HIV-1 and Ebola virus encode small peptide motifs that recruit Tsg101 to sites of particle assembly to facilitate egress

2001 ◽  
Vol 7 (12) ◽  
pp. 1313-1319 ◽  
Author(s):  
Juan Martin-Serrano ◽  
Trinity Zang ◽  
Paul D. Bieniasz
Keyword(s):  
Ebola Virus ◽  
Small Peptide ◽  
Particle Assembly ◽  
Peptide Motifs ◽  
Hiv 1

scholarly journals Broad-Spectrum Inhibition of Retroviral and Filoviral Particle Release by Tetherin

2008 ◽  
Vol 83 (4) ◽  
pp. 1837-1844 ◽  
Author(s):  
Nolwenn Jouvenet ◽  
Stuart J. D. Neil ◽  
Maria Zhadina ◽  
Trinity Zang ◽  
Zerina Kratovac ◽  
...  
Keyword(s):  
Ebola Virus ◽  
Specific Inhibitor ◽  
Marburg Virus ◽  
Immune Defense ◽  
Structural Proteins ◽  
Type I ◽  
Particle Assembly ◽  
Particle Release ◽  
Antiviral Genes ◽  
Hiv 1

ABSTRACT The expression of many putative antiviral genes is upregulated when cells encounter type I interferon (IFN), but the actual mechanisms by which many IFN-induced gene products inhibit virus replication are poorly understood. A recently identified IFN-induced antiretroviral protein, termed tetherin (previously known as BST-2 or CD317), blocks the release of nascent human immunodeficiency virus type 1 (HIV-1) particles from infected cells, and an HIV-1 accessory protein, Vpu, acts as a viral antagonist of tetherin. Here, we show that tetherin is capable of blocking not only the release of HIV-1 particles but also the release of particles assembled using the major structural proteins of a variety of prototype retroviruses, including members of the alpharetrovirus, betaretrovirus, deltaretrovirus, lentivirus, and spumaretrovirus families. Moreover, we show that the release of particles assembled using filovirus matrix proteins from Marburg virus and Ebola virus is also sensitive to inhibition by tetherin. These findings indicate that tetherin is a broadly specific inhibitor of enveloped particle release, and therefore, inhibition is unlikely to require specific interactions with viral proteins. Nonetheless, tetherin colocalized with nascent virus-like particles generated by several retroviral and filoviral structural proteins, indicating that it is present at, or recruited to, sites of particle assembly. Overall, tetherin is potentially active against many enveloped viruses and likely to be an important component of the antiviral innate immune defense.

scholarly journals Analysis of Human Immunodeficiency Virus Type 1 Gag Dimerization-Induced Assembly

2005 ◽  
Vol 79 (23) ◽  
pp. 14498-14506 ◽  
Author(s):  
Ayna Alfadhli ◽  
Tenzin Choesang Dhenub ◽  
Amelia Still ◽  
Eric Barklis
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Protein Assembly ◽  
Particle Assembly ◽  
Gag Protein ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Terminal Domains

ABSTRACT The nucleocapsid (NC) domains of retrovirus precursor Gag (PrGag) proteins play an essential role in virus assembly. Evidence suggests that NC binding to viral RNA promotes dimerization of PrGag capsid (CA) domains, which triggers assembly of CA N-terminal domains (NTDs) into hexamer rings that are interconnected by CA C-terminal domains. To examine the influence of dimerization on human immunodeficiency virus type 1 (HIV-1) Gag protein assembly in vitro, we analyzed the assembly properties of Gag proteins in which NC domains were replaced with cysteine residues that could be linked via chemical treatment. In accordance with the model that Gag protein pairing triggers assembly, we found that cysteine cross-linking or oxidation reagents induced the assembly of virus-like particles. However, efficient assembly also was observed to be temperature dependent or required the tethering of NTDs. Our results suggest a multistep pathway for HIV-1 Gag protein assembly. In the first step, Gag protein pairing through NC-RNA interactions or C-terminal cysteine linkage fosters dimerization. Next, a conformational change converts assembly-restricted dimers or small oligomers into assembly-competent ones. At the final stage, final particle assembly occurs, possibly through a set of larger intermediates.

scholarly journals Identification of a Structural Element in HIV-1 Gag Required for Virus Particle Assembly and Maturation

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Mariia Novikova ◽  
Lucas J. Adams ◽  
Juan Fontana ◽  
Anna T. Gres ◽  
Muthukumar Balasubramaniam ◽  
...  
Keyword(s):  
Virus Assembly ◽  
Critical Role ◽  
Replication Cycle ◽  
Structural Defects ◽  
Fold Axis ◽  
Structural Element ◽  
Particle Assembly ◽  
Compensatory Mutations ◽  
Hiv 1 ◽  
Selection Of

ABSTRACTLate in the HIV-1 replication cycle, the viral structural protein Gag is targeted to virus assembly sites at the plasma membrane of infected cells. The capsid (CA) domain of Gag plays a critical role in the formation of the hexameric Gag lattice in the immature virion, and, during particle release, CA is cleaved from the Gag precursor by the viral protease and forms the conical core of the mature virion. A highly conserved Pro-Pro-Ile-Pro (PPIP) motif (CA residues 122 to 125) [PPIP(122–125)] in a loop connecting CA helices 6 and 7 resides at a 3-fold axis formed by neighboring hexamers in the immature Gag lattice. In this study, we characterized the role of this PPIP(122–125) loop in HIV-1 assembly and maturation. While mutations P123A and P125A were relatively well tolerated, mutation of P122 and I124 significantly impaired virus release, caused Gag processing defects, and abolished infectivity. X-ray crystallography indicated that the P122A and I124A mutations induce subtle changes in the structure of the mature CA lattice which were permissive forin vitroassembly of CA tubes. Transmission electron microscopy and cryo-electron tomography demonstrated that the P122A and I124A mutations induce severe structural defects in the immature Gag lattice and abrogate conical core formation. Propagation of the P122A and I124A mutants in T-cell lines led to the selection of compensatory mutations within CA. Our findings demonstrate that the CA PPIP(122–125) loop comprises a structural element critical for the formation of the immature Gag lattice.IMPORTANCECapsid (CA) plays multiple roles in the HIV-1 replication cycle. CA-CA domain interactions are responsible for multimerization of the Gag polyprotein at virus assembly sites, and in the mature virion, CA monomers assemble into a conical core that encapsidates the viral RNA genome. Multiple CA regions that contribute to the assembly and release of HIV-1 particles have been mapped and investigated. Here, we identified and characterized a Pro-rich loop in CA that is important for the formation of the immature Gag lattice. Changes in this region disrupt viral production and abrogate the formation of infectious, mature virions. Propagation of the mutants in culture led to the selection of second-site compensatory mutations within CA. These results expand our knowledge of the assembly and maturation steps in the viral replication cycle and may be relevant for development of antiviral drugs targeting CA.

scholarly journals The Interplay between HIV-1 Gag Binding to the Plasma Membrane and Env Incorporation

Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 548 ◽  
Author(s):  
R. Elliot Murphy ◽  
Jamil S. Saad
Keyword(s):  
Plasma Membrane ◽  
Envelope Glycoprotein ◽  
Virus Production ◽  
Mortality Rates ◽  
Therapeutic Agents ◽  
Structural Level ◽  
Particle Assembly ◽  
Virus Particles ◽  
Molecular Determinants ◽  
Hiv 1

Advancement in drug therapies and patient care have drastically improved the mortality rates of HIV-1 infected individuals. Many of these therapies were developed or improved upon by using structure-based techniques, which underscore the importance of understanding essential mechanisms in the replication cycle of HIV-1 at the structural level. One such process which remains poorly understood is the incorporation of the envelope glycoprotein (Env) into budding virus particles. Assembly of HIV particles is initiated by targeting of the Gag polyproteins to the inner leaflet of the plasma membrane (PM), a process mediated by the N-terminally myristoylated matrix (MA) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). There is strong evidence that formation of the Gag lattice on the PM is a prerequisite for the incorporation of Env into budding particles. It is also suggested that Env incorporation is mediated by an interaction between its cytoplasmic tail (gp41CT) and the MA domain of Gag. In this review, we highlight the latest developments and current efforts to understand the interplay between gp41CT, MA, and the membrane during assembly. Elucidation of the molecular determinants of Gag–Env–membrane interactions may help in the development of new antiviral therapeutic agents that inhibit particle assembly, Env incorporation and ultimately virus production.

Assay of HIV-1 proteinase: A colorimetric method using small peptide substrates

1991 ◽  
Vol 193 (2) ◽  
pp. 280-286 ◽  
Author(s):  
Anne V. Broadhurst ◽  
Noel A. Roberts ◽  
Alison J. Ritchie ◽  
Balraj K. Handa ◽  
Corinne Kay
Keyword(s):  
Colorimetric Method ◽  
Small Peptide ◽  
Peptide Substrates ◽  
Proteinase A ◽  
Hiv 1

scholarly journals Kinesin KIF4 Regulates Intracellular Trafficking and Stability of the Human Immunodeficiency Virus Type 1 Gag Polyprotein

2008 ◽  
Vol 82 (20) ◽  
pp. 9937-9950 ◽  
Author(s):  
Nathaniel W. Martinez ◽  
Xiaoxiao Xue ◽  
Reem G. Berro ◽  
Geri Kreitzer ◽  
Marilyn D. Resh
Keyword(s):  
Human Immunodeficiency Virus ◽  
Plasma Membrane ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Particle Production ◽  
Particle Assembly ◽  
Gag Protein ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Retroviral Gag proteins are synthesized as soluble, myristoylated precursors that traffic to the plasma membrane and promote viral particle production. The intracellular transport of human immunodeficiency virus type 1 (HIV-1) Gag to the plasma membrane remains poorly understood, and cellular motor proteins responsible for Gag movement are not known. Here we show that disrupting the function of KIF4, a kinesin family member, slowed temporal progression of Gag through its trafficking intermediates and inhibited virus-like particle production. Knockdown of KIF4 also led to increased Gag degradation, resulting in reduced intracellular Gag protein levels; this phenotype was rescued by reintroduction of KIF4. When KIF4 function was blocked, Gag transiently accumulated in discrete, perinuclear, nonendocytic clusters that colocalized with endogenous KIF4, with Ubc9, an E2 SUMO-1 conjugating enzyme, and with SUMO. These studies identify a novel transit station through which Gag traffics en route to particle assembly and highlight the importance of KIF4 in regulating HIV-1 Gag trafficking and stability.

scholarly journals Analysis of HIV-1 subtype B third variable region peptide motifs for induction of neutralizing antibodies against HIV-1 primary isolates

Virology ◽  
2006 ◽  
Vol 345 (1) ◽  
pp. 44-55 ◽  
Author(s):  
Barton F. Haynes ◽  
Benjiang Ma ◽  
David C. Montefiori ◽  
Terri Wrin ◽  
Christos J. Petropoulos ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Variable Region ◽  
Peptide Motifs ◽  
Subtype B ◽  
Hiv 1

scholarly journals Interaction between the Human Immunodeficiency Virus Type 1 Gag Matrix Domain and Phosphatidylinositol-(4,5)-Bisphosphate Is Essential for Efficient Gag Membrane Binding

2007 ◽  
Vol 82 (5) ◽  
pp. 2405-2417 ◽  
Author(s):  
Vineela Chukkapalli ◽  
Ian B. Hogue ◽  
Vitaly Boyko ◽  
Wei-Shau Hu ◽  
Akira Ono
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Molecular Mechanisms ◽  
Membrane Binding ◽  
Particle Assembly ◽  
Immunodeficiency Virus ◽  
The Impact ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) particle assembly mediated by the viral structural protein Gag occurs predominantly on the plasma membrane (PM). Although it is known that the matrix (MA) domain of Gag plays a major role in PM localization, molecular mechanisms that determine the location of assembly remain to be elucidated. We observed previously that overexpression of polyphosphoinositide 5-phosphatase IV (5ptaseIV) that depletes PM phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] impairs virus particle production and redirects processed Gag to intracellular compartments. In this study, we examined the impact of PI(4,5)P2 depletion on the subcellular localization of the entire Gag population using Gag-fluorescent protein chimeras. Upon 5ptaseIV overexpression, in addition to perinuclear localization, Gag also showed a hazy cytosolic signal, suggesting that PI(4,5)P2 depletion impairs Gag membrane binding. Indeed, Gag was less membrane bound in PI(4,5)P2-depleted cells, as assessed by biochemical analysis. These observations are consistent with the hypothesis that Gag interacts with PI(4,5)P2. To examine a putative Gag interaction with PI(4,5)P2, we developed an in vitro binding assay using full-length myristoylated Gag and liposome-associated PI(4,5)P2. Using this assay, we observed that PI(4,5)P2 significantly enhances liposome binding of wild-type Gag. In contrast, a Gag derivative lacking MA did not require PI(4,5)P2 for efficient liposome binding. To analyze the involvement of MA in PI(4,5)P2 binding further, we examined MA basic amino acid substitution mutants. These mutants, previously shown to localize in perinuclear compartments, bound PI(4,5)P2-containing liposomes weakly. Altogether, these results indicate that HIV-1 Gag binds PI(4,5)P2 on the membrane and that the MA basic domain mediates this interaction.

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