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Nickoloff-Bybel EA, Festa L, Meucci O, Gaskill PJ. Co-receptor signaling in the pathogenesis of neuroHIV. Retrovirology 2021; 18:24. [PMID: 34429135 PMCID: PMC8385912 DOI: 10.1186/s12977-021-00569-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022] Open
Abstract
The HIV co-receptors, CCR5 and CXCR4, are necessary for HIV entry into target cells, interacting with the HIV envelope protein, gp120, to initiate several signaling cascades thought to be important to the entry process. Co-receptor signaling may also promote the development of neuroHIV by contributing to both persistent neuroinflammation and indirect neurotoxicity. But despite the critical importance of CXCR4 and CCR5 signaling to HIV pathogenesis, there is only one therapeutic (the CCR5 inhibitor Maraviroc) that targets these receptors. Moreover, our understanding of co-receptor signaling in the specific context of neuroHIV is relatively poor. Research into co-receptor signaling has largely stalled in the past decade, possibly owing to the complexity of the signaling cascades and functions mediated by these receptors. Examining the many signaling pathways triggered by co-receptor activation has been challenging due to the lack of specific molecular tools targeting many of the proteins involved in these pathways and the wide array of model systems used across these experiments. Studies examining the impact of co-receptor signaling on HIV neuropathogenesis often show activation of multiple overlapping pathways by similar stimuli, leading to contradictory data on the effects of co-receptor activation. To address this, we will broadly review HIV infection and neuropathogenesis, examine different co-receptor mediated signaling pathways and functions, then discuss the HIV mediated signaling and the differences between activation induced by HIV and cognate ligands. We will assess the specific effects of co-receptor activation on neuropathogenesis, focusing on neuroinflammation. We will also explore how the use of substances of abuse, which are highly prevalent in people living with HIV, can exacerbate the neuropathogenic effects of co-receptor signaling. Finally, we will discuss the current state of therapeutics targeting co-receptors, highlighting challenges the field has faced and areas in which research into co-receptor signaling would yield the most therapeutic benefit in the context of HIV infection. This discussion will provide a comprehensive overview of what is known and what remains to be explored in regard to co-receptor signaling and HIV infection, and will emphasize the potential value of HIV co-receptors as a target for future therapeutic development. ![]()
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Affiliation(s)
- E A Nickoloff-Bybel
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - L Festa
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, 240 S. 40th Street, Philadelphia, PA, 19104, USA
| | - O Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.,Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, 19102, USA
| | - P J Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.
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2
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Chen L, Keppler OT, Schölz C. Post-translational Modification-Based Regulation of HIV Replication. Front Microbiol 2018; 9:2131. [PMID: 30254620 PMCID: PMC6141784 DOI: 10.3389/fmicb.2018.02131] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/20/2018] [Indexed: 12/13/2022] Open
Abstract
Human immunodeficiency virus (HIV) relies heavily on the host cellular machinery for production of viral progeny. To exploit cellular proteins for replication and to overcome host factors with antiviral activity, HIV has evolved a set of regulatory and accessory proteins to shape an optimized environment for its replication and to facilitate evasion from the immune system. Several cellular pathways are hijacked by the virus to modulate critical steps during the viral life cycle. Thereby, post-translational modifications (PTMs) of viral and cellular proteins gain increasingly attention as modifying enzymes regulate virtually every step of the viral replication cycle. This review summarizes the current knowledge of HIV-host interactions influenced by PTMs with a special focus on acetylation, ubiquitination, and phosphorylation of proteins linked to cellular signaling and viral replication. Insights into these interactions are surmised to aid development of new intervention strategies.
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Affiliation(s)
- Lin Chen
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Oliver T Keppler
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Christian Schölz
- Max von Pettenkofer-Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
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3
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Taylor HE, Simmons GE, Mathews TP, Khatua AK, Popik W, Lindsley CW, D’Aquila RT, Brown HA. Phospholipase D1 Couples CD4+ T Cell Activation to c-Myc-Dependent Deoxyribonucleotide Pool Expansion and HIV-1 Replication. PLoS Pathog 2015; 11:e1004864. [PMID: 26020637 PMCID: PMC4447393 DOI: 10.1371/journal.ppat.1004864] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/07/2015] [Indexed: 12/25/2022] Open
Abstract
Quiescent CD4+ T cells restrict human immunodeficiency virus type 1 (HIV-1) infection at early steps of virus replication. Low levels of both deoxyribonucleotide triphosphates (dNTPs) and the biosynthetic enzymes required for their de novo synthesis provide one barrier to infection. CD4+ T cell activation induces metabolic reprogramming that reverses this block and facilitates HIV-1 replication. Here, we show that phospholipase D1 (PLD1) links T cell activation signals to increased HIV-1 permissivity by triggering a c-Myc-dependent transcriptional program that coordinates glucose uptake and nucleotide biosynthesis. Decreasing PLD1 activity pharmacologically or by RNA interference diminished c-Myc-dependent expression during T cell activation at the RNA and protein levels. PLD1 inhibition of HIV-1 infection was partially rescued by adding exogenous deoxyribonucleosides that bypass the need for de novo dNTP synthesis. Moreover, the data indicate that low dNTP levels that impact HIV-1 restriction involve decreased synthesis, and not only increased catabolism of these nucleotides. These findings uncover a unique mechanism of action for PLD1 inhibitors and support their further development as part of a therapeutic combination for HIV-1 and other viral infections dependent on host nucleotide biosynthesis.
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Affiliation(s)
- Harry E. Taylor
- Northwestern HIV Translational Research Center, Division of Infectious Diseases, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- * E-mail: (HET); (HAB)
| | - Glenn E. Simmons
- Department of Molecular Genetics, University of Texas, Southwestern Medical Center, Dallas, Texas, United States of America
| | - Thomas P. Mathews
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Atanu K. Khatua
- Meharry Medical College, Center for AIDS Health Disparities Research, Nashville, Tennessee, United States of America
| | - Waldemar Popik
- Meharry Medical College, Center for AIDS Health Disparities Research, Nashville, Tennessee, United States of America
| | - Craig W. Lindsley
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Chemistry, Vanderbilt University, Nashville, Tennesee, United States of America
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Richard T. D’Aquila
- Northwestern HIV Translational Research Center, Division of Infectious Diseases, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - H. Alex Brown
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail: (HET); (HAB)
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4
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Duquenne C, Psomas C, Gimenez S, Guigues A, Carles MJ, Barbuat C, Lavigne JP, Sotto A, Reynes J, Guglielmi P, Mettling C, François V, Corbeau P. The two human CXCR4 isoforms display different HIV receptor activities: consequences for the emergence of X4 strains. THE JOURNAL OF IMMUNOLOGY 2014; 193:4188-94. [PMID: 25230750 DOI: 10.4049/jimmunol.1303298] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CXCR4 is a chemokine receptor that plays key roles with its specific ligand, CXCL12, in stem cell homing and immune trafficking. It is also used as a coreceptor by some HIV-1 strains (X4 strains), whereas other strains (R5 strains) use an alternative coreceptor, CCR5. X4 strains mainly emerge at late stages of the infection and are linked to disease progression. Two isoforms of this coreceptor have been described in humans: CXCR4-A and CXCR4-B, corresponding to an unspliced and a spliced mRNA, respectively. In this study, we show that CXCR4-B, but not CXCR4-A, mediates an efficient HIV-1 X4 entry and productive infection. Yet, the chemotactic activity of CXCL12 on both isoforms was similar. Furthermore, HIV-R5 infection favored CXCR4-B expression over that of CXCR4-A. In vitro infection with an R5 strain increased CXCR4-B/CXCR4-A mRNA ratio in PBMCs, and this ratio correlated with HIV RNA plasma level in R5-infected individuals. In addition, the presence of the CXCR4-B isoform favored R5 to X4 switch more efficiently than did CXCR4-A in vitro. Hence, the predominance of CXCR4-B over CXCR4-A expression in PBMCs was linked to the ability of circulating HIV-1 strains to use CXCR4, as determined by genotyping. These data suggest that R5 to X4 switch could be favored by R5 infection-induced overexpression of CXCR4-B. Finally, we achieved a specific small interfering RNA-mediated knockdown of CXCR4-B. This represents a proof of concept for a possible gene-therapeutic approach aimed at blocking the HIV coreceptor activity of CXCR4 without knocking down its chemotactic activity.
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Affiliation(s)
- Charline Duquenne
- Institut de Génétique Humaine, Unité Propre de Recherche 1142 du Centre National de la Recherche Scientifique, 34396 Montpellier Cedex 5, France
| | - Christina Psomas
- Infectious Diseases Department, Montpellier University Hospital, 34295 Montpellier Cedex 5, France; Unité Mixte Internationale 233, Institut de Recherche pour le Développement-Université Montpellier 1, 34294 Montpellier Cedex 5, France
| | - Sandrine Gimenez
- Institut de Génétique Humaine, Unité Propre de Recherche 1142 du Centre National de la Recherche Scientifique, 34396 Montpellier Cedex 5, France
| | - Adeline Guigues
- Institut de Génétique Humaine, Unité Propre de Recherche 1142 du Centre National de la Recherche Scientifique, 34396 Montpellier Cedex 5, France
| | - Marie-Josée Carles
- Microbiology Department, Nîmes University Hospital, 30029 Nîmes Cedex 9, France
| | - Claudine Barbuat
- Infectious Diseases Department, Nîmes University Hospital, 30029 Nîmes Cedex 9, France
| | - Jean-Philippe Lavigne
- Microbiology Department, Nîmes University Hospital, 30029 Nîmes Cedex 9, France; Faculté de Médecine, Université Montpellier 1, 34967 Montpellier Cedex 2, France; INSERM U1047, 30908 Nîmes Cedex 9, France
| | - Albert Sotto
- Infectious Diseases Department, Nîmes University Hospital, 30029 Nîmes Cedex 9, France; Faculté de Médecine, Université Montpellier 1, 34967 Montpellier Cedex 2, France; INSERM U1047, 30908 Nîmes Cedex 9, France
| | - Jacques Reynes
- Infectious Diseases Department, Montpellier University Hospital, 34295 Montpellier Cedex 5, France; Unité Mixte Internationale 233, Institut de Recherche pour le Développement-Université Montpellier 1, 34294 Montpellier Cedex 5, France; Faculté de Médecine, Université Montpellier 1, 34967 Montpellier Cedex 2, France
| | - Paul Guglielmi
- Unité Mixte de Recherche 5235, Centre National de la Recherche Scientifique-Université Montpellier 2, 34095 Montpellier, France; and
| | - Clément Mettling
- Institut de Génétique Humaine, Unité Propre de Recherche 1142 du Centre National de la Recherche Scientifique, 34396 Montpellier Cedex 5, France
| | - Vincent François
- Institut de Génétique Humaine, Unité Propre de Recherche 1142 du Centre National de la Recherche Scientifique, 34396 Montpellier Cedex 5, France
| | - Pierre Corbeau
- Institut de Génétique Humaine, Unité Propre de Recherche 1142 du Centre National de la Recherche Scientifique, 34396 Montpellier Cedex 5, France; Faculté de Médecine, Université Montpellier 1, 34967 Montpellier Cedex 2, France; Immunology Department, Nîmes University Hospital, 30029 Nîmes Cedex 9, France
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5
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Flanagan CA. Receptor Conformation and Constitutive Activity in CCR5 Chemokine Receptor Function and HIV Infection. ADVANCES IN PHARMACOLOGY 2014; 70:215-63. [DOI: 10.1016/b978-0-12-417197-8.00008-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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6
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Markle TJ, Philip M, Brockman MA. HIV-1 Nef and T-cell activation: a history of contradictions. Future Virol 2013; 8. [PMID: 24187576 DOI: 10.2217/fvl.13.20] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
HIV-1 Nef is a multifunctional viral protein that contributes to higher plasma viremia and more rapid disease progression. Nef appears to accomplish this, in part, through modulation of T-cell activation; however, the results of these studies over the past 25 years have been inconsistent. Here, the history of contradictory observations related to HIV-1 Nef and its ability to modulate T-cell activation is reviewed, and recent reports that may help to explain Net's apparent ability to both inhibit and activate T cells are highlighted.
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Affiliation(s)
- Tristan J Markle
- Simon Fraser University, 8888 University Drive, Burnaby BC V5A 1S6, Canada
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Use of G-protein-coupled and -uncoupled CCR5 receptors by CCR5 inhibitor-resistant and -sensitive human immunodeficiency virus type 1 variants. J Virol 2013; 87:6569-81. [PMID: 23468486 DOI: 10.1128/jvi.00099-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Small-molecule CCR5 inhibitors such as vicriviroc (VVC) and maraviroc (MVC) are allosteric modulators that impair HIV-1 entry by stabilizing a CCR5 conformation that the virus recognizes inefficiently. Viruses resistant to these compounds are able to bind the inhibitor-CCR5 complex while also interacting with the free coreceptor. CCR5 also interacts intracellularly with G proteins, as part of its signal transduction functions, and this process alters its conformation. Here we investigated whether the action of VVC against inhibitor-sensitive and -resistant viruses is affected by whether or not CCR5 is coupled to G proteins such as Gαi. Treating CD4(+) T cells with pertussis toxin to uncouple the Gαi subunit from CCR5 increased the potency of VVC against the sensitive viruses and revealed that VVC-resistant viruses use the inhibitor-bound form of Gαi-coupled CCR5 more efficiently than they use uncoupled CCR5. Supportive evidence was obtained by expressing a signaling-deficient CCR5 mutant with an impaired ability to bind to G proteins, as well as two constitutively active mutants that activate G proteins in the absence of external stimuli. The implication of these various studies is that the association of intracellular domains of CCR5 with the signaling machinery affects the conformation of the external and transmembrane domains and how they interact with small-molecule inhibitors of HIV-1 entry.
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8
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Contreras X, Mzoughi O, Gaston F, Peterlin MB, Bahraoui E. Protein kinase C-delta regulates HIV-1 replication at an early post-entry step in macrophages. Retrovirology 2012; 9:37. [PMID: 22554282 PMCID: PMC3432598 DOI: 10.1186/1742-4690-9-37] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Accepted: 03/15/2012] [Indexed: 11/17/2022] Open
Abstract
Background Macrophages, which are CD4 and CCR5 positive, can sustain HIV-1 replication for long periods of time. Thus, these cells play critical roles in the transmission, dissemination and persistence of viral infection. Of note, current antiviral therapies do not target macrophages efficiently. Previously, it was demonstrated that interactions between CCR5 and gp120 stimulate PKC. However, the PKC isozymes involved were not identified. Results In this study, we identified PKC-delta as a major cellular cofactor for HIV-1 replication in macrophages. Indeed, PKC-delta was stimulated following the interaction between the virus and its target cell. Moreover, inhibition of PKC-delta blocked the replication of R5-tropic viruses in primary human macrophages. However, this inhibition did not have significant effects on receptor and co-receptor expression or fusion. Additionally, it did not affect the formation of the early reverse transcription product containing R/U5 sequences, but did inhibit the synthesis of subsequent cDNAs. Importantly, the inhibition of PKC-delta altered the redistribution of actin, a cellular cofactor whose requirement for the completion of reverse transcription was previously established. It also prevented the association of the reverse transcription complex with the cytoskeleton. Conclusion This work highlights the importance of PKC-delta during early steps of the replicative cycle of HIV-1 in human macrophages.
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Affiliation(s)
- Xavier Contreras
- Université Paul Sabatier, EA 3038, 118 Route de Narbonne, Toulouse 31062, France.
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9
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Gordón-Alonso M, Rocha-Perugini V, Álvarez S, Moreno-Gonzalo O, Ursa A, López-Martín S, Izquierdo-Useros N, Martínez-Picado J, Muñoz-Fernández MÁ, Yáñez-Mó M, Sánchez-Madrid F. The PDZ-adaptor protein syntenin-1 regulates HIV-1 entry. Mol Biol Cell 2012; 23:2253-63. [PMID: 22535526 PMCID: PMC3374745 DOI: 10.1091/mbc.e11-12-1003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Syntenin-1 is recruited to the human immunodeficiency virus (HIV)-induced capping area but vanishes once the viral particles have entered the cell. Syntenin-1 limits HIV-1 infection. Moreover, syntenin-1 depletion specifically increases the HIV-1 entry step without affecting viral attachment to the cell surface. Silencing of syntenin-1 expression blocks actin polymerization triggered by HIV-1 contact and enhances phosphatidylinositol 4,5-bisphosphate production. Syntenin-1 is a cytosolic adaptor protein involved in several cellular processes requiring polarization. Human immunodeficiency virus type 1 (HIV-1) attachment to target CD4+ T-cells induces polarization of the viral receptor and coreceptor, CD4/CXCR4, and cellular structures toward the virus contact area, and triggers local actin polymerization and phosphatidylinositol 4,5-bisphosphate (PIP2) production, which are needed for successful HIV infection. We show that syntenin-1 is recruited to the plasma membrane during HIV-1 attachment and associates with CD4, the main HIV-1 receptor. Syntenin-1 overexpression inhibits HIV-1 production and HIV-mediated cell fusion, while syntenin depletion specifically increases HIV-1 entry. Down-regulation of syntenin-1 expression reduces F-actin polymerization in response to HIV-1. Moreover, HIV-induced PIP2 accumulation is increased in syntenin-1–depleted cells. Once the virus has entered the target cell, syntenin-1 polarization toward the viral nucleocapsid is lost, suggesting a spatiotemporal regulatory role of syntenin-1 in actin remodeling, PIP2 production, and the dynamics of HIV-1 entry.
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Affiliation(s)
- Mónica Gordón-Alonso
- Servicio de Inmunología, Instituto de Investigación Sanitaria de la Princesa, Hospital Universitario de la Princesa, 28006 Madrid, Spain
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10
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Biard-Piechaczyk M, Borel S, Espert L, de Bettignies G, Coux O. HIV-1, ubiquitin and ubiquitin-like proteins: the dialectic interactions of a virus with a sophisticated network of post-translational modifications. Biol Cell 2012; 104:165-87. [PMID: 22188301 DOI: 10.1111/boc.201100112] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 12/14/2011] [Indexed: 11/26/2022]
Abstract
The modification of intracellular proteins by ubiquitin (Ub) and ubiquitin-like (UbL) proteins is a central mechanism for regulating and fine-tuning all cellular processes. Indeed, these modifications are widely used to control the stability, activity and localisation of many key proteins and, therefore, they are instrumental in regulating cellular functions as diverse as protein degradation, cell signalling, vesicle trafficking and immune response. It is thus no surprise that pathogens in general, and viruses in particular, have developed multiple strategies to either counteract or exploit the complex mechanisms mediated by the Ub and UbL protein conjugation pathways. The aim of this review is to provide an overview on the intricate and conflicting relationships that intimately link HIV-1 and these sophisticated systems of post-translational modifications.
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Affiliation(s)
- Martine Biard-Piechaczyk
- Centre d'étude d'agents Pathogènes et Biotechnologies pour la Santé (CPBS-CNRS), Montpellier Cedex 5, France.
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11
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Kuang YQ, Pang W, Zheng YT, Dupré DJ. NHERF1 regulates gp120-induced internalization and signaling by CCR5, and HIV-1 production. Eur J Immunol 2011; 42:299-310. [PMID: 22028271 DOI: 10.1002/eji.201141801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 09/15/2011] [Accepted: 10/21/2011] [Indexed: 11/10/2022]
Abstract
The scaffolding protein Na(+) /H(+) exchanger regulator factor 1 (NHERF1) plays an important role in the trafficking of G protein-coupled receptors. We previously demonstrated that NHERF1 is involved in chemokine receptor CCR5 homodimer internalization and signal transduction. Given the importance of CCR5 internalization during HIV-1 infection, we evaluated NHERF1's contribution in HIV-1 infection. We challenged human osteosarcoma cells coexpressing CD4 and CCR5 cells expressing either NHERF1 fragment domains or WT NHERF1 with an HIV-1 strain to examine the effects of NHERF1 on HIV-1 entry and replication. WT NHERF1 potentiates HIV-1 envelope gp120-induced CCR5 internalization, and promotes the replication of HIV-1. In order to better understand how NHERF1 affects signal transduction, different domains of NHERF1 were overexpressed in cells to analyze their effect on the different signaling pathways. Here, we show that NHERF1 can associate with CCR5, and promote activation of the gp120-induced MAPK/ERK, focal adhesion kinase and RhoA (Ras homolog gene family member A) signaling pathways. NHERF1 overexpression also increases HIV-1 host cell migration triggered by gp120 via focal adhesion kinase (FAK) signaling. Finally, NHERF1 enhanced actin filament rearrangement in host cells, an important step in post-entry HIV-1 replication events. While postsynaptic density 95/disk-large/zonula occludens 2 (PDZ2) appears to be the major contributor in those events, other domains also participate in the regulation of gp120-induced signaling pathways. Altogether, our results suggest a very important role of the scaffold NHERF1 in the regulation of HIV-1 entry and replication.
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Affiliation(s)
- Yi-Qun Kuang
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
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12
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Giroud C, Chazal N, Briant L. Cellular kinases incorporated into HIV-1 particles: passive or active passengers? Retrovirology 2011; 8:71. [PMID: 21888651 PMCID: PMC3182982 DOI: 10.1186/1742-4690-8-71] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 09/02/2011] [Indexed: 11/10/2022] Open
Abstract
Phosphorylation is one of the major mechanisms by which the activities of protein factors can be regulated. Such regulation impacts multiple key-functions of mammalian cells, including signal transduction, nucleo-cytoplasmic shuttling, macromolecular complexes assembly, DNA binding and regulation of enzymatic activities to name a few. To ensure their capacities to replicate and propagate efficiently in their hosts, viruses may rely on the phosphorylation of viral proteins to assist diverse steps of their life cycle. It has been known for several decades that particles from diverse virus families contain some protein kinase activity. While large DNA viruses generally encode for viral kinases, RNA viruses and more precisely retroviruses have acquired the capacity to hijack the signaling machinery of the host cell and to embark cellular kinases when budding. Such property was demonstrated for HIV-1 more than a decade ago. This review summarizes the knowledge acquired in the field of HIV-1-associated kinases and discusses their possible function in the retroviral life cycle.
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Affiliation(s)
- Charline Giroud
- Centre d'Études d'Agents Pathogènes et Biotechnologies pour la Santé, UMR5236 CNRS - Université Montpellier 1-Montpellier 2, Montpellier, France
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13
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Furler RL, Uittenbogaart CH. Signaling through the P38 and ERK pathways: a common link between HIV replication and the immune response. Immunol Res 2011; 48:99-109. [PMID: 20725863 DOI: 10.1007/s12026-010-8170-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
One of the defining characteristics of HIV is its ability to manipulate the human immune response to promote its own replication. Since the beginning of the epidemic, there has been controversy whether a robust immune response to the virus is beneficial or detrimental for the host. Therefore, the effects of HIV on signaling pathways and cytokine production need to be characterized in order to distinguish between protective immune responses and inappropriate immune activation. Cytokine and biomarker expression during HIV infection results from the combined effects of intracellular signaling pathways orchestrated by kinases like P38 and ERK. The P38 and ERK Mitogen-Activated Protein Kinase (MAPK) pathways govern the regulation of cytokines (IL-2, IL-10, and TNF-α) as well biomarkers (PD-1, Fas/FasL, among others) that are skewed in chronic HIV infection. HIV utilizes the P38 and ERK pathways to produce new virions and to deplete CD4+ T cells from the host's immune system. Understanding the interplay between HIV and the cytokines induced by activation of the P38 and ERK pathways may provide insights into HIV immunopathogenesis and the development of a protective vaccine.
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Affiliation(s)
- Robert L Furler
- Department of Microbiology, Immunology & Molecular Genetics, UCLA AIDS Institute, David E. Geffen School of Medicine, University of California-Los Angeles, CA 90095-7363, USA
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14
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Li Z, Sheng T, Wan X, Liu T, Wu H, Dong J. Expression of HERV-K correlates with status of MEK-ERK and p16INK4A-CDK4 pathways in melanoma cells. Cancer Invest 2010; 28:1031-7. [PMID: 20874005 DOI: 10.3109/07357907.2010.512604] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The dysregulated ERK and RB pathways often coexist in melanoma cells. The K-type human endogenous retrovirus (HERV-K) is implicated in melanomagenesis. Some of the phenotypes that are modified by HERV-K (e.g., changes in cell shape, melanin production, and anchorage-dependent growth) overlap with those that are regulated by ERK and RB pathways. As ERK signaling can regulate retroviruses, we hypothesized that HERV-K expression is controlled by ERK-RB pathways. We found that the levels of HERV-K GAG and EVE correlated with the activation of ERK and loss of p16INK4A and that inhibition of MEK or CDK4, especially in combination, reduced HERV-K EVE in melanoma cells.
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Affiliation(s)
- Zhongwu Li
- Sealy Center for Cancer Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555-0743, USA
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Vitiello M, Finamore E, Falanga A, Raieta K, Cantisani M, Galdiero F, Pedone C, Galdiero M, Galdiero S. Viral fusion peptides induce several signal transduction pathway activations that are essential for interleukin-10 and beta-interferon production. Intervirology 2010; 53:381-9. [PMID: 20606459 PMCID: PMC7179556 DOI: 10.1159/000317287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 12/22/2009] [Indexed: 01/22/2023] Open
Abstract
Objectives The deciphering of intracellular signaling pathways that are activated by the interaction between viral fusion peptides and cellular membranes are important for the understanding of both viral replication strategies and host defense mechanisms. Methods Fusion peptides of several enveloped viruses belonging to different virus families were prepared by standard 9-fluorenylmethoxycarbonyl polyamine solid-phase synthesis and used to stimulate U937 cells in vitro to analyze the phosphorylation patterns of the signaling pathways (PKC, Src, Akt, and MAPK pathways). Immunoprecipitation and Western blotting were carried out by using phosphospecific antibodies. All samples were also assayed for the presence of IL-10 and IFN-β by ELISA and activation of nuclear factors (AP-1 and NF-κB). Results We have demonstrated that hydrophobic domains of fusion proteins are able to induce several transduction pathways that lead to cytokine (IFN-β and IL-10) production, an event that appears to be dependent on early activation of AP-1 and NF-κB. Conclusions The results obtained on the signaling activity of fusion peptides from different viruses enabled us to shed some light on the complex mechanism of viral entry and more precisely we focused on the exact signaling event induced by hydrophobic domains characteristic of fusion peptides interacting with the cell membrane.
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Affiliation(s)
- Mariateresa Vitiello
- Department of Experimental Medicine, Section of Microbiology and Clinical Microbiology, Second University of Naples, Naples, Italy
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