1
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Layish B, Goli R, Flick H, Huang SW, Zhang RZ, Kvaratskhelia M, Kane M. Virus specificity and nucleoporin requirements for MX2 activity are affected by GTPase function and capsid-CypA interactions. PLoS Pathog 2024; 20:e1011830. [PMID: 38512975 PMCID: PMC10986937 DOI: 10.1371/journal.ppat.1011830] [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: 11/15/2023] [Revised: 04/02/2024] [Accepted: 02/29/2024] [Indexed: 03/23/2024] Open
Abstract
Human myxovirus resistance 2 (MX2/MXB) is an interferon-induced GTPase that inhibits human immunodeficiency virus-1 (HIV-1) infection by preventing nuclear import of the viral preintegration complex. The HIV-1 capsid (CA) is the major viral determinant for sensitivity to MX2, and complex interactions between MX2, CA, nucleoporins (Nups), cyclophilin A (CypA), and other cellular proteins influence the outcome of viral infection. To explore the interactions between MX2, the viral CA, and CypA, we utilized a CRISPR-Cas9/AAV approach to generate CypA knock-out cell lines as well as cells that express CypA from its endogenous locus, but with specific point mutations that would abrogate CA binding but should not affect enzymatic activity or cellular function. We found that infection of CypA knock-out and point mutant cell lines with wild-type HIV-1 and CA mutants recapitulated the phenotypes observed upon cyclosporine A (CsA) addition, indicating that effects of CsA treatment are the direct result of blocking CA-CypA interactions and are therefore independent from potential interactions between CypA and MX2 or other cellular proteins. Notably, abrogation of GTP hydrolysis by MX2 conferred enhanced antiviral activity when CA-CypA interactions were abolished, and this effect was not mediated by the CA-binding residues in the GTPase domain, or by phosphorylation of MX2 at position T151. We additionally found that elimination of GTPase activity also altered the Nup requirements for MX2 activity. Our data demonstrate that the antiviral activity of MX2 is affected by CypA-CA interactions in a virus-specific and GTPase activity-dependent manner. These findings further highlight the importance of the GTPase domain of MX2 in regulation of substrate specificity and interaction with nucleocytoplasmic trafficking pathways.
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Affiliation(s)
- Bailey Layish
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Ram Goli
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Haley Flick
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Szu-Wei Huang
- Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Robert Z. Zhang
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Mamuka Kvaratskhelia
- Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Melissa Kane
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
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2
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Layish B, Goli R, Flick H, Huang SW, Zhang RZ, Kvaratskhelia M, Kane M. Virus specificity and nucleoporin requirements for MX2 activity are affected by GTPase function and capsid-CypA interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.16.567336. [PMID: 38014352 PMCID: PMC10680775 DOI: 10.1101/2023.11.16.567336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Human myxovirus resistance 2 (MX2/MXB) is an interferon-induced GTPase that inhibits human immunodeficiency virus-1 (HIV-1) infection by preventing nuclear import of the viral preintegration complex. The HIV-1 capsid (CA) is the major viral determinant for sensitivity to MX2, and complex interactions between MX2, CA, nucleoporins (Nups), cyclophilin A (CypA), and other cellular proteins influence the outcome of viral infection. To explore the interactions between MX2, the viral CA, and CypA, we utilized a CRISPR-Cas9/AAV approach to generate CypA knock-out cell lines as well as cells that express CypA from its endogenous locus, but with specific point mutations that would abrogate CA binding but should not affect enzymatic activity or cellular function. We found that infection of CypA knock-out and point mutant cell lines with wild-type HIV-1 and CA mutants recapitulated the phenotypes observed upon cyclosporine A (CsA) addition, indicating that effects of CsA treatment are the direct result of blocking CA-CypA interactions and are therefore independent from potential interactions between CypA and MX2 or other cellular proteins. Notably, abrogation of GTP hydrolysis by MX2 conferred enhanced antiviral activity when CA-CypA interactions were abolished, and this effect was not mediated by the CA-binding residues in the GTPase domain, or by phosphorylation of MX2 at position T151. We additionally found that elimination of GTPase activity also altered the Nup requirements for MX2 activity. Our data demonstrate that the antiviral activity of MX2 is affected by CypA-CA interactions in a virus-specific and GTPase activity-dependent manner. These findings further highlight the importance of the GTPase domain of MX2 in regulation of substrate specificity and interaction with nucleocytoplasmic trafficking pathways.
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Affiliation(s)
- Bailey Layish
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Ram Goli
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Haley Flick
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Szu-Wei Huang
- Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Robert Z Zhang
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Mamuka Kvaratskhelia
- Division of Infectious Diseases, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Melissa Kane
- Department of Pediatrics, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
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3
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Poyatos-García J, Blázquez-Bernal Á, Selva-Giménez M, Bargiela A, Espinosa-Espinosa J, Vázquez-Manrique RP, Bigot A, Artero R, Vilchez JJ. CRISPR-Cas9 editing of a TNPO3 mutation in a muscle cell model of limb-girdle muscular dystrophy type D2. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 31:324-338. [PMID: 36789274 PMCID: PMC9898580 DOI: 10.1016/j.omtn.2023.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 01/06/2023] [Indexed: 01/13/2023]
Abstract
A single-nucleotide deletion in the stop codon of the nuclear import receptor transportin-3 (TNPO3), also involved in human immunodeficiency virus type 1 (HIV-1) infection, causes the ultrarare autosomal dominant disease limb-girdle muscular dystrophy D2 (LGMDD2) by extending the wild-type protein. Here, we generated a patient-derived in vitro model of LGMDD2 as an immortalized myoblast cell line carrying the TNP O 3 mutation. The cell model reproduced critical molecular alterations seen in patients, such as TNP O 3 overexpression, defects in terminal muscle markers, and autophagy overactivation. Correction of the TNP O 3 mutation via CRISPR-Cas9 editing caused a significant reversion of the pathological phenotypes in edited cells, including a complete absence of the mutant TNPO3 protein, as detected with a polyclonal antibody specific against the abnormal 15-aa peptide. Transcriptomic analyses found that 15% of the transcriptome was differentially expressed in model myotubes. CRISPR-Cas9-corrected cells showed that 44% of the alterations were rescued toward normal levels. MicroRNAs (miRNAs) analyses showed that around 50% of miRNAs with impaired expression because of the disease were recovered on the mutation edition. In summary, this work provides proof of concept of the potential of CRISPR-Cas9-mediated gene editing of TNP O 3 as a therapeutic approach and describes critical reagents in LGMDD2 research.
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Affiliation(s)
- Javier Poyatos-García
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), U763, CB06/05/0091, 46026 Valencia, Spain
- Neuromuscular and Ataxias Research Group, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain
| | - Águeda Blázquez-Bernal
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Burjasot, 46100 Valencia, Spain
- INCLIVA Biomedical Research Institute, 46010 Valencia, Spain
| | - Marta Selva-Giménez
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), U763, CB06/05/0091, 46026 Valencia, Spain
- Neuromuscular and Ataxias Research Group, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain
| | - Ariadna Bargiela
- Neuromuscular and Ataxias Research Group, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain
| | - Jorge Espinosa-Espinosa
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Burjasot, 46100 Valencia, Spain
- INCLIVA Biomedical Research Institute, 46010 Valencia, Spain
| | - Rafael P. Vázquez-Manrique
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), U763, CB06/05/0091, 46026 Valencia, Spain
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain
- Joint Unit for Rare Diseases IIS La Fe-CIPF, 46012 Valencia, Spain
| | - Anne Bigot
- Sorbonne Université, INSERM, Institut de Myologie, Centre de Recherche en Myologie, 75013 Paris, France
| | - Ruben Artero
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Burjasot, 46100 Valencia, Spain
- INCLIVA Biomedical Research Institute, 46010 Valencia, Spain
| | - Juan Jesús Vilchez
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), U763, CB06/05/0091, 46026 Valencia, Spain
- Neuromuscular and Ataxias Research Group, Health Research Institute Hospital La Fe (IIS La Fe), 46026 Valencia, Spain
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4
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Eilers G, Gupta K, Allen A, Montermoso S, Murali H, Sharp R, Hwang Y, Bushman FD, Van Duyne G. Structure of a HIV-1 IN-Allosteric inhibitor complex at 2.93 Å resolution: Routes to inhibitor optimization. PLoS Pathog 2023; 19:e1011097. [PMID: 36867659 PMCID: PMC10016701 DOI: 10.1371/journal.ppat.1011097] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 03/15/2023] [Accepted: 01/03/2023] [Indexed: 03/04/2023] Open
Abstract
HIV integrase (IN) inserts viral DNA into the host genome and is the target of the strand transfer inhibitors (STIs), a class of small molecules currently in clinical use. Another potent class of antivirals is the allosteric inhibitors of integrase, or ALLINIs. ALLINIs promote IN aggregation by stabilizing an interaction between the catalytic core domain (CCD) and carboxy-terminal domain (CTD) that undermines viral particle formation in late replication. Ongoing challenges with inhibitor potency, toxicity, and viral resistance motivate research to understand their mechanism. Here, we report a 2.93 Å X-ray crystal structure of the minimal ternary complex between CCD, CTD, and the ALLINI BI-224436. This structure reveals an asymmetric ternary complex with a prominent network of π-mediated interactions that suggest specific avenues for future ALLINI development and optimization.
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Affiliation(s)
- Grant Eilers
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kushol Gupta
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Audrey Allen
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Saira Montermoso
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Hemma Murali
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Robert Sharp
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Young Hwang
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Frederic D. Bushman
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Gregory Van Duyne
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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5
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Complex Relationships between HIV-1 Integrase and Its Cellular Partners. Int J Mol Sci 2022; 23:ijms232012341. [PMID: 36293197 PMCID: PMC9603942 DOI: 10.3390/ijms232012341] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/09/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022] Open
Abstract
RNA viruses, in pursuit of genome miniaturization, tend to employ cellular proteins to facilitate their replication. HIV-1, one of the most well-studied retroviruses, is not an exception. There is numerous evidence that the exploitation of cellular machinery relies on nucleic acid-protein and protein-protein interactions. Apart from Vpr, Vif, and Nef proteins that are known to regulate cellular functioning via interaction with cell components, another viral protein, integrase, appears to be crucial for proper virus-cell dialog at different stages of the viral life cycle. The goal of this review is to summarize and systematize existing data on known cellular partners of HIV-1 integrase and their role in the HIV-1 life cycle.
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6
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Rocchi C, Gouet P, Parissi V, Fiorini F. The C-Terminal Domain of HIV-1 Integrase: A Swiss Army Knife for the Virus? Viruses 2022; 14:v14071397. [PMID: 35891378 PMCID: PMC9316232 DOI: 10.3390/v14071397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/22/2022] [Accepted: 06/22/2022] [Indexed: 12/31/2022] Open
Abstract
Retroviral integrase is a multimeric enzyme that catalyzes the integration of reverse-transcribed viral DNA into the cellular genome. Beyond integration, the Human immunodeficiency virus type 1 (HIV-1) integrase is also involved in many other steps of the viral life cycle, such as reverse transcription, nuclear import, virion morphogenesis and proviral transcription. All these additional functions seem to depend on the action of the integrase C-terminal domain (CTD) that works as a molecular hub, interacting with many different viral and cellular partners. In this review, we discuss structural issues concerning the CTD, with particular attention paid to its interaction with nucleic acids. We also provide a detailed map of post-translational modifications and interaction with molecular partners.
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Affiliation(s)
- Cecilia Rocchi
- Molecular Microbiology and Structural Biochemistry (MMSB), CNRS, University of Lyon 1, UMR 5086, 69367 Lyon, France; (C.R.); (P.G.)
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), 33076 Bordeaux, France;
| | - Patrice Gouet
- Molecular Microbiology and Structural Biochemistry (MMSB), CNRS, University of Lyon 1, UMR 5086, 69367 Lyon, France; (C.R.); (P.G.)
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), 33076 Bordeaux, France;
| | - Vincent Parissi
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), 33076 Bordeaux, France;
- Fundamental Microbiology and Pathogenicity (MFP), CNRS, University of Bordeaux, UMR5234, 33405 Bordeaux, France
| | - Francesca Fiorini
- Molecular Microbiology and Structural Biochemistry (MMSB), CNRS, University of Lyon 1, UMR 5086, 69367 Lyon, France; (C.R.); (P.G.)
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), 33076 Bordeaux, France;
- Correspondence: ; Tel.: +33-4-72722624; Fax: +33-4-72722616
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7
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Diez-Fuertes F, López-Huertas MR, García-Pérez J, Calonge E, Bermejo M, Mateos E, Martí P, Muelas N, Vílchez JJ, Coiras M, Alcamí J, Rodríguez-Mora S. Transcriptomic Evidence of the Immune Response Activation in Individuals With Limb Girdle Muscular Dystrophy Dominant 2 (LGMDD2) Contributes to Resistance to HIV-1 Infection. Front Cell Dev Biol 2022; 10:839813. [PMID: 35646913 PMCID: PMC9136291 DOI: 10.3389/fcell.2022.839813] [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: 12/20/2021] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
LGMDD2 is a rare form of muscular dystrophy characterized by one of the three heterozygous deletions described within the TNPO3 gene that result in the addition of a 15-amino acid tail in the C-terminus.TNPO3 is involved in the nuclear import of splicing factors and acts as a host cofactor for HIV-1 infection by mechanisms not yet deciphered. Further characterization of the crosstalk between HIV-1 infection and LGMDD2 disease may contribute to a better understanding of both the cellular alterations occurring in LGMDD2 patients and the role of TNPO3 in the HIV-1 cycle. To this regard, transcriptome profiling of PBMCs from LGMDD2 patients carrying the deletion c.2771delA in the TNPO3 gene was compared to healthy controls. A total of 545 differentially expressed genes were detected between LGMDD2 patients and healthy controls, with a high representation of G protein-coupled receptor binding chemokines and metallopeptidases among the most upregulated genes in LGMDD2 patients. Plasma levels of IFN-β and IFN-γ were 4.7- and 2.7-fold higher in LGMDD2 patients, respectively. An increase of 2.3-fold in the expression of the interferon-stimulated gene MxA was observed in activated PBMCs from LGMDD2 patients after ex vivo HIV-1 pseudovirus infection. Thus, the analysis suggests a pro-inflammatory state in LGMDD2 patients also described for other muscular dystrophies, that is characterized by the alteration of IL-17 signaling pathway and the consequent increase of metallopeptidases activity and TNF response. In summary, the increase in interferons and inflammatory mediators suggests an antiviral environment and resistance to HIV-1 infection but that could also impair muscular function in LGMDD2 patients, worsening disease evolution. Biomarkers of disease progression and therapeutic strategies based on these genes and mechanisms should be further investigated for this type of muscular dystrophy.
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Affiliation(s)
- Francisco Diez-Fuertes
- AIDS Immunopathogenesis Unit, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - María Rosa López-Huertas
- AIDS Immunopathogenesis Unit, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Javier García-Pérez
- AIDS Immunopathogenesis Unit, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Esther Calonge
- AIDS Immunopathogenesis Unit, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Mercedes Bermejo
- AIDS Immunopathogenesis Unit, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Elena Mateos
- AIDS Immunopathogenesis Unit, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Pilar Martí
- Neuromuscular Diseases Unit, Neurology Department, Hospital Universitari i Politècnic La Fe, Valencia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Nuria Muelas
- Neuromuscular Diseases Unit, Neurology Department, Hospital Universitari i Politècnic La Fe, Valencia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Juan Jesús Vílchez
- Neuromuscular Diseases Unit, Neurology Department, Hospital Universitari i Politècnic La Fe, Valencia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Mayte Coiras
- AIDS Immunopathogenesis Unit, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - José Alcamí
- AIDS Immunopathogenesis Unit, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
- Infectious Diseases Unit, IDIBAPS, Hospital Clinic, University of Barcelona, Barcelona, Spain
- *Correspondence: José Alcamí, ; Sara Rodríguez-Mora,
| | - Sara Rodríguez-Mora
- AIDS Immunopathogenesis Unit, National Center of Microbiology, Instituto de Salud Carlos III, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
- *Correspondence: José Alcamí, ; Sara Rodríguez-Mora,
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8
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Costa R, Rodia MT, Pacilio S, Angelini C, Cenacchi G. LGMD D2 TNPO3-Related: From Clinical Spectrum to Pathogenetic Mechanism. Front Neurol 2022; 13:840683. [PMID: 35309568 PMCID: PMC8931187 DOI: 10.3389/fneur.2022.840683] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Limb-girdle muscular dystrophies (LGMDs) are clinically and genetically heterogeneous diseases presenting with a wide clinical spectrum. Autosomal dominant LGMDs represent about 10–15% of LGMDs and include disorders due to defects of DNAJB6, transportin-3 (TNPO3), HNRNPDL, Calpain-3 (CAPN3), and Bethlem myopathy. This review article aims to describe the clinical spectrum of LGMD D2 TNPO3-related, a rare disease due to heterozygous mutation in the TNPO3 gene. TNPO3 encodes for transportin-3, which belongs to the importin beta family and transports into the nucleus serine/arginine-rich (SR) proteins, such as splicing factors, and HIV-1 proteins, thus contributing to viral infection. The purpose of this review is to present and compare the clinical features and the genetic and histopathological findings described in LGMD D2, performing a comparative analytical description of all the families and sporadic cases identified. Even if the causative gene and mutations of this disease have been identified, the pathogenic mechanisms are still an open issue; therefore, we will present an overview of the hypotheses that explain the pathology of LGMD D2 TNPO3-related.
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Affiliation(s)
- Roberta Costa
- Department of Biomedical and Neuromotor Sciences–DIBINEM, Alma Mater Studiorum University of Bologna, Bologna, Italy
- Applied Biomedical Research Center–CRBA, IRCCS St. Orsola Hospital, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Maria Teresa Rodia
- Department of Biomedical and Neuromotor Sciences–DIBINEM, Alma Mater Studiorum University of Bologna, Bologna, Italy
- Applied Biomedical Research Center–CRBA, IRCCS St. Orsola Hospital, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Serafina Pacilio
- Department of Biomedical and Neuromotor Sciences–DIBINEM, Alma Mater Studiorum University of Bologna, Bologna, Italy
- Applied Biomedical Research Center–CRBA, IRCCS St. Orsola Hospital, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Corrado Angelini
- Laboratory for Neuromuscular Diseases, Campus Pietro d'Abano, University of Padova, Padova, Italy
| | - Giovanna Cenacchi
- Department of Biomedical and Neuromotor Sciences–DIBINEM, Alma Mater Studiorum University of Bologna, Bologna, Italy
- Applied Biomedical Research Center–CRBA, IRCCS St. Orsola Hospital, Alma Mater Studiorum University of Bologna, Bologna, Italy
- *Correspondence: Giovanna Cenacchi
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9
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Shen Q, Wu C, Freniere C, Tripler TN, Xiong Y. Nuclear Import of HIV-1. Viruses 2021; 13:2242. [PMID: 34835048 PMCID: PMC8619967 DOI: 10.3390/v13112242] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/26/2021] [Accepted: 11/01/2021] [Indexed: 12/12/2022] Open
Abstract
The delivery of the HIV-1 genome into the nucleus is an indispensable step in retroviral infection of non-dividing cells, but the mechanism of HIV-1 nuclear import has been a longstanding debate due to controversial experimental evidence. It was commonly believed that the HIV-1 capsid would need to disassemble (uncoat) in the cytosol before nuclear import because the capsid is larger than the central channel of nuclear pore complexes (NPCs); however, increasing evidence demonstrates that intact, or nearly intact, HIV-1 capsid passes through the NPC to enter the nucleus. With the protection of the capsid, the HIV-1 core completes reverse transcription in the nucleus and is translocated to the integration site. Uncoating occurs while, or after, the viral genome is released near the integration site. These independent discoveries reveal a compelling new paradigm of this important step of the HIV-1 life cycle. In this review, we summarize the recent studies related to HIV-1 nuclear import, highlighting the spatial-temporal relationship between the nuclear entry of the virus core, reverse transcription, and capsid uncoating.
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Affiliation(s)
| | | | | | | | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA; (Q.S.); (C.W.); (C.F.); (T.N.T.)
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10
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Abstract
To infect nondividing cells, HIV-1 needs to cross the nuclear membrane. The importin transportin-SR2 (TRN-SR2 or transportin-3) has been proposed to mediate HIV-1 nuclear import, but the detailed mechanism remains unresolved. The direct interaction of TRN-SR2 with HIV-1 integrase (IN) has been proposed to drive HIV-1 nuclear import. Alternatively, TRN-SR2 may play an indirect role by mediating nuclear import of cleavage and polyadenylation specificity factor 6 (CPSF6). To unravel the role of TRN-SR2, we designed CRISPR/Cas9 guide RNAs targeting different exons of TNPO3. Although this approach failed to generate full knockouts, monoallelic knockout clones were generated with indel mutations. HIV-1 replication was hampered in those clones at the level of HIV-1 nuclear import without an effect on the cellular distribution of the TRN-SR2 cargoes CPSF6 or alternative splicing factor1/pre-mRNA splicing factor SF2 (ASF/SF2). Recombinant ΔV105 TRN-SR2 expressed in clone 15.15 was 2-fold impaired for interaction with HIV-1 IN and classified as an interaction mutant. Our data support a model whereby TRN-SR2 acts as a cofactor of HIV-1 nuclear import without compromising the nuclear import of cellular cargoes. CRISPR/Cas9-induced mutagenesis can be used as a method to generate interface mutants to characterize host factors of human pathogens. IMPORTANCE Combination antiretroviral therapy (cART) effectively controls HIV-1 by reducing viral loads, but it does not cure the infection. Lifelong treatment with cART is a prerequisite for sustained viral suppression. The rapid emergence of drug-resistant viral strains drives the necessity to discover new therapeutic targets. The nuclear import of HIV-1 is crucial in the HIV-1 replication cycle, but the detailed mechanism remains incompletely understood. This study provides evidence that TRN-SR2 directly mediates HIV-1 nuclear import via the interaction with HIV-1 integrase. The interaction between those proteins is therefore a promising target toward a rational drug design which could lead to new therapeutic strategies due to the bottleneck nature of HIV-1 nuclear import.
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11
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Tavares LA, Januário YC, daSilva LLP. HIV-1 Hijacking of Host ATPases and GTPases That Control Protein Trafficking. Front Cell Dev Biol 2021; 9:622610. [PMID: 34307340 PMCID: PMC8295591 DOI: 10.3389/fcell.2021.622610] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 06/07/2021] [Indexed: 12/22/2022] Open
Abstract
The human immunodeficiency virus (HIV-1) modifies the host cell environment to ensure efficient and sustained viral replication. Key to these processes is the capacity of the virus to hijack ATPases, GTPases and the associated proteins that control intracellular protein trafficking. The functions of these energy-harnessing enzymes can be seized by HIV-1 to allow the intracellular transport of viral components within the host cell or to change the subcellular distribution of antiviral factors, leading to immune evasion. Here, we summarize how energy-related proteins deviate from their normal functions in host protein trafficking to aid the virus in different phases of its replicative cycle. Recent discoveries regarding the interplay among HIV-1 and host ATPases and GTPases may shed light on potential targets for pharmacological intervention.
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Affiliation(s)
- Lucas A Tavares
- Department of Cell and Molecular Biology, Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Yunan C Januário
- Department of Cell and Molecular Biology, Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Luis L P daSilva
- Department of Cell and Molecular Biology, Center for Virology Research, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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12
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AlBurtamani N, Paul A, Fassati A. The Role of Capsid in the Early Steps of HIV-1 Infection: New Insights into the Core of the Matter. Viruses 2021; 13:v13061161. [PMID: 34204384 PMCID: PMC8234406 DOI: 10.3390/v13061161] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/10/2021] [Accepted: 06/14/2021] [Indexed: 01/27/2023] Open
Abstract
In recent years, major advances in research and experimental approaches have significantly increased our knowledge on the role of the HIV-1 capsid in the virus life cycle, from reverse transcription to integration and gene expression. This makes the capsid protein a good pharmacological target to inhibit HIV-1 replication. This review covers our current understanding of the role of the viral capsid in the HIV-1 life cycle and its interaction with different host factors that enable reverse transcription, trafficking towards the nucleus, nuclear import and integration into host chromosomes. It also describes different promising small molecules, some of them in clinical trials, as potential targets for HIV-1 therapy.
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13
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Tabasi M, Nombela I, Janssens J, Lahousse AP, Christ F, Debyser Z. Role of Transportin-SR2 in HIV-1 Nuclear Import. Viruses 2021; 13:829. [PMID: 34064404 PMCID: PMC8147801 DOI: 10.3390/v13050829] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/29/2021] [Accepted: 05/02/2021] [Indexed: 12/14/2022] Open
Abstract
The HIV replication cycle depends on the interaction of viral proteins with proteins of the host. Unraveling host-pathogen interactions during the infection is of great importance for understanding the pathogenesis and the development of antiviral therapies. To date HIV uncoating and nuclear import are the most debated steps of the HIV-1 replication cycle. Despite numerous studies during past decades, there is still much controversy with respect to the identity and the role of viral and host factors involved in these processes. In this review, we provide a comprehensive overview on the role of transportin-SR2 as a host cell factor during active nuclear transport.
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Affiliation(s)
| | | | | | | | | | - Zeger Debyser
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Flanders, Belgium; (M.T.); (I.N.); (J.J.); (A.P.L.); (F.C.)
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14
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Gupta K, Allen A, Giraldo C, Eilers G, Sharp R, Hwang Y, Murali H, Cruz K, Janmey P, Bushman F, Van Duyne GD. Allosteric HIV Integrase Inhibitors Promote Formation of Inactive Branched Polymers via Homomeric Carboxy-Terminal Domain Interactions. Structure 2021; 29:213-225.e5. [PMID: 33357410 PMCID: PMC7935764 DOI: 10.1016/j.str.2020.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/04/2020] [Accepted: 12/04/2020] [Indexed: 12/12/2022]
Abstract
The major effect of allosteric HIV integrase (IN) inhibitors (ALLINIs) is observed during virion maturation, where ALLINI treatment interrupts IN-RNA interactions via drug-induced IN aggregation, leading to the formation of aberrant virions. To understand the structural changes that accompany drug-induced aggregation, we determined the soft matter properties of ALLINI-induced IN aggregates. Using small-angle neutron scattering, SEM, and rheology, we have discovered that the higher-order aggregates induced by ALLINIs have the characteristics of weak three-dimensional gels with a fractal-like character. Their formation is inhibited by the host factor LEDGF/p75, as well as ex vivo resistance substitutions. Mutagenesis and biophysical analyses reveal that homomeric carboxy-terminal domain interactions are required to achieve the branched-polymer nature of the ALLINI-induced aggregates. These studies provide key insight into the mechanisms of ALLINI action and resistance in the context of the crowded virion environment where ALLINIs exert their effect.
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Affiliation(s)
- Kushol Gupta
- Department of Biochemistry & Biophysics, Perelman School of Medicine, University of Pennsylvania, 809C Stellar-Chance Building, 422 Curie Boulevard, Philadelphia, PA 19105-6059, USA
| | - Audrey Allen
- Department of Microbiology, University of Pennsylvania School of Medicine, 426 Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104-6076, USA
| | - Carolina Giraldo
- Department of Biochemistry & Biophysics, Perelman School of Medicine, University of Pennsylvania, 809C Stellar-Chance Building, 422 Curie Boulevard, Philadelphia, PA 19105-6059, USA
| | - Grant Eilers
- Department of Microbiology, University of Pennsylvania School of Medicine, 426 Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104-6076, USA
| | - Robert Sharp
- Department of Biochemistry & Biophysics, Perelman School of Medicine, University of Pennsylvania, 809C Stellar-Chance Building, 422 Curie Boulevard, Philadelphia, PA 19105-6059, USA
| | - Young Hwang
- Department of Microbiology, University of Pennsylvania School of Medicine, 426 Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104-6076, USA
| | - Hemma Murali
- Department of Biochemistry & Biophysics, Perelman School of Medicine, University of Pennsylvania, 809C Stellar-Chance Building, 422 Curie Boulevard, Philadelphia, PA 19105-6059, USA
| | - Katrina Cruz
- Department of Physiology, and Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104-6383, USA
| | - Paul Janmey
- Department of Physiology, and Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104-6383, USA
| | - Frederic Bushman
- Department of Microbiology, University of Pennsylvania School of Medicine, 426 Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104-6076, USA.
| | - Gregory D Van Duyne
- Department of Biochemistry & Biophysics, Perelman School of Medicine, University of Pennsylvania, 809C Stellar-Chance Building, 422 Curie Boulevard, Philadelphia, PA 19105-6059, USA.
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15
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Structure, Function, and Interactions of the HIV-1 Capsid Protein. Life (Basel) 2021; 11:life11020100. [PMID: 33572761 PMCID: PMC7910843 DOI: 10.3390/life11020100] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 11/30/2022] Open
Abstract
The capsid (CA) protein of the human immunodeficiency virus type 1 (HIV-1) is an essential structural component of a virion and facilitates many crucial life cycle steps through interactions with host cell factors. Capsid shields the reverse transcription complex from restriction factors while it enables trafficking to the nucleus by hijacking various adaptor proteins, such as FEZ1 and BICD2. In addition, the capsid facilitates the import and localization of the viral complex in the nucleus through interaction with NUP153, NUP358, TNPO3, and CPSF-6. In the later stages of the HIV-1 life cycle, CA plays an essential role in the maturation step as a constituent of the Gag polyprotein. In the final phase of maturation, Gag is cleaved, and CA is released, allowing for the assembly of CA into a fullerene cone, known as the capsid core. The fullerene cone consists of ~250 CA hexamers and 12 CA pentamers and encloses the viral genome and other essential viral proteins for the next round of infection. As research continues to elucidate the role of CA in the HIV-1 life cycle and the importance of the capsid protein becomes more apparent, CA displays potential as a therapeutic target for the development of HIV-1 inhibitors.
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16
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NKNK: a New Essential Motif in the C-Terminal Domain of HIV-1 Group M Integrases. J Virol 2020; 94:JVI.01035-20. [PMID: 32727879 DOI: 10.1128/jvi.01035-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/17/2020] [Indexed: 11/20/2022] Open
Abstract
Using coevolution network interference based on comparison of two phylogenetically distantly related isolates, one from the main group M and the other from the minor group O of HIV-1, we identify, in the C-terminal domain (CTD) of integrase, a new functional motif constituted by four noncontiguous amino acids (N222K240N254K273). Mutating the lysines abolishes integration through decreased 3' processing and inefficient nuclear import of reverse-transcribed genomes. Solution of the crystal structures of wild-type (wt) and mutated CTDs shows that the motif generates a positive surface potential that is important for integration. The number of charges in the motif appears more crucial than their position within the motif. Indeed, the positions of the K's could be permutated or additional K's could be inserted in the motif, generally without affecting integration per se Despite this potential genetic flexibility, the NKNK arrangement is strictly conserved in natural sequences, indicative of an effective purifying selection exerted at steps other than integration. Accordingly, reverse transcription was reduced even in the mutants that retained wt integration levels, indicating that specifically the wt sequence is optimal for carrying out the multiple functions that integrase exerts. We propose that the existence of several amino acid arrangements within the motif, with comparable efficiencies of integration per se, might have constituted an asset for the acquisition of additional functions during viral evolution.IMPORTANCE Intensive studies of HIV-1 have revealed its extraordinary ability to adapt to environmental and immunological challenges, an ability that is also at the basis of antiviral treatment escape. Here, by deconvoluting the different roles of the viral integrase in the various steps of the infectious cycle, we report how the existence of alternative equally efficient structural arrangements for carrying out one function opens up the possibility of adapting to the optimization of further functionalities exerted by the same protein. Such a property provides an asset to increase the efficiency of the infectious process. On the other hand, though, the identification of this new motif provides a potential target for interfering simultaneously with multiple functions of the protein.
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17
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TNPO3-Mediated Nuclear Entry of the Rous Sarcoma Virus Gag Protein Is Independent of the Cargo-Binding Domain. J Virol 2020; 94:JVI.00640-20. [PMID: 32581109 DOI: 10.1128/jvi.00640-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 06/16/2020] [Indexed: 11/20/2022] Open
Abstract
Retroviral Gag polyproteins orchestrate the assembly and release of nascent virus particles from the plasma membranes of infected cells. Although it was traditionally thought that Gag proteins trafficked directly from the cytosol to the plasma membrane, we discovered that the oncogenic avian alpharetrovirus Rous sarcoma virus (RSV) Gag protein undergoes transient nucleocytoplasmic transport as an intrinsic step in virus assembly. Using a genetic approach in yeast, we identified three karyopherins that engage the two independent nuclear localization signals (NLSs) in Gag. The primary NLS is in the nucleocapsid (NC) domain of Gag and binds directly to importin-α, which recruits importin-β to mediate nuclear entry. The second NLS (TNPO3), which resides in the matrix (MA) domain, is dependent on importin-11 and transportin-3 (TNPO3), which are known as MTR10p and Kap120p in yeast, although it is not clear whether these import factors are independent or additive. The functions of importin-α/importin-β and importin-11 have been verified in avian cells, whereas the role of TNPO3 has not been studied. In this report, we demonstrate that TNPO3 directly binds to Gag and mediates its nuclear entry. To our surprise, this interaction did not require the cargo-binding domain (CBD) of TNPO3, which typically mediates nuclear entry for other binding partners of TNPO3, including SR domain-containing splicing factors and tRNAs that reenter the nucleus. These results suggest that RSV hijacks this host nuclear import pathway using a unique mechanism, potentially allowing other cargo to simultaneously bind TNPO3.IMPORTANCE RSV Gag nuclear entry is facilitated using three distinct host import factors that interact with nuclear localization signals in the Gag MA and NC domains. Here, we show that the MA region is required for nuclear import of Gag through the TNPO3 pathway. Gag nuclear entry does not require the CBD of TNPO3. Understanding the molecular basis for TNPO3-mediated nuclear trafficking of the RSV Gag protein may lead to a deeper appreciation for whether different import factors play distinct roles in retrovirus replication.
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18
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The mutation of Transportin 3 gene that causes limb girdle muscular dystrophy 1F induces protection against HIV-1 infection. PLoS Pathog 2019; 15:e1007958. [PMID: 31465518 PMCID: PMC6715175 DOI: 10.1371/journal.ppat.1007958] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 07/03/2019] [Indexed: 01/10/2023] Open
Abstract
The causative mutation responsible for limb girdle muscular dystrophy 1F (LGMD1F) is one heterozygous single nucleotide deletion in the stop codon of the nuclear import factor Transportin 3 gene (TNPO3). This mutation causes a carboxy-terminal extension of 15 amino acids, producing a protein of unknown function (TNPO3_mut) that is co-expressed with wild-type TNPO3 (TNPO3_wt). TNPO3 has been involved in the nuclear transport of serine/arginine-rich proteins such as splicing factors and also in HIV-1 infection through interaction with the viral integrase and capsid. We analyzed the effect of TNPO3_mut on HIV-1 infection using PBMCs from patients with LGMD1F infected ex vivo. HIV-1 infection was drastically impaired in these cells and viral integration was reduced 16-fold. No significant effects on viral reverse transcription and episomal 2-LTR circles were observed suggesting that the integration of HIV-1 genome was restricted. This is the second genetic defect described after CCR5Δ32 that shows strong resistance against HIV-1 infection.
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19
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Angelini C, Pegoraro V, Cenacchi G. The clinical and molecular spectrum of autosomal dominant limb-girdle muscular dystrophies focusing on transportinopathy. Expert Opin Orphan Drugs 2019. [DOI: 10.1080/21678707.2019.1622412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
| | | | - Giovanna Cenacchi
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum–University of Bologna, Bologna, Italy
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20
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Koneru PC, Francis AC, Deng N, Rebensburg SV, Hoyte AC, Lindenberger J, Adu-Ampratwum D, Larue RC, Wempe MF, Engelman AN, Lyumkis D, Fuchs JR, Levy RM, Melikyan GB, Kvaratskhelia M. HIV-1 integrase tetramers are the antiviral target of pyridine-based allosteric integrase inhibitors. eLife 2019; 8:46344. [PMID: 31120420 PMCID: PMC6581505 DOI: 10.7554/elife.46344] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 05/22/2019] [Indexed: 12/13/2022] Open
Abstract
Allosteric HIV-1 integrase (IN) inhibitors (ALLINIs) are a promising new class of antiretroviral agents that disrupt proper viral maturation by inducing hyper-multimerization of IN. Here we show that lead pyridine-based ALLINI KF116 exhibits striking selectivity for IN tetramers versus lower order protein oligomers. IN structural features that are essential for its functional tetramerization and HIV-1 replication are also critically important for KF116 mediated higher-order IN multimerization. Live cell imaging of single viral particles revealed that KF116 treatment during virion production compromises the tight association of IN with capsid cores during subsequent infection of target cells. We have synthesized the highly active (-)-KF116 enantiomer, which displayed EC50 of ~7 nM against wild type HIV-1 and ~10 fold higher, sub-nM activity against a clinically relevant dolutegravir resistant mutant virus suggesting potential clinical benefits for complementing dolutegravir therapy with pyridine-based ALLINIs. HIV-1 inserts its genetic code into human genomes, turning healthy cells into virus factories. To do this, the virus uses an enzyme called integrase. Front-line treatments against HIV-1 called “integrase strand-transfer inhibitors” stop this enzyme from working. These inhibitors have helped to revolutionize the treatment of HIV/AIDS by protecting the cells from new infections. But, the emergence of drug resistance remains a serious problem. As the virus evolves, it changes the shape of its integrase protein, substantially reducing the effectiveness of the current therapies. One way to overcome this problem is to develop other therapies that can kill the drug resistant viruses by targeting different parts of the integrase protein. It should be much harder for the virus to evolve the right combination of changes to escape two or more treatments at once. A promising class of new compounds are “allosteric integrase inhibitors”. These chemical compounds target a part of the integrase enzyme that the other treatments do not yet reach. Rather than stopping the integrase enzyme from inserting the viral code into the human genome, the new inhibitors make integrase proteins clump together and prevent the formation of infectious viruses. At the moment, these compounds are still experimental. Before they are ready for use in people, researchers need to better understand how they work, and there are several open questions to answer. Integrase proteins work in groups of four and it is not clear how the new compounds make the integrases form large clumps, or what this does to the virus. Understanding this should allow scientists to develop improved versions of the drugs. To answer these questions, Koneru et al. first examined two of the new compounds. A combination of molecular analysis and computer modelling revealed how they work. The compounds link many separate groups of four integrases with each other to form larger and larger clumps, essentially a snowball effect. Live images of infected cells showed that the clumps of integrase get stuck outside of the virus’s protective casing. This leaves them exposed, allowing the cell to destroy the integrase enzymes. Koneru et al. also made a new compound, called (-)-KF116. Not only was this compound able to tackle normal HIV-1, it could block viruses resistant to the other type of integrase treatment. In fact, in laboratory tests, it was 10 times more powerful against these resistant viruses. Together, these findings help to explain how allosteric integrase inhibitors work, taking scientists a step closer to bringing them into the clinic. In the future, new versions of the compounds, like (-)-KF116, could help to tackle drug resistance in HIV-1.
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Affiliation(s)
- Pratibha C Koneru
- Division of Infectious Diseases, School of Medicine, University of Colorado, Aurora, United States
| | - Ashwanth C Francis
- Division of Infectious Diseases, Department of Pediatrics, Emory University, Atlanta, United States
| | - Nanjie Deng
- Department of Chemistry and Physical Sciences, Pace University, New York, United States
| | - Stephanie V Rebensburg
- Division of Infectious Diseases, School of Medicine, University of Colorado, Aurora, United States
| | - Ashley C Hoyte
- Division of Infectious Diseases, School of Medicine, University of Colorado, Aurora, United States
| | - Jared Lindenberger
- Division of Infectious Diseases, School of Medicine, University of Colorado, Aurora, United States
| | | | - Ross C Larue
- College of Pharmacy, The Ohio State University, Columbus, United States
| | - Michael F Wempe
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, United States
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, United States.,Department of Medicine, Harvard Medical School, Boston, United States
| | - Dmitry Lyumkis
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, United States
| | - James R Fuchs
- College of Pharmacy, The Ohio State University, Columbus, United States
| | - Ronald M Levy
- Department of Chemistry, Temple University, Philadelphia, United States
| | - Gregory B Melikyan
- Division of Infectious Diseases, Department of Pediatrics, Emory University, Atlanta, United States
| | - Mamuka Kvaratskhelia
- Division of Infectious Diseases, School of Medicine, University of Colorado, Aurora, United States
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21
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Kane M, Rebensburg SV, Takata MA, Zang TM, Yamashita M, Kvaratskhelia M, Bieniasz PD. Nuclear pore heterogeneity influences HIV-1 infection and the antiviral activity of MX2. eLife 2018; 7:e35738. [PMID: 30084827 PMCID: PMC6101944 DOI: 10.7554/elife.35738] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 08/06/2018] [Indexed: 12/14/2022] Open
Abstract
HIV-1 accesses the nuclear DNA of interphase cells via a poorly defined process involving functional interactions between the capsid protein (CA) and nucleoporins (Nups). Here, we show that HIV-1 CA can bind multiple Nups, and that both natural and manipulated variation in Nup levels impacts HIV-1 infection in a manner that is strikingly dependent on cell-type, cell-cycle, and cyclophilin A (CypA). We also show that Nups mediate the function of the antiviral protein MX2, and that MX2 can variably inhibit non-viral NLS function. Remarkably, both enhancing and inhibiting effects of cyclophilin A and MX2 on various HIV-1 CA mutants could be induced or abolished by manipulating levels of the Nup93 subcomplex, the Nup62 subcomplex, NUP88, NUP214, RANBP2, or NUP153. Our findings suggest that several Nup-dependent 'pathways' are variably exploited by HIV-1 to target host DNA in a cell-type, cell-cycle, CypA and CA-sequence dependent manner, and are differentially inhibited by MX2.
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Affiliation(s)
- Melissa Kane
- Laboratory of RetrovirologyThe Rockefeller UniversityNew YorkUnited States
| | - Stephanie V Rebensburg
- Division of Infectious DiseasesUniversity of Colorado School of MedicineAuroraUnited States
| | - Matthew A Takata
- Laboratory of RetrovirologyThe Rockefeller UniversityNew YorkUnited States
| | - Trinity M Zang
- Laboratory of RetrovirologyThe Rockefeller UniversityNew YorkUnited States
- Howard Hughes Medical InstituteNew YorkUnited States
| | | | - Mamuka Kvaratskhelia
- Division of Infectious DiseasesUniversity of Colorado School of MedicineAuroraUnited States
| | - Paul D Bieniasz
- Laboratory of RetrovirologyThe Rockefeller UniversityNew YorkUnited States
- Howard Hughes Medical InstituteNew YorkUnited States
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22
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Demeulemeester J, Blokken J, De Houwer S, Dirix L, Klaassen H, Marchand A, Chaltin P, Christ F, Debyser Z. Inhibitors of the integrase-transportin-SR2 interaction block HIV nuclear import. Retrovirology 2018; 15:5. [PMID: 29329553 PMCID: PMC5767004 DOI: 10.1186/s12977-018-0389-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 11/20/2017] [Indexed: 12/12/2022] Open
Abstract
Background Combination antiretroviral therapy efficiently suppresses HIV replication in infected patients, transforming HIV/AIDS into a chronic disease. Viral resistance does develop however, especially under suboptimal treatment conditions such as poor adherence. As a consequence, continued exploration of novel targets is paramount to identify novel antivirals that do not suffer from cross-resistance with existing drugs. One new promising class of targets are HIV protein–cofactor interactions. Transportin-SR2 (TRN-SR2) is a β-karyopherin that was recently identified as an HIV-1 cofactor. It has been implicated in nuclear import of the viral pre-integration complex and was confirmed as a direct binding partner of HIV-1 integrase (IN). Nevertheless, consensus on its mechanism of action is yet to be reached. Results Here we describe the development and use of an AlphaScreen-based high-throughput screening cascade for small molecule inhibitors of the HIV-1 IN–TRN-SR2 interaction. False positives and nonspecific protein–protein interaction inhibitors were eliminated through different counterscreens. We identified and confirmed 2 active compound series from an initial screen of 25,608 small molecules. These compounds significantly reduced nuclear import of fluorescently labeled HIV particles. Conclusions Alphascreen-based high-throughput screening can allow the identification of compounds representing a novel class of HIV inhibitors. These results corroborate the role of the IN–TRN-SR2 interaction in nuclear import. These compounds represent the first in class small molecule inhibitors of HIV-1 nuclear import.
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Affiliation(s)
- Jonas Demeulemeester
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium.,The Francis Crick Institute, London, UK
| | - Jolien Blokken
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium
| | - Stéphanie De Houwer
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium
| | - Lieve Dirix
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium
| | - Hugo Klaassen
- Center for Innovation and Stimulation of Drug Discovery (CISTIM), Leuven, Belgium
| | - Arnaud Marchand
- Center for Innovation and Stimulation of Drug Discovery (CISTIM), Leuven, Belgium
| | - Patrick Chaltin
- Center for Innovation and Stimulation of Drug Discovery (CISTIM), Leuven, Belgium.,Center for Drug Design and Development (CD3), KU Leuven R&D, Leuven, Belgium
| | - Frauke Christ
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium
| | - Zeger Debyser
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Kapucijnenvoer 33, VCTB +5, Bus 7001, 3000, Leuven, Flanders, Belgium.
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23
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Tsirkone VG, Blokken J, De Wit F, Breemans J, De Houwer S, Debyser Z, Christ F, Strelkov SV. N-terminal half of transportin SR2 interacts with HIV integrase. J Biol Chem 2017; 292:9699-9710. [PMID: 28356354 PMCID: PMC5465493 DOI: 10.1074/jbc.m117.777029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/14/2017] [Indexed: 11/06/2022] Open
Abstract
The karyopherin transportin SR2 (TRN-SR2, TNPO3) is responsible for shuttling specific cargoes such as serine/arginine-rich splicing factors from the cytoplasm to the nucleus. This protein plays a key role in HIV infection by facilitating the nuclear import of the pre-integration complex (PIC) that contains the viral DNA as well as several cellular and HIV proteins, including the integrase. The process of nuclear import is considered to be the bottleneck of the viral replication cycle and therefore represents a promising target for anti-HIV drug design. Previous studies have demonstrated that the direct interaction between TRN-SR2 and HIV integrase predominantly involves the catalytic core domain (CCD) and the C-terminal domain (CTD) of the integrase. We aimed at providing a detailed molecular view of this interaction through a biochemical characterization of the respective protein complex. Size-exclusion chromatography was used to characterize the interaction of TRN-SR2 with a truncated variant of the HIV-1 integrase, including both the CCD and CTD. These experiments indicate that one TRN-SR2 molecule can specifically bind one CCD-CTD dimer. Next, the regions of the solenoid-like TRN-SR2 molecule that are involved in the interaction with integrase were identified using AlphaScreen binding assays, revealing that the integrase interacts with the N-terminal half of TRN-SR2 principally through the HEAT repeats 4, 10, and 11. Combining these results with small-angle X-ray scattering data for the complex of TRN-SR2 with truncated integrase, we propose a molecular model of the complex. We speculate that nuclear import of the PIC may proceed concurrently with the normal nuclear transport.
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Affiliation(s)
| | - Jolien Blokken
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
| | - Flore De Wit
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
| | | | - Stéphanie De Houwer
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
| | - Zeger Debyser
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
| | - Frauke Christ
- the Laboratory for Molecular Virology and Gene Therapy, KU Leuven, 3000 Leuven, Belgium
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24
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Thermodynamic instability of viral proteins is a pathogen-associated molecular pattern targeted by human defensins. Sci Rep 2016; 6:32499. [PMID: 27581352 PMCID: PMC5007486 DOI: 10.1038/srep32499] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 08/08/2016] [Indexed: 11/21/2022] Open
Abstract
Human defensins are innate immune defense peptides with a remarkably broad repertoire of anti-pathogen activities. In addition to modulating immune response, inflammation, and angiogenesis, disintegrating bacterial membranes, and inactivating bacterial toxins, defensins are known to intercept various viruses at different stages of their life cycles, while remaining relatively benign towards human cells and proteins. Recently we have found that human defensins inactivate proteinaceous bacterial toxins by taking advantage of their low thermodynamic stability and acting as natural “anti-chaperones”, i.e. destabilizing the native conformation of the toxins. In the present study we tested various proteins produced by several viruses (HIV-1, PFV, and TEV) and found them to be susceptible to destabilizing effects of human α-defensins HNP-1 and HD-5 and the synthetic θ-defensin RC-101, but not β-defensins hBD-1 and hBD-2 or structurally related plant-derived peptides. Defensin-induced unfolding promoted exposure of hydrophobic groups otherwise confined to the core of the viral proteins. This resulted in precipitation, an enhanced susceptibility to proteolytic cleavage, and a loss of viral protein activities. We propose, that defensins recognize and target a common and essential physico-chemical property shared by many bacterial toxins and viral proteins – the intrinsically low thermodynamic protein stability.
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25
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Li M, Tucker LD, Asara JM, Cheruiyot CK, Lu H, Wu ZJ, Newstein MC, Dooner MS, Friedman J, Lally MA, Ramratnam B. Stem-loop binding protein is a multifaceted cellular regulator of HIV-1 replication. J Clin Invest 2016; 126:3117-29. [PMID: 27454292 PMCID: PMC4966322 DOI: 10.1172/jci82360] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 05/26/2016] [Indexed: 01/12/2023] Open
Abstract
A rare subset of HIV-1-infected individuals is able to maintain plasma viral load (VL) at low levels without antiretroviral treatment. Identifying the mechanisms underlying this atypical response to infection may lead to therapeutic advances for treating HIV-1. Here, we developed a proteomic analysis to compare peripheral blood cell proteomes in 20 HIV-1-infected individuals who maintained either high or low VL with the aim of identifying host factors that impact HIV-1 replication. We determined that the levels of multiple histone proteins were markedly decreased in cohorts of individuals with high VL. This reduction was correlated with lower levels of stem-loop binding protein (SLBP), which is known to control histone metabolism. Depletion of cellular SLBP increased promoter engagement with the chromatin structures of the host gene high mobility group protein A1 (HMGA1) and viral long terminal repeat (LTR), which led to higher levels of HIV-1 genomic integration and proviral transcription. Further, we determined that TNF-α regulates expression of SLBP and observed that plasma TNF-α levels in HIV-1-infected individuals correlated directly with VL levels and inversely with cellular SLBP levels. Our findings identify SLBP as a potentially important cellular regulator of HIV-1, thereby establishing a link between histone metabolism, inflammation, and HIV-1 infection.
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Affiliation(s)
- Ming Li
- Laboratory of Retrovirology, Division of Infectious Diseases, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
- Division of Infectious Diseases, Department of Medicine, The Miriam Hospital and Rhode Island Hospital, Providence, Rhode Island, USA
| | - Lynne D. Tucker
- Laboratory of Retrovirology, Division of Infectious Diseases, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
- Division of Infectious Diseases, Department of Medicine, The Miriam Hospital and Rhode Island Hospital, Providence, Rhode Island, USA
| | - John M. Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center and Department of Medicine, and Harvard Medical School, Boston, Massachusetts, USA
| | - Collins K. Cheruiyot
- Laboratory of Retrovirology, Division of Infectious Diseases, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
- Division of Infectious Diseases, Department of Medicine, The Miriam Hospital and Rhode Island Hospital, Providence, Rhode Island, USA
| | - Huafei Lu
- Laboratory of Retrovirology, Division of Infectious Diseases, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
- Division of Infectious Diseases, Department of Medicine, The Miriam Hospital and Rhode Island Hospital, Providence, Rhode Island, USA
| | - Zhijin J. Wu
- Department of Biostatistics, Brown University, Providence, Rhode Island, USA
| | - Michael C. Newstein
- Department of Medicine, Milford Regional Medical Center, and University of Massachusetts Medical School, Milford, Massachusetts, USA
| | - Mark S. Dooner
- Division of Hematology and Oncology, Department of Medicine, Rhode Island Hospital, and Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Jennifer Friedman
- Center for International Health Research, Rhode Island Hospital, Providence, Rhode Island, USA
- Department of Pediatrics, Rhode Island Hospital, and Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Michelle A. Lally
- Division of Infectious Diseases, Department of Medicine, The Miriam Hospital and Rhode Island Hospital, Providence, Rhode Island, USA
- Providence Veterans Affairs Medical Center, Providence, Rhode Island, USA
- Lifespan/Tufts/Brown Center for AIDS Research, Providence, Rhode Island, USA
| | - Bharat Ramratnam
- Laboratory of Retrovirology, Division of Infectious Diseases, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
- Division of Infectious Diseases, Department of Medicine, The Miriam Hospital and Rhode Island Hospital, Providence, Rhode Island, USA
- Lifespan/Tufts/Brown Center for AIDS Research, Providence, Rhode Island, USA
- COBRE Center for Cancer Research, Rhode Island Hospital, and Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
- Clinical Research Center of Lifespan, Providence, Rhode Island, USA
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26
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Druce M, Hulo C, Masson P, Sommer P, Xenarios I, Le Mercier P, De Oliveira T. Improving HIV proteome annotation: new features of BioAfrica HIV Proteomics Resource. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2016; 2016:baw045. [PMID: 27087306 PMCID: PMC4834208 DOI: 10.1093/database/baw045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 03/11/2016] [Indexed: 02/06/2023]
Abstract
The Human Immunodeficiency Virus (HIV) is one of the pathogens that cause the greatest global concern, with approximately 35 million people currently infected with HIV. Extensive HIV research has been performed, generating a large amount of HIV and host genomic data. However, no effective vaccine that protects the host from HIV infection is available and HIV is still spreading at an alarming rate, despite effective antiretroviral (ARV) treatment. In order to develop effective therapies, we need to expand our knowledge of the interaction between HIV and host proteins. In contrast to virus proteins, which often rapidly evolve drug resistance mutations, the host proteins are essentially invariant within all humans. Thus, if we can identify the host proteins needed for virus replication, such as those involved in transporting viral proteins to the cell surface, we have a chance of interrupting viral replication. There is no proteome resource that summarizes this interaction, making research on this subject a difficult enterprise. In order to fill this gap in knowledge, we curated a resource presents detailed annotation on the interaction between the HIV proteome and host proteins. Our resource was produced in collaboration with ViralZone and used manual curation techniques developed by UniProtKB/Swiss-Prot. Our new website also used previous annotations of the BioAfrica HIV-1 Proteome Resource, which has been accessed by approximately 10 000 unique users a year since its inception in 2005. The novel features include a dedicated new page for each HIV protein, a graphic display of its function and a section on its interaction with host proteins. Our new webpages also add information on the genomic location of each HIV protein and the position of ARV drug resistance mutations. Our improved BioAfrica HIV-1 Proteome Resource fills a gap in the current knowledge of biocuration. Database URL: http://www.bioafrica.net/proteomics/HIVproteome.html
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Affiliation(s)
- Megan Druce
- Africa Centre for Population Health, School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa Division of Genetics, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Chantal Hulo
- Swiss-Prot Group, SIB Swiss Institute of Bioinformatics, Geneva, Switzerland
| | - Patrick Masson
- Swiss-Prot Group, SIB Swiss Institute of Bioinformatics, Geneva, Switzerland
| | - Paula Sommer
- Division of Genetics, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Ioannis Xenarios
- Swiss-Prot Group, SIB Swiss Institute of Bioinformatics, Geneva, Switzerland
| | - Philippe Le Mercier
- Swiss-Prot Group, SIB Swiss Institute of Bioinformatics, Geneva, Switzerland
| | - Tulio De Oliveira
- Africa Centre for Population Health, School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
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27
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Bin Hamid F, Kim J, Shin CG. Cellular and viral determinants of retroviral nuclear entry. Can J Microbiol 2015; 62:1-15. [PMID: 26553381 DOI: 10.1139/cjm-2015-0350] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Retroviruses must integrate their cDNA into the host genome to generate proviruses. Viral DNA-protein complexes interact with cellular proteins and produce pre-integration complexes, which carry the viral genome and cross the nuclear pore channel to enter the nucleus and integrate viral DNA into host chromosomal DNA. If the reverse transcripts fail to integrate, linear or circular DNA species such as 1- and 2-long terminal repeats are generated. Such complexes encounter numerous cellular proteins in the cytoplasm, which restrict viral infection and protect the nucleus. To overcome host cell defenses, the pathogens have evolved several evasion strategies. Viral proteins often contain nuclear localization signals, allowing entry into the nucleus. Among more than 1000 proteins identified as required for HIV infection by RNA interference screening, karyopherins, cleavage and polyadenylation specific factor 6, and nucleoporins have been predominantly studied. This review discusses current opinions about the synergistic relationship between the viral and cellular factors involved in nuclear import, with focus on the unveiled mysteries of the host-pathogen interaction, and highlights novel approaches to pinpoint therapeutic targets.
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Affiliation(s)
- Faysal Bin Hamid
- Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea.,Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea
| | - Jinsun Kim
- Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea.,Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea
| | - Cha-Gyun Shin
- Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea.,Department of Systems Biotechnology, Chung-Ang University, Ansung 456-756, Republic of Korea
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28
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Ali MK, Kim J, Hamid FB, Shin CG. Knockdown of the host cellular protein transportin 3 attenuates prototype foamy virus infection. Biosci Biotechnol Biochem 2015; 79:943-51. [PMID: 25660973 DOI: 10.1080/09168451.2015.1008973] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Transportin 3 (TNPO3) is a member of the importin-ß superfamily proteins. Despite numerous studies, the exact molecular mechanism of TNPO3 in retroviral infection is still controversial. Here, we provide evidence for the role and mechanism of TNPO3 in the replication of prototype foamy virus (PFV). Our findings revealed that PFV infection was reduced 2-fold by knockdown (KD) of TNPO3. However, late stage of viral replication including transcription, translation, viral assembly, and release was not influenced. The differential cellular localization of PFV integrase (IN) in KD cells pinpointed a remarkable reduction of viral replication at the nuclear import step. We also found that TNPO3 interacted with PFV IN but not with Gag, suggesting that IN-TNPO3 interaction is important for nuclear import of PFV pre-integration complex. Our report enlightens the mechanism of PFV interaction with TNPO3 and support ongoing research on PFV as a promising safe vector for gene therapy.
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Affiliation(s)
- Md Khadem Ali
- a Department of Systems Biotechnology , Chung Ang University , Ansung , Republic of Korea
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29
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Comparison Between Several Integrase-defective Lentiviral Vectors Reveals Increased Integration of an HIV Vector Bearing a D167H Mutant. MOLECULAR THERAPY-NUCLEIC ACIDS 2014; 3:e213. [PMID: 25462529 PMCID: PMC4272407 DOI: 10.1038/mtna.2014.65] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 10/09/2014] [Indexed: 01/20/2023]
Abstract
HIV-1 derived vectors are among the most efficient for gene transduction in mammalian tissues. As the parent virus, they carry out vector genome insertion into the host cell chromatin. Consequently, their preferential integration in transcribed genes raises several conceptual and safety issues. To address part of these questions, HIV-derived vectors have been engineered to be nonintegrating. This was mainly achieved by mutating HIV-1 integrase at functional hotspots of the enzyme enabling the development of streamlined nuclear DNA circles functional for transgene expression. Few integrase mutant vectors have been successfully tested so far for gene transfer. They are cleared with time in mitotic cells, but stable within nondividing retina cells or neurons. Here, we compared six HIV vectors carrying different integrases, either wild type or with different mutations (D64V, D167H, Q168A, K186Q+Q214L+Q216L, and RRK262-264AAH) shown to modify integrase enzymatic activity, oligomerization, or interaction with key cellular cofactor of HIV DNA integration as LEDGF/p75 or TNPO3. We show that these mutations differently affect the transduction efficiency as well as rates and patterns of integration of HIV-derived vectors suggesting their different processing in the nucleus. Surprisingly and most interestingly, we report that an integrase carrying the D167H substitution improves vector transduction efficiency and integration in both HEK-293T and primary CD34+ cells.
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30
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Kottyan LC, Zoller EE, Bene J, Lu X, Kelly JA, Rupert AM, Lessard CJ, Vaughn SE, Marion M, Weirauch MT, Namjou B, Adler A, Rasmussen A, Glenn S, Montgomery CG, Hirschfield GM, Xie G, Coltescu C, Amos C, Li H, Ice JA, Nath SK, Mariette X, Bowman S, Rischmueller M, Lester S, Brun JG, Gøransson LG, Harboe E, Omdal R, Cunninghame-Graham DS, Vyse T, Miceli-Richard C, Brennan MT, Lessard JA, Wahren-Herlenius M, Kvarnström M, Illei GG, Witte T, Jonsson R, Eriksson P, Nordmark G, Ng WF, Anaya JM, Rhodus NL, Segal BM, Merrill JT, James JA, Guthridge JM, Scofield RH, Alarcon-Riquelme M, Bae SC, Boackle SA, Criswell LA, Gilkeson G, Kamen DL, Jacob CO, Kimberly R, Brown E, Edberg J, Alarcón GS, Reveille JD, Vilá LM, Petri M, Ramsey-Goldman R, Freedman BI, Niewold T, Stevens AM, Tsao BP, Ying J, Mayes MD, Gorlova OY, Wakeland W, Radstake T, Martin E, Martin J, Siminovitch K, Moser Sivils KL, Gaffney PM, Langefeld CD, Harley JB, Kaufman KM. The IRF5-TNPO3 association with systemic lupus erythematosus has two components that other autoimmune disorders variably share. Hum Mol Genet 2014; 24:582-96. [PMID: 25205108 DOI: 10.1093/hmg/ddu455] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Exploiting genotyping, DNA sequencing, imputation and trans-ancestral mapping, we used Bayesian and frequentist approaches to model the IRF5-TNPO3 locus association, now implicated in two immunotherapies and seven autoimmune diseases. Specifically, in systemic lupus erythematosus (SLE), we resolved separate associations in the IRF5 promoter (all ancestries) and with an extended European haplotype. We captured 3230 IRF5-TNPO3 high-quality, common variants across 5 ethnicities in 8395 SLE cases and 7367 controls. The genetic effect from the IRF5 promoter can be explained by any one of four variants in 5.7 kb (P-valuemeta = 6 × 10(-49); OR = 1.38-1.97). The second genetic effect spanned an 85.5-kb, 24-variant haplotype that included the genes IRF5 and TNPO3 (P-valuesEU = 10(-27)-10(-32), OR = 1.7-1.81). Many variants at the IRF5 locus with previously assigned biological function are not members of either final credible set of potential causal variants identified herein. In addition to the known biologically functional variants, we demonstrated that the risk allele of rs4728142, a variant in the promoter among the lowest frequentist probability and highest Bayesian posterior probability, was correlated with IRF5 expression and differentially binds the transcription factor ZBTB3. Our analytical strategy provides a novel framework for future studies aimed at dissecting etiological genetic effects. Finally, both SLE elements of the statistical model appear to operate in Sjögren's syndrome and systemic sclerosis whereas only the IRF5-TNPO3 gene-spanning haplotype is associated with primary biliary cirrhosis, demonstrating the nuance of similarity and difference in autoimmune disease risk mechanisms at IRF5-TNPO3.
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Affiliation(s)
- Leah C Kottyan
- Division of Rheumatology, Center for Autoimmune Genomics and Etiology and US Department of Veterans Affairs Medical Center, Cincinnati, OH, USA
| | - Erin E Zoller
- Division of Rheumatology, Center for Autoimmune Genomics and Etiology and
| | - Jessica Bene
- Division of Rheumatology, Center for Autoimmune Genomics and Etiology and
| | - Xiaoming Lu
- Division of Rheumatology, Center for Autoimmune Genomics and Etiology and
| | - Jennifer A Kelly
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Andrew M Rupert
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Christopher J Lessard
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA Department of Pathology and
| | - Samuel E Vaughn
- Division of Rheumatology, Center for Autoimmune Genomics and Etiology and
| | - Miranda Marion
- Department of Biostatistical Sciences and Center for Public Health Genomics and
| | - Matthew T Weirauch
- Division of Rheumatology, Center for Autoimmune Genomics and Etiology and US Department of Veterans Affairs Medical Center, Cincinnati, OH, USA Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Bahram Namjou
- Division of Rheumatology, Center for Autoimmune Genomics and Etiology and
| | - Adam Adler
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Astrid Rasmussen
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Stuart Glenn
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Courtney G Montgomery
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | | | - Gang Xie
- Mount Sinai Hospital Samuel Lunenfeld Research Institute, Toronto, ON, Canada
| | | | - Chris Amos
- Department of Community and Family Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - He Li
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA Department of Pathology and
| | - John A Ice
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Swapan K Nath
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Xavier Mariette
- Department of Rheumatology, Hôpitaux Universitaires Paris-Sud, INSERM U1012, Le Kremlin Bicêtre, France
| | - Simon Bowman
- Rheumatology Department, University Hospital Birmingham, Birmingham, UK
| | | | | | - Sue Lester
- The Queen Elizabeth Hospital, Adelaide, Australia The University of Adelaide, Adelaide, Australia
| | - Johan G Brun
- Institute of Internal Medicine, University of Bergen, Bergen, Norway Department of Rheumatology, Haukeland University Hospital, Bergen, Norway
| | - Lasse G Gøransson
- Clinical Immunology Unit, Department of Internal Medicine, Stavanger University Hospital, Stavanger, Norway
| | - Erna Harboe
- Clinical Immunology Unit, Department of Internal Medicine, Stavanger University Hospital, Stavanger, Norway
| | - Roald Omdal
- Clinical Immunology Unit, Department of Internal Medicine, Stavanger University Hospital, Stavanger, Norway
| | | | - Tim Vyse
- Department of Medical and Molecular Genetics, King's College London, London, UK
| | - Corinne Miceli-Richard
- Department of Rheumatology, Hôpitaux Universitaires Paris-Sud, INSERM U1012, Le Kremlin Bicêtre, France
| | - Michael T Brennan
- Department of Oral Medicine, Carolinas Medical Center, Charlotte, NC, USA
| | | | | | | | - Gabor G Illei
- National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, USA
| | | | - Roland Jonsson
- Department of Rheumatology, Haukeland University Hospital, Bergen, Norway Broegelmann Research Laboratory, The Gade Institute, University of Bergen, Bergen, Norway
| | - Per Eriksson
- Department of Rheumatology, Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | - Gunnel Nordmark
- Department of Medical Sciences, Rheumatology, Uppsala University, Uppsala, Sweden
| | - Wan-Fai Ng
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | | | - Juan-Manuel Anaya
- Center for Autoimmune Diseases Research (CREA), Universidad del Rosario, Bogotá, Colombia
| | - Nelson L Rhodus
- Department of Oral Surgery, University of Minnesota School of Dentistry, Minneapolis, MN, USA
| | - Barbara M Segal
- Division of Rheumatology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Joan T Merrill
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Judith A James
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Joel M Guthridge
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - R Hal Scofield
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA Division of Veterans Affairs Medical Center, Oklahoma City, OK, USA Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Marta Alarcon-Riquelme
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA de Genómica e Investigación Oncológica (GENYO), Pfizer-Universidad de Granada-Junta de Andalucia, Granada, Spain
| | - Sang-Cheol Bae
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, South Korea
| | - Susan A Boackle
- Division of Rheumatology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Lindsey A Criswell
- Division of Rheumatology, Rosalind Russell Medical Research Center for Arthritis, University of California San Francisco, San Francisco, CA, USA
| | - Gary Gilkeson
- Division of Rheumatology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Diane L Kamen
- Division of Rheumatology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Chaim O Jacob
- Divison of Gastrointestinal and Liver Diseases, Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Robert Kimberly
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Elizabeth Brown
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jeffrey Edberg
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Graciela S Alarcón
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - John D Reveille
- Division of Rheumatology and Clinical Immunogenetics, The Univeristy of Texas Health Science Center at Houston, Houston, TX, USA
| | - Luis M Vilá
- University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico, USA
| | - Michelle Petri
- Division of Rheumatology, Johns Hopkins, Baltimore, MD, USA
| | | | | | - Timothy Niewold
- Division of Rheumatology and Immunology, Mayo Clinic, Rochester, MN, USA
| | - Anne M Stevens
- University of Washington and Seattle Children's Hospital, Seattle, WA, USA
| | - Betty P Tsao
- David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Jun Ying
- MD Anderson Cancer Center, University of Texas, Houston, TX, USA
| | - Maureen D Mayes
- MD Anderson Cancer Center, University of Texas, Houston, TX, USA
| | - Olga Y Gorlova
- MD Anderson Cancer Center, University of Texas, Houston, TX, USA
| | - Ward Wakeland
- University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Timothy Radstake
- Department of Rheumatology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Ezequiel Martin
- Instituto de Parasitología y Biomedicina López Neyra Avda, Granada, Spain and
| | - Javier Martin
- Instituto de Parasitología y Biomedicina López Neyra Avda, Granada, Spain and
| | - Katherine Siminovitch
- Mount Sinai Hospital Samuel Lunenfeld Research Institute, Toronto, ON, Canada Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Kathy L Moser Sivils
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Patrick M Gaffney
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Carl D Langefeld
- Department of Biostatistical Sciences and Center for Public Health Genomics and
| | - John B Harley
- Division of Rheumatology, Center for Autoimmune Genomics and Etiology and US Department of Veterans Affairs Medical Center, Cincinnati, OH, USA
| | - Kenneth M Kaufman
- Division of Rheumatology, Center for Autoimmune Genomics and Etiology and US Department of Veterans Affairs Medical Center, Cincinnati, OH, USA
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Shkriabai N, Dharmarajan V, Slaughter A, Kessl JJ, Larue RC, Feng L, Fuchs JR, Griffin PR, Kvaratskhelia M. A critical role of the C-terminal segment for allosteric inhibitor-induced aberrant multimerization of HIV-1 integrase. J Biol Chem 2014; 289:26430-26440. [PMID: 25118283 DOI: 10.1074/jbc.m114.589572] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Allosteric HIV-1 integrase (IN) inhibitors (ALLINIs) are a promising class of antiretroviral agents for clinical development. Although ALLINIs promote aberrant IN multimerization and inhibit IN interaction with its cellular cofactor LEDGF/p75 with comparable potencies in vitro, their primary mechanism of action in infected cells is through inducing aberrant multimerization of IN. Crystal structures have shown that ALLINIs bind at the IN catalytic core domain dimer interface and bridge two interacting subunits. However, how these interactions promote higher-order protein multimerization is not clear. Here, we used mass spectrometry-based protein footprinting to monitor surface topology changes in full-length WT and the drug-resistant A128T mutant INs in the presence of ALLINI-2. These experiments have identified protein-protein interactions that extend beyond the direct inhibitor binding site and which lead to aberrant multimerization of WT but not A128T IN. Specifically, we demonstrate that C-terminal residues Lys-264 and Lys-266 play an important role in the inhibitor induced aberrant multimerization of the WT protein. Our findings provide structural clues for exploiting IN multimerization as a new, attractive therapeutic target and are expected to facilitate development of improved inhibitors.
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Affiliation(s)
- Nikoloz Shkriabai
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
| | | | - Alison Slaughter
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
| | - Jacques J Kessl
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
| | - Ross C Larue
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
| | - Lei Feng
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
| | - James R Fuchs
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
| | - Patrick R Griffin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida 33458, and
| | - Mamuka Kvaratskhelia
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, Ohio 43210,.
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De Houwer S, Demeulemeester J, Thys W, Rocha S, Dirix L, Gijsbers R, Christ F, Debyser Z. The HIV-1 integrase mutant R263A/K264A is 2-fold defective for TRN-SR2 binding and viral nuclear import. J Biol Chem 2014; 289:25351-61. [PMID: 25063804 DOI: 10.1074/jbc.m113.533281] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Transportin-SR2 (Tnpo3, TRN-SR2), a human karyopherin encoded by the TNPO3 gene, has been identified as a cellular cofactor of HIV-1 replication, specifically interacting with HIV-1 integrase (IN). Whether this interaction mediates the nuclear import of HIV remains controversial. We previously characterized the TRN-SR2 binding interface in IN and introduced mutations at these positions to corroborate the biological relevance of the interaction. The pleiotropic nature of IN mutations complicated the interpretation. Indeed, all previously tested IN interaction mutants also affected RT. Here we report on a virus with a pair of IN mutations, IN(R263A/K264A), that significantly reduce interaction with TRN-SR2. The virus retains wild-type reverse transcription activity but displays a block in nuclear import and integration, as measured by quantitative PCR. The defect in integration of this mutant resulted in a smaller increase in the number of two-long terminal repeat circles than for virus specifically blocked at integration by raltegravir or catalytic site mutations (IN(D64N/D116N/E152Q)). Finally, using an eGFP-IN-labeled HIV fluorescence-based import assay, the defect in nuclear import was corroborated. These data altogether underscore the importance of the HIV-IN TRN-SR2 protein-protein interaction for HIV nuclear import and validate the IN/TRN-SR2 interaction interface as a promising target for future antiviral therapy.
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Affiliation(s)
- Stéphanie De Houwer
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Jonas Demeulemeester
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Wannes Thys
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Susana Rocha
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Lieve Dirix
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Rik Gijsbers
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Frauke Christ
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
| | - Zeger Debyser
- From the Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, 3000, Leuven, Belgium
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33
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Tsirkone VG, Beutels KG, Demeulemeester J, Debyser Z, Christ F, Strelkov SV. Structure of transportin SR2, a karyopherin involved in human disease, in complex with Ran. Acta Crystallogr F Struct Biol Commun 2014; 70:723-9. [PMID: 24915079 PMCID: PMC4051523 DOI: 10.1107/s2053230x14009492] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 04/28/2014] [Indexed: 11/10/2022] Open
Abstract
Transportin SR2 (TRN-SR2) is a β-type karyopherin responsible for the nuclear import of specific cargoes, including serine/arginine-rich splicing factors. The protein has been implicated in a variety of human diseases, including HIV infection, primary biliary cirrhosis and limb-girdle muscular dystrophy 1F. Towards understanding its molecular mechanism, a 2.9 Å resolution crystal structure of human TRN-SR2 complexed with the small GTPase Ran has been determined. TRN-SR2 is composed of 20 α-helical HEAT repeats forming a solenoid-like fold. The first nine repeats form a `cradle' for the binding of RanGTP, revealing similarities but also differences with respect to the related importin 13 complex.
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Affiliation(s)
- Vicky G. Tsirkone
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Katrien G. Beutels
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Jonas Demeulemeester
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Zeger Debyser
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Frauke Christ
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - Sergei V. Strelkov
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
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Larue RC, Plumb MR, Crowe BL, Shkriabai N, Sharma A, DiFiore J, Malani N, Aiyer SS, Roth MJ, Bushman FD, Foster MP, Kvaratskhelia M. Bimodal high-affinity association of Brd4 with murine leukemia virus integrase and mononucleosomes. Nucleic Acids Res 2014; 42:4868-81. [PMID: 24520112 PMCID: PMC4005663 DOI: 10.1093/nar/gku135] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The importance of understanding the molecular mechanisms of murine leukemia virus (MLV) integration into host chromatin is highlighted by the development of MLV-based vectors for human gene-therapy. We have recently identified BET proteins (Brd2, 3 and 4) as the main cellular binding partners of MLV integrase (IN) and demonstrated their significance for effective MLV integration at transcription start sites. Here we show that recombinant Brd4, a representative of the three BET proteins, establishes complementary high-affinity interactions with MLV IN and mononucleosomes (MNs). Brd4(1–720) but not its N- or C-terminal fragments effectively stimulate MLV IN strand transfer activities in vitro. Mass spectrometry- and NMR-based approaches have enabled us to map key interacting interfaces between the C-terminal domain of BRD4 and the C-terminal tail of MLV IN. Additionally, the N-terminal fragment of Brd4 binds to both DNA and acetylated histone peptides, allowing it to bind tightly to MNs. Comparative analyses of the distributions of various histone marks along chromatin revealed significant positive correlations between H3- and H4-acetylated histones, BET protein-binding sites and MLV-integration sites. Our findings reveal a bimodal mechanism for BET protein-mediated MLV integration into select chromatin locations.
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Affiliation(s)
- Ross C Larue
- Center for Retrovirus Research and College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, USA, Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA and Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA
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Meehan AM, Saenz DT, Guevera R, Morrison JH, Peretz M, Fadel HJ, Hamada M, van Deursen J, Poeschla EM. A cyclophilin homology domain-independent role for Nup358 in HIV-1 infection. PLoS Pathog 2014; 10:e1003969. [PMID: 24586169 PMCID: PMC3930637 DOI: 10.1371/journal.ppat.1003969] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 01/15/2014] [Indexed: 12/05/2022] Open
Abstract
The large nucleoporin Nup358/RanBP2 forms eight filaments that project from the nuclear pore into the cytoplasm where they function as docking platforms for nucleocytoplasmic transport receptors. RNAi screens have implicated Nup358 in the HIV-1 life cycle. The 164 C-terminal amino acids of this 3,224 amino acid protein are a cyclophilin homology domain (Nup358Cyp), which has potential to bind the HIV-1 capsid and regulate viral progress to integration. Here we examined the virological role of Nup358 in conditional knockout mouse cells and in RNAi-depleted human CD4⁺ T cells. Cre-mediated gene knockout was toxic and diminished HIV-1 infectivity. However, cellular health and HIV-1 susceptibility were coordinately preserved if, prior to gene inactivation, a transposon was used to express all of Nup358 or only the N-terminal 1340 amino acids that contain three FG repeats and a Ran-binding domain. HIV-1, but not N74D capsid-mutant HIV-1, was markedly sensitive to TNPO3 depletion, but they infected 1-1340 segment-complemented Nup358 knockout cells equivalently. Human and mouse CypA both rescued HIV-1 in CypA gene⁻/⁻ Jurkat cells and TRIM-Nup358Cyp fusions derived from each species were equally antiviral; each also inhibited both WT and N74D virus. In the human CD4⁺T cell line SupT1, abrupt Nup358 depletion reduced viral replication but stable Nup358-depleted cells replicated HIV-1 normally. Thus, human CD4⁺ T cells can accommodate to loss of Nup358 and preserve HIV-1 susceptibility. Experiments with cylosporine, viruses with capsids that do not bind cyclophilins, and growth arrest did not uncover viral dependency on the C-terminal domains of Nup358. Our data reinforce the virological importance of TNPO3 and show that Nup358 supports nuclear transport functions important for cellular homeostasis and for HIV-1 nuclear import. However, the results do not suggest direct roles for the Nup358 cyclophilin or SUMO E3 ligase domains in engaging the HIV-1 capsid prior to nuclear translocation.
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Affiliation(s)
- Anne M. Meehan
- Department of Molecular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Dyana T. Saenz
- Department of Molecular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Rebekah Guevera
- Department of Molecular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - James H. Morrison
- Department of Molecular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Mary Peretz
- Department of Molecular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Hind J. Fadel
- Department of Molecular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Masakazu Hamada
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Jan van Deursen
- Department of Biochemistry & Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Eric M. Poeschla
- Department of Molecular Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
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36
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Structural basis for nuclear import of splicing factors by human Transportin 3. Proc Natl Acad Sci U S A 2014; 111:2728-33. [PMID: 24449914 DOI: 10.1073/pnas.1320755111] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Transportin 3 (Tnpo3, Transportin-SR2) is implicated in nuclear import of splicing factors and HIV-1 replication. Herein, we show that the majority of cellular Tnpo3 binding partners contain arginine-serine (RS) repeat domains and present crystal structures of human Tnpo3 in its free as well as GTPase Ran- and alternative splicing factor/splicing factor 2 (ASF/SF2)-bound forms. The flexible β-karyopherin fold of Tnpo3 embraces the RNA recognition motif and RS domains of the cargo. A constellation of charged residues on and around the arginine-rich helix of Tnpo3 HEAT repeat 15 engage the phosphorylated RS domain and are critical for the recognition and nuclear import of ASF/SF2. Mutations in the same region of Tnpo3 impair its interaction with the cleavage and polyadenylation specificity factor 6 (CPSF6) and its ability to support HIV-1 replication. Steric incompatibility of the RS domain and RanGTP engagement by Tnpo3 provides the mechanism for cargo release in the nucleus. Our results elucidate the structural bases for nuclear import of splicing factors and the Tnpo3-CPSF6 nexus in HIV-1 biology.
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37
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Viral and cellular requirements for the nuclear entry of retroviral preintegration nucleoprotein complexes. Viruses 2013; 5:2483-511. [PMID: 24103892 PMCID: PMC3814599 DOI: 10.3390/v5102483] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/26/2013] [Accepted: 10/03/2013] [Indexed: 02/07/2023] Open
Abstract
Retroviruses integrate their reverse transcribed genomes into host cell chromosomes as an obligate step in virus replication. The nuclear envelope separates the chromosomes from the cell cytoplasm during interphase, and different retroviral groups deal with this physical barrier in different ways. Gammaretroviruses are dependent on the passage of target cells through mitosis, where they are believed to access chromosomes when the nuclear envelope dissolves for cell division. Contrastingly, lentiviruses such as HIV-1 infect non-dividing cells, and are believed to enter the nucleus by passing through the nuclear pore complex. While numerous virally encoded elements have been proposed to be involved in HIV-1 nuclear import, recent evidence has highlighted the importance of HIV-1 capsid. Furthermore, capsid was found to be responsible for the viral requirement of various nuclear transport proteins, including transportin 3 and nucleoporins NUP153 and NUP358, during infection. In this review, we describe our current understanding of retroviral nuclear import, with emphasis on recent developments on the role of the HIV-1 capsid protein.
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New insights in the role of nucleoporins: a bridge leading to concerted steps from HIV-1 nuclear entry until integration. Virus Res 2013; 178:187-96. [PMID: 24051001 DOI: 10.1016/j.virusres.2013.09.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/01/2013] [Accepted: 09/02/2013] [Indexed: 11/22/2022]
Abstract
Human Immunodeficiency virus type 1 (HIV-1), as well as many other viruses that depend on nuclear entry for replication, has developed an evolutionary strategy to dock and translocate through the nuclear pore complex (NPC). In particular, the nuclear pore is not a static window but it is a dynamic structure involved in many vital cellular functions, as nuclear import/export, gene regulation, chromatin organization and genome stability. This review aims to shed light on viral mechanisms developed by HIV-1 to usurp cellular machinery to favor viral gene expression and their replication. In particular, it will be reviewed both what is known and what is speculated about the link between HIV translocation through the nuclear pore and the proviral integration in the host chromatin.
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Taltynov O, Demeulemeester J, Christ F, De Houwer S, Tsirkone VG, Gerard M, Weeks SD, Strelkov SV, Debyser Z. Interaction of transportin-SR2 with Ras-related nuclear protein (Ran) GTPase. J Biol Chem 2013; 288:25603-25613. [PMID: 23878195 DOI: 10.1074/jbc.m113.484345] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) and other lentiviruses are capable of infecting non-dividing cells and, therefore, need to be imported into the nucleus before integration into the host cell chromatin. Transportin-SR2 (TRN-SR2, Transportin-3, TNPO3) is a cellular karyopherin implicated in nuclear import of HIV-1. A model in which TRN-SR2 imports the viral preintegration complex into the nucleus is supported by direct interaction between TRN-SR2 and HIV-1 integrase (IN). Residues in the C-terminal domain of HIV-1 IN that mediate binding to TRN-SR2 were recently delineated. As for most nuclear import cargoes, the driving force behind HIV-1 preintegration complex import is likely a gradient of the GDP- and GTP-bound forms of Ran, a small GTPase. In this study we offer biochemical and structural characterization of the interaction between TRN-SR2 and Ran. By size exclusion chromatography we demonstrate stable complex formation of TRN-SR2 and RanGTP in solution. Consistent with the behavior of normal nuclear import cargoes, HIV-1 IN is released from the complex with TRN-SR2 by RanGTP. Although in concentrated solutions TRN-SR2 by itself was predominantly present as a dimer, the TRN-SR2-RanGTP complex was significantly more compact. Further analysis supported a model wherein one monomer of TRN-SR2 is bound to one monomer of RanGTP. Finally, we present a homology model of the TRN-SR2-RanGTP complex that is in excellent agreement with the experimental small angle x-ray scattering data.
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Affiliation(s)
- Oliver Taltynov
- From the Laboratory for Molecular Virology and Gene Therapy and
| | | | - Frauke Christ
- From the Laboratory for Molecular Virology and Gene Therapy and
| | | | - Vicky G Tsirkone
- Laboratory for Biocrystallography, KU Leuven, B-3000 Leuven, Belgium
| | - Melanie Gerard
- From the Laboratory for Molecular Virology and Gene Therapy and
| | - Stephen D Weeks
- Laboratory for Biocrystallography, KU Leuven, B-3000 Leuven, Belgium
| | - Sergei V Strelkov
- Laboratory for Biocrystallography, KU Leuven, B-3000 Leuven, Belgium
| | - Zeger Debyser
- From the Laboratory for Molecular Virology and Gene Therapy and.
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Melià MJ, Kubota A, Ortolano S, Vílchez JJ, Gámez J, Tanji K, Bonilla E, Palenzuela L, Fernández-Cadenas I, Pristoupilová A, García-Arumí E, Andreu AL, Navarro C, Hirano M, Martí R. Limb-girdle muscular dystrophy 1F is caused by a microdeletion in the transportin 3 gene. ACTA ACUST UNITED AC 2013; 136:1508-17. [PMID: 23543484 PMCID: PMC3634201 DOI: 10.1093/brain/awt074] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In 2001, we reported linkage of an autosomal dominant form of limb-girdle muscular dystrophy, limb-girdle muscular dystrophy 1F, to chromosome 7q32.1-32.2, but the identity of the mutant gene was elusive. Here, using a whole genome sequencing strategy, we identified the causative mutation of limb-girdle muscular dystrophy 1F, a heterozygous single nucleotide deletion (c.2771del) in the termination codon of transportin 3 (TNPO3). This gene is situated within the chromosomal region linked to the disease and encodes a nuclear membrane protein belonging to the importin beta family. TNPO3 transports serine/arginine-rich proteins into the nucleus, and has been identified as a key factor in the HIV-import process into the nucleus. The mutation is predicted to generate a 15-amino acid extension of the C-terminus of the protein, segregates with the clinical phenotype, and is absent in genomic sequence databases and a set of >200 control alleles. In skeletal muscle of affected individuals, expression of the mutant messenger RNA and histological abnormalities of nuclei and TNPO3 indicate altered TNPO3 function. Our results demonstrate that the TNPO3 mutation is the cause of limb-girdle muscular dystrophy 1F, expand our knowledge of the molecular basis of muscular dystrophies and bolster the importance of defects of nuclear envelope proteins as causes of inherited myopathies.
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Affiliation(s)
- Maria J Melià
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, VHIR, Universitat Autònoma de Barcelona, Passeig Vall d'Hebron, 119-129 08035 Barcelona, Spain
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Khadem Ali M, Alamgir Hossain M, Shin CG. Comparative sequence and expression analyses of African green monkey (Cercopithecus aethiops) TNPO3 from CV-1 cells. Genes Genomics 2013. [DOI: 10.1007/s13258-013-0102-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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42
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De Iaco A, Santoni F, Vannier A, Guipponi M, Antonarakis S, Luban J. TNPO3 protects HIV-1 replication from CPSF6-mediated capsid stabilization in the host cell cytoplasm. Retrovirology 2013; 10:20. [PMID: 23414560 PMCID: PMC3599327 DOI: 10.1186/1742-4690-10-20] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 02/11/2013] [Indexed: 11/30/2022] Open
Abstract
Background Despite intensive investigation the mechanism by which HIV-1 reaches the host cell nucleus is unknown. TNPO3, a karyopherin mediating nuclear entry of SR-proteins, was shown to be required for HIV-1 infectivity. Some investigators have reported that TNPO3 promotes HIV-1 nuclear import, as would be expected for a karyopherin. Yet, an equal number of investigators have failed to obtain evidence that supports this model. Here, a series of experiments were performed to better elucidate the mechanism by which TNPO3 promotes HIV-1 infectivity. Results To examine the role of TNPO3 in HIV-1 replication, the 2-LTR circles that are commonly used as a marker for HIV-1 nuclear entry were cloned after infection of TNPO3 knockdown cells. Potential explanation for the discrepancy in the literature concerning the effect of TNPO3 was provided by sequencing hundreds of these clones: a significant fraction resulted from autointegration into sites near the LTRs and therefore were not bona fide 2-LTR circles. In response to this finding, new techniques were developed to monitor HIV-1 cDNA, including qPCR reactions that distinguish 2-LTR circles from autointegrants, as well as massive parallel sequencing of HIV-1 cDNA. With these assays, TNPO3 knockdown was found to reduce the levels of 2-LTR circles. This finding was puzzling, though, since previous work has shown that the HIV-1 determinant for TNPO3-dependence is capsid (CA), an HIV-1 protein that forms a mega-dalton protein lattice in the cytoplasm. TNPO3 imports cellular splicing factors via their SR-domain. Attention was therefore directed towards CPSF6, an SR-protein that binds HIV-1 CA and inhibits HIV-1 nuclear import when the C-terminal SR-domain is deleted. The effect of 27 HIV-1 capsid mutants on sensitivity to TNPO3 knockdown was then found to correlate strongly with sensitivity to inhibition by a C-terminal deletion mutant of CPSF6 (R2 = 0.883, p < 0.0001). TNPO3 knockdown was then shown to cause CPSF6 to accumulate in the cytoplasm. Mislocalization of CPSF6 to the cytoplasm, whether by TNPO3 knockdown, deletion of the CPSF6 nuclear localization signal, or by fusion of CPSF6 to a nuclear export signal, resulted in inhibition of HIV-1 replication. Additionally, targeting CPSF6 to the nucleus by fusion to a heterologous nuclear localization signal rescued HIV-1 from the inhibitory effects of TNPO3 knockdown. Finally, mislocalization of CPSF6 to the cytoplasm was associated with abnormal stabilization of the HIV-1 CA core. Conclusion TNPO3 promotes HIV-1 infectivity indirectly, by shifting the CA-binding protein CPSF6 to the nucleus, thus preventing the excessive HIV-1 CA stability that would otherwise result from cytoplasmic accumulation of CPSF6.
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Affiliation(s)
- Alberto De Iaco
- Department of Microbiology and Molecular Medicine, University of Geneva, 1205, Geneva, Switzerland
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43
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De Houwer S, Demeulemeester J, Thys W, Taltynov O, Zmajkovicova K, Christ F, Debyser Z. Identification of residues in the C-terminal domain of HIV-1 integrase that mediate binding to the transportin-SR2 protein. J Biol Chem 2012; 287:34059-68. [PMID: 22872638 DOI: 10.1074/jbc.m112.387944] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Transportin-SR2 (TRN-SR2 and TNPO3) is a cellular cofactor of HIV replication that has been implicated in the nuclear import of HIV. TRN-SR2 was originally identified in a yeast two-hybrid screen as an interaction partner of HIV integrase (IN) and in two independent siRNA screens as a cofactor of viral replication. We have now studied the interaction of TRN-SR2 and HIV IN in molecular detail and identified the TRN-SR2 interacting regions of IN. A weak interaction with the catalytic core domain (CCD) and a strong interaction with the C-terminal domain (CTD) of IN were detected. By dissecting the catalytic core domain (CCD) of IN into short structural fragments, we identified a peptide (INIP(1), amino acids (170)EHLKTAVQMAVFIHNFKRKGGI(191)) retaining the ability to interact with TRN-SR2. By dissecting the C-terminal domain (CTD) of IN, we could identify two interacting peptides (amino acids (214)QKQITKIQNFRVYYR(228) and (262)RRKVKIIRDYGK(273)) that come together in the CTD tertiary structure to form an exposed antiparallel β-sheet. Through site-specific mutagenesis, we defined the following sets of amino acids in IN as important for the interaction with TRN-SR2: Phe-185/Lys-186/Arg-187/Lys-188 in the CCD and Arg-262/Arg-263/Lys-264 and Lys-266/Arg-269 in the CTD. An HIV-1 strain carrying K266A/R269A in IN was replication-defective due to a block in reverse transcription, confounding the study of nuclear import. Insight into the IN/TRN-SR2 interaction interface is necessary to guide drug discovery efforts targeting the nuclear entry step of replication.
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Affiliation(s)
- Stephanie De Houwer
- Laboratory for Molecular Virology and Gene Therapy, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
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