1
|
Dam KMA, Fan C, Yang Z, Bjorkman PJ. Intermediate conformations of CD4-bound HIV-1 Env heterotrimers. Nature 2023; 623:1017-1025. [PMID: 37993719 PMCID: PMC10686819 DOI: 10.1038/s41586-023-06639-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 09/13/2023] [Indexed: 11/24/2023]
Abstract
HIV-1 envelope (Env) exhibits distinct conformational changes in response to host receptor (CD4) engagement. Env, a trimer of gp120 and gp41 heterodimers, has been structurally characterized in a closed, prefusion conformation with closely associated gp120s and coreceptor binding sites on gp120 V3 hidden by V1V2 loops1-4 and in fully saturated CD4-bound open Env conformations with changes including outwardly rotated gp120s and displaced V1V2 loops3-9. To investigate changes resulting from substoichiometric CD4 binding, we solved single-particle cryo-electron microscopy (cryo-EM) structures of soluble, native-like heterotrimeric Envs bound to one or two CD4 molecules. Most of the Env trimers bound to one CD4 adopted the closed, prefusion Env state, with a minority exhibiting a heterogeneous partially open Env conformation. When bound to two CD4s, the CD4-bound gp120s exhibited an open Env conformation including a four-stranded gp120 bridging sheet and displaced gp120 V1V2 loops that expose the coreceptor sites on V3. The third gp120 adopted an intermediate, occluded-open state10 that showed gp120 outward rotation but maintained the prefusion three-stranded gp120 bridging sheet with only partial V1V2 displacement and V3 exposure. We conclude that most of the engagements with one CD4 molecule were insufficient to stimulate CD4-induced conformational changes, whereas binding two CD4 molecules led to Env opening in CD4-bound protomers only. The substoichiometric CD4-bound soluble Env heterotrimer structures resembled counterparts derived from a cryo-electron tomography study of complexes between virion-bound Envs and membrane-anchored CD4 (ref. 11), validating their physiological relevance. Together, these results illuminate intermediate conformations of HIV-1 Env and illustrate its structural plasticity.
Collapse
Affiliation(s)
- Kim-Marie A Dam
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Chengcheng Fan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Zhi Yang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
| |
Collapse
|
2
|
Dam KMA, Fan C, Yang Z, Bjorkman PJ. Structural characterization of HIV-1 Env heterotrimers bound to one or two CD4 receptors reveals intermediate Env conformations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.27.525985. [PMID: 36747804 PMCID: PMC9900888 DOI: 10.1101/2023.01.27.525985] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
HIV-1 envelope (Env) exhibits distinct conformational changes in response to host receptor (CD4) engagement. Env, a trimer of gp120/gp41 heterodimers, has been structurally characterized in a closed, prefusion conformation with closely associated gp120s and coreceptor binding sites on gp120 V3 hidden by V1V2 loops, and in fully-saturated CD4-bound open Env conformations with changes including outwardly rotated gp120s and displaced V1V2 loops. To investigate changes resulting from sub-stoichiometric CD4 binding, we solved 3.4Å and 3.9Å single-particle cryo-EM structures of soluble, native-like Envs bound to one or two CD4 molecules. Env trimer bound to one CD4 adopted the closed, prefusion Env state. When bound to two CD4s, the CD4-bound gp120s exhibited an open Env conformation including a four-stranded gp120 bridging sheet and displaced gp120 V1V2 loops that expose the coreceptor sites on V3. The third gp120 adopted an intermediate, occluded-open state that included gp120 outward rotation but maintained the prefusion, three-stranded gp120 bridging sheet and showed only partial V1V2 displacement and V3 exposure. We conclude that engagement of one CD4 molecule was insufficient to stimulate CD4-induced conformational changes, while binding two CD4 molecules led to Env opening in CD4-bound protomers only. Together, these results illuminate HIV-1 Env intermediate conformations and illustrate the structural plasticity of HIV-1 Env.
Collapse
Affiliation(s)
- Kim-Marie A Dam
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Chengcheng Fan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Zhi Yang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Present address: Department of Molecular and Cell Biology, University of California, 13 Berkeley, CA 94720, USA
| | - Pamela J Bjorkman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| |
Collapse
|
3
|
Bibollet-Ruche F, Russell RM, Liu W, Stewart-Jones GBE, Sherrill-Mix S, Li Y, Learn GH, Smith AG, Gondim MVP, Plenderleith LJ, Decker JM, Easlick JL, Wetzel KS, Collman RG, Ding S, Finzi A, Ayouba A, Peeters M, Leendertz FH, van Schijndel J, Goedmakers A, Ton E, Boesch C, Kuehl H, Arandjelovic M, Dieguez P, Murai M, Colin C, Koops K, Speede S, Gonder MK, Muller MN, Sanz CM, Morgan DB, Atencia R, Cox D, Piel AK, Stewart FA, Ndjango JBN, Mjungu D, Lonsdorf EV, Pusey AE, Kwong PD, Sharp PM, Shaw GM, Hahn BH. CD4 receptor diversity in chimpanzees protects against SIV infection. Proc Natl Acad Sci U S A 2019; 116:3229-3238. [PMID: 30718403 PMCID: PMC6386711 DOI: 10.1073/pnas.1821197116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Human and simian immunodeficiency viruses (HIV/SIVs) use CD4 as the primary receptor to enter target cells. Here, we show that the chimpanzee CD4 is highly polymorphic, with nine coding variants present in wild populations, and that this diversity interferes with SIV envelope (Env)-CD4 interactions. Testing the replication fitness of SIVcpz strains in CD4+ T cells from captive chimpanzees, we found that certain viruses were unable to infect cells from certain hosts. These differences were recapitulated in CD4 transfection assays, which revealed a strong association between CD4 genotypes and SIVcpz infection phenotypes. The most striking differences were observed for three substitutions (Q25R, Q40R, and P68T), with P68T generating a second N-linked glycosylation site (N66) in addition to an invariant N32 encoded by all chimpanzee CD4 alleles. In silico modeling and site-directed mutagenesis identified charged residues at the CD4-Env interface and clashes between CD4- and Env-encoded glycans as mechanisms of inhibition. CD4 polymorphisms also reduced Env-mediated cell entry of monkey SIVs, which was dependent on at least one D1 domain glycan. CD4 allele frequencies varied among wild chimpanzees, with high diversity in all but the western subspecies, which appeared to have undergone a selective sweep. One allele was associated with lower SIVcpz prevalence rates in the wild. These results indicate that substitutions in the D1 domain of the chimpanzee CD4 can prevent SIV cell entry. Although some SIVcpz strains have adapted to utilize these variants, CD4 diversity is maintained, protecting chimpanzees against infection with SIVcpz and other SIVs to which they are exposed.
Collapse
Affiliation(s)
| | - Ronnie M Russell
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Weimin Liu
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Guillaume B E Stewart-Jones
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Scott Sherrill-Mix
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Yingying Li
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Gerald H Learn
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Andrew G Smith
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Marcos V P Gondim
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Lindsey J Plenderleith
- Institute of Evolutionary Biology, University of Edinburgh, EH9 3FL Edinburgh, United Kingdom
- Centre for Immunity, Infection and Evolution, University of Edinburgh, EH9 3FL Edinburgh, United Kingdom
| | - Julie M Decker
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Juliet L Easlick
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Katherine S Wetzel
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Ronald G Collman
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Shilei Ding
- Département de Microbiologie, Infectiologie et Immunologie, Centre de Recherche du Centre Hospitalier de L'Université de Montréal, Montréal, QC H2X0A9, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, QC H2X0A9, Canada
| | - Andrés Finzi
- Département de Microbiologie, Infectiologie et Immunologie, Centre de Recherche du Centre Hospitalier de L'Université de Montréal, Montréal, QC H2X0A9, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, QC H2X0A9, Canada
| | - Ahidjo Ayouba
- Recherche Translationnelle Appliquée au VIH et aux Maladies Infectieuses, Institut de Recherche pour le Développement, University of Montpellier, INSERM, 34090 Montpellier, France
| | - Martine Peeters
- Recherche Translationnelle Appliquée au VIH et aux Maladies Infectieuses, Institut de Recherche pour le Développement, University of Montpellier, INSERM, 34090 Montpellier, France
| | - Fabian H Leendertz
- Research Group Epidemiology of Highly Pathogenic Microorganisms, Robert Koch Institute, 13353 Berlin, Germany
| | - Joost van Schijndel
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
- Chimbo Foundation, 1011 PW Amsterdam, The Netherlands
| | | | - Els Ton
- Chimbo Foundation, 1011 PW Amsterdam, The Netherlands
| | - Christophe Boesch
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Hjalmar Kuehl
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Mimi Arandjelovic
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Paula Dieguez
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Mizuki Murai
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Christelle Colin
- Projet Primates France, Centre de Conservation pour Chimpanzés, BP 36 Faranah, Republic of Guinea
| | - Kathelijne Koops
- Department of Anthropology, University of Zurich, CH-8006 Zurich, Switzerland
| | - Sheri Speede
- Sanaga-Yong Chimpanzee Rescue Center, In Defense of Animals-Africa, Portland, OR 97204
| | - Mary K Gonder
- Department of Biology, Drexel University, Philadelphia, PA 19104
| | - Martin N Muller
- Department of Anthropology, University of New Mexico, Albuquerque, NM 87131
| | - Crickette M Sanz
- Department of Anthropology, Washington University in St. Louis, St Louis, MO 63130
- Congo Program, Wildlife Conservation Society, BP 14537 Brazzaville, Republic of the Congo
| | - David B Morgan
- Congo Program, Wildlife Conservation Society, BP 14537 Brazzaville, Republic of the Congo
- Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL 60614
| | - Rebecca Atencia
- Tchimpounga Chimpanzee Rehabilitation Center, The Jane Goodall Institute-Congo, BP 1206 Pointe Noire, Republic of Congo
| | - Debby Cox
- Tchimpounga Chimpanzee Rehabilitation Center, The Jane Goodall Institute-Congo, BP 1206 Pointe Noire, Republic of Congo
- Africa Programs, The Jane Goodall Institute, Vienna, VA 22182
| | - Alex K Piel
- School of Natural Sciences and Psychology, Liverpool John Moores University, L3 3AF Liverpool, United Kingdom
| | - Fiona A Stewart
- School of Natural Sciences and Psychology, Liverpool John Moores University, L3 3AF Liverpool, United Kingdom
| | - Jean-Bosco N Ndjango
- Department of Ecology and Management of Plant and Animal Resources, Faculty of Sciences, University of Kisangani, BP 2012 Kisangani, Democratic Republic of the Congo
| | - Deus Mjungu
- Gombe Stream Research Centre, The Jane Goodall Institute, Kigoma, Tanzania
| | | | - Anne E Pusey
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Paul M Sharp
- Institute of Evolutionary Biology, University of Edinburgh, EH9 3FL Edinburgh, United Kingdom
- Centre for Immunity, Infection and Evolution, University of Edinburgh, EH9 3FL Edinburgh, United Kingdom
| | - George M Shaw
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Beatrice H Hahn
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104;
- Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104
| |
Collapse
|
4
|
Ivan B, Sun Z, Subbaraman H, Friedrich N, Trkola A. CD4 occupancy triggers sequential pre-fusion conformational states of the HIV-1 envelope trimer with relevance for broadly neutralizing antibody activity. PLoS Biol 2019; 17:e3000114. [PMID: 30650070 PMCID: PMC6351000 DOI: 10.1371/journal.pbio.3000114] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 01/29/2019] [Accepted: 01/04/2019] [Indexed: 12/18/2022] Open
Abstract
During the entry process, the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer undergoes a sequence of conformational changes triggered by both CD4 and coreceptor engagement. Resolving the conformation of these transient entry intermediates has proven challenging. Here, we fine-mapped the antigenicity of entry intermediates induced by increasing CD4 engagement of cell surface–expressed Env. Escalating CD4 triggering led to the sequential adoption of different pre-fusion conformational states of the Env trimer, up to the pre-hairpin conformation, that we assessed for antibody epitope presentation. Maximal accessibility of the coreceptor binding site was detected below Env saturation by CD4. Exposure of the fusion peptide and heptad repeat 1 (HR1) required higher CD4 occupancy. Analyzing the diverse antigenic states of the Env trimer, we obtained key insights into the transitions in epitope accessibility of broadly neutralizing antibodies (bnAbs). Several bnAbs preferentially bound CD4-triggered Env, indicating a potential capacity to neutralize both pre- and post-CD4 engagement, which needs to be explored. Assessing binding and neutralization activity of bnAbs, we confirm antibody dissociation rates as a driver of incomplete neutralization. Collectively, our findings highlight a need to resolve Env conformations that are neutralization-relevant to provide guidance for immunogen development. Comprehensive mapping of conformational stages adopted by the HIV‐1 envelope glycoprotein trimer during entry into the cell reveals the preference of broadly neutralizing antibodies for distinct pre-fusion states of the trimer. The trimeric human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) mediates HIV-1 entry into its target cells. Entry is initiated by sequential triggering of Env upon interaction with its primary receptor CD4 and a coreceptor on target cells. The ensuing structural rearrangements of the Env trimer bring the viral membrane in close vicinity of the cellular membrane, enabling fusion. Resolving the structural differences between the consecutive conformations Env adopts during the entry process is of high interest, as different antigenic domains are exposed, which may affect the capacity of neutralizing antibodies to bind to Env and inhibit entry. Here, we compared the conformation of unliganded closed Env with the transitional CD4-bound Env forms by studying the antigenicity of cell surface–expressed Env with and without CD4 triggering. We show that incremental triggering by soluble CD4 allows the capture of the full continuum of conformational changes, including events that follow coreceptor interaction. Thus, the setup we introduce here turns a simple binding assay into a powerful tool to study transitional conformation changes in HIV-1 Env. Analyzing the capacity of Env-reactive antibodies to recognize the diverse Env stages, our study reveals novel aspects of the binding preferences of neutralizing antibodies that affect their inhibitory activity.
Collapse
Affiliation(s)
- Branislav Ivan
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Zhaozhi Sun
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Harini Subbaraman
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Nikolas Friedrich
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
- * E-mail:
| |
Collapse
|
5
|
Wang L, Izadmehr S, Kamau E, Kong XP, Chen BK. Sequential trafficking of Env and Gag to HIV-1 T cell virological synapses revealed by live imaging. Retrovirology 2019; 16:2. [PMID: 30646921 PMCID: PMC6334456 DOI: 10.1186/s12977-019-0464-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 01/07/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND HIV infection is enhanced by cell adhesions that form between infected and uninfected T cells called virological synapses (VS). VS are initiated by an interaction between Env and CD4 on cell surfaces and result in the recruitment of virus assembly to the site of cell-cell contact. However, the recruitment of Env to the VS and its relationship to Gag recruitment is not well defined. RESULTS To study the trafficking of HIV-1 Env through the VS, we constructed a molecular clone of HIV carrying a green fluorescent protein-Env fusion protein called, HIV Env-isfGFP-∆V1V2. The Env-isfGFP-∆V1V2 fusion protein does not produce virus particles on its own, but can be rescued by cotransfection with full-length HIV constructs and produce virus particles that package the fluorescent Env. These rescued fluorescent Env can participate in VS formation and can be used to directly image CD4-dependent Env transfer across VS from donor to target cells. The movements of fluorescently tagged Gag and Env to the VS and transfer into target cells can be also tracked through live imaging. Time lapse live imaging reveals evidence of limited Env accumulation at the site of cell-cell contact shortly after cell adhesion, followed by Gag re-distribution to contact area. Both Gag and Env can be recruited to form button-like spots characteristic of VS. CONCLUSIONS Env and Gag are recruited to the VS in a coordinated temporal sequence and subsequently transfer together across the synapse into the target cell. Env accumulations, when observed, are earlier than Gag re-distribution to the contact area during formation of VS.
Collapse
Affiliation(s)
- Lili Wang
- 0000 0001 0670 2351grid.59734.3cDepartment of Medicine, Division of Infectious Diseases, Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029 USA
| | - Sudeh Izadmehr
- 0000 0001 0670 2351grid.59734.3cDepartment of Medicine, Division of Infectious Diseases, Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029 USA
| | - Edwin Kamau
- 0000 0004 1936 8753grid.137628.9Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016 USA
| | - Xiang-Peng Kong
- 0000 0004 1936 8753grid.137628.9Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016 USA
| | - Benjamin K. Chen
- 0000 0001 0670 2351grid.59734.3cDepartment of Medicine, Division of Infectious Diseases, Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029 USA
| |
Collapse
|
6
|
Ma X, Lu M, Gorman J, Terry DS, Hong X, Zhou Z, Zhao H, Altman RB, Arthos J, Blanchard SC, Kwong PD, Munro JB, Mothes W. HIV-1 Env trimer opens through an asymmetric intermediate in which individual protomers adopt distinct conformations. eLife 2018; 7:e34271. [PMID: 29561264 PMCID: PMC5896952 DOI: 10.7554/elife.34271] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 03/20/2018] [Indexed: 01/02/2023] Open
Abstract
HIV-1 entry into cells requires binding of the viral envelope glycoprotein (Env) to receptor CD4 and coreceptor. Imaging of individual Env molecules on native virions shows Env trimers to be dynamic, spontaneously transitioning between three distinct well-populated conformational states: a pre-triggered Env (State 1), a default intermediate (State 2) and a three-CD4-bound conformation (State 3), which can be stabilized by binding of CD4 and coreceptor-surrogate antibody 17b. Here, using single-molecule Fluorescence Resonance Energy Transfer (smFRET), we show the default intermediate configuration to be asymmetric, with individual protomers adopting distinct conformations. During entry, this asymmetric intermediate forms when a single CD4 molecule engages the trimer. The trimer can then transition to State 3 by binding additional CD4 molecules and coreceptor.
Collapse
Affiliation(s)
- Xiaochu Ma
- Department of Microbial PathogenesisYale University School of MedicineNew HavenUnited States
| | - Maolin Lu
- Department of Microbial PathogenesisYale University School of MedicineNew HavenUnited States
| | - Jason Gorman
- Vaccine Research Center, National Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaUnited States
| | - Daniel S Terry
- Department of Physiology and BiophysicsWeill Cornell Medical College of Cornell UniversityNew YorkUnited States
| | - Xinyu Hong
- Department of Microbial PathogenesisYale University School of MedicineNew HavenUnited States
| | - Zhou Zhou
- Department of Physiology and BiophysicsWeill Cornell Medical College of Cornell UniversityNew YorkUnited States
| | - Hong Zhao
- Department of Physiology and BiophysicsWeill Cornell Medical College of Cornell UniversityNew YorkUnited States
| | - Roger B Altman
- Department of Physiology and BiophysicsWeill Cornell Medical College of Cornell UniversityNew YorkUnited States
| | - James Arthos
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaUnited States
| | - Scott C Blanchard
- Department of Physiology and BiophysicsWeill Cornell Medical College of Cornell UniversityNew YorkUnited States
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious DiseasesNational Institutes of HealthBethesdaUnited States
| | - James B Munro
- Department of Molecular Biology and MicrobiologyTufts University School of MedicineBostonUnited States
| | - Walther Mothes
- Department of Microbial PathogenesisYale University School of MedicineNew HavenUnited States
| |
Collapse
|
7
|
Espy N, Pacheco B, Sodroski J. Adaptation of HIV-1 to cells with low expression of the CCR5 coreceptor. Virology 2017; 508:90-107. [PMID: 28521215 DOI: 10.1016/j.virol.2017.04.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 11/19/2022]
Abstract
The binding of the human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer ((gp120/gp41)3) to the receptors CD4 and CCR5 triggers virus entry into host cells. To identify Env regions that respond to CCR5 binding, HIV-1 was serially passaged on a CD4-positive canine cell line expressing progressively lower levels of CCR5. HIV-1 replication was observed in cells expressing ~1300 CCR5 molecules/cell. Env changes that conferred this low-CCR5 replication phenotype were located outside of the known CCR5-binding region of the gp120 Env subunit and did not apparently increase CCR5 binding affinity. The adaptation-associated changes, located in the gp120 α1 helix and in the gp41 HR1 heptad repeat and membrane-proximal external region (MPER), enhanced HIV-1 replication in cells at all levels of CCR5 expression. The adapted Envs exhibited a greater propensity to undergo conformational changes, as evidenced by increased exposure of conserved regions near the CD4- and CCR5-binding sites.
Collapse
Affiliation(s)
- Nicole Espy
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Beatriz Pacheco
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Joseph Sodroski
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
8
|
Khasnis MD, Halkidis K, Bhardwaj A, Root MJ. Receptor Activation of HIV-1 Env Leads to Asymmetric Exposure of the gp41 Trimer. PLoS Pathog 2016; 12:e1006098. [PMID: 27992602 PMCID: PMC5222517 DOI: 10.1371/journal.ppat.1006098] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/09/2017] [Accepted: 11/29/2016] [Indexed: 11/18/2022] Open
Abstract
Structural rearrangements of HIV-1 glycoprotein Env promote viral entry through membrane fusion. Env is a symmetric homotrimer with each protomer composed of surface subunit gp120 and transmembrane subunit gp41. Cellular CD4- and chemokine receptor-binding to gp120 coordinate conformational changes in gp41, first to an extended prehairpin intermediate (PHI) and, ultimately, into a fusogenic trimer-of-hairpins (TOH). HIV-1 fusion inhibitors target gp41 in the PHI and block TOH formation. To characterize structural transformations into and through the PHI, we employed asymmetric Env trimers containing both high and low affinity binding sites for individual fusion inhibitors. Asymmetry was achieved using engineered Env heterotrimers composed of protomers deficient in either CD4- or chemokine receptor-binding. Linking receptor engagement to inhibitor affinity allowed us to assess conformational changes of individual Env protomers in the context of a functioning trimer. We found that the transition into the PHI could occur symmetrically or asymmetrically depending on the stoichiometry of CD4 binding. Sequential engagement of multiple CD4s promoted progressive exposure of individual fusion inhibitor binding sites in a CD4-dependent fashion. By contrast, engagement of only a single CD4 molecule led to a delayed, but symmetric, exposure of the gp41 trimer. This complex coupling between Env-CD4 interaction and gp41 exposure explained the multiphasic fusion-inhibitor titration observed for a mutant Env homotrimer with a naturally asymmetric gp41. Our results suggest that the spatial and temporal exposure of gp41 can proceed in a nonconcerted, asymmetric manner depending on the number of CD4s that engage the Env trimer. The findings have important implications for the mechanism of viral membrane fusion and the development of vaccine candidates designed to elicit neutralizing antibodies targeting gp41 in the PHI. For HIV, cellular invasion requires merging viral and cellular membranes, an event achieved through the activity of the viral fusion protein Env. Env consists of three gp120 and three gp41 subunits symmetrically arranged on the viral surface. The gp120 subunits bind cellular receptors, which, in turn, coordinate gp41 conformational changes that promote membrane fusion. Understanding these structural rearrangements illuminates the mechanism of viral membrane fusion, and also spurs development of targeted inhibitors of viral entry and vaccine candidates that elicit antiviral immune responses. In this study, we employed a novel strategy to investigate individual subunits in the context of functioning Env complexes. The strategy links distinct gp120-receptor interactions to conformational changes that expose specific gp41 subunits. We found that, despite the initial symmetric arrangement of its subunits, Env conformational changes most often proceed quite asymmetrically, leading to exposure of only one-third of the gp41 trimer for much of the fusion event. This finding might explain why attempts to elicit potent anti-HIV antibodies to a fully exposed gp41 trimer have been largely unsuccessful. The study gives us a glimpse of the early structural transitions leading to Env-mediated membrane fusion and provides a framework for interrogating the fusion proteins of other membrane-encapsulated viruses.
Collapse
Affiliation(s)
- Mukta D. Khasnis
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States of America
| | - Konstantine Halkidis
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States of America
| | - Anshul Bhardwaj
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States of America
| | - Michael J. Root
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States of America
- * E-mail:
| |
Collapse
|
9
|
HIV-1 Escape from a Peptidic Anchor Inhibitor through Stabilization of the Envelope Glycoprotein Spike. J Virol 2016; 90:10587-10599. [PMID: 27654295 DOI: 10.1128/jvi.01616-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 08/31/2016] [Indexed: 12/17/2022] Open
Abstract
The trimeric HIV-1 envelope glycoprotein spike (Env) mediates viral entry into cells by using a spring-loaded mechanism that allows for the controlled insertion of the Env fusion peptide into the target membrane, followed by membrane fusion. Env is the focus of vaccine research aimed at inducing protective immunity by antibodies as well as efforts to develop drugs that inhibit the viral entry process. The molecular factors contributing to Env stability and decay need to be understood better in order to optimally design vaccines and therapeutics. We generated viruses with resistance to VIR165, a peptidic inhibitor that binds the fusion peptide of the gp41 subunit and prevents its insertion into the target membrane. Interestingly, a number of escape viruses acquired substitutions in the C1 domain of the gp120 subunit (A60E, E64K, and H66R) that rendered these viruses dependent on the inhibitor. These viruses could infect target cells only when VIR165 was present after CD4 binding. Furthermore, the VIR165-dependent viruses were resistant to soluble CD4-induced Env destabilization and decay. These data suggest that VIR165-dependent Env proteins are kinetically trapped in the unliganded state and require the drug to negotiate CD4-induced conformational changes. These studies provide mechanistic insight into the action of the gp41 fusion peptide and its inhibitors and provide new ways to stabilize Env trimer vaccines. IMPORTANCE Because of the rapid development of HIV-1 drug resistance, new drug targets need to be explored continuously. The fusion peptide of the envelope glycoprotein can be targeted by anchor inhibitors. Here we describe virus escape from the anchor inhibitor VIR165. Interestingly, some escape viruses became dependent on the inhibitor for cell entry. We show that the identified escape mutations stabilize the ground state of the envelope glycoprotein and should thus be useful in the design of stabilized envelope-based HIV vaccines.
Collapse
|
10
|
Zarr M, Siliciano R. Stoichiometric parameters of HIV-1 entry. Virology 2014; 474:1-9. [PMID: 25463598 DOI: 10.1016/j.virol.2014.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/30/2014] [Accepted: 10/07/2014] [Indexed: 11/27/2022]
Abstract
During HIV type 1 (HIV-1) entry, trimers of gp120 bind to CD4 and either the CCR5 or CXCR4 coreceptor on the target cell. The stoichiometric parameters associated with HIV-1 entry remain unclear. Important unanswered questions include: how many trimers must attach to CD4 molecules, how many must bind coreceptors, and how many functional gp120 subunits per trimer are required for entry? We performed single round infectivity assays with chimeric viruses and compared the experimental relative infectivity curves with curves generated by mathematical models. Our results indicate that HIV-1 entry requires only a small number of functional spikes (one or two), that Env trimers may function with fewer than three active subunits, and that there is no major difference in the stoichiometric requirements for CCR5 vs. CXCR4 mediated HIV-1 entry into host cells.
Collapse
Affiliation(s)
- Melissa Zarr
- Johns Hopkins University School of Medicine, 733 N Broadway, Room 872, Baltimore, MD 21205, USA.
| | - Robert Siliciano
- Johns Hopkins University School of Medicine, 733 N Broadway, Room 872, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Baltimore, MD, USA.
| |
Collapse
|
11
|
Kim AS, Leaman DP, Zwick MB. Antibody to gp41 MPER alters functional properties of HIV-1 Env without complete neutralization. PLoS Pathog 2014; 10:e1004271. [PMID: 25058619 PMCID: PMC4110039 DOI: 10.1371/journal.ppat.1004271] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 06/11/2014] [Indexed: 01/08/2023] Open
Abstract
Human antibody 10E8 targets the conserved membrane proximal external region (MPER) of envelope glycoprotein (Env) subunit gp41 and neutralizes HIV-1 with exceptional potency. Remarkably, HIV-1 containing mutations that reportedly knockout 10E8 binding to linear MPER peptides are partially neutralized by 10E8, producing a local plateau in the dose response curve. Here, we found that virus partially neutralized by 10E8 becomes significantly less neutralization sensitive to various MPER antibodies and to soluble CD4 while becoming significantly more sensitive to antibodies and fusion inhibitors against the heptad repeats of gp41. Thus, 10E8 modulates sensitivity of Env to ligands both pre- and post-receptor engagement without complete neutralization. Partial neutralization by 10E8 was influenced at least in part by perturbing Env glycosylation. With unliganded Env, 10E8 bound with lower apparent affinity and lower subunit occupancy to MPER mutant compared to wild type trimers. However, 10E8 decreased functional stability of wild type Env while it had an opposite, stabilizing effect on MPER mutant Envs. Clade C isolates with natural MPER polymorphisms also showed partial neutralization by 10E8 with altered sensitivity to various gp41-targeted ligands. Our findings suggest a novel mechanism of virus neutralization by demonstrating how antibody binding to the base of a trimeric spike cross talks with adjacent subunits to modulate Env structure and function. The ability of an antibody to stabilize, destabilize, partially neutralize as well as alter neutralization sensitivity of a virion spike pre- and post-receptor engagement may have implications for immunotherapy and vaccine design.
Collapse
Affiliation(s)
- Arthur S. Kim
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Daniel P. Leaman
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Michael B. Zwick
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
| |
Collapse
|
12
|
Rocha-Perugini V, Gordon-Alonso M, Sánchez-Madrid F. PIP2: choreographer of actin-adaptor proteins in the HIV-1 dance. Trends Microbiol 2014; 22:379-88. [PMID: 24768560 DOI: 10.1016/j.tim.2014.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/11/2014] [Accepted: 03/25/2014] [Indexed: 02/06/2023]
Abstract
The actin cytoskeleton plays a key role during the replication cycle of human immunodeficiency virus-1 (HIV-1). HIV-1 infection is affected by cellular proteins that influence the clustering of viral receptors or the subcortical actin cytoskeleton. Several of these actin-adaptor proteins are controlled by the second messenger phosphatidylinositol 4,5-biphosphate (PIP2), an important regulator of actin organization. PIP2 production is induced by HIV-1 attachment and facilitates viral infection. However, the importance of PIP2 in regulating cytoskeletal proteins and thus HIV-1 infection has been overlooked. This review examines recent reports describing the roles played by actin-adaptor proteins during HIV-1 infection of CD4+ T cells, highlighting the influence of the signaling lipid PIP2 in this process.
Collapse
Affiliation(s)
- Vera Rocha-Perugini
- Servicio de Inmunología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria de la Princesa, Madrid, Spain; Vascular Biology and Inflammation Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Mónica Gordon-Alonso
- Servicio de Inmunología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria de la Princesa, Madrid, Spain
| | - Francisco Sánchez-Madrid
- Servicio de Inmunología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria de la Princesa, Madrid, Spain; Vascular Biology and Inflammation Department, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
| |
Collapse
|
13
|
Pereira LE, Clark J, Grznarova P, Wen X, LaCasse R, Ruml T, Spearman P, Hunter E. Direct evidence for intracellular anterograde co-transport of M-PMV Gag and Env on microtubules. Virology 2013; 449:109-19. [PMID: 24418544 DOI: 10.1016/j.virol.2013.11.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/14/2013] [Accepted: 11/04/2013] [Indexed: 12/25/2022]
Abstract
The intracellular transport of Mason-Pfizer monkey virus (M-PMV) assembled capsids from the pericentriolar region to the plasma membrane (PM) requires trafficking of envelope glycoprotein (Env) to the assembly site via the recycling endosome. However, it is unclear if Env-containing vesicles play a direct role in trafficking capsids to the PM. Using live cell microscopy, we demonstrate, for the first time, anterograde co-transport of Gag and Env. Nocodazole disruption of microtubules had differential effects on Gag and Env trafficking, with pulse-chase assays showing a delayed release of Env-deficient virions. Particle tracking demonstrated an initial loss of linear movement of GFP-tagged capsids and mCherry-tagged Env, followed by renewed movement of Gag but not Env at 4h post-treatment. Thus, while delayed capsid trafficking can occur in the absence of microtubules, efficient anterograde transport of capsids appears to be mediated by microtubule-associated Env-containing vesicles.
Collapse
Affiliation(s)
- Lara E Pereira
- Emory Vaccine Center, Yerkes National Primate Research Center, 954 Gatewood Road NE, Atlanta, GA 30329, USA.
| | - Jasmine Clark
- Emory Vaccine Center, Yerkes National Primate Research Center, 954 Gatewood Road NE, Atlanta, GA 30329, USA.
| | - Petra Grznarova
- Department of Biochemistry and Microbiology, Institute of Chemical Technology, Technicka 3, 166 28 Prague, Czech Republic.
| | - Xiaoyun Wen
- Department of Pediatrics, Emory University School of Medicine, 2015 Uppergate Drive, Atlanta, GA 30322, USA.
| | - Rachel LaCasse
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT, USA.
| | - Tomas Ruml
- Department of Biochemistry and Microbiology, Institute of Chemical Technology, Technicka 3, 166 28 Prague, Czech Republic.
| | - Paul Spearman
- Department of Pediatrics, Emory University School of Medicine, 2015 Uppergate Drive, Atlanta, GA 30322, USA.
| | - Eric Hunter
- Emory Vaccine Center, Yerkes National Primate Research Center, 954 Gatewood Road NE, Atlanta, GA 30329, USA.
| |
Collapse
|
14
|
Abstract
Infection of cells by enveloped viruses requires merger of the viral envelope membrane with target cell membranes, resulting in the formation of fusion pores through which the viral genome is released. Since lipid membranes do not mix spontaneously, the fusion process is energy-dependent and mediated by viral envelope glycoprotein complexes. Based on their structural and mechanistic properties, three distinct classes of viral fusion proteins have been identified to date. Despite their diversity, basic principles of viral membrane fusion, simultaneous engagement of both donor and target membrane and refolding into hairpin-like structures, have emerged as universally conserved. This article provides an overview of the basic principles of viral membrane fusion common to all enveloped viruses and discusses the specific structural and functional features of the different fusion protein classes by example of the paramyxovirus, flavivirus and rhabdovirus families.
Collapse
|
15
|
Abstract
Virions of the Human Immunodeficiency Virus (HIV) infect cells by first attaching with their surface spikes to the CD4 receptor on target cells. This leads to conformational changes in the viral spikes, enabling the virus to engage a coreceptor, commonly CCR5 or CXCR4, and consecutively to insert the fusion peptide into the cellular membrane. Finally, the viral and the cellular membranes fuse. The HIV spike is a trimer consisting of three identical heterodimers composed of the gp120 and gp41 envelope proteins. Each of the gp120 proteins in the trimer is capable of attaching to the CD4 receptor and the coreceptor, and each of the three gp41 units harbors a fusion domain. It is still under debate how many of the envelope subunits within a given trimer have to bind to the CD4 receptors and to the coreceptors, and how many gp41 protein fusion domains are required for fusion. These numbers are referred to as subunit stoichiometries. We present a mathematical framework for estimating these parameters individually by analyzing infectivity assays with pseudotyped viruses. We find that the number of spikes that are engaged in mediating cell entry and the distribution of the spike number play important roles for the estimation of the subunit stoichiometries. Our model framework also shows why it is important to subdivide the question of the number of functional subunits within one trimer into the three different subunit stoichiometries. In a second step, we extend our models to study whether the subunits within one trimer cooperate during receptor binding and fusion. As an example for how our models can be applied, we reanalyze a data set on subunit stoichiometries. We find that two envelope proteins have to engage with CD4-receptors and coreceptors and that two fusion proteins must be revealed within one trimer for viral entry. Our study is motivated by the mechanism of HIV entry but the experimental technique and the model framework can be extended to other viral systems as well.
Collapse
|
16
|
Nonacs P, Kapheim KM. Modeling Disease Evolution with Multilevel Selection: HIV as a Quasispecies Social Genome. ACTA ACUST UNITED AC 2012. [DOI: 10.4303/jem/235553] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
17
|
Liu L, Cimbro R, Lusso P, Berger EA. Intraprotomer masking of third variable loop (V3) epitopes by the first and second variable loops (V1V2) within the native HIV-1 envelope glycoprotein trimer. Proc Natl Acad Sci U S A 2011; 108:20148-53. [PMID: 22128330 PMCID: PMC3250183 DOI: 10.1073/pnas.1104840108] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Within the trimeric HIV-1 envelope (Env) spike, the first and second variable loops (V1V2 region) and the third variable loop (V3) of the gp120 subunit play dual roles in antibody recognition, because they contain neutralization epitopes and also participate in epitope masking. The spatial relationships between V1V2 and V3 and the associated mechanisms of epitope masking remain unclear. Here we investigated interactions between these domains using two monoclonal antibodies recognizing distinct conserved linear epitopes that are subject to masking in the functional trimer, which limits their neutralizing activities. Using Env pseudotype virus infection assays, we found that deleting the V1V2 region greatly enhanced neutralization by both antibodies, leading us to consider two alternative models: V1V2 on one gp120 protomer masks V3 on the same protomer (intraprotomer or cis masking) versus on an adjacent protomer (interprotomer or trans masking). Our experimental approach exploited a previously described complementation system wherein two variant Envs harboring different inactivating mutations (one in gp120, the other in gp41) are coexpressed in the same cell; functional Env results only from cooperative interactions within mixed trimers, thereby enabling selective examination of mixed trimer activity. We introduced additional mutations that either promoted (V1V2 deletion, i.e., unmasking) or prevented (GPGR to GPGQ mutation, i.e., epitope destruction) interaction with the antibodies. The observed neutralization sensitivities of mixed trimers produced from various combinations of constructs support the intraprotomer (cis) model of V1V2 masking of V3 epitopes.
Collapse
Affiliation(s)
- Li Liu
- Laboratories of Viral Diseases and
| | - Raffaello Cimbro
- Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Paolo Lusso
- Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | | |
Collapse
|
18
|
Anastassopoulou CG, Ketas TJ, Depetris RS, Thomas AM, Klasse PJ, Moore JP. Resistance of a human immunodeficiency virus type 1 isolate to a small molecule CCR5 inhibitor can involve sequence changes in both gp120 and gp41. Virology 2011; 413:47-59. [PMID: 21356539 DOI: 10.1016/j.virol.2010.12.052] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 09/15/2010] [Accepted: 12/27/2010] [Indexed: 10/18/2022]
Abstract
Here, we describe the genetic pathways taken by a human immunodeficiency virus type 1 (HIV-1) isolate, D101.12, to become resistant to the small molecule CCR5 inhibitor, vicriviroc (VCV), in vitro. Resistant D101.12 variants contained at least one substitution in the gp120 V3 region (H308P), plus one of two patterns of gp41 sequence changes involving the fusion peptide (FP) and a downstream residue: G514V+V535M or M518V+F519L+V535M. Studies of Env-chimeric and point-substituted viruses in peripheral blood mononuclear cells (PBMC) and TZM-bl cells showed that resistance can arise from the cooperative action of gp120 and gp41 changes, while retaining CCR5 usage. Modeling the VCV inhibition data from the two cell types suggests that D101.12 discriminates between high- and low-VCV affinity forms of CCR5 less than D1/85.16, a resistant virus with three FP substitutions.
Collapse
Affiliation(s)
- Cleo G Anastassopoulou
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA.
| | | | | | | | | | | |
Collapse
|
19
|
Melikyan GB. Membrane fusion mediated by human immunodeficiency virus envelope glycoprotein. CURRENT TOPICS IN MEMBRANES 2011; 68:81-106. [PMID: 21771496 DOI: 10.1016/b978-0-12-385891-7.00004-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Gregory B Melikyan
- Department of Pediatrics, Infectious Diseases, Emory University, Atlanta, GA, USA
| |
Collapse
|