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Lin HS, Li CH, Chen LW, Wang SS, Chen LY, Hung CH, Lin CL, Chang PJ. The varicella-zoster virus ORF16 protein promotes both the nuclear transport and the protein abundance of the viral DNA polymerase subunit ORF28. Virus Res 2024; 345:199379. [PMID: 38643859 PMCID: PMC11061344 DOI: 10.1016/j.virusres.2024.199379] [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: 02/05/2024] [Revised: 04/19/2024] [Accepted: 04/19/2024] [Indexed: 04/23/2024]
Abstract
Although all herpesviruses utilize a highly conserved replication machinery to amplify their viral genomes, different members may have unique strategies to modulate the assembly of their replication components. Herein, we characterize the subcellular localization of seven essential replication proteins of varicella-zoster virus (VZV) and show that several viral replication enzymes such as the DNA polymerase subunit ORF28, when expressed alone, are localized in the cytoplasm. The nuclear import of ORF28 can be mediated by the viral DNA polymerase processivity factor ORF16. Besides, ORF16 could markedly enhance the protein abundance of ORF28. Noteworthily, an ORF16 mutant that is defective in nuclear transport still retained the ability to enhance ORF28 abundance. The low abundance of ORF28 in transfected cells was due to its rapid degradation mediated by the ubiquitin-proteasome system. We additionally reveal that radicicol, an inhibitor of the chaperone Hsp90, could disrupt the interaction between ORF16 and ORF28, thereby affecting the nuclear entry and protein abundance of ORF28. Collectively, our findings imply that the cytoplasmic retention and rapid degradation of ORF28 may be a key regulatory mechanism for VZV to prevent untimely viral DNA replication, and suggest that Hsp90 is required for the interaction between ORF16 and ORF28.
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Affiliation(s)
- Huang-Shen Lin
- Department of Internal Medicine, Division of Infectious Diseases, Chang Gung Memorial Hospital, Chiayi 61363, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Cheng-Han Li
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Lee-Wen Chen
- Department of Respiratory Care, Chang Gung University of Science and Technology, Chiayi 61363, Taiwan; Department of Pediatric Surgery, Chang Gung Memorial Hospital, Chiayi 61363, Taiwan
| | - Shie-Shan Wang
- Department of Pediatric Surgery, Chang Gung Memorial Hospital, Chiayi 61363, Taiwan; School of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Li-Yu Chen
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Chien-Hui Hung
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Chun-Liang Lin
- Department of Nephrology, Chang Gung Memorial Hospital, Chiayi 61363, Taiwan
| | - Pey-Jium Chang
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Department of Nephrology, Chang Gung Memorial Hospital, Chiayi 61363, Taiwan.
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Gao X, Xuan Y, Zhou Z, Chen C, Wen Wang D, Wen Z. Ivermectin ameliorates acute myocarditis via the inhibition of importin-mediated nuclear translocation of NF-κB/p65. Int Immunopharmacol 2024; 133:112073. [PMID: 38636372 DOI: 10.1016/j.intimp.2024.112073] [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: 12/09/2023] [Revised: 03/24/2024] [Accepted: 04/09/2024] [Indexed: 04/20/2024]
Abstract
BACKGROUND Myocarditis is an important clinical issue which lacks specific treatment by now. Ivermectin (IVM) is an inhibitor of importin α/β-mediated nuclear translocation. This study aimed to explore the therapeutic effects of IVM on acute myocarditis. METHODS Mouse models of coxsackie B3 virus (CVB3) infection-induced myocarditis and experimental autoimmune myocarditis (EAM) were established to evaluate the effects of IVM. Cardiac functions were evaluated by echocardiography and Millar catheter. Cardiac inflammatory infiltration was assessed by histological staining. Cytometric bead array and quantitative real-time PCR were used to detect the levels of pro-inflammatory cytokines. The macrophages and their M1/M2 polarization were analyzed via flow cytometry. Protein expression and binding were detected by co-immunoprecipitation, Western blotting and histological staining. The underlying mechanism was verified in vitro using CVB3-infected RAW264.7 macrophages. Cyclic polypeptide (cTN50) was synthesized to selectively inhibit the nuclear translocation of NF-κB/p65, and CVB3-infected RAW264.7 cells were treated with cTN50. RESULTS Increased expression of importin β was observed in both models. IVM treatment improved cardiac functions and reduced the cardiac inflammation associated with CVB3-myocarditis and EAM. Furthermore, the pro-inflammatory cytokine (IL-1β/IL-6/TNF-α) levels were downregulated via the inhibition of the nuclear translocation of NF-κB/p65 in macrophages. IVM and cTN50 treatment also inhibited the nuclear translocation of NF-κB/p65 and downregulated the expression of pro-inflammatory cytokines in RAW264.7 macrophages. CONCLUSIONS Ivermectin inhibits the nuclear translocation of NF-κB/p65 and the expression of major pro-inflammatory cytokines in myocarditis. The therapeutic effects of IVM on viral and non-viral myocarditis models suggest its potential application in the treatment of acute myocarditis.
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Affiliation(s)
- Xu Gao
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China
| | - Yunling Xuan
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China
| | - Zhou Zhou
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China
| | - Chen Chen
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China
| | - Dao Wen Wang
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China
| | - Zheng Wen
- Division of Cardiology, Department of Internal Medicine and Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic Disorders, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China.
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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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Cross EM, Marin O, Ariawan D, Aragão D, Cozza G, Di Iorio E, Forwood JK, Alvisi G. Structural determinants of phosphorylation-dependent nuclear transport of HCMV DNA polymerase processivity factor UL44. FEBS Lett 2024; 598:199-209. [PMID: 38158756 DOI: 10.1002/1873-3468.14797] [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: 10/30/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
Human cytomegalovirus DNA polymerase processivity factor UL44 is transported into the nucleus by importin (IMP) α/β through a classical nuclear localization signal (NLS), and this region is susceptible to cdc2-mediated phosphorylation at position T427. Whilst phosphorylation within and close to the UL44 NLS regulates nuclear transport, the details remain elusive, due to the paucity of structural information regarding the role of negatively charged cargo phosphate groups. We addressed this issue by studying the effect of UL44 T427 phosphorylation on interaction with several IMPα isoforms by biochemical and structural approaches. Phosphorylation decreased UL44/IMPα affinity 10-fold, and a comparative structural analysis of UL44 NLS phosphorylated and non-phosphorylated peptides complexed with mouse IMPα2 revealed the structural rearrangements responsible for phosphorylation-dependent inhibition of UL44 nuclear import.
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Affiliation(s)
- Emily M Cross
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, Australia
- Diamond Light Source, Didcot, UK
| | - Oriano Marin
- Department of Biomedical Sciences, University of Padova, Italy
| | - Daryl Ariawan
- Dementia Research Centre, Macquarie University, Sydney, Australia
| | | | - Giorgio Cozza
- Department of Molecular Medicine, University of Padua, Italy
| | - Enzo Di Iorio
- Department of Molecular Medicine, University of Padua, Italy
| | - Jade K Forwood
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, Australia
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5
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Athukorala A, Donnelly CM, Pavan S, Nematollahzadeh S, Djossou VA, Nath B, Helbig KJ, Di Iorio E, McSharry BP, Alvisi G, Forwood JK, Sarker S. Structural and functional characterization of siadenovirus core protein VII nuclear localization demonstrates the existence of multiple nuclear transport pathways. J Gen Virol 2024; 105. [PMID: 38261399 DOI: 10.1099/jgv.0.001928] [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] [Indexed: 01/24/2024] Open
Abstract
Adenovirus protein VII (pVII) plays a crucial role in the nuclear localization of genomic DNA following viral infection and contains nuclear localization signal (NLS) sequences for the importin (IMP)-mediated nuclear import pathway. However, functional analysis of pVII in adenoviruses to date has failed to fully determine the underlying mechanisms responsible for nuclear import of pVII. Therefore, in the present study, we extended our analysis by examining the nuclear trafficking of adenovirus pVII from a non-human species, psittacine siadenovirus F (PsSiAdV). We identified a putative classical (c)NLS at pVII residues 120-128 (120PGGFKRRRL128). Fluorescence polarization and electrophoretic mobility shift assays demonstrated direct, high-affinity interaction with both IMPα2 and IMPα3 but not IMPβ. Structural analysis of the pVII-NLS/IMPα2 complex confirmed a classical interaction, with the major binding site of IMPα occupied by K124 of pVII-NLS. Quantitative confocal laser scanning microscopy showed that PsSiAdV pVII-NLS can confer IMPα/β-dependent nuclear localization to GFP. PsSiAdV pVII also localized in the nucleus when expressed in the absence of other viral proteins. Importantly, in contrast to what has been reported for HAdV pVII, PsSiAdV pVII does not localize to the nucleolus. In addition, our study demonstrated that inhibition of the IMPα/β nuclear import pathway did not prevent PsSiAdV pVII nuclear targeting, indicating the existence of alternative pathways for nuclear localization, similar to what has been previously shown for human adenovirus pVII. Further examination of other potential NLS signals, characterization of alternative nuclear import pathways, and investigation of pVII nuclear targeting across different adenovirus species is recommended to fully elucidate the role of varying nuclear import pathways in the nuclear localization of pVII.
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Affiliation(s)
- Ajani Athukorala
- Department of Microbiology, Anatomy, Physiology, and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
| | - Camilla M Donnelly
- School of Dentistry and Medical Sciences, Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Silvia Pavan
- Department of Molecular Medicine, University of Padua, Via Gabelli 63, 35121 Padua, Italy
| | - Sepehr Nematollahzadeh
- Department of Molecular Medicine, University of Padua, Via Gabelli 63, 35121 Padua, Italy
| | | | - Babu Nath
- School of Dentistry and Medical Sciences, Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Karla J Helbig
- Department of Microbiology, Anatomy, Physiology, and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
| | - Enzo Di Iorio
- Department of Molecular Medicine, University of Padua, Via Gabelli 63, 35121 Padua, Italy
| | - Brian P McSharry
- School of Dentistry and Medical Sciences, Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Gualtiero Alvisi
- Department of Molecular Medicine, University of Padua, Via Gabelli 63, 35121 Padua, Italy
| | - Jade K Forwood
- School of Dentistry and Medical Sciences, Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Subir Sarker
- Department of Microbiology, Anatomy, Physiology, and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
- Biomedical Sciences & Molecular Biology, College of Public Health Medical, and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia
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Bravo A, Fernández-García L, Ibarra-Karmy R, Mardones GA, Mercado L, Bustos FJ, Gifford RJ, Arriagada G. Antiviral Activity of an Endogenous Parvoviral Element. Viruses 2023; 15:1420. [PMID: 37515112 PMCID: PMC10384997 DOI: 10.3390/v15071420] [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: 06/07/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Endogenous viral elements (EVEs) are genomic DNA sequences derived from viruses. Some EVEs have open reading frames (ORFs) that can express proteins with physiological roles in their host. Furthermore, some EVEs exhibit a protective role against exogenous viral infection in their host. Endogenous parvoviral elements (EPVs) are highly represented in mammalian genomes, and although some of them contain ORFs, their function is unknown. We have shown that the locus EPV-Dependo.43-ODegus, an EPV with an intact ORF, is transcribed in Octodon degus (degu). Here we examine the antiviral activity of the protein encoded in this EPV, named DeRep. DeRep was produced in bacteria and used to generate antibodies that recognize DeRep in western blots of degu tissue. To test if DeRep could protect against exogenous parvovirus, we challenged cells with the minute virus of mice (MVM), a model autonomous parvovirus. We observed that MVM protein expression, DNA damage induced by replication, viral DNA, and cytopathic effects are reduced when DeRep is expressed in cells. The results of this study demonstrate that DeRep is expressed in degu and can inhibit parvovirus replication. This is the first time that an EPV has been shown to have antiviral activity against an exogenous virus.
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Affiliation(s)
- Angelica Bravo
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
| | - Leandro Fernández-García
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
| | - Rodrigo Ibarra-Karmy
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
| | - Gonzalo A Mardones
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia 5110466, Chile
| | - Luis Mercado
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso 2373223, Chile
| | - Fernando J Bustos
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
| | - Robert J Gifford
- Centre for Virus Research, MRC-University of Glasgow, 464 Bearsden Rd, Bearsden, Glasgow G61 1QH, UK
| | - Gloria Arriagada
- Instituto de Ciencias Biomedicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370071, Chile
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Han L, Song S, Feng H, Ma J, Wei W, Si F. A roadmap for developing Venezuelan equine encephalitis virus (VEEV) vaccines: Lessons from the past, strategies for the future. Int J Biol Macromol 2023:125514. [PMID: 37353130 DOI: 10.1016/j.ijbiomac.2023.125514] [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: 04/11/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023]
Abstract
Venezuelan equine encephalitis (VEE) is a zoonotic infectious disease caused by the Venezuelan equine encephalitis virus (VEEV), which can lead to severe central nervous system infections in both humans and animals. At present, the medical community does not possess a viable means of addressing VEE, rendering the prevention of the virus a matter of paramount importance. Regarding the prevention and control of VEEV, the implementation of a vaccination program has been recognized as the most efficient strategy. Nevertheless, there are currently no licensed vaccines or drugs available for human use against VEEV. This imperative has led to a surge of interest in vaccine research, with VEEV being a prime focus for researchers in the field. In this paper, we initially present a comprehensive overview of the current taxonomic classification of VEEV and the cellular infection mechanism of the virus. Subsequently, we provide a detailed introduction of the prominent VEEV vaccine types presently available, including inactivated vaccines, live attenuated vaccines, genetic, and virus-like particle vaccines. Moreover, we emphasize the challenges that current VEEV vaccine development faces and suggest urgent measures that must be taken to overcome these obstacles. Notably, based on our latest research, we propose the feasibility of incorporation codon usage bias strategies to create the novel VEEV vaccine. Finally, we prose several areas that future VEEV vaccine development should focus on. Our objective is to encourage collaboration between the medical and veterinary communities, expedite the translation of existing vaccines from laboratory to clinical applications, while also preparing for future outbreaks of new VEEV variants.
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Affiliation(s)
- Lulu Han
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai 201106, China; Huaihe Hospital of Henan University, Clinical Medical College of Henan University, Kai Feng 475000, China
| | - Shuai Song
- Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Key Laboratory of Livestock Disease Prevention of Guangdong Province, Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province, Ministry of Agriculture and Rural Affairs, Guangzhou 510640, PR China
| | - Huilin Feng
- Kaifeng Key Laboratory of Infection and Biological Safety, School of Basic Medical Sciences of Henan University, Kai Feng 475000, China
| | - Jing Ma
- Huaihe Hospital of Henan University, Clinical Medical College of Henan University, Kai Feng 475000, China
| | - Wenqiang Wei
- Kaifeng Key Laboratory of Infection and Biological Safety, School of Basic Medical Sciences of Henan University, Kai Feng 475000, China.
| | - Fusheng Si
- Institute of Animal Science and Veterinary Medicine, Shanghai Academy of Agricultural Sciences, Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai Engineering Research Center of Breeding Pig, Shanghai 201106, China.
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8
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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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