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Mohamadynejad P, Moghanibashi M, Bagheri K. Identification of novel nuclear pore complex associated proteins in esophageal carcinoma by an integrated bioinformatics analysis. J Biomol Struct Dyn 2024; 42:7221-7232. [PMID: 37504972 DOI: 10.1080/07391102.2023.2240414] [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: 01/29/2023] [Accepted: 07/15/2023] [Indexed: 07/29/2023]
Abstract
Nucleoporins (NUPs) are components of the nuclear pore complex (NPC) that participate in the nucleocytoplasmic transport of macromolecules as well as in many essential processes that may be led to carcinogenesis. We selected three expression profile microarray datasets from GEO and as well as TCGA data to identify differentially expressed NUPs genes in esophageal carcinoma. Our findings indicated that NUP133, NUP37, NUP43, NUP50, GLE1 and NDC1 are overexpressed in esophageal carcinoma, among which NUP50 and GLE1genes are reported for the first time in esophageal carcinoma. All identified NUPs were also associated with distant metastasis.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Parisa Mohamadynejad
- Department of Biology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
| | - Mehdi Moghanibashi
- Department of Genetics, Faculty of Medicine, Kazerun Branch, Islamic Azad University, Kazerun, Iran
| | - Kambiz Bagheri
- Department of Immunology, Faculty of Medicine, Kazerun Branch, Islamic Azad University, Kazerun, Iran
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2
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Chang YK, Lin YJ, Cheng CY, Tsai PC, Wang CY, Nielsen BL, Liu HJ. Nucleocytoplasmic shuttling of BEFV M protein-modulated by lamin A/C and chromosome maintenance region 1 through a transcription-, carrier- and energy-dependent pathway. Vet Microbiol 2024; 291:110026. [PMID: 38364467 DOI: 10.1016/j.vetmic.2024.110026] [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: 12/12/2023] [Revised: 01/30/2024] [Accepted: 02/07/2024] [Indexed: 02/18/2024]
Abstract
This study demonstrates for the first time that the matrix (M) protein of BEFV is a nuclear targeting protein that shuttles between the nucleus and the cytoplasm in a transcription-, carrier-, and energy-dependent manner. Experiments performed in both intact cells and digitonin-permeabilized cells revealed that M protein targets the nucleolus and requires carrier, cytosolic factors or energy input. By employing sequence and mutagenesis analyses, we have determined both nuclear localization signal (NLS) 6KKGKSK11 and nuclear export signal (NES) 98LIITSYL TI106 of M protein that are important for the nucleocytoplasmic shuttling of M protein. Furthermore, we found that both lamin A/C and chromosome maintenance region 1 (CRM-1) proteins could be coimmunoprecipitated and colocalized with the BEFV M protein. Knockdown of lamin A/C by shRNA and inhibition of CRM-1 by leptomycin B significantly reduced virus yield. Collectively, this study provides novel insights into nucleocytoplasmic shuttling of the BEFV M protein modulated by lamin A/C and CRM-1 and by a transcription- and carrier- and energy-dependent pathway.
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Affiliation(s)
- Yu-Kang Chang
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan, ROC; Depertment of Post-Baccalaureate Medicine, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Yi-Jyum Lin
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Ching-Yuan Cheng
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Pei-Chien Tsai
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Chi-Young Wang
- Department of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan, ROC; The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Brent L Nielsen
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, USA
| | - Hung-Jen Liu
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, ROC; Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, ROC; The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung, Taiwan, ROC; Ph.D Program in Translational Medicine, National Chung Hsing University, Taichung, Taiwan, ROC; Rong Hsing Research Center for Translational Medicine, National Chung Hsing, Taiwan, ROC.
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3
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Kapinos LE, Kalita J, Kassianidou E, Rencurel C, Lim RYH. Mechanism of exportin retention in the cell nucleus. J Cell Biol 2024; 223:e202306094. [PMID: 38241019 PMCID: PMC10798875 DOI: 10.1083/jcb.202306094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 11/06/2023] [Accepted: 12/07/2023] [Indexed: 01/22/2024] Open
Abstract
Exportin receptors are concentrated in the nucleus to transport essential cargoes out of it. A mislocalization of exportins to the cytoplasm is linked to disease. Hence, it is important to understand how their containment within the nucleus is regulated. Here, we have studied the nuclear efflux of exportin2 (cellular apoptosis susceptibility protein or CAS) that delivers karyopherinα (Kapα or importinα), the cargo adaptor for karyopherinβ1 (Kapβ1 or importinβ1), to the cytoplasm in a Ran guanosine triphosphate (RanGTP)-mediated manner. We show that the N-terminus of CAS attenuates the interaction of RanGTPase activating protein 1 (RanGAP1) with RanGTP to slow GTP hydrolysis, which suppresses CAS nuclear exit at nuclear pore complexes (NPCs). Strikingly, a single phosphomimetic mutation (T18D) at the CAS N-terminus is sufficient to abolish its nuclear retention and coincides with metastatic cellular behavior. Furthermore, downregulating Kapβ1 disrupts CAS nuclear retention, which highlights the balance between their respective functions that is essential for maintaining the Kapα transport cycle. Therefore, NPCs play a functional role in selectively partitioning exportins in the cell nucleus.
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Affiliation(s)
- Larisa E. Kapinos
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
| | - Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
| | - Elena Kassianidou
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
| | - Chantal Rencurel
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
| | - Roderick Y. H. Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel Switzerland, Basel, Switzerland
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4
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Wang J, Hsu Y, Lee Y, Lin N. Importin α2 participates in RNA interference against bamboo mosaic virus accumulation in Nicotiana benthamiana via NbAGO10a-mediated small RNA clearance. MOLECULAR PLANT PATHOLOGY 2024; 25:e13422. [PMID: 38279848 PMCID: PMC10799208 DOI: 10.1111/mpp.13422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/29/2024]
Abstract
Karyopherins, the nucleocytoplasmic transporters, participate in multiple RNA silencing stages by transporting associated proteins into the nucleus. Importin α is a member of karyopherins and has been reported to facilitate virus infection via nuclear import of viral proteins. Unlike other RNA viruses, silencing of importin α2 (α2i) by virus-induced gene silencing (VIGS) boosted the titre of bamboo mosaic virus (BaMV) in protoplasts, and inoculated and systemic leaves of Nicotiana benthamiana. The enhanced BaMV accumulation in importin α2i plants was linked to reduced levels of RDR6-dependent secondary virus-derived small-interfering RNAs (vsiRNAs). Small RNA-seq revealed importin α2 silencing did not affect the abundance of siRNAs derived from host mRNAs but significantly reduced the 21 and 22 nucleotide vsiRNAs in BaMV-infected plants. Deletion of BaMV TGBp1, an RNA silencing suppressor, compromised importin α2i-mediated BaMV enhancement. Moreover, silencing of importin α2 upregulated NbAGO10a, a proviral protein recruited by TGBp1 for BaMV vsiRNAs clearance, but hindered the nuclear import of NbAGO10a. Taken together, these results indicate that importin α2 acts as a negative regulator of BaMV invasion by controlling the expression and nucleocytoplasmic shuttling of NbAGO10a, which removes vsiRNAs via the TGBp1-NbAGO10a-SDN1 pathway. Our findings reveal the hidden antiviral mechanism of importin α2 in countering BaMV infection in N. benthamiana.
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Affiliation(s)
- Jiun‐Da Wang
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan
| | - Yau‐Heiu Hsu
- Graduate Institute of BiotechnologyNational Chung Hsing UniversityTaichungTaiwan
| | - Yun‐Shien Lee
- Department of BiotechnologyMing Chuan UniversityTaipeiTaiwan
| | - Na‐Sheng Lin
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan
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Moens U, Passerini S, Falquet M, Sveinbjørnsson B, Pietropaolo V. Phosphorylation of Human Polyomavirus Large and Small T Antigens: An Ignored Research Field. Viruses 2023; 15:2235. [PMID: 38005912 PMCID: PMC10674619 DOI: 10.3390/v15112235] [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: 10/17/2023] [Revised: 11/02/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023] Open
Abstract
Protein phosphorylation and dephosphorylation are the most common post-translational modifications mediated by protein kinases and protein phosphatases, respectively. These reversible processes can modulate the function of the target protein, such as its activity, subcellular localization, stability, and interaction with other proteins. Phosphorylation of viral proteins plays an important role in the life cycle of a virus. In this review, we highlight biological implications of the phosphorylation of the monkey polyomavirus SV40 large T and small t antigens, summarize our current knowledge of the phosphorylation of these proteins of human polyomaviruses, and conclude with gaps in the knowledge and a proposal for future research directions.
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Affiliation(s)
- Ugo Moens
- Department of Medical Biology, Faculty of Health Sciences, University of Tromsø—The Arctic University of Norway, 9037 Tromsø, Norway; (M.F.); (B.S.)
| | - Sara Passerini
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy;
| | - Mar Falquet
- Department of Medical Biology, Faculty of Health Sciences, University of Tromsø—The Arctic University of Norway, 9037 Tromsø, Norway; (M.F.); (B.S.)
| | - Baldur Sveinbjørnsson
- Department of Medical Biology, Faculty of Health Sciences, University of Tromsø—The Arctic University of Norway, 9037 Tromsø, Norway; (M.F.); (B.S.)
| | - Valeria Pietropaolo
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy;
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Ogorek TJ, Golden JE. Advances in the Development of Small Molecule Antivirals against Equine Encephalitic Viruses. Viruses 2023; 15:413. [PMID: 36851628 PMCID: PMC9958955 DOI: 10.3390/v15020413] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/29/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
Venezuelan, western, and eastern equine encephalitic alphaviruses (VEEV, WEEV, and EEEV, respectively) are arboviruses that are highly pathogenic to equines and cause significant harm to infected humans. Currently, human alphavirus infection and the resulting diseases caused by them are unmitigated due to the absence of approved vaccines or therapeutics for general use. These circumstances, combined with the unpredictability of outbreaks-as exemplified by a 2019 EEE surge in the United States that claimed 19 patient lives-emphasize the risks posed by these viruses, especially for aerosolized VEEV and EEEV which are potential biothreats. Herein, small molecule inhibitors of VEEV, WEEV, and EEEV are reviewed that have been identified or advanced in the last five years since a comprehensive review was last performed. We organize structures according to host- versus virus-targeted mechanisms, highlight cellular and animal data that are milestones in the development pipeline, and provide a perspective on key considerations for the progression of compounds at early and later stages of advancement.
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Affiliation(s)
- Tyler J. Ogorek
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jennifer E. Golden
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA
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Kehn-Hall K, Bradfute SB. Understanding host responses to equine encephalitis virus infection: implications for therapeutic development. Expert Rev Anti Infect Ther 2022; 20:1551-1566. [PMID: 36305549 DOI: 10.1080/14787210.2022.2141224] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Venezuelan, eastern, and western equine encephalitis viruses (VEEV, EEEV, and WEEV) are mosquito-borne New World alphaviruses that cause encephalitis in equids and humans. These viruses can cause severe disease and death, as well as long-term severe neurological symptoms in survivors. Despite the pathogenesis and weaponization of these viruses, there are no approved therapeutics for treating infection. AREAS COVERED In this review, we describe the molecular pathogenesis of these viruses, discuss host-pathogen interactions needed for viral replication, and highlight new avenues for drug development with a focus on host-targeted approaches. EXPERT OPINION Current approaches have yielded some promising therapeutics, but additional emphasis should be placed on advanced development of existing small molecules and pursuit of pan-encephalitic alphavirus drugs. More research should be conducted on EEEV and WEEV, given their high lethality rates.
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Affiliation(s)
- Kylene Kehn-Hall
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA.,Center for Emerging, Zoonotic, and Arthropod-borne Pathogens, Virginia Tech, Blacksburg, VA, USA
| | - Steven B Bradfute
- Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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Walunj SB, Wang C, Wagstaff KM, Patankar S, Jans DA. Conservation of Importin α Function in Apicomplexans: Ivermectin and GW5074 Target Plasmodium falciparum Importin α and Inhibit Parasite Growth in Culture. Int J Mol Sci 2022; 23:ijms232213899. [PMID: 36430384 PMCID: PMC9695642 DOI: 10.3390/ijms232213899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/03/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
Signal-dependent transport into and out of the nucleus mediated by members of the importin (IMP) superfamily of nuclear transporters is critical to the eukaryotic function and a point of therapeutic intervention with the potential to limit disease progression and pathogenic outcomes. Although the apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii both retain unique IMPα genes that are essential, a detailed analysis of their properties has not been performed. As a first step to validate apicomplexan IMPα as a target, we set out to compare the properties of P. falciparum and T. gondii IMPα (PfIMPα and TgIMPα, respectively) to those of mammalian IMPα, as exemplified by Mus musculus IMPα (MmIMPα). Close similarities were evident, with all three showing high-affinity binding to modular nuclear localisation signals (NLSs) from apicomplexans as well as Simian virus SV40 large tumour antigen (T-ag). PfIMPα and TgIMPα were also capable of binding to mammalian IMPβ1 (MmIMPβ1) with high affinity; strikingly, NLS binding by PfIMPα and TgIMPα could be inhibited by the mammalian IMPα targeting small molecules ivermectin and GW5074 through direct binding to PfIMPα and TgIMPα to perturb the α-helical structure. Importantly, GW5074 could be shown for the first time to resemble ivermectin in being able to limit growth of P. falciparum. The results confirm apicomplexan IMPα as a viable target for the development of therapeutics, with agents targeting it worthy of further consideration as an antimalarial.
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Affiliation(s)
- Sujata B. Walunj
- Molecular Parasitology Lab., Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
- Nuclear Signalling Lab., Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Monash, VIC 3800, Australia
| | - Chunxiao Wang
- Nuclear Signalling Lab., Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Monash, VIC 3800, Australia
| | - Kylie M. Wagstaff
- Nuclear Signalling Lab., Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Monash, VIC 3800, Australia
| | - Swati Patankar
- Molecular Parasitology Lab., Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - David A. Jans
- Nuclear Signalling Lab., Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Monash, VIC 3800, Australia
- Correspondence:
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Abstract
Ebola virus (EBOV) VP30 regulates viral genome transcription and replication by switching its phosphorylation status. However, the importance of VP30 phosphorylation and dephosphorylation in other viral replication processes such as nucleocapsid and virion assembly is unclear. Interestingly, VP30 is predominantly dephosphorylated by cellular phosphatases in viral inclusions, while it is phosphorylated in the released virions. Thus, uncertainties regarding how VP30 phosphorylation in nucleocapsids is achieved and whether VP30 phosphorylation provides any advantages in later steps in viral replication have arisen. In the present study, to characterize the roles of VP30 phosphorylation in nucleocapsid formation, we used electron microscopic analyses and live cell imaging systems. We identified VP30 localized to the surface of protrusions surrounding nucleoprotein (NP)-forming helical structures in the nucleocapsid, suggesting the involvement in assembly and transport of nucleocapsids. Interestingly, VP30 phosphorylation facilitated its association with nucleocapsid-like structures (NCLSs). On the contrary, VP30 phosphorylation does not influence the transport characteristics and NCLS number leaving from and coming back into viral inclusions, indicating that the phosphorylation status of VP30 is not a prerequisite for NCLS departure. Moreover, the phosphorylation status of VP30 did not cause major differences in nucleocapsid transport in authentic EBOV-infected cells. In the following budding step, the association of VP30 and its phosphorylation status did not influence the budding efficiency of virus-like particles. Taken together, it is plausible that EBOV may utilize the phosphorylation of VP30 for its selective association with nucleocapsids, without affecting nucleocapsid transport and virion budding processes. IMPORTANCE Ebola virus (EBOV) causes severe fevers with unusually high case fatality rates. The nucleocapsid provides the template for viral genome transcription and replication. Thus, understanding the regulatory mechanism behind its formation is important for the development of novel therapeutic approaches. Previously, we established a live-cell imaging system based on the ectopic expression of viral fluorescent fusion proteins, allowing the visualization and characterization of intracytoplasmic transport of nucleocapsid-like structures. EBOV VP30 is an essential transcriptional factor for viral genome synthesis, and, although its role in viral genome transcription and replication is well understood, the functional importance of VP30 phosphorylation in assembly of nucleocapsids is still unclear. Our work determines the localization of VP30 at the surface of ruffled nucleocapsids, which differs from the localization of polymerase in EBOV-infected cells. This study sheds light on the novel role of VP30 phosphorylation in nucleocapsid assembly, which is an important prerequisite for virion formation.
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Ghildyal R, Teng MN, Tran KC, Mills J, Casarotto MG, Bardin PG, Jans DA. Nuclear Transport of Respiratory Syncytial Virus Matrix Protein Is Regulated by Dual Phosphorylation Sites. Int J Mol Sci 2022; 23:ijms23147976. [PMID: 35887322 PMCID: PMC9317576 DOI: 10.3390/ijms23147976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/02/2022] [Accepted: 07/06/2022] [Indexed: 02/04/2023] Open
Abstract
Respiratory syncytial virus (RSV) is a major cause of respiratory infections in infants and the elderly. Although the RSV matrix (M) protein has key roles in the nucleus early in infection, and in the cytoplasm later, the molecular basis of switching between the nuclear and cytoplasmic compartments is not known. Here, we show that protein kinase CK2 can regulate M nucleocytoplasmic distribution, whereby inhibition of CK2 using the specific inhibitor 4,5,6,7-tetrabromobenzo-triazole (TBB) increases M nuclear accumulation in infected cells as well as when ectopically expressed in transfected cells. We use truncation/mutagenic analysis for the first time to show that serine (S) 95 and threonine (T) 205 are key CK2 sites that regulate M nuclear localization. Dual alanine (A)-substitution to prevent phosphorylation abolished TBB- enhancement of nuclear accumulation, while aspartic acid (D) substitution to mimic phosphorylation at S95 increased nuclear accumulation. D95 also induced cytoplasmic aggregate formation, implying that a negative charge at S95 may modulate M oligomerization. A95/205 substitution in recombinant RSV resulted in reduced virus production compared with wild type, with D95/205 substitution resulting in an even greater level of attenuation. Our data support a model where unphosphorylated M is imported into the nucleus, followed by phosphorylation of T205 and S95 later in infection to facilitate nuclear export and cytoplasmic retention of M, respectively, as well as oligomerization/virus budding. In the absence of widely available, efficacious treatments to protect against RSV, the results raise the possibility of antiviral strategies targeted at CK2.
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Affiliation(s)
- Reena Ghildyal
- Centre for Research in Therapeutic Solutions, Faculty of Science and Technology, University of Canberra, Canberra 2617, Australia
- Correspondence: ; Tel.: +612-6201-5755
| | - Michael N. Teng
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; (M.N.T.); (K.C.T.)
| | - Kim C. Tran
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; (M.N.T.); (K.C.T.)
| | - John Mills
- Faculty of Medicine, Monash University, Burnet Institute for Medical Research, The Alfred Hospital Department of Infectious Diseases, Melbourne 3004, Australia;
| | - Marco G. Casarotto
- Research School of Biology, Australian National University, Canberra 2601, Australia;
| | - Philip G. Bardin
- Monash Lung & Sleep and Hudson Institute, Monash University, Melbourne 3181, Australia;
| | - David A. Jans
- Nuclear Signalling Lab., Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3181, Australia;
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11
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Molecular Basis of Functional Effects of Phosphorylation of the C-Terminal Domain of the Rabies Virus P Protein. J Virol 2022; 96:e0011122. [DOI: 10.1128/jvi.00111-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Rabies virus P protein is a multifunctional protein with critical roles in replication and manipulation of host-cell processes, including subversion of immunity. This functional diversity involves interactions of several P protein isoforms with the cell nucleus and microtubules.
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12
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High-Throughput Screening to Identify Inhibitors of Plasmodium falciparum Importin α. Cells 2022; 11:cells11071201. [PMID: 35406765 PMCID: PMC8997399 DOI: 10.3390/cells11071201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 03/25/2022] [Accepted: 03/29/2022] [Indexed: 11/16/2022] Open
Abstract
The global burden of malaria and toxoplasmosis has been limited by the use of efficacious anti-parasitic agents, however, emerging resistance in Plasmodium species and Toxoplasma gondii threatens disease control worldwide, implying that new agents/therapeutic targets are urgently needed. Nuclear localization signal (NLS)-dependent transport into the nucleus, mediated by members of the importin (IMP) superfamily of nuclear transporters, has shown potential as a target for intervention to limit viral infection. Here, we show for the first time that IMPα from P. falciparum and T. gondii have promise as targets for small molecule inhibitors. We use high-throughput screening to identify agents able to inhibit P. falciparum IMPα binding to a P. falciparum NLS, identifying a number of compounds that inhibit binding in the µM-nM range, through direct binding to P. falciparum IMPα, as shown in thermostability assays. Of these, BAY 11-7085 is shown to be a specific inhibitor of P. falciparum IMPα-NLS recognition. Importantly, a number of the inhibitors limited growth by both P. falciparum and T. gondii. The results strengthen the hypothesis that apicomplexan IMPα proteins have potential as therapeutic targets to aid in identifying novel agents for two important, yet neglected, parasitic diseases.
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Dicks LMT, Deane SM, Grobbelaar MJ. Could the COVID-19-Driven Increased Use of Ivermectin Lead to Incidents of Imbalanced Gut Microbiota and Dysbiosis? Probiotics Antimicrob Proteins 2022; 14:217-223. [PMID: 35218001 PMCID: PMC8881049 DOI: 10.1007/s12602-022-09925-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2022] [Indexed: 12/20/2022]
Abstract
The microfilaricidal anthelmintic drug ivermectin (IVM) has been used since 1988 for treatment of parasitic infections in animals and humans. The discovery of IVM’s ability to inactivate the eukaryotic importin α/β1 heterodimer (IMPα/β1), used by some viruses to enter the nucleus of susceptible hosts, led to the suggestion of using the drug to combat SARS-CoV-2 infection. Since IVM has antibacterial properties, prolonged use may affect commensal gut microbiota. In this review, we investigate the antimicrobial properties of IVM, possible mode of activity, and the concern that treatment of individuals diagnosed with COVID-19 may lead to dysbiosis.
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Affiliation(s)
- Leon M T Dicks
- Department of Microbiology, Stellenbosch University, Stellenbosch, 7600, South Africa.
| | - Shelly M Deane
- Department of Microbiology, Stellenbosch University, Stellenbosch, 7600, South Africa
| | - Matthew J Grobbelaar
- Department of Microbiology, Stellenbosch University, Stellenbosch, 7600, South Africa
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14
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Zaidi AK, Dehgani-Mobaraki P. The mechanisms of action of ivermectin against SARS-CoV-2-an extensive review. J Antibiot (Tokyo) 2022; 75:60-71. [PMID: 34931048 PMCID: PMC8688140 DOI: 10.1038/s41429-021-00491-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/14/2022]
Abstract
Considering the urgency of the ongoing COVID-19 pandemic, detection of new mutant strains and potential re-emergence of novel coronaviruses, repurposing of drugs such as ivermectin could be worthy of attention. This review article aims to discuss the probable mechanisms of action of ivermectin against SARS-CoV-2 by summarizing the available literature over the years. A schematic of the key cellular and biomolecular interactions between ivermectin, host cell, and SARS-CoV-2 in COVID-19 pathogenesis and prevention of complications has been proposed.
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Affiliation(s)
- Asiya Kamber Zaidi
- Association "Naso Sano" Onlus, Umbria Regional Registry of Volunteer Activities, Corciano, Italy.
| | - Puya Dehgani-Mobaraki
- Association "Naso Sano" Onlus, Umbria Regional Registry of Volunteer Activities, Corciano, Italy
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15
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Lee A, Bogoyevitch MA, Jans DA. Bimolecular Fluorescence Complementation: Quantitative Analysis of In Cell Interaction of Nuclear Transporter Importin α with Cargo Proteins. Methods Mol Biol 2022; 2502:215-233. [PMID: 35412241 DOI: 10.1007/978-1-0716-2337-4_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Bimolecular fluorescence complementation utilizes the ability of two complementary nonfluorescent fragments to reconstitute and emit fluorescence when brought together through specific interaction of attached protein fragments of interest. It has been used in several different contexts to study protein-protein interaction. Here we apply the method for the first time to study interaction of the nuclear transporter importin α and its cargoes in a cellular context. By using image analysis to quantify the extent of nuclear complexation, it is possible to gain insight into the strength of interaction in cells.
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Affiliation(s)
- Alexander Lee
- Nuclear Signalling Laboratory, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia
| | - Marie A Bogoyevitch
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia
| | - David A Jans
- Nuclear Signalling Laboratory, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, Australia.
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16
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Kalita J, Kapinos LE, Lim RYH. On the asymmetric partitioning of nucleocytoplasmic transport - recent insights and open questions. J Cell Sci 2021; 134:239102. [PMID: 33912945 DOI: 10.1242/jcs.240382] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Macromolecular cargoes are asymmetrically partitioned in the nucleus or cytoplasm by nucleocytoplasmic transport (NCT). At the center of this activity lies the nuclear pore complex (NPC), through which soluble factors circulate to orchestrate NCT. These include cargo-carrying importin and exportin receptors from the β-karyopherin (Kapβ) family and the small GTPase Ran, which switches between guanosine triphosphate (GTP)- and guanosine diphosphate (GDP)-bound forms to regulate cargo delivery and compartmentalization. Ongoing efforts have shed considerable light on how these soluble factors traverse the NPC permeability barrier to sustain NCT. However, this does not explain how importins and exportins are partitioned in the cytoplasm and nucleus, respectively, nor how a steep RanGTP-RanGDP gradient is maintained across the nuclear envelope. In this Review, we peel away the multiple layers of control that regulate NCT and juxtapose unresolved features against known aspects of NPC function. Finally, we discuss how NPCs might function synergistically with Kapβs, cargoes and Ran to establish the asymmetry of NCT.
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Affiliation(s)
- Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Larisa E Kapinos
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
| | - Roderick Y H Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Basel CH4056, Switzerland
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17
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Nuclear localisation of West Nile virus NS5 protein modulates host gene expression. Virology 2021; 559:131-144. [PMID: 33866234 DOI: 10.1016/j.virol.2021.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 01/01/2023]
Abstract
The involvement of the nucleus during flavivirus infection has been observed in only a small number of cases and can be limited to primarily two viral proteins; the structural protein C and the RNA polymerase NS5. Previously we observed that by blocking nuclear transport, WNV strain Kunjin (WNVKUN) replication is severely affected and through mutation of the identified NLS in WNVKUN NS5 protein. In this study, we interrogated the potential nuclear functions of WNVKUN NS5 has on the host transcriptome, by means of RNA sequencing (RNAseq). In a direct comparison between wild type and mutant NS5, it can also be determined that the nuclear translocation of NS5 results in a significant down-regulation of host genes involved in the innate immune response. When compared to published RNAseq data from WNV infection, many of these genes were overlapping indicting the role of NS5 induced transcription during infection.
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18
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Wehbe Z, Wehbe M, Iratni R, Pintus G, Zaraket H, Yassine HM, Eid AH. Repurposing Ivermectin for COVID-19: Molecular Aspects and Therapeutic Possibilities. Front Immunol 2021; 12:663586. [PMID: 33859652 PMCID: PMC8043070 DOI: 10.3389/fimmu.2021.663586] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/15/2021] [Indexed: 12/15/2022] Open
Abstract
As of January 2021, SARS-CoV-2 has killed over 2 million individuals across the world. As such, there is an urgent need for vaccines and therapeutics to reduce the burden of COVID-19. Several vaccines, including mRNA, vector-based vaccines, and inactivated vaccines, have been approved for emergency use in various countries. However, the slow roll-out of vaccines and insufficient global supply remains a challenge to turn the tide of the pandemic. Moreover, vaccines are important tools for preventing the disease but therapeutic tools to treat patients are also needed. As such, since the beginning of the pandemic, repurposed FDA-approved drugs have been sought as potential therapeutic options for COVID-19 due to their known safety profiles and potential anti-viral effects. One of these drugs is ivermectin (IVM), an antiparasitic drug created in the 1970s. IVM later exerted antiviral activity against various viruses including SARS-CoV-2. In this review, we delineate the story of how this antiparasitic drug was eventually identified as a potential treatment option for COVID-19. We review SARS-CoV-2 lifecycle, the role of the nucleocapsid protein, the turning points in past research that provided initial 'hints' for IVM's antiviral activity and its molecular mechanism of action- and finally, we culminate with the current clinical findings.
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Affiliation(s)
- Zena Wehbe
- Department of Biology, Faculty of Arts and Sciences, American University of Beirut, Beirut, Lebanon
| | - Maya Wehbe
- Department of Internal Medicine, Basingstoke & North Hampshire Hospital, Basingstoke, United Kingdom
| | - Rabah Iratni
- Department of Biology, College of Science, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Gianfranco Pintus
- Department of Medical Laboratory Sciences, College of Health Sciences, and Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Hassan Zaraket
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Center for Infectious Disease Research (CIDR), Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hadi M. Yassine
- Biomedical Research Center, Q.U. Health, Qatar University, Doha, Qatar
| | - Ali H. Eid
- Department of Basic Medical Sciences, College of Medicine, Q.U. Health. Qatar University, Doha, Qatar
- Biomedical and Pharmaceutical Research Unit, Q.U. Health, Qatar University, Doha, Qatar
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19
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Martin AJ, Jans DA. Antivirals that target the host IMPα/β1-virus interface. Biochem Soc Trans 2021; 49:281-295. [PMID: 33439253 PMCID: PMC7925013 DOI: 10.1042/bst20200568] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 12/22/2022]
Abstract
Although transport into the nucleus mediated by the importin (IMP) α/β1-heterodimer is central to viral infection, small molecule inhibitors of IMPα/β1-dependent nuclear import have only been described and shown to have antiviral activity in the last decade. Their robust antiviral activity is due to the strong reliance of many different viruses, including RNA viruses such as human immunodeficiency virus-1 (HIV-1), dengue (DENV), and Zika (ZIKV), on the IMPα/β1-virus interface. High-throughput compound screens have identified many agents that specifically target this interface. Of these, agents targeting IMPα/β1 directly include the FDA-approved macrocyclic lactone ivermectin, which has documented broad-spectrum activity against a whole range of viruses, including HIV-1, DENV1-4, ZIKV, West Nile virus (WNV), Venezuelan equine encephalitis virus, chikungunya, and most recently, SARS-CoV-2 (COVID-19). Ivermectin has thus far been tested in Phase III human clinical trials for DENV, while there are currently close to 80 trials in progress worldwide for SARS-CoV-2; preliminary results for randomised clinical trials (RCTs) as well as observational/retrospective studies are consistent with ivermectin affording clinical benefit. Agents that target the viral component of the IMPα/β1-virus interface include N-(4-hydroxyphenyl) retinamide (4-HPR), which specifically targets DENV/ZIKV/WNV non-structural protein 5 (NS5). 4-HPR has been shown to be a potent inhibitor of infection by DENV1-4, including in an antibody-dependent enhanced animal challenge model, as well as ZIKV, with Phase II clinical challenge trials planned. The results from rigorous RCTs will help determine the therapeutic potential of the IMPα/β1-virus interface as a target for antiviral development.
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Affiliation(s)
- Alexander J. Martin
- Nuclear Signaling Lab., Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - David A. Jans
- Nuclear Signaling Lab., Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
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20
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Paci G, Caria J, Lemke EA. Cargo transport through the nuclear pore complex at a glance. J Cell Sci 2021; 134:237315. [PMID: 33495357 DOI: 10.1242/jcs.247874] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bidirectional transport of macromolecules across the nuclear envelope is a hallmark of eukaryotic cells, in which the genetic material is compartmentalized inside the nucleus. The nuclear pore complex (NPC) is the major gateway to the nucleus and it regulates nucleocytoplasmic transport, which is key to processes including transcriptional regulation and cell cycle control. Accordingly, components of the nuclear transport machinery are often found to be dysregulated or hijacked in diseases. In this Cell Science at a Glance article and accompanying poster, we provide an overview of our current understanding of cargo transport through the NPC, from the basic transport signals and machinery to more emerging aspects, all from a 'cargo perspective'. Among these, we discuss the transport of large cargoes (>15 nm), as well as the roles of different cargo properties to nuclear transport, from size and number of bound nuclear transport receptors (NTRs), to surface and mechanical properties.
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Affiliation(s)
- Giulia Paci
- Biocentre, Johannes Gutenberg-University Mainz, Hans-Dieter-Hüsch-Weg 15, 555128 Mainz, Germany.,Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.,European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Joana Caria
- Biocentre, Johannes Gutenberg-University Mainz, Hans-Dieter-Hüsch-Weg 15, 555128 Mainz, Germany.,Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.,European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Edward A Lemke
- Biocentre, Johannes Gutenberg-University Mainz, Hans-Dieter-Hüsch-Weg 15, 555128 Mainz, Germany .,Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany.,European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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21
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Jans DA, Wagstaff KM. The broad spectrum host-directed agent ivermectin as an antiviral for SARS-CoV-2 ? Biochem Biophys Res Commun 2020; 538:163-172. [PMID: 33341233 PMCID: PMC7577703 DOI: 10.1016/j.bbrc.2020.10.042] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 10/18/2020] [Indexed: 12/16/2022]
Abstract
FDA approved for parasitic indications, the small molecule ivermectin has been the focus of growing attention in the last 8 years due to its potential as an antiviral. We first identified ivermectin in a high throughput compound library screen as an agent potently able to inhibit recognition of the nuclear localizing Human Immunodeficiency Virus-1 (HIV-1) integrase protein by the host importin (IMP) α/β1 heterodimer, and recently demonstrated its ability to bind directly to IMPα to cause conformational changes that prevent its function in nuclear import of key viral as well as host proteins. Cell culture experiments have shown robust antiviral action towards a whole range of viruses, including HIV-1, dengue, Zika and West Nile Virus, Venezuelan equine encephalitis virus, Chikungunya, pseudorabies virus, adenovirus, and SARS-CoV-2 (COVID-19). Close to 70 clinical trials are currently in progress worldwide for SARS-CoV-2. Although few of these studies have been completed, the results that are available, as well as those from observational/retrospective studies, indicate clinical benefit. Here we discuss the case for ivermectin as a host-directed broad-spectrum antiviral agent, including for SARS-CoV-2.
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Affiliation(s)
- David A Jans
- Nuclear Signaling Lab., Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia.
| | - Kylie M Wagstaff
- Cancer Targeting and Nuclear Therapeutics Lab., Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia.
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22
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Mayberry CL, Maginnis MS. Taking the Scenic Route: Polyomaviruses Utilize Multiple Pathways to Reach the Same Destination. Viruses 2020; 12:v12101168. [PMID: 33076363 PMCID: PMC7602598 DOI: 10.3390/v12101168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 01/02/2023] Open
Abstract
Members of the Polyomaviridae family differ in their host range, pathogenesis, and disease severity. To date, some of the most studied polyomaviruses include human JC, BK, and Merkel cell polyomavirus and non-human subspecies murine and simian virus 40 (SV40) polyomavirus. Although dichotomies in host range and pathogenesis exist, overlapping features of the infectious cycle illuminate the similarities within this virus family. Of particular interest to human health, JC, BK, and Merkel cell polyomavirus have all been linked to critical, often fatal, illnesses, emphasizing the importance of understanding the underlying viral infections that result in the onset of these diseases. As there are significant overlaps in the capacity of polyomaviruses to cause disease in their respective hosts, recent advancements in characterizing the infectious life cycle of non-human murine and SV40 polyomaviruses are key to understanding diseases caused by their human counterparts. This review focuses on the molecular mechanisms by which different polyomaviruses hijack cellular processes to attach to host cells, internalize, traffic within the cytoplasm, and disassemble within the endoplasmic reticulum (ER), prior to delivery to the nucleus for viral replication. Unraveling the fundamental processes that facilitate polyomavirus infection provides deeper insight into the conserved mechanisms of the infectious process shared within this virus family, while also highlighting critical unique viral features.
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Affiliation(s)
- Colleen L. Mayberry
- Department of Molecular and Biomedical Sciences, The University of Maine, Orono, ME 04469, USA;
| | - Melissa S. Maginnis
- Department of Molecular and Biomedical Sciences, The University of Maine, Orono, ME 04469, USA;
- Graduate School in Biomedical Sciences and Engineering, The University of Maine, Orono, ME 04469, USA
- Correspondence:
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23
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Ivermectin as a Broad-Spectrum Host-Directed Antiviral: The Real Deal? Cells 2020; 9:cells9092100. [PMID: 32942671 PMCID: PMC7564151 DOI: 10.3390/cells9092100] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/04/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022] Open
Abstract
The small molecule macrocyclic lactone ivermectin, approved by the US Food and Drug Administration for parasitic infections, has received renewed attention in the last eight years due to its apparent exciting potential as an antiviral. It was identified in a high-throughput chemical screen as inhibiting recognition of the nuclear localizing Human Immunodeficiency Virus-1 (HIV-1) integrase protein by the host heterodimeric importin (IMP) α/β1 complex, and has since been shown to bind directly to IMPα to induce conformational changes that prevent its normal function in mediating nuclear import of key viral and host proteins. Excitingly, cell culture experiments show robust antiviral action towards HIV-1, dengue virus (DENV), Zika virus, West Nile virus, Venezuelan equine encephalitis virus, Chikungunya virus, Pseudorabies virus, adenovirus, and SARS-CoV-2 (COVID-19). Phase III human clinical trials have been completed for DENV, with >50 trials currently in progress worldwide for SARS-CoV-2. This mini-review discusses the case for ivermectin as a host-directed broad-spectrum antiviral agent for a range of viruses, including SARS-CoV-2.
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24
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El-Saber Batiha G, Alqahtani A, Ilesanmi OB, Saati AA, El-Mleeh A, Hetta HF, Magdy Beshbishy A. Avermectin Derivatives, Pharmacokinetics, Therapeutic and Toxic Dosages, Mechanism of Action, and Their Biological Effects. Pharmaceuticals (Basel) 2020; 13:E196. [PMID: 32824399 PMCID: PMC7464486 DOI: 10.3390/ph13080196] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/09/2020] [Accepted: 08/13/2020] [Indexed: 12/15/2022] Open
Abstract
Avermectins are a group of drugs that occurs naturally as a product of fermenting Streptomyces avermitilis, an actinomycetes, isolated from the soil. Eight different structures, including ivermectin, abamectin, doramectin, eprinomectin, moxidectin, and selamectin, were isolated and divided into four major components (A1a, A2a, B1a and B2a) and four minor components (A1b, A2b, B1b, and B2b). Avermectins are generally used as a pesticide for the treatment of pests and parasitic worms as a result of their anthelmintic and insecticidal properties. Additionally, they possess anticancer, anti-diabetic, antiviral, antifungal, and are used for treatment of several metabolic disorders. Avermectin generally works by preventing the transmission of electrical impulse in the muscle and nerves of invertebrates, by amplifying the glutamate effects on the invertebrates-specific gated chloride channel. Avermectin has unwanted effects or reactions, especially when administered indiscriminately, which include respiratory failure, hypotension, and coma. The current review examines the mechanism of actions, biosynthesis, safety, pharmacokinetics, biological toxicity and activities of avermectins.
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Affiliation(s)
- Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, Egypt
| | - Ali Alqahtani
- Department of Pharmacology, College of Pharmacy, King Khalid University, Guraiger, Abha 62529, Saudi Arabia;
| | - Omotayo B. Ilesanmi
- Department of Biochemistry, Faculty of Science, Federal University Otuoke, Otuoke 561, Nigeria;
| | - Abdullah A. Saati
- Department of Community Medicine & Pilgrims Healthcare, Faculty of Medicine, Umm Al-Qura University Makkah, Mecca 24382, Saudi Arabia;
| | - Amany El-Mleeh
- Department of Pharmacology, Faculty of Veterinary Medicine, Menoufia University, Shibin Al Kawm 32511, Egypt;
| | - Helal F. Hetta
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut 71515, Egypt;
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45221, USA
| | - Amany Magdy Beshbishy
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-13, Inada-cho, Obihiro 080-8555, Hokkaido, Japan
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25
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Yang SNY, Atkinson SC, Fraser JE, Wang C, Maher B, Roman N, Forwood JK, Wagstaff KM, Borg NA, Jans DA. Novel Flavivirus Antiviral That Targets the Host Nuclear Transport Importin α/β1 Heterodimer. Cells 2019; 8:cells8030281. [PMID: 30909636 PMCID: PMC6468590 DOI: 10.3390/cells8030281] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/19/2019] [Accepted: 03/20/2019] [Indexed: 12/20/2022] Open
Abstract
Dengue virus (DENV) threatens almost 70% of the world’s population, with no effective vaccine or therapeutic currently available. A key contributor to infection is nuclear localisation in the infected cell of DENV nonstructural protein 5 (NS5) through the action of the host importin (IMP) α/β1 proteins. Here, we used a range of microscopic, virological and biochemical/biophysical approaches to show for the first time that the small molecule GW5074 has anti-DENV action through its novel ability to inhibit NS5–IMPα/β1 interaction in vitro as well as NS5 nuclear localisation in infected cells. Strikingly, GW5074 not only inhibits IMPα binding to IMPβ1, but can dissociate preformed IMPα/β1 heterodimer, through targeting the IMPα armadillo (ARM) repeat domain to impact IMPα thermal stability and α-helicity, as shown using analytical ultracentrifugation, thermostability analysis and circular dichroism measurements. Importantly, GW5074 has strong antiviral activity at low µM concentrations against not only DENV-2, but also zika virus and West Nile virus. This work highlights DENV NS5 nuclear targeting as a viable target for anti-flaviviral therapeutics.
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Affiliation(s)
- Sundy N Y Yang
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Sarah C Atkinson
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Johanna E Fraser
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Chunxiao Wang
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Belinda Maher
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Noelia Roman
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia.
| | - Jade K Forwood
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia.
| | - Kylie M Wagstaff
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - Natalie A Borg
- Infection & Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
| | - David A Jans
- Nuclear Signaling Laboratory, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Vic. 3800, Australia.
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26
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PKA-site phosphorylation of importin13 regulates its subcellular localization and nuclear transport function. Biochem J 2018; 475:2699-2712. [PMID: 30045875 DOI: 10.1042/bcj20180082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 07/12/2018] [Accepted: 07/16/2018] [Indexed: 01/25/2023]
Abstract
Importin 13 (IPO13) is a key member of the importin β superfamily, which can transport cargoes both into and out of the nucleus to contribute to a variety of important cellular processes. IPO13 is known to undergo phosphorylation, but the impact of this on function has not been investigated. Here, we show for the first time that IPO13 is phosphorylated by cAMP-dependent protein kinase A specifically at serine 193. Results from fluorescence recovery after photobleaching and fluorescence loss in photobleaching approaches establish that negative charge at serine 193 through phosphorylation or point mutation both reduces IPO13 nuclear import and increases its nuclear export. Importantly, phosphorylation also appears to enhance cargo interaction on the part of IPO13, with significant impact on localization, as shown for the Pax6 homeobox-containing transcription partner. This is the first report that IPO13 can be phosphorylated at Ser193 and that this modification regulates IPO13 subcellular localization and nucleocytoplasmic transport function, with important implications for IPO13's role in development and other processes.
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27
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Leonard A, Rahman A, Fazal F. Importins α and β signaling mediates endothelial cell inflammation and barrier disruption. Cell Signal 2018; 44:103-117. [PMID: 29331583 PMCID: PMC5851016 DOI: 10.1016/j.cellsig.2018.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/03/2018] [Accepted: 01/09/2018] [Indexed: 12/23/2022]
Abstract
Nucleocytoplasmic shuttling via importins is central to the function of eukaryotic cells and an integral part of the processes that lead to many human diseases. In this study, we addressed the role of α and β importins in the mechanism of endothelial cell (EC) inflammation and permeability, important pathogenic features of many inflammatory diseases such as acute lung injury and atherosclerosis. RNAi-mediated knockdown of importin α4 or α3 each inhibited NF-κB activation, proinflammatory gene (ICAM-1, VCAM-1, and IL-6) expression, and thereby endothelial adhesivity towards HL-60 cells, upon thrombin challenge. The inhibitory effect of α4 and α3 knockdown was associated with impaired nuclear import and consequently, DNA binding of RelA/p65 subunit of NF-κB and occurred independently of IκBα degradation. Intriguingly, knockdown of importins α4 and α3 also inhibited thrombin-induced RelA/p65 phosphorylation at Ser536, showing a novel role of α importins in regulating transcriptional activity of RelA/p65. Similarly, knockdown of importin β1, but not β2, blocked thrombin-induced activation of RelA/p65 and its target genes. In parallel studies, TNFα-mediated inflammatory responses in EC were refractory to knockdown of importins α4, α3 or β1, indicating a stimulus-specific regulation of RelA/p65 and EC inflammation by these importins. Importantly, α4, α3, or β1 knockdown also protected against thrombin-induced EC barrier disruption by inhibiting the loss of VE-cadherin at adherens junctions and by regulating actin cytoskeletal rearrangement. These results identify α4, α3 and β1 as critical mediators of EC inflammation and permeability associated with intravascular coagulation.
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Affiliation(s)
- Antony Leonard
- Department of Pediatrics (Neonatology), Lung Biology and Disease Program, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States
| | - Arshad Rahman
- Department of Pediatrics (Neonatology), Lung Biology and Disease Program, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States
| | - Fabeha Fazal
- Department of Pediatrics (Neonatology), Lung Biology and Disease Program, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States.
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28
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Jans DA, Martin AJ. Nucleocytoplasmic Trafficking of Dengue Non-structural Protein 5 as a Target for Antivirals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1062:199-213. [DOI: 10.1007/978-981-10-8727-1_15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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29
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Novel inhibitors targeting Venezuelan equine encephalitis virus capsid protein identified using In Silico Structure-Based-Drug-Design. Sci Rep 2017; 7:17705. [PMID: 29255256 PMCID: PMC5735092 DOI: 10.1038/s41598-017-17672-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 11/29/2017] [Indexed: 11/09/2022] Open
Abstract
Therapeutics are currently unavailable for Venezuelan equine encephalitis virus (VEEV), which elicits flu-like symptoms and encephalitis in humans, with an estimated 14% of cases resulting in neurological disease. Here we identify anti-VEEV agents using in silico structure-based-drug-design (SBDD) for the first time, characterising inhibitors that block recognition of VEEV capsid protein (C) by the host importin (IMP) α/β1 nuclear transport proteins. From an initial screen of 1.5 million compounds, followed by in silico refinement and screening for biological activity in vitro, we identified 21 hit compounds which inhibited IMPα/β1:C binding with IC50s as low as 5 µM. Four compounds were found to inhibit nuclear import of C in transfected cells, with one able to reduce VEEV replication at µM concentration, concomitant with reduced C nuclear accumulation in infected cells. Further, this compound was inactive against a mutant VEEV that lacks high affinity IMPα/β1:C interaction, supporting the mode of its antiviral action to be through inhibiting C nuclear localization. This successful application of SBDD paves the way for lead optimization for VEEV antivirals, and is an exciting prospect to identify inhibitors for the many other viral pathogens of significance that require IMPα/β1 in their infectious cycle.
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O-GlcNAc cycling and the regulation of nucleocytoplasmic dynamics. Biochem Soc Trans 2017; 45:427-436. [DOI: 10.1042/bst20160171] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/05/2017] [Accepted: 02/09/2017] [Indexed: 01/01/2023]
Abstract
The dynamic carbohydrate post-translational modification (PTM) O-linked β-N-acetyl glucosamine (O-GlcNAc) is found on thousands of proteins throughout the nucleus and cytoplasm, and rivals phosphorylation in terms of the number of substrates and pathways influenced. O-GlcNAc is highly conserved and essential in most organisms, with disruption of O-GlcNAc cycling linked to diseases ranging from cancer to neurodegeneration. Nuclear pore proteins were the first identified O-GlcNAc-modified substrates, generating intense and ongoing interest in understanding the role of O-GlcNAc cycling in nuclear pore complex structure and function. Recent advances in detecting and altering O-GlcNAcylation levels have provided insights into many mechanisms by which O-GlcNAcylation influences the nucleocytoplasmic localization and stability of protein targets. The emerging view is that the multifunctional enzymes of O-GlcNAc cycling are critical nutrient-sensing components of a complex network of signaling cascades involving multiple PTMs. Furthermore, O-GlcNAc plays a role in maintaining the structural integrity of the nuclear pore and regulating its function as the gatekeeper of nucleocytoplasmic trafficking.
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Bhattacharjee S, Chattaraj S. Entry, infection, replication, and egress of human polyomaviruses: an update. Can J Microbiol 2017; 63:193-211. [DOI: 10.1139/cjm-2016-0519] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Polyomaviruses (PyVs), belonging to the family Polyomaviridae, are a group of small, nonenveloped, double-stranded, circular DNA viruses widely distributed in the vertebrates. PyVs cause no apparent disease in adult laboratory mice but cause a wide variety of tumors when artificially inoculated into neonates or semipermissive animals. A few human PyVs, such as BK, JC, and Merkel cell PyVs, have been unequivocally linked to pathogenesis under conditions of immunosuppression. Infection is thought to occur early in life and persists for the lifespan of the host. Over evolutionary time scales, it appears that PyVs have slowly co-evolved with specific host animal lineages. Host cell surface glycoproteins and glycolipids seem to play a decisive role in the entry stage of viral infection and in channeling the virions to specific intracellular membrane-bound compartments and ultimately to the nucleus, where the genomes are replicated and packaged for release. Therefore the transport of the infecting virion or viral genome to this site of multiplication is an essential process in productive viral infection as well as in latent infection and transformation. This review summarizes the major findings related to the characterization of the nature of the interactions between PyV and host protein and their impact in host cell invasion.
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Affiliation(s)
- Soumen Bhattacharjee
- Cell and Molecular Biology Laboratory, Department of Zoology, University of North Bengal, Raja Rammohunpur, P.O. North Bengal University, Siliguri, District Darjeeling, West Bengal, PIN 734013, India
- Cell and Molecular Biology Laboratory, Department of Zoology, University of North Bengal, Raja Rammohunpur, P.O. North Bengal University, Siliguri, District Darjeeling, West Bengal, PIN 734013, India
| | - Sutanuka Chattaraj
- Cell and Molecular Biology Laboratory, Department of Zoology, University of North Bengal, Raja Rammohunpur, P.O. North Bengal University, Siliguri, District Darjeeling, West Bengal, PIN 734013, India
- Cell and Molecular Biology Laboratory, Department of Zoology, University of North Bengal, Raja Rammohunpur, P.O. North Bengal University, Siliguri, District Darjeeling, West Bengal, PIN 734013, India
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Lundberg L, Pinkham C, de la Fuente C, Brahms A, Shafagati N, Wagstaff KM, Jans DA, Tamir S, Kehn-Hall K. Selective Inhibitor of Nuclear Export (SINE) Compounds Alter New World Alphavirus Capsid Localization and Reduce Viral Replication in Mammalian Cells. PLoS Negl Trop Dis 2016; 10:e0005122. [PMID: 27902702 PMCID: PMC5130180 DOI: 10.1371/journal.pntd.0005122] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 10/21/2016] [Indexed: 01/28/2023] Open
Abstract
The capsid structural protein of the New World alphavirus, Venezuelan equine encephalitis virus (VEEV), interacts with the host nuclear transport proteins importin α/β1 and CRM1. Novel selective inhibitor of nuclear export (SINE) compounds, KPT-185, KPT-335 (verdinexor), and KPT-350, target the host's primary nuclear export protein, CRM1, in a manner similar to the archetypical inhibitor Leptomycin B. One major limitation of Leptomycin B is its irreversible binding to CRM1; which SINE compounds alleviate because they are slowly reversible. Chemically inhibiting CRM1 with these compounds enhanced capsid localization to the nucleus compared to the inactive compound KPT-301, as indicated by immunofluorescent confocal microscopy. Differences in extracellular versus intracellular viral RNA, as well as decreased capsid in cell free supernatants, indicated the inhibitors affected viral assembly, which led to a decrease in viral titers. The decrease in viral replication was confirmed using a luciferase-tagged virus and through plaque assays. SINE compounds had no effect on VEEV TC83_Cm, which encodes a mutated form of capsid that is unable to enter the nucleus. Serially passaging VEEV in the presence of KPT-185 resulted in mutations within the nuclear localization and nuclear export signals of capsid. Finally, SINE compound treatment also reduced the viral titers of the related eastern and western equine encephalitis viruses, suggesting that CRM1 maintains a common interaction with capsid proteins across the New World alphavirus genus.
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Affiliation(s)
- Lindsay Lundberg
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Chelsea Pinkham
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Cynthia de la Fuente
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Ashwini Brahms
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Nazly Shafagati
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Kylie M. Wagstaff
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - David A. Jans
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Sharon Tamir
- Karyopharm Therapeutics Inc., Massachusetts, United States of America
| | - Kylene Kehn-Hall
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
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Stratigi K, Chatzidoukaki O, Garinis GA. DNA damage-induced inflammation and nuclear architecture. Mech Ageing Dev 2016; 165:17-26. [PMID: 27702596 DOI: 10.1016/j.mad.2016.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 09/20/2016] [Accepted: 09/25/2016] [Indexed: 12/12/2022]
Abstract
Nuclear architecture and the chromatin state affect most-if not all- DNA-dependent transactions, including the ability of cells to sense DNA lesions and restore damaged DNA back to its native form. Recent evidence points to functional links between DNA damage sensors, DNA repair mechanisms and the innate immune responses. The latter raises the question of how such seemingly disparate processes operate within the intrinsically complex nuclear landscape and the chromatin environment. Here, we discuss how DNA damage-induced immune responses operate within chromatin and the distinct sub-nuclear compartments highlighting their relevance to chronic inflammation.
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Affiliation(s)
- Kalliopi Stratigi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013, Heraklion, Crete, Greece
| | - Ourania Chatzidoukaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013, Heraklion, Crete, Greece
| | - George A Garinis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira 100, 70013, Heraklion, Crete, Greece; Department of Biology, University of Crete, Vassilika Vouton, GR71409, Heraklion, Crete, Greece.
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Dynamic Nucleolar Targeting of Dengue Virus Polymerase NS5 in Response to Extracellular pH. J Virol 2016; 90:5797-5807. [PMID: 27076639 DOI: 10.1128/jvi.02727-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 02/29/2016] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED The nucleolar subcompartment of the nucleus is increasingly recognized as an important target of RNA viruses. Here we document for the first time the ability of dengue virus (DENV) polymerase, nonstructural protein 5 (NS5), to accumulate within the nucleolus of infected cells and to target green fluorescent protein (GFP) to the nucleolus of live transfected cells. Intriguingly, NS5 exchange between the nucleus and nucleolus is dynamically modulated by extracellular pH, responding rapidly and reversibly to pH change, in contrast to GFP alone or other nucleolar and non-nucleolar targeted protein controls. The minimal pH-sensitive nucleolar targeting region (pHNTR), sufficient to target GFP to the nucleolus in a pH-sensitive fashion, was mapped to NS5 residues 1 to 244, with mutation of key hydrophobic residues, Leu-165, Leu-167, and Val-168, abolishing pHNTR function in NS5-transfected cells, and severely attenuating DENV growth in infected cells. This is the first report of a viral protein whose nucleolar targeting ability is rapidly modulated by extracellular stimuli, suggesting that DENV has the ability to detect and respond dynamically to the extracellular environment. IMPORTANCE Infections by dengue virus (DENV) threaten 40% of the world's population yet there is no approved vaccine or antiviral therapeutic to treat infections. Understanding the molecular details that govern effective viral replication is key for the development of novel antiviral strategies. Here, we describe for the first time dynamic trafficking of DENV nonstructural protein 5 (NS5) to the subnuclear compartment, the nucleolus. We demonstrate that NS5's targeting to the nucleolus occurs in response to acidic pH, identify the key amino acid residues within NS5 that are responsible, and demonstrate that their mutation severely impairs production of infectious DENV. Overall, this study identifies a unique subcellular trafficking event and suggests that DENV is able to detect and respond dynamically to environmental changes.
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Lee YJ, Lee C. Ivermectin inhibits porcine reproductive and respiratory syndrome virus in cultured porcine alveolar macrophages. Arch Virol 2015; 161:257-68. [PMID: 26518309 DOI: 10.1007/s00705-015-2653-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 10/18/2015] [Indexed: 11/28/2022]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is a devastating viral pathogen of swine that causes huge financial losses in the pig industry worldwide. Ivermectin is known to be a potent inhibitor of importin α/β-mediated nuclear transport and exhibits antiviral activity towards several RNA viruses by blocking the nuclear trafficking of viral proteins. Although PRRSV replication occurs exclusively in the cytoplasm of infected cells, the nucleocapsid (N) protein has been shown to distinctly localize in the nucleus and nucleolus throughout infection. Here, we sought to assess whether ivermectin suppresses PRRSV replication in cultured porcine alveolar macrophage (PAM) cells and to investigate the effect of ivermectin on the subcellular localization of the PRRSV N protein. Our data demonstrate that ivermectin treatment inhibits PRRSV infection in PAM-pCD163 cells in a dose-dependent manner. The antiviral activity of ivermectin on PRRSV replication was most effective when cells were treated during the early stage of infection. Treatment of PRRSV-infected cells with ivermectin significantly suppressed viral RNA synthesis, viral protein expression, and progeny virus production. However, immunofluorescence and cell fractionation assays revealed that ivermectin was incapable of disrupting the nuclear localization of the N protein, both in PRRSV-infected PAM-pCD163 cells and in PAM cells stably expressing the PRRSV N protein. This finding suggests that an alternative mechanism of action accounts for the ability of ivermectin to diminish PRRSV replication. Taken together, our results suggest that ivermectin is an invaluable therapeutic or preventative agent against PRRSV infection.
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Affiliation(s)
- Yoo Jin Lee
- Animal Virology Laboratory, School of Life Sciences, College of Natural Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, 702-701, Republic of Korea
| | - Changhee Lee
- Animal Virology Laboratory, School of Life Sciences, College of Natural Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, 702-701, Republic of Korea.
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Caly L, Ghildyal R, Jans DA. Respiratory virus modulation of host nucleocytoplasmic transport; target for therapeutic intervention? Front Microbiol 2015; 6:848. [PMID: 26322040 PMCID: PMC4536372 DOI: 10.3389/fmicb.2015.00848] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/03/2015] [Indexed: 01/02/2023] Open
Abstract
The respiratory diseases caused by rhinovirus, respiratory syncytial virus, and influenza virus represent a large social and financial burden on healthcare worldwide. Although all three viruses have distinctly unique properties in terms of infection and replication, they share the ability to exploit/manipulate the host-cell nucleocytoplasmic transport system in order to replicate effectively and efficiently. This review outlines the various ways in which infection by these viruses impacts on the host nucleocytoplasmic transport system, and examples where inhibition thereof in turn decreases viral replication. The highly conserved nature of the nucleocytoplasmic transport system and the viral proteins that interact with it make this virus–host interface a prime candidate for the development of specific antiviral therapeutics in the future.
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Affiliation(s)
- Leon Caly
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC Australia
| | - Reena Ghildyal
- Faculty of ESTeM, University of Canberra, Bruce, ACT Australia
| | - David A Jans
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC Australia
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Hennig T, O'Hare P. Viruses and the nuclear envelope. Curr Opin Cell Biol 2015; 34:113-21. [PMID: 26121672 DOI: 10.1016/j.ceb.2015.06.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 10/23/2022]
Abstract
Viruses encounter and manipulate almost all aspects of cell structure and metabolism. The nuclear envelope (NE), with central roles in cell structure and genome function, acts and is usurped in diverse ways by different viruses. It can act as a physical barrier to infection that must be overcome, as a functional barrier that restricts infection by various mechanisms and must be counteracted or indeed as a positive niche, important or even essential for virus infection or production of progeny virions. This review summarizes virus-host interactions at the NE, highlighting progress in understanding the replication of viruses including HIV-1, Influenza, Herpes Simplex, Adenovirus and Ebola, and molecular insights into hitherto unknown functional pathways at the NE.
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Affiliation(s)
- Thomas Hennig
- Section of Virology, Faculty of Medicine, Imperial College, London W2 1PG, United Kingdom
| | - Peter O'Hare
- Section of Virology, Faculty of Medicine, Imperial College, London W2 1PG, United Kingdom.
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Wulan WN, Heydet D, Walker EJ, Gahan ME, Ghildyal R. Nucleocytoplasmic transport of nucleocapsid proteins of enveloped RNA viruses. Front Microbiol 2015; 6:553. [PMID: 26082769 PMCID: PMC4451415 DOI: 10.3389/fmicb.2015.00553] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/19/2015] [Indexed: 12/25/2022] Open
Abstract
Most viruses with non-segmented single stranded RNA genomes complete their life cycle in the cytoplasm of infected cells. However, despite undergoing replication in the cytoplasm, the structural proteins of some of these RNA viruses localize to the nucleus at specific times in the virus life cycle, primarily early in infection. Limited evidence suggests that this enhances successful viral replication by interfering with or inhibiting the host antiviral response. Nucleocapsid proteins of RNA viruses have a well-established, essential cytoplasmic role in virus replication and assembly. Intriguingly, nucleocapsid proteins of some RNA viruses also localize to the nucleus/nucleolus of infected cells. Their nuclear function is less well understood although significant advances have been made in recent years. This review will focus on the nucleocapsid protein of cytoplasmic enveloped RNA viruses, including their localization to the nucleus/nucleolus and function therein. A greater understanding of the nuclear localization of nucleocapsid proteins has the potential to enhance therapeutic strategies as it can be a target for the development of live-attenuated vaccines or antiviral drugs.
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Affiliation(s)
- Wahyu N Wulan
- Centre for Research in Therapeutic Solutions, University of Canberra, Bruce, ACT Australia ; Faculty of Education, Science, Technology and Mathematics, University of Canberra, Bruce, ACT Australia
| | - Deborah Heydet
- Centre for Research in Therapeutic Solutions, University of Canberra, Bruce, ACT Australia
| | - Erin J Walker
- Centre for Research in Therapeutic Solutions, University of Canberra, Bruce, ACT Australia
| | - Michelle E Gahan
- Faculty of Education, Science, Technology and Mathematics, University of Canberra, Bruce, ACT Australia
| | - Reena Ghildyal
- Centre for Research in Therapeutic Solutions, University of Canberra, Bruce, ACT Australia ; Faculty of Education, Science, Technology and Mathematics, University of Canberra, Bruce, ACT Australia
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Abstract
DNA viruses undertake their replication within the cell nucleus, and therefore they must first deliver their genome into the nucleus of their host cells. Thus, trafficking across the nuclear envelope is at the basis of DNA virus infections. Nuclear transport of molecules with diameters up to 39 nm is a tightly regulated process that occurs through the nuclear pore complex (NPC). Due to the enormous diversity of virus size and structure, each virus has developed its own strategy for entering the nucleus of their host cells, with no two strategies alike. For example, baculoviruses target their DNA-containing capsid to the NPC and subsequently enter the nucleus intact, while the hepatitis B virus capsid crosses the NPC but disassembles at the nuclear side of the NPC. For other viruses such as herpes simplex virus and adenovirus, although both dock at the NPC, they have each developed a distinct mechanism for the subsequent delivery of their genome into the nucleus. Remarkably, other DNA viruses, such as parvoviruses and human papillomaviruses, access the nucleus through an NPC-independent mechanism. This review discusses our current understanding of the mechanisms used by DNA viruses to deliver their genome into the nucleus, and further presents the experimental evidence for such mechanisms.
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Affiliation(s)
- Nikta Fay
- Department of Zoology, University of British Columbia Vancouver, BC, Canada
| | - Nelly Panté
- Department of Zoology, University of British Columbia Vancouver, BC, Canada
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Carter DM, Westdorp K, Noon KR, Terhune SS. Proteomic identification of nuclear processes manipulated by cytomegalovirus early during infection. Proteomics 2015; 15:1995-2005. [PMID: 25758553 DOI: 10.1002/pmic.201400599] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/20/2015] [Accepted: 03/07/2015] [Indexed: 11/07/2022]
Abstract
Human cytomegalovirus (HCMV) is a herpesvirus that is ubiquitously distributed worldwide and causes life-threating disease upon immunosuppression. HCMV expresses numerous proteins that function to establish an intracellular environment that supports viral replication. Like most DNA viruses, HCMV manipulates processes within the nucleus. We have quantified changes in the host cell nuclear proteome at 24 h post infection following infection with a clinical viral isolate. We have combined SILAC with multiple stages of fractionation to define changes. Tryptic peptides were analyzed by RP-HPLC combined with LC-MS/MS on an LTQ Orbitrap Velos mass spectrometer. Data from three biological replicates were processed with MaxQuant. A total of 1281 cellular proteins were quantified and 77 were found to be significantly differentially expressed. In addition, we observed 36 viral proteins associated with the nucleus. Diverse biological processes were significantly altered, including increased aspects of cell cycling, mRNA metabolism, and nucleocytoplasmic transport and decreased immune responses. We validated changes for several proteins including a subset of classical nuclear transport proteins. In addition, we demonstrated that disruption of these import factors is inhibitory to HCMV replication. Overall, we have identified HCMV-induced changes in the nuclear proteome and uncovered several processes that are important for infection. All MS data have been deposited in the ProteomeXchange with identifier PXD001909 (http://proteomecentral.proteomexchange.org/dataset/PXD001909).
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Affiliation(s)
- Dominique M Carter
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI, USA
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Kristen Westdorp
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI, USA
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Kathleen R Noon
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Scott S Terhune
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI, USA
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, USA
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Fay N, Panté N. Old foes, new understandings: nuclear entry of small non-enveloped DNA viruses. Curr Opin Virol 2015; 12:59-65. [PMID: 25846849 DOI: 10.1016/j.coviro.2015.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 03/11/2015] [Accepted: 03/23/2015] [Indexed: 01/03/2023]
Abstract
The nuclear import of viral genomes is an important step of the infectious cycle for viruses that replicate in the nucleus of their host cells. Although most viruses use the cellular nuclear import machinery or some components of this machinery, others have developed sophisticated ways to reach the nucleus. Some of these have been known for some time; however, recent studies have changed our understanding of how some non-enveloped DNA viruses access the nucleus. For example, parvoviruses enter the nucleus through small disruptions of the nuclear membranes and nuclear lamina, and adenovirus tugs at the nuclear pore complex, using kinesin-1, to disassemble their capsids and deliver viral proteins and genomes into the nucleus. Here we review recent findings of the nuclear import strategies of three small non-enveloped DNA viruses, including adenovirus, parvovirus, and the polyomavirus simian virus 40.
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Affiliation(s)
- Nikta Fay
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
| | - Nelly Panté
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada.
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Chen A, T-Thienprasert NP, Brown CM. Prospects for inhibiting the post-transcriptional regulation of gene expression in hepatitis B virus. World J Gastroenterol 2014; 20:7993-8004. [PMID: 25009369 PMCID: PMC4081668 DOI: 10.3748/wjg.v20.i25.7993] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/19/2014] [Accepted: 04/09/2014] [Indexed: 02/06/2023] Open
Abstract
There is a continuing need for novel antivirals to treat hepatitis B virus (HBV) infection, as it remains a major health problem worldwide. Ideally new classes of antivirals would target multiple steps in the viral lifecycle. In this review, we consider the steps in which HBV RNAs are processed, exported from the nucleus and translated. These are often overlooked steps in the HBV life-cycle. HBV, like retroviruses, incorporates a number of unusual steps in these processes, which use a combination of viral and host cellular machinery. Some of these unusual steps deserve a closer scrutiny. They may provide alternative targets to existing antiviral therapies, which are associated with increasing drug resistance. The RNA post-transcriptional regulatory element identified 20 years ago promotes nucleocytoplasmic export of all unspliced HBV RNAs. There is evidence that inhibition of this step is part of the antiviral action of interferon. Similarly, the structured RNA epsilon element situated at the 5’ end of the polycistronic HBV pregenomic RNA also performs key roles during HBV replication. The pregenomic RNA, which is the template for translation of both the viral core and polymerase proteins, is also encapsidated and used in replication. This complex process, regulated at the epsilon element, also presents an attractive antiviral target. These RNA elements that mediate and regulate gene expression are highly conserved and could be targeted using novel strategies employing RNAi, miRNAs or aptamers. Such approaches targeting these functionally constrained genomic regions should avoid escape mutations. Therefore understanding these regulatory elements, along with providing potential targets, may also facilitate the development of other new classes of antiviral drugs.
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Van Damme E, Van Loock M. Functional annotation of human cytomegalovirus gene products: an update. Front Microbiol 2014; 5:218. [PMID: 24904534 PMCID: PMC4032930 DOI: 10.3389/fmicb.2014.00218] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 04/25/2014] [Indexed: 01/31/2023] Open
Abstract
Human cytomegalovirus is an opportunistic double-stranded DNA virus with one of the largest viral genomes known. The 235 kB genome is divided in a unique long (UL) and a unique short (US) region which are flanked by terminal and internal repeats. The expression of HCMV genes is highly complex and involves the production of protein coding transcripts, polyadenylated long non-coding RNAs, polyadenylated anti-sense transcripts and a variety of non-polyadenylated RNAs such as microRNAs. Although the function of many of these transcripts is unknown, they are suggested to play a direct or regulatory role in the delicately orchestrated processes that ensure HCMV replication and life-long persistence. This review focuses on annotating the complete viral genome based on three sources of information. First, previous reviews were used as a template for the functional keywords to ensure continuity; second, the Uniprot database was used to further enrich the functional database; and finally, the literature was manually curated for novel functions of HCMV gene products. Novel discoveries were discussed in light of the viral life cycle. This functional annotation highlights still poorly understood regions of the genome but more importantly it can give insight in functional clusters and/or may be helpful in the analysis of future transcriptomics and proteomics studies.
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Affiliation(s)
- Ellen Van Damme
- Janssen Infectious Diseases BVBA, Therapeutic Area of Infectious Diseases Beerse, Belgium
| | - Marnix Van Loock
- Janssen Infectious Diseases BVBA, Therapeutic Area of Infectious Diseases Beerse, Belgium
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Forbes N, Selman M, Pelchat M, Jia JJ, Stintzi A, Brown EG. Identification of adaptive mutations in the influenza A virus non-structural 1 gene that increase cytoplasmic localization and differentially regulate host gene expression. PLoS One 2013; 8:e84673. [PMID: 24391972 PMCID: PMC3877356 DOI: 10.1371/journal.pone.0084673] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 11/18/2013] [Indexed: 12/22/2022] Open
Abstract
The NS1 protein of influenza A virus (IAV) is a multifunctional virulence factor. We have previously characterized gain-of-function mutations in the NS1 protein arising from the experimental adaptation of the human isolate A/Hong Kong/1/1968(H3N2) (HK) to the mouse. The majority of these mouse adapted NS1 mutations were demonstrated to increase virulence, viral fitness, and interferon antagonism, but differ in binding to the post-transcriptional processing factor cleavage and polyadenylation specificity factor 30 (CPSF30). Because nuclear trafficking is a major genetic determinant of influenza virus host adaptation, we assessed subcellular localization and host gene expression of NS1 adaptive mutations. Recombinant HK viruses with adaptive mutations in the NS1 gene were assessed for NS1 protein subcellular localization in mouse and human cells using confocal microscopy and cellular fractionation. In human cells the HK wild-type (HK-wt) virus NS1 protein partitioned equivalently between the cytoplasm and nucleus but was defective in cytoplasmic localization in mouse cells. Several adaptive mutations increased the proportion of NS1 in the cytoplasm of mouse cells with the greatest effects for mutations M106I and D125G. The host gene expression profile of the adaptive mutants was determined by microarray analysis of infected mouse cells to show either high or low extents of host-gene regulation (HGR or LGR) phenotypes. While host genes were predominantly down regulated for the HGR group of mutants (D2N, V23A, F103L, M106I+L98S, L98S, M106V, and M106V+M124I), the LGR phenotype mutants (D125G, M106I, V180A, V226I, and R227K) were characterized by a predominant up regulation of host genes. CPSF30 binding affinity of NS1 mutants did not predict effects on host gene expression. To our knowledge this is the first report of roles of adaptive NS1 mutations that impact intracellular localization and regulation of host gene expression.
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Affiliation(s)
- Nicole Forbes
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Emerging Pathogens Research Centre, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Mohammed Selman
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Emerging Pathogens Research Centre, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Martin Pelchat
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Jian Jun Jia
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Alain Stintzi
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Earl G. Brown
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Emerging Pathogens Research Centre, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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Bioinformatical analysis of nuclear localisation sequences in penaeid densoviruses. Mar Genomics 2013; 12:9-15. [DOI: 10.1016/j.margen.2013.10.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/11/2013] [Indexed: 02/05/2023]
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Regulated transport into the nucleus of herpesviridae DNA replication core proteins. Viruses 2013; 5:2210-34. [PMID: 24064794 PMCID: PMC3798897 DOI: 10.3390/v5092210] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/03/2013] [Accepted: 09/04/2013] [Indexed: 12/11/2022] Open
Abstract
The Herpesvirdae family comprises several major human pathogens belonging to three distinct subfamilies. Their double stranded DNA genome is replicated in the nuclei of infected cells by a number of host and viral products. Among the latter the viral replication complex, whose activity is strictly required for viral replication, is composed of six different polypeptides, including a two-subunit DNA polymerase holoenzyme, a trimeric primase/helicase complex and a single stranded DNA binding protein. The study of herpesviral DNA replication machinery is extremely important, both because it provides an excellent model to understand processes related to eukaryotic DNA replication and it has important implications for the development of highly needed antiviral agents. Even though all known herpesviruses utilize very similar mechanisms for amplification of their genomes, the nuclear import of the replication complex components appears to be a heterogeneous and highly regulated process to ensure the correct spatiotemporal localization of each protein. The nuclear transport process of these enzymes is controlled by three mechanisms, typifying the main processes through which protein nuclear import is generally regulated in eukaryotic cells. These include cargo post-translational modification-based recognition by the intracellular transporters, piggy-back events allowing coordinated nuclear import of multimeric holoenzymes, and chaperone-assisted nuclear import of specific subunits. In this review we summarize these mechanisms and discuss potential implications for the development of antiviral compounds aimed at inhibiting the Herpesvirus life cycle by targeting nuclear import of the Herpesvirus DNA replicating enzymes.
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Nucleocytoplasmic shuttling of viral proteins in borna disease virus infection. Viruses 2013; 5:1978-90. [PMID: 23965528 PMCID: PMC3761237 DOI: 10.3390/v5081978] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/02/2013] [Accepted: 08/05/2013] [Indexed: 12/20/2022] Open
Abstract
Nuclear import and export of viral RNA and proteins are critical to the replication cycle of viruses that replicate in the nucleus. Borna disease virus (BDV) is a nonsegmented, negative-strand RNA virus that belongs to the order Mononegavirales. BDV has several distinguishing features, one of the most striking being the site of its replication. BDV RNA is transcribed and replicated in the nucleus, while most other negative-strand RNA viruses replicate in the cytoplasm. Therefore, the nucleocytoplasmic trafficking of BDV macromolecules plays a key role in virus replication. Growing evidence indicates that several BDV proteins, including the nucleoprotein, phosphoprotein, protein X and large protein, contribute to the nucleocytoplasmic trafficking of BDV ribonucleoprotein (RNP). The directional control of BDV RNP trafficking is likely determined by the ratios of and interactions between the nuclear localization signals and nuclear export signals in the RNP. In this review, we present a comprehensive view of several unique mechanisms that BDV has developed to control its RNP trafficking and discuss the significance of BDV RNP trafficking in the replication cycle of BDV.
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Walker EJ, Younessi P, Fulcher AJ, McCuaig R, Thomas BJ, Bardin PG, Jans DA, Ghildyal R. Rhinovirus 3C protease facilitates specific nucleoporin cleavage and mislocalisation of nuclear proteins in infected host cells. PLoS One 2013; 8:e71316. [PMID: 23951130 PMCID: PMC3737158 DOI: 10.1371/journal.pone.0071316] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/28/2013] [Indexed: 12/18/2022] Open
Abstract
Human Rhinovirus (HRV) infection results in shut down of essential cellular processes, in part through disruption of nucleocytoplasmic transport by cleavage of the nucleoporin proteins (Nups) that make up the host cell nuclear pore. Although the HRV genome encodes two proteases (2A and 3C) able to cleave host proteins such as Nup62, little is known regarding the specific contribution of each. Here we use transfected as well as HRV-infected cells to establish for the first time that 3C protease is most likely the mediator of cleavage of Nup153 during HRV infection, while Nup62 and Nup98 are likely to be targets of HRV2A protease. HRV16 3C protease was also able to elicit changes in the appearance and distribution of the nuclear speckle protein SC35 in transfected cells, implicating it as a key mediator of the mislocalisation of SC35 in HRV16-infected cells. In addition, 3C protease activity led to the redistribution of the nucleolin protein out of the nucleolus, but did not affect nuclear localisation of hnRNP proteins, implying that complete disruption of nucleocytoplasmic transport leading to relocalisation of hnRNP proteins from the nucleus to the cytoplasm in HRV-infected cells almost certainly requires 2A in addition to 3C protease. Thus, a specific role for HRV 3C protease in cleavage and mislocalisation of host cell nuclear proteins, in concert with 2A, is implicated for the first time in HRV pathogenesis.
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Affiliation(s)
- Erin J. Walker
- Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Parisa Younessi
- Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Alex J. Fulcher
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Robert McCuaig
- Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Belinda J. Thomas
- Monash Institute of Medical Research and Monash Lung & Sleep, Monash Medical Centre, Clayton, Victoria, Australia
| | - Philip G. Bardin
- Monash Institute of Medical Research and Monash Lung & Sleep, Monash Medical Centre, Clayton, Victoria, Australia
| | - David A. Jans
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Reena Ghildyal
- Centre for Research in Therapeutic Solutions, University of Canberra, Canberra, Australian Capital Territory, Australia
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Dankar SK, Miranda E, Forbes NE, Pelchat M, Tavassoli A, Selman M, Ping J, Jia J, Brown EG. Influenza A/Hong Kong/156/1997(H5N1) virus NS1 gene mutations F103L and M106I both increase IFN antagonism, virulence and cytoplasmic localization but differ in binding to RIG-I and CPSF30. Virol J 2013; 10:243. [PMID: 23886034 PMCID: PMC3733596 DOI: 10.1186/1743-422x-10-243] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/23/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The genetic basis for avian to mammalian host switching in influenza A virus is largely unknown. The human A/HK/156/1997 (H5N1) virus that transmitted from poultry possesses NS1 gene mutations F103L + M106I that are virulence determinants in the mouse model of pneumonia; however their individual roles have not been determined. The emergent A/Shanghai/patient1/2013(H7N9)-like viruses also possess these mutations which may contribute to their virulence and ability to switch species. METHODS NS1 mutant viruses were constructed by reverse genetics and site directed mutagenesis on human and mouse-adapted backbones. Mouse infections assessed virulence, virus yield, tissue infection, and IFN induction. NS1 protein properties were assessed for subcellular distribution, IFN antagonism (mouse and human), CPSF30 and RIG-I domain binding, host transcription (microarray); and the natural prevalence of 103L and 106I mutants was assessed. RESULTS Each of the F103L and M106I mutations contributes additively to virulence to reduce the lethal dose by >800 and >3,200 fold respectively by mediating alveolar tissue infection with >100 fold increased infectious yields. The 106I NS1 mutant lost CPSF binding but the 103L mutant maintained binding that correlated with an increased general decrease in host gene expression in human but not mouse cells. Each mutation positively modulated the inhibition of IFN induction in mouse cells and activation of the IFN-β promoter in human cells but not in combination in human cells indicating negative epistasis. Each of the F103L and M106I mutations restored a defect in cytoplasmic localization of H5N1 NS1 in mouse cells. Human H1N1 and H3N2 NS1 proteins bound to the CARD, helicase and RD RIG-I domains, whereas the H5N1 NS1 with the same consensus 103F and 106M mutations did not bind these domains, which was totally or partially restored by the M106I or F103L mutations respectively. CONCLUSIONS The F103L and M106I mutations in the H5N1 NS1 protein each increased IFN antagonism and mediated interstitial pneumonia in mice that was associated with increased cytoplasmic localization and altered host factor binding. These mutations may contribute to the ability of previous HPAI H5N1 and recent LPAI H7N9 and H6N1 (NS1-103L+106M) viruses to switch hosts and cause disease in humans.
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Affiliation(s)
- Samar K Dankar
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Rd, Ottawa, Ontario K1H 8M5, Canada
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Hannemann H, Sung PY, Chiu HC, Yousuf A, Bird J, Lim SP, Davidson AD. Serotype-specific differences in dengue virus non-structural protein 5 nuclear localization. J Biol Chem 2013; 288:22621-35. [PMID: 23770669 DOI: 10.1074/jbc.m113.481382] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The four serotypes of dengue virus (DENV-1 to -4) cause the most important arthropod-borne viral disease of humans. DENV non-structural protein 5 (NS5) contains enzymatic activities required for capping and replication of the viral RNA genome that occurs in the host cytoplasm. However, previous studies have shown that DENV-2 NS5 accumulates in the nucleus during infection. In this study, we examined the nuclear localization of NS5 for all four DENV serotypes. We demonstrate for the first time that there are serotypic differences in NS5 nuclear localization. Whereas the DENV-2 and -3 proteins accumulate in the nucleus, DENV-1 and -4 NS5 are predominantly if not exclusively localized to the cytoplasm. Comparative studies on the DENV-2 and -4 NS5 proteins revealed that the difference in DENV-4 NS5 nuclear localization was not due to rapid nuclear export but rather the lack of a functional nuclear localization sequence. Interaction studies using DENV-2 and -4 NS5 and human importin-α isoforms failed to identify an interaction that supported the differential nuclear localization of NS5. siRNA knockdown of the human importin-α isoform KPNA2, corresponding to the murine importin-α isoform previously shown to bind to DENV-2 NS5, did not substantially affect DENV-2 NS5 nuclear localization, whereas knockdown of importin-β did. The serotypic differences in NS5 nuclear localization did not correlate with differences in IL-8 gene expression. The results show that NS5 nuclear localization is not strictly required for virus replication but is more likely to have an auxiliary function in the life cycle of specific DENV serotypes.
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Affiliation(s)
- Holger Hannemann
- School of Cellular and Molecular Medicine, Faculty of Medical and Veterinary Sciences, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
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