93 did not appear to be important for virus binding, internalization, or the nuclear import of viral ribonucleoprotein (vRNP); however, in NUP93-depleted cells, viral RNA accumulated in the nucleus. These results suggest that NUP93 is involved in the nuclear export of viral RNA.
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Affiliation(s)
- Yuri Furusawa
- Division of Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Shinya Yamada
- Division of Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yoshihiro Kawaoka
- Division of Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States.,Department of Special Pathogens, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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20
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Capitanio JS, Montpetit B, Wozniak RW. Nucleoplasmic Nup98 controls gene expression by regulating a DExH/D-box protein. Nucleus 2017; 9:1-8. [PMID: 28934014 PMCID: PMC5973140 DOI: 10.1080/19491034.2017.1364826] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The nucleoporin Nup98 has been linked to the regulation of transcription and RNA metabolism, 1-3 but the mechanisms by which Nup98 contributes to these processes remains largely undefined. Recently, we uncovered interactions between Nup98 and several DExH/D-box proteins (DBPs), a protein family well-known for modulating gene expression and RNA metabolism. 4-6 Analysis of Nup98 and one of these DBPs, DHX9, showed that they directly interact, their association is facilitated by RNA, and Nup98 binding stimulates DHX9 ATPase activity. 7 Furthermore, these proteins were dependent on one another for their proper association with a subset of gene loci to control transcription and modulate mRNA splicing. 7 On the basis of these observations, we proposed that Nup98 functions to regulate DHX9 activity within the nucleoplasm. 7 Since Nup98 is associated with several DBPs, regulation of DHX9 by Nup98 may represent a paradigm for understanding how Nup98, and possibly other FG-Nup proteins, could direct the diverse cellular activities of multiple DBPs.
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Affiliation(s)
| | - Ben Montpetit
- a Department of Cell Biology , University of Alberta , Edmonton , Canada.,b Department of Viticulture and Enology , University of California at Davis , Davis , CA , USA
| | - Richard W Wozniak
- a Department of Cell Biology , University of Alberta , Edmonton , Canada
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21
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Reprint of: Importins in the maintenance and lineage commitment of ES cells. Neurochem Int 2017; 106:14-23. [PMID: 28550879 DOI: 10.1016/j.neuint.2017.01.022] [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: 08/31/2016] [Revised: 01/25/2017] [Accepted: 01/30/2017] [Indexed: 11/23/2022]
Abstract
The nucleus of a eukaryotic cell is separated from the cytoplasm by a nuclear envelope, and nuclear pores within the envelope facilitate nucleocytoplasmic transport and the exchange of information. Gene regulation is a key component of biological activity regulation in the cell. Transcription factors control the expression levels of various genes that are necessary for the maintenance or conversion of cellular states during animal development. Because transcription factor activities determine the extent of transcription of target genes, the number of active transcription factors must be tightly regulated. In this regard, the nuclear translocation of a transcription factor is an important determinant of its activity. Therefore, it is becoming clear that the nucleocytoplasmic transport machinery is involved in cell differentiation and organism development. This review examines the regulation of transcription factors by the nucleocytoplasmic transport machinery in ES cells.
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22
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Saito S, Yokokawa T, Iizuka G, Cigdem S, Okuwaki M, Nagata K. Function of Nup98 subtypes and their fusion proteins, Nup98-TopIIβ and Nup98-SETBP1 in nuclear-cytoplasmic transport. Biochem Biophys Res Commun 2017; 487:96-102. [PMID: 28392395 DOI: 10.1016/j.bbrc.2017.04.024] [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: 03/28/2017] [Accepted: 04/06/2017] [Indexed: 12/12/2022]
Abstract
Nup98 is a component of the nuclear pore complex. The nup98-fusion genes derived by chromosome translocations are involved in hematopoietic malignancies. Here, we investigated the functions of Nup98 isoforms and two unexamined Nup98-fusion proteins, Nup98-TopIIβ and Nup98-SETBP1. We first demonstrated that two Nup98 isoforms are expressed in various mouse tissues and similarly localized in the nucleus and the nuclear envelope. We also showed that Nup98-TopIIβ and Nup98-SETBP1 are localized in the nucleus and partially co-localized with full-length Nup98 and a nuclear export receptor XPO1. We demonstrated that Nup98-TopIIβ and Nup98-SETBP1 negatively regulate the XPO1-mediated protein export. Our results will contribute to the understanding of the molecular mechanism by which the Nup98-fusion proteins induce tumorigenesis.
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Affiliation(s)
- Shoko Saito
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.
| | - Takafumi Yokokawa
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Gemmei Iizuka
- School of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Sadik Cigdem
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Mitsuru Okuwaki
- Department of Infection Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
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23
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Capitanio JS, Montpetit B, Wozniak RW. Human Nup98 regulates the localization and activity of DExH/D-box helicase DHX9. eLife 2017; 6. [PMID: 28221134 PMCID: PMC5338925 DOI: 10.7554/elife.18825] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 02/16/2017] [Indexed: 12/17/2022] Open
Abstract
Beyond their role at nuclear pore complexes, some nucleoporins function in the nucleoplasm. One such nucleoporin, Nup98, binds chromatin and regulates gene expression. To gain insight into how Nup98 contributes to this process, we focused on identifying novel binding partners and understanding the significance of these interactions. Here we report on the identification of the DExH/D-box helicase DHX9 as an intranuclear Nup98 binding partner. Various results, including in vitro assays, show that the FG/GLFG region of Nup98 binds to N- and C-terminal regions of DHX9 in an RNA facilitated manner. Importantly, binding of Nup98 stimulates the ATPase activity of DHX9, and a transcriptional reporter assay suggests Nup98 supports DHX9-stimulated transcription. Consistent with these observations, our analysis revealed that Nup98 and DHX9 bind interdependently to similar gene loci and their transcripts. Based on our results, we propose that Nup98 functions as a co-factor that regulates DHX9 and, potentially, other RNA helicases.
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Affiliation(s)
| | - Ben Montpetit
- Department of Cell Biology, University of Alberta, Edmonton, Canada.,Department of Viticulture and Enology, University of California, Davis, United states
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24
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Importins in the maintenance and lineage commitment of ES cells. Neurochem Int 2017; 105:32-41. [PMID: 28163061 DOI: 10.1016/j.neuint.2017.01.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/25/2017] [Accepted: 01/30/2017] [Indexed: 11/23/2022]
Abstract
The nucleus of a eukaryotic cell is separated from the cytoplasm by a nuclear envelope, and nuclear pores within the envelope facilitate nucleocytoplasmic transport and the exchange of information. Gene regulation is a key component of biological activity regulation in the cell. Transcription factors control the expression levels of various genes that are necessary for the maintenance or conversion of cellular states during animal development. Because transcription factor activities determine the extent of transcription of target genes, the number of active transcription factors must be tightly regulated. In this regard, the nuclear translocation of a transcription factor is an important determinant of its activity. Therefore, it is becoming clear that the nucleocytoplasmic transport machinery is involved in cell differentiation and organism development. This review examines the regulation of transcription factors by the nucleocytoplasmic transport machinery in ES cells.
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25
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Pan M, Zhang Q, Liu P, Huang J, Wang Y, Chen S. Inhibition of the nuclear export of p65 and IQCG in leukemogenesis by NUP98-IQCG. Front Med 2016; 10:410-419. [PMID: 27864780 DOI: 10.1007/s11684-016-0489-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 09/29/2016] [Indexed: 01/04/2023]
Abstract
NUP98 fuses with approximately 34 different partner genes via translocation in hematological malignancies. Transgenic or retrovirus-mediated bone marrow transplanted mouse models reveal the leukemogenesis of some NUP98-related fusion genes. We previously reported the fusion protein NUP98-IQ motif containing G (IQCG) in a myeloid/T lymphoid bi-phenoleukemia patient with t(3;11) and confirmed its leukemogenic ability. Herein, we demonstrated the association of NUP98-IQCG with CRM1, and found that NUP98-IQCG expression inhibits the CRM1-mediated nuclear export of p65 and enhances the transcriptional activity of nuclear factor-κB. Moreover, IQCG could be entrapped in the nucleus by NUP98-IQCG, and the fusion protein interacts with calmodulin via the IQ motif in a calcium-independent manner. Therefore, the inhibition of nuclear exports of p65 and IQCG might contribute to the leukemogenesis of NUP98-IQCG.
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Affiliation(s)
- Mengmeng Pan
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Rui Jin Hospital Affiliated to Shanghai Jiao Tong University (SJTU) School of Medicine, Shanghai, 200025, China
| | - Qiyao Zhang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Rui Jin Hospital Affiliated to Shanghai Jiao Tong University (SJTU) School of Medicine, Shanghai, 200025, China
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences and SJTU School of Medicine, Shanghai, 200025, China
| | - Ping Liu
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Rui Jin Hospital Affiliated to Shanghai Jiao Tong University (SJTU) School of Medicine, Shanghai, 200025, China
| | - Jinyan Huang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Rui Jin Hospital Affiliated to Shanghai Jiao Tong University (SJTU) School of Medicine, Shanghai, 200025, China
| | - Yueying Wang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Rui Jin Hospital Affiliated to Shanghai Jiao Tong University (SJTU) School of Medicine, Shanghai, 200025, China.
| | - Saijuan Chen
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Rui Jin Hospital Affiliated to Shanghai Jiao Tong University (SJTU) School of Medicine, Shanghai, 200025, China.
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences and SJTU School of Medicine, Shanghai, 200025, China.
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Port SA, Mendes A, Valkova C, Spillner C, Fahrenkrog B, Kaether C, Kehlenbach RH. The Oncogenic Fusion Proteins SET-Nup214 and Sequestosome-1 (SQSTM1)-Nup214 Form Dynamic Nuclear Bodies and Differentially Affect Nuclear Protein and Poly(A)+ RNA Export. J Biol Chem 2016; 291:23068-23083. [PMID: 27613868 PMCID: PMC5087727 DOI: 10.1074/jbc.m116.735340] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 08/31/2016] [Indexed: 01/09/2023] Open
Abstract
Genetic rearrangements are a hallmark of several forms of leukemia and can lead to oncogenic fusion proteins. One example of an affected chromosomal region is the gene coding for Nup214, a nucleoporin that localizes to the cytoplasmic side of the nuclear pore complex (NPC). We investigated two such fusion proteins, SET-Nup214 and SQSTM1 (sequestosome)-Nup214, both containing C-terminal portions of Nup214. SET-Nup214 nuclear bodies containing the nuclear export receptor CRM1 were observed in the leukemia cell lines LOUCY and MEGAL. Overexpression of SET-Nup214 in HeLa cells leads to the formation of similar nuclear bodies that recruit CRM1, export cargo proteins, and certain nucleoporins and concomitantly affect nuclear protein and poly(A)+ RNA export. SQSTM1-Nup214, although mostly cytoplasmic, also forms nuclear bodies and inhibits nuclear protein but not poly(A)+ RNA export. The interaction of the fusion proteins with CRM1 is RanGTP-dependent, as shown in co-immunoprecipitation experiments and binding assays. Further analysis revealed that the Nup214 parts mediate the inhibition of nuclear export, whereas the SET or SQSTM1 part determines the localization of the fusion protein and therefore the extent of the effect. SET-Nup214 nuclear bodies are highly mobile structures, which are in equilibrium with the nucleoplasm in interphase and disassemble during mitosis or upon treatment of cells with the CRM1-inhibitor leptomycin B. Strikingly, we found that nucleoporins can be released from nuclear bodies and reintegrated into existing NPC. Our results point to nuclear bodies as a means of preventing the formation of potentially insoluble and harmful protein aggregates that also may serve as storage compartments for nuclear transport factors.
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Affiliation(s)
- Sarah A Port
- From the Department of Molecular Biology, Faculty of Medicine and the Göttingen Center for Molecular Biosciences (GZMB), Georg August University, Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Adélia Mendes
- the Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, 6041 Charleroi, Belgium, and
| | - Christina Valkova
- the Leibniz Institute on Aging,Fritz Lipmann Institute, Beutenbergstrasse 11, 07745 Jena, Germany
| | - Christiane Spillner
- From the Department of Molecular Biology, Faculty of Medicine and the Göttingen Center for Molecular Biosciences (GZMB), Georg August University, Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Birthe Fahrenkrog
- the Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, 6041 Charleroi, Belgium, and
| | - Christoph Kaether
- the Leibniz Institute on Aging,Fritz Lipmann Institute, Beutenbergstrasse 11, 07745 Jena, Germany
| | - Ralph H Kehlenbach
- From the Department of Molecular Biology, Faculty of Medicine and the Göttingen Center for Molecular Biosciences (GZMB), Georg August University, Göttingen, Humboldtallee 23, 37073 Göttingen, Germany,
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Genenncher B, Wirthmueller L, Roth C, Klenke M, Ma L, Sharon A, Wiermer M. Nucleoporin-Regulated MAP Kinase Signaling in Immunity to a Necrotrophic Fungal Pathogen. PLANT PHYSIOLOGY 2016; 172:1293-1305. [PMID: 27591188 PMCID: PMC5047096 DOI: 10.1104/pp.16.00832] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/31/2016] [Indexed: 05/26/2023]
Abstract
Pathogen-responsive mitogen-activated protein kinase (MAPK or MPK) cascades relay signals from activated immune receptors across the nuclear envelope to intranuclear targets. However, in plants, little is known about the spatial control of MAPK signaling. Here, we report that the Arabidopsis (Arabidopsis thaliana) nuclear pore complex protein Nup88/MOS7 is essential for immunity to the necrotrophic fungus Botrytis cinerea The mos7-1 mutation, causing a four-amino acid deletion, compromises B. cinerea-induced activation of the key immunoregulatory MAPKs MPK3/MPK6 and reduces MPK3 protein levels posttranscriptionally. Furthermore, MOS7 contributes to retaining a sufficient MPK3 abundance in the nucleus, which is required for full immunity to B. cinerea Finally, we present a structural model of MOS7 and show that the mos7-1 mutation compromises interactions with Nup98a/b, two phenylalanine-glycine repeat nucleoporins implicated in maintaining the selective nuclear pore complex permeability barrier. Together, our analysis uncovered MOS7 and Nup98 as novel components of plant immunity toward a necrotrophic pathogen and provides mechanistic insights into how these nucleoporins coordinate nucleocytoplasmic transport to mount a robust immune response.
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Affiliation(s)
- Bianca Genenncher
- Department of Plant Cell Biology, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Göttingen, Germany (B.G., C.R., M.K., M.W.);Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany (L.W.); andDepartment of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (L.M., A.S.)
| | - Lennart Wirthmueller
- Department of Plant Cell Biology, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Göttingen, Germany (B.G., C.R., M.K., M.W.);Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany (L.W.); andDepartment of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (L.M., A.S.)
| | - Charlotte Roth
- Department of Plant Cell Biology, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Göttingen, Germany (B.G., C.R., M.K., M.W.);Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany (L.W.); andDepartment of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (L.M., A.S.)
| | - Melanie Klenke
- Department of Plant Cell Biology, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Göttingen, Germany (B.G., C.R., M.K., M.W.);Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany (L.W.); andDepartment of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (L.M., A.S.)
| | - Liang Ma
- Department of Plant Cell Biology, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Göttingen, Germany (B.G., C.R., M.K., M.W.);Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany (L.W.); andDepartment of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (L.M., A.S.)
| | - Amir Sharon
- Department of Plant Cell Biology, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Göttingen, Germany (B.G., C.R., M.K., M.W.);Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany (L.W.); andDepartment of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (L.M., A.S.)
| | - Marcel Wiermer
- Department of Plant Cell Biology, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Göttingen, Germany (B.G., C.R., M.K., M.W.);Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 14195 Berlin, Germany (L.W.); andDepartment of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (L.M., A.S.)
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Leukemia-Associated Nup214 Fusion Proteins Disturb the XPO1-Mediated Nuclear-Cytoplasmic Transport Pathway and Thereby the NF-κB Signaling Pathway. Mol Cell Biol 2016; 36:1820-35. [PMID: 27114368 DOI: 10.1128/mcb.00158-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 04/14/2016] [Indexed: 02/07/2023] Open
Abstract
Nuclear-cytoplasmic transport through nuclear pore complexes is mediated by nuclear transport receptors. Previous reports have suggested that aberrant nuclear-cytoplasmic transport due to mutations or overexpression of nuclear pore complexes and nuclear transport receptors is closely linked to diseases. Nup214, a component of nuclear pore complexes, has been found as chimeric fusion proteins in leukemia. Among various Nup214 fusion proteins, SET-Nup214 and DEK-Nup214 have been shown to be engaged in tumorigenesis, but their oncogenic mechanisms remain unclear. In this study, we examined the functions of the Nup214 fusion proteins by focusing on their effects on nuclear-cytoplasmic transport. We found that SET-Nup214 and DEK-Nup214 interact with exportin-1 (XPO1)/CRM1 and nuclear RNA export factor 1 (NXF1)/TAP, which mediate leucine-rich nuclear export signal (NES)-dependent protein export and mRNA export, respectively. SET-Nup214 and DEK-Nup214 decreased the XPO1-mediated nuclear export of NES proteins such as cyclin B and proteins involved in the NF-κB signaling pathway by tethering XPO1 onto nuclear dots where Nup214 fusion proteins are localized. We also demonstrated that SET-Nup214 and DEK-Nup214 expression inhibited NF-κB-mediated transcription by abnormal tethering of the complex containing p65 and its inhibitor, IκB, in the nucleus. These results suggest that SET-Nup214 and DEK-Nup214 perturb the regulation of gene expression through alteration of the nuclear-cytoplasmic transport system.
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29
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Soheilypour M, Peyro M, Jahed Z, Mofrad MRK. On the Nuclear Pore Complex and Its Roles in Nucleo-Cytoskeletal Coupling and Mechanobiology. Cell Mol Bioeng 2016. [DOI: 10.1007/s12195-016-0443-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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30
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Fahrenkrog B, Martinelli V, Nilles N, Fruhmann G, Chatel G, Juge S, Sauder U, Di Giacomo D, Mecucci C, Schwaller J. Expression of Leukemia-Associated Nup98 Fusion Proteins Generates an Aberrant Nuclear Envelope Phenotype. PLoS One 2016; 11:e0152321. [PMID: 27031510 PMCID: PMC4816316 DOI: 10.1371/journal.pone.0152321] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 03/11/2016] [Indexed: 01/15/2023] Open
Abstract
Chromosomal translocations involving the nucleoporin NUP98 have been described in several hematopoietic malignancies, in particular acute myeloid leukemia (AML). In the resulting chimeric proteins, Nup98's N-terminal region is fused to the C-terminal region of about 30 different partners, including homeodomain (HD) transcription factors. While transcriptional targets of distinct Nup98 chimeras related to immortalization are relatively well described, little is known about other potential cellular effects of these fusion proteins. By comparing the sub-nuclear localization of a large number of Nup98 fusions with HD and non-HD partners throughout the cell cycle we found that while all Nup98 chimeras were nuclear during interphase, only Nup98-HD fusion proteins exhibited a characteristic speckled appearance. During mitosis, only Nup98-HD fusions were concentrated on chromosomes. Despite the difference in localization, all tested Nup98 chimera provoked morphological alterations in the nuclear envelope (NE), in particular affecting the nuclear lamina and the lamina-associated polypeptide 2α (LAP2α). Importantly, such aberrations were not only observed in transiently transfected HeLa cells but also in mouse bone marrow cells immortalized by Nup98 fusions and in cells derived from leukemia patients harboring Nup98 fusions. Our findings unravel Nup98 fusion-associated NE alterations that may contribute to leukemogenesis.
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MESH Headings
- Animals
- Bone Marrow Cells/metabolism
- Bone Marrow Cells/pathology
- Cell Cycle
- DNA-Binding Proteins/analysis
- DNA-Binding Proteins/metabolism
- HeLa Cells
- Homeodomain Proteins/analysis
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Humans
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Leukemia, Myeloid, Acute/pathology
- Membrane Proteins/analysis
- Membrane Proteins/metabolism
- Mice
- Mitosis
- Nuclear Envelope/genetics
- Nuclear Envelope/metabolism
- Nuclear Envelope/pathology
- Nuclear Pore Complex Proteins/analysis
- Nuclear Pore Complex Proteins/genetics
- Nuclear Pore Complex Proteins/metabolism
- Oncogene Proteins, Fusion/analysis
- Oncogene Proteins, Fusion/genetics
- Oncogene Proteins, Fusion/metabolism
- Phenotype
- Translocation, Genetic
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Affiliation(s)
- Birthe Fahrenkrog
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, Charleroi, Belgium
- * E-mail: (BF); (JS)
| | - Valérie Martinelli
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, Charleroi, Belgium
| | - Nadine Nilles
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, Charleroi, Belgium
| | - Gernot Fruhmann
- Department of Biomedicine, University Children’s Hospital Basel, Basel, Switzerland
| | - Guillaume Chatel
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, Charleroi, Belgium
| | - Sabine Juge
- Department of Biomedicine, University Children’s Hospital Basel, Basel, Switzerland
| | - Ursula Sauder
- Biozentrum, Microscopy Center, University of Basel, Basel, Switzerland
| | - Danika Di Giacomo
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, Perugia, Italy
| | - Cristina Mecucci
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, Perugia, Italy
| | - Jürg Schwaller
- Department of Biomedicine, University Children’s Hospital Basel, Basel, Switzerland
- * E-mail: (BF); (JS)
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31
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Oka M, Mura S, Yamada K, Sangel P, Hirata S, Maehara K, Kawakami K, Tachibana T, Ohkawa Y, Kimura H, Yoneda Y. Chromatin-prebound Crm1 recruits Nup98-HoxA9 fusion to induce aberrant expression of Hox cluster genes. eLife 2016; 5:e09540. [PMID: 26740045 PMCID: PMC4718815 DOI: 10.7554/elife.09540] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 11/16/2015] [Indexed: 01/14/2023] Open
Abstract
The nucleoporin Nup98 is frequently rearranged to form leukemogenic Nup98-fusion proteins with various partners. However, their function remains largely elusive. Here, we show that Nup98-HoxA9, a fusion between Nup98 and the homeobox transcription factor HoxA9, forms nuclear aggregates that frequently associate with facultative heterochromatin. We demonstrate that stable expression of Nup98-HoxA9 in mouse embryonic stem cells selectively induces the expression of Hox cluster genes. Genome-wide binding site analysis revealed that Nup98-HoxA9 is preferentially targeted and accumulated at Hox cluster regions where the export factor Crm1 is originally prebound. In addition, leptomycin B, an inhibitor of Crm1, disassembled nuclear Nup98-HoxA9 dots, resulting in the loss of chromatin binding of Nup98-HoxA9 and Nup98-HoxA9-mediated activation of Hox genes. Collectively, our results indicate that highly selective targeting of Nup98-fusion proteins to Hox cluster regions via prebound Crm1 induces the formation of higher order chromatin structures that causes aberrant Hox gene regulation.
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Affiliation(s)
- Masahiro Oka
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
- Laboratory of Biomedical Innovation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Sonoko Mura
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Kohji Yamada
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - Percival Sangel
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - Saki Hirata
- Department of Advanced Medical Initiatives, Kyushu University, Fukuoka, Japan
| | - Kazumitsu Maehara
- Department of Advanced Medical Initiatives, Kyushu University, Fukuoka, Japan
| | - Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, Shizuoka, Japan
| | - Taro Tachibana
- Department of Bioengineering, Osaka City University, Graduate School of Engineering, Osaka, Japan
| | - Yasuyuki Ohkawa
- Department of Advanced Medical Initiatives, Kyushu University, Fukuoka, Japan
| | - Hiroshi Kimura
- Department of Biological Sciences, Graduate School of Bioscience and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yoshihiro Yoneda
- Laboratory of Biomedical Innovation, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
- National Institutes of Biomedical Innovation, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
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32
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Formation of Nup98-containing nuclear bodies in HeLa sublines is linked to genomic rearrangements affecting chromosome 11. Chromosoma 2015; 125:789-805. [PMID: 26685999 DOI: 10.1007/s00412-015-0567-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/06/2015] [Accepted: 12/10/2015] [Indexed: 01/23/2023]
Abstract
Nup98 is an important component of the nuclear pore complex (NPC) and also a rare but recurrent target for chromosomal translocation in leukaemogenesis. Nup98 contains multiple cohesive Gly-Leu-Phe-Gly (GLFG) repeats that are critical notably for the formation of intranuclear GLFG bodies. Previous studies have reported the existence of GLFG bodies in cells overexpressing exogenous Nup98 or in a HeLa subline (HeLa-C) expressing an unusual elevated amount of endogenous Nup98. Here, we have analysed the presence of Nup98-containing bodies in several human cell lines. We found that HEp-2, another HeLa subline, contains GLFG bodies that are distinct from those identified in HeLa-C. Rapid amplification of cDNA ends (RACE) revealed that HEp-2 cells express additional truncated forms of Nup98 fused to a non-coding region of chromosome 11q22.1. Cytogenetic analyses using FISH and array-CGH further revealed chromosomal rearrangements that were distinct from those observed in leukaemic cells. Indeed, HEp-2 cells feature a massive amplification of juxtaposed NUP98 and 11q22.1 loci on a chromosome marker derived from chromosome 3. Unexpectedly, minor co-amplifications of NUP98 and 11q22.1 loci were also observed in other HeLa sublines, but on rearranged chromosomes 11. Altogether, this study reveals that distinct genomic rearrangements affecting NUP98 are associated with the formation of GLFG bodies in specific HeLa sublines.
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33
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Port SA, Monecke T, Dickmanns A, Spillner C, Hofele R, Urlaub H, Ficner R, Kehlenbach RH. Structural and Functional Characterization of CRM1-Nup214 Interactions Reveals Multiple FG-Binding Sites Involved in Nuclear Export. Cell Rep 2015; 13:690-702. [PMID: 26489467 DOI: 10.1016/j.celrep.2015.09.042] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/11/2015] [Accepted: 09/14/2015] [Indexed: 12/11/2022] Open
Abstract
CRM1 is the major nuclear export receptor. During translocation through the nuclear pore, transport complexes transiently interact with phenylalanine-glycine (FG) repeats of multiple nucleoporins. On the cytoplasmic side of the nuclear pore, CRM1 tightly interacts with the nucleoporin Nup214. Here, we present the crystal structure of a 117-amino-acid FG-repeat-containing fragment of Nup214, in complex with CRM1, Snurportin 1, and RanGTP at 2.85 Å resolution. The structure reveals eight binding sites for Nup214 FG motifs on CRM1, with intervening stretches that are loosely attached to the transport receptor. Nup214 binds to N- and C-terminal regions of CRM1, thereby clamping CRM1 in a closed conformation and stabilizing the export complex. The role of conserved hydrophobic pockets for the recognition of FG motifs was analyzed in biochemical and cell-based assays. Comparative studies with RanBP3 and Nup62 shed light on specificities of CRM1-nucleoporin binding, which serves as a paradigm for transport receptor-nucleoporin interactions.
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Affiliation(s)
- Sarah A Port
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Thomas Monecke
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany
| | - Achim Dickmanns
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany
| | - Christiane Spillner
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Romina Hofele
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany; Bioanalytics, Institute for Clinical Chemistry, University Medical Center, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany; Bioanalytics, Institute for Clinical Chemistry, University Medical Center, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.
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Dickmanns A, Monecke T, Ficner R. Structural Basis of Targeting the Exportin CRM1 in Cancer. Cells 2015; 4:538-68. [PMID: 26402707 PMCID: PMC4588050 DOI: 10.3390/cells4030538] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/07/2015] [Accepted: 09/11/2015] [Indexed: 12/19/2022] Open
Abstract
Recent studies have demonstrated the interference of nucleocytoplasmic trafficking with the establishment and maintenance of various cancers. Nucleocytoplasmic transport is highly regulated and coordinated, involving different nuclear transport factors or receptors, importins and exportins, that mediate cargo transport from the cytoplasm into the nucleus or the other way round, respectively. The exportin CRM1 (Chromosome region maintenance 1) exports a plethora of different protein cargoes and ribonucleoprotein complexes. Structural and biochemical analyses have enabled the deduction of individual steps of the CRM1 transport cycle. In addition, CRM1 turned out to be a valid target for anticancer drugs as it exports numerous proto-oncoproteins and tumor suppressors. Clearly, detailed understanding of the flexibility, regulatory features and cooperative binding properties of CRM1 for Ran and cargo is a prerequisite for the design of highly effective drugs. The first compound found to inhibit CRM1-dependent nuclear export was the natural drug Leptomycin B (LMB), which blocks export by competitively interacting with a highly conserved cleft on CRM1 required for nuclear export signal recognition. Clinical studies revealed serious side effects of LMB, leading to a search for alternative natural and synthetic drugs and hence a multitude of novel therapeutics. The present review examines recent progress in understanding the binding mode of natural and synthetic compounds and their inhibitory effects.
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Affiliation(s)
- Achim Dickmanns
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, Göttingen 37077, Germany.
| | - Thomas Monecke
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, Göttingen 37077, Germany.
| | - Ralf Ficner
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, Göttingen 37077, Germany.
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35
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Dickmanns A, Kehlenbach RH, Fahrenkrog B. Nuclear Pore Complexes and Nucleocytoplasmic Transport: From Structure to Function to Disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 320:171-233. [PMID: 26614874 DOI: 10.1016/bs.ircmb.2015.07.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nucleocytoplasmic transport is an essential cellular activity and occurs via nuclear pore complexes (NPCs) that reside in the double membrane of the nuclear envelope. Significant progress has been made during the past few years in unravelling the ultrastructural organization of NPCs and their constituents, the nucleoporins, by cryo-electron tomography and X-ray crystallography. Mass spectrometry and genomic approaches have provided deeper insight into the specific regulation and fine tuning of individual nuclear transport pathways. Recent research has also focused on the roles nucleoporins play in health and disease, some of which go beyond nucleocytoplasmic transport. Here we review emerging results aimed at understanding NPC architecture and nucleocytoplasmic transport at the atomic level, elucidating the specific function individual nucleoporins play in nuclear trafficking, and finally lighting up the contribution of nucleoporins and nuclear transport receptors in human diseases, such as cancer and certain genetic disorders.
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Affiliation(s)
- Achim Dickmanns
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University of Göttingen, Göttingen, Germany
| | - Birthe Fahrenkrog
- Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, Charleroi, Belgium
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36
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Qiu JJ, Zeisig BB, Li S, Liu W, Chu H, Song Y, Giordano A, Schwaller J, Gronemeyer H, Dong S, So CWE. Critical role of retinoid/rexinoid signaling in mediating transformation and therapeutic response of NUP98-RARG leukemia. Leukemia 2015; 29:1153-62. [PMID: 25510432 DOI: 10.1038/leu.2014.334] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 09/12/2014] [Accepted: 09/15/2014] [Indexed: 01/12/2023]
Abstract
While the nucleoporin 98-retinoic acid receptor gamma (NUP98-RARG) is the first RARG fusion protein found in acute leukemia, its roles and the molecular basis in oncogenic transformation are currently unknown. Here, we showed that homodimeric NUP98-RARG not only acquired unique nuclear localization pattern and ability of recruiting both RXRA and wild-type NUP98, but also exhibited similar transcriptional properties as RARA fusions found in acute promyelocytic leukemia (APL). Using murine bone marrow retroviral transduction/transformation assay, we further demonstrated that NUP98-RARG fusion protein had gained transformation ability of primary hematopoietic stem/progenitor cells, which was critically dependent on the C-terminal GLFG domain of NUP98 and the DNA binding domain (DBD) of RARG. In contrast to other NUP98 fusions, cells transformed by the NUP98-RARG fusion were extremely sensitive to all-trans retinoic acid (ATRA) treatment. Interestingly, while pan-RXR agonists, SR11237 and LGD1069 could specifically inhibit NUP98-RARG transformed cells, mutation of the RXR interaction domain in NUP98-RARG had little effect on its transformation, revealing that therapeutic functions of rexinoid can be independent of the direct biochemical interaction between RXR and the fusion. Together, these results indicate that deregulation of the retinoid/rexinoid signaling pathway has a major role and may represent a potential therapeutic target for NUP98-RARG-mediated transformation.
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Affiliation(s)
- J J Qiu
- 1] Department of Medicine, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA [2] Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, PA, USA
| | - B B Zeisig
- King's College London, Leukaemia and Stem Cell Biology Group, Department of Haematologial Medicine, London UK
| | - S Li
- 1] Department of Medicine, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA [2] Department of Oncology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - W Liu
- Department of Oncology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - H Chu
- Department of Medicine, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Y Song
- Department of Pharmacology, Baylor College of Medicine, Houston, TX, USA
| | - A Giordano
- 1] Sbarro Institute for Cancer Research and Molecular Medicine & Center for Biotechology, Temple University, Philadelphia, PA, USA [2] Department of Medicine, Surgery & Neuroscience, University of Siena, Siena, Italy
| | - J Schwaller
- University Children's Hospital Basel (UKBB), Department of Biomedicine, Hebelstrasse 20, CH-4031 Basel, Switzerland
| | - H Gronemeyer
- Equipe Labellisée Ligue Contre le Cancer, Department of Functional Genomics and Cancer, Institut Génétique de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/UdS/CERBM, C.U. de Strasbourg, BP 10142, Illkirch-Cedex, France
| | - S Dong
- Department of Medicine, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - C W E So
- King's College London, Leukaemia and Stem Cell Biology Group, Department of Haematologial Medicine, London UK
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Morchoisne-Bolhy S, Geoffroy MC, Bouhlel IB, Alves A, Audugé N, Baudin X, Van Bortle K, Powers MA, Doye V. Intranuclear dynamics of the Nup107-160 complex. Mol Biol Cell 2015; 26:2343-56. [PMID: 25904327 PMCID: PMC4462950 DOI: 10.1091/mbc.e15-02-0060] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/14/2015] [Indexed: 12/11/2022] Open
Abstract
The Nup107-160 nuclear pore subcomplex (Y-complex) and the chromatin-binding nucleoporin Elys dynamically colocalize with Nup98 and the export factor CRM1 in nuclear GLFG bodies present in HeLa sublines. Thus, in addition to its structural role at the NPC and its mitotic functions, the Y-complex may also act inside the nucleus during interphase. Nup98 is a glycine-leucine-phenylalanine-glycine (GLFG) repeat–containing nucleoporin that, in addition to nuclear transport, contributes to multiple aspects of gene regulation. Previous studies revealed its dynamic localization within intranuclear structures known as GLFG bodies. Here we show that the mammalian Nup107-160 complex (Y-complex), a major scaffold module of the nuclear pore, together with its partner Elys, colocalizes with Nup98 in GLFG bodies. The frequency and size of GLFG bodies vary among HeLa sublines, and we find that an increased level of Nup98 is associated with the presence of bodies. Recruitment of the Y-complex and Elys into GLFG bodies requires the C-terminal domain of Nup98. During cell division, Y-Nup–containing GLFG bodies are disassembled in mitotic prophase, significantly ahead of nuclear pore disassembly. FRAP studies revealed that, unlike at nuclear pores, the Y-complex shuttles into and out of GLFG bodies. Finally, we show that within the nucleoplasm, a fraction of Nup107, a key component of the Y-complex, displays reduced mobility, suggesting interaction with other nuclear components. Together our data uncover a previously neglected intranuclear pool of the Y-complex that may underscore a yet-uncharacterized function of these nucleoporins inside the nucleus, even in cells that contain no detectable GLFG bodies.
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Affiliation(s)
| | - Marie-Claude Geoffroy
- Institut Jacques Monod, CNRS UMR7592-Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Imène B Bouhlel
- Institut Jacques Monod, CNRS UMR7592-Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Annabelle Alves
- Institut Jacques Monod, CNRS UMR7592-Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France Ecole Doctorale Gènes Génomes Cellules, Université Paris Sud, 91405 Orsay, France
| | - Nicolas Audugé
- Institut Jacques Monod, CNRS UMR7592-Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Xavier Baudin
- ImagoSeine Imaging Facility, Institut Jacques Monod, 75205 Paris, France
| | - Kevin Van Bortle
- Department of Cell Biology and Biochemistry, Cell and Developmental Biology Graduate Program, Emory University School of Medicine, Atlanta, GA 30322
| | - Maureen A Powers
- Department of Cell Biology and Biochemistry, Cell and Developmental Biology Graduate Program, Emory University School of Medicine, Atlanta, GA 30322
| | - Valérie Doye
- Institut Jacques Monod, CNRS UMR7592-Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
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Schertzer M, Jouravleva K, Perderiset M, Dingli F, Loew D, Le Guen T, Bardoni B, de Villartay JP, Revy P, Londoño-Vallejo A. Human regulator of telomere elongation helicase 1 (RTEL1) is required for the nuclear and cytoplasmic trafficking of pre-U2 RNA. Nucleic Acids Res 2015; 43:1834-47. [PMID: 25628358 PMCID: PMC4330364 DOI: 10.1093/nar/gku1402] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Hoyeraal-Hreidarsson syndrome (HHS) is a severe form of Dyskeratosis congenita characterized by developmental defects, bone marrow failure and immunodeficiency and has been associated with telomere dysfunction. Recently, mutations in Regulator of Telomere ELongation helicase 1 (RTEL1), a helicase first identified in Mus musculus as being responsible for the maintenance of long telomeres, have been identified in several HHS patients. Here we show that RTEL1 is required for the export and the correct cytoplasmic trafficking of the small nuclear (sn) RNA pre-U2, a component of the major spliceosome complex. RTEL1-HHS cells show abnormal subcellular partitioning of pre-U2, defects in the recycling of ribonucleotide proteins (RNP) in the cytoplasm and splicing defects. While most of these phenotypes can be suppressed by re-expressing the wild-type protein in RTEL1-HHS cells, expression of RTEL1 mutated variants in immortalized cells provokes cytoplasmic mislocalizations of pre-U2 and other RNP components, as well as splicing defects, thus phenocopying RTEL1-HHS cellular defects. Strikingly, expression of a cytoplasmic form of RTEL1 is sufficient to correct RNP mislocalizations both in RTEL1-HHS cells and in cells expressing nuclear mutated forms of RTEL1. This work unravels completely unanticipated roles for RTEL1 in RNP trafficking and strongly suggests that defects in RNP biogenesis pathways contribute to the pathology of HHS.
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Affiliation(s)
- Michael Schertzer
- Telomeres & Cancer laboratory, CNRS, 'Labellisé Ligue', Institut Curie, 26 rue d'Ulm, Paris 75248, France Sorbonne Universités, Paris 06, Paris F-75005, France PSL Research University, Paris, France
| | - Karina Jouravleva
- Telomeres & Cancer laboratory, CNRS, 'Labellisé Ligue', Institut Curie, 26 rue d'Ulm, Paris 75248, France Sorbonne Universités, Paris 06, Paris F-75005, France PSL Research University, Paris, France
| | - Mylene Perderiset
- Telomeres & Cancer laboratory, CNRS, 'Labellisé Ligue', Institut Curie, 26 rue d'Ulm, Paris 75248, France Sorbonne Universités, Paris 06, Paris F-75005, France PSL Research University, Paris, France
| | - Florent Dingli
- Laboratory of Proteomic Mass Spectrometry, Institut Curie, Paris, France
| | - Damarys Loew
- Laboratory of Proteomic Mass Spectrometry, Institut Curie, Paris, France
| | - Tangui Le Guen
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Paris, France Université Sorbonne Paris Cité, Université Paris Descartes, Institut Imagine, Paris, France
| | - Barbara Bardoni
- IPMC-CNRS UMR7275-Valbonne, France Université de Nice Sophia-Antipolis, Nice 06560, France
| | - Jean-Pierre de Villartay
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Paris, France Université Sorbonne Paris Cité, Université Paris Descartes, Institut Imagine, Paris, France
| | - Patrick Revy
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Paris, France Université Sorbonne Paris Cité, Université Paris Descartes, Institut Imagine, Paris, France
| | - Arturo Londoño-Vallejo
- Telomeres & Cancer laboratory, CNRS, 'Labellisé Ligue', Institut Curie, 26 rue d'Ulm, Paris 75248, France Sorbonne Universités, Paris 06, Paris F-75005, France PSL Research University, Paris, France
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Fung HYJ, Chook YM. Atomic basis of CRM1-cargo recognition, release and inhibition. Semin Cancer Biol 2014; 27:52-61. [PMID: 24631835 PMCID: PMC4108548 DOI: 10.1016/j.semcancer.2014.03.002] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/01/2014] [Indexed: 11/19/2022]
Abstract
CRM1 or XPO1 is the major nuclear export receptor in the cell, which controls the nuclear-cytoplasmic localization of many proteins and RNAs. CRM1 is also a promising cancer drug target as the transport receptor is overexpressed in many cancers where some of its cargos are misregulated and mislocalized to the cytoplasm. Atomic level understanding of CRM1 function has greatly facilitated recent drug discovery and development of CRM1 inhibitors to target a variety of malignancies. Numerous atomic resolution CRM1 structures are now available, explaining how the exporter recognizes nuclear export signals in its cargos, how RanGTP and cargo bind with positive cooperativity, how RanBP1 causes release of export cargos in the cytoplasm and how diverse inhibitors such as Leptomycin B and the new KPT-SINE compounds block nuclear export. This review summarizes structure-function studies that explain CRM1-cargo recognition, release and inhibition.
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Affiliation(s)
- Ho Yee Joyce Fung
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park, Dallas, TX 75390-9041, USA.
| | - Yuh Min Chook
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park, Dallas, TX 75390-9041, USA.
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40
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Oridonin induces NPM mutant protein translocation and apoptosis in NPM1c+ acute myeloid leukemia cells in vitro. Acta Pharmacol Sin 2014; 35:806-13. [PMID: 24902788 DOI: 10.1038/aps.2014.25] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 03/24/2014] [Indexed: 12/24/2022] Open
Abstract
AIM Skewed cytoplasmic accumulation of NPM mutant protein (NPM1c+) is close related to leukemia pathogenesis. The aim of this study was to investigate whether oridonin, a diterpenoid isolated from the Chinese traditional medicine Rabdosia rubescens, was able to interfere with NPM1c+ protein trafficking and induce apoptosis in NPM1c+ acute myeloid leukemia cells in vitro. METHODS OCI-AML3 cell line harboring a NPM1 gene mutation was examined. Cell growth was detected by MTT assay. Cell apoptosis was evaluated using flow cytometry and Hoechst 33258 staining. The expression and subcellular localization of relevant proteins were detected by Western blot and immunofluorescent staining. The mRNA expression was detected by RT-PCR. RESULTS Oridonin (2-12 μmol/L) dose-dependently inhibited the viability of OCI-AML3 cells (the IC50 value was 3.27±0.23 μmol/L at 24 h). Moreover, oridonin induced OCI-AML3 cell apoptosis accompanied by activation of caspase-3 and nuclear translocation of NPM1c+ protein. Oridonin did not change the expression of Crm1 (the export receptor for nuclear export signal-containing proteins), but induced nuclear translocation of Crm1. Oridonin markedly increased the expression of nucleoporin98 (Nup98), which had an important role in Crm1-mediated nuclear protein export, and induced nuclear accumulation of Nup98. Furthermore, oridonin markedly increased the expression of p14arf and p53. CONCLUSION In NPM1c+ leukemia cells, oridonin induces NPM1c+ protein translocation into the nucleus possibly via nuclear accumulation of Crm1; the compound markedly increases p53 and p14arf expression, which may contribute to cell apoptosis.
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Abstract
Nuclear pore complexes (NPCs) are the sole gateways between the nucleus and the cytoplasm of eukaryotic cells and they mediate all macromolecular trafficking between these cellular compartments. Nucleocytoplasmic transport is highly selective and precisely regulated and as such an important aspect of normal cellular function. Defects in this process or in its machinery have been linked to various human diseases, including cancer. Nucleoporins, which are about 30 proteins that built up NPCs, are critical players in nucleocytoplasmic transport and have also been shown to be key players in numerous other cellular processes, such as cell cycle control and gene expression regulation. This review will focus on the three nucleoporins Nup98, Nup214, and Nup358. Common to them is their significance in nucleocytoplasmic transport, their multiple other functions, and being targets for chromosomal translocations that lead to haematopoietic malignancies, in particular acute myeloid leukaemia. The underlying molecular mechanisms of nucleoporin-associated leukaemias are only poorly understood but share some characteristics and are distinguished by their poor prognosis and therapy outcome.
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Takeda A, Yaseen NR. Nucleoporins and nucleocytoplasmic transport in hematologic malignancies. Semin Cancer Biol 2014; 27:3-10. [PMID: 24657637 DOI: 10.1016/j.semcancer.2014.02.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 02/21/2014] [Indexed: 11/19/2022]
Abstract
Hematologic malignancies are often associated with chromosomal rearrangements that lead to the expression of chimeric fusion proteins. Rearrangements of the genes encoding two nucleoporins, NUP98 and NUP214, have been implicated in the pathogenesis of several types of hematologic malignancies, particularly acute myeloid leukemia. NUP98 rearrangements result in fusion of an N-terminal portion of NUP98 to one of numerous proteins. These rearrangements often follow treatment with topoisomerase II inhibitors and tend to occur in younger patients. They have been shown to induce leukemia in mice and to enhance proliferation and disrupt differentiation in primary human hematopoietic precursors. NUP214 has only a few fusion partners. DEK-NUP214 is the most common NUP214 fusion in AML; it tends to occur in younger patients and is usually associated with FLT3 internal tandem duplications. The leukemogenic activity of NUP214 fusions is less well characterized. Normal nucleoporins, including NUP98 and NUP214, have important functions in nucleocytoplasmic transport, transcription, and mitosis. These functions and their disruptions by oncogenic nucleoporin fusions are discussed.
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Affiliation(s)
- Akiko Takeda
- Department of Pathology and Immunology, Washington University in St. Louis, United States.
| | - Nabeel R Yaseen
- Department of Pathology and Immunology, Washington University in St. Louis, United States.
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Dian C, Bernaudat F, Langer K, Oliva MF, Fornerod M, Schoehn G, Müller CW, Petosa C. Structure of a truncation mutant of the nuclear export factor CRM1 provides insights into the auto-inhibitory role of its C-terminal helix. Structure 2013; 21:1338-49. [PMID: 23850454 DOI: 10.1016/j.str.2013.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 06/12/2013] [Accepted: 06/13/2013] [Indexed: 11/23/2022]
Abstract
Chromosome region maintenance 1/exportin1/Xpo1 (CRM1) associates with the GTPase Ran to mediate the nuclear export of proteins bearing a leucine-rich nuclear export signal (NES). CRM1 consists of helical hairpin HEAT repeats and a C-terminal helical extension (C-extension) that inhibits the binding of NES-bearing cargos. We report the crystal structure and small-angle X-ray scattering analysis of a human CRM1 mutant with enhanced NES-binding activity due to deletion of the C-extension. We show that loss of the C-extension leads to a repositioning of CRM1's C-terminal repeats and to a more extended overall conformation. Normal mode analysis predicts reduced rigidity for the deletion mutant, consistent with an observed decrease in thermal stability. Point mutations that destabilize the C-extension shift CRM1 to the more extended conformation, reduce thermal stability, and enhance NES-binding activity. These findings suggest that an important mechanism by which the C-extension regulates CRM1's cargo-binding affinity is by modulating the conformation and flexibility of its HEAT repeats.
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Affiliation(s)
- Cyril Dian
- Université de Grenoble Alpes, Institut de Biologie Structurale, 38027 Grenoble, France
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Kuss SK, Mata MA, Zhang L, Fontoura BMA. Nuclear imprisonment: viral strategies to arrest host mRNA nuclear export. Viruses 2013; 5:1824-49. [PMID: 23872491 PMCID: PMC3738964 DOI: 10.3390/v5071824] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 06/27/2013] [Accepted: 07/11/2013] [Indexed: 12/15/2022] Open
Abstract
Viruses possess many strategies to impair host cellular responses to infection. Nuclear export of host messenger RNAs (mRNA) that encode antiviral factors is critical for antiviral protein production and control of viral infections. Several viruses have evolved sophisticated strategies to inhibit nuclear export of host mRNAs, including targeting mRNA export factors and nucleoporins to compromise their roles in nucleo-cytoplasmic trafficking of cellular mRNA. Here, we present a review of research focused on suppression of host mRNA nuclear export by viruses, including influenza A virus and vesicular stomatitis virus, and the impact of this viral suppression on host antiviral responses.
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Affiliation(s)
- Sharon K Kuss
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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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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Yoshimura SH, Otsuka S, Kumeta M, Taga M, Takeyasu K. Intermolecular disulfide bonds between nucleoporins regulate karyopherin-dependent nuclear transport. J Cell Sci 2013; 126:3141-50. [PMID: 23641069 DOI: 10.1242/jcs.124172] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Disulfide (S-S) bonds play important roles in the regulation of protein function and cellular stress responses. In this study, we demonstrate that distinct sets of nucleoporins (Nups), components of the nuclear pore complex (NPC), form S-S bonds and regulate nuclear transport through the NPC. Kinetic analysis of importin β demonstrated that the permeability of the NPC was increased by dithiothreitol treatment and reduced by oxidative stress. The permeability of small proteins such as GFP was not affected by either oxidative stress or a reducing reagent. Immunoblot analysis revealed that the oxidative stress significantly induced S-S bond formation in Nups 358, 155, 153 and 62 but not 88 and 160. The direct involvement of cysteine residues in the formation of S-S bonds was confirmed by mutating conserved cysteine residues in Nup62, which abolished the formation of S-S bonds and enhanced the permeability of the NPC. Knocking down Nup62 reduced the stress-inducible S-S bonds of Nup155, suggesting that Nup62 and Nup155 are covalently coupled via S-S bonds. From these results, we propose that the inner channel of the NPC is somehow insulated from the cytoplasm and is more sensitive than the cytoplasm to the intracellular redox state.
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Affiliation(s)
- Shige H Yoshimura
- Graduate School of Biostudies, Kyoto University, Yoshida-konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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Natalizio BJ, Wente SR. Postage for the messenger: designating routes for nuclear mRNA export. Trends Cell Biol 2013; 23:365-73. [PMID: 23583578 DOI: 10.1016/j.tcb.2013.03.006] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/12/2013] [Accepted: 03/14/2013] [Indexed: 01/22/2023]
Abstract
Transcription of mRNA occurs in the nucleus, making the translocation of mRNA across the nuclear envelope (NE) boundary a critical determinant of proper gene expression and cell survival. A major mRNA export route occurs via the NXF1-dependent pathway through the nuclear pore complexes (NPCs) embedded in the NE. However, recent findings have discovered new evidence supporting the existence of multiple mechanisms for crossing the NE, including both NPC-mediated and NE budding-mediated pathways. An analysis of the trans-acting factors and cis components that define these pathways reveals shared elements as well as mechanistic differences. We review here the current understanding of the mechanisms that characterize each pathway and highlight the determinants that influence mRNA transport fate.
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Affiliation(s)
- Barbara J Natalizio
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37323, USA
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Thakar K, Karaca S, Port SA, Urlaub H, Kehlenbach RH. Identification of CRM1-dependent Nuclear Export Cargos Using Quantitative Mass Spectrometry. Mol Cell Proteomics 2013; 12:664-78. [PMID: 23242554 PMCID: PMC3591659 DOI: 10.1074/mcp.m112.024877] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 11/23/2012] [Indexed: 11/06/2022] Open
Abstract
Chromosome region maintenance 1/exportin1/Exp1/Xpo1 (CRM1) is the major transport receptor for the export of proteins from the nucleus. It binds to nuclear export signals (NESs) that are rich in leucines and other hydrophobic amino acids. The prediction of NESs is difficult because of the extreme recognition flexibility of CRM1. Furthermore, proteins can be exported upon binding to an NES-containing adaptor protein. Here we present an approach for identifying targets of the CRM1-export pathway via quantitative mass spectrometry using stable isotope labeling with amino acids in cell culture. With this approach, we identified >100 proteins from HeLa cells that were depleted from cytosolic fractions and/or enriched in nuclear fractions in the presence of the selective CRM1-inhibitor leptomycin B. Novel and validated substrates are the polyubiquitin-binding protein sequestosome 1, the cancerous inhibitor of protein phosphatase 2A (PP2A), the guanine nucleotide-binding protein-like 3-like protein, the programmed cell death protein 2-like protein, and the cytosolic carboxypeptidase 1 (CCP1). We identified a functional NES in CCP1 that mediates direct binding to the export receptor CRM1. The method will be applicable to other nucleocytoplasmic transport pathways, as well as to the analysis of nucleocytoplasmic shuttling proteins under different growth conditions.
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Affiliation(s)
- Ketan Thakar
- From the ‡Department of Biochemistry I, Faculty of Medicine, Georg-August-University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Samir Karaca
- ¶Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Sarah A. Port
- From the ‡Department of Biochemistry I, Faculty of Medicine, Georg-August-University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Henning Urlaub
- ¶Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
- ‖Bioanalytics, Department of Clinical Chemistry, University Medical Center, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Ralph H. Kehlenbach
- From the ‡Department of Biochemistry I, Faculty of Medicine, Georg-August-University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
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49
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Abstract
Budding yeast, like other eukaryotes, carries its genetic information on chromosomes that are sequestered from other cellular constituents by a double membrane, which forms the nucleus. An elaborate molecular machinery forms large pores that span the double membrane and regulate the traffic of macromolecules into and out of the nucleus. In multicellular eukaryotes, an intermediate filament meshwork formed of lamin proteins bridges from pore to pore and helps the nucleus reform after mitosis. Yeast, however, lacks lamins, and the nuclear envelope is not disrupted during yeast mitosis. The mitotic spindle nucleates from the nucleoplasmic face of the spindle pole body, which is embedded in the nuclear envelope. Surprisingly, the kinetochores remain attached to short microtubules throughout interphase, influencing the position of centromeres in the interphase nucleus, and telomeres are found clustered in foci at the nuclear periphery. In addition to this chromosomal organization, the yeast nucleus is functionally compartmentalized to allow efficient gene expression, repression, RNA processing, genomic replication, and repair. The formation of functional subcompartments is achieved in the nucleus without intranuclear membranes and depends instead on sequence elements, protein-protein interactions, specific anchorage sites at the nuclear envelope or at pores, and long-range contacts between specific chromosomal loci, such as telomeres. Here we review the spatial organization of the budding yeast nucleus, the proteins involved in forming nuclear subcompartments, and evidence suggesting that the spatial organization of the nucleus is important for nuclear function.
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The role of Nup98 in transcription regulation in healthy and diseased cells. Trends Cell Biol 2012; 23:112-7. [PMID: 23246429 DOI: 10.1016/j.tcb.2012.10.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 10/26/2012] [Accepted: 10/31/2012] [Indexed: 02/07/2023]
Abstract
Nuclear pore complex (NPC) proteins are known for their critical roles in regulating nucleocytoplasmic traffic of macromolecules across the nuclear envelope. However, recent findings suggest that some nucleoporins (Nups), including Nup98, have additional functions in developmental gene regulation. Nup98, which exhibits transcription-dependent mobility at the NPC but can also bind chromatin away from the nuclear envelope, is frequently involved in chromosomal translocations in a subset of patients suffering from acute myeloid leukemia (AML). A common paradigm suggests that Nup98 translocations cause aberrant transcription when they are recuited to aberrant genomic loci. Importantly, this model fails to account for the potential loss of wild type (WT) Nup98 function in the presence of Nup98 translocation mutants. Here we examine how the cell might regulate Nup98 nucleoplasmic protein levels to control transcription in healthy cells. In addition, we discuss the possibility that dominant negative Nup98 fusion proteins disrupt the transcriptional activity of WT Nup98 in the nucleoplasm to drive AML.
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