scholarly journals Oligomerization Requirements for MX2-Mediated Suppression of HIV-1 Infection

2015 ◽  
Vol 90 (1) ◽  
pp. 22-32 ◽  
Author(s):  
Matthew D. J. Dicks ◽  
Caroline Goujon ◽  
Darja Pollpeter ◽  
Gilberto Betancor ◽  
Luis Apolonia ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Structure Function ◽  
Influenza A ◽  
Acute Infection ◽  
Higher Order ◽  
Nuclear Accumulation ◽  
Antiviral Function ◽  
Ring Structures ◽  
Hiv 1

ABSTRACTHuman myxovirus resistance 2 (MX2/MXB) is an interferon-stimulated gene (ISG) and was recently identified as a late postentry suppressor of human immunodeficiency virus type 1 (HIV-1) infection, inhibiting the nuclear accumulation of viral cDNAs. Although the HIV-1 capsid (CA) protein is believed to be the viral determinant of MX2-mediated inhibition, the precise mechanism of antiviral action remains unclear. The MX family of dynamin-like GTPases also includes MX1/MXA, a well-studied inhibitor of a range of RNA and DNA viruses, including influenza A virus (FLUAV) and hepatitis B virus but not retroviruses. MX1 and MX2 are closely related and share similar domain architectures and structures. However, MX2 possesses an extended N terminus that is essential for antiviral function and confers anti-HIV-1 activity on MX1 [MX1(NMX2)]. Higher-order oligomerization is required for the antiviral activity of MX1 against FLUAV, with current models proposing that MX1 forms ring structures that constrict around viral nucleoprotein complexes. Here, we performed structure-function studies to investigate the requirements for oligomerization of both MX2 and chimeric MX1(NMX2) for the inhibition of HIV-1 infection. The oligomerization state of mutated proteins with amino acid substitutions at multiple putative oligomerization interfaces was assessed using a combination of covalent cross-linking and coimmunoprecipitation. We show that while monomeric MX2 and MX1(NMX2) mutants are not antiviral, higher-order oligomerization does not appear to be required for full antiviral activity of either protein. We propose that lower-order oligomerization of MX2 is sufficient for the effective inhibition of HIV-1.IMPORTANCEInterferon plays an important role in the control of virus replication during acute infectionin vivo. Recently, cultured cell experiments identified human MX2 as a key effector in the interferon-mediated postentry block to HIV-1 infection. MX2 is a member of a family of large dynamin-like GTPases that includes MX1/MXA, a closely related interferon-inducible inhibitor of several viruses, including FLUAV, but not HIV-1. MX GTPases form higher-order oligomeric structures, and the oligomerization of MX1 is required for inhibitory activity against many of its viral targets. Through structure-function studies, we report that monomeric mutants of MX2 do not inhibit HIV-1. However, in contrast to MX1, oligomerization beyond dimer assembly does not seem to be required for the antiviral activity of MX2, implying that fundamental differences exist between the antiviral mechanisms employed by these closely related proteins.

scholarly journals SUMOylation of SAMHD1 at Lysine 595 is required for HIV-1 restriction in non-cycling cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Charlotte Martinat ◽  
Arthur Cormier ◽  
Joëlle Tobaly-Tapiero ◽  
Noé Palmic ◽  
Nicoletta Casartelli ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Reverse Transcription ◽  
Immune Cells ◽  
Viral Restriction ◽  
Antiviral Function ◽  
Hiv 1 ◽  
Constitutively Active

AbstractSAMHD1 is a cellular triphosphohydrolase (dNTPase) proposed to inhibit HIV-1 reverse transcription in non-cycling immune cells by limiting the supply of the dNTP substrates. Yet, phosphorylation of T592 downregulates SAMHD1 antiviral activity, but not its dNTPase function, implying that additional mechanisms contribute to viral restriction. Here, we show that SAMHD1 is SUMOylated on residue K595, a modification that relies on the presence of a proximal SUMO-interacting motif (SIM). Loss of K595 SUMOylation suppresses the restriction activity of SAMHD1, even in the context of the constitutively active phospho-ablative T592A mutant but has no impact on dNTP depletion. Conversely, the artificial fusion of SUMO2 to a non-SUMOylatable inactive SAMHD1 variant restores its antiviral function, a phenotype that is reversed by the phosphomimetic T592E mutation. Collectively, our observations clearly establish that lack of T592 phosphorylation cannot fully account for the restriction activity of SAMHD1. We find that SUMOylation of K595 is required to stimulate a dNTPase-independent antiviral activity in non-cycling immune cells, an effect that is antagonized by cyclin/CDK-dependent phosphorylation of T592 in cycling cells.

scholarly journals Antiviral activity of Ladania067, an extract from wild black currant leaves against influenza A virus in vitro and in vivo

2014 ◽  
Vol 5 ◽  
Author(s):  
Emanuel Haasbach ◽  
Carmen Hartmayer ◽  
Alice Hettler ◽  
Alicja Sarnecka ◽  
Ulrich Wulle ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Influenza A Virus ◽  
Influenza A ◽  
Black Currant

scholarly journals Novel Antiviral Activities of Obatoclax, Emetine, Niclosamide, Brequinar, and Homoharringtonine

2019 ◽  
Author(s):  
Petter I. Andersen ◽  
Klara Krpina ◽  
Aleksandr Ianevski ◽  
Nastassia Shtaida ◽  
Eunji Jo ◽  
...  
Keyword(s):  
Influenza A ◽  
Rift Valley Fever Virus ◽  
Antiviral Agents ◽  
Viral Disease ◽  
World Health ◽  
Valley Fever ◽  
The World ◽  
Health Organization ◽  
Hiv 1

Viruses are the major causes of acute and chronic infectious diseases in the world. According to the World Health Organization, there is an urgent need for better control of viral diseases. Re-purposing existing antiviral agents from one viral disease to another could play a pivotal role in this process. Here we identified novel activities of obatoclax and emetine against herpes simplex virus type 2 (HSV-2), human immunodeficiency virus 1 (HIV-1), echovirus 1 (EV1), human metapneumovirus (HMPV) and Rift Valley fever virus (RVFV) in cell cultures. Moreover, we demonstrated novel activities of emetine against influenza A virus (FluAV), niclosamide against HSV-2, brequinar against HIV-1, and homoharringtonine against EV1. Our findings may expand the spectrum of indications of these safe-in-man agents and reinforce the arsenal of available antiviral therapeutics pending the results of further in vivo tests.

scholarly journals In vitro and in vivo mechanism of immunomodulatory and antiviral activity of Edible Bird's Nest (EBN) against influenza A virus (IAV) infection

2016 ◽  
Vol 185 ◽  
pp. 327-340 ◽  
Author(s):  
Amin Haghani ◽  
Parvaneh Mehrbod ◽  
Nikoo Safi ◽  
Nur Ain Aminuddin ◽  
Azadeh Bahadoran ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Influenza A Virus ◽  
Influenza A ◽  
Edible Bird’S Nest

scholarly journals HIV-1 Vpr Accelerates Viral Replication during Acute Infection by Exploitation of Proliferating CD4+ T Cells In Vivo

2013 ◽  
Vol 9 (12) ◽  
pp. e1003812 ◽  
Author(s):  
Kei Sato ◽  
Naoko Misawa ◽  
Shingo Iwami ◽  
Yorifumi Satou ◽  
Masao Matsuoka ◽  
...  
Keyword(s):  
T Cells ◽  
Viral Replication ◽  
Cd4 T Cells ◽  
Acute Infection ◽  
Hiv 1

scholarly journals 7SL RNA Mediates Virion Packaging of the Antiviral Cytidine Deaminase APOBEC3G

2007 ◽  
Vol 81 (23) ◽  
pp. 13112-13124 ◽  
Author(s):  
Tao Wang ◽  
Chunjuan Tian ◽  
Wenyan Zhang ◽  
Kun Luo ◽  
Phuong Thi Nguyen Sarkis ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Rna Binding ◽  
Cytidine Deaminase ◽  
Rna Packaging ◽  
Cellular Functions ◽  
7Sl Rna ◽  
Immunodeficiency Virus ◽  
Antiviral Function ◽  
Pol Iii ◽  
Hiv 1

ABSTRACT Cytidine deaminase APOBEC3G (A3G) has broad antiviral activity against diverse retroviruses and/or retrotransposons, and its antiviral functions are believed to rely on its encapsidation into virions in an RNA-dependent fashion. However, the cofactors of A3G virion packaging have not yet been identified. We demonstrate here that A3G selectively interacts with certain polymerase III (Pol III)-derived RNAs, including Y3 and 7SL RNAs. Among A3G-binding Pol III-derived RNAs, 7SL RNA was preferentially packaged into human immunodeficiency virus type 1 (HIV-1) particles. Efficient packaging of 7SL RNA, as well as A3G, was mediated by the RNA-binding nucleocapsid domain of HIV-1 Gag. A3G mutants that had reduced 7SL RNA binding but maintained wild-type levels of mRNA and tRNA binding were packaged poorly and had impaired antiviral activity. Reducing 7SL RNA packaging by overexpression of SRP19 proteins inhibited 7SL RNA and A3G virion packaging and impaired its antiviral function. Thus, 7SL RNA that is encapsidated into diverse retroviruses is a key cofactor of the antiviral A3G. This selective interaction of A3G with certain Pol III-derived RNAs raises the question of whether A3G and its cofactors may have as-yet-unidentified cellular functions.

scholarly journals Antiviral activity of Chongkukjang extracts against influenza A virus in vitro and in vivo

2015 ◽  
Vol 2 (2) ◽  
pp. 47-51 ◽  
Author(s):  
Bai Wei ◽  
Se-Yeoun Cha ◽  
Min Kang ◽  
Young Jin Kim ◽  
Chang-Won Cho ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Influenza A Virus ◽  
Influenza A

scholarly journals NICTABA and UDA, two GlcNAc-binding lectins with unique antiviral activity profiles

2015 ◽  
Vol 70 (6) ◽  
pp. 1674-1685 ◽  
Author(s):  
Stephanie C. Gordts ◽  
Marleen Renders ◽  
Geoffrey Férir ◽  
Dana Huskens ◽  
Els J. M. Van Damme ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
Antiviral Activity ◽  
Influenza A ◽  
Specific Binding ◽  
Tobacco Plant ◽  
Human Monoclonal Antibody ◽  
Envelope Glycoproteins ◽  
Carbohydrate Binding ◽  
Enveloped Viruses ◽  
Hiv 1

Abstract Objectives This study aimed to assess the antiviral properties of a unique lectin (NICTABA) produced by the tobacco plant, Nicotiana tabacum. Methods Cellular assays were used to investigate the antiviral activity of NICTABA and Urtica dioica agglutinin (UDA). Surface plasmon resonance (SPR) studies were performed to study the sugar specificity and the interactions of both lectins with the envelope glycoproteins of HIV-1. Results The N-acetyl-d-glucosamine (GlcNAc)-binding lectins exhibited broad-spectrum activity against several families of enveloped viruses including influenza A/B, Dengue virus type 2, herpes simplex virus types 1 and 2 and HIV-1/2. The IC50 of NICTABA for various HIV-1 strains, clinical isolates and HIV-2 assessed in PBMCs ranged from 5 to 30 nM. Furthermore, NICTABA inhibited syncytium formation between persistently HIV-1-infected T cells and uninfected CD4+ T lymphocytes and prevented DC-SIGN-mediated HIV-1 transmission to CD4+ target T lymphocytes. However, unlike many other antiviral carbohydrate-binding agents (CBAs) described so far, NICTABA did not block HIV-1 capture to DC-SIGN+ cells and it did not interfere with the binding of the human monoclonal antibody 2G12 to gp120. SPR studies with HIV-1 envelope glycoproteins showed that the affinity of NICTABA for gp120 and gp41 was in the low nanomolar range. The specific binding of NICTABA to gp120 could be prevented in the presence of a GlcNAc trimer, but not in the presence of mannose trimers. NICTABA displayed no antiviral activity against non-enveloped viruses. Conclusions Since CBAs possess a high genetic barrier for the development of viral resistance and NICTABA shows a broad antiviral activity profile, this CBA may qualify as a potential antiviral candidate with a pleiotropic mode of action aimed at targeting the entry of enveloped viruses.

scholarly journals Therapeutic Activity of an Anti-Idiotypic Antibody-Derived Killer Peptide against Influenza A Virus Experimental Infection

2008 ◽  
Vol 52 (12) ◽  
pp. 4331-4337 ◽  
Author(s):  
Giorgio Conti ◽  
Walter Magliani ◽  
Stefania Conti ◽  
Lucia Nencioni ◽  
Rossella Sgarbanti ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Inhibitory Activity ◽  
Influenza A ◽  
Particle Production ◽  
Killer Toxin ◽  
Mechanisms Of Action ◽  
Idiotypic Antibody ◽  
Hiv 1

ABSTRACT The in vitro and in vivo activities of a killer decapeptide (KP) against influenza A virus is described, and the mechanisms of action are suggested. KP represents the functional internal image of a yeast killer toxin that proved to exert antimicrobial and anti-human immunodeficiency virus type 1 (HIV-1) activities. Treatment with KP demonstrated a significant inhibitory activity on the replication of two strains of influenza A virus in different cell lines, as evaluated by hemagglutination, hemadsorption, and plaque assays. The complete inhibition of virus particle production and a marked reduction of the synthesis of viral proteins (membrane protein and hemagglutinin, in particular) were observed at a KP concentration of 4 μg/ml. Moreover, KP administered intraperitoneally at a dose of 100 μg/mice once a day for 10 days to influenza A/NWS/33 (H1N1) virus-infected mice improved the survival of the animals by 40% and significantly decreased the viral titers in their lungs. Overall, KP appears to be the first anti-idiotypic antibody-derived peptide that displays inhibitory activity and that has a potential therapeutic effect against pathogenic microorganisms, HIV-1, and influenza A virus by different mechanisms of action.

scholarly journals Effect of HIV-1 Env on SERINC5 Antagonism

2016 ◽  
Vol 91 (4) ◽  
Author(s):  
Saina Beitari ◽  
Shilei Ding ◽  
Qinghua Pan ◽  
Andrés Finzi ◽  
Chen Liang
Keyword(s):  
Antiviral Activity ◽  
High Frequency ◽  
Neutralizing Antibodies ◽  
Broadly Neutralizing Antibodies ◽  
Viral Loads ◽  
Virion Incorporation ◽  
Viral Particles ◽  
Ccr5 Inhibitor ◽  
Hiv 1

ABSTRACT SERINC5 is able to restrict HIV-1 infection by drastically impairing the infectivity of viral particles. Studies have shown that the HIV-1 Nef protein counters SERINC5 through downregulating SERINC5 from the cell surface and preventing the virion incorporation of SERINC5. In addition, the Env proteins of some HIV-1 strains can also overcome SERINC5 inhibition. However, it is unclear how HIV-1 Env does so and why HIV-1 has two mechanisms to resist SERINC5 inhibition. The results of this study show that neither Env nor Nef prevents high levels of ectopic SERINC5 from being incorporated into HIV-1 particles, except that Env, but not Nef, is able to resist inhibition by virion-associated SERINC5. Testing of a panel of HIV-1 Env proteins from different subtypes revealed a high frequency of SERINC5-resistant Envs. Interestingly, although the SERINC5-bearing viruses were not inhibited by SERINC5 itself, they became more sensitive to the CCR5 inhibitor maraviroc and some neutralizing antibodies than the SERINC5-free viruses, which suggests a possible influence of SERINC5 on Env function. We conclude that HIV-1 Env is able to overcome SERINC5 without preventing SERINC5 virion incorporation. IMPORTANCE HIV-1 Nef is known to enhance the infectivity of HIV-1 particles and to contribute to the maintenance of high viral loads in patients. However, the underlying molecular mechanism remained elusive until the recent discovery of the antiviral activity of SERINC5. SERINC5 profoundly inhibits HIV-1 but is antagonized by Nef, which prevents the incorporation of SERINC5 into viral particles. Here, we show that HIV-1 Env, but not Nef, is able to resist high levels of SERINC5 without excluding SERINC5 from incorporation into viral particles. However, the virion-associated SERINC5 renders HIV-1 more sensitive to some broadly neutralizing antibodies. It is possible that, under the pressure of some neutralizing antibodies in vivo, HIV-1 needs Nef to remove SERINC5 from viral particles, even though viral Env is able to resist virion-associated SERINC5.

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