1
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Huang Y, Urban C, Hubel P, Stukalov A, Pichlmair A. Protein turnover regulation is critical for influenza A virus infection. Cell Syst 2024:S2405-4712(24)00268-0. [PMID: 39368468 DOI: 10.1016/j.cels.2024.09.004] [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: 12/19/2023] [Revised: 08/16/2024] [Accepted: 09/13/2024] [Indexed: 10/07/2024]
Abstract
The abundance of a protein is defined by its continuous synthesis and degradation, a process known as protein turnover. Here, we systematically profiled the turnover of proteins in influenza A virus (IAV)-infected cells using a pulse-chase stable isotope labeling by amino acids in cell culture (SILAC)-based approach combined with downstream statistical modeling. We identified 1,798 virus-affected proteins with turnover changes (tVAPs) out of 7,739 detected proteins (data available at pulsechase.innatelab.org). In particular, the affected proteins were involved in RNA transcription, splicing and nuclear transport, protein translation and stability, and energy metabolism. Many tVAPs appeared to be known IAV-interacting proteins that regulate virus propagation, such as KPNA6, PPP6C, and POLR2A. Notably, our analysis identified additional IAV host and restriction factors, such as the splicing factor GPKOW, that exhibit significant turnover rate changes while their total abundance is minimally affected. Overall, we show that protein turnover is a critical factor both for virus replication and antiviral defense.
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Affiliation(s)
- Yiqi Huang
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Christian Urban
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Philipp Hubel
- Core Facility Hohenheim, Universität Hohenheim, Stuttgart, Germany
| | - Alexey Stukalov
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Andreas Pichlmair
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany; Institute of Virology, Helmholtz Munich, Munich, Germany; German Centre for Infection Research (DZIF), Partner Site, Munich, Germany.
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2
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Jafarinia H, van der Giessen E, Onck PR. C9orf72 polyPR directly binds to various nuclear transport components. eLife 2024; 12:RP89694. [PMID: 38483313 PMCID: PMC10939497 DOI: 10.7554/elife.89694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024] Open
Abstract
The disruption of nucleocytoplasmic transport (NCT) is an important mechanism in neurodegenerative diseases. In the case of C9orf72-ALS, trafficking of macromolecules through the nuclear pore complex (NPC) might get frustrated by the binding of C9orf72-translated arginine-containing dipeptide repeat proteins (R-DPRs) to the Kapβ family of nuclear transport receptors. Besides Kapβs, several other types of transport components have been linked to NCT impairments in R-DPR-expressed cells, but the molecular origin of these observations has not been clarified. Here, we adopt a coarse-grained molecular dynamics model at amino acid resolution to study the direct interaction between polyPR, the most toxic DPR, and various nuclear transport components to elucidate the binding mechanisms and provide a complete picture of potential polyPR-mediated NCT defects. We found polyPR to directly bind to several isoforms of the Impα family, CAS (the specific exporter of Impα) and RanGAP. We observe no binding between polyPR and Ran. Longer polyPRs at lower salt concentrations also make contact with RanGEF and NTF2. Analyzing the polyPR contact sites on the transport components reveals that polyPR potentially interferes with RanGTP/RanGDP binding, with nuclear localization signal (NLS)-containing cargoes (cargo-NLS) binding to Impα, with cargo-NLS release from Impα, and with Impα export from the nucleus. The abundance of polyPR-binding sites on multiple transport components combined with the inherent polyPR length dependence makes direct polyPR interference of NCT a potential mechanistic pathway of C9orf72 toxicity.
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Affiliation(s)
- Hamidreza Jafarinia
- Zernike Institute for Advanced Materials, University of GroningenGroningenNetherlands
| | - Erik van der Giessen
- Zernike Institute for Advanced Materials, University of GroningenGroningenNetherlands
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of GroningenGroningenNetherlands
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3
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Hoad M, Roby JA, Forwood JK. Structural basis for nuclear import of bat adeno-associated virus capsid protein. J Gen Virol 2024; 105:001960. [PMID: 38441555 PMCID: PMC10999750 DOI: 10.1099/jgv.0.001960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 01/22/2024] [Indexed: 03/07/2024] Open
Abstract
Adeno-associated viruses (AAV) are one of the world's most promising gene therapy vectors and as a result, are one of the most intensively studied viral vectors. Despite a wealth of research into these vectors, the precise characterisation of AAVs to translocate into the host cell nucleus remains unclear. Recently we identified the nuclear localization signals of an AAV porcine strain and determined its mechanism of binding to host importin proteins. To expand our understanding of diverse AAV import mechanisms we sought to determine the mechanism in which the Cap protein from a bat-infecting AAV can interact with transport receptor importins for translocation into the nucleus. Using a high-resolution crystal structure and quantitative assays, we were able to not only determine the exact region and residues of the N-terminal domain of the Cap protein which constitute the functional NLS for binding with the importin alpha two protein, but also reveal the differences in binding affinity across the importin-alpha isoforms. Collectively our results allow for a detailed molecular view of the way AAV Cap proteins interact with host proteins for localization into the cell nucleus.
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Affiliation(s)
- Mikayla Hoad
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Justin A. Roby
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
- Gulbali Institute, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Jade K. Forwood
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
- Gulbali Institute, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
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4
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Cross EM, Akbari N, Ghassabian H, Hoad M, Pavan S, Ariawan D, Donnelly CM, Lavezzo E, Petersen GF, Forwood JK, Alvisi G. A functional and structural comparative analysis of large tumor antigens reveals evolution of different importin α-dependent nuclear localization signals. Protein Sci 2024; 33:e4876. [PMID: 38108201 PMCID: PMC10807245 DOI: 10.1002/pro.4876] [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: 09/19/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 12/19/2023]
Abstract
Nucleocytoplasmic transport regulates the passage of proteins between the nucleus and cytoplasm. In the best characterized pathway, importin (IMP) α bridges cargoes bearing basic, classical nuclear localization signals (cNLSs) to IMPβ1, which mediates transport through the nuclear pore complex. IMPα recognizes three types of cNLSs via two binding sites: the major binding site accommodates monopartite cNLSs, the minor binding site recognizes atypical cNLSs, while bipartite cNLSs simultaneously interact with both major and minor sites. Despite the growing knowledge regarding IMPα-cNLS interactions, our understanding of the evolution of cNLSs is limited. We combined bioinformatic, biochemical, functional, and structural approaches to study this phenomenon, using polyomaviruses (PyVs) large tumor antigens (LTAs) as a model. We characterized functional cNLSs from all human (H)PyV LTAs, located between the LXCXE motif and origin binding domain. Surprisingly, the prototypical SV40 monopartite NLS is not well conserved; HPyV LTA NLSs are extremely heterogenous in terms of structural organization, IMPα isoform binding, and nuclear targeting abilities, thus influencing the nuclear accumulation properties of full-length proteins. While several LTAs possess bipartite cNLSs, merkel cell PyV contains a hybrid bipartite cNLS whose upstream stretch of basic amino acids can function as an atypical cNLS, specifically binding to the IMPα minor site upon deletion of the downstream amino acids after viral integration in the host genome. Therefore, duplication of a monopartite cNLS and subsequent accumulation of point mutations, optimizing interaction with distinct IMPα binding sites, led to the evolution of bipartite and atypical NLSs binding at the minor site.
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Affiliation(s)
- Emily M. Cross
- School of Dentistry and Medical SciencesCharles Sturt UniversityWagga WaggaAustralia
- Diamond Light SourceHarwell Science and Innovation CampusDidcotUnited Kingdom
| | - Nasim Akbari
- Department of Molecular MedicineUniversity of PadovaPadovaItaly
| | | | - Mikayla Hoad
- School of Dentistry and Medical SciencesCharles Sturt UniversityWagga WaggaAustralia
| | - Silvia Pavan
- Department of Molecular MedicineUniversity of PadovaPadovaItaly
| | - Daryl Ariawan
- Dementia Research CentreMacquarie UniversitySydneyAustralia
| | - Camilla M. Donnelly
- School of Dentistry and Medical SciencesCharles Sturt UniversityWagga WaggaAustralia
| | - Enrico Lavezzo
- Department of Molecular MedicineUniversity of PadovaPadovaItaly
| | | | - Jade K. Forwood
- School of Dentistry and Medical SciencesCharles Sturt UniversityWagga WaggaAustralia
- Gulbali InstituteCharles Sturt UniversityWagga WaggaAustralia
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5
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Moraes IR, de Oliveira HC, Fontes MRM. Structural basis of nuclear transport for NEIL DNA glycosylases mediated by importin-alpha. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2024; 1872:140974. [PMID: 38065227 DOI: 10.1016/j.bbapap.2023.140974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/18/2023] [Accepted: 11/30/2023] [Indexed: 01/10/2024]
Abstract
NEIL glycosylases, including NEIL1, NEIL2, and NEIL3, play a crucial role in the base excision DNA repair pathway (BER). The classical importin pathway mediated by importin α/β and cargo proteins containing nuclear localization sequences (NLS) is the most common transport mechanism of DNA repair proteins to the nucleus. Previous studies have identified putative NLSs located at the C-terminus of NEIL3 and NEIL1. Crystallographic, bioinformatics, calorimetric (ITC), and fluorescence assays were used to investigate the interaction between NEIL1 and NEIL3 putative NLSs and importin-α (Impα). Our findings showed that NEIL3 contains a typical cNLS, with medium affinity for the major binding site of Impα. In contrast, crystallographic analysis of NEIL1 NLS revealed its binding to Impα, but with high B-factors and a lack of electron density at the linker region. ITC and fluorescence assays indicated no detectable affinity between NEIL1 NLS and Impα. These data suggest that NEIL1 NLS is a non-classical NLS with low affinity to Impα. Additionally, we compared the binding mode of NEIL3 and NEIL1 with Mus musculus Impα to human isoforms HsImpα1 and HsImpα3, which revealed interesting binding differences for HsImpα3 variant. NEIL3 is a classical medium affinity monopartite NLS, while NEIL1 is likely to be an unclassical low-affinity bipartite NLS. The base excision repair pathway is one of the primary systems involved in repairing DNA. Thus, understanding the mechanisms of nuclear transport of NEIL proteins is crucial for comprehending the role of these proteins in DNA repair and disease development.
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Affiliation(s)
- Ivan R Moraes
- Departamento de Biofísica e Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Hamine C de Oliveira
- Departamento de Biofísica e Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Marcos R M Fontes
- Departamento de Biofísica e Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil; Instituto de Estudos Avançados do Mar (IEAMar), Universidade Estadual Paulista (UNESP), São Vicente, SP, Brazil.
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6
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Goswami R, Gupta A, Bednova O, Coulombe G, Patel D, Rotello VM, Leyton JV. Nuclear localization signal-tagged systems: relevant nuclear import principles in the context of current therapeutic design. Chem Soc Rev 2024; 53:204-226. [PMID: 38031452 PMCID: PMC10798298 DOI: 10.1039/d1cs00269d] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Nuclear targeting of therapeutics provides a strategy for enhancing efficacy of molecules active in the nucleus and minimizing off-target effects. 'Active' nuclear-directed transport and efficient translocations across nuclear pore complexes provide the most effective means of maximizing nuclear localization. Nuclear-targeting systems based on nuclear localization signal (NLS) motifs have progressed significantly since the beginning of the current millennium. Here, we offer a roadmap for understanding the basic mechanisms of nuclear import in the context of actionable therapeutic design for developing NLS-therapeutics with improved treatment efficacy.
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Affiliation(s)
- Ritabrita Goswami
- Department of Chemistry, University of Massachusetts, Massachusetts, USA.
| | - Aarohi Gupta
- Department of Chemistry, University of Massachusetts, Massachusetts, USA.
| | - Olga Bednova
- Département de médecine nucléaire et radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Québec, Canada
| | - Gaël Coulombe
- Service des stages et du développement professionnel, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Dipika Patel
- Service des stages et du développement professionnel, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Vincent M Rotello
- Department of Chemistry, University of Massachusetts, Massachusetts, USA.
| | - Jeffrey V Leyton
- École des sciences pharmaceutiques, Université d'Ottawa, Ottawa, Ontario, Canada.
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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7
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Gilbertson B, Duncan M, Subbarao K. Role of the viral polymerase during adaptation of influenza A viruses to new hosts. Curr Opin Virol 2023; 62:101363. [PMID: 37672875 DOI: 10.1016/j.coviro.2023.101363] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 08/15/2023] [Accepted: 08/15/2023] [Indexed: 09/08/2023]
Abstract
As a group, influenza-A viruses (IAV) infect a wide range of animal hosts, however, they are constrained to infecting selected host species by species-specific interactions between the host and virus, that are required for efficient replication of the viral RNA genome. When IAV cross the species barrier, they acquire mutations in the viral genome to enable interactions with the new host factors, or to compensate for their loss. The viral polymerase genes polymerase basic 1, polymerase basic 2, and polymerase-acidic are important sites of host adaptation. In this review, we discuss why the viral polymerase is so vital to the process of host adaptation, look at some of the known viral mutations, and host factors involved in adaptation, particularly of avian IAV to mammalian hosts.
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Affiliation(s)
- Brad Gilbertson
- Department of Microbiology and Immunology, University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Melanie Duncan
- WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Kanta Subbarao
- Department of Microbiology and Immunology, University of Melbourne, at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; WHO Collaborating Centre for Reference and Research on Influenza, Victorian Infectious Diseases Reference Laboratory at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.
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8
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Bhambid M, Dey V, Walunj S, Patankar S. Toxoplasma Gondii Importin α Shows Weak Auto-Inhibition. Protein J 2023:10.1007/s10930-023-10128-2. [PMID: 37284905 DOI: 10.1007/s10930-023-10128-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2023] [Indexed: 06/08/2023]
Abstract
Importin α is a nuclear transporter that binds to nuclear localization signals (NLSs), consisting of 7-20 positively charged amino acids found within cargo proteins. In addition to cargo binding, intramolecular interactions also occur within the importin α protein due to binding between the importin β-binding (IBB) domain and the NLS-binding sites, a phenomenon called auto-inhibition. The interactions causing auto-inhibition are driven by a stretch of basic residues, similar to an NLS, in the IBB domain. Consistent with this, importin α proteins that do not have some of these basic residues lack auto-inhibition; a naturally occurring example of such a protein is found in the apicomplexan parasite Plasmodium falciparum. In this report, we show that importin α from another apicomplexan parasite, Toxoplasma gondii, harbors basic residues (KKR) in the IBB domain and exhibits auto-inhibition. This protein has a long, unstructured hinge motif (between the IBB domain and the NLS-binding sites) that does not contribute to auto-inhibition. However, the IBB domain may have a higher propensity to form an α-helical structure, positioning the wild-type KKR motif in an orientation that results in weaker interactions with the NLS-binding site than a KRR mutant. We conclude that the importin α protein from T. gondii shows auto-inhibition, exhibiting a different phenotype from that of P. falciparum importin α. However, our data indicate that T. gondii importin α may have a low strength of auto-inhibition. We hypothesize that low levels of auto-inhibition may confer an advantage to these important human pathogens.
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Affiliation(s)
- Manasi Bhambid
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Vishakha Dey
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
- Indiana University School of Medicine, Indianapolis, USA
| | - Sujata Walunj
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- IITB-Monash Research Academy, IIT Bombay, Mumbai, India
| | - Swati Patankar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India.
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9
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Donnelly CM, Vogel OA, Edwards MR, Taylor PE, Roby JA, Forwood JK, Basler CF. Henipavirus Matrix Protein Employs a Non-Classical Nuclear Localization Signal Binding Mechanism. Viruses 2023; 15:1302. [PMID: 37376602 DOI: 10.3390/v15061302] [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: 05/05/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 06/29/2023] Open
Abstract
Nipah virus (NiV) and Hendra virus (HeV) are highly pathogenic species from the Henipavirus genus within the paramyxovirus family and are harbored by Pteropus Flying Fox species. Henipaviruses cause severe respiratory disease, neural symptoms, and encephalitis in various animals and humans, with human mortality rates exceeding 70% in some NiV outbreaks. The henipavirus matrix protein (M), which drives viral assembly and budding of the virion, also performs non-structural functions as a type I interferon antagonist. Interestingly, M also undergoes nuclear trafficking that mediates critical monoubiquitination for downstream cell sorting, membrane association, and budding processes. Based on the NiV and HeV M X-ray crystal structures and cell-based assays, M possesses a putative monopartite nuclear localization signal (NLS) (residues 82KRKKIR87; NLS1 HeV), positioned on an exposed flexible loop and typical of how many NLSs bind importin alpha (IMPα), and a putative bipartite NLS (244RR-10X-KRK258; NLS2 HeV), positioned within an α-helix that is far less typical. Here, we employed X-ray crystallography to determine the binding interface of these M NLSs and IMPα. The interaction of both NLS peptides with IMPα was established, with NLS1 binding the IMPα major binding site, and NLS2 binding as a non-classical NLS to the minor site. Co-immunoprecipitation (co-IP) and immunofluorescence assays (IFA) confirm the critical role of NLS2, and specifically K258. Additionally, localization studies demonstrated a supportive role for NLS1 in M nuclear localization. These studies provide additional insight into the critical mechanisms of M nucleocytoplasmic transport, the study of which can provide a greater understanding of viral pathogenesis and uncover a potential target for novel therapeutics for henipaviral diseases.
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Affiliation(s)
- Camilla M Donnelly
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Olivia A Vogel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Megan R Edwards
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
- School of Population and Public Health, Faculty of Medicine, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Paige E Taylor
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Justin A Roby
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Jade K Forwood
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Christopher F Basler
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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10
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Alvisi G, Manaresi E, Cross EM, Hoad M, Akbari N, Pavan S, Ariawan D, Bua G, Petersen GF, Forwood J, Gallinella G. Importin α/β-dependent nuclear transport of human parvovirus B19 nonstructural protein 1 is essential for viral replication. Antiviral Res 2023; 213:105588. [PMID: 36990397 DOI: 10.1016/j.antiviral.2023.105588] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/08/2023] [Accepted: 03/25/2023] [Indexed: 03/30/2023]
Abstract
Human parvovirus B19 (B19V) is a major human pathogen causing a variety of diseases, characterized by a selective tropism to human progenitor cells in bone marrow. In similar fashion to all Parvoviridae members, the B19V ssDNA genome is replicated within the nucleus of infected cells through a process which involves both cellular and viral proteins. Among the latter, a crucial role is played by non-structural protein (NS)1, a multifunctional protein involved in genome replication and transcription, as well as modulation of host gene expression and function. Despite the localization of NS1 within the host cell nucleus during infection, little is known regarding the mechanism of its nuclear transport pathway. In this study we undertake structural, biophysical, and cellular approaches to characterize this process. Quantitative confocal laser scanning microscopy (CLSM), gel mobility shift, fluorescence polarization and crystallographic analysis identified a short sequence of amino acids (GACHAKKPRIT-182) as the classical nuclear localization signal (cNLS) responsible for nuclear import, mediated in an energy and importin (IMP) α/β-dependent fashion. Structure-guided mutagenesis of key residue K177 strongly impaired IMPα binding, nuclear import, and viral gene expression in a minigenome system. Further, treatment with ivermectin, an antiparasitic drug interfering with the IMPα/β dependent nuclear import pathway, inhibited NS1 nuclear accumulation and viral replication in infected UT7/Epo-S1 cells. Thus, NS1 nuclear transport is a potential target of therapeutic intervention against B19V induced disease.
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Affiliation(s)
- Gualtiero Alvisi
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy.
| | - Elisabetta Manaresi
- Department of Pharmacy and Biotechnology, University of Bologna, 40138, Bologna, Italy
| | - Emily M Cross
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2650, Australia
| | - Mikayla Hoad
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2650, Australia
| | - Nasim Akbari
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Silvia Pavan
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Daryl Ariawan
- Dementia Research Centre, Macquarie University, Sydney, NSW, 2109, Australia
| | - Gloria Bua
- Department of Pharmacy and Biotechnology, University of Bologna, 40138, Bologna, Italy
| | - Gayle F Petersen
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2650, Australia
| | - Jade Forwood
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2650, Australia
| | - Giorgio Gallinella
- Department of Pharmacy and Biotechnology, University of Bologna, 40138, Bologna, Italy
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11
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The ubiquitination landscape of the influenza A virus polymerase. Nat Commun 2023; 14:787. [PMID: 36774438 PMCID: PMC9922279 DOI: 10.1038/s41467-023-36389-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 01/30/2023] [Indexed: 02/13/2023] Open
Abstract
During influenza A virus (IAV) infections, viral proteins are targeted by cellular E3 ligases for modification with ubiquitin. Here, we decipher and functionally explore the ubiquitination landscape of the IAV polymerase proteins during infection of human alveolar epithelial cells by applying mass spectrometry analysis of immuno-purified K-ε-GG (di-glycyl)-remnant-bearing peptides. We have identified 59 modified lysines across the three subunits, PB2, PB1 and PA of the viral polymerase of which 17 distinctively affect mRNA transcription, vRNA replication and the generation of recombinant viruses via non-proteolytic mechanisms. Moreover, further functional and in silico analysis indicate that ubiquitination at K578 in the PB1 thumb domain is mechanistically linked to dynamic structural transitions of the viral polymerase that are required for vRNA replication. Mutations K578A and K578R differentially affect the generation of recombinant viruses by impeding cRNA and vRNA synthesis, NP binding as well as polymerase dimerization. Collectively, our results demonstrate that the ubiquitin-mediated charge neutralization at PB1-K578 disrupts the interaction to an unstructured loop in the PB2 N-terminus that is required to coordinate polymerase dimerization and facilitate vRNA replication. This provides evidence that IAV exploits the cellular ubiquitin system to modulate the activity of the viral polymerase for viral replication.
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12
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Nakanishi A, Okumura H, Hashita T, Yamashita A, Nishimura Y, Watanabe C, Kamimura S, Hayashi S, Murakami S, Ito K, Iwao T, Ikeda A, Hirose T, Sunazuka T, Tanaka Y, Matsunaga T. Ivermectin Inhibits HBV Entry into the Nucleus by Suppressing KPNA2. Viruses 2022; 14:v14112468. [PMID: 36366568 PMCID: PMC9695645 DOI: 10.3390/v14112468] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/28/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
Hepatitis B virus (HBV) specifically infects human hepatocytes and increases the risks of cirrhosis and liver cancer. Currently, nucleic acid analogs are the main therapeutics for chronic hepatitis caused by HBV infection. Although nucleic acid analogs can eliminate HBV DNA by inhibiting HBV reverse transcriptase, they cannot lead to negative conversion of covalently closed circular DNA (cccDNA) and hepatitis B surface antigen (HBsAg). In this study, we revealed that the antifilarial drug ivermectin suppresses HBV production by a different mechanism from the nucleic acid analog entecavir or Na+ taurocholate co-transporting polypeptide-mediated entry inhibitor cyclosporin A. Ivermectin reduced the levels of several HBV markers, including HBsAg, in HBV-infected human hepatocellular carcinoma cells (HepG2-hNTCP-C4 cells) and humanized mouse hepatocytes (PXB hepatocytes). In addition, ivermectin significantly decreased the expression of HBV core protein and the nuclear transporter karyopherin α2 (KPNA2) in the nuclei of HepG2-hNTCP-C4 cells. Furthermore, depletion of KPNA1-6 suppressed the production of cccDNA. These results suggest that KPNA1-6 is involved in the nuclear import of HBV and that ivermectin suppresses the nuclear import of HBV by inhibiting KPNA2. This study demonstrates the potential of ivermectin as a novel treatment for hepatitis B.
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Affiliation(s)
- Anna Nakanishi
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Hiroki Okumura
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Tadahiro Hashita
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
- Educational Research Center for Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
- Correspondence: (T.H.); (Y.T.)
| | - Aya Yamashita
- Educational Research Center for Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Yuka Nishimura
- Educational Research Center for Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Chihiro Watanabe
- Educational Research Center for Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Sakina Kamimura
- Educational Research Center for Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Sanae Hayashi
- Department of Virology and Liver Unit, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan
- Department of Gastroenterology and Hepatology, Kumamoto University, Kumamoto 860-8556, Japan
| | - Shuko Murakami
- Department of Virology and Liver Unit, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan
| | - Kyoko Ito
- Department of Virology and Liver Unit, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan
| | - Takahiro Iwao
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
- Educational Research Center for Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Akari Ikeda
- Ōmura Satoshi Memorial Institute, Graduate School of Infection Control Sciences, Kitasato University, Tokyo 108-8641, Japan
| | - Tomoyasu Hirose
- Ōmura Satoshi Memorial Institute, Graduate School of Infection Control Sciences, Kitasato University, Tokyo 108-8641, Japan
| | - Toshiaki Sunazuka
- Ōmura Satoshi Memorial Institute, Graduate School of Infection Control Sciences, Kitasato University, Tokyo 108-8641, Japan
| | - Yasuhito Tanaka
- Department of Virology and Liver Unit, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan
- Department of Gastroenterology and Hepatology, Kumamoto University, Kumamoto 860-8556, Japan
- Correspondence: (T.H.); (Y.T.)
| | - Tamihide Matsunaga
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
- Educational Research Center for Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
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13
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Doll SG, Meshkin H, Bryer AJ, Li F, Ko YH, Lokareddy RK, Gillilan RE, Gupta K, Perilla JR, Cingolani G. Recognition of the TDP-43 nuclear localization signal by importin α1/β. Cell Rep 2022; 39:111007. [PMID: 35767952 PMCID: PMC9290431 DOI: 10.1016/j.celrep.2022.111007] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 03/31/2022] [Accepted: 06/06/2022] [Indexed: 11/27/2022] Open
Abstract
Cytoplasmic mislocalization of the TAR-DNA binding protein of 43 kDa (TDP-43) leads to large, insoluble aggregates that are a hallmark of amyotrophic lateral sclerosis and frontotemporal dementia. Here, we study how importin α1/β recognizes TDP-43 bipartite nuclear localization signal (NLS). We find that the NLS makes extensive contacts with importin α1, especially at the minor NLS-binding site. NLS binding results in steric clashes with the C terminus of importin α1 that disrupts the TDP-43 N-terminal domain (NTD) dimerization interface. A putative phosphorylation site in the proximity of TDP-43 R83 at the minor NLS site destabilizes binding to importins by reducing the NLS backbone dynamics. Based on these data, we explain the pathogenic role of several post-translational modifications and mutations in the proximity of TDP-43 minor NLS site that are linked to disease and shed light on the chaperone activity of importin α1/β.
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Affiliation(s)
- Steven G Doll
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St., Philadelphia, PA 19107, USA
| | - Hamed Meshkin
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Alexander J Bryer
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Fenglin Li
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St., Philadelphia, PA 19107, USA
| | - Ying-Hui Ko
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St., Philadelphia, PA 19107, USA
| | - Ravi K Lokareddy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St., Philadelphia, PA 19107, USA
| | - Richard E Gillilan
- Macromolecular Diffraction Facility, Cornell High Energy Synchrotron Source (MacCHESS), Cornell University, 161 Synchrotron Drive, Ithaca, NY 14853, USA
| | - Kushol Gupta
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Juan R Perilla
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust St., Philadelphia, PA 19107, USA.
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14
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Antiviral Activity and Mechanisms of Seaweeds Bioactive Compounds on Enveloped Viruses-A Review. Mar Drugs 2022; 20:md20060385. [PMID: 35736188 PMCID: PMC9228758 DOI: 10.3390/md20060385] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 12/13/2022] Open
Abstract
In the last decades, the interest in seaweed has significantly increased. Bioactive compounds from seaweed’s currently receive major attention from pharmaceutical companies as they express several interesting biological activities which are beneficial for humans. The structural diversity of seaweed metabolites provides diverse biological activities which are expressed through diverse mechanisms of actions. This review mainly focuses on the antiviral activity of seaweed’s extracts, highlighting the mechanisms of actions of some seaweed molecules against infection caused by different types of enveloped viruses: influenza, Lentivirus (HIV-1), Herpes viruses, and coronaviruses. Seaweed metabolites with antiviral properties can act trough different pathways by increasing the host’s defense system or through targeting and blocking virus replication before it enters host cells. Several studies have already established the large antiviral spectrum of seaweed’s bioactive compounds. Throughout this review, antiviral mechanisms and medical applications of seaweed’s bioactive compounds are analyzed, suggesting seaweed’s potential source of antiviral compounds for the formulation of novel and natural antiviral drugs.
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15
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G Protein Subunit β1 Facilitates Influenza A Virus Replication by Promoting the Nuclear Import of PB2. J Virol 2022; 96:e0049422. [PMID: 35604143 DOI: 10.1128/jvi.00494-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
G protein subunit β1 (GNB1), the beta subunit of the G protein family, plays an important role in regulating transmembrane signal transduction. Although a recent study has demonstrated that GNB1 can bind the matrix protein 1 (M1) to facilitate M1 transport to budding sites and promote the release of progeny influenza A virus (IAV), whether the GNB1 protein has other functions in IAV replication requires further study. Here, we found that GNB1 promoted IAV replication, as virus yield decreased in GNB1 knockdown or knockout cells. GNB1 interacted with polymerase subunits PB2, PB1, and PA. Overexpressed GNB1 facilitated PB2 binding to importin α3, α5, and α7 promoting the nuclear import of PB2, enhancing viral RNA synthesis and polymerase activity. Altogether, our results demonstrated that GNB1 positively regulates virus replication by interacting with polymerase subunits and facilitating the nuclear import of PB2, which provide novel insights into the molecular mechanism of IAV. IMPORTANCE Until now, there has been only one article on the role of GNB1 in IAV budding. No study has investigated the role of GNB1 in IAV replication. In this study, our research demonstrated that GNB1 could increase the interaction between PB2 and the importin α isoform and mediate the nuclear import of PB2. Therefore, GNB1 could promote viral replication and transcription. Our results provide a better understanding of the molecular mechanisms of viral replication and provide potential antiviral drug targets.
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16
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MERS-CoV ORF4b employs an unusual binding mechanism to target IMPα and block innate immunity. Nat Commun 2022; 13:1604. [PMID: 35338144 PMCID: PMC8956657 DOI: 10.1038/s41467-022-28851-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 02/11/2022] [Indexed: 11/25/2022] Open
Abstract
The MERS coronavirus (MERS-CoV) is a highly pathogenic, emerging virus that produces accessory proteins to antagonize the host innate immune response. The MERS-CoV ORF4b protein has been shown to bind preferentially to the nuclear import adapter IMPα3 in infected cells, thereby inhibiting NF-κB-dependent innate immune responses. Here, we report high-resolution structures of ORF4b bound to two distinct IMPα family members. Each exhibit highly similar binding mechanisms that, in both cases, lack a prototypical Lys bound at their P2 site. Mutations within the NLS region dramatically alter the mechanism of binding, which reverts to the canonical P2 Lys binding mechanism. Mutational studies confirm that the novel binding mechanism is important for its nuclear import, IMPα interaction, and inhibition of innate immune signaling pathways. In parallel, we determined structures of the nuclear binding domain of NF-κB component p50 bound to both IMPα2 and α3, demonstrating that p50 overlaps with the ORF4b binding sites, suggesting a basis for inhibition. Our results provide a detailed structural basis that explains how a virus can target the IMPα nuclear import adapter to impair immunity, and illustrate how small mutations in ORF4b, like those found in closely related coronaviruses such as HKU5, change the IMPα binding mechanism. MERS-CoV ORF4b antagonizes host innate immune response, partially via blocking nuclear import adapter IMPα activity and preventing nuclear translocation of NF-κB. Here, Munasinghe and Edwards et al. biochemically and structurally define the interaction between ORF4b and IMPα-family members and find a non-canonical interaction between ORF4b NLS and IMPα2 and IMPα3.
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17
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Florio TJ, Lokareddy RK, Yeggoni DP, Sankhala RS, Ott CA, Gillilan RE, Cingolani G. Differential recognition of canonical NF-κB dimers by Importin α3. Nat Commun 2022; 13:1207. [PMID: 35260573 PMCID: PMC8904830 DOI: 10.1038/s41467-022-28846-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 02/11/2022] [Indexed: 11/09/2022] Open
Abstract
Nuclear translocation of the p50/p65 heterodimer is essential for NF-κB signaling. In unstimulated cells, p50/p65 is retained by the inhibitor IκBα in the cytoplasm that masks the p65-nuclear localization sequence (NLS). Upon activation, p50/p65 is translocated into the nucleus by the adapter importin α3 and the receptor importin β. Here, we describe a bipartite NLS in p50/p65, analogous to nucleoplasmin NLS but exposed in trans. Importin α3 accommodates the p50- and p65-NLSs at the major and minor NLS-binding pockets, respectively. The p50-NLS is the predominant binding determinant, while the p65-NLS induces a conformational change in the Armadillo 7 of importin α3 that stabilizes a helical conformation of the p65-NLS. Neither conformational change was observed for importin α1, which makes fewer bonds with the p50/p65 NLSs, explaining the preference for α3. We propose that importin α3 discriminates between the transcriptionally active p50/p65 heterodimer and p50/p50 and p65/65 homodimers, ensuring fidelity in NF-κB signaling. Nuclear translocation of the p50/p65 heterodimer is essential for NF-κB signaling. Here, the authors identify a bipartite Nuclear Localization Signal in the NF-κB p50/p65 heterodimer that is recognized with high affinity by importin α3.
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Affiliation(s)
- Tyler J Florio
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA
| | - Ravi K Lokareddy
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA
| | - Daniel P Yeggoni
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA
| | - Rajeshwer S Sankhala
- Center of Infectious Disease Research, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Connor A Ott
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA
| | - Richard E Gillilan
- Macromolecular Diffraction Facility, Cornell High Energy Synchrotron Source (MacCHESS), Cornell University, 161 Synchrotron Drive, Ithaca, NY, 14853, USA
| | - Gino Cingolani
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA, 19107, USA.
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18
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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: 121] [Impact Index Per Article: 60.5] [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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19
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Tsimbalyuk S, Donnelly CM, Forwood JK. Structural characterization of human importin alpha 7 in its cargo-free form at 2.5 Å resolution. Sci Rep 2022; 12:315. [PMID: 35013395 PMCID: PMC8748863 DOI: 10.1038/s41598-021-03729-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/24/2021] [Indexed: 11/22/2022] Open
Abstract
Shuttling of macromolecules between nucleus and cytoplasm is a tightly regulated process mediated through specific interactions between cargo and nuclear transport proteins. In the classical nuclear import pathway, importin alpha recognizes cargo exhibiting a nuclear localization signal, and this complex is transported through the nuclear pore complex by importin beta. Humans possess seven importin alpha isoforms that can be grouped into three subfamilies, with many cargoes displaying specificity towards these importin alpha isoforms. The cargo binding sites within importin alpha isoforms are highly conserved in sequence, suggesting that specificity potentially relies on structural differences. Structures of some importin alpha isoforms, both in cargo-bound and free states, have been previously solved. However, there are currently no known structures of cargo free importin alpha isoforms within subfamily 3 (importin alpha 5, 6, 7). Here, we present the first crystal structure of human importin alpha 7 lacking the IBB domain solved at 2.5 Å resolution. The structure reveals a typical importin alpha architecture comprised of ten armadillo repeats and is most structurally conserved with importin alpha 5. Very little difference in structure was observed between the cargo-bound and free states, implying that importin alpha 7 does not undergo conformational change when binding cargo. These structural insights provide a strong platform for further evaluation of structure–function relationships and understanding how isoform specificity within the importin alpha family plays a role in nuclear transport in health and disease.
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Affiliation(s)
- S Tsimbalyuk
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - C M Donnelly
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - J K Forwood
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia. .,School of Dentistry and Medical Sciences, Charles Sturt University, Room 2, National Life Sciences Hub, Wagga Wagga, NSW, 2678, Australia.
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20
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Jibiki K, Liu MY, Lei CS, Kodama TS, Kojima C, Fujiwara T, Yasuhara N. Biochemical propensity mapping for structural and functional anatomy of importin α IBB domain. Genes Cells 2021; 27:173-191. [PMID: 34954861 DOI: 10.1111/gtc.12917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 11/28/2022]
Abstract
Importin α has been described as a nuclear protein transport receptor that enables proteins synthesized in the cytoplasm to translocate into the nucleus. Besides its function in nuclear transport, an increasing number of studies have examined its non-nuclear transport functions. In both nuclear transport and non-nuclear transport, a functional domain called the IBB domain (importin β binding domain) plays a key role in regulating importin α behavior, and is a common interacting domain for multiple binding partners. However, it is not yet fully understood how the IBB domain interacts with multiple binding partners, which leads to the switching of importin α function. In this study, we have distinguished the location and propensities of amino acids important for each function of the importin α IBB domain by mapping the biochemical/physicochemical propensities of evolutionarily conserved amino acids of the IBB domain onto the structure associated with each function. We found important residues that are universally conserved for IBB functions across species and family members, in addition to those previously known, as well as residues that are presumed to be responsible for the differences in complex-forming ability among family members and for functional switching.
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Affiliation(s)
- Kazuya Jibiki
- Graduate School of Integrated Basic Sciences, Nihon University, Setagaya-ku, Tokyo, Japan
| | - Mo-Yan Liu
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Setagaya-ku, Tokyo, Japan
| | - Chao-Sen Lei
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Setagaya-ku, Tokyo, Japan
| | - Takashi S Kodama
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, Sita, Osaka, Japan
| | - Chojiro Kojima
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, Sita, Osaka, Japan.,Graduate School of Engineering Science, Yokohama National University, Yokohama, kanagawa, Japan
| | - Toshimichi Fujiwara
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, Sita, Osaka, Japan
| | - Noriko Yasuhara
- Graduate School of Integrated Basic Sciences, Nihon University, Setagaya-ku, Tokyo, Japan.,Department of Biosciences, College of Humanities and Sciences, Nihon University, Setagaya-ku, Tokyo, Japan
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21
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Zhang M, Liu M, Bai S, Zhao C, Li Z, Xu J, Zhang X. Influenza A Virus-Host Specificity: An Ongoing Cross-Talk Between Viral and Host Factors. Front Microbiol 2021; 12:777885. [PMID: 34803997 PMCID: PMC8602901 DOI: 10.3389/fmicb.2021.777885] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 10/19/2021] [Indexed: 11/13/2022] Open
Abstract
One big threat from influenza A viruses (IAVs) is that novel viruses emerge from mutation alongside reassortment. Some of them have gained the capability to transmit into human from the avian reservoir. Understanding the molecular events and the involved factors in breaking the cross-species barrier holds important implication for the surveillance and prevention of potential influenza outbreaks. In this review, we summarize recent progresses, including several ground-breaking findings, in how the interaction between host and viral factors, exemplified by the PB2 subunit of the influenza virus RNA polymerase co-opting host ANP32 protein to facilitate transcription and replication of the viral genome, shapes the evolution of IAVs from host specificity to cross-species infection.
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Affiliation(s)
- Miaomiao Zhang
- Scientific Research Center, Shanghai Public Health Clinical Center & Institutes of Biomedical Sciences, Key Laboratory of Medical Molecular Virology of Ministry of Education/Health, Shanghai Medical College, Fudan University, Shanghai, China.,Shanghai Veterinary Research Institute, Chinese Academic of Agricultural Sciences & Animal Influenza Virus Evolution and Pathogenesis Innovation Team of the Agricultural Science and Technology Innovation Team, Shanghai, China
| | - Mingbin Liu
- Scientific Research Center, Shanghai Public Health Clinical Center & Institutes of Biomedical Sciences, Key Laboratory of Medical Molecular Virology of Ministry of Education/Health, Shanghai Medical College, Fudan University, Shanghai, China
| | - Shimeng Bai
- Scientific Research Center, Shanghai Public Health Clinical Center & Institutes of Biomedical Sciences, Key Laboratory of Medical Molecular Virology of Ministry of Education/Health, Shanghai Medical College, Fudan University, Shanghai, China
| | - Chen Zhao
- Scientific Research Center, Shanghai Public Health Clinical Center & Institutes of Biomedical Sciences, Key Laboratory of Medical Molecular Virology of Ministry of Education/Health, Shanghai Medical College, Fudan University, Shanghai, China
| | - Zejun Li
- Shanghai Veterinary Research Institute, Chinese Academic of Agricultural Sciences & Animal Influenza Virus Evolution and Pathogenesis Innovation Team of the Agricultural Science and Technology Innovation Team, Shanghai, China
| | - Jianqing Xu
- Scientific Research Center, Shanghai Public Health Clinical Center & Institutes of Biomedical Sciences, Key Laboratory of Medical Molecular Virology of Ministry of Education/Health, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xiaoyan Zhang
- Scientific Research Center, Shanghai Public Health Clinical Center & Institutes of Biomedical Sciences, Key Laboratory of Medical Molecular Virology of Ministry of Education/Health, Shanghai Medical College, Fudan University, Shanghai, China
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22
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Staller E, Barclay WS. Host Cell Factors That Interact with Influenza Virus Ribonucleoproteins. Cold Spring Harb Perspect Med 2021; 11:a038307. [PMID: 32988980 PMCID: PMC8559542 DOI: 10.1101/cshperspect.a038307] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Influenza viruses hijack host cell factors at each stage of the viral life cycle. After host cell entry and endosomal escape, the influenza viral ribonucleoproteins (vRNPs) are released into the cytoplasm where the classical cellular nuclear import pathway is usurped for nuclear translocation of the vRNPs. Transcription takes place inside the nucleus at active host transcription sites, and cellular mRNA export pathways are subverted for export of viral mRNAs. Newly synthesized RNP components cycle back into the nucleus using various cellular nuclear import pathways and host-encoded chaperones. Replication of the negative-sense viral RNA (vRNA) into complementary RNA (cRNA) and back into vRNA requires complex interplay between viral and host factors. Progeny vRNPs assemble at the host chromatin and subsequently exit from the nucleus-processes orchestrated by sets of host and viral proteins. Finally, several host pathways appear to play a role in vRNP trafficking from the nuclear envelope to the plasma membrane for egress.
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Affiliation(s)
- Ecco Staller
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, St. Mary's Campus, London W2 1NY, United Kingdom
| | - Wendy S Barclay
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, St. Mary's Campus, London W2 1NY, United Kingdom
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23
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Abstract
Influenza polymerase (FluPol) plays a key role in the viral infection cycle by transcribing and replicating the viral genome. FluPol is a multifunctional, heterotrimeric enzyme with cap-binding, endonuclease, RNA-dependent RNA polymerase and polyadenylation activities. It performs its functions in the context of the viral ribonucleoprotein particle (RNP), wherein the template viral RNA is coated by multiple copies of viral nucleoprotein. Moreover, it interacts with a number of host proteins that are essential cofactors and, consequently, adaptive mutations in the polymerase are required for crossing the avian-human species barrier. In this review, we show how mechanistic understanding of how FluPol performs its multiple functions has greatly advanced over the last decade through determination of high-resolution structures by X-ray crystallography and cryo-electron microscopy. These have revealed not only the detailed architecture of FluPol but highlighted the remarkably conformational flexibility that is inherent to its functioning as a dynamic RNA synthesis machine. Structural studies are also underpinning current attempts to develop next-generation anti-influenza drugs that directly target FluPol.
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Affiliation(s)
- Joanna M Wandzik
- European Molecular Biology Laboratory, Grenoble 38042-Cedex 9, France
| | - Tomas Kouba
- European Molecular Biology Laboratory, Grenoble 38042-Cedex 9, France
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble 38042-Cedex 9, France
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24
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Acetylation, Methylation and Allysine Modification Profile of Viral and Host Proteins during Influenza A Virus Infection. Viruses 2021; 13:v13071415. [PMID: 34372620 PMCID: PMC8310381 DOI: 10.3390/v13071415] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/08/2021] [Accepted: 07/18/2021] [Indexed: 12/18/2022] Open
Abstract
Protein modifications dynamically occur and regulate biological processes in all organisms. Towards understanding the significance of protein modifications in influenza virus infection, we performed a global mass spectrometry screen followed by bioinformatics analyses of acetylation, methylation and allysine modification in human lung epithelial cells in response to influenza A virus infection. We discovered 8 out of 10 major viral proteins and 245 out of 2280 host proteins detected to be differentially modified by three modifications in infected cells. Some of the identified proteins were modified on multiple amino acids residues and by more than one modification; the latter occurred either on different or same residues. Most of the modified residues in viral proteins were conserved across >40 subtypes of influenza A virus, and influenza B or C viruses and located on the protein surface. Importantly, many of those residues have already been determined to be critical for the influenza A virus. Similarly, many modified residues in host proteins were conserved across influenza A virus hosts like humans, birds, and pigs. Finally, host proteins undergoing the three modifications clustered in common functional networks of metabolic, cytoskeletal, and RNA processes, all of which are known to be exploited by the influenza A virus.
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25
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Structural and calorimetric studies reveal specific determinants for the binding of a high-affinity NLS to mammalian importin-alpha. Biochem J 2021; 478:2715-2732. [PMID: 34195786 DOI: 10.1042/bcj20210401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/21/2021] [Accepted: 06/25/2021] [Indexed: 11/17/2022]
Abstract
The classical nuclear import pathway is mediated by importin (Impα and Impβ), which recognizes the cargo protein by its nuclear localization sequence (NLS). NLSs have been extensively studied resulting in different proposed consensus; however, recent studies showed that exceptions may occur. This mechanism may be also dependent on specific characteristics of different Impα. Aiming to better understand the importance of specific residues from consensus and adjacent regions of NLSs, we studied different mutations of a high-affinity NLS complexed to Impα by crystallography and calorimetry. We showed that although the consensus sequence allows Lys or Arg residues at the second residue of a monopartite sequence, the presence of Arg is very important to its binding in major and minor sites of Impα. Mutations in the N or C-terminus (position P1 or P6) of the NLS drastically reduces their affinity to the receptor, which is corroborated by the loss of hydrogen bonds and hydrophobic interactions. Surprisingly, a mutation in the far N-terminus of the NLS led to an increase in the affinity for both binding sites, corroborated by the structure with an additional hydrogen bond. The binding of NLSs to the human variant Impα1 revealed that these are similar to those found in structures presented here. For human variant Impα3, the bindings are only relevant for the major site. This study increases understanding of specific issues sparsely addressed in previous studies that are important to the task of predicting NLSs, which will be relevant in the eventual design of synthetic NLSs.
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26
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Massari S, Desantis J, Nizi MG, Cecchetti V, Tabarrini O. Inhibition of Influenza Virus Polymerase by Interfering with Its Protein-Protein Interactions. ACS Infect Dis 2021; 7:1332-1350. [PMID: 33044059 PMCID: PMC8204303 DOI: 10.1021/acsinfecdis.0c00552] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Influenza (flu) virus is a serious threat to global health with the potential to generate devastating pandemics. The availability of broad spectrum antiviral drugs is an unequaled weapon during pandemic events, especially when a vaccine is still not available. One of the most promising targets for the development of new antiflu therapeutics is the viral RNA-dependent RNA polymerase (RdRP). The assembly of the flu RdRP heterotrimeric complex from the individual polymerase acidic protein (PA), polymerase basic protein 1 (PB1), and polymerase basic protein 2 (PB2) subunits is a prerequisite for RdRP functions, such as mRNA synthesis and genome replication. In this Review, we report the known protein-protein interactions (PPIs) occurring by RdRP that could be disrupted by small molecules and analyze their benefits and drawbacks as drug targets. An overview of small molecules able to interfere with flu RdRP functions exploiting the PPI inhibition approach is described. In particular, an update on the most recent inhibitors targeting the well-consolidated RdRP PA-PB1 subunit heterodimerization is mainly reported, together with pioneer inhibitors targeting other virus-virus or virus-host interactions involving RdRP subunits. As demonstrated by the PA-PB1 interaction inhibitors discussed herein, the inhibition of flu RdRP functions by PPI disrupters clearly represents a valid means to identify compounds endowed with a broad spectrum of action and a reduced propensity to develop drug resistance, which are the main issues of antiviral drugs.
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Affiliation(s)
- Serena Massari
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Jenny Desantis
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123, Perugia, Italy
| | - Maria Giulia Nizi
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Violetta Cecchetti
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
| | - Oriana Tabarrini
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy
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Sajidah ES, Lim K, Wong RW. How SARS-CoV-2 and Other Viruses Build an Invasion Route to Hijack the Host Nucleocytoplasmic Trafficking System. Cells 2021; 10:1424. [PMID: 34200500 PMCID: PMC8230057 DOI: 10.3390/cells10061424] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 12/14/2022] Open
Abstract
The host nucleocytoplasmic trafficking system is often hijacked by viruses to accomplish their replication and to suppress the host immune response. Viruses encode many factors that interact with the host nuclear transport receptors (NTRs) and the nucleoporins of the nuclear pore complex (NPC) to access the host nucleus. In this review, we discuss the viral factors and the host factors involved in the nuclear import and export of viral components. As nucleocytoplasmic shuttling is vital for the replication of many viruses, we also review several drugs that target the host nuclear transport machinery and discuss their feasibility for use in antiviral treatment.
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Affiliation(s)
- Elma Sakinatus Sajidah
- Division of Nano Life Science in the Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan;
| | - Keesiang Lim
- WPI-Nano Life Science Institute, Kanazawa University, Kanazawa 920-1192, Japan
| | - Richard W. Wong
- Division of Nano Life Science in the Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan;
- WPI-Nano Life Science Institute, Kanazawa University, Kanazawa 920-1192, Japan
- Cell-Bionomics Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-1192, Japan
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28
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Mammalian cells use the autophagy process to restrict avian influenza virus replication. Cell Rep 2021; 35:109213. [PMID: 34107256 DOI: 10.1016/j.celrep.2021.109213] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/07/2021] [Accepted: 05/12/2021] [Indexed: 01/06/2023] Open
Abstract
Host adaptive mutations in the influenza A virus (IAV) PB2 protein are critical for human infection, but their molecular action is not well understood. We observe that when IAV containing avian PB2 infects mammalian cells, viral ribonucleoprotein (vRNP) aggregates that localize to the microtubule-organizing center (MTOC) are formed. These vRNP aggregates resemble LC3B-associated autophagosome structures, with aggresome-like properties, in that they cause the re-distribution of vimentin. However, electron microscopy reveals that these aggregates represent an accumulation of autophagic vacuoles. Compared to mammalian-PB2 virus, avian-PB2 virus induces higher autophagic flux in infected cells, indicating an increased rate of autophagosomes containing avian vRNPs fusing with lysosomes. We found that p62 is essential for the formation of vRNP aggregates and that the Raptor-interacting region of p62 is required for interaction with vRNPs through the PB2 polymerase subunit. Selective autophagic sequestration during late-stage virus replication is thus an additional strategy for host restriction of avian-PB2 IAV.
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29
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Panagiotopoulos AA, Polioudaki C, Ntallis SG, Dellis D, Notas G, Panagiotidis CA, Theodoropoulos PA, Castanas E, Kampa M. The sequence [EKRKI(E/R)(K/L/R/S/T)] is a nuclear localization signal for importin 7 binding (NLS7). Biochim Biophys Acta Gen Subj 2021; 1865:129851. [PMID: 33482249 DOI: 10.1016/j.bbagen.2021.129851] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 01/14/2021] [Accepted: 01/14/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND Nuclear translocation of large proteins is mediated through specific protein carriers, collectively named karyopherins (importins, exportins and adaptor proteins). Cargo proteins are recognized by importins through specific motifs, known as nuclear localization signals (NLS). However, only the NLS recognized by importin α and transportin (M9 NLS) have been identified so far METHODS: An unsupervised in silico approach was used, followed by experimental validation. RESULTS We identified the sequence EKRKI(E/R)(K/L/R/S/T) as an NLS signal for importin 7 recognition. This sequence was validated in the breast cancer cell line T47D, which expresses importin 7. Finally, we verified that importin 7-mediated nuclear protein transport is affected by cargo protein phosphorylation. CONCLUSIONS The NLS sequence for importin 7 was identified and we propose this approach as an identification method of novel specific NLS sequences for β-karyopherin family members. GENERAL SIGNIFICANCE Elucidating the complex relationships of the nuclear transporters and their cargo proteins may help in laying the foundation for the development of novel therapeutics, targeting specific importins, with an immediate translational impact.
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Affiliation(s)
| | - Chara Polioudaki
- Laboratory of Biochemistry, School of Medicine, University of Crete, 71013, Greece
| | - Sotirios G Ntallis
- Laboratory of Pharmacology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | | | - George Notas
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece
| | - Christos A Panagiotidis
- Laboratory of Pharmacology, School of Pharmacy, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | | | - Elias Castanas
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece.
| | - Marilena Kampa
- Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece.
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30
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Fareed FMA, Korulu S, Özbil M, Çapan ÖY. HNF1A-MODY Mutations in Nuclear Localization Signal Impair HNF1A-Import Receptor KPNA6 Interactions. Protein J 2021; 40:512-521. [PMID: 33459938 DOI: 10.1007/s10930-020-09959-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2020] [Indexed: 11/29/2022]
Abstract
Mutations in hepatocyte nuclear factor (HNF)1A gene cause the most common form of Maturity-onset diabetes of the young (MODY), a monogenic subtype of diabetes mellitus. Functional characterization of mutant proteins reveals that mutations may disrupt DNA binding capacity, transactivation ability and nuclear localization of HNF1A depending on the position of the mutation. Previously identified Arg271Trp and Ser345Tyr mutations in HNF1A were found to be defective in nuclear localization. Arg271 residue resides in a region similar to classical nuclear localization signal (NLS) motif, while Ser345 does not. Importin α family members recognize NLS motifs on cargo proteins and subsequently translocate them into nucleus. Here, we first investigated the nuclear localization mechanism of wild type HNF1A protein. For this purpose, we analyzed the interaction of HNF1A with three mouse homolog importin α proteins (KPNA2, KPNA4 and KPNA6) by co-immunoprecipitation assay and molecular docking simulation. Hereby, KPNA6 was identified as the main import receptor, which is responsible for the transport of HNF1A into the nucleus. Immunolocalization studies in mouse pancreatic cells (Min6) also confirmed the co-localization of HNF1A and KPNA6 in the cytoplasm. Secondly, the interaction between KPNA6 and mutant HNF1A proteins (Arg271Trp and Ser345Tyr) was assessed. Co-immunoprecipitation studies revealed a reduced interaction compared to wild type HNF1A. Our study demonstrated for the first time that HNF1A transcription factor is recognized and transported by importin/karyopherin import family, and mutations in NLS motifs may disrupt the interaction leading to nuclear localization abnormalities and MODY phenotype.
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Affiliation(s)
- Fareed M A Fareed
- Department of Molecular Biology and Genetics, İstanbul Arel University, 34537, Istanbul, Turkey.,Department of Chemistry, Yıldız Technical University, 34220, Istanbul, Turkey
| | - Sirin Korulu
- Institute of Natural and Health Sciences, Tallinn University, 10120, Tallinn, Estonia
| | - Mehmet Özbil
- Biotechnology Institute, Gebze Technical University, 41400, Kocaeli, Turkey
| | - Özlem Yalçın Çapan
- Department of Molecular Biology and Genetics, İstanbul Arel University, 34537, Istanbul, Turkey.
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31
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Jagga B, Edwards M, Pagin M, Wagstaff KM, Aragão D, Roman N, Nanson JD, Raidal SR, Dominado N, Stewart M, Jans DA, Hime GR, Nicolis SK, Basler CF, Forwood JK. Structural basis for nuclear import selectivity of pioneer transcription factor SOX2. Nat Commun 2021; 12:28. [PMID: 33397924 PMCID: PMC7782513 DOI: 10.1038/s41467-020-20194-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/26/2020] [Indexed: 12/17/2022] Open
Abstract
SOX (SRY-related HMG-box) transcription factors perform critical functions in development and cell differentiation. These roles depend on precise nuclear trafficking, with mutations in the nuclear targeting regions causing developmental diseases and a range of cancers. SOX protein nuclear localization is proposed to be mediated by two nuclear localization signals (NLSs) positioned within the extremities of the DNA-binding HMG-box domain and, although mutations within either cause disease, the mechanistic basis has remained unclear. Unexpectedly, we find here that these two distantly positioned NLSs of SOX2 contribute to a contiguous interface spanning 9 of the 10 ARM domains on the nuclear import adapter IMPα3. We identify key binding determinants and show this interface is critical for neural stem cell maintenance and for Drosophila development. Moreover, we identify a structural basis for the preference of SOX2 binding to IMPα3. In addition to defining the structural basis for SOX protein localization, these results provide a platform for understanding how mutations and post-translational modifications within these regions may modulate nuclear localization and result in clinical disease, and also how other proteins containing multiple NLSs may bind IMPα through an extended recognition interface. The SOX2 pioneer transcription factor performs critical roles in pluripotency and self-renewal of embryonic stem cells. Here the authors show that SOX2’s two nuclear localization signal sequences form a contiguous binding interface on the nuclear import receptor importin-α3, and provide a structural basis for the preference of SOX2 binding to IMPα3.
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Affiliation(s)
- Bikshapathi Jagga
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Megan Edwards
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, 30303, USA
| | - Miriam Pagin
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, piazza della Scienza 2, 20126, Milano, Italy
| | - Kylie M Wagstaff
- Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - David Aragão
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Noelia Roman
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Jeffrey D Nanson
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Shane R Raidal
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Nicole Dominado
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Murray Stewart
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - David A Jans
- Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Gary R Hime
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Silvia K Nicolis
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, piazza della Scienza 2, 20126, Milano, Italy
| | - Christopher F Basler
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, 30303, USA
| | - Jade K Forwood
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia.
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32
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Chang CC, Hsia KC. More than a zip code: global modulation of cellular function by nuclear localization signals. FEBS J 2020; 288:5569-5585. [PMID: 33296547 DOI: 10.1111/febs.15659] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/27/2022]
Abstract
Extensive structural and functional studies have been carried out in the field of nucleocytoplasmic transport. Nuclear transport factors, such as Importin-α/-β, recognize nuclear localization signals (NLSs) on cargo, and together with the small GTPase Ran, facilitate their nuclear localization. However, it is now emerging that binding of nuclear transport factors to NLSs not only mediates nuclear transport but also contributes to a variety of cellular functions in eukaryotes. Here, we describe recent advances that reveal how NLSs facilitate diverse cellular functions beyond nuclear transport activity. We review separately NLS-mediated regulatory mechanisms at different levels of biological organization, including (a) assembly of higher-order structures; (b) cellular organelle dynamics; and (c) modulation of cellular stress responses and viral infections. Finally, we provide mechanistic insights into how NLSs can regulate such a broad range of functions via their structural and biochemical properties.
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Affiliation(s)
- Chih-Chia Chang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Kuo-Chiang Hsia
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Institute of Biochemistry and Molecular Biology, College of Life Sciences, National Yang-Ming University, Taipei, Taiwan
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33
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Swine MicroRNAs ssc-miR-221-3p and ssc-miR-222 Restrict the Cross-Species Infection of Avian Influenza Virus. J Virol 2020; 94:JVI.01700-20. [PMID: 32907982 DOI: 10.1128/jvi.01700-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 08/30/2020] [Indexed: 11/20/2022] Open
Abstract
Avian influenza virus (AIV) can cross species barriers to infect humans and other mammals. However, these species-cross transmissions are most often dead-end infections due to host restriction. Current research about host restriction focuses mainly on the barriers of cell membrane, nuclear envelope, and host proteins; whether microRNAs (miRNAs) play a role in host restriction is largely unknown. In this study, we used porcine alveolar macrophage (PAM) cells as a model to elucidate the role of miRNAs in host range restriction. During AIV infection, 40 dysregulation expressed miRNAs were selected in PAM cells. Among them, two Sus scrofa (ssc; swine) miRNAs, ssc-miR-221-3p and ssc-miR-222, could inhibit the infection and replication of AIV in PAM cells by directly targeting viral genome and inducing cell apoptosis via inhibiting the expression of anti-apoptotic protein HMBOX1. Avian but not swine influenza virus caused upregulated expressions of ssc-miR-221-3p and ssc-miR-222 in PAM cells. We further found that NF-κB P65 was more effectively phosphorylated upon AIV infection and that P65 functioned as a transcription activator to regulate the AIV-induced expression of miR-221-3p/222 Importantly, we found that ssc-miR-221-3p and ssc-miR-222 could also be specifically upregulated upon AIV infection in newborn pig tracheal epithelial (NPTr) cells and also exerted anti-AIV function. In summary, our study indicated that miRNAs act as a host barrier during cross-species infection of influenza A virus.IMPORTANCE The host range of an influenza A virus is determined by species-specific interactions between virus and host cell factors. Host miRNAs can regulate influenza A virus replication; however, the role of miRNAs in host species specificity is unclear. Here, we show that the induced expression of ssc-miR-221-3p and ssc-miR-222 in swine cells is modulated by NF-κB P65 phosphorylation in response to AIV infection but not swine influenza virus infection. ssc-miR-221-3p and ssc-miR-222 exerted antiviral function via targeting viral RNAs and causing apoptosis by inhibiting the expression of HMBOX1 in host cells. These findings uncover miRNAs as a host range restriction factor that limits cross-species infection of influenza A virus.
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34
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A Phosphorylation-Induced Switch in the Nuclear Localization Sequence of the Intrinsically Disordered NUPR1 Hampers Binding to Importin. Biomolecules 2020; 10:biom10091313. [PMID: 32933064 PMCID: PMC7565984 DOI: 10.3390/biom10091313] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 09/05/2020] [Accepted: 09/09/2020] [Indexed: 12/24/2022] Open
Abstract
Several carrier proteins are involved in protein transport from the cytoplasm to the nucleus in eukaryotic cells. One of those is importin α, of which there are several human isoforms; among them, importin α3 (Impα3) has a high flexibility. The protein NUPR1, a nuclear protein involved in the cell-stress response and cell cycle regulation, is an intrinsically disordered protein (IDP) that has a nuclear localization sequence (NLS) to allow for nuclear translocation. NUPR1 does localize through the whole cell. In this work, we studied the affinity of the isolated wild-type NLS region (residues 54–74) of NUPR1 towards Impα3 and several mutants of the NLS region by using several biophysical techniques and molecular docking approaches. The NLS region of NUPR1 interacted with Impα3, opening the way to model the nuclear translocation of disordered proteins. All the isolated NLS peptides were disordered. They bound to Impα3 with low micromolar affinity (1.7–27 μM). Binding was hampered by removal of either Lys65 or Lys69 residues, indicating that positive charges were important; furthermore, binding decreased when Thr68 was phosphorylated. The peptide phosphorylated at Thr68, as well as four phospho-mimetic peptides (all containing the Thr68Glu mutation), showed the presence of a sequential NN(i,i + 1) nuclear Overhauser effect (NOE) in the 2D-1H-NMR (two-dimensional–proton NMR) spectra, indicating the presence of turn-like conformations. Thus, the phosphorylation of Thr68 modulates the binding of NUPR1 to Impα3 by a conformational, entropy-driven switch from a random-coil conformation to a turn-like structure.
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35
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Differential Behaviours and Preferential Bindings of Influenza Nucleoproteins on Importins-α. Viruses 2020; 12:v12080834. [PMID: 32751671 PMCID: PMC7472415 DOI: 10.3390/v12080834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/23/2020] [Accepted: 07/27/2020] [Indexed: 12/20/2022] Open
Abstract
Influenza viruses are negative single-stranded RNA viruses with nuclear transcription and replication. They enter the nucleus by using the cellular importin-α/-β nuclear import machinery. Influenza nucleoproteins from influenza A, B, C and D viruses possess a nuclear localization signal (NLS) localized on an intrinsically disordered extremity (NPTAIL). In this paper, using size exclusion chromatography (SEC), SEC-multi-angle laser light scattering (SEC-MALLS) analysis, surface plasmon resonance (SPR) and fluorescence anisotropy, we provide the first comparative study designed to dissect the interaction between the four NPTAILs and four importins-α identified as partners. All interactions between NPTAILs and importins-α have high association and dissociation rates and present a distinct and specific behaviour. D/NPTAIL interacts strongly with all importins-α while B/NPTAIL shows weak affinity for importins-α. A/NPTAIL and C/NPTAIL present preferential importin-α partners. Mutations in B/NPTAIL and D/NPTAIL show a loss of importin-α binding, confirming key NLS residues. Taken together, our results provide essential highlights of this complex translocation mechanism.
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36
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Characterization of the Importin-β binding domain in nuclear import receptor KPNA7. Biochem J 2020; 476:3413-3434. [PMID: 31642884 DOI: 10.1042/bcj20190717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 12/19/2022]
Abstract
The KPNA family of mammalian nuclear import receptors are encoded by seven genes that generate isoforms with 42-86% identity. KPNA isoforms have the same protein architecture and share the functional property of nuclear localization signal (NLS) recognition, however, the tissue and developmental expression patterns of these receptors raise the question of whether subtle differences in KPNA isoforms might be important in specific biological contexts. Here, we show that KPNA7, an isoform with expression mostly limited to early development, can bind Importin-β (Imp-β) in the absence of NLS cargo. This result contrasts with Imp-β interactions with other KPNA family members, where affinity is regulated by NLS cargo as part of a cooperative binding mechanism. The Imp-β binding (IBB) domain, which is highly conserved in all KPNA family members, generally serves to occlude the NLS binding groove and maintain the receptor in an auto-inhibited 'closed' state prior to NLS contact. Cooperative binding of NLS cargo and Imp-β to KPNA results in an 'open'state. Characterization of KPNA2-KPNA7 chimeric proteins suggests that features of both the IBB domain and the core structure of the receptor contribute to the extent of IBB domain accessibility for Imp-β binding, which likely reflects an 'open' state. We also provide evidence that KPNA7 maintains an open-state in the nucleus. We speculate that KPNA7 could function within the nucleus by interacting with NLS-containing proteins.
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37
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Thiele S, Stanelle-Bertram S, Beck S, Kouassi NM, Zickler M, Müller M, Tuku B, Resa-Infante P, van Riel D, Alawi M, Günther T, Rother F, Hügel S, Reimering S, McHardy A, Grundhoff A, Brune W, Osterhaus A, Bader M, Hartmann E, Gabriel G. Cellular Importin-α3 Expression Dynamics in the Lung Regulate Antiviral Response Pathways against Influenza A Virus Infection. Cell Rep 2020; 31:107549. [PMID: 32320654 PMCID: PMC7172908 DOI: 10.1016/j.celrep.2020.107549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/04/2020] [Accepted: 03/31/2020] [Indexed: 01/09/2023] Open
Abstract
Importin-α adaptor proteins orchestrate dynamic nuclear transport processes involved in cellular homeostasis. Here, we show that importin-α3, one of the main NF-κB transporters, is the most abundantly expressed classical nuclear transport factor in the mammalian respiratory tract. Importin-α3 promoter activity is regulated by TNF-α-induced NF-κB in a concentration-dependent manner. High-level TNF-α-inducing highly pathogenic avian influenza A viruses (HPAIVs) isolated from fatal human cases harboring human-type polymerase signatures (PB2 627K, 701N) significantly downregulate importin-α3 mRNA expression in primary lung cells. Importin-α3 depletion is restored upon back-mutating the HPAIV polymerase into an avian-type signature (PB2 627E, 701D) that can no longer induce high TNF-α levels. Importin-α3-deficient mice show reduced NF-κB-activated antiviral gene expression and increased influenza lethality. Thus, importin-α3 plays a key role in antiviral immunity against influenza. Lifting the bottleneck in importin-α3 availability in the lung might provide a new strategy to combat respiratory virus infections.
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Affiliation(s)
- Swantje Thiele
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Stephanie Stanelle-Bertram
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Sebastian Beck
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Nancy Mounogou Kouassi
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Martin Zickler
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Martin Müller
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Berfin Tuku
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Patricia Resa-Infante
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Debby van Riel
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany; Department of Viroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Malik Alawi
- Bioinformatics Service Facility, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Virus Genomics, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Thomas Günther
- Virus Genomics, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Franziska Rother
- Molecular Biology of Peptide Hormones, Max Delbrück Center for Molecular Medicine, Berlin, Germany; Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck, Germany
| | - Stefanie Hügel
- Molecular Biology of Peptide Hormones, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Susanne Reimering
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Alice McHardy
- Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Adam Grundhoff
- Virus Genomics, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Wolfram Brune
- Virus-Host Interaction, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Albert Osterhaus
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Michael Bader
- Molecular Biology of Peptide Hormones, Max Delbrück Center for Molecular Medicine, Berlin, Germany; Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck, Germany; Charité-Universitätsmedizin, Berlin, Germany
| | - Enno Hartmann
- Institute for Biology, Center for Structural and Cellular Biology in Medicine, University of Lübeck, Lübeck, Germany
| | - Gülsah Gabriel
- Viral Zoonosis - One Health, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany; Institute of Virology, University of Veterinary Medicine, Hannover, Germany.
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Díaz-García C, Hornos F, Giudici AM, Cámara-Artigas A, Luque-Ortega JR, Arbe A, Rizzuti B, Alfonso C, Forwood JK, Iovanna JL, Gómez J, Prieto M, Coutinho A, Neira JL. Human importin α3 and its N-terminal truncated form, without the importin-β-binding domain, are oligomeric species with a low conformational stability in solution. Biochim Biophys Acta Gen Subj 2020; 1864:129609. [PMID: 32234409 DOI: 10.1016/j.bbagen.2020.129609] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 03/13/2020] [Accepted: 03/26/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Eukaryotic cells have a continuous transit of macromolecules between the cytoplasm and the nucleus. Several carrier proteins are involved in this transport. One of them is importin α, which must form a complex with importin β to accomplish its function, by domain-swapping its 60-residue-long N terminus. There are several human isoforms of importin α; among them, importin α3 has a particularly high flexibility. METHODS We studied the conformational stability of intact importin α3 (Impα3) and its truncated form, where the 64-residue-long, N-terminal importin-β-binding domain (IBB) has been removed (ΔImpα3), in a wide pH range, with several spectroscopic, biophysical, biochemical methods and with molecular dynamics (MD). RESULTS Both species acquired native-like structure between pH 7 and 10.0, where Impα3 was a dimer (with an apparent self-association constant of ~10 μM) and ΔImpα3 had a higher tendency to self-associate than the intact species. The acquisition of secondary, tertiary and quaternary structure, and the burial of hydrophobic patches, occurred concomitantly. Both proteins unfolded irreversibly at physiological pH, by using either temperature or chemical denaturants, through several partially folded intermediates. The MD simulations support the presence of these intermediates. CONCLUSIONS The thermal stability of Impα3 at physiological pH was very low, but was higher than that of ΔImpα3. Both proteins were stable in a narrow pH range, and they unfolded at physiological pH populating several intermediate species. GENERAL SIGNIFICANCE The low conformational stability explains the flexibility of Impα3, which is needed to carry out its recognition of complex cargo sequences.
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Affiliation(s)
- Clara Díaz-García
- iBB- Institute for Bioengineering and Bioscience, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal
| | - Felipe Hornos
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain
| | | | - Ana Cámara-Artigas
- Departamento de Química y Física, Research Center CIAIMBITAL, Universidad de Almería- ceiA3, 04120 Almería, Spain
| | - Juan Román Luque-Ortega
- Centro de Investigaciones Biológicas Margarita Salas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Arantxa Arbe
- Centro de Física de Materiales (CFM) (CSIC-UPV/EHU), Materials Physics Center (MPC), 20018 San Sebastián, Spain
| | - Bruno Rizzuti
- CNR-NANOTEC, Licryl-UOS Cosenza and CEMIF.Cal, Department of Physics, University of Calabria, Via P. Bucci, Cubo 31 C, 87036 Arcavacata di Rende, Cosenza, Italy
| | - Carlos Alfonso
- Centro de Investigaciones Biológicas Margarita Salas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Jade K Forwood
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Juan L Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, 13288 Marseille, France
| | - Javier Gómez
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain
| | - Manuel Prieto
- iBB- Institute for Bioengineering and Bioscience, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal
| | - Ana Coutinho
- iBB- Institute for Bioengineering and Bioscience, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisboa, Portugal; Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1649-004 Lisboa, Portugal
| | - José L Neira
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos, Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain.
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39
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Kumar S, Yeo D, Harur Muralidharan N, Lai SK, Tong C, Tan BH, Sugrue RJ. Impaired Nuclear Export of the Ribonucleoprotein Complex and Virus-Induced Cytotoxicity Combine to Restrict Propagation of the A/Duck/Malaysia/02/2001 (H9N2) Virus in Human Airway Cells. Cells 2020; 9:cells9020355. [PMID: 32028682 PMCID: PMC7072679 DOI: 10.3390/cells9020355] [Citation(s) in RCA: 2] [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: 11/08/2019] [Revised: 01/20/2020] [Accepted: 01/29/2020] [Indexed: 01/02/2023] Open
Abstract
In humans, (A549) cells impaired H9N2 virus nuclear export of the ribonucleoprotein (RNP) complex contrasted with the early and efficient nuclear export of the H1N1/WSN and pH1N1 virus RNP complexes. Although nuclear export of the RNP complex occurred via the nuclear pore complex, H9N2 virus infection also induced modifications in the nuclear envelope and induced cell cytotoxicity. Reduced PA protein levels in H9N2 virus-infected A549 cells occurred, and this phenomenon was independent of virus infection. Silencing the H1N1/WSN PA protein expression leads to impaired nuclear export of RNP complexes, suggesting that the impaired nuclear export of the H9N2 virus RNP complex may be one of the consequences of reduced PA protein levels. Early and efficient export of the RNP complex occurred in H9N2 virus-infected avian (CEF) cells, although structural changes in the nuclear envelope also occurred. Collectively our data suggest that a combination of delayed nuclear export and virus-induced cell cytotoxicity restricts H9N2 virus transmission in A549 cells. However, the early and efficient export of the RNP complex mitigated the effects of virus-induced cytotoxicity on H9N2 virus transmission in CEF cells. Our findings highlight the multi-factorial nature of host-adaptation of the polymerase proteins of avian influenza viruses in non-avian cell environments.
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Affiliation(s)
- Sriram Kumar
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; (S.K.); (D.Y.); (N.H.M.); (S.K.L.); (C.T.)
| | - Dawn Yeo
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; (S.K.); (D.Y.); (N.H.M.); (S.K.L.); (C.T.)
- Detection and Diagnostics Laboratory, DSO National Laboratories, 27 Medical Drive, Singapore 117510, Singapore;
| | - Nisha Harur Muralidharan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; (S.K.); (D.Y.); (N.H.M.); (S.K.L.); (C.T.)
| | - Soak Kuan Lai
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; (S.K.); (D.Y.); (N.H.M.); (S.K.L.); (C.T.)
| | - Cathlyn Tong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; (S.K.); (D.Y.); (N.H.M.); (S.K.L.); (C.T.)
| | - Boon Huan Tan
- Detection and Diagnostics Laboratory, DSO National Laboratories, 27 Medical Drive, Singapore 117510, Singapore;
| | - Richard J. Sugrue
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; (S.K.); (D.Y.); (N.H.M.); (S.K.L.); (C.T.)
- Correspondence:
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40
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Llabrés S, Tsenkov MI, MacGowan SA, Barton GJ, Zachariae U. Disease related single point mutations alter the global dynamics of a tetratricopeptide (TPR) α-solenoid domain. J Struct Biol 2020; 209:107405. [PMID: 31628985 PMCID: PMC6961204 DOI: 10.1016/j.jsb.2019.107405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 10/04/2019] [Accepted: 10/15/2019] [Indexed: 01/18/2023]
Abstract
Tetratricopeptide repeat (TPR) proteins belong to the class of α-solenoid proteins, in which repetitive units of α-helical hairpin motifs stack to form superhelical, often highly flexible structures. TPR domains occur in a wide variety of proteins, and perform key functional roles including protein folding, protein trafficking, cell cycle control and post-translational modification. Here, we look at the TPR domain of the enzyme O-linked GlcNAc-transferase (OGT), which catalyses O-GlcNAcylation of a broad range of substrate proteins. A number of single-point mutations in the TPR domain of human OGT have been associated with the disease Intellectual Disability (ID). By extended steered and equilibrium atomistic simulations, we show that the OGT-TPR domain acts as an elastic nanospring, and that each of the ID-related local mutations substantially affect the global dynamics of the TPR domain. Since the nanospring character of the OGT-TPR domain is key to its function in binding and releasing OGT substrates, these changes of its biomechanics likely lead to defective substrate interaction. We find that neutral mutations in the human population, selected by analysis of the gnomAD database, do not incur these changes. Our findings may not only help to explain the ID phenotype of the mutants, but also aid the design of TPR proteins with tailored biomechanical properties.
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Affiliation(s)
- Salomé Llabrés
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, UK.
| | - Maxim I Tsenkov
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Stuart A MacGowan
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Geoffrey J Barton
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Ulrich Zachariae
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, UK; Physics, School of Science and Engineering, University of Dundee, Dundee, UK.
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41
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High-Throughput MicroRNA Profiles of Permissive Madin-Darby Canine Kidney Cell Line Infected with Influenza B Viruses. Viruses 2019; 11:v11110986. [PMID: 31717720 PMCID: PMC6893747 DOI: 10.3390/v11110986] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/15/2019] [Accepted: 10/23/2019] [Indexed: 12/14/2022] Open
Abstract
Victoria and Yamagata lineages of influenza B viruses are globally circulating in seasonal epidemics. Madin–Darby canine kidney (MDCK) cells are permissive for viral isolation and vaccine manufacture. Nevertheless, the interplay between influenza B viruses and host microRNAs has not been investigated in this cell line. Therefore, the present study aims at high-throughput analysis of canine microRNA profile upon infection of influenza B viruses. Briefly, MDCK cells were infected with Victoria or Yamagata lineage at MOI of 0.01. After being harvested at 6, 12 and 24 h post infection, microRNAs were subjected to high-throughput sequencing based on MiSeq platform (Illumina). The results demonstrated that five microRNAs including cfa-miR-197, cfa-miR-215, cfa-miR361, cfa-miR-1841, and cfa-miR-1842 were overexpressed in both Victoria and Yamagata lineage infections. Interestingly, computational prediction showed that karyopherin alpha 6 (KPNA6) was targeted by cfa-miR-197 and cfa-miR-215. Moreover, the binding sites of both microRNAs were assessed by 3′-UTR reporter assay. The results showed that only cfa-miR-197 could bind to the target sites of KPNA6, leading to suppressing luciferase activity. Additionally, silencing of KPNA6 was confirmed by overexpression of cfa-miR-197. This study provides canine microRNA responses to seasonal influenza B viruses, suggesting that virus-mediated microRNAs might play crucial roles in host gene regulation.
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42
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Liu X, Yang C, Sun X, Lin X, Zhao L, Chen H, Jin M. Evidence for a novel mechanism of influenza A virus host adaptation modulated by PB2-627. FEBS J 2019; 286:3389-3400. [PMID: 31034753 DOI: 10.1111/febs.14867] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 01/29/2019] [Accepted: 04/26/2019] [Indexed: 12/21/2022]
Abstract
Influenza virus cross-species transmission is restricted by the host, but viruses overcome this restriction by accumulating mutations which allow them to adapt to a new host. Among the many factors which facilitate virus host adaptation, polymerase basic protein 2 (PB2) 627 plays an important role, although the underlying molecular mechanism has not been fully understood. In a previous study, we found that histone H1.2 (encoded by HIST1H1C) regulates human or avian influenza virus replication in different ways, indicating that it might be involved in virus host adaptation. Herein, we found that HIST1H1C expression, phosphorylation and methylation levels are decreased when infected with H1N1 influenza virus and increased when infected with H5N1 influenza virus. Overexpressing the eight gene segments of the influenza virus, we found that only PB2 significantly affects HIST1H1C expression and modifications. Since the 627 site is different between the H5N1 and H1N1 influenza viruses we constructed PB2-627E (avian variant) and PB2-627K (human variant) mutant viruses, and observed that the effects of the wild-type and the mutant viruses on HIST1H1C expression and modifications are the opposite of one another. Further analysis showed that influenza virus PB2-627 regulates HIST1H1C expression via Sp1, and specifically that PB2-627K down-regulates Sp1 and HIST1H1C while PB2-627E up-regulates Sp1 and HIST1H1C. In addition, HIST1H1C can feedback regulate DNA-dependent protein kinase and euchromatic histone-lysine N-methyltransferase 1/2, leading to altered HIST1H1C phosphorylation and methylation levels, and affecting influenza virus replication accordingly. In summary, this study illustrates the mechanism of PB2-627E/K-mediated regulation of influenza virus host adaptation.
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Affiliation(s)
- Xiaokun Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Cha Yang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xiaomei Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xian Lin
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Lianzhong Zhao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.,College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Meilin Jin
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agro-Microbiology Resources Development - Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Animal Disease Diagnosis and Immunization - Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China.,College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
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43
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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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44
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Dawson WK, Lazniewski M, Plewczynski D. RNA structure interactions and ribonucleoprotein processes of the influenza A virus. Brief Funct Genomics 2019; 17:402-414. [PMID: 29040388 PMCID: PMC6252904 DOI: 10.1093/bfgp/elx028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In one more years, we will ‘celebrate’ an exact centenary of the Spanish flu pandemic. With the rapid evolution of the influenza virus, the possibility of novel pandemic remains ever a concern. This review covers our current knowledge of the influenza A virus: on the role of RNA in translation, replication, what is known of the expressed proteins and the protein products generated from alternative splicing, and on the role of base pairing in RNA structure. We highlight the main events associated with viral entry into the cell, the transcription and replication process, an export of the viral genetic material from the nucleus and the final release of the virus. We discuss the observed potential roles of RNA secondary structure (the RNA base-pairing arrangement) and RNA/RNA interactions in this scheme.
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Affiliation(s)
- Wayne K Dawson
- Bio-information Lab, University of Tokyo.,University of Warsaw, Center of New Technologies (CeNT), Warsaw, Poland
| | - Michal Lazniewski
- University of Warsaw, Center of New Technologies (CeNT), Warsaw, Poland
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45
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Resa-Infante P, Bonet J, Thiele S, Alawi M, Stanelle-Bertram S, Tuku B, Beck S, Oliva B, Gabriel G. Alternative interaction sites in the influenza A virus nucleoprotein mediate viral escape from the importin-α7 mediated nuclear import pathway. FEBS J 2019; 286:3374-3388. [PMID: 31044563 DOI: 10.1111/febs.14868] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 03/20/2019] [Accepted: 04/29/2019] [Indexed: 01/01/2023]
Abstract
Influenza A viruses are able to adapt to restrictive conditions due to their high mutation rates. Importin-α7 is a component of the nuclear import machinery required for avian-mammalian adaptation and replicative fitness in human cells. Here, we elucidate the mechanisms by which influenza A viruses may escape replicative restriction in the absence of importin-α7. To address this question, we assessed viral evolution in mice lacking the importin-α7 gene. We show that three mutations in particular occur with high frequency in the viral nucleoprotein (NP) protein (G102R, M105K and D375N) in a specific structural area upon in vivo adaptation. Moreover, our findings suggest that the adaptive NP mutations mediate viral escape from importin-α7 requirement likely due to the utilization of alternative interaction sites in NP beyond the classical nuclear localization signal. However, viral escape from importin-α7 by mutations in NP is, at least in part, associated with reduced viral replication highlighting the crucial contribution of importin-α7 to replicative fitness in human cells.
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Affiliation(s)
- Patricia Resa-Infante
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Jaume Bonet
- Structural Bioinformatics Lab (GRIB), Barcelona Research Park of Biomedicine (PRBB), Universitat Pompeu Fabra, Barcelona, Spain
| | - Swantje Thiele
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Malik Alawi
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany.,Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Germany
| | | | - Berfin Tuku
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Sebastian Beck
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Baldo Oliva
- Structural Bioinformatics Lab (GRIB), Barcelona Research Park of Biomedicine (PRBB), Universitat Pompeu Fabra, Barcelona, Spain
| | - Gülsah Gabriel
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany.,Institute of Virology, University of Veterinary Medicine Hannover, Hamburg, Germany
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Soh YS, Moncla LH, Eguia R, Bedford T, Bloom JD. Comprehensive mapping of adaptation of the avian influenza polymerase protein PB2 to humans. eLife 2019; 8:45079. [PMID: 31038123 PMCID: PMC6491042 DOI: 10.7554/elife.45079] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 03/31/2019] [Indexed: 12/11/2022] Open
Abstract
Viruses like influenza are infamous for their ability to adapt to new hosts. Retrospective studies of natural zoonoses and passaging in the lab have identified a modest number of host-adaptive mutations. However, it is unclear if these mutations represent all ways that influenza can adapt to a new host. Here we take a prospective approach to this question by completely mapping amino-acid mutations to the avian influenza virus polymerase protein PB2 that enhance growth in human cells. We identify numerous previously uncharacterized human-adaptive mutations. These mutations cluster on PB2’s surface, highlighting potential interfaces with host factors. Some previously uncharacterized adaptive mutations occur in avian-to-human transmission of H7N9 influenza, showing their importance for natural virus evolution. But other adaptive mutations do not occur in nature because they are inaccessible via single-nucleotide mutations. Overall, our work shows how selection at key molecular surfaces combines with evolutionary accessibility to shape viral host adaptation. Viruses copy themselves by hijacking the cells of an infected host, but this comes with some limitations. Cells from different species have different molecular machinery and so viruses often have to specialize to a narrow group of species. This specialization consists largely of fine-tuning the way that viral proteins interact with host proteins. For instance, in bird flu viruses, a protein known as PB2 does not interact well with the machinery in human cells. Because PB2 proteins form part of the viral polymerase (the structure that copies the viral genome), this prevents bird flu viruses from replicating efficiently in humans. Sometimes however, changes in the PB2 protein allow bird flu viruses to better replicate in humans, potentially leading to deadly flu pandemics. To understand exactly how this happens, researchers have previously used two approaches: examining the changes that have happened in past flu viruses, and monitoring the evolution of bird flu viruses grown in human cells in the lab. However, these approaches can only look at a small number of the many possible genetic changes to the virus. This makes it hard to anticipate the new ways that flu might adapt to human cells in the future. To overcome this problem, Soh et al. systematically created all of the single changes to the bird flu PB2, altering every element of the protein sequence one-by-one. They then tested which of the changes to PB2 helped the virus grow better in human cells. The modifications that made the viruses thrive were on the surface of the protein, suggesting that they might improve interaction with the cell machinery of the host. Some changes have been found in bird flu viruses that have recently jumped into humans in nature, although fortunately none of these viruses have yet spread widely to cause a pandemic. Many factors affect the evolution of viruses, and their ability to infect new species. Understanding which changes in proteins help these microbes adapt to new hosts is an important element that scientists could consider to assess future risks of pandemics.
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Affiliation(s)
- Yq Shirleen Soh
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Louise H Moncla
- Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, United States.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Rachel Eguia
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Trevor Bedford
- Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, United States.,Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Jesse D Bloom
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, United States.,Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, United States.,Howard Hughes Medical Institute, Seattle, United States
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47
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The PB2 Polymerase Host Adaptation Substitutions Prime Avian Indonesia Sub Clade 2.1 H5N1 Viruses for Infecting Humans. Viruses 2019; 11:v11030292. [PMID: 30909490 PMCID: PMC6480796 DOI: 10.3390/v11030292] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 12/27/2022] Open
Abstract
Significantly higher numbers of human infections with H5N1 virus have occurred in Indonesia and Egypt, compared with other affected areas, and it is speculated that there are specific viral factors for human infection with avian H5N1 viruses in these locations. We previously showed PB2-K526R is present in 80% of Indonesian H5N1 human isolates, which lack the more common PB2-E627K substitution. Testing the hypothesis that this mutation may prime avian H5N1 virus for human infection, we showed that: (1) K526R is rarely found in avian influenza viruses but was identified in H5N1 viruses 2–3 years after the virus emerged in Indonesia, coincident with the emergence of H5N1 human infections in Indonesia; (2) K526R is required for efficient replication of Indonesia H5N1 virus in mammalian cells in vitro and in vivo and reverse substitution to 526K in human isolates abolishes this ability; (3) Indonesian H5N1 virus, which contains K526R-PB2, is stable and does not further acquire E627K following replication in infected mice; and (4) virus containing K526R-PB2 shows no fitness deficit in avian species. These findings illustrate an important mechanism in which a host adaptive mutation that predisposes avian H5N1 virus towards infecting humans has arisen with the virus becoming prevalent in avian species prior to human infections occurring. A similar mechanism is observed in the Qinghai-lineage H5N1 viruses that have caused many human cases in Egypt; here, E627K predisposes towards human infections. Surveillance should focus on the detection of adaptation markers in avian strains that prime for human infection.
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Tiwari R, Jain P, Asati S, Haider T, Soni V, Pandey V. State-of-art based approaches for anticancer drug-targeting to nucleus. J Drug Deliv Sci Technol 2018. [DOI: 10.1016/j.jddst.2018.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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49
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Smith KM, Tsimbalyuk S, Edwards MR, Cross EM, Batra J, Soares da Costa TP, Aragão D, Basler CF, Forwood JK. Structural basis for importin alpha 3 specificity of W proteins in Hendra and Nipah viruses. Nat Commun 2018; 9:3703. [PMID: 30209309 PMCID: PMC6135763 DOI: 10.1038/s41467-018-05928-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 06/29/2018] [Indexed: 12/14/2022] Open
Abstract
Seven human isoforms of importin α mediate nuclear import of cargo in a tissue- and isoform-specific manner. How nuclear import adaptors differentially interact with cargo harbouring the same nuclear localisation signal (NLS) remains poorly understood, as the NLS recognition region is highly conserved. Here, we provide a structural basis for the nuclear import specificity of W proteins in Hendra and Nipah viruses. We determine the structural interfaces of these cargo bound to importin α1 and α3, identifying a 2.4-fold more extensive interface and > 50-fold higher binding affinity for importin α3. Through the design of importin α1 and α3 chimeric and mutant proteins, together with structures of cargo-free importin α1 and α3 isoforms, we establish that the molecular basis of specificity resides in the differential positioning of the armadillo repeats 7 and 8. Overall, our study provides mechanistic insights into a range of important nucleocytoplasmic transport processes reliant on isoform adaptor specificity.
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Affiliation(s)
- Kate M Smith
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Sofiya Tsimbalyuk
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Megan R Edwards
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, 30303, USA
| | - Emily M Cross
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Jyoti Batra
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, 30303, USA
| | - Tatiana P Soares da Costa
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, 3086, Australia
| | - David Aragão
- Australian Synchrotron, Australian Nuclear Science and Technology Organisation, 800 Blackburn Road, Clayton, VIC, 3168, Australia
| | - Christopher F Basler
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, 30303, USA.
| | - Jade K Forwood
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia.
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Dey V, Patankar S. Molecular basis for the lack of auto-inhibition of Plasmodium falciparum importin α. Biochem Biophys Res Commun 2018; 503:1792-1797. [DOI: 10.1016/j.bbrc.2018.07.115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 07/23/2018] [Indexed: 10/28/2022]
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