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Tilliole P, Fix S, Godin JD. hnRNPs: roles in neurodevelopment and implication for brain disorders. Front Mol Neurosci 2024; 17:1411639. [PMID: 39086926 PMCID: PMC11288931 DOI: 10.3389/fnmol.2024.1411639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 06/17/2024] [Indexed: 08/02/2024] Open
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) constitute a family of multifunctional RNA-binding proteins able to process nuclear pre-mRNAs into mature mRNAs and regulate gene expression in multiple ways. They comprise at least 20 different members in mammals, named from A (HNRNP A1) to U (HNRNP U). Many of these proteins are components of the spliceosome complex and can modulate alternative splicing in a tissue-specific manner. Notably, while genes encoding hnRNPs exhibit ubiquitous expression, increasing evidence associate these proteins to various neurodevelopmental and neurodegenerative disorders, such as intellectual disability, epilepsy, microcephaly, amyotrophic lateral sclerosis, or dementias, highlighting their crucial role in the central nervous system. This review explores the evolution of the hnRNPs family, highlighting the emergence of numerous new members within this family, and sheds light on their implications for brain development.
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Affiliation(s)
- Pierre Tilliole
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, IGBMC, Illkirch, France
- Centre National de la Recherche Scientifique, CNRS, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, INSERM, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
| | - Simon Fix
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, IGBMC, Illkirch, France
- Centre National de la Recherche Scientifique, CNRS, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, INSERM, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
| | - Juliette D. Godin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, IGBMC, Illkirch, France
- Centre National de la Recherche Scientifique, CNRS, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, INSERM, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
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2
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Lu J, Ge P, Sawaya MR, Hughes MP, Boyer DR, Cao Q, Abskharon R, Cascio D, Tayeb-Fligelman E, Eisenberg DS. Cryo-EM structures of the D290V mutant of the hnRNPA2 low-complexity domain suggests how D290V affects phase separation and aggregation. J Biol Chem 2024; 300:105531. [PMID: 38072051 PMCID: PMC10844680 DOI: 10.1016/j.jbc.2023.105531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/08/2023] [Accepted: 11/20/2023] [Indexed: 02/02/2024] Open
Abstract
Heterogeneous nuclear ribonucleoprotein A2 (hnRNPA2) is a human ribonucleoprotein that transports RNA to designated locations for translation via its ability to phase separate. Its mutated form, D290V, is implicated in multisystem proteinopathy known to afflict two families, mainly with myopathy and Paget's disease of bone. Here, we investigate this mutant form of hnRNPA2 by determining cryo-EM structures of the recombinant D290V low complexity domain. We find that the mutant form of hnRNPA2 differs from the WT fibrils in four ways. In contrast to the WT fibrils, the PY-nuclear localization signals in the fibril cores of all three mutant polymorphs are less accessible to chaperones. Also, the mutant fibrils are more stable than WT fibrils as judged by phase separation, thermal stability, and energetic calculations. Similar to other pathogenic amyloids, the mutant fibrils are polymorphic. Thus, these structures offer evidence to explain how a D-to-V missense mutation diverts the assembly of reversible, functional amyloid-like fibrils into the assembly of pathogenic amyloid, and may shed light on analogous conversions occurring in other ribonucleoproteins that lead to neurological diseases such as amyotrophic lateral sclerosis and frontotemporal dementia.
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Affiliation(s)
- Jiahui Lu
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Peng Ge
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Michael R Sawaya
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Michael P Hughes
- Department of Cell and Molecular Biology, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - David R Boyer
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Qin Cao
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Romany Abskharon
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Duilio Cascio
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Einav Tayeb-Fligelman
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - David S Eisenberg
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA.
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3
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Kofler M, Kapus A. Nuclear Import and Export of YAP and TAZ. Cancers (Basel) 2023; 15:4956. [PMID: 37894323 PMCID: PMC10605228 DOI: 10.3390/cancers15204956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/05/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Yes-associated Protein (YAP) and its paralog Transcriptional Coactivator with PDZ-binding Motif (TAZ) are major regulators of gene transcription/expression, primarily controlled by the Hippo pathway and the cytoskeleton. Integrating an array of chemical and mechanical signals, they impact growth, differentiation, and regeneration. Accordingly, they also play key roles in tumorigenesis and metastasis formation. Their activity is primarily regulated by their localization, that is, Hippo pathway- and/or cytoskeleton-controlled cytosolic or nuclear sequestration. While many details of such prevailing retention models have been elucidated, much less is known about their actual nuclear traffic: import and export. Although their size is not far from the cutoff for passive diffusion through the nuclear pore complex (NPC), and they do not contain any classic nuclear localization (NLS) or nuclear export signal (NES), evidence has been accumulating that their shuttling involves mediated and thus regulatable/targetable processes. The aim of this review is to summarize emerging information/concepts about their nucleocytoplasmic shuttling, encompassing the relevant structural requirements (NLS, NES), nuclear transport receptors (NTRs, karyophererins), and NPC components, along with the potential transport mechanisms and their regulation. While dissecting retention vs. transport is often challenging, the emerging picture suggests that YAP/TAZ shuttles across the NPC via multiple, non-exclusive, mediated mechanisms, constituting a novel and intriguing facet of YAP/TAZ biology.
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Affiliation(s)
- Michael Kofler
- Keenan Research Centre for Biomedical Science of the St. Michael’s Hospital, Toronto, ON M5B 1W8, Canada;
| | - András Kapus
- Keenan Research Centre for Biomedical Science of the St. Michael’s Hospital, Toronto, ON M5B 1W8, Canada;
- Department of Surgery, University of Toronto, Toronto, ON M5T 1P5, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5B 1T8, Canada
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4
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Gonzalez A, Kim HJ, Freibaum BD, Fung HYJ, Brautigam CA, Taylor JP, Chook YM. A new Karyopherin-β2 binding PY-NLS epitope of HNRNPH2 linked to neurodevelopmental disorders. Structure 2023; 31:924-934.e4. [PMID: 37279758 PMCID: PMC10524338 DOI: 10.1016/j.str.2023.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/27/2023] [Accepted: 05/11/2023] [Indexed: 06/08/2023]
Abstract
The HNRNPH2 proline-tyrosine nuclear localization signal (PY-NLS) is mutated in HNRNPH2-related X-linked neurodevelopmental disorder, causing the normally nuclear HNRNPH2 to accumulate in the cytoplasm. We solved the cryoelectron microscopy (cryo-EM) structure of Karyopherin-β2/Transportin-1 bound to the HNRNPH2 PY-NLS to understand importin-NLS recognition and disruption in disease. HNRNPH2 206RPGPY210 is a typical R-X2-4-P-Y motif comprising PY-NLS epitopes 2 and 3, followed by an additional Karyopherin-β2-binding epitope, we term epitope 4, at residues 211DRP213; no density is present for PY-NLS epitope 1. Disease variant mutations at epitopes 2-4 impair Karyopherin-β2 binding and cause aberrant cytoplasmic accumulation in cells, emphasizing the role of nuclear import defect in disease. Sequence/structure analysis suggests that strong PY-NLS epitopes 4 are rare and thus far limited to close paralogs of HNRNPH2, HNRNPH1, and HNRNPF. Epitope 4-binidng hotspot Karyopherin-β2 W373 corresponds to close paralog Karyopherin-β2b/Transportin-2 W370, a pathological variant site in neurodevelopmental abnormalities, suggesting that Karyopherin-β2b/Transportin-2-HNRNPH2/H1/F interactions may be compromised in the abnormalities.
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Affiliation(s)
- Abner Gonzalez
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hong Joo Kim
- Department of Cell and Molecular Biology, St. Jude Children's Hospital, Memphis, TN, USA
| | - Brian D Freibaum
- Department of Cell and Molecular Biology, St. Jude Children's Hospital, Memphis, TN, USA
| | - Ho Yee Joyce Fung
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chad A Brautigam
- Departments of Biophysics and Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - J Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children's Hospital, Memphis, TN, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Yuh Min Chook
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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5
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Fare CM, Rhine K, Lam A, Myong S, Shorter J. A minimal construct of nuclear-import receptor Karyopherin-β2 defines the regions critical for chaperone and disaggregation activity. J Biol Chem 2023; 299:102806. [PMID: 36529289 PMCID: PMC9860449 DOI: 10.1016/j.jbc.2022.102806] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
Karyopherin-β2 (Kapβ2) is a nuclear-import receptor that recognizes proline-tyrosine nuclear localization signals of diverse cytoplasmic cargo for transport to the nucleus. Kapβ2 cargo includes several disease-linked RNA-binding proteins with prion-like domains, such as FUS, TAF15, EWSR1, hnRNPA1, and hnRNPA2. These RNA-binding proteins with prion-like domains are linked via pathology and genetics to debilitating degenerative disorders, including amyotrophic lateral sclerosis, frontotemporal dementia, and multisystem proteinopathy. Remarkably, Kapβ2 prevents and reverses aberrant phase transitions of these cargoes, which is cytoprotective. However, the molecular determinants of Kapβ2 that enable these activities remain poorly understood, particularly from the standpoint of nuclear-import receptor architecture. Kapβ2 is a super-helical protein comprised of 20 HEAT repeats. Here, we design truncated variants of Kapβ2 and assess their ability to antagonize FUS aggregation and toxicity in yeast and FUS condensation at the pure protein level and in human cells. We find that HEAT repeats 8 to 20 of Kapβ2 recapitulate all salient features of Kapβ2 activity. By contrast, Kapβ2 truncations lacking even a single cargo-binding HEAT repeat display reduced activity. Thus, we define a minimal Kapβ2 construct for delivery in adeno-associated viruses as a potential therapeutic for amyotrophic lateral sclerosis/frontotemporal dementia, multisystem proteinopathy, and related disorders.
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Affiliation(s)
- Charlotte M Fare
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kevin Rhine
- Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, Baltimore, Maryland, USA; Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Andrew Lam
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sua Myong
- Program in Cell, Molecular, Developmental Biology, and Biophysics, Johns Hopkins University, Baltimore, Maryland, USA; Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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6
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Gonzalez A, Kim HJ, Freibaum BD, Joyce Fung HY, Brautigam CA, Taylor JP, Chook YM. A new Karyopherin-β2 binding PY-NLS epitope of HNRNPH2 is linked to neurodevelopmental disorders. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524964. [PMID: 36711837 PMCID: PMC9882364 DOI: 10.1101/2023.01.20.524964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The normally nuclear HNRNPH2 is mutated in HNRNPH2 -related X-linked neurodevelopmental disorder causing the protein to accumulate in the cytoplasm. Interactions of HNRNPH2 with its importin Karyopherin-β2 (Transportin-1) had not been studied. We present a structure that shows Karyopherin-β2 binding HNRNPH2 residues 204-215, a proline-tyrosine nuclear localization signal or PY-NLS that contains a typical R-X 2-4 -P-Y motif, 206 RPGPY 210 , followed a new Karyopherin-β2 binding epitope at 211 DRP 213 that make many interactions with Karyopherin-β2 W373. Mutations at each of these sites decrease Karyopherin-β2 binding affinities by 70-100 fold, explaining aberrant accumulation in cells and emphasizing the role of nuclear import defects in the disease. Sequence/structure analysis suggests that the new epitope C-terminal of the PY-motif, which binds Karyopherin-β2 W373, is rare and thus far limited to close paralogs HNRNPH2, HNRNPH1 and HNRNPF. Karyopherin-β2 W373, a HNRNPH2-binding hotspot, corresponds to W370 of close paralog Transportin-2, a site of pathological variants in patients with neurodevelopmental abnormalities, suggesting that Transportin-2-HNRNPH2/H1/F interactions may be compromised in the abnormalities. Summary HNRNPH2 variants in HNRNPH2 -related X-linked neurodevelopmental disorder aberrantly accumulate in the cytoplasm. A structure of Karyopherin-β2•HNRNPH2 explains nuclear import defects of the variants, reveals a new NLS epitope that suggests mechanistic changes in pathological variants of Karyopherin-β2 paralog Transportin-2.
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7
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Pörschke M, Rodríguez-González I, Parfentev I, Urlaub H, Kehlenbach RH. Transportin 1 is a major nuclear import receptor of the nitric oxide synthase interacting protein. J Biol Chem 2023; 299:102932. [PMID: 36690276 PMCID: PMC9974451 DOI: 10.1016/j.jbc.2023.102932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 01/12/2023] [Accepted: 01/14/2023] [Indexed: 01/22/2023] Open
Abstract
The nitric oxide synthase interacting protein (NOSIP), an E3-ubiquitin ligase, is involved in various processes like neuronal development, craniofacial development, granulopoiesis, mitogenic signaling, apoptosis, and cell proliferation. The best-characterized function of NOSIP is the regulation of endothelial nitric oxide synthase activity by translocating the membrane-bound enzyme to the cytoskeleton, specifically in the G2 phase of the cell cycle. For this, NOSIP itself has to be translocated from its prominent localization, the nucleus, to the cytoplasm. Nuclear import of NOSIP was suggested to be mediated by the canonical transport receptors importin α/β. Recently, we found NOSIP in a proteomic screen as a potential importin 13 cargo. Here, we describe the nuclear shuttling characteristics of NOSIP in living cells and in vitro and show that it does not interact directly with importin α. Instead, it formed stable complexes with several importins (-β, -7, -β/7, -13, and transportin 1) and was also imported into the nucleus in digitonin-permeabilized cells by these factors. In living HeLa cells, transportin 1 seems to be the major nuclear import receptor for NOSIP. A detailed analysis of the NOSIP-transportin 1 interaction revealed a high affinity and an unusual binding mode, involving the N-terminal half of transportin 1. In contrast to nuclear import, nuclear export of NOSIP seems to occur mostly by passive diffusion. Thus, our results uncover additional layers in the larger process of endothelial nitric oxide synthase regulation.
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Affiliation(s)
- Marius Pörschke
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Inés Rodríguez-González
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Iwan Parfentev
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany,Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Ralph H. Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Göttingen, Germany,For correspondence: Ralph H. Kehlenbach
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8
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Hwang WY, Kostiuk V, González DP, Lusk CP, Khokha MK. Kap-β2/Transportin mediates β-catenin nuclear transport in Wnt signaling. eLife 2022; 11:e70495. [PMID: 36300792 PMCID: PMC9665845 DOI: 10.7554/elife.70495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/26/2022] [Indexed: 11/13/2022] Open
Abstract
Wnt signaling is essential for many aspects of embryonic development including the formation of the primary embryonic axis. In addition, excessive Wnt signaling drives multiple diseases including cancer, highlighting its importance for disease pathogenesis. β-catenin is a key effector in this pathway that translocates into the nucleus and activates Wnt responsive genes. However, due to our lack of understanding of β-catenin nuclear transport, therapeutic modulation of Wnt signaling has been challenging. Here, we took an unconventional approach to address this long-standing question by exploiting a heterologous model system, the budding yeast Saccharomyces cerevisiae, which contains a conserved nuclear transport machinery. In contrast to prior work, we demonstrate that β-catenin accumulates in the nucleus in a Ran-dependent manner, suggesting the use of a nuclear transport receptor (NTR). Indeed, a systematic and conditional inhibition of NTRs revealed that only Kap104, the ortholog of Kap-β2/Transportin-1 (TNPO1), was required for β-catenin nuclear import. We further demonstrate direct binding between TNPO1 and β-catenin that is mediated by a conserved PY-NLS. Finally, using Xenopus secondary axis and TCF/LEF (T Cell factor/lymphoid enhancer factor family) reporter assays, we demonstrate that our results in yeast can be directly translated to vertebrates. By elucidating the nuclear localization signal in β-catenin and its cognate NTR, our study suggests new therapeutic targets for a host of human diseases caused by excessive Wnt signaling. Indeed, we demonstrate that a small chimeric peptide designed to target TNPO1 can reduce Wnt signaling as a first step toward therapeutics.
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Affiliation(s)
- Woong Y Hwang
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale School of MedicineNew HavenUnited States
| | - Valentyna Kostiuk
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale School of MedicineNew HavenUnited States
| | - Delfina P González
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale School of MedicineNew HavenUnited States
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of MedicineNew HavenUnited States
| | - Mustafa K Khokha
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale School of MedicineNew HavenUnited States
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Structure of IMPORTIN-4 bound to the H3-H4-ASF1 histone-histone chaperone complex. Proc Natl Acad Sci U S A 2022; 119:e2207177119. [PMID: 36103578 PMCID: PMC9499513 DOI: 10.1073/pnas.2207177119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
IMPORTIN-4, the primary nuclear import receptor of core histones H3 and H4, binds the H3-H4 dimer and histone chaperone ASF1 prior to nuclear import. However, how H3-H3-ASF1 is recognized for transport cannot be explained by available crystal structures of IMPORTIN-4-histone tail peptide complexes. Our 3.5-Å IMPORTIN-4-H3-H4-ASF1 cryoelectron microscopy structure reveals the full nuclear import complex and shows a binding mode different from suggested by previous structures. The N-terminal half of IMPORTIN-4 clamps the globular H3-H4 domain and H3 αN helix, while its C-terminal half binds the H3 N-terminal tail weakly; tail contribution to binding energy is negligible. ASF1 binds H3-H4 without contacting IMPORTIN-4. Together, ASF1 and IMPORTIN-4 shield nucleosomal H3-H4 surfaces to chaperone and import it into the nucleus where RanGTP binds IMPORTIN-4, causing large conformational changes to release H3-H4-ASF1. This work explains how full-length H3-H4 binds IMPORTIN-4 in the cytoplasm and how it is released in the nucleus.
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10
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Karasev MM, Baloban M, Verkhusha VV, Shcherbakova DM. Nuclear Localization Signals for Optimization of Genetically Encoded Tools in Neurons. Front Cell Dev Biol 2022; 10:931237. [PMID: 35927988 PMCID: PMC9344056 DOI: 10.3389/fcell.2022.931237] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/24/2022] [Indexed: 12/15/2022] Open
Abstract
Nuclear transport in neurons differs from that in non-neuronal cells. Here we developed a non-opsin optogenetic tool (OT) for the nuclear export of a protein of interest induced by near-infrared (NIR) light. In darkness, nuclear import reverses the OT action. We used this tool for comparative analysis of nuclear transport dynamics mediated by nuclear localization signals (NLSs) with different importin specificities. We found that widely used KPNA2-binding NLSs, such as Myc and SV40, are suboptimal in neurons. We identified uncommon NLSs mediating fast nuclear import and demonstrated that the performance of the OT for nuclear export can be adjusted by varying NLSs. Using these NLSs, we optimized the NIR OT for light-controlled gene expression for lower background and higher contrast in neurons. The selected NLSs binding importins abundant in neurons could improve performance of genetically encoded tools in these cells, including OTs and gene-editing tools.
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Affiliation(s)
- Maksim M. Karasev
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Mikhail Baloban
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Vladislav V. Verkhusha
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Daria M. Shcherbakova
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, United States
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11
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Zou J, Yu L, Zhu Y, Yang S, Zhao J, Zhao Y, Jiang M, Xie S, Liu H, Zhao C, Zhou H. Transportin-3 Facilitates Uncoating of Influenza A Virus. Int J Mol Sci 2022; 23:ijms23084128. [PMID: 35456945 PMCID: PMC9027869 DOI: 10.3390/ijms23084128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 03/25/2022] [Accepted: 04/02/2022] [Indexed: 02/01/2023] Open
Abstract
Influenza A viruses (IAVs) are a major global health threat and in the future, may cause the next pandemic. Although studies have partly uncovered the molecular mechanism of IAV–host interaction, it requires further research. In this study, we explored the roles of transportin-3 (TNPO3) in IAV infection. We found that TNPO3-deficient cells inhibited infection with four different IAV strains, whereas restoration of TNPO3 expression in knockout (KO) cells restored IAV infection. TNPO3 overexpression in wild-type (WT) cells promoted IAV infection, suggesting that TNPO3 is involved in the IAV replication. Furthermore, we found that TNPO3 depletion restrained the uncoating in the IAV life cycle, thereby inhibiting the process of viral ribonucleoprotein (vRNP) entry into the nucleus. However, KO of TNPO3 did not affect the virus attachment, endocytosis, or endosomal acidification processes. Subsequently, we found that TNPO3 can colocalize and interact with viral proteins M1 and M2. Taken together, the depletion of TNPO3 inhibits IAV uncoating, thereby inhibiting IAV replication. Our study provides new insights and potential therapeutic targets for unraveling the mechanism of IAV replication and treating influenza disease.
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Affiliation(s)
- Jiahui Zou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (J.Z.); (L.Y.); (Y.Z.); (S.Y.); (J.Z.); (Y.Z.); (M.J.)
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Luyao Yu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (J.Z.); (L.Y.); (Y.Z.); (S.Y.); (J.Z.); (Y.Z.); (M.J.)
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Yinxing Zhu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (J.Z.); (L.Y.); (Y.Z.); (S.Y.); (J.Z.); (Y.Z.); (M.J.)
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Shuaike Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (J.Z.); (L.Y.); (Y.Z.); (S.Y.); (J.Z.); (Y.Z.); (M.J.)
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Jiachang Zhao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (J.Z.); (L.Y.); (Y.Z.); (S.Y.); (J.Z.); (Y.Z.); (M.J.)
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Yaxin Zhao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (J.Z.); (L.Y.); (Y.Z.); (S.Y.); (J.Z.); (Y.Z.); (M.J.)
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Meijun Jiang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (J.Z.); (L.Y.); (Y.Z.); (S.Y.); (J.Z.); (Y.Z.); (M.J.)
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Shengsong Xie
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China; (S.X.); (H.L.); (C.Z.)
| | - Hailong Liu
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China; (S.X.); (H.L.); (C.Z.)
| | - Changzhi Zhao
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education & Key Lab of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China; (S.X.); (H.L.); (C.Z.)
| | - Hongbo Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (J.Z.); (L.Y.); (Y.Z.); (S.Y.); (J.Z.); (Y.Z.); (M.J.)
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
- Correspondence:
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Importin alpha 1 is required for the nucleus entry of Fowl Adenovirus serotype 4 Fiber-1 protein. Vet Microbiol 2022; 266:109351. [PMID: 35121306 DOI: 10.1016/j.vetmic.2022.109351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/23/2022]
Abstract
Fiber-1 protein (F1) is the structural protein of Fowl Adenovirus serotype 4 (FAdV-4), which could recondite the receptors of host cytomembrane. In this study, we firstly determined that F1 protein located in nucleus of LMH cells after infection with FAdV-4. We additionally revealed that F1 protein had a classic NLS, and the NLS was required for F1 nucleus entry, which was intently associated to the 26th Pro in NLS. The time rule result indicated that some F1 proteins firstly positioned in the nucleus 6 h posttranfection, and it entirely located in the nucleus 12 h posttranfection, then it ordinarily placed in cytoplasm 18 h posttranfection by means of microscopic fluorescence observation and Western Blotting. Then after transfection with pCI-neo-flag-F1 or infection with FAdV-4, the importin alpha 1 was once investigated whether or not it was required for F1 protein nucleus entry through immunofluorescence and/or Co-IP, results demonstrated that the F1 protein and importin alpha 1 co-located in the nucleus 6 h and 12 h posttranfection. The tiers of F1 protein vicinity in nucleus have been additionally investigated after knockdown expression or overexpression of importin alpha 1, and the results further revealed that importin alpha 1 used to be required for F1 protein nucleus entry. Finally, the function of F1 protein nucleus entry was investigated by qPCR, RT-PCR and Western Blotting, and the results revealed that F1 protein nucleus location was conducive to the proliferation of FAdV-4. In summary, we firstly reveal that the F1 protein of FAdV-4 locates in nucleus infected with FAdV-4, and confirm that importin alpha 1 binds to the NLS of F1 protein to nucleus localization, which promotes the proliferation of FAdV-4.
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Wing CE, Fung HYJ, Chook YM. Karyopherin-mediated nucleocytoplasmic transport. Nat Rev Mol Cell Biol 2022; 23:307-328. [PMID: 35058649 PMCID: PMC10101760 DOI: 10.1038/s41580-021-00446-7] [Citation(s) in RCA: 107] [Impact Index Per Article: 53.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2021] [Indexed: 12/25/2022]
Abstract
Efficient and regulated nucleocytoplasmic trafficking of macromolecules to the correct subcellular compartment is critical for proper functions of the eukaryotic cell. The majority of the macromolecular traffic across the nuclear pores is mediated by the Karyopherin-β (or Kap) family of nuclear transport receptors. Work over more than two decades has shed considerable light on how the different Kap family members bring their respective cargoes into the nucleus or the cytoplasm in efficient and highly regulated manners. In this Review, we overview the main features and established functions of Kap family members, describe how Kaps recognize their cargoes and discuss the different ways in which these Kap-cargo interactions can be regulated, highlighting new findings and open questions. We also describe current knowledge of the import and export of the components of three large gene expression machines - the core replisome, RNA polymerase II and the ribosome - pointing out the questions that persist about how such large macromolecular complexes are trafficked to serve their function in a designated subcellular location.
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Ramic M, Andrade NS, Rybin MJ, Esanov R, Wahlestedt C, Benatar M, Zeier Z. Epigenetic Small Molecules Rescue Nucleocytoplasmic Transport and DNA Damage Phenotypes in C9ORF72 ALS/FTD. Brain Sci 2021; 11:brainsci11111543. [PMID: 34827542 PMCID: PMC8616043 DOI: 10.3390/brainsci11111543] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/11/2021] [Accepted: 11/18/2021] [Indexed: 01/04/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease with available treatments only marginally slowing progression or improving survival. A hexanucleotide repeat expansion mutation in the C9ORF72 gene is the most commonly known genetic cause of both sporadic and familial cases of ALS and frontotemporal dementia (FTD). The C9ORF72 expansion mutation produces five dipeptide repeat proteins (DPRs), and while the mechanistic determinants of DPR-mediated neurotoxicity remain incompletely understood, evidence suggests that disruption of nucleocytoplasmic transport and increased DNA damage contributes to pathology. Therefore, characterizing these disturbances and determining the relative contribution of different DPRs is needed to facilitate the development of novel therapeutics for C9ALS/FTD. To this end, we generated a series of nucleocytoplasmic transport “biosensors”, composed of the green fluorescent protein (GFP), fused to different classes of nuclear localization signals (NLSs) and nuclear export signals (NESs). Using these biosensors in conjunction with automated microscopy, we investigated the role of the three most neurotoxic DPRs (PR, GR, and GA) on seven nuclear import and two export pathways. In addition to other DPRs, we found that PR had pronounced inhibitory effects on the classical nuclear export pathway and several nuclear import pathways. To identify compounds capable of counteracting the effects of PR on nucleocytoplasmic transport, we developed a nucleocytoplasmic transport assay and screened several commercially available compound libraries, totaling 2714 compounds. In addition to restoring nucleocytoplasmic transport efficiencies, hits from the screen also counteract the cytotoxic effects of PR. Selected hits were subsequently tested for their ability to rescue another C9ALS/FTD phenotype—persistent DNA double strand breakage. Overall, we found that DPRs disrupt multiple nucleocytoplasmic transport pathways and we identified small molecules that counteract these effects—resulting in increased viability of PR-expressing cells and decreased DNA damage markers in patient-derived motor neurons. Several HDAC inhibitors were validated as hits, supporting previous studies that show that HDAC inhibitors confer therapeutic effects in neurodegenerative models.
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Affiliation(s)
- Melina Ramic
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Nadja S. Andrade
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Matthew J. Rybin
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Rustam Esanov
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Claes Wahlestedt
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Michael Benatar
- Department of Neurology, University of Miami Miller School of Medicine, 1120 NW 14th St., Miami, FL 33136, USA;
| | - Zane Zeier
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
- Correspondence: ; Tel.: +1-305-243-1367
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15
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Bonet LFS, Loureiro JP, Pereira GRC, Da Silva ANR, De Mesquita JF. Molecular dynamics and protein frustration analysis of human fused in Sarcoma protein variants in Amyotrophic Lateral Sclerosis type 6: An In Silico approach. PLoS One 2021; 16:e0258061. [PMID: 34587215 PMCID: PMC8480726 DOI: 10.1371/journal.pone.0258061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/16/2021] [Indexed: 11/18/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the most frequent adult-onset motor neuron disorder. The disease is characterized by degeneration of upper and lower motor neurons, leading to death usually within five years after the onset of symptoms. While most cases are sporadic, 5%-10% of cases can be associated with familial inheritance, including ALS type 6, which is associated with mutations in the Fused in Sarcoma (FUS) gene. This work aimed to evaluate how the most frequent ALS-related mutations in FUS, R521C, R521H, and P525L affect the protein structure and function. We used prediction algorithms to analyze the effects of the non-synonymous single nucleotide polymorphisms and performed evolutionary conservation analysis, protein frustration analysis, and molecular dynamics simulations. Most of the prediction algorithms classified the three mutations as deleterious. All three mutations were predicted to reduce protein stability, especially the mutation R521C, which was also predicted to increase chaperone binding tendency. The protein frustration analysis showed an increase in frustration in the interactions involving the mutated residue 521C. Evolutionary conservation analysis showed that residues 521 and 525 of human FUS are highly conserved sites. The molecular dynamics results indicate that protein stability could be compromised in all three mutations. They also affected the exposed surface area and protein compactness. The analyzed mutations also displayed high flexibility in most residues in all variants, most notably in the interaction site with the nuclear import protein of FUS.
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Affiliation(s)
- L. F. S. Bonet
- Department of Genetics and Molecular Biology, Laboratory of Bioinformatics and Computational Biology, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - J. P. Loureiro
- Department of Genetics and Molecular Biology, Laboratory of Bioinformatics and Computational Biology, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - G. R. C. Pereira
- Department of Genetics and Molecular Biology, Laboratory of Bioinformatics and Computational Biology, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - A. N. R. Da Silva
- Department of Genetics and Molecular Biology, Laboratory of Bioinformatics and Computational Biology, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - J. F. De Mesquita
- Department of Genetics and Molecular Biology, Laboratory of Bioinformatics and Computational Biology, Federal University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
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Nuclear import of histones. Biochem Soc Trans 2021; 48:2753-2767. [PMID: 33300986 PMCID: PMC7752055 DOI: 10.1042/bst20200572] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/30/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022]
Abstract
The transport of histones from the cytoplasm to the nucleus of the cell, through the nuclear membrane, is a cellular process that regulates the supply of new histones in the nucleus and is key for DNA replication and transcription. Nuclear import of histones is mediated by proteins of the karyopherin family of nuclear transport receptors. Karyopherins recognize their cargos through linear motifs known as nuclear localization/export sequences or through folded domains in the cargos. Karyopherins interact with nucleoporins, proteins that form the nuclear pore complex, to promote the translocation of their cargos into the nucleus. When binding to histones, karyopherins not only function as nuclear import receptors but also as chaperones, protecting histones from non-specific interactions in the cytoplasm, in the nuclear pore and possibly in the nucleus. Studies have also suggested that karyopherins might participate in histones deposition into nucleosomes. In this review we describe structural and biochemical studies from the last two decades on how karyopherins recognize and transport the core histone proteins H3, H4, H2A and H2B and the linker histone H1 from the cytoplasm to the nucleus, which karyopherin is the major nuclear import receptor for each of these histones, the oligomeric state of histones during nuclear import and the roles of post-translational modifications, histone-chaperones and RanGTP in regulating these nuclear import pathways.
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17
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Kimura M, Imai K, Morinaka Y, Hosono-Sakuma Y, Horton P, Imamoto N. Distinct mutations in importin-β family nucleocytoplasmic transport receptors transportin-SR and importin-13 affect specific cargo binding. Sci Rep 2021; 11:15649. [PMID: 34341383 PMCID: PMC8329185 DOI: 10.1038/s41598-021-94948-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 07/20/2021] [Indexed: 01/25/2023] Open
Abstract
Importin-(Imp)β family nucleocytoplasmic transport receptors (NTRs) are supposed to bind to their cargoes through interaction between a confined interface on an NTR and a nuclear localization or export signal (NLS/NES) on a cargo. Although consensus NLS/NES sequence motifs have been defined for cargoes of some NTRs, many experimentally identified cargoes of those NTRs lack those motifs, and consensus NLSs/NESs have been reported for only a few NTRs. Crystal structures of NTR-cargo complexes have exemplified 3D structure-dependent binding of cargoes lacking a consensus NLS/NES to different sites on an NTR. Since only a limited number of NTR-cargo interactions have been studied, whether most cargoes lacking a consensus NLS/NES bind to the same confined interface or to various sites on an NTR is still unclear. Addressing this issue, we generated four mutants of transportin-(Trn)SR, of which many cargoes lack a consensus NLS, and eight mutants of Imp13, where no consensus NLS has been defined, and we analyzed their binding to as many as 40 cargo candidates that we previously identified by a nuclear import reaction-based method. The cargoes bind differently to the NTR mutants, suggesting that positions on an NTR contribute differently to the binding of respective cargoes.
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Affiliation(s)
- Makoto Kimura
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan.
| | - Kenichiro Imai
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan.
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan.
| | - Yuriko Morinaka
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
| | - Yoshiko Hosono-Sakuma
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan
| | - Paul Horton
- Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan City, Taiwan
| | - Naoko Imamoto
- Cellular Dynamics Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan.
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Mboukou A, Rajendra V, Kleinova R, Tisné C, Jantsch MF, Barraud P. Transportin-1: A Nuclear Import Receptor with Moonlighting Functions. Front Mol Biosci 2021; 8:638149. [PMID: 33681296 PMCID: PMC7930572 DOI: 10.3389/fmolb.2021.638149] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 01/13/2021] [Indexed: 12/11/2022] Open
Abstract
Transportin-1 (Trn1), also known as karyopherin-β2 (Kapβ2), is probably the best-characterized nuclear import receptor of the karyopherin-β family after Importin-β, but certain aspects of its functions in cells are still puzzling or are just recently emerging. Since the initial identification of Trn1 as the nuclear import receptor of hnRNP A1 ∼25 years ago, several molecular and structural studies have unveiled and refined our understanding of Trn1-mediated nuclear import. In particular, the understanding at a molecular level of the NLS recognition by Trn1 made a decisive step forward with the identification of a new class of NLSs called PY-NLSs, which constitute the best-characterized substrates of Trn1. Besides PY-NLSs, many Trn1 cargoes harbour NLSs that do not resemble the archetypical PY-NLS, which complicates the global understanding of cargo recognition by Trn1. Although PY-NLS recognition is well established and supported by several structures, the recognition of non-PY-NLSs by Trn1 is far less understood, but recent reports have started to shed light on the recognition of this type of NLSs. Aside from its principal and long-established activity as a nuclear import receptor, Trn1 was shown more recently to moonlight outside nuclear import. Trn1 has for instance been caught in participating in virus uncoating, ciliary transport and in modulating the phase separation properties of aggregation-prone proteins. Here, we focus on the structural and functional aspects of Trn1-mediated nuclear import, as well as on the moonlighting activities of Trn1.
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Affiliation(s)
- Allegra Mboukou
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université de Paris, Paris, France
| | - Vinod Rajendra
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Renata Kleinova
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Carine Tisné
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université de Paris, Paris, France
| | - Michael F. Jantsch
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Pierre Barraud
- Expression Génétique Microbienne, Institut de Biologie Physico-Chimique (IBPC), UMR 8261, CNRS, Université de Paris, Paris, France
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Pokorná P, Krepl M, Šponer J. Residues flanking the ARK me3T/S motif allow binding of diverse targets to the HP1 chromodomain: Insights from molecular dynamics simulations. Biochim Biophys Acta Gen Subj 2020; 1865:129771. [PMID: 33153976 DOI: 10.1016/j.bbagen.2020.129771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/15/2020] [Accepted: 10/20/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND The chromodomain (CD) of HP1 proteins is an established H3K9me3 reader that also binds H1, EHMT2 and H3K23 lysine-methylated targets. Structural experiments have provided atomistic pictures of its recognition of the conserved ARKme3S/T motif, but structural dynamics' contribution to the recognition may have been masked by ensemble averaging. METHODS We acquired ~350 μs of explicit solvent molecular dynamics (MD) simulations of the CD domain interacting with several peptides using the latest AMBER force fields. RESULTS The simulations reproduced the experimentally observed static binding patterns well but also revealed visible structural dynamics at the interfaces. While the buried K0me3 and A-2 target residues are tightly bound, several flanking sidechains sample diverse sites on the CD surface. Different amino acid positions of the targets can substitute for each other by forming mutually replaceable interactions with CD, thereby explaining the lack of strict requirement for cationic H3 target residues at the -3 position. The Q-4 residue of H3 targets further stabilizes the binding. The recognition pattern of the H3K23 ATKme3A motif, for which no structure is available, is predicted. CONCLUSIONS The CD reads a longer target segment than previously thought, ranging from positions -7 to +3. The CD anionic clamp can be neutralized not only by the -3 and -1 residues, but also by -7, -6, -5 and +3 residues. GENERAL SIGNIFICANCE Structural dynamics, not immediately apparent from the structural data, contribute to molecular recognition between the HP1 CD domain and its targets. Mutual replaceability of target residues increases target sequence flexibility.
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Affiliation(s)
- Pavlína Pokorná
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.
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20
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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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Abstract
Influenza A virus (IAV) is an enveloped virus of the Orthomyxoviridae with a negative-sense single-stranded RNA genome. During virus cell entry, viral and cellular cues are delivered in a stepwise manner within two distinct cellular compartments-the endosomes and the cytosol. Endosome maturation primes the viral core for uncoating by cytosolic host proteins and host-mediated virus disaggregation is essential for genome import and replication in the nucleus. Recent evidence shows that two well-known cellular proteins-histone deacetylase 6 (HDAC6) and karyopherin-β2 (kapβ2)-uncoat influenza virus. HDAC6 is 1 of 11 HDACs and an X-linked, cytosolic lysine deacetylase. Under normal cellular conditions HDAC6 is the tubulin deacetylase. Under proteasomal stress HDAC6 binds unanchored ubiquitin, dynein and myosin II to sequester misfolded protein aggregates for autophagy. Kapβ2 is a member of the importin β family that transports RNA-binding proteins into the nucleus by binding to disordered nuclear localization signals (NLSs) known as PY-NLS. Kapβ2 is emerging as a universal uncoating factor for IAV and human immunodeficiency virus type 1 (HIV-1). Kapβ2 can also reverse liquid-liquid phase separation (LLPS) of RNA-binding proteins by promoting their disaggregation. Thus, it is becoming evident that key players in the management of cellular condensates and membraneless organelles are potent virus uncoating factors. This emerging concept reveals implications in viral pathogenesis, as well as, the promise for cell-targeted therapeutic strategies to block universal virus uncoating pathways hijacked by enveloped RNA viruses.
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Affiliation(s)
- Yohei Yamauchi
- School of Cellular & Molecular Medicine, University of Bristol, Bristol, United Kingdom.
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Transportin-1 binds to the HIV-1 capsid via a nuclear localization signal and triggers uncoating. Nat Microbiol 2019; 4:1840-1850. [PMID: 31611641 DOI: 10.1038/s41564-019-0575-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 08/30/2019] [Indexed: 01/05/2023]
Abstract
The initial steps of HIV replication in host cells prime the virus for passage through the nuclear pore and drive the establishment of a productive and irreparable infection1,2. The timely release of the viral genome from the capsid-referred to as uncoating-is emerging as a critical parameter for nuclear import, but the triggers and mechanisms that orchestrate these steps are unknown. Here, we identify β-karyopherin Transportin-1 (TRN-1) as a cellular co-factor of HIV-1 infection, which binds to incoming capsids, triggers their uncoating and promotes viral nuclear import. Depletion of TRN-1, which we characterized by mass spectrometry, significantly reduced the early steps of HIV-1 infection in target cells, including primary CD4+ T cells. TRN-1 bound directly to capsid nanotubes and induced dramatic structural damage, indicating that TRN-1 is necessary and sufficient for uncoating in vitro. Glycine 89 on the capsid protein, which is positioned within a nuclear localization signal in the cyclophilin A-binding loop, is critical for engaging the hydrophobic pocket of TRN-1 at position W730. In addition, TRN-1 promotes the efficient nuclear import of both viral DNA and capsid protein. Our study suggests that TRN-1 mediates the timely release of the HIV-1 genome from the capsid protein shell and efficient viral nuclear import.
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Tessier TM, Dodge MJ, Prusinkiewicz MA, Mymryk JS. Viral Appropriation: Laying Claim to Host Nuclear Transport Machinery. Cells 2019; 8:E559. [PMID: 31181773 PMCID: PMC6627039 DOI: 10.3390/cells8060559] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 06/05/2019] [Accepted: 06/06/2019] [Indexed: 12/13/2022] Open
Abstract
Protein nuclear transport is an integral process to many cellular pathways and often plays a critical role during viral infection. To overcome the barrier presented by the nuclear membrane and gain access to the nucleus, virally encoded proteins have evolved ways to appropriate components of the nuclear transport machinery. By binding karyopherins, or the nuclear pore complex, viral proteins influence their own transport as well as the transport of key cellular regulatory proteins. This review covers how viral proteins can interact with different components of the nuclear import machinery and how this influences viral replicative cycles. We also highlight the effects that viral perturbation of nuclear transport has on the infected host and how we can exploit viruses as tools to study novel mechanisms of protein nuclear import. Finally, we discuss the possibility that drugs targeting these transport pathways could be repurposed for treating viral infections.
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Affiliation(s)
- Tanner M Tessier
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON N6A 3K7, Canada.
| | - Mackenzie J Dodge
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON N6A 3K7, Canada.
| | - Martin A Prusinkiewicz
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON N6A 3K7, Canada.
| | - Joe S Mymryk
- Department of Microbiology and Immunology, The University of Western Ontario, London, ON N6A 3K7, Canada.
- 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.
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24
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Yoshizawa T, Ali R, Jiou J, Fung HYJ, Burke KA, Kim SJ, Lin Y, Peeples WB, Saltzberg D, Soniat M, Baumhardt JM, Oldenbourg R, Sali A, Fawzi NL, Rosen MK, Chook YM. Nuclear Import Receptor Inhibits Phase Separation of FUS through Binding to Multiple Sites. Cell 2019; 173:693-705.e22. [PMID: 29677513 DOI: 10.1016/j.cell.2018.03.003] [Citation(s) in RCA: 216] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 11/29/2017] [Accepted: 02/28/2018] [Indexed: 01/04/2023]
Abstract
Liquid-liquid phase separation (LLPS) is believed to underlie formation of biomolecular condensates, cellular compartments that concentrate macromolecules without surrounding membranes. Physical mechanisms that control condensate formation/dissolution are poorly understood. The RNA-binding protein fused in sarcoma (FUS) undergoes LLPS in vitro and associates with condensates in cells. We show that the importin karyopherin-β2/transportin-1 inhibits LLPS of FUS. This activity depends on tight binding of karyopherin-β2 to the C-terminal proline-tyrosine nuclear localization signal (PY-NLS) of FUS. Nuclear magnetic resonance (NMR) analyses reveal weak interactions of karyopherin-β2 with sequence elements and structural domains distributed throughout the entirety of FUS. Biochemical analyses demonstrate that most of these same regions also contribute to LLPS of FUS. The data lead to a model where high-affinity binding of karyopherin-β2 to the FUS PY-NLS tethers the proteins together, allowing multiple, distributed weak intermolecular contacts to disrupt FUS self-association, blocking LLPS. Karyopherin-β2 may act analogously to control condensates in diverse cellular contexts.
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Affiliation(s)
- Takuya Yoshizawa
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rustam Ali
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jenny Jiou
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ho Yee Joyce Fung
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kathleen A Burke
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
| | - Seung Joong Kim
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Yuan Lin
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute (HHMI) Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - William B Peeples
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute (HHMI) Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Daniel Saltzberg
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Michael Soniat
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jordan M Baumhardt
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rudolf Oldenbourg
- Marine Biological Laboratories, 7 MBL Street, Woods Hole, MA 02543, USA
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, RI 02912, USA
| | - Michael K Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute (HHMI) Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543, USA.
| | - Yuh Min Chook
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Howard Hughes Medical Institute (HHMI) Summer Institute, Marine Biological Laboratory, Woods Hole, MA 02543, USA.
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25
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Influenza virus uses transportin 1 for vRNP debundling during cell entry. Nat Microbiol 2019; 4:578-586. [PMID: 30692667 DOI: 10.1038/s41564-018-0332-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/28/2018] [Indexed: 12/15/2022]
Abstract
Influenza A virus is a pathogen of great medical impact. To develop novel antiviral strategies, it is essential to understand the molecular aspects of virus-host cell interactions in detail. During entry, the viral ribonucleoproteins (vRNPs) that carry the RNA genome must be released from the incoming particle before they can enter the nucleus for replication. The uncoating process is facilitated by histone deacetylase 6 (ref.1). However, the precise mechanism of shell opening and vRNP debundling is unknown. Here, we show that transportin 1, a member of the importin-β family proteins, binds to a PY-NLS2 sequence motif close to the amino terminus of matrix protein (M1) exposed during acid priming of the viral core. It promotes the removal of M1 and induces disassembly of vRNP bundles. Next, the vRNPs interact with importin-α/β and enter the nucleus. Thus, influenza A virus uses dual importin-βs for distinct steps in host cell entry.
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26
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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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27
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Apta-Smith MJ, Hernandez-Fernaud JR, Bowman AJ. Evidence for the nuclear import of histones H3.1 and H4 as monomers. EMBO J 2018; 37:embj.201798714. [PMID: 30177573 PMCID: PMC6166134 DOI: 10.15252/embj.201798714] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 07/20/2018] [Accepted: 07/25/2018] [Indexed: 11/09/2022] Open
Abstract
Newly synthesised histones are thought to dimerise in the cytosol and undergo nuclear import in complex with histone chaperones. Here, we provide evidence that human H3.1 and H4 are imported into the nucleus as monomers. Using a tether-and-release system to study the import dynamics of newly synthesised histones, we find that cytosolic H3.1 and H4 can be maintained as stable monomeric units. Cytosolically tethered histones are bound to importin-alpha proteins (predominantly IPO4), but not to histone-specific chaperones NASP, ASF1a, RbAp46 (RBBP7) or HAT1, which reside in the nucleus in interphase cells. Release of monomeric histones from their cytosolic tether results in rapid nuclear translocation, IPO4 dissociation and incorporation into chromatin at sites of replication. Quantitative analysis of histones bound to individual chaperones reveals an excess of H3 specifically associated with sNASP, suggesting that NASP maintains a soluble, monomeric pool of H3 within the nucleus and may act as a nuclear receptor for newly imported histone. In summary, we propose that histones H3 and H4 are rapidly imported as monomeric units, forming heterodimers in the nucleus rather than the cytosol.
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Affiliation(s)
| | | | - Andrew James Bowman
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
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28
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Yoon J, Kim SJ, An S, Cho S, Leitner A, Jung T, Aebersold R, Hebert H, Cho US, Song JJ. Integrative Structural Investigation on the Architecture of Human Importin4_Histone H3/H4_Asf1a Complex and Its Histone H3 Tail Binding. J Mol Biol 2018; 430:822-841. [DOI: 10.1016/j.jmb.2018.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 11/15/2022]
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29
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An S, Yoon J, Kim H, Song JJ, Cho US. Structure-based nuclear import mechanism of histones H3 and H4 mediated by Kap123. eLife 2017; 6:30244. [PMID: 29035199 PMCID: PMC5677370 DOI: 10.7554/elife.30244] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/12/2017] [Indexed: 01/03/2023] Open
Abstract
Kap123, a major karyopherin protein of budding yeast, recognizes the nuclear localization signals (NLSs) of cytoplasmic histones H3 and H4 and translocates them into the nucleus during DNA replication. Mechanistic questions include H3- and H4-NLS redundancy toward Kap123 and the role of the conserved diacetylation of cytoplasmic H4 (K5ac and K12ac) in Kap123-mediated histone nuclear translocation. Here, we report crystal structures of full-length Kluyveromyces lactis Kap123 alone and in complex with H3- and H4-NLSs. Structures reveal the unique feature of Kap123 that possesses two discrete lysine-binding pockets for NLS recognition. Structural comparison illustrates that H3- and H4-NLSs share at least one of two lysine-binding pockets, suggesting that H3- and H4-NLSs are mutually exclusive. Additionally, acetylation of key lysine residues at NLS, particularly H4-NLS diacetylation, weakens the interaction with Kap123. These data support that cytoplasmic histone H4 diacetylation weakens the Kap123-H4-NLS interaction thereby facilitating histone Kap123-H3-dependent H3:H4/Asf1 complex nuclear translocation.
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Affiliation(s)
- Sojin An
- Department of Biological Chemistry, University of Michigan Medical School, Michigan, United States
| | - Jungmin Yoon
- Structural Biology Laboratory of Epigenetics, Department of Biological Sciences, Graduate school of Nanoscience and Technology (World Class University), KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Hanseong Kim
- Department of Biological Chemistry, University of Michigan Medical School, Michigan, United States
| | - Ji-Joon Song
- Structural Biology Laboratory of Epigenetics, Department of Biological Sciences, Graduate school of Nanoscience and Technology (World Class University), KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Uhn-Soo Cho
- Department of Biological Chemistry, University of Michigan Medical School, Michigan, United States
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30
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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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31
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Soniat M, Cağatay T, Chook YM. Recognition Elements in the Histone H3 and H4 Tails for Seven Different Importins. J Biol Chem 2016; 291:21171-21183. [PMID: 27528606 DOI: 10.1074/jbc.m116.730218] [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: 03/30/2016] [Indexed: 12/12/2022] Open
Abstract
N-terminal tails of histones H3 and H4 are known to bind several different Importins to import the histones into the cell nucleus. However, it is not known what binding elements in the histone tails are recognized by the individual Importins. Biochemical studies of H3 and H4 tails binding to seven Importins, Impβ, Kapβ2, Imp4, Imp5, Imp7, Imp9, and Impα, show the H3 tail binding more tightly than the H4 tail. The H3 tail binds Kapβ2 and Imp5 with KD values of 77 and 57 nm, respectively, and binds the other five Importins more weakly. Mutagenic analysis shows H3 tail residues 11-27 to be the sole binding segment for Impβ, Kapβ2, and Imp4. However, Imp5, Imp7, Imp9, and Impα bind two separate elements in the H3 tail: the segment at residues 11-27 and an isoleucine-lysine nuclear localization signal (IK-NLS) motif at residues 35-40. The H4 tail also uses either one or two basic segments to bind the same set of Importins with a similar trend of relative affinities as the H3 tail, albeit at least 10-fold weaker. Of the many lysine residues in the H3 and H4 tails, only acetylation of the H3 Lys14 substantially decreased binding to several Importins. Lastly, we show that, in addition to the N-terminal tails, the histone fold domains of H3 and H4 and/or the histone chaperone Asf1b are important for Importin-histone recognition.
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Affiliation(s)
- Michael Soniat
- From the Department of Pharmacology, University of Texas Southwestern, Dallas, Texas 75390
| | - Tolga Cağatay
- From the Department of Pharmacology, University of Texas Southwestern, Dallas, Texas 75390
| | - Yuh Min Chook
- From the Department of Pharmacology, University of Texas Southwestern, Dallas, Texas 75390
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