Structure and Function of the Human Immunodeficiency Virus Type 1

1992 ◽  
Vol 12 (02) ◽  
pp. 103-107 ◽  
Author(s):  
George Pavlakis
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Structure And Function ◽  
Immunodeficiency Virus ◽  
And Function

scholarly journals Induction of G2 Arrest and Binding to Cyclophilin A Are Independent Phenotypes of Human Immunodeficiency Virus Type 1 Vpr

2006 ◽  
Vol 80 (8) ◽  
pp. 3694-3700 ◽  
Author(s):  
Orly Ardon ◽  
Erik S. Zimmerman ◽  
Joshua L. Andersen ◽  
Jason L. DeHart ◽  
Jana Blackett ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cyclophilin A ◽  
Induce Cell Cycle Arrest ◽  
Ppiase Activity ◽  
Immunodeficiency Virus ◽  
Steady State Levels ◽  
And Function

ABSTRACT Cyclophilin A (CypA) is a member of a family of cellular proteins that share a peptidyl prolyl cis-trans isomerase (PPIase) activity. CypA was previously reported to be required for the biochemical stability and function (specifically, induction of G2 arrest) of the human immunodeficiency virus type 1 (HIV-1) protein R (Vpr). In the present study, we examine the role of the Vpr-CypA interaction on Vpr-induced G2 arrest. We find that Vpr coimmunoprecipitates with CypA and that this interaction is disrupted by substitution of proline-35 of Vpr as well as incubation with the CypA inhibitor cyclosporine A (CsA). Surprisingly, the presence of CypA or its binding to Vpr is dispensable for the ability of Vpr to induce G2 arrest. Vpr expression in CypA−/− cells leads to induction of G2 arrest in a manner that is indistinguishable from that in CypA+ cells. CsA abolished CypA-Vpr binding but had no effect on induction of G2 arrest or Vpr steady-state levels. In view of these results, we propose that the interaction with CypA is independent of the ability of Vpr to induce cell cycle arrest. The interaction between Vpr and CypA is intriguing, and further studies should examine its potential effects on other functions of Vpr.

A Synthetic Peptide Derived From Human Immunodeficiency Virus Type 1 gp120 Downregulates the Expression and Function of Chemokine Receptors CCR5 and CXCR4 in Monocytes by Activating the 7-Transmembrane G-Protein–Coupled Receptor FPRL1/LXA4R

Blood ◽  
1999 ◽  
Vol 94 (4) ◽  
pp. 1165-1173
Author(s):  
Xiyun Deng ◽  
Hirotsugu Ueda ◽  
Shao Bo Su ◽  
Wanghua Gong ◽  
Nancy M. Dunlop ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
G Protein ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Synthetic Peptide ◽  
Immunodeficiency Virus ◽  
And Function ◽  
G Protein Coupled ◽  
Hiv 1

Because envelope gp120 of various strains of human immunodeficiency virus type 1 (HIV-1) downregulates the expression and function of a variety of chemoattractant receptors through a process of heterologous desensitization, we investigated whether epitopes derived from gp120 could mimic the effect. A synthetic peptide domain, designated F peptide, corresponding to amino acid residues 414-434 in the V4-C4 region of gp120 of the HIV-1 Bru strain, potently reduced monocyte binding and chemotaxis response to macrophage inflammatory protein 1β (MIP-1β) and stromal cell-derived factor 1 (SDF-1), chemokines that use the receptors CCR5 and CXCR4, respectively. Further study showed that F peptide by itself is an inducer of chemotaxis and calcium mobilization in human monocytes and neutrophils. In cross-desensitization experiments, among the numerous chemoattractants tested, only the bacterial chemotactic peptide fMLF, when used at high concentrations, partially attenuated calcium mobilization induced by F peptide in phagocytes, suggesting that this peptide domain might share a 7-transmembrane, G-protein–coupled receptor with fMLF. By using cells transfected with cDNAs encoding receptors that interact with fMLF, we found that F peptide uses an fMLF receptor variant, FPRL1, as a functional receptor. The activation of monocytes by F peptide resulted in downregulation of the cell surface expression of CCR5 and CXCR4 in a protein kinase C-dependent manner. These results demonstrate that activation of FPRL1 on human moncytes by a peptide domain derived from HIV-1 gp120 could lead to desensitization of cell response to other chemoattractants. This may explain, at least in part, the initial activation of innate immune responses in HIV-1–infected patients followed by immune suppression.

scholarly journals Expression and Function of Chemokine Receptors on Human Thymocytes: Implications for Infection by Human Immunodeficiency Virus Type 1

2001 ◽  
Vol 75 (18) ◽  
pp. 8752-8760 ◽  
Author(s):  
James R. Taylor ◽  
Katherine C. Kimbrell ◽  
Robert Scoggins ◽  
Marie Delaney ◽  
Lijun Wu ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Chemokine Receptors ◽  
Cross Reactivity ◽  
Immunodeficiency Virus ◽  
Chemokine Ligands ◽  
And Function ◽  
Hiv 1

ABSTRACT The presence or absence of the receptor CD4 and the coreceptors CCR5 and CXCR4 restrict the cell tropism of human immunodeficiency virus type 1 (HIV-1). Despite the importance of thymic infection by HIV-1, conflicting reports regarding the expression of HIV-1 coreceptors on human thymocytes have not been resolved. We assayed the expression and function of the major HIV-1 coreceptors, CCR5 and CXCR4, as well as CCR4 and CCR7 as controls, on human thymocytes. We detected CCR5 on 2.5% of thymocytes, CXCR4 on 53% of the cells, and CCR4 on 16% and CCR7 on 11% of human thymocytes. Moreover, infection by R5 HIV-1 did not significantly induce expression of CCR5. We found that two widely used anti-CCR5 monoclonal antibodies cross-reacted with CCR8, which may account for discrepancies among published reports of CCR5 expression on primary cells. This cross-reactivity could be eliminated by deletion of amino acids 2 through 4 of CCR8. Chemotaxis assays showed that SDF-1, which binds CXCR4; MDC, which binds CCR4; and ELC, which binds CCR7, mediated significant chemotaxis of thymocytes. In contrast, MIP-1β, whose receptor is CCR5, did not induce significant chemotaxis. Our results indicate that CXCR4, CCR4, CCR7, and their chemokine ligands may be involved in thymocyte migration during development in the thymus. CCR5 and its ligands, however, are likely not involved in these processes. Furthermore, the pattern of CCR5 and CXCR4 expression that we found may explain the greater susceptibility of human thymocytes to infection by HIV-1 isolates capable of using CXCR4 in cell entry compared to those that use only CCR5.

scholarly journals Clade-Specific Differences between Human Immunodeficiency Virus Type 1 Clades B and C: Diversity and Correlations in C3-V4 Regions of gp120

2007 ◽  
Vol 81 (9) ◽  
pp. 4886-4891 ◽  
Author(s):  
S. Gnanakaran ◽  
Dorothy Lang ◽  
Marcus Daniels ◽  
Tanmoy Bhattacharya ◽  
Cynthia A. Derdeyn ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Current Knowledge ◽  
Viral Glycoprotein ◽  
Clade B ◽  
Immunodeficiency Virus ◽  
Clade C ◽  
And Function

ABSTRACT Current knowledge of human immunodeficiency virus type 1 envelope (Env) glycoprotein structure and function is based on studies of clade B viruses. We present evidence of sequence and structural differences in viral glycoprotein gp120 between clades B and C. In clade C, the C3 region α2-helix exhibits high sequence entropy at the polar face but maintains its amphipathicity, whereas in clade B it accommodates hydrophobic residues. The V4 hypervariable domain in clade C is shorter than that in clade B. Generally, shorter V4 loops are incompatible with a glycine occurring in the α2-helix in clade C, an intriguing association that could be exploited to inform Env immunogen design.

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