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Stephens C, Naghavi MH. The host cytoskeleton: a key regulator of early HIV-1 infection. FEBS J 2024; 291:1835-1848. [PMID: 36527282 PMCID: PMC10272291 DOI: 10.1111/febs.16706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/29/2022] [Accepted: 12/16/2022] [Indexed: 12/23/2022]
Abstract
Due to its central role in cell biology, the cytoskeleton is a key regulator of viral infection, influencing nearly every step of the viral life cycle. In this review, we will discuss the role of two key components of the cytoskeleton, namely the actin and microtubule networks in early HIV-1 infection. We will discuss key contributions to processes ranging from the attachment and entry of viral particles at the cell surface to their arrival and import into the nucleus and identify areas where further research into this complex relationship may yield new insights into HIV-1 pathogenesis.
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Affiliation(s)
- Christopher Stephens
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Mojgan H. Naghavi
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
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2
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Wang W, Truong K, Ye C, Sharma S, He H, Liu L, Wen M, Misra A, Zhou P, Kimata JT. Engineered CD4 T cells expressing a membrane anchored viral inhibitor restrict HIV-1 through cis and trans mechanisms. Front Immunol 2023; 14:1167965. [PMID: 37781368 PMCID: PMC10538569 DOI: 10.3389/fimmu.2023.1167965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 08/31/2023] [Indexed: 10/03/2023] Open
Abstract
HIV-1 infection of target cells can occur through either cell-free virions or cell-cell transmission in a virological synapse, with the latter mechanism of infection reported to be 100- to 1,000-fold more efficient. Neutralizing antibodies and entry inhibitors effectively block cell-free HIV-1, but with few exceptions, they display much less inhibitory activity against cell-mediated HIV-1 transmission. Previously, we showed that engineering HIV-1 target cells by genetically linking single-chain variable fragments (scFvs) of antibodies to glycosyl phosphatidylinositol (GPI) potently blocks infection by cell-free virions and cell-mediated infection by immature dendritic cell (iDC)-captured HIV-1. Expression of scFvs on CD4+ cell lines by transduction with X5 derived anti-HIV-1 Env antibody linked to a GPI attachment signal directs GPI-anchored scFvs into lipid rafts of the plasma membrane. In this study, we further characterize the effect of GPI-scFv X5 on cell-cell HIV-1 transmission from DCs to target cells. We report that expression of GPI-scFv X5 in transduced CD4+ cell lines and human primary CD4+ T cells potently restricts viral replication in iDC- or mDC-captured HIV-1 in trans. Using live-cell imaging, we observed that when GPI-GFP or GPI-scFv X5 transduced T cells are co-cultured with iDCs, GPI-anchored proteins enrich in contact zones and subsequently migrate from T cells into DCs, suggesting that transferred GPI-scFv X5 interferes with HIV-1 infection of iDCs. We conclude that GPI-scFv X5 on the surface of transduced CD4+ T cells not only potently blocks cell-mediated infection by DCs, but it transfers from transduced cells to the surface of iDCs and neutralizes HIV-1 replication in iDCs. Our findings have important implications for HIV-1 antibody-based immunotherapies as they demonstrate a viral inhibitory effect that extends beyond the transduced CD4+ T cells to iDCs which can enhance HIV-1 replication.
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Affiliation(s)
- Weiming Wang
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Khanghy Truong
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Chaobaihui Ye
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Suman Sharma
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Huan He
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Lihong Liu
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Michael Wen
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Anisha Misra
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Paul Zhou
- Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Jason T. Kimata
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
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Iida N, Kawahara M, Hirota R, Shibagaki Y, Hattori S, Morikawa Y. A Proteomic Analysis of Detergent-Resistant Membranes in HIV Virological Synapse: The Involvement of Vimentin in CD4 Polarization. Viruses 2023; 15:1266. [PMID: 37376566 DOI: 10.3390/v15061266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
The cell-cell contact between HIV-1-infected and uninfected cells forms a virological synapse (VS) to allow for efficient HIV-1 transmission. Not only are HIV-1 components polarized and accumulate at cell-cell interfaces, but viral receptors and lipid raft markers are also. To better understand the nature of the HIV-1 VS, detergent-resistant membrane (DRM) fractions were isolated from an infected-uninfected cell coculture and compared to those from non-coculture samples using 2D fluorescence difference gel electrophoresis. Mass spectrometry revealed that ATP-related enzymes (ATP synthase subunit and vacuolar-type proton ATPase), protein translation factors (eukaryotic initiation factor 4A and mitochondrial elongation factor Tu), protein quality-control-related factors (protein disulfide isomerase A3 and 26S protease regulatory subunit), charged multivesicular body protein 4B, and vimentin were recruited to the VS. Membrane flotation centrifugation of the DRM fractions and confocal microscopy confirmed these findings. We further explored how vimentin contributes to the HIV-1 VS and found that vimentin supports HIV-1 transmission through the recruitment of CD4 to the cell-cell interface. Since many of the molecules identified in this study have previously been suggested to be involved in HIV-1 infection, we suggest that a 2D difference gel analysis of DRM-associated proteins may reveal the molecules that play crucial roles in HIV-1 cell-cell transmission.
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Affiliation(s)
- Naoyuki Iida
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Madoka Kawahara
- Omura Satoshi Memorial Institute and Graduate School for Infection Control, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Riku Hirota
- Omura Satoshi Memorial Institute and Graduate School for Infection Control, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Yoshio Shibagaki
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Seisuke Hattori
- School of Pharmacy, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
| | - Yuko Morikawa
- Omura Satoshi Memorial Institute and Graduate School for Infection Control, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
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Discovery of Bis-Imidazoline Derivatives as New CXCR4 Ligands. Molecules 2023; 28:molecules28031156. [PMID: 36770826 PMCID: PMC9920567 DOI: 10.3390/molecules28031156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
The chemokine receptor CXCR4 and its ligand CXCL12 regulate leukocyte trafficking, homeostasis and functions and are potential therapeutic targets in many diseases such as HIV-1 infection and cancers. Here, we identified new CXCR4 ligands in the CERMN chemical library using a FRET-based high-throughput screening assay. These are bis-imidazoline compounds comprising two imidazole rings linked by an alkyl chain. The molecules displace CXCL12 binding with submicromolar potencies, similarly to AMD3100, the only marketed CXCR4 ligand. They also inhibit anti-CXCR4 mAb 12G5 binding, CXCL12-mediated chemotaxis and HIV-1 infection. Further studies with newly synthesized derivatives pointed out to a role of alkyl chain length on the bis-imidazoline properties, with molecules with an even number of carbons equal to 8, 10 or 12 being the most potent. Interestingly, these differ in the functions of CXCR4 that they influence. Site-directed mutagenesis and molecular docking predict that the alkyl chain folds in such a way that the two imidazole groups become lodged in the transmembrane binding cavity of CXCR4. Results also suggest that the alkyl chain length influences how the imidazole rings positions in the cavity. These results may provide a basis for the design of new CXCR4 antagonists targeting specific functions of the receptor.
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5
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Ripa I, Andreu S, López-Guerrero JA, Bello-Morales R. Membrane Rafts: Portals for Viral Entry. Front Microbiol 2021; 12:631274. [PMID: 33613502 PMCID: PMC7890030 DOI: 10.3389/fmicb.2021.631274] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 01/14/2021] [Indexed: 02/02/2023] Open
Abstract
Membrane rafts are dynamic, small (10-200 nm) domains enriched with cholesterol and sphingolipids that compartmentalize cellular processes. Rafts participate in roles essential to the lifecycle of different viral families including virus entry, assembly and/or budding events. Rafts seem to participate in virus attachment and recruitment to the cell surface, as well as the endocytic and non-endocytic mechanisms some viruses use to enter host cells. In this review, we will introduce the specific role of rafts in viral entry and define cellular factors implied in the choice of one entry pathway over the others. Finally, we will summarize the most relevant information about raft participation in the entry process of enveloped and non-enveloped viruses.
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Affiliation(s)
- Inés Ripa
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Sabina Andreu
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - José Antonio López-Guerrero
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Raquel Bello-Morales
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
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6
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Fellows T, Ho L, Flanagan S, Fogel R, Ojo D, Limson J. Gold nanoparticle-streptavidin conjugates for rapid and efficient screening of aptamer function in lateral flow sensors using novel CD4-binding aptamers identified through Crossover-SELEX. Analyst 2020; 145:5180-5193. [PMID: 32567629 DOI: 10.1039/d0an00634c] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
To decrease the burden of laborious and reagent-intensive screening of modified aptamers, their binding function requires assessment in assay formats compatible with the end diagnostic application. Here, we report on the use of an alternative and cost-effective approach: a rapid lateral flow assay (LFA) utilising streptavidin-conjugated gold nanoparticles (AuNP) as reporter molecules to screen novel ssDNA aptamers for their ability to detect CD4. Crossover-SELEX was employed to identify CD4-targeting aptamers from a ssDNA library enriched against a recombinant human CD4 protein (hCD4) conjugated to magnetic-beads and to endogenous CD4 expressed by U937 cells. Counter-selection with IgG-conjugated beads and CD4-negative Ramos RA-1 cells was employed. Following SELEX, four sequences (U4, U14, U20 and U26) were selected for candidate screening. Fluorescence confocal microscopy showed comparable localization of the Cy5-labeled aptamer U26, compared to antibodies binding CD4's cytoplasmic domain. Aptamer-hCD4 binding kinetics were evaluated by a qPCR-based magnetic-bead binding assay to unmodified aptamers. U26 exhibited the highest binding affinity (Kd = 2.93 ± 1.03 nM) to hCD4-conjugated beads. Citrate-stabilized gold nanoparticles (mean particle diameter, 10.59 ± 1.81 nm) were functionalized with streptavidin to allow immobilization of biotin-labeled aptamers. Except for U4, the aptamer-gold nanoparticle conjugates (Apt-AuNP) remained stable under physiological conditions with their size (approx. 15 nm) appropriate for use in the LFAs. Lateral-flow based screening was used to evaluate the suitability of the Apt-AuNPs as CD4-detecting reporter molecules by immobilizing hCD4 and flowing the nanoparticle conjugates across the LFA. Using this approach, two novel sequences were identified as being suitable for the detection of hCD4: visual detection at 9 min was obtained using U20 or U26. After 20 min, equivalent colorimetric hCD4 responses were observed between anti-CD4 monoclonal antibody (ΔI = 94.19 ± 3.71), an existing CD4 aptamer F1-62 (ΔI = 90.31 ± 19.31) and U26 (ΔI = 100.14 ± 14.61) LFA's, each demonstrating high specificity to hCD4 compared to IgG. From the above, Crossover-SELEX allowed for the successful identification of ssDNA aptamers able to detect hCD4. Streptavidin-conjugated AuNPs, when bound to candidate aptamers, show potential application here as screening tools for the rapid evaluation of aptamer performance in low-cost lateral flow diagnostics.
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Affiliation(s)
- Tamika Fellows
- Rhodes University Biotechnology Innovation Centre, Grahamstown, Eastern Cape, South Africa.
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7
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Membrane Dynamics in Health and Disease: Impact on Cellular Signalling. J Membr Biol 2019; 252:213-226. [PMID: 31435696 DOI: 10.1007/s00232-019-00087-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 08/07/2019] [Indexed: 12/16/2022]
Abstract
Biological membranes display a staggering complexity of lipids and proteins orchestrating cellular functions. Superior analytical tools coupled with numerous functional cellular screens have enabled us to query their role in cellular signalling, trafficking, guiding protein structure and function-all of which rely on the dynamic membrane lipid properties indispensable for proper cellular functions. Alteration of these has led to emergence of various pathological conditions, thus opening an area of lipid-centric therapeutic approaches. This perspective is a short summary of the dynamic properties of membranes essential for proper cellular functions, dictating both protein and lipid functions, and mis-regulated in diseases. Towards the end, we focus on some challenges lying ahead and potential means to tackle the same, mainly underscored by multi-disciplinary approaches.
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8
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CCR5 Revisited: How Mechanisms of HIV Entry Govern AIDS Pathogenesis. J Mol Biol 2018; 430:2557-2589. [PMID: 29932942 DOI: 10.1016/j.jmb.2018.06.027] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/10/2018] [Accepted: 06/13/2018] [Indexed: 01/01/2023]
Abstract
The chemokine receptor CCR5 has been the focus of intensive studies since its role as a coreceptor for HIV entry was discovered in 1996. These studies lead to the development of small molecular drugs targeting CCR5, with maraviroc becoming in 2007 the first clinically approved chemokine receptor inhibitor. More recently, the apparent HIV cure in a patient transplanted with hematopoietic stem cells devoid of functional CCR5 rekindled the interest for inactivating CCR5 through gene therapy and pharmacological approaches. Fundamental research on CCR5 has also been boosted by key advances in the field of G-protein coupled receptor research, with the realization that CCR5 adopts a variety of conformations, and that only a subset of these conformations may be targeted by chemokine ligands. In addition, recent genetic and pathogenesis studies have emphasized the central role of CCR5 expression levels in determining the risk of HIV and SIV acquisition and disease progression. In this article, we propose to review the key properties of CCR5 that account for its central role in HIV pathogenesis, with a focus on mechanisms that regulate CCR5 expression, conformation, and interaction with HIV envelope glycoproteins.
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Filippini A, Sica G, D'Alessio A. The caveolar membrane system in endothelium: From cell signaling to vascular pathology. J Cell Biochem 2018; 119:5060-5071. [PMID: 29637636 DOI: 10.1002/jcb.26793] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 02/16/2018] [Indexed: 12/12/2022]
Abstract
Caveolae are 50- to 100-nm cholesterol and glycosphingolipid-rich flask-shaped invaginations commonly observed in many terminally differentiated cells. These organelles have been described in many cell types and are particularly abundant in endothelial cells, where they have been involved in the regulation of certain signaling pathways. Specific scaffolding proteins termed caveolins, along with the more recently discovered members of the cavin family, represent the major protein components during caveolae biogenesis. In addition, multiple studies aimed to investigate the expression and the regulation of these proteins significantly contributed to elucidate the role of caveolae and caveolins in endothelial cell physiology and disease. The aim of this review is to survey recent evidence of the involvement of the caveolar network in endothelial cell biology and endothelial cell dysfunction.
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Affiliation(s)
- Antonio Filippini
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Unit of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - Gigliola Sica
- Istituto di Istologia ed Embriologia, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Alessio D'Alessio
- Istituto di Istologia ed Embriologia, Università Cattolica del Sacro Cuore, Rome, Italy
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Samuels S, Alwan Z, Egnin M, Jaynes J, Connell TD, Bernard GC, Nashar T. Novel Therapeutic Approach for Inhibition of HIV-1 Using Cell-Penetrating Peptide and Bacterial Toxins. ACTA ACUST UNITED AC 2017; 8. [PMID: 29226013 PMCID: PMC5719890 DOI: 10.4172/2155-6113.1000737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Despite advancements in our understanding of HIV-1 pathogenesis, critical virus components for immunity, vaccines trials, and drugs development, challenges remain in the fight against HIV-1. Of great importance is the inhibitory function of microbicidal cell penetrating peptides and bacterial toxins that interfere with production and neutralize infection of HIV-1 particles. We demonstrate that the neutralizing activity of a cationic 18 amino acids peptide, is similar to a broadly neutralizing human antibody, and inhibits production of two HIV-1 strains in human cell lines. Pretreatment of cells with bacterial toxins or toxoids derived from enterotoxigenic E. coli, boost subsequent activity of the peptide against HIV-1, to inhibit simultaneously production and infection. The synthetic peptide crosses the cell membrane into the cytoplasm and nucleus. In vitro analysis of a possible target for this peptide revealed specific binding to recombinant HIV-1 gag p24. This is the first demonstration of a synergy between bacterial toxins and a cell-penetrating peptide against HIV-1.
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Affiliation(s)
- Steven Samuels
- Environment and Nutrition Sciences, Faculty of Agriculture, Tuskegee University, Tuskegee, Alabama, USA.,Department of Life and Earth Sciences, Perimeter College at Georgia State University, 555 North Indian Creek Drive, Clarkston, USA
| | - Zainab Alwan
- Department of Pathobiology, College of Veterinary Medicine, Tuskegee University, Tuskegee, Alabama, USA.,Department of Community Health, Institute of Medical Technology, Middle Technical University Baghdad, Iraq
| | - Marceline Egnin
- Environment and Nutrition Sciences, Faculty of Agriculture, Tuskegee University, Tuskegee, Alabama, USA
| | - Jessie Jaynes
- Environment and Nutrition Sciences, Faculty of Agriculture, Tuskegee University, Tuskegee, Alabama, USA
| | - Terry D Connell
- Department of Microbiology and Immunology, The Witebsky Center for Microbial Pathogenesis and Immunology, Buffalo, New York, USA
| | - Gregory C Bernard
- Environment and Nutrition Sciences, Faculty of Agriculture, Tuskegee University, Tuskegee, Alabama, USA
| | - Toufic Nashar
- Department of Pathobiology, College of Veterinary Medicine, Tuskegee University, Tuskegee, Alabama, USA
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Bechtel TJ, Weerapana E. From structure to redox: The diverse functional roles of disulfides and implications in disease. Proteomics 2017; 17. [PMID: 28044432 DOI: 10.1002/pmic.201600391] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/02/2016] [Accepted: 12/28/2016] [Indexed: 12/16/2022]
Abstract
This review provides a comprehensive overview of the functional roles of disulfide bonds and their relevance to human disease. The critical roles of disulfide bonds in protein structure stabilization and redox regulation of protein activity are addressed. Disulfide bonds are essential to the structural stability of many proteins within the secretory pathway and can exist as intramolecular or inter-domain disulfides. The proper formation of these bonds often relies on folding chaperones and oxidases such as members of the protein disulfide isomerase (PDI) family. Many of the PDI family members catalyze disulfide-bond formation, reduction, and isomerization through redox-active disulfides and perturbed PDI activity is characteristic of carcinomas and neurodegenerative diseases. In addition to catalytic function in oxidoreductases, redox-active disulfides are also found on a diverse array of cellular proteins and act to regulate protein activity and localization in response to oxidative changes in the local environment. These redox-active disulfides are either dynamic intramolecular protein disulfides or mixed disulfides with small-molecule thiols generating glutathionylation and cysteinylation adducts. The oxidation and reduction of redox-active disulfides are mediated by cellular reactive oxygen species and activity of reductases, such as glutaredoxin and thioredoxin. Dysregulation of cellular redox conditions and resulting changes in mixed disulfide formation are directly linked to diseases such as cardiovascular disease and Parkinson's disease.
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Affiliation(s)
- Tyler J Bechtel
- Department of Chemistry, Boston College, Chestnut Hill, MA, USA
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12
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Dumas F, Haanappel E. Lipids in infectious diseases - The case of AIDS and tuberculosis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1636-1647. [PMID: 28535936 DOI: 10.1016/j.bbamem.2017.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 05/11/2017] [Accepted: 05/14/2017] [Indexed: 02/07/2023]
Abstract
Lipids play a central role in many infectious diseases. AIDS (Acquired Immune Deficiency Syndrome) and tuberculosis are two of the deadliest infectious diseases to have struck mankind. The pathogens responsible for these diseases, Human Immunodeficiency Virus-1 and Mycobacterium tuberculosis, rely on lipids and on lipid membrane properties to gain access to their host cells, to persist in them and ultimately to egress from their hosts. In this Review, we discuss the life cycles of these pathogens and the roles played by lipids and membranes. We then give an overview of therapies that target lipid metabolism, modulate host membrane properties or implement lipid-based drug delivery systems. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
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Affiliation(s)
- Fabrice Dumas
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, France.
| | - Evert Haanappel
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, France
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13
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Moolla N, Killick M, Papathanasopoulos M, Capovilla A. Thioredoxin (Trx1) regulates CD4 membrane domain localization and is required for efficient CD4-dependent HIV-1 entry. Biochim Biophys Acta Gen Subj 2016; 1860:1854-63. [PMID: 27233453 DOI: 10.1016/j.bbagen.2016.05.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 05/12/2016] [Accepted: 05/21/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUND CD4 is a glycoprotein expressed on the surfaces of certain immune cells. On lymphocytes, an important function of CD4 is to co-engage Major Histocompatibility Complex (MHC) molecules with the T Cell Receptor (TCR), a process that is essential for antigen-specific activation of T cells. CD4 localizes dynamically into distinct membrane microdomains, an important feature of its immunoregulatory function that has also been shown to influence the efficiency of HIV replication. However, the mechanism by which CD4 localization is regulated and the biological significance of this is incompletely understood. METHODS In this study, we used confocal microscopy, density-gradient centrifugation and flow cytometry to analyze dynamic redox-dependent effects on CD4 membrane domain localization. RESULTS Blocking cell surface redox exchanges with both a membrane-impermeable sulfhydryl blocker (DTNB) and specific antibody inhibitors of Thioredoxin-1 (Trx1) induces translocation of CD4 into detergent-resistant membrane domains (DRM). In contrast, Trx1 inactivation does not change the localization of the chemokine receptor CCR5, suggesting that this effect is targeted. Moreover, DTNB treatment and Trx1 depletion coincide with strong inhibition of CD4-dependent HIV entry, but only moderate reductions in the infectivity of a CD4-independent HIV pseudovirion. CONCLUSIONS Changes in the extracellular redox environment, potentially mediated by allosteric consequences of functional disulfide bond oxidoreduction, may represent a signal for translocation of CD4 into DRM clusters, and this sequestration, another potential mechanism by which the anti-HIV effects of cell surface oxidoreductase inhibition are exerted. GENERAL SIGNIFICANCE Extracellular redox conditions may regulate CD4 function by potentiating changes in its membrane domain localization.
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Affiliation(s)
- Naazneen Moolla
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, University of the Witwatersrand, Faculty of Health Sciences, 7 York Road Parktown, 2193 Johannesburg, South Africa
| | - Mark Killick
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, University of the Witwatersrand, Faculty of Health Sciences, 7 York Road Parktown, 2193 Johannesburg, South Africa
| | - Maria Papathanasopoulos
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, University of the Witwatersrand, Faculty of Health Sciences, 7 York Road Parktown, 2193 Johannesburg, South Africa
| | - Alexio Capovilla
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, University of the Witwatersrand, Faculty of Health Sciences, 7 York Road Parktown, 2193 Johannesburg, South Africa.
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14
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Dumas F, Preira P, Salomé L. Membrane organization of virus and target cell plays a role in HIV entry. Biochimie 2014; 107 Pt A:22-7. [PMID: 25193376 PMCID: PMC7126522 DOI: 10.1016/j.biochi.2014.08.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/22/2014] [Indexed: 01/08/2023]
Abstract
The initial steps of the Human Immunodeficiency Virus (HIV) replication cycle play a crucial role that arbitrates viral tropism and infection efficiency. Before the release of its genome into the host cell cytoplasm, viruses operate a complex sequence of events that take place at the plasma membrane of the target cell. The first step is the binding of the HIV protein envelope (Env) to the cellular receptor CD4. This triggers conformational changes of the gp120 viral protein that allow its interaction with a co-receptor that can be either CCR5 or CXCR4, defining the tropism of the virus entering the cell. This sequential interaction finally drives the fusion of the viral and host cell membrane or to the endocytosis of the viruses. Here, we discuss how the membrane composition and organization of both the virus and the target cell can affect these steps and thus influence the capability of the viruses to infect cells. An overview of lipid role in HIV infection is proposed. We discuss the influence of lipid composition on HIV early steps of infection. We discuss the role of membrane organization an dynamics in HIV entry.
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Affiliation(s)
- Fabrice Dumas
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, F-31077 Toulouse, France; Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France.
| | - Pascal Preira
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, F-31077 Toulouse, France
| | - Laurence Salomé
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 route de Narbonne, F-31077 Toulouse, France.
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The productive entry pathway of HIV-1 in macrophages is dependent on endocytosis through lipid rafts containing CD4. PLoS One 2014; 9:e86071. [PMID: 24465876 PMCID: PMC3899108 DOI: 10.1371/journal.pone.0086071] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 12/05/2013] [Indexed: 12/20/2022] Open
Abstract
Macrophages constitute an important reservoir of HIV-1 infection, yet HIV-1 entry into these cells is poorly understood due to the difficulty in genetically manipulating primary macrophages. We developed an effective genetic approach to manipulate the sub-cellular distribution of CD4 in macrophages, and investigated how this affects the HIV-1 entry pathway. Pluripotent Stem Cells (PSC) were transduced with lentiviral vectors designed to manipulate CD4 location and were then differentiated into genetically modified macrophages. HIV-1 infection of these cells was assessed by performing assays that measure critical steps of the HIV-1 lifecycle (fusion, reverse transcription, and expression from HIV-1 integrants). Expression of LCK (which tethers CD4 to the surface of T cells, but is not normally expressed in macrophages) in PSC-macrophages effectively tethered CD4 at the cell surface, reducing its normal endocytic recycling route, and increasing surface CD4 expression 3-fold. This led to a significant increase in HIV-1 fusion and reverse transcription, but productive HIV-1 infection efficiency (as determined by reporter expression from DNA integrants) was unaffected. This implies that surface-tethering of CD4 sequesters HIV-1 into a pathway that is unproductive in macrophages. Secondly, to investigate the importance of lipid rafts (as detergent resistant membranes - DRM) in HIV-1 infection, we generated genetically modified PSC-macrophages that express CD4 mutants known to be excluded from DRM. These macrophages were significantly less able to support HIV-1 fusion, reverse-transcription and integration than engineered controls. Overall, these results support a model in which productive infection by HIV-1 in macrophages occurs via a CD4-raft-dependent endocytic uptake pathway.
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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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17
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Kamiyama H, Kakoki K, Shigematsu S, Izumida M, Yashima Y, Tanaka Y, Hayashi H, Matsuyama T, Sato H, Yamamoto N, Sano T, Shidoji Y, Kubo Y. CXCR4-tropic, but not CCR5-tropic, human immunodeficiency virus infection is inhibited by the lipid raft-associated factors, acyclic retinoid analogs, and cholera toxin B subunit. AIDS Res Hum Retroviruses 2013; 29:279-88. [PMID: 22845664 DOI: 10.1089/aid.2012.0174] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Development of an effective low-cost anti-acquired immunodeficiency syndrome (AIDS) drugs is needed for treatment of AIDS patients in developing countries. Host cell lipid raft microdomains, which are enriched with cholesterol, glycolipids, ceramide, and gangliosides, are important for human immunodeficiency virus type 1 (HIV-1) entry. Retinoid analogs have been shown to modulate ceramide levels in the cell membrane, while cholera toxin B subunit (CT-B) specifically binds to the ganglioside GM1. In this study, we found that the acyclic retinoid analogs geranylgeranoic acid (GGA) and NIK-333 as well as CT-B efficiently attenuate CXCR4-tropic, but not CCR5-tropic, HIV-1 vector infection. We also found that GGA and NIK-333 suppress CXCR4-tropic HIV-1 infection by attenuating CXCR4 expression. CT-B also attenuated CXCR4-tropic HIV-1 infection, but did not suppress CXCR4 expression. These results suggest a distinct role for lipid raft microdomains in CXCR4- and CCR5-tropic HIV-1 infections and illuminate novel agents for the development of AIDS therapy.
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Affiliation(s)
- Haruka Kamiyama
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
- Department of Molecular and Cellular Biology, Graduate School of Human Health Sciences, University of Nagasaki, Nagasaki, Japan
| | - Katsura Kakoki
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
| | - Sayuri Shigematsu
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Mai Izumida
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Yuka Yashima
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Yuetsu Tanaka
- Department of Immunology, Graduate School and Faculty of Medicine, University of the Ryukyu, Okinawa, Japan
| | - Hideki Hayashi
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Toshifumi Matsuyama
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Hironori Sato
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
| | - Naoki Yamamoto
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
- Department of Microbiology, National University of Singapore, Singapore, Singapore
| | | | - Yoshihiro Shidoji
- Department of Molecular and Cellular Biology, Graduate School of Human Health Sciences, University of Nagasaki, Nagasaki, Japan
| | - Yoshinao Kubo
- Division of Cytokine Signaling, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- Department of AIDS Research, Institute of Tropical Medicine, G-COE, Nagasaki University, Nagasaki, Japan
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Zhukovsky MA, Lee PH, Ott A, Helms V. Putative cholesterol-binding sites in human immunodeficiency virus (HIV) coreceptors CXCR4 and CCR5. Proteins 2012; 81:555-67. [DOI: 10.1002/prot.24211] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 08/31/2012] [Accepted: 10/11/2012] [Indexed: 11/08/2022]
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Choi YJ, Jung J, Chung HK, Im E, Rhee SH. PTEN regulates TLR5-induced intestinal inflammation by controlling Mal/TIRAP recruitment. FASEB J 2012; 27:243-54. [PMID: 23038756 DOI: 10.1096/fj.12-217596] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Defective IL-10 allele is a risk factor for intestinal inflammation. Indeed, IL-10(-/-) mice are predisposed to spontaneous colitis in the presence of intestinal microbiota, indicating that microbial factors contribute to developing intestinal inflammation. By recognizing flagellin, TLR5 plays a quintessential role in microbial recognition in intestinal epithelial cells. Here, we treated flagellin (1.0 μg/mouse/d) in mouse colon and found that it elicited colonic inflammation in IL-10(-/-) mice, characterized with tissue hypertrophy, inflamed epithelium, and enhanced cytokine production in the colon (MPO, KC, IL-6; ≥2-fold; P < 0.05). These inflammatory effects were dramatically inhibited in TLR5(-/-);IL-10(-/-) mice. Intestinal epithelium specific PTEN deletion significantly attenuated flagellin-promoted colonic inflammation in IL-10(-/-) mice. As a molecular mechanism that PTEN deletion inhibited TLR5-elicited responses, we hypothesized that PTEN regulated TLR5-induced responses by controlling the involvement of Mal in TLR5 engagement. Mal interacted with TLR5 on flagellin, and Mal deficiency inhibited flagellin-induced responses in intestinal epithelial cells. Similarly, Mal(-/-);IL-10(-/-) mice showed reduced flagellin-promoted responses. Furthermore, PTEN deletion disrupted Mal-TLR5 interaction, resulting in diminished TLR5-induced responses. PTEN deletion impeded Mal localization at the plasma membrane and suppressed Mal-TLR5 interaction. These results suggest that, by controlling Mal recruitment, PTEN regulates TLR5-induced inflammatory responses.
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Affiliation(s)
- Yoon Jeong Choi
- Division of Digestive Diseases, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, California 90095, USA
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Spear M, Guo J, Wu Y. The trinity of the cortical actin in the initiation of HIV-1 infection. Retrovirology 2012; 9:45. [PMID: 22640593 PMCID: PMC3416652 DOI: 10.1186/1742-4690-9-45] [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: 03/02/2012] [Accepted: 05/03/2012] [Indexed: 12/16/2022] Open
Abstract
For an infecting viral pathogen, the actin cortex inside the host cell is the first line of intracellular components that it encounters. Viruses devise various strategies to actively engage or circumvent the actin structure. In this regard, the human immunodeficiency virus-1 (HIV-1) exemplifies command of cellular processes to take control of actin dynamics for the initiation of infection. It has becomes increasingly evident that cortical actin presents itself both as a barrier to viral intracellular migration and as a necessary cofactor that the virus must actively engage, particularly, in the infection of resting CD4 blood T cells, the primary targets of HIV-1. The coercion of this most fundamental cellular component permits infection by facilitating entry, reverse transcription, and nuclear migration, three essential processes for the establishment of viral infection and latency in blood T cells. It is the purpose of this review to examine, in detail, the manifestation of viral dependence on the actin cytoskeleton, and present a model of how HIV utilizes actin dynamics to initiate infection.
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Affiliation(s)
- Mark Spear
- National Center for Biodefense and Infectious Diseases, Department of Molecular and Microbiology, George Mason University, Manassas, VA 20110, USA
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Mascalchi P, Lamort AS, Salomé L, Dumas F. Single Particle Tracking reveals two distinct environments for CD4 receptors at the surface of living T lymphocytes. Biochem Biophys Res Commun 2011; 417:409-13. [PMID: 22166195 DOI: 10.1016/j.bbrc.2011.11.129] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 11/18/2011] [Indexed: 11/19/2022]
Abstract
We investigated the lateral diffusion of the HIV receptor CD4 at the surface of T lymphocytes at 20°C and 37°C by Single Particle Tracking using Quantum Dots. We found that the receptors presented two major distinct behaviors that were not equally affected by temperature changes. About half of the receptors showed a random diffusion with a diffusion coefficient increasing upon raising the temperature. The other half of the receptors was permanently or transiently confined with unchanged dynamics on raising the temperature. These observations suggest that two distinct subpopulations of CD4 receptors with different environments are present at the surface of living T lymphocytes.
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Affiliation(s)
- Patrice Mascalchi
- CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), Toulouse, France
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Abstract
PURPOSE OF REVIEW HIV-associated nephropathy (HIVAN) is characterized histologically by a collapsing form of focal segmental glomerulosclerosis (FSGS), microcystic tubular dilation, interstitial inflammation and fibrosis. In this review, we provide a summary of the current state of knowledge about the mechanisms involved in the pathogenesis of HIVAN. RECENT FINDINGS Two variants in the ApoL1 gene have been identified as the susceptibility alleles that account for a majority of the increased risk of FSGS and nondiabetic end-stage renal disease in blacks. HIVAN1 and HIVAN2 are the other host susceptibility genes that have been identified in animal models for HIVAN. HIV infects renal tubular epithelial cells likely through direct cell-cell transmission. Both in-vivo and in-vitro evidence suggests that Nef and Vpr are the key viral genes mediating HIVAN. Nef induces podocyte dysfunction, whereas Vpr induces renal tubular epithelial cell apoptosis. SUMMARY HIVAN results from direct infection by HIV-1 and expression of viral genes, especially Nef and Vpr, in renal epithelial cells in a genetically susceptible host. The infected renal epithelium acts as a separate viral compartment from the blood and facilitates evolution of strains distant from blood. Dysregulation of several host cellular pathways, including those involved in cell cycle and apoptosis, ultimately results in the unique histopathological syndrome of HIVAN.
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Potent and broad anti-HIV-1 activity exhibited by a glycosyl-phosphatidylinositol-anchored peptide derived from the CDR H3 of broadly neutralizing antibody PG16. J Virol 2011; 85:8467-76. [PMID: 21715497 DOI: 10.1128/jvi.00520-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
PG9 and PG16 are two recently isolated quaternary-specific human monoclonal antibodies that neutralize 70 to 80% of circulating HIV-1 isolates. The crystal structure of PG16 shows that it contains an exceptionally long CDR H3 that forms a unique stable subdomain that towers above the antibody surface to confer fine specificity. To determine whether this unique architecture of CDR H3 itself is sufficient for epitope recognition and neutralization, we cloned CDR H3 subdomains derived from human monoclonal antibodies PG16, PG9, b12, E51, and AVF and genetically linked them to a glycosyl-phosphatidylinositol (GPI) attachment signal. Each fusion gene construct is expressed and targeted to lipid rafts of plasma membranes through a GPI anchor. Moreover, GPI-CDR H3(PG16, PG9, and E51), but not GPI-CDR H3(b12 and AVF), specifically neutralized multiple clades of HIV-1 isolates with a great degree of potency when expressed on the surface of transduced TZM-bl cells. Furthermore, GPI-anchored CDR H3(PG16), but not GPI-anchored CDR H3(AVF), specifically confers resistance to HIV-1 infection when expressed on the surface of transduced human CD4(+) T cells. Finally, the CDR H3 mutations (Y100HF, D100IA, and G7) that were previously shown to compromise the neutralization activity of antibody PG16 also abolished the neutralization activity of GPI-CDR H3(PG16). Thus, we conclude that the CDR H3 subdomain of PG16 neutralizes HIV-1 when targeted to the lipid raft of the plasma membrane of HIV-1-susceptible cells and that GPI-CDR H3 can be an alternative approach for determining whether the CDR H3 of certain antibodies alone can exert epitope recognition and neutralization.
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Mulampaka SN, Dixit NM. Estimating the threshold surface density of Gp120-CCR5 complexes necessary for HIV-1 envelope-mediated cell-cell fusion. PLoS One 2011; 6:e19941. [PMID: 21647388 PMCID: PMC3103592 DOI: 10.1371/journal.pone.0019941] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 04/06/2011] [Indexed: 11/19/2022] Open
Abstract
Reduced expression of CCR5 on target CD4+ cells lowers their
susceptibility to infection by R5-tropic HIV-1, potentially preventing
transmission of infection and delaying disease progression. Binding of the HIV-1
envelope (Env) protein gp120 with CCR5 is essential for the entry of R5 viruses
into target cells. The threshold surface density of gp120-CCR5 complexes that
enables HIV-1 entry remains poorly estimated. We constructed a mathematical
model that mimics Env-mediated cell-cell fusion assays, where target
CD4+CCR5+ cells are exposed to effector
cells expressing Env in the presence of a coreceptor antagonist and the fraction
of target cells fused with effector cells is measured. Our model employs a
reaction network-based approach to describe protein interactions that precede
viral entry coupled with the ternary complex model to quantify the allosteric
interactions of the coreceptor antagonist and predicts the fraction of target
cells fused. By fitting model predictions to published data of cell-cell fusion
in the presence of the CCR5 antagonist vicriviroc, we estimated the threshold
surface density of gp120-CCR5 complexes for cell-cell fusion as ∼20
µm−2. Model predictions with this
threshold captured data from independent cell-cell fusion assays in the presence
of vicriviroc and rapamycin, a drug that modulates CCR5 expression, as well as
assays in the presence of maraviroc, another CCR5 antagonist, using sixteen
different Env clones derived from transmitted or early founder viruses. Our
estimate of the threshold surface density of gp120-CCR5 complexes necessary for
HIV-1 entry thus appears robust and may have implications for optimizing
treatment with coreceptor antagonists, understanding the non-pathogenic
infection of non-human primates, and designing vaccines that suppress the
availability of target CD4+CCR5+ cells.
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Affiliation(s)
| | - Narendra M. Dixit
- Department of Chemical Engineering, Indian
Institute of Science, Bangalore, India
- Bioinformatics Centre, Indian Institute of
Science, Bangalore, India
- * E-mail:
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Haughey NJ, Tovar-y-Romo LB, Bandaru VVR. Roles for biological membranes in regulating human immunodeficiency virus replication and progress in the development of HIV therapeutics that target lipid metabolism. J Neuroimmune Pharmacol 2011; 6:284-95. [PMID: 21445582 DOI: 10.1007/s11481-011-9274-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 03/08/2011] [Indexed: 01/14/2023]
Abstract
Infection by the human immunodeficiency virus (HIV) involves a number of important interactions with lipid components in host membranes that regulate binding, fusion, internalization, and viral assembly. Available data suggests that HIV actively modifies the sphingolipid content of cellular membranes to create focal environments that are favorable for infection. In this review, we summarize the roles that membrane lipids play in HIV infection and discuss the current status of therapeutics that attempt to modify biological membranes to inhibit HIV.
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Affiliation(s)
- Norman J Haughey
- Department of Neurology, Richard T. Johnson Division of Neuroimmunology and Neurological Infections, The Johns Hopkins University School of Medicine, Meyer 6-109, 600N. Wolfe Street, Baltimore, MD 21287, USA.
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26
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Arisaka M, Takano K, Negishi Y, Arima H, Aramaki Y. Involvement of lipid rafts in macrophage apoptosis induced by cationic liposomes. Arch Biochem Biophys 2011; 508:72-7. [PMID: 21315683 DOI: 10.1016/j.abb.2011.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 02/02/2011] [Accepted: 02/03/2011] [Indexed: 11/15/2022]
Abstract
We have demonstrated that protein kinase Cδ (PKCδ) could be involved in macrophage apoptosis induced by cationic liposomes composed of stearylamine (SA-liposomes), but the detailed mechanism of how SA-liposomes activate PKCδ has remained unclear. In this paper, we clarified whether lipid rafts are involved in the PKCδ activation induced by SA-liposomes. Co-localization of SA-liposomes and Cholera toxin B subunit (CBT), which specifically binds to ganglioside GM1 on lipid rafts, was found by microscopic observation. The incorporation of SA-liposomes into lipid rafts was clearly inhibited by the pretreatment of cells with an agent, 2,6-di-O-methyl-α-cyclodextrin (DM-α-CD) which disrupts lipid rafts. Activation of PKCδ and externalization of phosphatidylserine induced by SA-liposomes were also suppressed by DM-α-CD, which extracts sphingolipids and proteins from lipid rafts. Reactive oxygen species (ROS) generation, which could be involved in the macrophage apoptosis, was also inhibited by DM-α-CD. Furthermore, apoptosis induced by SA-liposomes was clearly inhibited when the cells were pre-treated with DM-α-CD, but not nystatin, a cholesterol-sequestering agent that disrupt lipid rafts. These findings suggest that sphingolipids in lipid rafts are involved in the activation of PKCδ which leads to apoptosis induced by cationic liposomes, SA-liposomes.
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Affiliation(s)
- Masaya Arisaka
- School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
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Carter GC, Bernstone L, Baskaran D, James W. HIV-1 infects macrophages by exploiting an endocytic route dependent on dynamin, Rac1 and Pak1. Virology 2011; 409:234-50. [DOI: 10.1016/j.virol.2010.10.018] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 10/04/2010] [Accepted: 10/13/2010] [Indexed: 01/12/2023]
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Gulzar N, Shroff A, Buberoglu B, Klonowska D, Kim JE, Copeland KFT. Properties of HTLV-I transformed CD8+ T-cells in response to HIV-1 infection. Virology 2010; 406:302-11. [PMID: 20708209 DOI: 10.1016/j.virol.2010.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 05/06/2010] [Accepted: 07/20/2010] [Indexed: 10/19/2022]
Abstract
HIV-1 infection studies of primary CD8(+) T-cells are hampered by difficulty in obtaining a significant number of targets for infection and low levels of productive infection. Further, there exists a paucity of CD8-expressing T-cell lines to address questions pertaining to the study of CD8(+) T-cells in the context of HIV-1 infection. In this study, a set of CD8(+) T-cell clones were originated through HTLV-I transformation in vitro, and the properties of these cells were examined. The clones were susceptible to T-cell tropic strains of the virus and exhibited HIV-1 production 20-fold greater than primary CD4(+) T-cells. Productive infection resulted in a decrease in expression of CD8 and CXCR4 molecules on the surface of the CD8(+) T-cell clones and antibodies to these molecules abrogated viral binding and replication. These transformed cells provide an important tool in the study of CD8(+) T-cells and may provide important insights into the mechanism(s) behind HIV-1 induced CD8(+) T-cell dysfunction.
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Affiliation(s)
- N Gulzar
- National HIV and Retrovirology Laboratories, Public Health Agency of Canada, Ottawa, Canada
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Wen M, Arora R, Wang H, Liu L, Kimata JT, Zhou P. GPI-anchored single chain Fv--an effective way to capture transiently-exposed neutralization epitopes on HIV-1 envelope spike. Retrovirology 2010; 7:79. [PMID: 20923574 PMCID: PMC2959034 DOI: 10.1186/1742-4690-7-79] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 10/06/2010] [Indexed: 12/22/2022] Open
Abstract
Background Identification of broad neutralization epitopes in HIV-1 envelope spikes is paramount for HIV-1 vaccine development. A few broad neutralization epitopes identified so far are present on the surface of native HIV-1 envelope spikes whose recognition by antibodies does not depend on conformational changes of the envelope spikes. However, HIV-1 envelope spikes also contain transiently-exposed neutralization epitopes, which are more difficult to identify. Results In this study, we constructed single chain Fvs (scFvs) derived from seven human monoclonal antibodies and genetically linked them with or without a glycosyl-phosphatidylinositol (GPI) attachment signal. We show that with a GPI attachment signal the scFvs are targeted to lipid rafts of plasma membranes. In addition, we demonstrate that four of the GPI-anchored scFvs, but not their secreted counterparts, neutralize HIV-1 with various degrees of breadth and potency. Among them, GPI-anchored scFv (X5) exhibits extremely potent and broad neutralization activity against multiple clades of HIV-1 strains tested. Moreover, we show that GPI-anchored scFv (4E10) also exhibited more potent neutralization activity than its secretory counterpart. Finally, we demonstrate that expression of GPI-anchored scFv (X5) in the lipid raft of plasma membrane of human CD4+ T cells confers long-term resistance to HIV-1 infection, HIV-1 envelope-mediated cell-cell fusion, and the infection of HIV-1 captured and transferred by human DCs. Conclusions Thus GPI-anchored scFv could be used as a general and effective way to identify antibodies that react with transiently-exposed neutralization epitopes in envelope proteins of HIV-1 and other enveloped viruses. The GPI-anchored scFv (X5), because of its breadth and potency, should have a great potential to be developed into anti-viral agent for HIV-1 prevention and therapy.
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Affiliation(s)
- Michael Wen
- The Unit of Anti-Viral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, 200025, China
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Fournier M, Peyrou M, Bourgoin L, Maeder C, Tchou I, Foti M. CD4 dimerization requires two cysteines in the cytoplasmic domain of the molecule and occurs in microdomains distinct from lipid rafts. Mol Immunol 2010; 47:2594-603. [DOI: 10.1016/j.molimm.2010.06.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 05/06/2010] [Accepted: 06/21/2010] [Indexed: 01/27/2023]
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Levental I, Grzybek M, Simons K. Greasing their way: lipid modifications determine protein association with membrane rafts. Biochemistry 2010; 49:6305-16. [PMID: 20583817 DOI: 10.1021/bi100882y] [Citation(s) in RCA: 299] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Increasing evidence suggests that biological membranes can be laterally subdivided into domains enriched in specific lipid and protein components and that these domains may be involved in the regulation of a number of vital cellular processes. An example is membrane rafts, which are lipid-mediated domains dependent on preferential association between sterols and sphingolipids and inclusive of a specific subset of membrane proteins. While the lipid and protein composition of rafts has been extensively characterized, the structural details determining protein partitioning to these domains remain unresolved. Here, we review evidence suggesting that post-translation modification by saturated lipids recruits both peripheral and transmembrane proteins to rafts, while short, unsaturated, and/or branched hydrocarbon chains prevent raft association. The most widely studied group of raft-associated proteins are glycophosphatidylinositol-anchored proteins (GPI-AP), and we review a variety of evidence supporting raft-association of these saturated lipid-anchored extracellular peripheral proteins. For transmembrane and intracellular peripheral proteins, S-acylation with saturated fatty acids mediates raft partitioning, and the dynamic nature of this modification presents an exciting possibility of enzymatically regulated raft association. The other common lipid modifications, that is, prenylation and myristoylation, are discussed in light of their likely role in targeting proteins to nonraft membrane regions. Finally, although the association between raft affinity and lipid modification is well-characterized, we discuss several open questions regarding regulation and remodeling of these post-translational modifications as well as their role in transbilayer coupling of membrane domains.
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Affiliation(s)
- Ilya Levental
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden, Germany
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32
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Míguez MJ, Lewis JE, Bryant VE, Rosenberg R, Burbano X, Fishman J, Asthana D, Duan R, Madhavan N, Malow RM. Low cholesterol? Don't brag yet ... hypocholesterolemia blunts HAART effectiveness: a longitudinal study. J Int AIDS Soc 2010; 13:25. [PMID: 20626901 PMCID: PMC2912249 DOI: 10.1186/1758-2652-13-25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 07/13/2010] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND In vitro studies suggest that reducing cholesterol inhibits HIV replication. However, this effect may not hold in vivo, where other factors, such as cholesterol's immunomodulatory properties, may interact. METHODS Fasting blood samples were obtained on 165 people living with HIV at baseline and after 24 weeks on highly active antiretroviral therapy (HAART). Participants were classified as hypocholesterolemic (HypoCHL; <150 mg/dl) or non-HypoCHL (>150 mg/dl) and were compared on viro-immune outcomes. RESULTS At baseline, participants with HypoCHL (40%) exhibited lower CD4 (197 +/- 181 vs. 295 +/- 191 cells/mm3, p = 0.02) and CD8 (823 +/- 448 vs. 1194 +/- 598 cells/mm3, p = 0.001) counts and were more likely to have detectable viral loads (OR = 3.5, p = 0.01) than non-HypoCHL controls. After HAART, participants with HypoCHL were twice as likely to experience a virological failure >400 copies (95% CI 1-2.6, p = 0.05) and to exhibit <200 CD4 (95% CI 1.03-2.9, p = 0.04) compared with non-HypoCHL. Low thymic output was related to poorer CD4 cell response in HypoCHL subjects. Analyses suggest a dose-response relationship with every increase of 50 mg/dl in cholesterol related to a parallel rise of 50 CD4 cells. CONCLUSIONS The study implicates, for the first time, HypoCHL with impaired HAART effectiveness, including limited CD4 repletion by the thymus and suboptimal viral clearance.
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Affiliation(s)
- María Jose Míguez
- Institute of Neuroimmune Pharmacology, Florida International University College of Medicine, Miami, FL, USA
- Department of Health Promotion and Disease Prevention, Robert Stempel College of Public Health and Social Work, and College of Medicine, Florida International University, Miami, FL, USA
| | - John E Lewis
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Vaughn E Bryant
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Rhonda Rosenberg
- Department of Health Promotion and Disease Prevention, Robert Stempel College of Public Health and Social Work, and College of Medicine, Florida International University, Miami, FL, USA
| | | | - Joel Fishman
- Department of Radiology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Deshratn Asthana
- Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Rui Duan
- Department of Health Promotion and Disease Prevention, Robert Stempel College of Public Health and Social Work, and College of Medicine, Florida International University, Miami, FL, USA
| | - Nair Madhavan
- Institute of Neuroimmune Pharmacology, Florida International University College of Medicine, Miami, FL, USA
| | - Robert M Malow
- Department of Health Promotion and Disease Prevention, Robert Stempel College of Public Health and Social Work, and College of Medicine, Florida International University, Miami, FL, USA
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Abstract
Retroviruses undergo several critical steps to complete a replication cycle. These include the complex processes of virus entry, assembly, and budding that often take place at the plasma membrane of the host cell. Both virus entry and release involve membrane fusion/fission reactions between the viral envelopes and host cell membranes. Accumulating evidence indicates important roles for lipids and lipid microdomains in virus entry and egress. In this review, we outline the current understanding of the role of lipids and membrane microdomains in retroviral replication.
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Response to ‘HIV-1 entry into human podocytes is mediated through lipid rafts’. Kidney Int 2010. [DOI: 10.1038/ki.2009.367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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35
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Abstract
Rafts are domains of the plasma membrane, enriched in cholesterol and sphingolipids; they form a platform for signaling proteins and receptors. The lipid rafts are utilized in the replication cycle of numerous viruses. Internalization receptors of many viruses localize to rafts or are recruited there after virus binding. Arrays of signal transduction proteins found in rafts contribute to efficient trafficking and productive infection. Some viruses are dependent on raft domains for the biogenesis of their membranous replication structures. Finally, rafts are often important in virus assembly and budding. Subsequently, raft components in the viral envelope may be vital for the entry to a new host cell. Here, we summarize the current knowledge of the involvement of rafts in virus infection.
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Affiliation(s)
- Paula Upla
- Department of Biological & Environmental Science/Nanoscience Center, University of Jyväskylä, FI-40351 Jyväskylä, Finland
| | - Timo Hyypiä
- Department of Virology, University of Turku, FI-20520 Turku, Finland
| | - Varpu Marjomäki
- Department of Biological & Environmental Science/Nanoscience Center, University of Jyväskylä, FI-40351 Jyväskylä, Finland
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Kamiyama H, Yoshii H, Tanaka Y, Sato H, Yamamoto N, Kubo Y. Raft localization of CXCR4 is primarily required for X4-tropic human immunodeficiency virus type 1 infection. Virology 2009; 386:23-31. [PMID: 19178925 DOI: 10.1016/j.virol.2008.12.033] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 11/10/2008] [Accepted: 12/17/2008] [Indexed: 11/16/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) infection is initiated by successive interactions of viral envelope glycoprotein gp120 with two cellular surface proteins, CD4 and chemokine receptor. The two most common chemokine receptors that allow HIV-1 entry are the CCR5 and CXCR4. The CD4 and CCR5 are mainly localized to the particular plasma membrane microdomains, termed raft, which is rich in glycolipids and cholesterol. However, the CXCR4 is localized only partially to the raft region. Although the raft domain is suggested to participate in HIV-1 infection, its role in entry of CXCR4-tropic (X4-tropic) virus is still unclear. Here, we used a combination of CD4-independent infection system and cholesterol-depletion-inducing reagent, methyl-beta-cyclodextrin (MbetaCD), to address the requirement of raft domain in the X4-tropic virus infection. Treatment of CD4-negative, CXCR4-positive human cells with MbetaCD inhibited CD4-independent infection of the X4-tropic strains. This inhibitory effect of the cholesterol depletion was observed even when the CXCR4 was over-expressed on the target cells. Soluble CD4-induced infection was also inhibited by MbetaCD. The MbetaCD had no effect on the levels of cell surface expression of CXCR4. In contrast to these infections, MbetaCD treatment did not inhibit CD4-dependent HIV-1 infection in the wild type CD4-expressing cells. This study and previous reports showing that CD4 mutants localized to non-raft domains function as HIV-1 receptor indicate that CXCR4 clustering in the raft microdomains, rather than CD4, is the key step for the HIV-1 entry.
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Affiliation(s)
- Haruka Kamiyama
- Department of AIDS Research, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523, Japan
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Carter GC, Bernstone L, Sangani D, Bee JW, Harder T, James W. HIV entry in macrophages is dependent on intact lipid rafts. Virology 2009; 386:192-202. [PMID: 19185899 PMCID: PMC7103383 DOI: 10.1016/j.virol.2008.12.031] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 11/18/2008] [Accepted: 12/22/2008] [Indexed: 01/30/2023]
Abstract
Macrophages are an important natural target cell for HIV-1, but previous studies of virus entry into these cells are limited, and the involvement of membrane cholesterol and lipid rafts is unknown. Cholesterol disruption of macrophage membranes using four pharmacological agents acting by different mechanisms: methyl-β cyclodextrin, nystatin, filipin complex and Lovastatin, all significantly inhibited productive HIV entry and reverse transcription. The inhibitory effects of these drugs resulted in decreased virus release from infected cells, and could be substantially reversed by the addition of water-soluble cholesterol. The virus bound equally to cholesterol-disrupted cells even though HIV receptor expression levels were significantly reduced. Macrophage CD4 and CCR5 were found to partition with the detergent-resistant membranes with a typical raft-associating protein flotillin-1. HIV particles were observed co-localising with a marker of lipid rafts (CTB-FITC) early post infection. These data suggest that macrophage membrane cholesterol is essential for HIV entry, and implicate lipid raft involvement.
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Affiliation(s)
- Gemma C Carter
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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39
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Identification of the LWYIK motif located in the human immunodeficiency virus type 1 transmembrane gp41 protein as a distinct determinant for viral infection. J Virol 2008; 83:870-83. [PMID: 18987155 DOI: 10.1128/jvi.01088-08] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The highly conserved LWYIK motif located immediately proximal to the membrane-spanning domain of the gp41 transmembrane protein of human immunodeficiency virus type 1 has been proposed as being important for the surface envelope (Env) glycoprotein's association with lipid rafts and gp41-mediated membrane fusion. Here we employed substitution and deletion mutagenesis to understand the role of this motif in the virus life cycle. None of the mutants examined affected the synthesis, precursor processing, CD4 binding, oligomerization, or cell surface expression of the Env, nor did they alter Env incorporation into the virus. All of the mutants, particularly the DeltaYI, DeltaIK, and DeltaLWYIK mutants, in which the indicated residues were deleted, exhibited greatly reduced one-cycle viral replication and the Env trans-complementation ability. All of these deletion mutant proteins were still localized in the lipid rafts. With the exception of the Trp-to-Ala (WA) mutant, which exhibited reduced viral infectivity albeit with normal membrane fusion, all mutants displayed loss of some or almost all of the membrane fusion ability. Although these deletion mutants partially inhibited in trans wild-type (WT) Env-mediated fusion, they were more effective in dominantly interfering with WT Env-mediated viral entry when coexpressed with the WT Env, implying a role of this motif in postfusion events as well. Both T20 and L43L peptides derived from the two gp41 extracellular C- and N-terminal alpha-helical heptad repeats, respectively, inhibited WT and DeltaLWYIK Env-mediated viral entry with comparable efficacies. Biotin-tagged T20 effectively captured both the fusion-active, prehairpin intermediates of WT and mutant gp41 upon CD4 activation. Env without the deletion of the LWYIK motif still effectively mediated lipid mixing but inhibited content mixing. Our study demonstrates that the immediate membrane-proximal LWYIK motif acts as a unique and distinct determinant located in the gp41 C-terminal ectodomain by promoting enlargement of fusion pores and postfusion activities.
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40
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Chan CM, Woo PCY, Lau SKP, Tse H, Chen HL, Li F, Zheng BJ, Chen L, Huang JD, Yuen KY. Spike protein, S, of human coronavirus HKU1: role in viral life cycle and application in antibody detection. Exp Biol Med (Maywood) 2008; 233:1527-36. [PMID: 18849544 DOI: 10.3181/0806-rm-197] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We recently described the discovery, genome, clinical features, genotypes and evolution of a novel and global human respiratory virus named human coronavirus HKU1 (HCoV-HKU1) which is not yet culturable. We expressed a C-terminal FLAG-tagged CoV-HKU1 spike (S) protein by the Semliki Forest Virus (SFV) system and investigated its maturation profile. Pulse chase labeling revealed that S-FLAG was expressed as high-mannose N-glycans of monomers and trimers. It was predominantly cleaved into subdomains S1 and S2 during maturation. S1 was secreted into the medium. Immunofluorescence analysis visualized S along the secretory pathway from endoplasmic reticulum to plasma membrane. Cleavage of S and release of HCoV-HKU1 S pseudotyped virus were inhibited by furin or furin-like enzyme inhibitors. The cell-based expressed full-length S-FLAG could be recognized by the convalescent serum obtained from a patient with HCoV-HKU1 pneumonia. The data suggest that the native form of HCoV-HKU1 spike expressed in our system can be used in developing serological diagnostic assay and in understanding the role of S in the viral life cycle.
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Affiliation(s)
- Che-Man Chan
- Department of Microbiology, The University of Hong Kong, Hong Kong Special Administration Region, Hong Kong
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41
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Kobe F, Renner U, Woehler A, Wlodarczyk J, Papusheva E, Bao G, Zeug A, Richter DW, Neher E, Ponimaskin E. Stimulation- and palmitoylation-dependent changes in oligomeric conformation of serotonin 5-HT1A receptorsi. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1503-16. [DOI: 10.1016/j.bbamcr.2008.02.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/21/2008] [Accepted: 02/25/2008] [Indexed: 12/01/2022]
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42
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Pontier SM, Percherancier Y, Galandrin S, Breit A, Galés C, Bouvier M. Cholesterol-dependent separation of the beta2-adrenergic receptor from its partners determines signaling efficacy: insight into nanoscale organization of signal transduction. J Biol Chem 2008; 283:24659-72. [PMID: 18566454 DOI: 10.1074/jbc.m800778200] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Determining the role of lipid raft nanodomains in G protein-coupled receptor signaling remains fraught by the lack of assays directly monitoring rafts in native membranes. We thus combined extensive biochemical and pharmacological approaches to a nanoscale strategy based on bioluminescence resonance energy transfer (BRET) to assess the spatial and functional influence of cholesterol-rich liquid-ordered lipid nanodomains on beta2 adrenergic receptor (beta2AR) signaling. The data revealed that whereas beta2AR did not partition within liquid-ordered lipid phase, a pool of G protein and adenylyl cyclase (AC) were sequestered in these domains. Destabilization of the liquid-ordered phase by cholesterol depletion led to a lateral redistribution of Galphas and AC that favored interactions between the receptor and its signaling partners as assessed by BRET. This resulted in an increased basal and agonist-promoted beta2AR-stimulated cAMP production that was partially dampened as a result of constitutive protein kinase A-dependent phosphorylation and desensitization of the receptor. This restraining influence of nanodomains on beta2AR signaling was further substantiated by showing that liquid-ordered lipid phase stabilization using caveolin overexpression or increasing membrane cholesterol amount led to an inhibition of beta2AR-associated signaling. Given the emerging concept that clustering of receptors and effectors into signaling platforms contributes to the efficacy and selectivity of signal transduction, our results support a model whereby cholesterol-promoted liquid-ordered lipid phase-embedding Gs and AC allows their lateral separation from the receptor, thus restraining the basal activity and controlling responsiveness of beta2AR signaling machinery within larger signaling platforms.
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Affiliation(s)
- Stéphanie M Pontier
- Institut de Recherche en Immunologie et Cancérologie, Département de Biochimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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43
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Mulari MT, Nars M, Laitala-Leinonen T, Kaisto T, Metsikkö K, Sun Y, Väänänen HK. Recombinant VSV G proteins reveal a novel raft-dependent endocytic pathway in resorbing osteoclasts. Exp Cell Res 2008; 314:1641-51. [DOI: 10.1016/j.yexcr.2008.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Revised: 02/10/2008] [Accepted: 02/15/2008] [Indexed: 10/22/2022]
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44
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Rawat SS, Zimmerman C, Johnson BT, Cho E, Lockett SJ, Blumenthal R, Puri A. Restricted lateral mobility of plasma membrane CD4 impairs HIV-1 envelope glycoprotein mediated fusion. Mol Membr Biol 2008; 25:83-94. [PMID: 18097956 DOI: 10.1080/09687680701613713] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We investigated the effect of receptor mobility on HIV-1 envelope glycoprotein (Env)-triggered fusion using B16 mouse melanoma cells that are engineered to express CD4 and CXCR4 or CCR5. These engineered cells are resistant to fusion mediated CD4-dependent HIV-1 envelope glycoprotein. Receptor mobility was measured by fluorescence recovery after photobleaching (FRAP) using either fluorescently-labeled antibodies or transient expression of GFP-tagged receptors in the cells. No significant differences between B16 and NIH3T3 (fusion-permissive) cells were seen in lateral mobility of CCR5 or lipid probes. By contrast CD4 mobility in B16 cells was about seven-fold reduced compared to its mobility in fusion-permissive NIH3T3 cells. However, a CD4 mutant (RA5) that localizes to non-raft membrane microdomains exhibited a three-fold increased mobility in B16 cells as compared with WT-CD4. Interestingly, the B16 cells expressing the RA5 mutant (but not the wild type CD4) and coreceptors supported HIV-1 Env-mediated fusion. Our data demonstrate that the lateral mobility of CD4 is an important determinant of HIV-1 fusion/entry.
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Affiliation(s)
- Satinder S Rawat
- CCRNP, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702-1201, USA
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45
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Jin H, McCaffery JM, Grote E. Ergosterol promotes pheromone signaling and plasma membrane fusion in mating yeast. ACTA ACUST UNITED AC 2008; 180:813-26. [PMID: 18299351 PMCID: PMC2265586 DOI: 10.1083/jcb.200705076] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Ergosterol depletion independently inhibits two aspects of yeast mating: pheromone signaling and plasma membrane fusion. In signaling, ergosterol participates in the recruitment of Ste5 to a polarized site on the plasma membrane. Ergosterol is thought to form microdomains within the membrane by interacting with the long acyl chains of sphingolipids. We find that although sphingolipid-free ergosterol is concentrated at sites of cell–cell contact, transmission of the pheromone signal at contact sites depends on a balanced ratio of ergosterol to sphingolipids. If a mating pair forms between ergosterol-depleted cells despite the attenuated pheromone response, the subsequent process of membrane fusion is retarded. Prm1 also participates in membrane fusion. However, ergosterol and Prm1 have independent functions and only prm1 mutant mating pairs are susceptible to contact-dependent lysis. In contrast to signaling, plasma membrane fusion is relatively insensitive to sphingolipid depletion. Thus, the sphingolipid-free pool of ergosterol promotes plasma membrane fusion.
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Affiliation(s)
- Hui Jin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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46
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Bukrinsky M, Sviridov D. Human immunodeficiency virus infection and macrophage cholesterol metabolism. J Leukoc Biol 2007; 80:1044-51. [PMID: 17056763 DOI: 10.1189/jlb.0206113] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Macrophages play a central role in the pathogenesis of atherosclerosis and are also a host for a number of viruses, most importantly, HIV. Many viruses, including HIV, require cholesterol for their replication and as a structural element. Cholesterol also plays a pivotal role in innate antiviral immune responses. Although impairing innate immune response by increasing cell cholesterol content may be a deliberate strategy used by a pathogen to improve its infectivity, enhancing the risk of atherosclerosis is likely a byproduct. Consistent association between HIV infection and elevated risk of atherosclerosis suggested a connection between virus-induced changes in cholesterol metabolism and atherogenesis, but the mechanisms of such connection have not been identified. We describe in this review various mechanisms enabling viruses to exploit macrophage pathways of cholesterol metabolism, thus diverting cholesterol for a purpose of increasing viral replication and/or for altering innate immune responses. To alter the cellular cholesterol content, viruses "hijack" the pathways responsible for maintaining intracellular cholesterol metabolism. The damage to these pathways by viral infection may result in the inability of macrophages to control cholesterol accumulation and may lead to formation of foam cells, a characteristic feature of atherosclerosis. Further elucidation of the mechanisms connecting viral infection and macrophage cholesterol metabolism may be fruitful for developing approaches to treatment of atherosclerosis and viral diseases.
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Affiliation(s)
- Michael Bukrinsky
- Department of Microbiology, Immunology and Tropical Medicine, 2300 I St., N.W., Ross Hall, Rm. 234, Washington, DC 20037, USA.
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47
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Brügger B, Krautkrämer E, Tibroni N, Munte CE, Rauch S, Leibrecht I, Glass B, Breuer S, Geyer M, Kräusslich HG, Kalbitzer HR, Wieland FT, Fackler OT. Human immunodeficiency virus type 1 Nef protein modulates the lipid composition of virions and host cell membrane microdomains. Retrovirology 2007; 4:70. [PMID: 17908312 PMCID: PMC2065869 DOI: 10.1186/1742-4690-4-70] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 10/01/2007] [Indexed: 01/03/2023] Open
Abstract
Background The Nef protein of Human Immunodeficiency Viruses optimizes viral spread in the infected host by manipulating cellular transport and signal transduction machineries. Nef also boosts the infectivity of HIV particles by an unknown mechanism. Recent studies suggested a correlation between the association of Nef with lipid raft microdomains and its positive effects on virion infectivity. Furthermore, the lipidome analysis of HIV-1 particles revealed a marked enrichment of classical raft lipids and thus identified HIV-1 virions as an example for naturally occurring membrane microdomains. Since Nef modulates the protein composition and function of membrane microdomains we tested here if Nef also has the propensity to alter microdomain lipid composition. Results Quantitative mass spectrometric lipidome analysis of highly purified HIV-1 particles revealed that the presence of Nef during virus production from T lymphocytes enforced their raft character via a significant reduction of polyunsaturated phosphatidylcholine species and a specific enrichment of sphingomyelin. In contrast, Nef did not significantly affect virion levels of phosphoglycerolipids or cholesterol. The observed alterations in virion lipid composition were insufficient to mediate Nef's effect on particle infectivity and Nef augmented virion infectivity independently of whether virus entry was targeted to or excluded from membrane microdomains. However, altered lipid compositions similar to those observed in virions were also detected in detergent-resistant membrane preparations of virus producing cells. Conclusion Nef alters not only the proteome but also the lipid composition of host cell microdomains. This novel activity represents a previously unrecognized mechanism by which Nef could manipulate HIV-1 target cells to facilitate virus propagation in vivo.
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Affiliation(s)
- Britta Brügger
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | | | - Nadine Tibroni
- Abteilung Virologie, Universität Heidelberg, Heidelberg, Germany
| | - Claudia E Munte
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Regensburg, Germany
| | - Susanne Rauch
- Abteilung Virologie, Universität Heidelberg, Heidelberg, Germany
| | - Iris Leibrecht
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Bärbel Glass
- Abteilung Virologie, Universität Heidelberg, Heidelberg, Germany
| | - Sebastian Breuer
- Max-Planck-Institut für molekulare Physiologie, Abteilung Physikalische Biochemie, Dortmund, Germany
| | - Matthias Geyer
- Max-Planck-Institut für molekulare Physiologie, Abteilung Physikalische Biochemie, Dortmund, Germany
| | | | - Hans Robert Kalbitzer
- Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Regensburg, Germany
| | - Felix T Wieland
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Oliver T Fackler
- Abteilung Virologie, Universität Heidelberg, Heidelberg, Germany
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48
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Teissier É, Pécheur EI. Lipids as modulators of membrane fusion mediated by viral fusion proteins. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:887-99. [PMID: 17882414 PMCID: PMC7080115 DOI: 10.1007/s00249-007-0201-z] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 05/17/2007] [Accepted: 06/11/2007] [Indexed: 11/24/2022]
Abstract
Enveloped viruses infect host cells by fusion of viral and target membranes. This fusion event is triggered by specific glycoproteins in the viral envelope. Fusion glycoproteins belong to either class I, class II or the newly described third class, depending upon their arrangement at the surface of the virion, their tri-dimensional structure and the location within the protein of a short stretch of hydrophobic amino acids called the fusion peptide, which is able to induce the initial lipid destabilization at the onset of fusion. Viral fusion occurs either with the plasma membrane for pH-independent viruses, or with the endosomal membranes for pH-dependent viruses. Although, viral fusion proteins are parted in three classes and the subcellular localization of fusion might vary, these proteins have to act, in common, on lipid assemblies. Lipids contribute to fusion through their physical, mechanical and/or chemical properties. Lipids can thus play a role as chemically defined entities, or through their preferential partitioning into membrane microdomains called “rafts”, or by modulating the curvature of the membranes involved in the fusion process. The purpose of this review is to make a state of the art on recent findings on the contribution of cholesterol, sphingolipids and glycolipids in cell entry and membrane fusion of a number of viral families, whose members bear either class I or class II fusion proteins, or fusion proteins of the recently discovered third class.
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Affiliation(s)
- Élodie Teissier
- Structural NMR and Bioinformatics, UMR CNRS 5086, Institut de Biologie et Chimie des Protéines, IFR 128 BioSciences Lyon-Gerland, 7 passage du Vercors, 69367 Lyon, France
| | - Eve-Isabelle Pécheur
- Structural NMR and Bioinformatics, UMR CNRS 5086, Institut de Biologie et Chimie des Protéines, IFR 128 BioSciences Lyon-Gerland, 7 passage du Vercors, 69367 Lyon, France
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49
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Baker AM, Saulière A, Gaibelet G, Lagane B, Mazères S, Fourage M, Bachelerie F, Salomé L, Lopez A, Dumas F. CD4 interacts constitutively with multiple CCR5 at the plasma membrane of living cells. A fluorescence recovery after photobleaching at variable radii approach. J Biol Chem 2007; 282:35163-8. [PMID: 17855336 DOI: 10.1074/jbc.m705617200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The entry of human immunodeficiency virus into target cells requires successive interactions of the viral envelope glycoprotein gp120 with CD4 and the chemokine receptors CCR5 or CXCR4. We previously demonstrated, by Förster resonance energy transfer experiments, the constitutive association of CD4 and CCR5 at the surface of living cells. We therefore speculated that this interaction may correlate with compartmentalization of CD4 and CCR5 within the plasma membrane. Here, we characterize the lateral distribution, the dynamics, and the stoichiometry of these receptors in living cells stably expressing CD4 and/or CCR5 by means of fluorescence recovery after photobleaching at variable radii experiments. We found that (i) these receptors expressed alone are confined into 1-microm-sized domains, (ii) CD4-CCR5 associations occur outside and inside smaller domains, and (iii) these interactions involve multiple CCR5 molecules per CD4.
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Affiliation(s)
- Aurélie-Marie Baker
- Institut de Pharmacologie et Biologie Structurale, UMR CNRS-Université Paul Sabatier 5089, 205 Route de Narbonne, 31062 Toulouse cedex, France
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Pang DJ, Hayday AC, Bijlmakers MJ. CD8 Raft Localization Is Induced by Its Assembly into CD8αβ Heterodimers, Not CD8αα Homodimers. J Biol Chem 2007; 282:13884-94. [PMID: 17341584 DOI: 10.1074/jbc.m701027200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The coreceptor CD8 is expressed as a CD8alphabeta heterodimer on major histocompatibility complex class I-restricted TCRalphabeta T cells, and as a CD8alphaalpha homodimer on subsets of memory T cells, intraepithelial lymphocytes, natural killer cells, and dendritic cells. Although the role of CD8alphaalpha is not well understood, it is increasingly clear that this protein is not a functional homologue of CD8alphabeta. On major histocompatibility complex class I-restricted T cells, CD8alphabeta is a more efficient TCR coreceptor than CD8alphaalpha. This property has for the mouse protein been attributed to the recruitment of CD8alphabeta into lipid rafts, which is dependent on CD8beta palmitoylation. Here, these divergent distributions of CD8alphabeta and CD8alphaalpha are demonstrated for the human CD8 proteins as well. However, although palmitoylation of both CD8alpha and CD8beta chains was detected, this modification did not contribute to raft localization. In contrast, arginines in the cytoplasmic domain are crucial for raft localization of CD8betabeta. Most strikingly, the assembly of a non-raft localized CD8beta chain with a non-raft localized CD8alpha chain resulted in raft-localized CD8alphabeta heterodimers. Using chimeric CD8 proteins, this property of the heterodimer was found to be determined by the assembly of CD8alpha and CD8beta extracellular regions. The presence of two CD8alpha extracellular regions, on the other hand, appears to preclude raft localization. Thus, heterodimer formation and raft association are intimately linked for CD8alphabeta. These results emphasize that lipid raft localization is a key feature of human CD8alphabeta that clearly distinguishes it from CD8alphaalpha.
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MESH Headings
- CD8 Antigens/genetics
- CD8 Antigens/immunology
- CD8-Positive T-Lymphocytes/immunology
- Cell Line
- Dendritic Cells/immunology
- Dimerization
- Histocompatibility Antigens Class I/genetics
- Histocompatibility Antigens Class I/immunology
- Humans
- Immunologic Memory/genetics
- Killer Cells, Natural/immunology
- Membrane Microdomains/genetics
- Membrane Microdomains/immunology
- Palmitic Acid/immunology
- Protein Processing, Post-Translational/genetics
- Protein Processing, Post-Translational/immunology
- Protein Structure, Tertiary/genetics
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
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Affiliation(s)
- Dick John Pang
- Peter Gorer Department of Immunobiology, King's College London, School of Medicine at Guy's Hospital, London SE1 9RT, United Kingdom
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