51
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Van Bergen NJ, Bell KM, Carey K, Gear R, Massey S, Murrell EK, Gallacher L, Pope K, Lockhart PJ, Kornberg A, Pais L, Walkiewicz M, Simons C, Wickramasinghe VO, White SM, Christodoulou J. Pathogenic variants in nucleoporin TPR (translocated promoter region, nuclear basket protein) cause severe intellectual disability in humans. Hum Mol Genet 2021; 31:362-375. [PMID: 34494102 DOI: 10.1093/hmg/ddab248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 08/10/2021] [Accepted: 08/23/2021] [Indexed: 01/16/2023] Open
Abstract
The nuclear pore complex (NPC) is a multi-protein complex that regulates the trafficking of macromolecules between the nucleus and cytoplasm. Genetic variants in components of the NPC have been shown to cause a range of neurological disorders, including intellectual disability and microcephaly. Translocated promoter region, nuclear basket protein (TPR) is a critical scaffolding element of the nuclear facing interior of the NPC. Here we present two siblings with biallelic variants in TPR who present with a phenotype of microcephaly, ataxia and severe intellectual disability. The variants result in a premature truncation variant, and a splice variant leading to a 12-amino acid deletion respectively. Functional analyses in patient fibroblasts demonstrate significantly reduced TPR levels, and decreased TPR-containing NPC density. A compensatory increase in total NPC levels was observed, and decreased global RNA intensity in the nucleus. The discovery of variants that partly disable TPR function provide valuable insight into this essential protein in human disease, and our findings suggest that TPR variants are the cause of the siblings' neurological disorder.
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Affiliation(s)
- Nicole J Van Bergen
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Katrina M Bell
- Bioinformatics, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia.,Victorian Clinical Genetics Services, Royal Children's Hospital, VIC, Australia
| | - Kirsty Carey
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Russell Gear
- Victorian Clinical Genetics Services, Royal Children's Hospital, VIC, Australia
| | - Sean Massey
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | - Edward K Murrell
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | - Lyndon Gallacher
- Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Victorian Clinical Genetics Services, Royal Children's Hospital, VIC, Australia
| | - Kate Pope
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | - Paul J Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | - Andrew Kornberg
- Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Neurology Department, Royal Children's Hospital, Melbourne, Australia.,Neurosciences Research, Murdoch Children's Research Institute, Victoria, Australia
| | - Lynn Pais
- Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Marzena Walkiewicz
- Translational Genomics Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | - Cas Simons
- Victorian Clinical Genetics Services, Royal Children's Hospital, VIC, Australia.,Translational Genomics Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia
| | | | - Vihandha O Wickramasinghe
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Susan M White
- Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Victorian Clinical Genetics Services, Royal Children's Hospital, VIC, Australia
| | - John Christodoulou
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Discipline of Child & Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
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52
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Arginine-rich dipeptide-repeat proteins as phase disruptors in C9-ALS/FTD. Emerg Top Life Sci 2021; 4:293-305. [PMID: 32639008 DOI: 10.1042/etls20190167] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/15/2020] [Accepted: 06/17/2020] [Indexed: 12/11/2022]
Abstract
A hexanucleotide repeat expansion GGGGCC (G4C2) within chromosome 9 open reading frame 72 (C9orf72) is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). This seminal realization has rapidly focused our attention to the non-canonical translation (RAN translation) of the repeat expansion, which yields dipeptide-repeat protein products (DPRs). The mechanisms by which DPRs might contribute to C9-ALS/FTD are widely studied. Arginine-rich DPRs (R-DPRs) are the most toxic of the five different DPRs produced in neurons, but how do R-DPRs promote C9-ALS/FTD pathogenesis? Proteomic analyses have uncovered potential pathways to explore. For example, the vast majority of the R-DPR interactome is comprised of disease-linked RNA-binding proteins (RBPs) with low-complexity domains (LCDs), strongly suggesting a link between R-DPRs and aberrations in liquid-liquid phase separation (LLPS). In this review, we showcase several potential mechanisms by which R-DPRs disrupt various phase-separated compartments to elicit deleterious neurodegeneration. We also discuss potential therapeutic strategies to counter R-DPR toxicity in C9-ALS/FTD.
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53
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Coyne AN, Baskerville V, Zaepfel BL, Dickson DW, Rigo F, Bennett F, Lusk CP, Rothstein JD. Nuclear accumulation of CHMP7 initiates nuclear pore complex injury and subsequent TDP-43 dysfunction in sporadic and familial ALS. Sci Transl Med 2021; 13:eabe1923. [PMID: 34321318 PMCID: PMC9022198 DOI: 10.1126/scitranslmed.abe1923] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 03/02/2021] [Accepted: 06/09/2021] [Indexed: 01/29/2023]
Abstract
Alterations in the components [nucleoporins (Nups)] and function of the nuclear pore complex (NPC) have been implicated as contributors to the pathogenesis of genetic forms of neurodegeneration including C9orf72 amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD). We hypothesized that Nup alterations and the consequential loss of NPC function may lie upstream of TDP-43 dysfunction and mislocalization widely observed in ALS, FTD, and related neurodegenerative diseases. Here, we provide evidence that CHMP7, a critical mediator of NPC quality control, is increased in nuclei of C9orf72 and sporadic ALS induced pluripotent stem cell (iPSC)-derived spinal neurons (iPSNs) and postmortem human motor cortex before the emergence of Nup alterations. Inhibiting the nuclear export of CHMP7 triggered Nup reduction and TDP-43 dysfunction and pathology in human neurons. Knockdown of CHMP7 alleviated disease-associated Nup alterations, deficits in Ran GTPase localization, defects in TDP-43-associated mRNA expression, and downstream glutamate-induced neuronal death. Thus, our data support a role for altered CHMP7-mediated Nup homeostasis as a prominent initiating pathological mechanism for familial and sporadic ALS and highlight the potential for CHMP7 as therapeutic target.
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Affiliation(s)
- Alyssa N Coyne
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Victoria Baskerville
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Benjamin L Zaepfel
- Biochemistry, Cellular, and Molecular Biology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92010, USA
| | | | - C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Jeffrey D Rothstein
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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54
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Panagaki D, Croft JT, Keuenhof K, Larsson Berglund L, Andersson S, Kohler V, Büttner S, Tamás MJ, Nyström T, Neutze R, Höög JL. Nuclear envelope budding is a response to cellular stress. Proc Natl Acad Sci U S A 2021; 118:e2020997118. [PMID: 34290138 PMCID: PMC8325156 DOI: 10.1073/pnas.2020997118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nuclear envelope budding (NEB) is a recently discovered alternative pathway for nucleocytoplasmic communication distinct from the movement of material through the nuclear pore complex. Through quantitative electron microscopy and tomography, we demonstrate how NEB is evolutionarily conserved from early protists to human cells. In the yeast Saccharomyces cerevisiae, NEB events occur with higher frequency during heat shock, upon exposure to arsenite or hydrogen peroxide, and when the proteasome is inhibited. Yeast cells treated with azetidine-2-carboxylic acid, a proline analog that induces protein misfolding, display the most dramatic increase in NEB, suggesting a causal link to protein quality control. This link was further supported by both localization of ubiquitin and Hsp104 to protein aggregates and NEB events, and the evolution of these structures during heat shock. We hypothesize that NEB is part of normal cellular physiology in a vast range of species and that in S. cerevisiae NEB comprises a stress response aiding the transport of protein aggregates across the nuclear envelope.
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Affiliation(s)
- Dimitra Panagaki
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Jacob T Croft
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Katharina Keuenhof
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Lisa Larsson Berglund
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Stefanie Andersson
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Verena Kohler
- Department of Molecular Bioscienses, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Sabrina Büttner
- Department of Molecular Bioscienses, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Markus J Tamás
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Thomas Nyström
- Department of Microbiology and Immunology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Richard Neutze
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Johanna L Höög
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Gothenburg, Sweden;
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55
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Hoogenboom BW, Hough LE, Lemke EA, Lim RYH, Onck PR, Zilman A. Physics of the Nuclear Pore Complex: Theory, Modeling and Experiment. PHYSICS REPORTS 2021; 921:1-53. [PMID: 35892075 PMCID: PMC9306291 DOI: 10.1016/j.physrep.2021.03.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The hallmark of eukaryotic cells is the nucleus that contains the genome, enclosed by a physical barrier known as the nuclear envelope (NE). On the one hand, this compartmentalization endows the eukaryotic cells with high regulatory complexity and flexibility. On the other hand, it poses a tremendous logistic and energetic problem of transporting millions of molecules per second across the nuclear envelope, to facilitate their biological function in all compartments of the cell. Therefore, eukaryotes have evolved a molecular "nanomachine" known as the Nuclear Pore Complex (NPC). Embedded in the nuclear envelope, NPCs control and regulate all the bi-directional transport between the cell nucleus and the cytoplasm. NPCs combine high molecular specificity of transport with high throughput and speed, and are highly robust with respect to molecular noise and structural perturbations. Remarkably, the functional mechanisms of NPC transport are highly conserved among eukaryotes, from yeast to humans, despite significant differences in the molecular components among various species. The NPC is the largest macromolecular complex in the cell. Yet, despite its significant complexity, it has become clear that its principles of operation can be largely understood based on fundamental physical concepts, as have emerged from a combination of experimental methods of molecular cell biology, biophysics, nanoscience and theoretical and computational modeling. Indeed, many aspects of NPC function can be recapitulated in artificial mimics with a drastically reduced complexity compared to biological pores. We review the current physical understanding of the NPC architecture and function, with the focus on the critical analysis of experimental studies in cells and artificial NPC mimics through the lens of theoretical and computational models. We also discuss the connections between the emerging concepts of NPC operation and other areas of biophysics and bionanotechnology.
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Affiliation(s)
- Bart W. Hoogenboom
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - Loren E. Hough
- Department of Physics and BioFrontiers Institute, University of Colorado, Boulder CO 80309, United States of America
| | - Edward A. Lemke
- Biocenter Mainz, Departments of Biology and Chemistry, Johannes Gutenberg University and Institute of Molecular Biology, 55128 Mainz, Germany
| | - Roderick Y. H. Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Patrick R. Onck
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Anton Zilman
- Department of Physics and Institute for Biomedical Engineering (IBME), University of Toronto, Toronto, ON M5S 1A7, Canada
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56
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Shen Q, Wang YE, Palazzo AF. Crosstalk between nucleocytoplasmic trafficking and the innate immune response to viral infection. J Biol Chem 2021; 297:100856. [PMID: 34097873 PMCID: PMC8254040 DOI: 10.1016/j.jbc.2021.100856] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 05/24/2021] [Accepted: 06/03/2021] [Indexed: 12/16/2022] Open
Abstract
The nuclear pore complex is the sole gateway connecting the nucleoplasm and cytoplasm. In humans, the nuclear pore complex is one of the largest multiprotein assemblies in the cell, with a molecular mass of ∼110 MDa and consisting of 8 to 64 copies of about 34 different nuclear pore proteins, termed nucleoporins, for a total of 1000 subunits per pore. Trafficking events across the nuclear pore are mediated by nuclear transport receptors and are highly regulated. The nuclear pore complex is also used by several RNA viruses and almost all DNA viruses to access the host cell nucleoplasm for replication. Viruses hijack the nuclear pore complex, and nuclear transport receptors, to access the nucleoplasm where they replicate. In addition, the nuclear pore complex is used by the cell innate immune system, a network of signal transduction pathways that coordinates the first response to foreign invaders, including viruses and other pathogens. Several branches of this response depend on dynamic signaling events that involve the nuclear translocation of downstream signal transducers. Mounting evidence has shown that these signaling cascades, especially those steps that involve nucleocytoplasmic trafficking events, are targeted by viruses so that they can evade the innate immune system. This review summarizes how nuclear pore proteins and nuclear transport receptors contribute to the innate immune response and highlights how viruses manipulate this cellular machinery to favor infection. A comprehensive understanding of nuclear pore proteins in antiviral innate immunity will likely contribute to the development of new antiviral therapeutic strategies.
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Affiliation(s)
- Qingtang Shen
- School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.
| | - Yifan E Wang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Alexander F Palazzo
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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57
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Orti F, Navarro AM, Rabinovich A, Wodak SJ, Marino-Buslje C. Insight into membraneless organelles and their associated proteins: Drivers, Clients and Regulators. Comput Struct Biotechnol J 2021; 19:3964-3977. [PMID: 34377363 PMCID: PMC8318826 DOI: 10.1016/j.csbj.2021.06.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/26/2021] [Accepted: 06/27/2021] [Indexed: 02/06/2023] Open
Abstract
In recent years, attention has been devoted to proteins forming immiscible liquid phases within the liquid intracellular medium, commonly referred to as membraneless organelles (MLO). These organelles enable the spatiotemporal associations of cellular components that exchange dynamically with the cellular milieu. The dysregulation of these liquid-liquid phase separation processes (LLPS) may cause various diseases including neurodegenerative pathologies and cancer, among others. Until very recently, databases containing information on proteins forming MLOs, as well as tools and resources facilitating their analysis, were missing. This has recently changed with the publication of 4 databases that focus on different types of experiments, sets of proteins, inclusion criteria, and levels of annotation or curation. In this study we integrate and analyze the information across these databases, complement their records, and produce a consolidated set of proteins that enables the investigation of the LLPS phenomenon. To gain insight into the features that characterize different types of MLOs and the roles of their associated proteins, they were grouped into categories: High Confidence MLO associated (including Drivers and reviewed proteins), Potential Clients and Regulators, according to their annotated functions. We show that none of the databases taken alone covers the data sufficiently to enable meaningful analysis, validating our integration effort as essential for gaining better understanding of phase separation and laying the foundations for the discovery of new proteins potentially involved in this important cellular process. Lastly, we developed a server, enabling customized selections of different sets of proteins based on MLO location, database, disorder content, among other attributes (https://forti.shinyapps.io/mlos/).
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Affiliation(s)
- Fernando Orti
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
| | - Alvaro M. Navarro
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
| | - Andres Rabinovich
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
| | - Shoshana J. Wodak
- VIB-VUB Center for Structural Biology, Flemish Institute for Biotechnology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Cristina Marino-Buslje
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
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58
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TNPO1-Mediated Nuclear Import of FUBP1 Contributes to Tumor Immune Evasion by Increasing NRP1 Expression in Cervical Cancer. J Immunol Res 2021; 2021:9994004. [PMID: 33987449 PMCID: PMC8093035 DOI: 10.1155/2021/9994004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/14/2021] [Accepted: 04/15/2021] [Indexed: 11/25/2022] Open
Abstract
Far upstream element binding protein 1 (FUBP1), a DNA-binding protein, participates in diverse tumor-promoting behaviors by regulating the expression of oncogenes in the nucleus, but the underlying mechanisms remain to be elucidated. In the present study, we found that FUBP1 mRNA and protein expressions were markedly upregulated and closely linked with poor prognosis in cervical cancer. In vitro, functional experiments showed that knockdown of FUBP1 inhibited CC cell proliferation and migration. Therefore, FUBP1 plays a prooncogenic function in CC progression. Further investigations for the first time demonstrated that nuclear localization of FUBP1 regulated the gene expression of immune checkpoint NRP1. Moreover, our work demonstrated that FUBP1 translocated into the nucleus which was mediated by interacting with Transportin-1 (TNPO1). Collectively, this study revealed that FUBP1 might be a potential therapeutic target for the restriction of tumor progression.
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59
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Azmi AS, Uddin MH, Mohammad RM. The nuclear export protein XPO1 - from biology to targeted therapy. Nat Rev Clin Oncol 2021; 18:152-169. [PMID: 33173198 DOI: 10.1038/s41571-020-00442-4] [Citation(s) in RCA: 116] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2020] [Indexed: 12/23/2022]
Abstract
Exportin 1 (XPO1), also known as chromosome region maintenance protein 1, plays a crucial role in maintaining cellular homeostasis via the regulated export of a range of cargoes, including proteins and several classes of RNAs, from the nucleus to the cytoplasm. Dysregulation of this protein plays a pivotal role in the development of various solid and haematological malignancies. Furthermore, XPO1 is associated with resistance to several standard-of-care therapies, including chemotherapies and targeted therapies, making it an attractive target of novel cancer therapies. Over the years, a number of selective inhibitors of nuclear export have been developed. However, only selinexor has been clinically validated. The novel mechanism of action of XPO1 inhibitors implies a different toxicity profile to that of other agents and has proved challenging in certain settings. Nonetheless, data from clinical trials have led to the approval of the XPO1 inhibitor selinexor (plus dexamethasone) as a fifth-line therapy for patients with multiple myeloma and as a monotherapy for patients with relapsed and/or refractory diffuse large B cell lymphoma. In this Review, we summarize the progress and challenges in the development of nuclear export inhibitors and discuss the potential of emerging combination therapies and biomarkers of response.
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MESH Headings
- Antineoplastic Agents/therapeutic use
- Cell Line, Tumor
- Dexamethasone/therapeutic use
- Drug Resistance, Neoplasm/genetics
- Hematologic Neoplasms/drug therapy
- Hematologic Neoplasms/genetics
- Hematologic Neoplasms/pathology
- Humans
- Hydrazines/therapeutic use
- Karyopherins/antagonists & inhibitors
- Karyopherins/genetics
- Lymphoma, Large B-Cell, Diffuse/drug therapy
- Lymphoma, Large B-Cell, Diffuse/genetics
- Lymphoma, Large B-Cell, Diffuse/pathology
- Molecular Targeted Therapy
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, Cytoplasmic and Nuclear/genetics
- Triazoles/therapeutic use
- Exportin 1 Protein
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Affiliation(s)
- Asfar S Azmi
- Karmanos Cancer Institute, Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Mohammed H Uddin
- Karmanos Cancer Institute, Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Ramzi M Mohammad
- Karmanos Cancer Institute, Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA.
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60
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Shen Q, Wang YE, Truong M, Mahadevan K, Wu JJ, Zhang H, Li J, Smith HW, Smibert CA, Palazzo AF. RanBP2/Nup358 enhances miRNA activity by sumoylating Argonautes. PLoS Genet 2021; 17:e1009378. [PMID: 33600493 PMCID: PMC7924746 DOI: 10.1371/journal.pgen.1009378] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 03/02/2021] [Accepted: 01/25/2021] [Indexed: 02/07/2023] Open
Abstract
Mutations in RanBP2 (also known as Nup358), one of the main components of the cytoplasmic filaments of the nuclear pore complex, contribute to the overproduction of acute necrotizing encephalopathy (ANE1)-associated cytokines. Here we report that RanBP2 represses the translation of the interleukin 6 (IL6) mRNA, which encodes a cytokine that is aberrantly up-regulated in ANE1. Our data indicates that soon after its production, the IL6 messenger ribonucleoprotein (mRNP) recruits Argonautes bound to let-7 microRNA. After this mRNP is exported to the cytosol, RanBP2 sumoylates mRNP-associated Argonautes, thereby stabilizing them and enforcing mRNA silencing. Collectively, these results support a model whereby RanBP2 promotes an mRNP remodelling event that is critical for the miRNA-mediated suppression of clinically relevant mRNAs, such as IL6.
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Affiliation(s)
- Qingtang Shen
- School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, China
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Yifan E. Wang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Mathew Truong
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Kohila Mahadevan
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jingze J. Wu
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Hui Zhang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jiawei Li
- School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, China
| | - Harrison W. Smith
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Craig A. Smibert
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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61
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Rivera AA, Aballay-González A, Gonçalves AT, Tarifeño E, Ulloa V, Gallardo JJ, Astuya-Villalón A. Search for potential biomarkers for saxitoxin detection. Toxicol In Vitro 2021; 72:105092. [PMID: 33440187 DOI: 10.1016/j.tiv.2021.105092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/19/2020] [Accepted: 01/07/2021] [Indexed: 11/18/2022]
Abstract
The Neuro-2a cell assay has been a promising in vitro alternative for the detection of saxitoxin (STX)-like toxins. However, its application is problematic in samples with complex matrices containing different toxins, whose mechanisms of action could be antagonistic. In the search of alternative procedures that reduce or avoid this interference, we evaluated the transcriptional modulation produced by a 24-h exposure to STX in Neuro-2a cells under three conditions: exposure to STX (33 nM), a mussel meat matrix (12.5 mg meat/mL) and a fortified sample (STX-fortified matrix). Differential gene expression was evaluated by RNA-seq after Illumina high-throughput sequencing, and data were analyzed to identify genes differentially expressed regardless of the matrix. From the 9487 identified genes, 213 were differentially expressed of these, 10 genes were identified as candidate markers for STX detection due to their regulation by STX regardless of the matrix interference. Expression dynamics of 7 of these candidate genes (Fgf-1, Adgrb2, Tfpt, Zfr2, Nup 35, Fam195a, and Dusp7) was further evaluated by qRT-PCR analysis of cells exposed to different concentrations of STX for up to 24 h. A downregulation of some markers expression was observed, namely Nup35 (involved in nucleo-cytoplasmic transporter activity) and Zfr-2 (involved in nucleic acids binding), whereas Fgf-1 (apoptosis signaling) was significantly upregulated. Markers' expression was not influenced by the matrix, suggesting that gene expression variations are directly related to STX response. These results support the potential of these genes as biomarkers for the development of an alternative STX-like toxins screening method.
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Affiliation(s)
- Alejandra A Rivera
- Centro de Investigación Oceanográfica COPAS Sur-Austral, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile; Laboratorio de Biotoxinas de la Universidad de Concepción (LBTx-UdeC), Facultad de Ciencias Naturales y Oceanografía, Departamento de Oceanografía, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile
| | - Ambbar Aballay-González
- Laboratorio de Biotoxinas de la Universidad de Concepción (LBTx-UdeC), Facultad de Ciencias Naturales y Oceanografía, Departamento de Oceanografía, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile
| | - Ana Teresa Gonçalves
- Interdisciplinary Center for Aquaculture Research, INCAR, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile
| | - Estefanía Tarifeño
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile
| | - Viviana Ulloa
- Laboratorio de Biotoxinas de la Universidad de Concepción (LBTx-UdeC), Facultad de Ciencias Naturales y Oceanografía, Departamento de Oceanografía, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile
| | - Juan José Gallardo
- Departamento de Ingeniería Química, Escuela Superior de Ingeniería, Universidad de Almería, Carretera Sacramento, Calle San Urbano s/n, La Cañada, Almería, Spain
| | - Allisson Astuya-Villalón
- Centro de Investigación Oceanográfica COPAS Sur-Austral, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile; Laboratorio de Biotoxinas de la Universidad de Concepción (LBTx-UdeC), Facultad de Ciencias Naturales y Oceanografía, Departamento de Oceanografía, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile.
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Meng W, Gao SJ. Targeting XPO1 enhances innate immune response and inhibits KSHV lytic replication during primary infection by nuclear stabilization of the p62 autophagy adaptor protein. Cell Death Dis 2021; 12:29. [PMID: 33414399 PMCID: PMC7790339 DOI: 10.1038/s41419-020-03303-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/27/2020] [Accepted: 12/02/2020] [Indexed: 12/15/2022]
Abstract
Nucleocytoplasmic transport of signaling modulators is essential for regulating cellular responses to extracellular stimulation and stress, as well as pathogen infection. Exportin 1 (XPO1), also known as chromosomal maintenance 1 (CRM1), mediates nuclear export of proteins, rRNAs, snRNAs, and some mRNAs. In this study, we have identified an essential role of XPO1 in regulating Kaposi's sarcoma-associated herpesvirus (KSHV) lytic replication during primary infection of primary human umbilical vein endothelial cells. Treatment with an XPO1 inhibitor KPT-8602 and short hairpin RNA (shRNA)-mediated knockdown of XPO1 reduced KSHV lytic replication but had no effect on KSHV entry and trafficking. XPO1 inhibition induced retention of autophagy adaptor protein p62 (SQSTM1) in the nucleus, which enhanced activation of TBK1 and IRF3. As a result, nuclear accumulation of p62 increased expression of innate immune-related genes including IRF7, ISG15, IFIT1, IFIT2, and IFIT3, leading to a reduction of KSHV lytic replication. These results illustrate a novel mechanism by which XPO1 mediates innate immune response and KSHV replication, and identify XPO1 as a potential therapeutic target and KPT-8602 as a promising therapeutic agent for KSHV infection.
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Affiliation(s)
- Wen Meng
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shou-Jiang Gao
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA.
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63
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Goto C, Hara-Nishimura I, Tamura K. Regulation and Physiological Significance of the Nuclear Shape in Plants. FRONTIERS IN PLANT SCIENCE 2021; 12:673905. [PMID: 34177991 PMCID: PMC8222917 DOI: 10.3389/fpls.2021.673905] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 05/14/2021] [Indexed: 05/19/2023]
Abstract
The shape of plant nuclei varies among different species, tissues, and cell types. In Arabidopsis thaliana seedlings, nuclei in meristems and guard cells are nearly spherical, whereas those of epidermal cells in differentiated tissues are elongated spindle-shaped. The vegetative nuclei in pollen grains are irregularly shaped in angiosperms. In the past few decades, it has been revealed that several nuclear envelope (NE) proteins play the main role in the regulation of the nuclear shape in plants. Some plant NE proteins that regulate nuclear shape are also involved in nuclear or cellular functions, such as nuclear migration, maintenance of chromatin structure, gene expression, calcium and reactive oxygen species signaling, plant growth, reproduction, and plant immunity. The shape of the nucleus has been assessed both by labeling internal components (for instance chromatin) and by labeling membranes, including the NE or endoplasmic reticulum in interphase cells and viral-infected cells of plants. Changes in NE are correlated with the formation of invaginations of the NE, collectively called the nucleoplasmic reticulum. In this review, what is known and what is unknown about nuclear shape determination are presented, and the physiological significance of the control of the nuclear shape in plants is discussed.
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Affiliation(s)
- Chieko Goto
- Graduate School of Science, Kobe University, Kobe, Japan
| | | | - Kentaro Tamura
- School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
- *Correspondence: Kentaro Tamura,
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64
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Bishop J, Swan H, Valente F, Nützmann HW. The Plant Nuclear Envelope and Its Role in Gene Transcription. FRONTIERS IN PLANT SCIENCE 2021; 12:674209. [PMID: 33995467 PMCID: PMC8119737 DOI: 10.3389/fpls.2021.674209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 03/25/2021] [Indexed: 05/12/2023]
Abstract
Chromosomes are dynamic entities in the eukaryotic nucleus. During cell development and in response to biotic and abiotic change, individual sections as well as entire chromosomes re-organise and reposition within the nuclear space. A focal point for these processes is the nuclear envelope (NE) providing both barrier and anchor for chromosomal movement. In plants, positioning of chromosome regions and individual genes at the nuclear envelope has been shown to be associated with distinct transcriptional patterns. Here, we will review recent findings on the interplay between transcriptional activity and gene positioning at the nuclear periphery (NP). We will discuss potential mechanisms of transcriptional regulation at the nuclear envelope and outline future perspectives in this research area.
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65
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Pulupa J, Prior H, Johnson DS, Simon SM. Conformation of the nuclear pore in living cells is modulated by transport state. eLife 2020; 9:e60654. [PMID: 33346731 PMCID: PMC7752133 DOI: 10.7554/elife.60654] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/23/2020] [Indexed: 12/15/2022] Open
Abstract
While the static structure of the nuclear pore complex (NPC) continues to be refined with cryo-EM and x-ray crystallography, in vivo conformational changes of the NPC remain under-explored. We developed sensors that report on the orientation of NPC components by rigidly conjugating mEGFP to different NPC proteins. Our studies show conformational changes to select domains of nucleoporins (Nups) within the inner ring (Nup54, Nup58, Nup62) when transport through the NPC is perturbed and no conformational changes to Nups elsewhere in the NPC. Our results suggest that select components of the NPC are flexible and undergo conformational changes upon engaging with cargo.
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Affiliation(s)
- Joan Pulupa
- Laboratory of Cellular Biophysics, Rockefeller UniversityNew YorkUnited States
| | - Harriet Prior
- Laboratory of Cellular Biophysics, Rockefeller UniversityNew YorkUnited States
| | - Daniel S Johnson
- Department of Physics and Astronomy, Hofstra UniversityHempsteadUnited States
| | - Sanford M Simon
- Laboratory of Cellular Biophysics, Rockefeller UniversityNew YorkUnited States
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66
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Muller R, Meacham ZA, Ferguson L, Ingolia NT. CiBER-seq dissects genetic networks by quantitative CRISPRi profiling of expression phenotypes. Science 2020; 370:eabb9662. [PMID: 33303588 PMCID: PMC7819735 DOI: 10.1126/science.abb9662] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 10/22/2020] [Indexed: 12/12/2022]
Abstract
To realize the promise of CRISPR-Cas9-based genetics, approaches are needed to quantify a specific, molecular phenotype across genome-wide libraries of genetic perturbations. We addressed this challenge by profiling transcriptional, translational, and posttranslational reporters using CRISPR interference (CRISPRi) with barcoded expression reporter sequencing (CiBER-seq). Our barcoding approach allowed us to connect an entire library of guides to their individual phenotypic consequences using pooled sequencing. CiBER-seq profiling fully recapitulated the integrated stress response (ISR) pathway in yeast. Genetic perturbations causing uncharged transfer RNA (tRNA) accumulation activated ISR reporter transcription. Notably, tRNA insufficiency also activated the reporter, independent of the uncharged tRNA sensor. By uncovering alternate triggers for ISR activation, we illustrate how precise, comprehensive CiBER-seq profiling provides a powerful and broadly applicable tool for dissecting genetic networks.
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Affiliation(s)
- Ryan Muller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Zuriah A Meacham
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Lucas Ferguson
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Nicholas T Ingolia
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
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67
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Persi E, Wolf YI, Horn D, Ruppin E, Demichelis F, Gatenby RA, Gillies RJ, Koonin EV. Mutation-selection balance and compensatory mechanisms in tumour evolution. Nat Rev Genet 2020; 22:251-262. [PMID: 33257848 DOI: 10.1038/s41576-020-00299-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2020] [Indexed: 12/11/2022]
Abstract
Intratumour heterogeneity and phenotypic plasticity, sustained by a range of somatic aberrations, as well as epigenetic and metabolic adaptations, are the principal mechanisms that enable cancers to resist treatment and survive under environmental stress. A comprehensive picture of the interplay between different somatic aberrations, from point mutations to whole-genome duplications, in tumour initiation and progression is lacking. We posit that different genomic aberrations generally exhibit a temporal order, shaped by a balance between the levels of mutations and selective pressures. Repeat instability emerges first, followed by larger aberrations, with compensatory effects leading to robust tumour fitness maintained throughout the tumour progression. A better understanding of the interplay between genetic aberrations, the microenvironment, and epigenetic and metabolic cellular states is essential for early detection and prevention of cancer as well as development of efficient therapeutic strategies.
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Affiliation(s)
- Erez Persi
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA.
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - David Horn
- School of Physics and Astronomy, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Eytan Ruppin
- Cancer Data Science Lab, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Francesca Demichelis
- Department for Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy.,Caryl and Israel Englander Institute for Precision Medicine, New York Presbyterian Hospital, Weill Cornell Medicine, New York, NY, USA
| | - Robert A Gatenby
- Integrated Mathematical Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Robert J Gillies
- Department of Cancer Physiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA.
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA.
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68
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Martin APJ, Camonis JH. The hippo kinase STK38 ensures functionality of XPO1. Cell Cycle 2020; 19:2982-2995. [PMID: 33017560 PMCID: PMC7714482 DOI: 10.1080/15384101.2020.1826619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 08/06/2020] [Accepted: 08/08/2020] [Indexed: 10/23/2022] Open
Abstract
The proper segregation of basic elements such as the compartmentalization of the genome and the shuttling of macromolecules between the nucleus and the cytoplasm is a crucial mechanism for homeostasis maintenance in eukaryotic cells. XPO1 (Exportin 1) is the major nuclear export receptor and is required for the export of proteins and RNAs out of the nucleus. STK38 (also known as NDR1) is a Hippo pathway serine/threonine kinase with multifarious functions in normal and cancer cells. In this review, we summarize the history of the discovery of the nucleo/cytoplasmic shuttling of proteins and focus on the major actor of nuclear export: XPO1. After describing the molecular events required for XPO1-mediated nuclear export of proteins, we introduce the Hippo pathway STK38 kinase, synthetize its regulation mechanisms as well as its biological functions in both normal and cancer cells, and finally its intersection with XPO1 biology. We discuss the recently identified mechanism of XPO1 activation by phosphorylation of XPO1_S1055 by STK38 and contextualize this finding according to the biological functions previously reported for both XPO1 and STK38, including the second identity of STK38 as an autophagy regulator. Finally, we phrase this newly identified activation mechanism into the general nuclear export machinery and examine the possible outcomes of nuclear export inhibition in cancer treatment.
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Affiliation(s)
- Alexandre PJ Martin
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, USA
| | - Jacques H Camonis
- Inserm U830, Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University, Paris, France
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69
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Identification of AR-V7 downstream genes commonly targeted by AR/AR-V7 and specifically targeted by AR-V7 in castration resistant prostate cancer. Transl Oncol 2020; 14:100915. [PMID: 33096335 PMCID: PMC7581977 DOI: 10.1016/j.tranon.2020.100915] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/28/2020] [Accepted: 10/12/2020] [Indexed: 12/20/2022] Open
Abstract
The entire landscape of AR-V7 target regions/genes in CRPC cells was investigated. We identified 78 AR-V7 target genes, targeted specifically by AR-V7 e.g. SLC3A2, or commonly by AR and AR-V7 e.g. NUP210. SLC3A2 and NUP210 were markedly upregulated in clinical CRPC tissues, leading to increased proliferation in CRPC.
Primary prostate cancer (PC) progresses to castration-resistant PC (CRPC) under androgen deprivation therapy, by mechanisms e.g. expression of androgen receptor (AR) splice variant-7 (AR-V7). Here we conducted comprehensive epigenome and transcriptome analyses comparing LNCaP, primary PC cells, and LNCaP95, AR-V7-expressing CRPC cells derived from LNCaP. Of 399 AR-V7 target regions identified through ChIP-seq analysis, 377 could be commonly targeted by hormone-stimulated AR, and 22 were specifically targeted by AR-V7. Among genes neighboring to these AR-V7 target regions, 78 genes were highly expressed in LNCaP95, while AR-V7 knockdown led to significant repression of these genes and suppression of growth of LNCaP95. Of the 78 AR-V7 target genes, 74 were common AR/AR-V7 target genes and 4 were specific AR-V7 target genes; their most suppressed genes by AR-V7 knockdown were NUP210 and SLC3A2, respectively, and underwent subsequent analyses. NUP210 and SLC3A2 were significantly upregulated in clinical CRPC tissues, and their knockdown resulted in significant suppression of cellular growth of LNCaP95 through apoptosis and growth arrest. Collectively, AR-V7 contributes to CRPC proliferation by activating both common AR/AR-V7 target and specific AR-V7 target, e.g. NUP210 and SLC3A2.
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70
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Östlund C, Hernandez-Ono A, Shin JY. The Nuclear Envelope in Lipid Metabolism and Pathogenesis of NAFLD. BIOLOGY 2020; 9:biology9100338. [PMID: 33076344 PMCID: PMC7602593 DOI: 10.3390/biology9100338] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023]
Abstract
Simple Summary The liver is a major organ regulating lipid metabolism and a proper liver function is essential to health. Nonalcoholic fatty liver disease (NAFLD) is a condition with abnormal fat accumulation in the liver without heavy alcohol use. NAFLD is becoming one of the most common liver diseases with the increase in obesity in many parts of the world. There is no approved cure for the disease and a better understanding of disease mechanism is needed for effective prevention and treatment. The nuclear envelope, a membranous structure that surrounds the cell nucleus, is connected to the endoplasmic reticulum where the vast majority of cellular lipids are synthesized. Growing evidence indicates that components in the nuclear envelope are involved in cellular lipid metabolism. We review published studies with various cell and animal models, indicating the essential roles of nuclear envelope proteins in lipid metabolism. We also discuss how defects in these proteins affect cellular lipid metabolism and possibly contribute to the pathogenesis of NAFLD. Abstract Nonalcoholic fatty liver disease (NAFLD) is a burgeoning public health problem worldwide. Despite its tremendous significance for public health, we lack a comprehensive understanding of the pathogenic mechanisms of NAFLD and its more advanced stage, nonalcoholic steatohepatitis (NASH). Identification of novel pathways or cellular mechanisms that regulate liver lipid metabolism has profound implications for the understanding of the pathology of NAFLD and NASH. The nuclear envelope is topologically connected to the ER, where protein synthesis and lipid synthesis occurs. Emerging evidence points toward that the nuclear lamins and nuclear membrane-associated proteins are involved in lipid metabolism and homeostasis. We review published reports that link these nuclear envelope proteins to lipid metabolism. In particular, we focus on the recent work demonstrating the essential roles for the nuclear envelope-localized torsinA/lamina-associated polypeptide (LAP1) complex in hepatic steatosis, lipid secretion, and NASH development. We also discuss plausible pathogenic mechanisms by which the loss of either protein in hepatocytes leads to hepatic dyslipidemia and NASH development.
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Affiliation(s)
- Cecilia Östlund
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (C.Ö.); (A.H.-O.)
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Antonio Hernandez-Ono
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (C.Ö.); (A.H.-O.)
| | - Ji-Yeon Shin
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; (C.Ö.); (A.H.-O.)
- Correspondence: ; Tel.: +1-212-305-4088
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71
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Theoretical Modeling of Chemical Equilibrium in Weak Polyelectrolyte Layers on Curved Nanosystems. Polymers (Basel) 2020; 12:polym12102282. [PMID: 33027995 PMCID: PMC7601300 DOI: 10.3390/polym12102282] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022] Open
Abstract
Surface functionalization with end-tethered weak polyelectrolytes (PE) is a versatile way to modify and control surface properties, given their ability to alter their degree of charge depending on external cues like pH and salt concentration. Weak PEs find usage in a wide range of applications, from colloidal stabilization, lubrication, adhesion, wetting to biomedical applications such as drug delivery and theranostics applications. They are also ubiquitous in many biological systems. Here, we present an overview of some of the main theoretical methods that we consider key in the field of weak PE at interfaces. Several applications involving engineered nanoparticles, synthetic and biological nanopores, as well as biological macromolecules are discussed to illustrate the salient features of systems involving weak PE near an interface or under (nano)confinement. The key feature is that by confining weak PEs near an interface the degree of charge is different from what would be expected in solution. This is the result of the strong coupling between structural organization of weak PE and its chemical state. The responsiveness of engineered and biological nanomaterials comprising weak PE combined with an adequate level of modeling can provide the keys to a rational design of smart nanosystems.
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72
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Mateu-Regué À, Christiansen J, Bagger FO, Winther O, Hellriegel C, Nielsen FC. Single mRNP Analysis Reveals that Small Cytoplasmic mRNP Granules Represent mRNA Singletons. Cell Rep 2020; 29:736-748.e4. [PMID: 31618640 DOI: 10.1016/j.celrep.2019.09.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 10/19/2018] [Accepted: 09/06/2019] [Indexed: 12/24/2022] Open
Abstract
Small cytoplasmic mRNP granules are implicated in mRNA transport, translational control, and decay. Using super-resolution microscopy and fluorescence correlation spectroscopy, we analyzed the molecular composition and dynamics of single cytoplasmic YBX1_IMP1 mRNP granules in live cells. Granules appeared elongated and branched, with patches of IMP1 and YBX1 distributed along mRNA, reflecting the attachment of the two RNA-binding proteins in cis. Particles form at the nuclear pore and do not associate with translating ribosomes, so the mRNP is a repository for mRNAs awaiting translation. In agreement with the average number of mRNA-binding sites derived from crosslinked immunoprecipitation (CLIP) analyses, individual mRNPs contain 5-15 molecules of YBX1 and IMP1 and a single poly(A) tail identified by PABPC1. Taken together, we conclude that small cytoplasmic mRNP granules are mRNA singletons, thus depicting the cellular transcriptome. Consequently, expression of functionally related mRNAs in RNA regulons is unlikely to result from coordinated assembly.
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Affiliation(s)
- Àngels Mateu-Regué
- Center for Genomic Medicine, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Jan Christiansen
- Department of Biology, Copenhagen Biocenter, Ole Maaloes Vej 5, 2200 Copenhagen, Denmark
| | - Frederik Otzen Bagger
- Center for Genomic Medicine, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Ole Winther
- Center for Genomic Medicine, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Christian Hellriegel
- Carl Zeiss RMS, Harvard Center for Biological Imaging, 16 Divinity Avenue, Cambridge, MA 02138, USA
| | - Finn Cilius Nielsen
- Center for Genomic Medicine, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark.
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73
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Modeling the nucleoporins that form the hairy pores. Biochem Soc Trans 2020; 48:1447-1461. [DOI: 10.1042/bst20190941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 07/03/2020] [Accepted: 07/16/2020] [Indexed: 11/17/2022]
Abstract
Sitting on the nuclear envelope, nuclear pore complexes (NPCs) control the molecular transport between the nucleus and the cytoplasm. Without definite open or close states, the NPC uses a family of intrinsically disordered nucleoporins called FG-Nups to construct a selective permeability barrier whose functional structure is unclear. Experimental advances have offered high-resolution molecular knowledge of the NPC scaffold and docking of the unfolded FG-Nups, however, the ‘hairy’ barrier structure still appears as blurred lobes even under the state-of-the-art microscopy. Without accurate experimental visualization, the molecular mechanism for the NPC-mediated transport remains a matter of debate. Modeling provides an alternative way to resolve this long-standing mystery. Here, we briefly review different methods employed in modeling the FG-Nups, arranging from all-atom molecular dynamics to mean-field theories. We discuss the advantage and limit of each modeling technique, and summarize the theoretical insights that, despite certain controversy, deepened our understanding of the hairy pore.
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74
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Tessier TM, MacNeil KM, Mymryk JS. Piggybacking on Classical Import and Other Non-Classical Mechanisms of Nuclear Import Appear Highly Prevalent within the Human Proteome. BIOLOGY 2020; 9:biology9080188. [PMID: 32718019 PMCID: PMC7463951 DOI: 10.3390/biology9080188] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 12/23/2022]
Abstract
One of the most conserved cellular pathways among eukaryotes is the extensively studied classical protein nuclear import pathway mediated by importin-α. Classical nuclear localization signals (cNLSs) are recognized by importin-α and are highly predictable due to their abundance of basic amino acids. However, various studies in model organisms have repeatedly demonstrated that only a fraction of nuclear proteins contain identifiable cNLSs, including those that directly interact with importin-α. Using data from the Human Protein Atlas and the Human Reference Interactome, and proteomic data from BioID/protein-proximity labeling studies using multiple human importin-α proteins, we determine that nearly 50% of the human nuclear proteome does not have a predictable cNLS. Surprisingly, between 25% and 50% of previously identified human importin-α cargoes do not have predictable cNLS. Analysis of importin-α cargo without a cNLS identified an alternative basic rich motif that does not resemble a cNLS. Furthermore, several previously suspected piggybacking proteins were identified, such as those belonging to the RNA polymerase II and transcription factor II D complexes. Additionally, many components of the mediator complex interact with at least one importin-α, yet do not have a predictable cNLS, suggesting that many of the subunits may enter the nucleus through an importin-α-dependent piggybacking mechanism.
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Affiliation(s)
- Tanner M. Tessier
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON N6A 3K7, Canada; (T.M.T.); (K.M.M.)
| | - Katelyn M. MacNeil
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON N6A 3K7, Canada; (T.M.T.); (K.M.M.)
| | - Joe S. Mymryk
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON N6A 3K7, Canada; (T.M.T.); (K.M.M.)
- Department of Otolaryngology, Head & Neck Surgery, The University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Oncology, The University of Western Ontario, London, ON N6A 3K7, Canada
- London Regional Cancer Program, Lawson Health Research Institute, London, ON N6A 5W9, Canada
- Correspondence: ; Tel.: +1-519-685-8600 (ext. 53012)
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75
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Francia ME, Bhavsar S, Ting LM, Croken MM, Kim K, Dubremetz JF, Striepen B. A Homolog of Structural Maintenance of Chromosome 1 Is a Persistent Centromeric Protein Which Associates With Nuclear Pore Components in Toxoplasma gondii. Front Cell Infect Microbiol 2020; 10:295. [PMID: 32714878 PMCID: PMC7343853 DOI: 10.3389/fcimb.2020.00295] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/19/2020] [Indexed: 01/02/2023] Open
Abstract
Apicomplexa are obligate intracellular parasites which cause various animal and human diseases including malaria, toxoplasmosis, and cryptosporidiosis. They proliferate by a unique mechanism that combines physically separated semi-closed mitosis of the nucleus and assembly of daughter cells by internal budding. Mitosis occurs in the presence of a nuclear envelope and with little appreciable chromatin condensation. A long standing question in the field has been how parasites keep track of their uncondensed chromatin chromosomes throughout their development, and hence secure proper chromosome segregation during division. Past work demonstrated that the centromeres, the region of kinetochore assembly at chromosomes, of Toxoplasma gondii remain clustered at a defined region of the nuclear periphery proximal to the main microtubule organizing center of the cell, the centrosome. We have proposed that this mechanism is likely involved in the process. Here we set out to identify underlying molecular players involved in centromere clustering. Through pharmacological treatment and structural analysis we show that centromere clustering is not mediated by persistent microtubules of the mitotic spindle. We identify the chromatin binding factor a homolog of structural maintenance of chromosomes 1 (SMC1). Additionally, we show that both TgSMC1, and a centromeric histone, interact with TgExportin1, a predicted soluble component of the nuclear pore complex. Our results suggest that the nuclear envelope, and in particular the nuclear pore complex may play a role in positioning centromeres in T. gondii.
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Affiliation(s)
- Maria E Francia
- Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Sheila Bhavsar
- Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Li-Min Ting
- Morsani College of Medicine, University of South Florida Health, Tampa, FL, United States
| | - Matthew M Croken
- Pathology, Molecular and Cell Based Medicine, Mount Sinai Medical Center, New York, NY, United States
| | - Kami Kim
- Morsani College of Medicine, University of South Florida Health, Tampa, FL, United States
| | | | - Boris Striepen
- Department of Cellular Biology, University of Georgia, Athens, GA, United States.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
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76
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Zhang Y, Li S, Zeng C, Huang G, Zhu X, Wang Q, Wang K, Zhou Q, Yan C, Zhang W, Yang G, Liu M, Tao Q, Lei J, Shi Y. Molecular architecture of the luminal ring of the Xenopus laevis nuclear pore complex. Cell Res 2020; 30:532-540. [PMID: 32367042 PMCID: PMC7264284 DOI: 10.1038/s41422-020-0320-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 04/06/2020] [Indexed: 12/23/2022] Open
Abstract
The nuclear pore complex (NPC) mediates the flow of substances between the nucleus and cytoplasm in eukaryotic cells. Here we report the cryo-electron tomography (cryo-ET) structure of the luminal ring (LR) of the NPC from Xenopus laevis oocyte. The observed key structural features of the LR are independently confirmed by single-particle cryo-electron microscopy (cryo-EM) analysis. The LR comprises eight butterfly-shaped subunits, each containing two symmetric wings. Each wing consists of four elongated, tubular protomers. Within the LR subunit, the eight protomers form a Finger domain, which directly contacts the fusion between the inner and outer nuclear membranes and a Grid domain, which serves as a rigid base for the Finger domain. Two neighboring LR subunits interact with each other through the lateral edges of their wings to constitute a Bumper domain, which displays two major conformations and appears to cushion neighboring NPCs. Our study reveals previously unknown features of the LR and potentially explains the elastic property of the NPC.
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Affiliation(s)
- Yanqing Zhang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
| | - Sai Li
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Chao Zeng
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Gaoxingyu Huang
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xuechen Zhu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
| | - Qifan Wang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
| | - Kunpeng Wang
- Tsinghua Computing Facility & Department of Computer Science, Tsinghua University, Beijing, 100084, China
| | - Qiang Zhou
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
| | - Chuangye Yan
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Wusheng Zhang
- Tsinghua Computing Facility & Department of Computer Science, Tsinghua University, Beijing, 100084, China
| | - Guangwen Yang
- Tsinghua Computing Facility & Department of Computer Science, Tsinghua University, Beijing, 100084, China
| | - Minhao Liu
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Qinghua Tao
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jianlin Lei
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yigong Shi
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China.
- Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China.
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Tsinghua University-Peking University Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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77
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Bishop PJ, Kinoshita Y, Lopes NN, Ward AS, Kohtz DS. Changes in Nup62 content affect contact-induced differentiation of cultured myoblasts. Differentiation 2020; 114:27-35. [PMID: 32554220 DOI: 10.1016/j.diff.2020.05.001] [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: 10/01/2019] [Revised: 03/21/2020] [Accepted: 05/11/2020] [Indexed: 10/24/2022]
Abstract
Differentiation of cultured skeletal myoblasts is induced by extrinsic signals that include reduction in ambient mitogen concentration and increased cell density. Using an established murine myoblast cell line (C2C12), we have found that experimental reduction of the nucleoporin p62 (Nup62) content of myoblasts enhances differentiation in high-mitogen medium, while forced expression of Nup62 inhibits density-induced differentiation. In contrast, differentiation of myoblasts induced by low-mitogen medium was unaffected by ectopic Nup62 expression. Further analyses suggested that Nup62 content affects density-induced myoblast differentiation through a mechanism involving activation of p38 MAP kinase. Nuclear pore complex (NPC) composition, in particular changes in NUP62 content, may be altered during viral infection, differentiation, and in neoplastic growth. The results support a functional role for changes in Nup62 composition in NPCs and density-induced myogenic differentiation, and suggest a link between loss of Nup62 content and induction of an intracellular stress signaling pathways.
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Affiliation(s)
- Patrick J Bishop
- Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, MI, 48859, USA.
| | - Yayoi Kinoshita
- Department of Pathology, Icahn School of Medicine, One Gustave Levy Place, New York, NY, 10029, USA.
| | - N Natalie Lopes
- Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, MI, 48859, USA.
| | - Avery S Ward
- Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, MI, 48859, USA.
| | - D Stave Kohtz
- Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, MI, 48859, USA.
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78
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Structure of the cytoplasmic ring of the Xenopus laevis nuclear pore complex by cryo-electron microscopy single particle analysis. Cell Res 2020; 30:520-531. [PMID: 32376910 PMCID: PMC7264146 DOI: 10.1038/s41422-020-0319-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 04/06/2020] [Indexed: 12/20/2022] Open
Abstract
The nuclear pore complex (NPC) exhibits structural plasticity and has only been characterized at local resolutions of up to 15 Å for the cytoplasmic ring (CR). Here we present a single-particle cryo-electron microscopy (cryo-EM) structure of the CR from Xenopus laevis NPC at average resolutions of 5.5–7.9 Å, with local resolutions reaching 4.5 Å. Improved resolutions allow identification and placement of secondary structural elements in the majority of the CR components. The two Y complexes in each CR subunit interact with each other and associate with those from flanking subunits, forming a circular scaffold. Within each CR subunit, the Nup358-containing region wraps around the stems of both Y complexes, likely stabilizing the scaffold. Nup205 connects the short arms of the two Y complexes and associates with the stem of a neighboring Y complex. The Nup214-containing region uses an extended coiled-coil to link Nup85 of the two Y complexes and protrudes into the axial pore of the NPC. These previously uncharacterized structural features reveal insights into NPC assembly.
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79
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Maxwell PH. Diverse transposable element landscapes in pathogenic and nonpathogenic yeast models: the value of a comparative perspective. Mob DNA 2020; 11:16. [PMID: 32336995 PMCID: PMC7175516 DOI: 10.1186/s13100-020-00215-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/16/2020] [Indexed: 12/14/2022] Open
Abstract
Genomics and other large-scale analyses have drawn increasing attention to the potential impacts of transposable elements (TEs) on their host genomes. However, it remains challenging to transition from identifying potential roles to clearly demonstrating the level of impact TEs have on genome evolution and possible functions that they contribute to their host organisms. I summarize TE content and distribution in four well-characterized yeast model systems in this review: the pathogens Candida albicans and Cryptococcus neoformans, and the nonpathogenic species Saccharomyces cerevisiae and Schizosaccharomyces pombe. I compare and contrast their TE landscapes to their lifecycles, genomic features, as well as the presence and nature of RNA interference pathways in each species to highlight the valuable diversity represented by these models for functional studies of TEs. I then review the regulation and impacts of the Ty1 and Ty3 retrotransposons from Saccharomyces cerevisiae and Tf1 and Tf2 retrotransposons from Schizosaccharomyces pombe to emphasize parallels and distinctions between these well-studied elements. I propose that further characterization of TEs in the pathogenic yeasts would enable this set of four yeast species to become an excellent set of models for comparative functional studies to address outstanding questions about TE-host relationships.
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80
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Poot M. Mutated NUP188 and Other Nucleoporins as Gateways to Developmental Syndromes. Mol Syndromol 2020; 11:1-3. [PMID: 32256295 DOI: 10.1159/000506410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2020] [Indexed: 11/19/2022] Open
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81
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Khan AU, Qu R, Ouyang J, Dai J. Role of Nucleoporins and Transport Receptors in Cell Differentiation. Front Physiol 2020; 11:239. [PMID: 32308628 PMCID: PMC7145948 DOI: 10.3389/fphys.2020.00239] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 03/02/2020] [Indexed: 12/20/2022] Open
Abstract
Bidirectional molecular movements between the nucleus and cytoplasm take place through nuclear pore complexes (NPCs) embedded in the nuclear membrane. These macromolecular structures are composed of several nucleoporins, which form seven different subcomplexes based on their biochemical affinity. These nucleoporins are integral components of the complex, not only allowing passive transport but also interacting with importin, exportin, and other molecules that are required for transport of protein in various cellular processes. Transport of different proteins is carried out either dependently or independently on transport receptors. As well as facilitating nucleocytoplasmic transport, nucleoporins also play an important role in cell differentiation, possibly by their direct gene interaction. This review will cover the general role of nucleoporins (whether its dependent or independent) and nucleocytoplasmic transport receptors in cell differentiation.
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82
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Şenbaş Akyazi B, Pirinçal A, Kawaguchi A, Nagata K, Turan K. Interaction of influenza A virus NS2/NEP protein with the amino-terminal part of Nup214. ACTA ACUST UNITED AC 2020; 44:82-92. [PMID: 32256144 PMCID: PMC7129063 DOI: 10.3906/biy-1909-49] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Influenza A viruses have a single-stranded RNA genome consisting of 8 segments. Each RNA segment associates with the nucleoprotein (NP) and viral RNA polymerase to and from a viral ribonucleoprotein (vRNP) particle. The viral mRNA synthesis is dependent on a capped primer derived from nascent host RNA transcripts. For these processes to take place, vRNPs must pass through the cell nuclear pore complex (NPC) to the nucleus. The influenza A virus NS2 protein, also called the nuclear export protein (NES), has an important role in the nucleocytoplasmic transport of vRNPs. This protein interacts with the host cellular nucleoporins during the nuclear export of vRNPs. In this study, the human nucleoporin 214 (Nup214) was identified as an NS2-binding protein by using a yeast two-hybrid assay. The interaction between NS2 and human Nup214 was confirmed in both yeast and mammalian cells. It has been shown that the NS2 protein interacts with the amino terminal FG domain of the Nup214 protein. The influenza viral replication was suppressed in knockdown cells for the Nup214 protein. It was concluded that the FG domains of nucleoporins have an important role in the interaction of the influenza NS2 protein with host NPC for vRNA export.
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Affiliation(s)
- Burçak Şenbaş Akyazi
- Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Marmara University, İstanbul Turkey
| | - Ayşegül Pirinçal
- Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Marmara University, İstanbul Turkey
| | - Atsushi Kawaguchi
- Department of Infection Biology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba Japan
| | - Kyosuke Nagata
- Department of Infection Biology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba Japan
| | - Kadir Turan
- Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Marmara University, İstanbul Turkey
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83
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Moore S, Rabichow BE, Sattler R. The Hitchhiker's Guide to Nucleocytoplasmic Trafficking in Neurodegeneration. Neurochem Res 2020; 45:1306-1327. [PMID: 32086712 DOI: 10.1007/s11064-020-02989-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 12/12/2022]
Abstract
The widespread nature of nucleocytoplasmic trafficking defects and protein accumulation suggests distinct yet overlapping mechanisms in a variety of neurodegenerative diseases. Detailed understanding of the cellular pathways involved in nucleocytoplasmic transport and its dysregulation are essential for elucidating neurodegenerative pathogenesis and pinpointing potential areas for therapeutic intervention. The transport of cargos from the nucleus to the cytoplasm is generally regulated by the structure and function of the nuclear pore as well as the karyopherin α/β, importin, exportin, and mRNA export mechanisms. The disruption of these crucial transport mechanisms has been extensively described in the context of neurodegenerative diseases. One common theme in neurodegeneration is the cytoplasmic aggregation of proteins, including nuclear RNA binding proteins, repeat expansion associated gene products, and tau. These cytoplasmic aggregations are partly a consequence of failed nucleocytoplasmic transport machinery, but can also further disrupt transport, creating cyclical feed-forward mechanisms that exacerbate neurodegeneration. Here we describe the canonical mechanisms that regulate nucleocytoplasmic trafficking as well as how these mechanisms falter in neurodegenerative diseases.
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Affiliation(s)
- Stephen Moore
- Department of Neurobiology, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ, 85013, USA.,School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Benjamin E Rabichow
- Department of Neurobiology, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ, 85013, USA
| | - Rita Sattler
- Department of Neurobiology, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ, 85013, USA.
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84
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Okazaki R, Yamazoe K, Inoue YH. Nuclear Export of Cyclin B Mediated by the Nup62 Complex Is Required for Meiotic Initiation in Drosophila Males. Cells 2020; 9:E270. [PMID: 31979075 PMCID: PMC7072204 DOI: 10.3390/cells9020270] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/17/2020] [Accepted: 01/20/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND The central channel of the nuclear pore complex plays an important role in the selective transport of proteins between the nucleus and cytoplasm. Previous studies have demonstrated that the depletion of the Nup62 complex, constructing the nuclear pore channel in premeiotic Drosophila cells, resulted in the absence of meiotic cells. We attempted to understand the mechanism underlying the cell cycle arrest before meiosis. METHODS We induced dsRNAs against the nucleoporin mRNAs using the Gal4/UAS system in Drosophila. RESULTS The cell cycle of the Nup62-depleted cells was arrested before meiosis without CDK1 activation. The ectopic over-expression of CycB, but not constitutively active CDK1, resulted in partial rescue from the arrest. CycB continued to exist in the nuclei of Nup62-depleted cells and cells depleted of exportin encoded by emb. Protein complexes containing CycB, Emb, and Nup62 were observed in premeiotic spermatocytes. CycB, which had temporally entered the nucleus, was associated with Emb, and the complex was transported back to the cytoplasm through the central channel, interacting with the Nup62 complex. Conclusion: We proposed that CycB is exported with Emb through the channel interacting with the Nup62 complex before the onset of meiosis. The nuclear export ensures the modification and formation of sufficient CycB-CDK1 in the cytoplasm.
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Affiliation(s)
| | | | - Yoshihiro H. Inoue
- Department of Insect Biomedical Research, Center for Advanced Insect Research Promotion, Kyoto Institute of Technology, Kyoto, Japan; (R.O.); (K.Y.)
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85
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Mehta SJK, Kumar V, Mishra RK. Drosophila ELYS regulates Dorsal dynamics during development. J Biol Chem 2020; 295:2421-2437. [PMID: 31941789 DOI: 10.1074/jbc.ra119.009451] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 01/13/2020] [Indexed: 11/06/2022] Open
Abstract
Embryonic large molecule derived from yolk sac (ELYS) is a constituent protein of nuclear pores. It initiates assembly of nuclear pore complexes into functional nuclear pores toward the end of mitosis. Using cellular, molecular, and genetic tools, including fluorescence and Electron microscopy, quantitative PCR, and RNAi-mediated depletion, we report here that the ELYS ortholog (dElys) plays critical roles during Drosophila development. dElys localized to the nuclear rim in interphase cells, but during mitosis it was absent from kinetochores and enveloped chromatin. We observed that RNAi-mediated dElys depletion leads to aberrant development and, at the cellular level, to defects in the nuclear pore and nuclear lamina assembly. Further genetic analyses indicated that dElys depletion re-activates the Dorsal (NF-κB) pathway during late larval stages. Re-activated Dorsal caused untimely expression of the Dorsal target genes in the post-embryonic stages. We also demonstrate that activated Dorsal triggers apoptosis during later developmental stages by up-regulating the pro-apoptotic genes reaper and hid The apoptosis induced by Reaper and Hid was probably the underlying cause for developmental abnormalities observed upon dElys depletion. Moreover, we noted that dElys has conserved structural features, but contains a noncanonical AT-hook-like motif through which it strongly binds to DNA. Together, our results uncover a novel epistatic interaction that regulates Dorsal dynamics by dElys during development.
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Affiliation(s)
- Saurabh Jayesh Kumar Mehta
- Nups and SUMO Biology Group, Department of Biological Sciences, Academic Building 3, Indian Institute of Science Education and Research-Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, Madhya Pradesh-462066, India
| | - Vimlesh Kumar
- Laboratory of Neurogenetics, Department of Biological Sciences, Academic Building 3, Indian Institute of Science Education and Research-Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, Madhya Pradesh-462066, India
| | - Ram Kumar Mishra
- Nups and SUMO Biology Group, Department of Biological Sciences, Academic Building 3, Indian Institute of Science Education and Research-Bhopal, Bhopal By-pass Road, Bhauri, Bhopal, Madhya Pradesh-462066, India.
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86
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Blus BJ, Koh J, Krolak A, Seo HS, Coutavas E, Blobel G. Allosteric modulation of nucleoporin assemblies by intrinsically disordered regions. SCIENCE ADVANCES 2019; 5:eaax1836. [PMID: 31807700 PMCID: PMC6881172 DOI: 10.1126/sciadv.aax1836] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 09/25/2019] [Indexed: 05/12/2023]
Abstract
Intrinsically disordered regions (IDRs) of proteins are implicated in key macromolecular interactions. However, the molecular forces underlying IDR function within multicomponent assemblies remain elusive. By combining thermodynamic and structural data, we have discovered an allostery-based mechanism regulating the soluble core region of the nuclear pore complex (NPC) composed of nucleoporins Nup53, Nic96, and Nup157. We have identified distinct IDRs in Nup53 that are functionally coupled when binding to partner nucleoporins and karyopherins (Kaps) involved in NPC assembly and nucleocytoplasmic transport. We show that the Nup53·Kap121 complex forms an ensemble of structures that destabilize Nup53 hub interactions. Our study provides a molecular framework for understanding how disordered and folded domains communicate within macromolecular complexes.
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Affiliation(s)
- Bartlomiej Jan Blus
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
- Corresponding author.
| | - Junseock Koh
- School of Biological Sciences, Seoul National University, Seoul, 08826, South Korea
| | - Aleksandra Krolak
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Hyuk-Soo Seo
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Elias Coutavas
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Günter Blobel
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
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87
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Hampoelz B, Schwarz A, Ronchi P, Bragulat-Teixidor H, Tischer C, Gaspar I, Ephrussi A, Schwab Y, Beck M. Nuclear Pores Assemble from Nucleoporin Condensates During Oogenesis. Cell 2019; 179:671-686.e17. [PMID: 31626769 PMCID: PMC6838685 DOI: 10.1016/j.cell.2019.09.022] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 08/09/2019] [Accepted: 09/20/2019] [Indexed: 02/02/2023]
Abstract
The molecular events that direct nuclear pore complex (NPC) assembly toward nuclear envelopes have been conceptualized in two pathways that occur during mitosis or interphase, respectively. In gametes and embryonic cells, NPCs also occur within stacked cytoplasmic membrane sheets, termed annulate lamellae (AL), which serve as NPC storage for early development. The mechanism of NPC biogenesis at cytoplasmic membranes remains unknown. Here, we show that during Drosophila oogenesis, Nucleoporins condense into different precursor granules that interact and progress into NPCs. Nup358 is a key player that condenses into NPC assembly platforms while its mRNA localizes to their surface in a translation-dependent manner. In concert, Microtubule-dependent transport, the small GTPase Ran and nuclear transport receptors regulate NPC biogenesis in oocytes. We delineate a non-canonical NPC assembly mechanism that relies on Nucleoporin condensates and occurs away from the nucleus under conditions of cell cycle arrest.
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Affiliation(s)
- Bernhard Hampoelz
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany; Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
| | - Andre Schwarz
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany; Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Paolo Ronchi
- European Molecular Biology Laboratory, Electron Microscopy Core Facility, Heidelberg, Germany
| | | | - Christian Tischer
- Center for Bioimage Analysis, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Imre Gaspar
- European Molecular Biology Laboratory, Developmental Biology Unit, Heidelberg, Germany
| | - Anne Ephrussi
- European Molecular Biology Laboratory, Developmental Biology Unit, Heidelberg, Germany
| | - Yannick Schwab
- European Molecular Biology Laboratory, Electron Microscopy Core Facility, Heidelberg, Germany; European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany
| | - Martin Beck
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany; Max Planck Institute of Biophysics, Frankfurt am Main, Germany; European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany.
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88
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Abstract
During my postdoc interview in June of 1998, I asked Günter why he was moving more towards the nucleus in his latest studies. He said, "Well Joe, that's where everything starts." By the end of the interview, I accepted the postdoc. He had a way of making everything sound so cool. Günter's progression was natural, since the endoplasmic reticulum and the nucleus are the only organelles that share the same membrane. The nuclear envelope extends into a double membrane system with nuclear pore complexes embedded in the pore membrane openings. Even while writing this review, I remember Günter stressing; it is the nuclear pore complex. Just saying nuclear pore doesn't encompass the full magnitude of its significance. The nuclear pore complex is one of the largest collection of proteins that fit together for an overall function: transport. This review will cover the Blobel lab contributions in the quest for the blueprint of the nuclear pore complex from isolation of the nuclear envelope and nuclear lamin to the ring structures.
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89
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Proteomic and genomic signatures of repeat instability in cancer and adjacent normal tissues. Proc Natl Acad Sci U S A 2019; 116:16987-16996. [PMID: 31387980 DOI: 10.1073/pnas.1908790116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Repetitive sequences are hotspots of evolution at multiple levels. However, due to difficulties involved in their assembly and analysis, the role of repeats in tumor evolution is poorly understood. We developed a rigorous motif-based methodology to quantify variations in the repeat content, beyond microsatellites, in proteomes and genomes directly from proteomic and genomic raw data. This method was applied to a wide range of tumors and normal tissues. We identify high similarity between repeat instability patterns in tumors and their patient-matched adjacent normal tissues. Nonetheless, tumor-specific signatures both in protein expression and in the genome strongly correlate with cancer progression and robustly predict the tumorigenic state. In a patient, the hierarchy of genomic repeat instability signatures accurately reconstructs tumor evolution, with primary tumors differentiated from metastases. We observe an inverse relationship between repeat instability and point mutation load within and across patients independent of other somatic aberrations. Thus, repeat instability is a distinct, transient, and compensatory adaptive mechanism in tumor evolution and a potential signal for early detection.
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90
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Fichtman B, Harel T, Biran N, Zagairy F, Applegate CD, Salzberg Y, Gilboa T, Salah S, Shaag A, Simanovsky N, Ayoubieh H, Sobreira N, Punzi G, Pierri CL, Hamosh A, Elpeleg O, Harel A, Edvardson S. Pathogenic Variants in NUP214 Cause "Plugged" Nuclear Pore Channels and Acute Febrile Encephalopathy. Am J Hum Genet 2019; 105:48-64. [PMID: 31178128 DOI: 10.1016/j.ajhg.2019.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 05/06/2019] [Indexed: 12/15/2022] Open
Abstract
We report biallelic missense and frameshift pathogenic variants in the gene encoding human nucleoporin NUP214 causing acute febrile encephalopathy. Clinical symptoms include neurodevelopmental regression, seizures, myoclonic jerks, progressive microcephaly, and cerebellar atrophy. NUP214 and NUP88 protein levels were reduced in primary skin fibroblasts derived from affected individuals, while the total number and density of nuclear pore complexes remained normal. Nuclear transport assays exhibited defects in the classical protein import and mRNA export pathways in affected cells. Direct surface imaging of fibroblast nuclei by scanning electron microscopy revealed a large increase in the presence of central particles (known as "plugs") in the nuclear pore channels of affected cells. This observation suggests that large transport cargoes may be delayed in passage through the nuclear pore channel, affecting its selective barrier function. Exposure of fibroblasts from affected individuals to heat shock resulted in a marked delay in their stress response, followed by a surge in apoptotic cell death. This suggests a mechanistic link between decreased cell survival in cell culture and severe fever-induced brain damage in affected individuals. Our study provides evidence by direct imaging at the single nuclear pore level of functional changes linked to a human disease.
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Affiliation(s)
- Boris Fichtman
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel
| | - Tamar Harel
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Nitzan Biran
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel
| | - Fadia Zagairy
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel
| | - Carolyn D Applegate
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Yuval Salzberg
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel
| | - Tal Gilboa
- Pediatric Neurology Unit, Hadassah-Hebrew University Medical Center, Jerusalem 91240, Israel
| | - Somaya Salah
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Avraham Shaag
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel; Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Natalia Simanovsky
- Department of Medical Imaging, Hadassah Medical Center, Jerusalem 91240, Israel
| | - Houriya Ayoubieh
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Baylor-Hopkins Center for Mendelian Genomics, Jerusalem 91240, Israel, Jerusalem 91240, Israel
| | - Nara Sobreira
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Baylor-Hopkins Center for Mendelian Genomics, Jerusalem 91240, Israel, Jerusalem 91240, Israel
| | - Giuseppe Punzi
- Laboratory of Biochemistry, Molecular and Computational Biology; Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Ciro Leonardo Pierri
- Laboratory of Biochemistry, Molecular and Computational Biology; Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Ada Hamosh
- McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Baylor-Hopkins Center for Mendelian Genomics, Jerusalem 91240, Israel, Jerusalem 91240, Israel
| | - Orly Elpeleg
- Department of Genetic and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel; Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Amnon Harel
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel.
| | - Simon Edvardson
- Pediatric Neurology Unit, Hadassah-Hebrew University Medical Center, Jerusalem 91240, Israel; Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
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91
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Rodriguez CM, Todd PK. New pathologic mechanisms in nucleotide repeat expansion disorders. Neurobiol Dis 2019; 130:104515. [PMID: 31229686 DOI: 10.1016/j.nbd.2019.104515] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/07/2019] [Accepted: 06/19/2019] [Indexed: 12/14/2022] Open
Abstract
Tandem microsatellite repeats are common throughout the human genome and intrinsically unstable, exhibiting expansions and contractions both somatically and across generations. Instability in a small subset of these repeats are currently linked to human disease, although recent findings suggest more disease-causing repeats await discovery. These nucleotide repeat expansion disorders (NREDs) primarily affect the nervous system and commonly lead to neurodegeneration through toxic protein gain-of-function, protein loss-of-function, and toxic RNA gain-of-function mechanisms. However, the lines between these categories have blurred with recent findings of unconventional Repeat Associated Non-AUG (RAN) translation from putatively non-coding regions of the genome. Here we review two emerging topics in NREDs: 1) The mechanisms by which RAN translation occurs and its role in disease pathogenesis and 2) How nucleotide repeats as RNA and translated proteins influence liquid-liquid phase separation, membraneless organelle dynamics, and nucleocytoplasmic transport. We examine these topics with a particular eye on two repeats: the CGG repeat expansion responsible for Fragile X syndrome and Fragile X-associated Tremor Ataxia Syndrome (FXTAS) and the intronic GGGGCC repeat expansion in C9orf72, the most common inherited cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Our thesis is that these emerging disease mechanisms can inform a broader understanding of the native roles of microsatellites in cellular function and that aberrations in these native processes provide clues to novel therapeutic strategies for these currently untreatable disorders.
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Affiliation(s)
- C M Rodriguez
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Department of Genetics, Stanford University, Stanford, CA, USA
| | - P K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
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92
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Nucleoporin Nup155 is part of the p53 network in liver cancer. Nat Commun 2019; 10:2147. [PMID: 31089132 PMCID: PMC6517424 DOI: 10.1038/s41467-019-10133-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 04/16/2019] [Indexed: 02/08/2023] Open
Abstract
Cancer-relevant signalling pathways rely on bidirectional nucleocytoplasmic transport events through the nuclear pore complex (NPC). However, mechanisms by which individual NPC components (Nups) participate in the regulation of these pathways remain poorly understood. We discover by integrating large scale proteomics, polysome fractionation and a focused RNAi approach that Nup155 controls mRNA translation of p21 (CDKN1A), a key mediator of the p53 response. The underlying mechanism involves transcriptional regulation of the putative tRNA and rRNA methyltransferase FTSJ1 by Nup155. Furthermore, we observe that Nup155 and FTSJ1 are p53 repression targets and accordingly find a correlation between the p53 status, Nup155 and FTSJ1 expression in murine and human hepatocellular carcinoma. Our data suggest an unanticipated regulatory network linking translational control by and repression of a structural NPC component modulating the p53 pathway through its effectors. The nuclear pore complex (NPC) is known to regulate p53 signaling and this has mainly been linked to peripheral NPC subunits. Here the authors show that Nup155 from the NPC inner ring regulates the p53 pathway by controlling p21 translation while also being a target of p53-mediated repression.
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93
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Abstract
Nuclear pore complexes (NPCs) mediate nucleocytoplasmic exchange. They are exceptionally large protein complexes that fuse the inner and outer nuclear membranes to form channels across the nuclear envelope. About 30 different protein components, termed nucleoporins, assemble in multiple copies into an intricate cylindrical architecture. Here, we review our current knowledge of the structure of nucleoporins and how those come together in situ. We delineate architectural principles on several hierarchical organization levels, including isoforms, posttranslational modifications, nucleoporins, and higher-order oligomerization of nucleoporin subcomplexes. We discuss how cells exploit this modularity to faithfully assemble NPCs.
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Affiliation(s)
- Bernhard Hampoelz
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; , ,
| | - Amparo Andres-Pons
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; , , .,Current affiliation: Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland;
| | - Panagiotis Kastritis
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; , , .,Current affiliation: ZIK HALOmem, Martin Luther University of Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany; , , .,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
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94
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Abstract
The nuclear pore complex (NPC) serves as the sole bidirectional gateway of macromolecules in and out of the nucleus. Owing to its size and complexity (∼1,000 protein subunits, ∼110 MDa in humans), the NPC has remained one of the foremost challenges for structure determination. Structural studies have now provided atomic-resolution crystal structures of most nucleoporins. The acquisition of these structures, combined with biochemical reconstitution experiments, cross-linking mass spectrometry, and cryo-electron tomography, has facilitated the determination of the near-atomic overall architecture of the symmetric core of the human, fungal, and algal NPCs. Here, we discuss the insights gained from these new advances and outstanding issues regarding NPC structure and function. The powerful combination of bottom-up and top-down approaches toward determining the structure of the NPC offers a paradigm for uncovering the architectures of other complex biological machines to near-atomic resolution.
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Affiliation(s)
- Daniel H Lin
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA;
| | - André Hoelz
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA;
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95
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Moura M, Conde C. Phosphatases in Mitosis: Roles and Regulation. Biomolecules 2019; 9:E55. [PMID: 30736436 PMCID: PMC6406801 DOI: 10.3390/biom9020055] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 02/07/2023] Open
Abstract
Mitosis requires extensive rearrangement of cellular architecture and of subcellular structures so that replicated chromosomes can bind correctly to spindle microtubules and segregate towards opposite poles. This process originates two new daughter nuclei with equal genetic content and relies on highly-dynamic and tightly regulated phosphorylation of numerous cell cycle proteins. A burst in protein phosphorylation orchestrated by several conserved kinases occurs as cells go into and progress through mitosis. The opposing dephosphorylation events are catalyzed by a small set of protein phosphatases, whose importance for the accuracy of mitosis is becoming increasingly appreciated. This review will focus on the established and emerging roles of mitotic phosphatases, describe their structural and biochemical properties, and discuss recent advances in understanding the regulation of phosphatase activity and function.
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Affiliation(s)
- Margarida Moura
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
- i3S-Instituto de Investigação e Inovação em Saúde da Universidade do Porto, 4200-135, Porto, Portugal.
- Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, 4050-313 Porto, Portugal.
| | - Carlos Conde
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
- i3S-Instituto de Investigação e Inovação em Saúde da Universidade do Porto, 4200-135, Porto, Portugal.
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96
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Meng W, Wang XJ, Wang HCR. Targeting nuclear proteins for control of viral replication. Crit Rev Microbiol 2019; 45:495-513. [DOI: 10.1080/1040841x.2018.1553848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Wen Meng
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xiao-Jia Wang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Hwa-Chain Robert Wang
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, USA
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97
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Guan Y, Gao X, Tang Q, Huang L, Gao S, Yu S, Huang J, Li J, Zhou D, Zhang Y, Shi D, Liang D, Liu Y, Li L, Cui Y, Xu L, Chen YH. Nucleoporin 107 facilitates the nuclear export of Scn5a mRNA to regulate cardiac bioelectricity. J Cell Mol Med 2018; 23:1448-1457. [PMID: 30506890 PMCID: PMC6349201 DOI: 10.1111/jcmm.14051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/13/2018] [Accepted: 11/05/2018] [Indexed: 01/02/2023] Open
Abstract
Nucleoporins (Nups) are known to be functional in nucleo‐cytoplasmic transport, but the roles of nucleoporins in nonproliferating cells, such as cardiac myocytes, are still poorly understood. In this study, we report that Nup107 regulates cardiac bioelectricity by controlling the nucleo‐cytoplasmic trafficking of Scn5a mRNA. Overexpression of Nup107 induced the protein expression of Scn5a rather than that of other ion channels, with no effects of their mRNA levels. The analysis for the protein production demonstrated Nup107‐facilitated transport of Scn5a mRNA. Using RIP‐PCR and luciferase assay, we found that the 5′‐UTR of Scn5a mRNA was not involved in the interaction, whereas the spatial interaction between Nup107 protein and Scn5a mRNA was formed when Scn5a mRNA passing through the nuclear pore. Functionally, Nup107 overexpression in neonatal rat ventricle myocytes significantly increased the currents of Scn5a‐encoded INa channel. Moreover, the close correlation between Nup107 and Nav1.5 protein expression was observed in cardiomycytes and heart tissues subjected to hypoxia and ischaemic insults, suggesting a fast regulation of Nup107 on Nav1.5 channel in cardiac myocytes in a posttranscriptional manner. These findings may provide insights into the emergent control of cardiac electrophysiology through Nup‐mediated modulation of ion channels.
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Affiliation(s)
- Yi Guan
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Xueting Gao
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Qiuyu Tang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Lin Huang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Siyun Gao
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Shuai Yu
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China
| | - Jiale Huang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jun Li
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Daizhan Zhou
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yangyang Zhang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Dan Shi
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Dandan Liang
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yi Liu
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Li Li
- Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Yingyu Cui
- Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
| | - Liang Xu
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yi-Han Chen
- Heart Health Center, East Hospital, Tongji University School of Medicine, Shanghai, China.,Institute of Medical Genetics, Tongji University, Shanghai, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Pathology and Pathophysiology, Tongji University School of Medicine, Shanghai, China
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98
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Dicks MDJ, Betancor G, Jimenez-Guardeño JM, Pessel-Vivares L, Apolonia L, Goujon C, Malim MH. Multiple components of the nuclear pore complex interact with the amino-terminus of MX2 to facilitate HIV-1 restriction. PLoS Pathog 2018; 14:e1007408. [PMID: 30496303 PMCID: PMC6264145 DOI: 10.1371/journal.ppat.1007408] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 10/15/2018] [Indexed: 12/13/2022] Open
Abstract
Human myxovirus resistance 2 (MX2/MXB) is an interferon-induced post-entry inhibitor of human immunodeficiency virus type-1 (HIV-1) infection. While the precise mechanism of viral inhibition remains unclear, MX2 is localized to the nuclear envelope, and blocks the nuclear import of viral cDNAs. The amino-terminus of MX2 (N-MX2) is essential for anti-viral function, and mutation of a triple arginine motif at residues 11 to 13 abrogates anti-HIV-1 activity. In this study, we sought to investigate the role of N-MX2 in anti-viral activity by identifying functionally relevant host-encoded interaction partners through yeast-two-hybrid screening. Remarkably, five out of seven primary candidate interactors were nucleoporins or nucleoporin-like proteins, though none of these candidates were identified when screening with a mutant RRR11-13A N-MX2 fragment. Interactions were confirmed by co-immunoprecipitation, and RNA silencing experiments in cell lines and primary CD4+ T cells demonstrated that multiple components of the nuclear pore complex and nuclear import machinery can impact MX2 anti-viral activity. In particular, the phenylalanine-glycine (FG) repeat containing cytoplasmic filament nucleoporin NUP214, and transport receptor transportin-1 (TNPO1) were consistently required for full MX2, and interferon-mediated, anti-viral function. Both proteins were shown to interact with the triple arginine motif, and confocal fluorescence microscopy revealed that their simultaneous depletion resulted in diminished MX2 accumulation at the nuclear envelope. We therefore propose a model whereby multiple components of the nuclear import machinery and nuclear pore complex help position MX2 at the nuclear envelope to promote MX2-mediated restriction of HIV-1. The movement of large molecules into the cell nucleus is regulated at specific sites within the nuclear envelope termed nuclear pores. To infect cells productively, human immunodeficiency virus type-1 (HIV-1) must traverse the nuclear envelope to enable integration of the viral DNA into the genomic DNA of host cells. We, and others, have previously identified a cell-encoded protein, human myxovirus resistance 2 (MX2), which is expressed upon initiation of an innate immune response and prevents accumulation of HIV-1 DNA within the nucleus, thus imposing a block to infection. Here, we reveal that components of the nuclear pore complex, and nuclear import machinery, are required for MX2-dependent inhibition of HIV-1 infection. We show that MX2, which is localized at the cytoplasmic face of the nuclear envelope, interacts with multiple protein components of the nuclear pore complex, as well as transport receptor transportin-1, via a functionally required triple arginine motif at its amino-terminus. We speculate that these interactions facilitate MX2-mediated inhibition of HIV-1 nuclear import by situating the protein at the nuclear envelope.
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Affiliation(s)
- Matthew D. J. Dicks
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Gilberto Betancor
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Jose M. Jimenez-Guardeño
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Lucie Pessel-Vivares
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Luis Apolonia
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Caroline Goujon
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
| | - Michael H. Malim
- Department of Infectious Diseases, School of Immunology & Microbial Sciences, King’s College London, London, United Kingdom
- * E-mail:
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99
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Mertens J, Reid D, Lau S, Kim Y, Gage FH. Aging in a Dish: iPSC-Derived and Directly Induced Neurons for Studying Brain Aging and Age-Related Neurodegenerative Diseases. Annu Rev Genet 2018; 52:271-293. [PMID: 30208291 DOI: 10.1146/annurev-genet-120417-031534] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Age-associated neurological diseases represent a profound challenge in biomedical research as we are still struggling to understand the interface between the aging process and the manifestation of disease. Various pathologies in the elderly do not directly result from genetic mutations, toxins, or infectious agents but are primarily driven by the many manifestations of biological aging. Therefore, the generation of appropriate model systems to study human aging in the nervous system demands new concepts that lie beyond transgenic and drug-induced models. Although access to viable human brain specimens is limited and induced pluripotent stem cell models face limitations due to reprogramming-associated cellular rejuvenation, the direct conversion of somatic cells into induced neurons allows for the generation of human neurons that capture many aspects of aging. Here, we review advances in exploring age-associated neurodegenerative diseases using human cell reprogramming models, and we discuss general concepts, promises, and limitations of the field.
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Affiliation(s)
- Jerome Mertens
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA; .,Department of Genomics, Stem Cell Biology and Regenerative Medicine, Institute of Molecular Biology, and Center for Molecular Biosciences Innsbruck, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Dylan Reid
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA;
| | - Shong Lau
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA;
| | - Yongsung Kim
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA;
| | - Fred H Gage
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA;
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100
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Flather D, Nguyen JHC, Semler BL, Gershon PD. Exploitation of nuclear functions by human rhinovirus, a cytoplasmic RNA virus. PLoS Pathog 2018; 14:e1007277. [PMID: 30142213 PMCID: PMC6126879 DOI: 10.1371/journal.ppat.1007277] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 09/06/2018] [Accepted: 08/11/2018] [Indexed: 12/17/2022] Open
Abstract
Protein production, genomic RNA replication, and virion assembly during infection by picornaviruses like human rhinovirus and poliovirus take place in the cytoplasm of infected human cells, making them the quintessential cytoplasmic pathogens. However, a growing body of evidence suggests that picornavirus replication is promoted by a number of host proteins localized normally within the host cell nucleus. To systematically identify such nuclear proteins, we focused on those that appear to re-equilibrate from the nucleus to the cytoplasm during infection of HeLa cells with human rhinovirus via quantitative protein mass spectrometry. Our analysis revealed a highly selective re-equilibration of proteins with known mRNA splicing and transport-related functions over nuclear proteins of all other functional classes. The multifunctional splicing factor proline and glutamine rich (SFPQ) was identified as one such protein. We found that SFPQ is targeted for proteolysis within the nucleus by viral proteinase 3CD/3C, and a fragment of SFPQ was shown to migrate to the cytoplasm at mid-to-late times of infection. Cells knocked down for SFPQ expression showed significantly reduced rhinovirus titers, viral protein production, and viral RNA accumulation, consistent with SFPQ being a pro-viral factor. The SFPQ fragment that moved into the cytoplasm was able to bind rhinovirus RNA either directly or indirectly. We propose that the truncated form of SFPQ promotes viral RNA stability or replication, or virion morphogenesis. More broadly, our findings reveal dramatic changes in protein compartmentalization during human rhinovirus infection, allowing the virus to systematically hijack the functions of proteins not normally found at its cytoplasmic site of replication. We explored the dynamics of host cell protein relocalization from the nucleus to the cytoplasm during an infection by human rhinovirus using quantitative mass spectrometry, confocal imaging, and Western blot analysis. We discovered a highly selective re-equilibration of proteins with known mRNA splicing and transport-related functions, including splicing factor proline and glutamine rich (SFPQ). Using RNAi experiments and viral replication assays, we demonstrated that SFPQ is a pro-viral factor required for rhinovirus growth. Our studies provide new insights into how this cytoplasmic RNA virus is able to alter and hijack the functions of host proteins that normally reside in the nucleus.
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Affiliation(s)
- Dylan Flather
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, California, United States of America
- Center for Virus Research, University of California, Irvine, California, United States of America
| | - Joseph H. C. Nguyen
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, California, United States of America
- Center for Virus Research, University of California, Irvine, California, United States of America
| | - Bert L. Semler
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, California, United States of America
- Center for Virus Research, University of California, Irvine, California, United States of America
- * E-mail: (BLS); (PDG)
| | - Paul D. Gershon
- Center for Virus Research, University of California, Irvine, California, United States of America
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California, United States of America
- * E-mail: (BLS); (PDG)
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