Reduced cell surface expression of processed human immunodeficiency virus type 1 envelope glycoprotein in the presence of Nef.

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) accessory protein Vpu enhances virus particle release by counteracting a host factor that retains virions at the surfaces of infected cells. It was recently demonstrated that cellular protein BST-2/CD317/Tetherin restricts HIV-1 release in a Vpu-dependent manner. Calcium-modulating cyclophilin ligand (CAML) was also proposed to be involved in this process. We investigated whether CAML is involved in cell surface expression of Tetherin. Here, we show that CAML overexpression in permissive Cos-7 cells or CAML depletion in restrictive HeLa cells has no effect on HIV-1 release or on Tetherin surface expression, indicating that CAML is not required for Tetherin-mediated restriction of HIV-1 release.

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Identification of amino acids within the second alpha helical domain of the human immunodeficiency virus type 1 Vpu that are critical for preventing CD4 cell surface expression

Virology ◽

10.1016/j.virol.2009.10.048 ◽

2010 ◽

Vol 397 (1) ◽

pp. 104-112 ◽

Cited By ~ 10

Author(s):

M. Sarah Hill ◽

Autumn Ruiz ◽

Kimberly Schmitt ◽

Edward B. Stephens

Keyword(s):

Amino Acids ◽

Human Immunodeficiency Virus ◽

Cell Surface ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Surface Expression ◽

Cell Surface Expression ◽

Immunodeficiency Virus ◽

Cd4 Cell

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Costimulation of Naive CD8+ Lymphocytes Induces CD4 Expression and Allows Human Immunodeficiency Virus Type 1 Infection

Journal of Virology ◽

10.1128/jvi.72.11.9054-9060.1998 ◽

1998 ◽

Vol 72 (11) ◽

pp. 9054-9060 ◽

Cited By ~ 95

Author(s):

Scott G. Kitchen ◽

Yael D. Korin ◽

Michael D. Roth ◽

Alan Landay ◽

Jerome A. Zack

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Surface Expression ◽

Cell Surface Expression ◽

Rapid Disease Progression ◽

Cd8 Cells ◽

Immunodeficiency Virus ◽

Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection requires cell surface expression of CD4. Costimulation of CD8+/CD4− T lymphocytes by anti-CD3 and anti-CD28 antibodies or by allogeneic dendritic cells induced expression of CD4 and rendered these CD8 cells susceptible to HIV-1 infection. Naive CD45RA+ cells responded with greater expression of CD4 than did CD45RO+ cells. CD8+lymphocytes derived from fetal or newborn sources exhibited a greater tendency to express CD4, consistent with their naive states. This mechanism of infection suggests HIV-induced perturbation of the CD8 arm of the immune response and could explain the generally rapid disease progression seen in HIV-infected children.

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Identification of Two Sequences in the Cytoplasmic Tail of the Human Immunodeficiency Virus Type 1 Envelope Glycoprotein That Inhibit Cell Surface Expression

Journal of Virology ◽

10.1128/jvi.75.11.5263-5276.2001 ◽

2001 ◽

Vol 75 (11) ◽

pp. 5263-5276 ◽

Cited By ~ 52

Author(s):

Andreas Bültmann ◽

Walter Muranyi ◽

Brian Seed ◽

Jürgen Haas

Keyword(s):

Amino Acids ◽

Human Immunodeficiency Virus ◽

Cell Surface ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Surface Expression ◽

Immunodeficiency Virus ◽

Sequence Elements ◽

Env Glycoprotein

ABSTRACT During synthesis and export of protein, the majority of the human immunodeficiency virus type 1 (HIV-1) Env glycoprotein gp160 is retained in the endoplasmic reticulum (ER) and subsequently ubiquitinated and degraded by proteasomes. Only a small fraction of gp160 appears to be correctly folded and processed and is transported to the cell surface, which makes it difficult to identify negative sequence elements regulating steady-state surface expression of Env at the post-ER level. Moreover, poorly localized mRNA retention sequences inhibiting the nucleocytoplasmic transport of viral transcripts interfere with the identification of these sequence elements. Using two heterologous systems with CD4 or immunoglobulin extracellular/transmembrane domains in combination with the gp160 cytoplasmic domain, we were able to identify two membrane-distal, neighboring motifs, is1 (amino acids 750 to 763) andis2 (amino acids 764 to 785), which inhibited surface expression and induced Golgi localization of the chimeric proteins. To prove that these two elements act similarly in the homologous context of the Env glycoprotein, we generated a synthetic gp160 gene with synonymous codons, the transcripts of which are not retained within the nucleus. In accordance with the results in heterologous systems, an internal deletion of both elements considerably increased surface expression of gp160.

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The Crown and Stem of the V3 Loop Play Distinct Roles in Human Immunodeficiency Virus Type 1 Envelope Glycoprotein Interactions with the CCR5 Coreceptor

Journal of Virology ◽

10.1128/jvi.76.17.8953-8957.2002 ◽

2002 ◽

Vol 76 (17) ◽

pp. 8953-8957 ◽

Cited By ~ 189

Author(s):

Emmanuel G. Cormier ◽

Tatjana Dragic

Keyword(s):

Human Immunodeficiency Virus ◽

Cell Surface ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Viral Entry ◽

Envelope Glycoprotein ◽

V3 Loop ◽

Gp120 Binding ◽

Immunodeficiency Virus

ABSTRACT Human immunodeficiency virus type 1 envelope glycoprotein gp120 interacts with CD4 and the CCR5 coreceptor in order to mediate viral entry. A CD4-induced surface on gp120, primarily composed of residues in the V3 loop and the C4 domain, interacts with CCR5. In the present study, we generated envelope glycoproteins comprising chimeric V3 loops and/or V3 loops with deletions and studied their binding to CCR5 amino-terminal domain (Nt)-based sulfopeptides and cell surface CCR5, as well as their ability to mediate viral entry. We thus delineated two functionally distinct domains of the V3 loop, the V3 stem and the V3 crown. The V3 stem alone mediates soluble gp120 binding to the CCR5 Nt. In contrast, both the V3 stem and crown are required for soluble gp120 binding to cell surface CCR5. Within the context of a virion, however, the V3 crown alone determines coreceptor usage. Our data support a two-site gp120-CCR5 binding model wherein the V3 crown and stem interact with distinct regions of CCR5 in order to mediate viral entry.

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