Correction: Plasma Membrane Is the Site of Productive HIV-1 Particle Assembly

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.

Download Full-text

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

Journal of Virology ◽

10.1128/jvi.00819-08 ◽

2008 ◽

Vol 82 (20) ◽

pp. 9937-9950 ◽

Cited By ~ 54

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.

Download Full-text

Full assembly of HIV-1 particles requires assistance of the membrane curvature factor IRSp53

eLife ◽

10.7554/elife.67321 ◽

2021 ◽

Vol 10 ◽

Author(s):

Kaushik Inamdar ◽

Feng-Ching Tsai ◽

Rayane Dibsy ◽

Aurore de Poret ◽

John Manzi ◽

...

Keyword(s):

Plasma Membrane ◽

Single Molecule ◽

Particle Production ◽

Virus Assembly ◽

Membrane Curvature ◽

Particle Assembly ◽

Gag Protein ◽

Cell Plasma ◽

Curved Membranes ◽

Hiv 1

During HIV-1 particle formation, the requisite plasma membrane curvature is thought to be solely driven by the retroviral Gag protein. Here, we reveal that the cellular I-BAR protein IRSp53 is required for the progression of HIV-1 membrane curvature to complete particle assembly. SiRNA-mediated knockdown of IRSp53 gene expression induces a decrease in viral particle production and a viral bud arrest at half completion. Single molecule localization microscopy at the cell plasma membrane shows a preferential localization of IRSp53 around HIV-1 Gag assembly sites. In addition, we observe the presence of IRSp53 in purified HIV-1 particles. Finally, HIV-1 Gag protein preferentially localizes to curved membranes induced by IRSp53 I-BAR domain on giant unilamellar vesicles. Overall, our data reveal a strong interplay between IRSp53 I-BAR and Gag at membranes during virus assembly. This highlights IRSp53 as a crucial host factor in HIV-1 membrane curvature and its requirement for full HIV-1 particle assembly.

Download Full-text

Faculty Opinions recommendation of Plasma membrane is the site of productive HIV-1 particle assembly.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1054012.505975 ◽

2006 ◽

Author(s):

Vojo Deretic

Keyword(s):

Plasma Membrane ◽

Particle Assembly ◽

Hiv 1

Download Full-text

Plasma Membrane Anchoring and Gag:Gag Multimerization on Viral RNA Are Critical Properties of HIV-1 Gag Required To Mediate Efficient Genome Packaging

mBio ◽

10.1128/mbio.03254-21 ◽

2021 ◽

Author(s):

Alice Duchon ◽

Steven Santos ◽

Jianbo Chen ◽

Matthew Brown ◽

Olga A. Nikolaitchik ◽

...

Keyword(s):

Plasma Membrane ◽

Full Length ◽

Viral Rna ◽

Critical Properties ◽

Genome Packaging ◽

Particle Assembly ◽

Membrane Anchoring ◽

Hiv 1

To generate infectious virions, HIV-1 must package its full-length RNA as the genome during particle assembly. HIV-1 Gag:RNA interactions mediate genome packaging, but the mechanism remains unclear.

Download Full-text

Productive Human Immunodeficiency Virus Type 1 Assembly Takes Place at the Plasma Membrane

Journal of Virology ◽

10.1128/jvi.00308-07 ◽

2007 ◽

Vol 81 (14) ◽

pp. 7476-7490 ◽

Cited By ~ 75

Author(s):

Andrés Finzi ◽

Alexandre Orthwein ◽

Johanne Mercier ◽

Éric A. Cohen

Keyword(s):

Human Immunodeficiency Virus ◽

Plasma Membrane ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Multivesicular Body ◽

Subcellular Fractionation ◽

Particle Assembly ◽

Immunodeficiency Virus ◽

Hiv 1

ABSTRACT Gag proteins are necessary and sufficient to direct human immunodeficiency virus type 1 (HIV-1) particle assembly and budding. Recent evidence suggests that Gag targeting to late endosomal/multivesicular body (LE/MVB) compartments occurs prior to viral particle budding at the plasma membrane (PM). However, the route that Gag follows before reaching its steady-state destinations still remains a subject of debate. Using a subcellular fractionation method that separates PM from LE/MVB combined with pulse-chase labeling, we analyzed Gag trafficking in HIV-1-producing HEK 293T cells. Our results reveal that the majority of newly synthesized Gag is primarily targeted to the PM. While PM-targeted Gag was efficiently released, a significant fraction of the remaining cell surface-associated Gag was found to be subsequently internalized to LE/MVB, where it accumulated, thus accounting for the majority of LE/MVB-associated Gag. Importantly, this accumulation of Gag in LE/MVB was found to be cholesterol dependent since it was sensitive to the sterol-binding drugs filipin and methyl-β-cyclodextrin. These results point towards the PM as being the primary site of productive HIV-1 assembly in cells that also support Gag accumulation in intracellular compartments.

Download Full-text

Plasma Membrane Is the Site of Productive HIV-1 Particle Assembly

PLoS Biology ◽

10.1371/journal.pbio.0040435 ◽

2006 ◽

Vol 4 (12) ◽

pp. e435 ◽

Cited By ~ 246

Author(s):

Nolwenn Jouvenet ◽

Stuart J. D Neil ◽

Cameron Bess ◽

Marc C Johnson ◽

Cesar A Virgen ◽

...

Keyword(s):

Plasma Membrane ◽

Particle Assembly ◽

Hiv 1

Download Full-text

HIV-1 Envelope Glycoprotein Trafficking through the Endosomal Recycling Compartment Is Required for Particle Incorporation

Journal of Virology ◽

10.1128/jvi.01893-17 ◽

2017 ◽

Vol 92 (5) ◽

Cited By ~ 16

Author(s):

Junghwa Kirschman ◽

Mingli Qi ◽

Lingmei Ding ◽

Jason Hammonds ◽

Krista Dienger-Stambaugh ◽

...

Keyword(s):

Plasma Membrane ◽

Envelope Glycoprotein ◽

Envelope Protein ◽

Cytoplasmic Tail ◽

Particle Assembly ◽

Endosomal Recycling ◽

Immunodeficiency Virus ◽

Particle Incorporation ◽

Hiv Envelope ◽

Hiv 1

ABSTRACTThe human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) encodes specific trafficking signals within its long cytoplasmic tail (CT) that regulate incorporation into HIV-1 particles. Rab11-family interacting protein 1C (FIP1C) and Rab14 are host trafficking factors required for Env particle incorporation, suggesting that Env undergoes sorting from the endosomal recycling compartment (ERC) to the site of particle assembly on the plasma membrane. We disrupted outward sorting from the ERC by expressing a C-terminal fragment of FIP1C (FIP1C560–649) and examined the consequences on Env trafficking and incorporation into particles. FIP1C560–649reduced cell surface levels of Env and prevented its incorporation into HIV-1 particles. Remarkably, Env was trapped in an exaggerated perinuclear ERC in a CT-dependent manner. Mutation of either the Yxxϕ endocytic motif or the YW795motif in the CT prevented Env trapping in the ERC and restored incorporation into particles. In contrast, simian immunodeficiency virus SIVmac239 Env was not retained in the ERC, while substitution of the HIV-1 CT for the SIV CT resulted in SIV Env retention in this compartment. These results provide the first direct evidence that Env traffics through the ERC and support a model whereby HIV-1 Env is specifically targeted to the ERC prior to FIP1C- and CT-dependent outward sorting to the particle assembly site on the plasma membrane.IMPORTANCEThe HIV envelope protein is an essential component of the viral particle. While many aspects of envelope protein structure and function have been established, the pathway it follows in the cell prior to reaching the site of particle assembly is not well understood. The envelope protein has a very long cytoplasmic tail that interacts with the host cell trafficking machinery. Here, we utilized a truncated form of the trafficking adaptor FIP1C protein to arrest the intracellular transport of the envelope protein, demonstrating that it becomes trapped inside the cell within the endosomal recycling compartment. Intracellular trapping resulted in a loss of envelope protein on released particles and a corresponding loss of infectivity. Mutations of specific trafficking motifs in the envelope protein tail prevented its trapping in the recycling compartment. These results establish that trafficking to the endosomal recycling compartment is an essential step in HIV envelope protein particle incorporation.

Download Full-text

Full assembly of HIV-1 particles requires assistance of the membrane curvature factor IRSp53

10.1101/2021.02.10.430663 ◽

2021 ◽

Author(s):

Kaushik Inamdar ◽

Feng-Ching Tsai ◽

Aurore de Poret ◽

Rayane Dibsy ◽

John Manzi ◽

...

Keyword(s):

Plasma Membrane ◽

Single Molecule ◽

Particle Production ◽

Virus Assembly ◽

Membrane Curvature ◽

Particle Assembly ◽

Gag Protein ◽

Cell Plasma ◽

Curved Membranes ◽

Hiv 1

During HIV-1 particle formation, the requisite plasma membrane curvature is thought to be solely driven by the retroviral Gag protein. Here, we reveal that the cellular I-BAR protein IRSp53 is required for the progression of HIV-1 membrane curvature to complete particle assembly. Partial gene editing of IRSp53 induces a decrease in viral particle production and a viral bud arrest at half completion. Single molecule localization microscopy at the cell plasma membrane shows a preferential localization of IRSp53 around HIV-1 Gag assembly sites. In addition, we observe the presence of IRSp53 in purified HIV-1 particles. Finally, HIV-1 Gag protein localizes preferentially to IRSp53 I-BAR domain induced curved membranes on giant unilamellar vesicles. Overall, our data reveal a strong interplay between IRSp53 I-BAR and Gag at membranes during virus assembly. This highlights IRSp53 as a crucial host factor in HIV-1 membrane curvature and its requirement for full HIV-1 particle assembly.

Download Full-text

Dynamic Association between HIV-1 Gag and Membrane Domains

Molecular Biology International ◽

10.1155/2012/979765 ◽

2012 ◽

Vol 2012 ◽

pp. 1-13 ◽

Cited By ~ 12

Author(s):

Ian B. Hogue ◽

G. Nicholas Llewellyn ◽

Akira Ono

Keyword(s):

Plasma Membrane ◽

Virus Assembly ◽

Active Role ◽

Spherical Particles ◽

Cell Junction ◽

Membrane Microdomains ◽

Virological Synapse ◽

Structural Protein ◽

Particle Assembly ◽

Hiv 1

HIV-1 particle assembly is driven by the structural protein Gag. Gag binds to and multimerizes on the inner leaflet of the plasma membrane, eventually resulting in formation of spherical particles. During virus spread among T cells, Gag accumulates to the plasma membrane domain that, together with target cell membrane, forms a cell junction known as the virological synapse. While Gag association with plasma membrane microdomains has been implicated in virus assembly and cell-to-cell transmission, recent studies suggest that, rather than merely accumulating to pre-existing microdomains, Gag plays an active role in reorganizing the microdomains via its multimerization activity. In this paper, we will discuss this emerging view of Gag microdomain interactions. Relationships between Gag multimerization and microdomain association will be further discussed in the context of Gag localization to T-cell uropods and virological synapses.

Download Full-text