51
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Benarroch EE. Nucleocytoplasmic transport: Mechanisms and involvement in neurodegenerative disease. Neurology 2019; 92:757-764. [PMID: 30894450 DOI: 10.1212/wnl.0000000000007305] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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52
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Guo L, Fare CM, Shorter J. Therapeutic Dissolution of Aberrant Phases by Nuclear-Import Receptors. Trends Cell Biol 2019; 29:308-322. [PMID: 30660504 DOI: 10.1016/j.tcb.2018.12.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/11/2018] [Accepted: 12/14/2018] [Indexed: 12/14/2022]
Abstract
Nuclear-import receptors (NIRs) bind nuclear-localization signals (NLSs) of protein cargo in the cytoplasm and transport them into the nucleus. Here, we review advances establishing that NIRs also function in the cytoplasm to prevent and reverse functional and aberrant phase transitions of their cargo, including neurodegenerative disease-linked RNA-binding proteins (RBPs) with prion-like domains, such as TDP-43, FUS, hnRNPA1, and hnRNPA2. NIRs selectively extract cargo from condensed liquid phases thereby regulating functional phase separation. Consequently, NIRs sculpt cytoplasmic membraneless organelles and regulate cellular organization beyond their canonical role in nuclear import. Elevating NIR expression dissolves cytoplasmic RBP aggregates, restores functional RBPs to the nucleus, and rescues disease-linked RBP toxicity. Thus, NIRs could be leveraged therapeutically to restore RBP homeostasis and mitigate neurodegeneration.
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Affiliation(s)
- Lin Guo
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Joint first authors
| | - Charlotte M Fare
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Joint first authors
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Bodak M, Yu J, Ciaudo C. Regulation of LINE-1 Elements by miR-128 Is Not Conserved in Mouse Embryonic Stem Cells. Front Genet 2018; 9:683. [PMID: 30619491 PMCID: PMC6306448 DOI: 10.3389/fgene.2018.00683] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 12/07/2018] [Indexed: 12/22/2022] Open
Affiliation(s)
- Maxime Bodak
- Department of Biology, Swiss Federal Institute of Technology Zurich, IMHS, Zurich, Switzerland
| | - Jian Yu
- Department of Biology, Swiss Federal Institute of Technology Zurich, IMHS, Zurich, Switzerland
| | - Constance Ciaudo
- Department of Biology, Swiss Federal Institute of Technology Zurich, IMHS, Zurich, Switzerland
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54
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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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Duan Z, Xu H, Ji X, Zhao J, Xu H, Hu Y, Deng S, Hu S, Liu X. Importin α5 negatively regulates importin β1-mediated nuclear import of Newcastle disease virus matrix protein and viral replication and pathogenicity in chicken fibroblasts. Virulence 2018. [PMID: 29532715 PMCID: PMC5955436 DOI: 10.1080/21505594.2018.1449507] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The matrix (M) protein of Newcastle disease virus (NDV) is demonstrated to localize in the nucleus via intrinsic nuclear localization signal (NLS), but cellular proteins involved in the nuclear import of NDV M protein and the role of M's nuclear localization in the replication and pathogenicity of NDV remain unclear. In this study, importin β1 was screened to interact with NDV M protein by yeast two-hybrid screening. This interaction was subsequently confirmed by co-immunoprecipitation and pull-down assays. In vitro binding studies indicated that the NLS region of M protein and the amino acids 336–433 of importin β1 that belonged to the RanGTP binding region were important for binding. Importantly, a recombinant virus with M/NLS mutation resulted in a pathotype change of NDV and attenuated viral replication and pathogenicity in chicken fibroblasts and SPF chickens. In agreement with the binding data, nuclear import of NDV M protein in digitonin-permeabilized HeLa cells required both importin β1 and RanGTP. Interestingly, importin α5 was verified to interact with M protein through binding importin β1. However, importin β1 or importin α5 depletion by siRNA resulted in different results, which showed the obviously cytoplasmic or nuclear accumulation of M protein and the remarkably decreased or increased replication ability and pathogenicity of NDV in chicken fibroblasts, respectively. Our findings therefore demonstrate for the first time the nuclear import mechanism of NDV M protein and the negative regulation role of importin α5 in importin β1-mediated nuclear import of M protein and the replication and pathogenicity of a paramyxovirus.
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Affiliation(s)
- Zhiqiang Duan
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Haixu Xu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
| | - Xinqin Ji
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Jiafu Zhao
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Houqiang Xu
- a Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education , Guizhou University , Guiyang , China.,b College of Animal Science , Guizhou University , Guiyang , China
| | - Yan Hu
- b College of Animal Science , Guizhou University , Guiyang , China
| | - Shanshan Deng
- b College of Animal Science , Guizhou University , Guiyang , China
| | - Shunlin Hu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
| | - Xiufan Liu
- c Key Laboratory of Animal Infectious Diseases of Ministry of Agriculture , Yangzhou University , Yangzhou , China
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56
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Tanaka T, Kasai M, Kobayashi S. Mechanism responsible for inhibitory effect of indirubin 3′-oxime on anticancer agent-induced YB-1 nuclear translocation in HepG2 human hepatocellular carcinoma cells. Exp Cell Res 2018; 370:454-460. [DOI: 10.1016/j.yexcr.2018.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/03/2018] [Indexed: 12/23/2022]
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Purice MD, Taylor JP. Linking hnRNP Function to ALS and FTD Pathology. Front Neurosci 2018; 12:326. [PMID: 29867335 PMCID: PMC5962818 DOI: 10.3389/fnins.2018.00326] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/26/2018] [Indexed: 12/12/2022] Open
Abstract
Following years of rapid progress identifying the genetic underpinnings of amyotrophic lateral sclerosis (ALS) and related diseases such as frontotemporal dementia (FTD), remarkable consistencies have emerged pointing to perturbed biology of heterogeneous nuclear ribonucleoproteins (hnRNPs) as a central driver of pathobiology. To varying extents these RNA-binding proteins are deposited in pathological inclusions in affected tissues in ALS and FTD. Moreover, mutations in hnRNPs account for a significant number of familial cases of ALS and FTD. Here we review the normal function and potential pathogenic contribution of TDP-43, FUS, hnRNP A1, hnRNP A2B1, MATR3, and TIA1 to disease. We highlight recent evidence linking the low complexity sequence domains (LCDs) of these hnRNPs to the formation of membraneless organelles and discuss how alterations in the dynamics of these organelles could contribute to disease. In particular, we discuss the various roles of disease-associated hnRNPs in stress granule assembly and disassembly, and examine the emerging hypothesis that disease-causing mutations in these proteins lead to accumulation of persistent stress granules.
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Affiliation(s)
- Maria D Purice
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - J Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, United States.,Howard Hughes Medical Institute, Chevy Chase, MD, United States
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58
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St George-Hyslop P, Lin JQ, Miyashita A, Phillips EC, Qamar S, Randle SJ, Wang G. The physiological and pathological biophysics of phase separation and gelation of RNA binding proteins in amyotrophic lateral sclerosis and fronto-temporal lobar degeneration. Brain Res 2018; 1693:11-23. [PMID: 29723523 PMCID: PMC6018615 DOI: 10.1016/j.brainres.2018.04.036] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 12/12/2022]
Abstract
Some intrinsically disordered proteins undergo reversible phase separation/gelation. Reversible phase separation/gelation underpins function of membraneless organelles. fALS-FUS mutations increase propensity of FUS to form highly stable condensates. Changes in arginine methylation and FUS chaperones in FTLD-FUS have similar effects. Stable fibrillar condensates sequester cargo and impair RNP granule function.
Many RNA binding proteins, including FUS, contain moderately repetitive, low complexity, intrinsically disordered domains. These sequence motifs have recently been found to underpin reversible liquid: liquid phase separation and gelation of these proteins, permitting them to reversibly transition from a monodispersed state to liquid droplet- or hydrogel-like states. This function allows the proteins to serve as scaffolds for the formation of reversible membraneless intracellular organelles such as nucleoli, stress granules and neuronal transport granules. Using FUS as an example, this review examines the biophysics of this physiological process, and reports on how mutations and changes in post-translational state alter phase behaviour, and lead to neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration.
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Affiliation(s)
- Peter St George-Hyslop
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK; Tanz Centre for Research in Neurodegenerative Diseases, and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 3H2, Canada.
| | - Julie Qiaojin Lin
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Akinori Miyashita
- Tanz Centre for Research in Neurodegenerative Diseases, and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 3H2, Canada
| | - Emma C Phillips
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - Seema Qamar
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - Suzanne J Randle
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - GuoZhen Wang
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
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59
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Qamar S, Wang G, Randle SJ, Ruggeri FS, Varela JA, Lin JQ, Phillips EC, Miyashita A, Williams D, Ströhl F, Meadows W, Ferry R, Dardov VJ, Tartaglia GG, Farrer LA, Kaminski Schierle GS, Kaminski CF, Holt CE, Fraser PE, Schmitt-Ulms G, Klenerman D, Knowles T, Vendruscolo M, St George-Hyslop P. FUS Phase Separation Is Modulated by a Molecular Chaperone and Methylation of Arginine Cation-π Interactions. Cell 2018; 173:720-734.e15. [PMID: 29677515 PMCID: PMC5927716 DOI: 10.1016/j.cell.2018.03.056] [Citation(s) in RCA: 537] [Impact Index Per Article: 89.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Revised: 12/11/2017] [Accepted: 03/21/2018] [Indexed: 11/25/2022]
Abstract
Reversible phase separation underpins the role of FUS in ribonucleoprotein granules and other membrane-free organelles and is, in part, driven by the intrinsically disordered low-complexity (LC) domain of FUS. Here, we report that cooperative cation-π interactions between tyrosines in the LC domain and arginines in structured C-terminal domains also contribute to phase separation. These interactions are modulated by post-translational arginine methylation, wherein arginine hypomethylation strongly promotes phase separation and gelation. Indeed, significant hypomethylation, which occurs in FUS-associated frontotemporal lobar degeneration (FTLD), induces FUS condensation into stable intermolecular β-sheet-rich hydrogels that disrupt RNP granule function and impair new protein synthesis in neuron terminals. We show that transportin acts as a physiological molecular chaperone of FUS in neuron terminals, reducing phase separation and gelation of methylated and hypomethylated FUS and rescuing protein synthesis. These results demonstrate how FUS condensation is physiologically regulated and how perturbations in these mechanisms can lead to disease.
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Affiliation(s)
- Seema Qamar
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - GuoZhen Wang
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - Suzanne J Randle
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | | | - Juan A Varela
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Julie Qiaojin Lin
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Emma C Phillips
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - Akinori Miyashita
- Tanz Centre for Research in Neurodegenerative Diseases and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 3H2, Canada
| | - Declan Williams
- Tanz Centre for Research in Neurodegenerative Diseases and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 3H2, Canada
| | - Florian Ströhl
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, UK
| | - William Meadows
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - Rodylyn Ferry
- Tanz Centre for Research in Neurodegenerative Diseases and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 3H2, Canada
| | - Victoria J Dardov
- Department of Biomedical Sciences, Cedars Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Gian G Tartaglia
- Centre for Genomic Regulation, the Barcelona Institute for Science and Technology, 08003 Barcelona, Spain; Universitat Pompeu Fabra, 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - Lindsay A Farrer
- Departments of Medicine, Neurology, and Ophthalmology and Departments of Epidemiology and Biostatistics, Boston University, Boston, MA 02118, USA
| | | | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, UK
| | - Christine E Holt
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Paul E Fraser
- Tanz Centre for Research in Neurodegenerative Diseases and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 3H2, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 3H2, Canada
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Tuomas Knowles
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK; Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
| | | | - Peter St George-Hyslop
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK; Tanz Centre for Research in Neurodegenerative Diseases and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 3H2, Canada.
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Matsumoto K, Kose S, Kuwahara I, Yoshimura M, Imamoto N, Yoshida M. Y-box protein-associated acidic protein (YBAP1/C1QBP) affects the localization and cytoplasmic functions of YB-1. Sci Rep 2018; 8:6198. [PMID: 29670170 PMCID: PMC5906478 DOI: 10.1038/s41598-018-24401-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 03/26/2018] [Indexed: 01/07/2023] Open
Abstract
The Y-box proteins are multifunctional nucleic acid-binding proteins involved in various aspects of gene regulation. The founding member of the Y-box protein family, YB-1, functions as a transcription factor as well as a principal component of messenger ribonucleoprotein particles (mRNPs) in somatic cells. The nuclear level of YB-1 is well correlated with poor prognosis in many human cancers. Previously, we showed that a Y-box protein–associated acidic protein, YBAP1, which is identical to complement component 1, q subcomponent-binding protein (C1QBP, also called gC1qR, hyaluronan-binding protein 1 [HABP1] or ASF/SF2-associated protein p32), relieves translational repression by YB-1. Here we show that the nuclear localization of YB-1 harboring a point mutation in the cold shock domain was inhibited when co-expressed with YBAP1, whereas cytoplasmic accumulation of the wild-type YB-1 was not affected. We showed that YBAP1 inhibited the interaction between YB-1 and transportin 1. In the cytoplasm, YBAP1 affected the accumulation of YB-1 to processing bodies (P-bodies) and partially abrogated the mRNA stabilization by YB-1. Our results, indicating that YBAP1/C1QBP regulates the nucleo-cytoplasmic distribution of YB-1 and its cytoplasmic functions, are consistent with a model that YBAP1/C1QBP acts as an mRNP remodeling factor.
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Affiliation(s)
- Ken Matsumoto
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, RIKEN, Wako, Saitama, Japan. .,PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan. .,Molecular Entomology Laboratory, RIKEN, Wako, Saitama, Japan.
| | - Shingo Kose
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research (CPR), RIKEN, Wako, Saitama, Japan
| | - Iku Kuwahara
- Molecular Entomology Laboratory, RIKEN, Wako, Saitama, Japan
| | - Mami Yoshimura
- Molecular Entomology Laboratory, RIKEN, Wako, Saitama, Japan
| | - Naoko Imamoto
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research (CPR), RIKEN, Wako, Saitama, Japan
| | - Minoru Yoshida
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, RIKEN, Wako, Saitama, Japan
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61
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Karyopherins in cancer. Curr Opin Cell Biol 2018; 52:30-42. [PMID: 29414591 DOI: 10.1016/j.ceb.2018.01.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/08/2018] [Accepted: 01/14/2018] [Indexed: 12/16/2022]
Abstract
Malfunction of nuclear-cytoplasmic transport contributes to many diseases including cancer. Defective nuclear transport leads to changes in both the physiological levels and temporal-spatial location of tumor suppressors, proto-oncogenes and other macromolecules that in turn affect the tumorigenesis process and drug sensitivity of cancer cells. In addition to their nuclear transport functions in interphase, Karyopherin nuclear transport receptors also have important roles in mitosis and chromosomal integrity. Therefore, alterations in the expressions or regular functions of Karyopherins may have substantial effects on the course and outcome of diseases.
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62
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Lu L, Madugula V. Mechanisms of ciliary targeting: entering importins and Rabs. Cell Mol Life Sci 2018; 75:597-606. [PMID: 28852774 PMCID: PMC11105572 DOI: 10.1007/s00018-017-2629-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 08/11/2017] [Accepted: 08/16/2017] [Indexed: 12/29/2022]
Abstract
Primary cilium is a rod-like plasma membrane protrusion that plays important roles in sensing the cellular environment and initiating corresponding signaling pathways. The sensory functions of the cilium critically depend on the unique enrichment of ciliary residents, which is maintained by the ciliary diffusion barrier. It is still unclear how ciliary cargoes specifically enter the diffusion barrier and accumulate within the cilium. In this review, the organization and trafficking mechanism of the cilium are compared to those of the nucleus, which are much better understood at the moment. Though the cilium differs significantly from the nucleus in terms of molecular and cellular functions, analogous themes and principles in the membrane organization and cargo trafficking are notable between them. Therefore, knowledge in the nuclear trafficking can likely shed light on our understanding of the ciliary trafficking. Here, with a focus on membrane cargoes in mammalian cells, we briefly review various ciliary trafficking pathways from the Golgi to the periciliary membrane. Models for the subsequent import translocation across the diffusion barrier and the enrichment of cargoes within the ciliary membrane are discussed in detail. Based on recent discoveries, we propose a Rab-importin-based model in an attempt to accommodate various observations on ciliary targeting.
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Affiliation(s)
- Lei Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore.
| | - Viswanadh Madugula
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
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63
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Mackmull MT, Klaus B, Heinze I, Chokkalingam M, Beyer A, Russell RB, Ori A, Beck M. Landscape of nuclear transport receptor cargo specificity. Mol Syst Biol 2017; 13:962. [PMID: 29254951 PMCID: PMC5740495 DOI: 10.15252/msb.20177608] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Nuclear transport receptors (NTRs) recognize localization signals of cargos to facilitate their passage across the central channel of nuclear pore complexes (NPCs). About 30 different NTRs constitute different transport pathways in humans and bind to a multitude of different cargos. The exact cargo spectrum of the majority of NTRs, their specificity and even the extent to which active nucleocytoplasmic transport contributes to protein localization remains understudied because of the transient nature of these interactions and the wide dynamic range of cargo concentrations. To systematically map cargo-NTR relationships in situ, we used proximity ligation coupled to mass spectrometry (BioID). We systematically fused the engineered biotin ligase BirA* to 16 NTRs. We estimate that a considerable fraction of the human proteome is subject to active nuclear transport. We quantified the specificity and redundancy in NTR interactions and identified transport pathways for cargos. We extended the BioID method by the direct identification of biotinylation sites. This approach enabled us to identify interaction interfaces and to discriminate direct versus piggyback transport mechanisms. Data are available via ProteomeXchange with identifier PXD007976.
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Affiliation(s)
- Marie-Therese Mackmull
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Bernd Klaus
- Centre for Statistical Data Analysis, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Ivonne Heinze
- Leibniz Institute on Aging, Fritz Lipmann Institute (FLI), Jena, Germany
| | | | - Andreas Beyer
- Cellular Networks and Systems Biology, CECAD, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Robert B Russell
- Heidelberg University Biochemistry Centre & Bioquant, Heidelberg, Germany
| | - Alessandro Ori
- Leibniz Institute on Aging, Fritz Lipmann Institute (FLI), Jena, Germany
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany .,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
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Idica A, Sevrioukov EA, Zisoulis DG, Hamdorf M, Daugaard I, Kadandale P, Pedersen IM. MicroRNA miR-128 represses LINE-1 (L1) retrotransposition by down-regulating the nuclear import factor TNPO1. J Biol Chem 2017; 292:20494-20508. [PMID: 28974576 DOI: 10.1074/jbc.m117.807677] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/20/2017] [Indexed: 01/04/2023] Open
Abstract
Repetitive elements, including LINE-1 (L1), comprise approximately half of the human genome. These elements can potentially destabilize the genome by initiating their own replication and reintegration into new sites (retrotransposition). In somatic cells, transcription of L1 elements is repressed by distinct molecular mechanisms, including DNA methylation and histone modifications, to repress transcription. Under conditions of hypomethylation (e.g. in tumor cells), a window of opportunity for L1 derepression arises, and additional restriction mechanisms become crucial. We recently demonstrated that the microRNA miR-128 represses L1 activity by directly binding to L1 ORF2 RNA. In this study, we tested whether miR-128 can also control L1 activity by repressing cellular proteins important for L1 retrotransposition. We found that miR-128 targets the 3' UTR of nuclear import factor transportin 1 (TNPO1) mRNA. Manipulation of miR-128 and TNPO1 levels demonstrated that induction or depletion of TNPO1 affects L1 retrotransposition and nuclear import of an L1-ribonucleoprotein complex (using L1-encoded ORF1p as a proxy for L1-ribonucleoprotein complexes). Moreover, TNPO1 overexpression partially reversed the repressive effect of miR-128 on L1 retrotransposition. Our study represents the first description of a protein factor involved in nuclear import of the L1 element and demonstrates that miR-128 controls L1 activity in somatic cells through two independent mechanisms: direct binding to L1 RNA and regulation of a cellular factor necessary for L1 nuclear import and retrotransposition.
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Affiliation(s)
- Adam Idica
- From the Department of Molecular Biology and Biochemistry, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, California 92697
| | - Evgueni A Sevrioukov
- From the Department of Molecular Biology and Biochemistry, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, California 92697
| | - Dimitrios G Zisoulis
- From the Department of Molecular Biology and Biochemistry, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, California 92697
| | - Matthias Hamdorf
- From the Department of Molecular Biology and Biochemistry, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, California 92697
| | - Iben Daugaard
- From the Department of Molecular Biology and Biochemistry, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, California 92697
| | - Pavan Kadandale
- From the Department of Molecular Biology and Biochemistry, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, California 92697
| | - Irene M Pedersen
- From the Department of Molecular Biology and Biochemistry, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, California 92697
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65
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Sun Y, Yang Z, Wang C, Yang T, Cai C, Zhao X, Yang L, Ding P. Exploring the role of peptides in polymer-based gene delivery. Acta Biomater 2017; 60:23-37. [PMID: 28778533 DOI: 10.1016/j.actbio.2017.07.043] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/14/2017] [Accepted: 07/31/2017] [Indexed: 12/15/2022]
Abstract
Polymers are widely studied as non-viral gene vectors because of their strong DNA binding ability, capacity to carry large payload, flexibility of chemical modifications, low immunogenicity, and facile processes for manufacturing. However, high cytotoxicity and low transfection efficiency substantially restrict their application in clinical trials. Incorporating functional peptides is a promising approach to address these issues. Peptides demonstrate various functions in polymer-based gene delivery systems, such as targeting to specific cells, breaching membrane barriers, facilitating DNA condensation and release, and lowering cytotoxicity. In this review, we systematically summarize the role of peptides in polymer-based gene delivery, and elaborate how to rationally design polymer-peptide based gene delivery vectors. STATEMENT OF SIGNIFICANCE Polymers are widely studied as non-viral gene vectors, but suffer from high cytotoxicity and low transfection efficiency. Incorporating short, bioactive peptides into polymer-based gene delivery systems can address this issue. Peptides demonstrate various functions in polymer-based gene delivery systems, such as targeting to specific cells, breaching membrane barriers, facilitating DNA condensation and release, and lowering cytotoxicity. In this review, we highlight the peptides' roles in polymer-based gene delivery, and elaborate how to utilize various functional peptides to enhance the transfection efficiency of polymers. The optimized peptide-polymer vectors should be able to alter their structures and functions according to biological microenvironments and utilize inherent intracellular pathways of cells, and consequently overcome the barriers during gene delivery to enhance transfection efficiency.
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Affiliation(s)
- Yanping Sun
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Zhen Yang
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Chunxi Wang
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Tianzhi Yang
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, Husson University, Bangor, ME, USA
| | - Cuifang Cai
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Xiaoyun Zhao
- Department of Microbiology and Cell Biology, School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Li Yang
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, China.
| | - Pingtian Ding
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, China.
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66
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Lai KKY, Kweon SM, Chi F, Hwang E, Kabe Y, Higashiyama R, Qin L, Yan R, Wu RP, Lai K, Fujii N, French S, Xu J, Wang JY, Murali R, Mishra L, Lee JS, Ntambi JM, Tsukamoto H. Stearoyl-CoA Desaturase Promotes Liver Fibrosis and Tumor Development in Mice via a Wnt Positive-Signaling Loop by Stabilization of Low-Density Lipoprotein-Receptor-Related Proteins 5 and 6. Gastroenterology 2017; 152:1477-1491. [PMID: 28143772 PMCID: PMC5406249 DOI: 10.1053/j.gastro.2017.01.021] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 01/09/2017] [Accepted: 01/17/2017] [Indexed: 12/14/2022]
Abstract
BACKGROUND & AIMS Stearoyl-CoA desaturase (SCD) synthesizes monounsaturated fatty acids (MUFAs) and has been associated with the development of metabolic syndrome, tumorigenesis, and stem cell characteristics. We investigated whether and how SCD promotes liver fibrosis and tumor development in mice. METHODS Rodent primary hepatic stellate cells (HSCs), mouse liver tumor-initiating stem cell-like cells (TICs), and human hepatocellular carcinoma (HCC) cell lines were exposed to Wnt signaling inhibitors and changes in gene expression patterns were analyzed. We assessed the functions of SCD by pharmacologic and conditional genetic manipulation in mice with hepatotoxic or cholestatic induction of liver fibrosis, orthotopic transplants of TICs, or liver tumors induced by administration of diethyl nitrosamine. We performed bioinformatic analyses of SCD expression in HCC vs nontumor liver samples collected from patients, and correlated levels with HCC stage and patient mortality. We performed nano-bead pull-down assays, liquid chromatography-mass spectrometry, computational modeling, and ribonucleoprotein immunoprecipitation analyses to identify MUFA-interacting proteins. We examined the effects of SCD inhibition on Wnt signaling, including the expression and stability of low-density lipoprotein-receptor-related proteins 5 and 6 (LRP5 and LRP6), by immunoblot and quantitative polymerase chain reaction analyses. RESULTS SCD was overexpressed in activated HSC and HCC cells from patients; levels of SCD messenger RNA (mRNA) correlated with HCC stage and patient survival time. In rodent HSCs and TICs, the Wnt effector β-catenin increased sterol regulatory element binding protein 1-dependent transcription of Scd, and β-catenin in return was stabilized by MUFAs generated by SCD. This loop required MUFA inhibition of binding of Ras-related nuclear protein 1 (Ran1) to transportin 1 and reduced nuclear import of elav-like protein 1 (HuR), increasing cytosolic levels of HuR and HuR-mediated stabilization of mRNAs encoding LRP5 and LRP6. Genetic disruption of Scd and pharmacologic inhibitors of SCD reduced HSC activation and TIC self-renewal and attenuated liver fibrosis and tumorigenesis in mice. Conditional disruption of Scd2 in activated HSCs prevented growth of tumors from TICs and reduced the formation of diethyl nitrosamine-induced liver tumors in mice. CONCLUSIONS In rodent HSCs and TICs, we found SCD expression to be regulated by Wnt-β-catenin signaling, and MUFAs produced by SCD provided a forward loop to amplify Wnt signaling via stabilization of Lrp5 and Lrp6 mRNAs, contributing to liver fibrosis and tumor growth. SCD expressed by HSCs promoted liver tumor development in mice. Components of the identified loop linking HSCs and TICs might be therapeutic targets for liver fibrosis and tumors.
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Affiliation(s)
- Keane K Y Lai
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California
| | - Soo-Mi Kweon
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California
| | - Feng Chi
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California
| | - Edward Hwang
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California
| | - Yasuaki Kabe
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
| | - Reiichi Higashiyama
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California
| | - Lan Qin
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California
| | - Rui Yan
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California
| | - Raymond P Wu
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California
| | - Keith Lai
- Department of Anatomic Pathology, Cleveland Clinic, Cleveland, Ohio
| | - Naoaki Fujii
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Samuel French
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California; Harbor-University of California Los Angeles Medical Center, Torrance, California
| | - Jun Xu
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California
| | - Jian-Ying Wang
- Departments of Surgery and Pathology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ramachandran Murali
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Lopa Mishra
- Department of Surgery and Cancer Center, George Washington University, Washington, District of Columbia
| | - Ju-Seog Lee
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, Texas
| | - James M Ntambi
- Departments of Biochemistry and Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Hidekazu Tsukamoto
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, University of Southern California, Los Angeles, California; Department of Veterans Affairs, Greater Los Angeles Healthcare System, Los Angeles, California.
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67
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Funabashi T, Katoh Y, Michisaka S, Terada M, Sugawa M, Nakayama K. Ciliary entry of KIF17 is dependent on its binding to the IFT-B complex via IFT46-IFT56 as well as on its nuclear localization signal. Mol Biol Cell 2017; 28:624-633. [PMID: 28077622 PMCID: PMC5328621 DOI: 10.1091/mbc.e16-09-0648] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 12/27/2016] [Accepted: 01/03/2017] [Indexed: 12/21/2022] Open
Abstract
Cilia function as cellular antennae to sense and transduce extracellular signals. A number of proteins are specifically localized in cilia. Anterograde and retrograde ciliary protein trafficking are mediated by the IFT-B and IFT-A complexes in concert with kinesin-2 and dynein-2 motors, respectively. However, the role of KIF17, a homodimeric kinesin-2 protein, in protein trafficking has not been fully understood in vertebrate cilia. In this study, we demonstrated, by using the visible immunoprecipitation assay, that KIF17 interacts with the IFT46-IFT56 dimer in the IFT-B complex through its C-terminal sequence located immediately upstream of the nuclear localization signal (NLS). We then showed that KIF17 reaches the ciliary tip independently of its motor domain and requires IFT-B binding for its entry into cilia rather than for its intraciliary trafficking. We further showed that KIF17 ciliary entry depends not only on its binding to IFT-B but also on its NLS, to which importin α proteins bind. Taking the results together, we conclude that in mammalian cells, KIF17 is dispensable for ciliogenesis and IFT-B trafficking but requires IFT-B, as well as its NLS, for its ciliary entry across the permeability barrier located at the ciliary base.
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Affiliation(s)
- Teruki Funabashi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Yohei Katoh
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Saki Michisaka
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Masaya Terada
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Maho Sugawa
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Kazuhisa Nakayama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
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68
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Kimura M, Morinaka Y, Imai K, Kose S, Horton P, Imamoto N. Extensive cargo identification reveals distinct biological roles of the 12 importin pathways. eLife 2017; 6:e21184. [PMID: 28117667 PMCID: PMC5305215 DOI: 10.7554/elife.21184] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/17/2017] [Indexed: 12/31/2022] Open
Abstract
Vast numbers of proteins are transported into and out of the nuclei by approximately 20 species of importin-β family nucleocytoplasmic transport receptors. However, the significance of the multiple parallel transport pathways that the receptors constitute is poorly understood because only limited numbers of cargo proteins have been reported. Here, we identified cargo proteins specific to the 12 species of human import receptors with a high-throughput method that employs stable isotope labeling with amino acids in cell culture, an in vitro reconstituted transport system, and quantitative mass spectrometry. The identified cargoes illuminated the manner of cargo allocation to the receptors. The redundancies of the receptors vary widely depending on the cargo protein. Cargoes of the same receptor are functionally related to one another, and the predominant protein groups in the cargo cohorts differ among the receptors. Thus, the receptors are linked to distinct biological processes by the nature of their cargoes.
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Affiliation(s)
| | | | - Kenichiro Imai
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Shingo Kose
- Cellular Dynamics Laboratory, RIKEN, Wako, Japan
| | - Paul Horton
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
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69
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Wenzel M, Schüle M, Casanovas S, Strand D, Strand S, Winter J. Identification of a classic nuclear localization signal at the N terminus that regulates the subcellular localization of Rbfox2 isoforms during differentiation of NMuMG and P19 cells. FEBS Lett 2016; 590:4453-4460. [PMID: 27859055 DOI: 10.1002/1873-3468.12492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 11/07/2016] [Indexed: 01/02/2023]
Abstract
Nuclear localization of the alternative splicing factor Rbfox2 is achieved by a C-terminal nuclear localization signal (NLS) which can be excluded from some Rbfox2 isoforms by alternative splicing. While this predicts nuclear and cytoplasmic localization, Rbfox2 is exclusively nuclear in some cell types. Here, we identify a second NLS in the N terminus of Rbfox2 isoform 1A that is not included in Rbfox2 isoform 1F. Rbfox2 1A isoforms lacking the C-terminal NLS are nuclear, whereas equivalent 1F isoforms are cytoplasmic. A shift in Rbfox2 expression toward cytoplasmic 1F isoforms occurs during epithelial to mesenchymal transition (EMT) and could be important in regulating the activity and function of Rbfox2.
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Affiliation(s)
- Manuel Wenzel
- Institute of Human Genetics, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Martin Schüle
- Institute of Human Genetics, University Medical Center, Johannes Gutenberg University Mainz, Germany.,Focus Program of Translational Neurosciences, Johannes Gutenberg University Mainz, Germany
| | - Sonia Casanovas
- Institute of Human Genetics, University Medical Center, Johannes Gutenberg University Mainz, Germany.,Focus Program of Translational Neurosciences, Johannes Gutenberg University Mainz, Germany
| | - Dennis Strand
- First Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Susanne Strand
- First Department of Internal Medicine, University Medical Center, Johannes Gutenberg University Mainz, Germany
| | - Jennifer Winter
- Institute of Human Genetics, University Medical Center, Johannes Gutenberg University Mainz, Germany.,Focus Program of Translational Neurosciences, Johannes Gutenberg University Mainz, Germany
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Mordovkina DA, Kim ER, Buldakov IA, Sorokin AV, Eliseeva IA, Lyabin DN, Ovchinnikov LP. Transportin-1-dependent YB-1 nuclear import. Biochem Biophys Res Commun 2016; 480:629-634. [DOI: 10.1016/j.bbrc.2016.10.107] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 10/25/2016] [Indexed: 11/24/2022]
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71
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Madugula V, Lu L. A ternary complex comprising transportin1, Rab8 and the ciliary targeting signal directs proteins to ciliary membranes. J Cell Sci 2016; 129:3922-3934. [PMID: 27633000 PMCID: PMC5087665 DOI: 10.1242/jcs.194019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/31/2016] [Indexed: 12/13/2022] Open
Abstract
The sensory functions of cilia are dependent on the enrichment of cilium-resident proteins. Although it is known that ciliary targeting signals (CTSs) specifically target ciliary proteins to cilia, it is still unclear how CTSs facilitate the entry and retention of cilium-resident proteins at the molecular level. We found that non-ciliary membrane reporters can passively diffuse into cilia through the lateral transport pathway, and the translocation of membrane reporters through the ciliary diffusion barrier is facilitated by importin binding motifs and domains. Screening known CTSs of ciliary membrane residents uncovered that fibrocystin, photoreceptor retinol dehydrogenase, rhodopsin and retinitis pigmentosa 2 interact with transportin1 (TNPO1) through previously identified CTSs. We further discovered that a new ternary complex, comprising TNPO1, Rab8 and a CTS, can assemble or disassemble under the guanine nucleotide exchange activity of Rab8. Our study suggests a new mechanism in which the TNPO1-Rab8-CTS complex mediates selective entry into and retention of cargos within cilia.
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Affiliation(s)
- Viswanadh Madugula
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore
| | - Lei Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore
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72
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Soniat M, Chook YM. Karyopherin-β2 Recognition of a PY-NLS Variant that Lacks the Proline-Tyrosine Motif. Structure 2016; 24:1802-1809. [PMID: 27618664 DOI: 10.1016/j.str.2016.07.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 07/20/2016] [Accepted: 07/22/2016] [Indexed: 10/21/2022]
Abstract
Karyopherin-β2 or Transportin-1 binds proline-tyrosine nuclear localization signals (PY-NLSs) in its cargos. PY-NLSs are described by structural disorder, overall positive charge, and binding epitopes composed of an N-terminal hydrophobic or basic motif and a C-terminal R-X2-5P-Y motif. The N-terminal tail of histone H3 binds Kapβ2 with high affinity but does not contain a recognizable PY-NLS. The crystal structure of the Kapβ2-H3 tail shows residues 11-27 of H3 binding to the PY-NLS site of Kapβ2. H3 residues 11TGGKAPRK18 bind the site for PY-NLS Epitope 1 (N-terminal hydrophobic/basic motif), which is most important for Kapβ2-binding. H3 residue Arg26 occupies the PY-NLS Epitope 2 position (usually arginine of R-X2-5P-Y) but PY-NLS Epitope 3 (proline-tyrosine motif) is missing in the H3 tail. Histone H3 thus provides an example of a PY-NLS variant with no proline-tyrosine or homologous proline-hydrophobic motif. The H3 tail uses a very strong Epitope 1 to compensate for loss of the often-conserved proline-tyrosine epitope.
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Affiliation(s)
- Michael Soniat
- Department of Pharmacology, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Yuh Min Chook
- Department of Pharmacology, University of Texas Southwestern, Dallas, TX 75390, USA.
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Prpar Mihevc S, Darovic S, Kovanda A, Bajc Česnik A, Župunski V, Rogelj B. Nuclear trafficking in amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Brain 2016; 140:13-26. [PMID: 27497493 DOI: 10.1093/brain/aww197] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis and frontotemporal lobar degeneration are two ends of a phenotypic spectrum of disabling, relentlessly progressive and ultimately fatal diseases. A key characteristic of both conditions is the presence of TDP-43 (encoded by TARDBP) or FUS immunoreactive cytoplasmic inclusions in neuronal and glial cells. This cytoplasmic mislocalization of otherwise predominantly nuclear RNA binding proteins implies a perturbation of the nucleocytoplasmic shuttling as a possible event in the pathogenesis. Compromised nucleocytoplasmic shuttling has recently also been associated with a hexanucleotide repeat expansion mutation in C9orf72, which is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal lobar degeneration, and leads to accumulation of cytoplasmic TDP-43 inclusions. Mutation in C9orf72 may disrupt nucleocytoplasmic shuttling on the level of C9ORF72 protein, the transcribed hexanucleotide repeat RNA, and/or dipeptide repeat proteins translated form the hexanucleotide repeat RNA. These defects of nucleocytoplasmic shuttling may therefore, constitute the common ground of the underlying disease mechanisms in different molecular subtypes of amyotrophic lateral sclerosis and frontotemporal lobar degeneration.
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Affiliation(s)
- Sonja Prpar Mihevc
- 1 Department of Biotechnology, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Simona Darovic
- 1 Department of Biotechnology, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Anja Kovanda
- 1 Department of Biotechnology, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Ana Bajc Česnik
- 1 Department of Biotechnology, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Vera Župunski
- 2 Faculty of Chemistry and Chemical Technology, Večna pot 113, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Boris Rogelj
- 1 Department of Biotechnology, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia .,2 Faculty of Chemistry and Chemical Technology, Večna pot 113, University of Ljubljana, SI-1000 Ljubljana, Slovenia.,3 Biomedical Research Institute BRIS, Puhova 10, SI-1000 Ljubljana, Slovenia
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74
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Sun Y, Xian L, Xing H, Yu J, Yang Z, Yang T, Yang L, Ding P. Factors influencing the nuclear targeting ability of nuclear localization signals. J Drug Target 2016; 24:927-933. [DOI: 10.1080/1061186x.2016.1184273] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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75
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Vaidyanathan S, Thangavelu PU, Duijf PHG. Overexpression of Ran GTPase Components Regulating Nuclear Export, but not Mitotic Spindle Assembly, Marks Chromosome Instability and Poor Prognosis in Breast Cancer. Target Oncol 2016; 11:677-686. [DOI: 10.1007/s11523-016-0432-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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76
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Yan B, Wang X, Wang Z, Chen N, Mu C, Mao K, Han L, Zhang W, Liu H. Identification of potential cargo proteins of transportin protein AtTRN1 in Arabidopsis thaliana. PLANT CELL REPORTS 2016; 35:629-640. [PMID: 26650834 DOI: 10.1007/s00299-015-1908-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 10/26/2015] [Accepted: 11/17/2015] [Indexed: 06/05/2023]
Abstract
We identified 23 novel proteins that can interact with At TRN1. These proteins are potential candidates of At TRN1 cargo proteins, which will facilitate our comprehending of At TRN1 functions in Arabidopsis. Tranportin 1 (TRN1) carries out the nucleo-cytoplasmic transport of many proteins, thereby ensuring that each of them is delivered to the right compartment for its proper function. These cargo proteins involved in lots of important processes, such as alternative pre-mRNA splicing, transcriptional regulation, and protein translation. Current understanding of cargo proteins transported by Arabidopsis thaliana transportin 1 (AtTRN1) is limited. Here, first we employed the yeast two-hybrid (Y2H) screening to identify proteins that can interact with AtTRN1 in Arabidopsis, and 12 novel proteins were found. Searching for PY-NLS motif in these 12 proteins suggested that no typical PY-NLS motif was present. We next investigated the specific motifs that will mediate the interactions in these sequences, and found that thirteen truncated fragments interacted with AtTRN1, containing 8 acidic and 5 basic fragments, respectively. We also searched the Arabidopsis proteome for homologs of cargo proteins of yeast Kapl04p and mammalian Kapβ2, and PY-NLS motif-containing proteins. Among these proteins, 11 were identified to interact with AtTRN1. The interactions between all the 23 proteins and AtTRN1 were confirmed by both Y2H and bimolecular fluorescence complementation (BiFC) assays. Our results show that AtTRN1 recognizes a broad spectrum of proteins having diverse functions, which will potentially be the cargoes of AtTRN1. Taken together, these results demonstrate the feasibility and potential power of these methods to identify cargo proteins of AtTRN1, and represent a primary and significant step in interpretation of AtTRN1 functionalities.
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Affiliation(s)
- Bo Yan
- Ministry Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Xiaoning Wang
- Ministry Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Zhenyu Wang
- Ministry Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Ni Chen
- Ministry Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Changjun Mu
- Ministry Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Kaili Mao
- Ministry Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Lirong Han
- Ministry Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Wei Zhang
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, People's Republic of China
| | - Heng Liu
- Ministry Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.
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77
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Musinova YR, Sheval EV, Dib C, Germini D, Vassetzky YS. Functional roles of HIV-1 Tat protein in the nucleus. Cell Mol Life Sci 2016; 73:589-601. [PMID: 26507246 PMCID: PMC11108392 DOI: 10.1007/s00018-015-2077-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 09/01/2015] [Accepted: 10/16/2015] [Indexed: 02/06/2023]
Abstract
Human immunodeficiency virus-1 (HIV-1) Tat protein is one of the most important regulatory proteins for viral gene expression in the host cell and can modulate different cellular processes. In addition, Tat is secreted by the infected cell and can be internalized by neighboring cells; therefore, it affects both infected and uninfected cells. Tat can modulate cellular processes by interacting with different cellular structures and signaling pathways. In the nucleus, Tat might be localized either in the nucleoplasm or the nucleolus depending on its concentration. Here we review the distinct functions of Tat in the nucleoplasm and the nucleolus in connection with viral infection and HIV-induced oncogenesis.
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Affiliation(s)
- Yana R Musinova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
| | - Eugene V Sheval
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
| | - Carla Dib
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805, Villejuif, France
| | - Diego Germini
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805, Villejuif, France
| | - Yegor S Vassetzky
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia.
- LIA 1066 French-Russian Joint Cancer Research Laboratory, 94805, Villejuif, France.
- UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, 94805, Villejuif, France.
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78
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Roggero VR, Zhang J, Parente LE, Doshi Y, Dziedzic RC, McGregor EL, Varjabedian AD, Schad SE, Bondzi C, Allison LA. Nuclear import of the thyroid hormone receptor α1 is mediated by importin 7, importin β1, and adaptor importin α1. Mol Cell Endocrinol 2016; 419:185-97. [PMID: 26525414 PMCID: PMC4684427 DOI: 10.1016/j.mce.2015.10.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 10/20/2015] [Accepted: 10/20/2015] [Indexed: 01/27/2023]
Abstract
The thyroid hormone receptor α1 (TRα1) is a nuclear receptor for thyroid hormone that shuttles rapidly between the nucleus and cytoplasm. Our prior studies showed that nuclear import of TRα1 is directed by two nuclear localization signals, one in the N-terminal A/B domain and the other in the hinge domain. Here, we showed using in vitro nuclear import assays that TRα1 nuclear localization is temperature and energy-dependent and can be reconstituted by the addition of cytosol. In HeLa cells expressing green fluorescent protein (GFP)-tagged TRα1, knockdown of importin 7, importin β1 and importin α1 by RNA interference, or treatment with an importin β1-specific inhibitor, significantly reduced nuclear localization of TRα1, while knockdown of other importins had no effect. Coimmunoprecipitation assays confirmed that TRα1 interacts with importin 7, as well as importin β1 and the adapter importin α1, suggesting that TRα1 trafficking into the nucleus is mediated by two distinct pathways.
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Affiliation(s)
- Vincent R Roggero
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Jibo Zhang
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Laura E Parente
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Yazdi Doshi
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Rose C Dziedzic
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Emma L McGregor
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Arev D Varjabedian
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Sara E Schad
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Cornelius Bondzi
- Department of Biological Sciences, Hampton University, Hampton, VA, 23668, USA
| | - Lizabeth A Allison
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA.
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79
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Abstract
The Karyopherin-β family of proteins mediates nuclear transport of macromolecules. Nuclear versus cytoplasmic localization of proteins is often suggested by the presence of NLSs (nuclear localization signals) or NESs (nuclear export signals). Import-Karyopherin-βs or Importins bind to NLSs in their protein cargos to transport them through nuclear pore complexes into the nucleus. Until recently, only two classes of NLS had been biochemically and structurally characterized: the classical NLS, which is recognized by the Importin-α/β heterodimer and the PY-NLS (proline-tyrosine NLS), which is recognized by Karyopherin-β2 or Transportin-1. Structures of two other Karyopherin-βs, Kap121 and Transportin-SR2, in complex with their respective cargos were reported for the first time recently, revealing two new distinct classes of NLSs. The present paper briefly describes the classical NLS, reviews recent literature on the PY-NLS and provides in-depth reviews of the two newly discovered classes of NLSs that bind Kap121p and Transportin-SR respectively.
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80
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Bauer NC, Doetsch PW, Corbett AH. Mechanisms Regulating Protein Localization. Traffic 2015; 16:1039-61. [PMID: 26172624 DOI: 10.1111/tra.12310] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 07/08/2015] [Accepted: 07/08/2015] [Indexed: 12/23/2022]
Abstract
Cellular functions are dictated by protein content and activity. There are numerous strategies to regulate proteins varying from modulating gene expression to post-translational modifications. One commonly used mode of regulation in eukaryotes is targeted localization. By specifically redirecting the localization of a pool of existing protein, cells can achieve rapid changes in local protein function. Eukaryotic cells have evolved elegant targeting pathways to direct proteins to the appropriate cellular location or locations. Here, we provide a general overview of these localization pathways, with a focus on nuclear and mitochondrial transport, and present a survey of the evolutionarily conserved regulatory strategies identified thus far. We end with a description of several specific examples of proteins that exploit localization as an important mode of regulation.
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Affiliation(s)
- Nicholas C Bauer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.,Current address: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Paul W Doetsch
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Anita H Corbett
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
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81
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Subramanian KS, Dziedzic RC, Nelson HN, Stern ME, Roggero VR, Bondzi C, Allison LA. Multiple exportins influence thyroid hormone receptor localization. Mol Cell Endocrinol 2015; 411:86-96. [PMID: 25911113 PMCID: PMC4458229 DOI: 10.1016/j.mce.2015.04.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 04/15/2015] [Accepted: 04/15/2015] [Indexed: 12/17/2022]
Abstract
The thyroid hormone receptor (TR) undergoes nucleocytoplasmic shuttling and regulates target genes involved in metabolism and development. Previously, we showed that TR follows a CRM1/calreticulin-mediated nuclear export pathway. However, two lines of evidence suggest TR also follows another pathway: export is only partially blocked by leptomycin B (LMB), a CRM1-specific inhibitor; and we identified nuclear export signals in TR that are LMB-resistant. To determine whether other exportins are involved in TR shuttling, we used RNA interference and fluorescence recovery after photobleaching shuttling assays in transfected cells. Knockdown of exportins 4, 5, and 7 altered TR shuttling dynamics, and when exportins 5 and 7 were overexpressed, TR distribution shifted toward the cytosol. To further assess the effects of exportin overexpression, we examined transactivation of a TR-responsive reporter gene. Our data indicate that multiple exportins influence TR localization, highlighting a fine balance of nuclear import, retention, and export that modulates TR function.
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Affiliation(s)
- Kelly S Subramanian
- Department of Biology, College of William and Mary, Williamsburg, Virginia 23185, USA
| | - Rose C Dziedzic
- Department of Biology, College of William and Mary, Williamsburg, Virginia 23185, USA
| | - Hallie N Nelson
- Department of Biology, College of William and Mary, Williamsburg, Virginia 23185, USA
| | - Mary E Stern
- Department of Biology, College of William and Mary, Williamsburg, Virginia 23185, USA
| | - Vincent R Roggero
- Department of Biology, College of William and Mary, Williamsburg, Virginia 23185, USA
| | - Cornelius Bondzi
- Department of Biological Sciences, Hampton University, Hampton, Virginia 23668, USA
| | - Lizabeth A Allison
- Department of Biology, College of William and Mary, Williamsburg, Virginia 23185, USA.
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82
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Forbes DJ, Travesa A, Nord MS, Bernis C. Reprint of "Nuclear transport factors: global regulation of mitosis". Curr Opin Cell Biol 2015. [PMID: 26196321 DOI: 10.1016/j.ceb.2015.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The unexpected repurposing of nuclear transport proteins from their function in interphase to an equally vital and very different set of functions in mitosis was very surprising. The multi-talented cast when first revealed included the import receptors, importin alpha and beta, the small regulatory GTPase RanGTP, and a subset of nuclear pore proteins. In this review, we report that recent years have revealed new discoveries in each area of this expanding story in vertebrates: (a) The cast of nuclear import receptors playing a role in mitotic spindle regulation has expanded: both transportin, a nuclear import receptor, and Crm1/Xpo1, an export receptor, are involved in different aspects of spindle assembly. Importin beta and transportin also regulate nuclear envelope and pore assembly. (b) The role of nucleoporins has grown to include recruiting the key microtubule nucleator – the γ-TuRC complex – and the exportin Crm1 to the mitotic kinetochores of humans. Together they nucleate microtubule formation from the kinetochores toward the centrosomes. (c) New research finds that the original importin beta/RanGTP team have been further co-opted by evolution to help regulate other cellular and organismal activities, ranging from the actual positioning of the spindle within the cell perimeter, to regulation of a newly discovered spindle microtubule branching activity, to regulation of the interaction of microtubule structures with specific actin structures. (d) Lastly, because of the multitudinous roles of karyopherins throughout the cell cycle, a recent large push toward testing their potential as chemotherapeutic targets has begun to yield burgeoning progress in the clinic.
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Affiliation(s)
- Douglass J Forbes
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, Room 2124A Pacific Hall, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, United States.
| | - Anna Travesa
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, Room 2124A Pacific Hall, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, United States
| | - Matthew S Nord
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, Room 2124A Pacific Hall, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, United States
| | - Cyril Bernis
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, Room 2124A Pacific Hall, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, United States
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83
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Chou CC, Alexeeva OM, Yamada S, Pribadi A, Zhang Y, Mo B, Williams KR, Zarnescu DC, Rossoll W. PABPN1 suppresses TDP-43 toxicity in ALS disease models. Hum Mol Genet 2015; 24:5154-73. [PMID: 26130692 DOI: 10.1093/hmg/ddv238] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/22/2015] [Indexed: 12/13/2022] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is a major disease protein in amyotrophic lateral sclerosis (ALS) and related neurodegenerative diseases. Both the cytoplasmic accumulation of toxic ubiquitinated and hyperphosphorylated TDP-43 fragments and the loss of normal TDP-43 from the nucleus may contribute to the disease progression by impairing normal RNA and protein homeostasis. Therefore, both the removal of pathological protein and the rescue of TDP-43 mislocalization may be critical for halting or reversing TDP-43 proteinopathies. Here, we report poly(A)-binding protein nuclear 1 (PABPN1) as a novel TDP-43 interaction partner that acts as a potent suppressor of TDP-43 toxicity. Overexpression of full-length PABPN1 but not a truncated version lacking the nuclear localization signal protects from pathogenic TDP-43-mediated toxicity, promotes the degradation of pathological TDP-43 and restores normal solubility and nuclear localization of endogenous TDP-43. Reduced levels of PABPN1 enhances the phenotypes in several cell culture and Drosophila models of ALS and results in the cytoplasmic mislocalization of TDP-43. Moreover, PABPN1 rescues the dysregulated stress granule (SG) dynamics and facilitates the removal of persistent SGs in TDP-43-mediated disease conditions. These findings demonstrate a role for PABPN1 in rescuing several cytopathological features of TDP-43 proteinopathy by increasing the turnover of pathologic proteins.
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Affiliation(s)
- Ching-Chieh Chou
- Department of Cell Biology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Shizuka Yamada
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA and
| | - Amy Pribadi
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA and
| | - Yi Zhang
- Department of Cell Biology, Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bi Mo
- Department of Cell Biology
| | | | - Daniela C Zarnescu
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA and
| | - Wilfried Rossoll
- Department of Cell Biology, Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA 30322, USA,
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84
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Hwang B, McCool K, Wan J, Wuerzberger-Davis SM, Young EWK, Choi EY, Cingolani G, Weaver BA, Miyamoto S. IPO3-mediated Nonclassical Nuclear Import of NF-κB Essential Modulator (NEMO) Drives DNA Damage-dependent NF-κB Activation. J Biol Chem 2015; 290:17967-17984. [PMID: 26060253 DOI: 10.1074/jbc.m115.645960] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Indexed: 11/06/2022] Open
Abstract
Activation of IκB kinase (IKK) and NF-κB by genotoxic stresses modulates apoptotic responses and production of inflammatory mediators, thereby contributing to therapy resistance and premature aging. We previously reported that genotoxic agents induce nuclear localization of NF-κB essential modulator (NEMO) via an undefined mechanism to arbitrate subsequent DNA damage-dependent IKK/NF-κB signaling. Here we show that a nonclassical nuclear import pathway via IPO3 (importin 3, transportin 2) mediates stress-induced NEMO nuclear translocation. We found putative nuclear localization signals in NEMO whose mutations disrupted stress-inducible nuclear translocation of NEMO and IKK/NF-κB activation in stably reconstituted NEMO-deficient cells. RNAi screening of both importin α and β family members, as well as co-immunoprecipitation analyses, revealed that a nonclassical importin β family member, IPO3, was the only importin that was able to associate with NEMO and whose reduced expression prevented genotoxic stress-induced NEMO nuclear translocation, IKK/NF-κB activation, and inflammatory cytokine transcription. Recombinant IPO3 interacted with recombinant NEMO but not the nuclear localization signal mutant version and induced nuclear import of NEMO in digitonin-permeabilized cells. We also provide evidence that NEMO is disengaged from IKK complex following genotoxic stress induction. Thus, the IPO3 nuclear import pathway is an early and crucial determinant of the IKK/NF-κB signaling arm of the mammalian DNA damage response.
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Affiliation(s)
- Byounghoon Hwang
- Department of Oncology, University of Wisconsin, Madison, Wisconsin
| | - Kevin McCool
- Department of Oncology, University of Wisconsin, Madison, Wisconsin; Molecular and Cellular Pharmacology Program, University of Wisconsin, Madison, Wisconsin
| | - Jun Wan
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin
| | - Shelly M Wuerzberger-Davis
- Department of Oncology, University of Wisconsin, Madison, Wisconsin; University of Wisconsin Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin
| | - Edmond W K Young
- Department of Mechanical and Industrial Engineering and Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Eun Young Choi
- Department of Oncology, University of Wisconsin, Madison, Wisconsin
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Beth A Weaver
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin; University of Wisconsin Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin
| | - Shigeki Miyamoto
- Department of Oncology, University of Wisconsin, Madison, Wisconsin; University of Wisconsin Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin.
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85
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Forbes DJ, Travesa A, Nord MS, Bernis C. Nuclear transport factors: global regulation of mitosis. Curr Opin Cell Biol 2015; 35:78-90. [PMID: 25982429 DOI: 10.1016/j.ceb.2015.04.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/01/2015] [Accepted: 04/17/2015] [Indexed: 12/22/2022]
Abstract
The unexpected repurposing of nuclear transport proteins from their function in interphase to an equally vital and very different set of functions in mitosis was very surprising. The multi-talented cast when first revealed included the import receptors, importin alpha and beta, the small regulatory GTPase RanGTP, and a subset of nuclear pore proteins. In this review, we report that recent years have revealed new discoveries in each area of this expanding story in vertebrates: (a) The cast of nuclear import receptors playing a role in mitotic spindle regulation has expanded: both transportin, a nuclear import receptor, and Crm1/Xpo1, an export receptor, are involved in different aspects of spindle assembly. Importin beta and transportin also regulate nuclear envelope and pore assembly. (b) The role of nucleoporins has grown to include recruiting the key microtubule nucleator - the γ-TuRC complex - and the exportin Crm1 to the mitotic kinetochores of humans. Together they nucleate microtubule formation from the kinetochores toward the centrosomes. (c) New research finds that the original importin beta/RanGTP team have been further co-opted by evolution to help regulate other cellular and organismal activities, ranging from the actual positioning of the spindle within the cell perimeter, to regulation of a newly discovered spindle microtubule branching activity, to regulation of the interaction of microtubule structures with specific actin structures. (d) Lastly, because of the multitudinous roles of karyopherins throughout the cell cycle, a recent large push toward testing their potential as chemotherapeutic targets has begun to yield burgeoning progress in the clinic.
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Affiliation(s)
- Douglass J Forbes
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, Room 2124A Pacific Hall, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, United States.
| | - Anna Travesa
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, Room 2124A Pacific Hall, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, United States
| | - Matthew S Nord
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, Room 2124A Pacific Hall, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, United States
| | - Cyril Bernis
- Section of Cell and Developmental Biology, Division of Biological Sciences 0347, Room 2124A Pacific Hall, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0347, United States
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