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Tateishi H, Chinen T, Fukuda R, Radwan MO, Shimagaki K, Koga R, Masuda T, Okamoto Y, Sakamoto A, Misumi S, Otsuka M, Fujita M, Anraku K. HIV-1 Gag MA domain binds to cardiolipin in a binding mode distinct from virus assemble mediator PI(4,5)P 2. Chem Biol Drug Des 2024; 103:e14401. [PMID: 37985015 DOI: 10.1111/cbdd.14401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/16/2023] [Accepted: 11/07/2023] [Indexed: 11/22/2023]
Abstract
The human immunodeficiency virus type 1 (HIV-1) Gag protein is responsible for facilitating HIV-1 virion assembly and budding. Our study demonstrates that cardiolipin (CL), a component found in the inner mitochondrial membrane, exhibits the highest binding affinity to the N-terminal MA domain of the HIV-1 Gag protein within the lipid group of host cells. To assess this binding interaction, we synthesized short acyl chain derivatives of CL and employed surface plasmon resonance (SPR) analysis to determine the dissociation constants (Kd) for CL and the MA domain. Simultaneously, we examined the Kd of D-myo-phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 ) derivatives, known to play a crucial role in virion formation. Among all the derivatives, Tetra-C7 -CL exhibited the lowest Kd value (Kd = 30.8 ± 6.9 μM) for MA binding on the CL analog-immobilized sensorchip, indicating a higher affinity. Similarly, the Kd value of Di-C7 -PIP2 (Kd = 36.6 ± 4.7 μM) was the lowest on the PI(4,5)P2 analog-immobilized sensorchip. Thus, Tetra-C7 -CL binds to the MA domain using a distinct binding mode while displaying a comparable binding affinity to Di-C7 -PIP2. This discovery holds significant implications for comprehending the virological importance of CL-MA domain binding, such as its subcellular distribution, including mitochondrial translocation, and involvement in viral particle formation in concert with PI(4,5)P2 . Furthermore, this study has the potential to contribute to the development of drugs in the future.
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Affiliation(s)
- Hiroshi Tateishi
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takuma Chinen
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Ryota Fukuda
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Mohamed O Radwan
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Chemistry of Natural Compounds Department, Pharmaceutical and Drug Industries Research Division, National Research Centre, Cairo, Egypt
| | - Kazunori Shimagaki
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Ryoko Koga
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takashi Masuda
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yoshinari Okamoto
- Department of Instrumental Analysis, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Arisa Sakamoto
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Department of Medical Technology, Kumamoto Health Science University, Kumamoto, Japan
| | - Shogo Misumi
- Department of Environmental and Molecular Health Sciences, Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masami Otsuka
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Science Farm Ltd., Kumamoto, Japan
| | - Mikako Fujita
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kensaku Anraku
- Department of Medical Technology, Kumamoto Health Science University, Kumamoto, Japan
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2
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Sumner C, Kotani O, Liu S, Musier-Forsyth K, Sato H, Ono A. Molecular Determinants in tRNA D-arm Required for Inhibition of HIV-1 Gag Membrane Binding. J Mol Biol 2022; 434:167390. [PMID: 34883117 PMCID: PMC8752508 DOI: 10.1016/j.jmb.2021.167390] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 11/23/2021] [Accepted: 11/30/2021] [Indexed: 02/01/2023]
Abstract
Plasma-membrane-specific localization of Gag, an essential step in HIV-1 particle assembly, is regulated by the interaction of the Gag MA domain with PI(4,5)P2 and tRNA-mediated inhibition of non-specific or premature membrane binding. Different tRNAs inhibit PI(4,5)P2-independent membrane binding to varying degrees in vitro; however, the structural determinants for this difference remain unknown. Here we demonstrate that membrane binding of full-length Gag synthesized in vitro using reticulocyte lysates is inhibited when RNAs that contain the anticodon arm of tRNAPro, but not that of tRNALys3, are added exogenously. In contrast, in the context of a liposome binding assay in which the effects of tRNAs on purified MA were tested, full-length tRNALys3 showed greater inhibition of MA membrane binding than full-length tRNAPro. While transplantation of the D loop sequence of tRNALys3 into tRNAPro resulted in a modest increase in the inhibitory effect relative to WT tRNAPro, replacing the entire D arm sequence with that of tRNALys3 was necessary to confer the full inhibitory effects upon tRNAPro. Together, these results demonstrate that the D arm of tRNALys3 is a major determinant of strong inhibition of MA membrane binding and that this inhibitory effect requires not only the D loop, which was recently reported to contact the MA highly basic region, but the loop sequence in the context of the D arm structure.
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Affiliation(s)
- Christopher Sumner
- Dept. of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United States
| | - Osamu Kotani
- Center for Pathogen Genomics, National Institute of Infectious Diseases, Tokyo, Japan
| | - Shuohui Liu
- Dept. of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Karin Musier-Forsyth
- Dept. of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Hironori Sato
- Center for Pathogen Genomics, National Institute of Infectious Diseases, Tokyo, Japan
| | - Akira Ono
- Dept. of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United States
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3
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Raut P, Waters H, Zimmberberg J, Obeng B, Gosse J, Hess ST. Localization-Based Super-Resolution Microscopy Reveals Relationship between SARS-CoV2 Spike and Phosphatidylinositol (4,5)-bisphosphate. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2022; 11965:1196503. [PMID: 36051945 PMCID: PMC9432428 DOI: 10.1117/12.2613460] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Localization microscopy circumvents the diffraction limit by identifying and measuring the positions of numerous subsets of individual fluorescent molecules, ultimately producing an image whose resolution depends on the uncertainty and density of localization, and whose capabilities are compatible with imaging living specimens. Spectral resolution can be improved by incorporating a dichroic or dispersive element in the detection path of a localization microscope, which can be useful for separation of multiple probes imaged simultaneously and for detection of changes in emission spectra of fluorophores resulting from changes in their environment. These methodological advances enable new biological applications, which in turn motivate new questions and technical innovations. As examples, we present fixed-cell imaging of the spike protein SARS-CoV2 (S) and its interactions with host cell components. Results show a relationship between S and the lipid phosphatidylinositol (4,5)-bisphosphate (PIP2). These findings have ramifications for several existing models of plasma membrane organization.
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Affiliation(s)
- Prakash Raut
- Department of Physics and Astronomy, University of Maine, Orono, ME 04469-5709
| | - Hang Waters
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1855
| | - Joshua Zimmberberg
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1855
| | - Bright Obeng
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - Julie Gosse
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - Samuel T. Hess
- Department of Physics and Astronomy, University of Maine, Orono, ME 04469-5709
- corresponding author: ; phone 207 581-1036; fax 207 581-3410
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4
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Murakami T, Ono A. Roles of Virion-Incorporated CD162 (PSGL-1), CD43, and CD44 in HIV-1 Infection of T Cells. Viruses 2021; 13:v13101935. [PMID: 34696365 PMCID: PMC8541244 DOI: 10.3390/v13101935] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/18/2021] [Accepted: 09/22/2021] [Indexed: 11/16/2022] Open
Abstract
Nascent HIV-1 particles incorporate the viral envelope glycoprotein and multiple host transmembrane proteins during assembly at the plasma membrane. At least some of these host transmembrane proteins on the surface of virions are reported as pro-viral factors that enhance virus attachment to target cells or facilitate trans-infection of CD4+ T cells via interactions with non-T cells. In addition to the pro-viral factors, anti-viral transmembrane proteins are incorporated into progeny virions. These virion-incorporated transmembrane proteins inhibit HIV-1 entry at the point of attachment and fusion. In infected polarized CD4+ T cells, HIV-1 Gag localizes to a rear-end protrusion known as the uropod. Regardless of cell polarization, Gag colocalizes with and promotes the virion incorporation of a subset of uropod-directed host transmembrane proteins, including CD162, CD43, and CD44. Until recently, the functions of these virion-incorporated proteins had not been clear. Here, we review the recent findings about the roles played by virion-incorporated CD162, CD43, and CD44 in HIV-1 spread to CD4+ T cells.
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5
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Herrmann D, Zhou LW, Hanson HM, Willkomm NA, Mansky LM, Saad JS. Structural Insights into the Mechanism of Human T-cell Leukemia Virus Type 1 Gag Targeting to the Plasma Membrane for Assembly. J Mol Biol 2021; 433:167161. [PMID: 34298060 PMCID: PMC8453114 DOI: 10.1016/j.jmb.2021.167161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/10/2021] [Accepted: 07/12/2021] [Indexed: 01/10/2023]
Abstract
Retroviral Gag targeting to the plasma membrane (PM) for assembly is mediated by the N-terminal matrix (MA) domain. For many retroviruses, Gag-PM interaction is dependent on phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). However, it has been shown that for human T-cell leukemia virus type 1 (HTLV-1), Gag binding to membranes is less dependent on PI(4,5)P2 than HIV-1, suggesting that other factors may modulate Gag assembly. To elucidate the mechanism by which HTLV-1 Gag binds to the PM, we employed NMR techniques to determine the structure of unmyristoylated MA (myr(-)MA) and to characterize its interactions with lipids and liposomes. The MA structure consists of four α-helices and unstructured N- and C-termini. We show that myr(-)MA binds to PI(4,5)P2 via the polar head and that binding to inositol phosphates (IPs) is significantly enhanced by increasing the number of phosphate groups on the inositol ring, indicating that the MA-IP binding is governed by charge-charge interactions. The IP binding site was mapped to a well-defined basic patch formed by lysine and arginine residues. Using an NMR-based liposome binding assay, we show that PI(4,5)P2and phosphatidylserine enhance myr(-)MA binding in a synergistic fashion. Confocal microscopy data revealed formation of puncta on the PM of Gag expressing cells. However, G2A-Gag mutant, lacking myristoylation, is diffuse and cytoplasmic. These results suggest that although myr(-)MA binds to membranes, myristoylation appears to be key for formation of HTLV-1 Gag puncta on the PM. Altogether, these findings advance our understanding of a key mechanism in retroviral assembly.
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Affiliation(s)
- Dominik Herrmann
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lynne W Zhou
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Heather M Hanson
- Institute for Molecular Virology, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA
| | - Nora A Willkomm
- Institute for Molecular Virology, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA
| | - Jamil S Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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6
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Rendezvous at Plasma Membrane: Cellular Lipids and tRNA Set up Sites of HIV-1 Particle Assembly and Incorporation of Host Transmembrane Proteins. Viruses 2020; 12:v12080842. [PMID: 32752131 PMCID: PMC7472227 DOI: 10.3390/v12080842] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/20/2020] [Accepted: 07/24/2020] [Indexed: 12/28/2022] Open
Abstract
The HIV-1 structural polyprotein Gag drives the virus particle assembly specifically at the plasma membrane (PM). During this process, the nascent virion incorporates specific subsets of cellular lipids and host membrane proteins, in addition to viral glycoproteins and viral genomic RNA. Gag binding to the PM is regulated by cellular factors, including PM-specific phospholipid PI(4,5)P2 and tRNAs, both of which bind the highly basic region in the matrix domain of Gag. In this article, we review our current understanding of the roles played by cellular lipids and tRNAs in specific localization of HIV-1 Gag to the PM. Furthermore, we examine the effects of PM-bound Gag on the organization of the PM bilayer and discuss how the reorganization of the PM at the virus assembly site potentially contributes to the enrichment of host transmembrane proteins in the HIV-1 particle. Since some of these host transmembrane proteins alter release, attachment, or infectivity of the nascent virions, the mechanism of Gag targeting to the PM and the nature of virus assembly sites have major implications in virus spread.
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7
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Carravilla P, Nieva JL, Eggeling C. Fluorescence Microscopy of the HIV-1 Envelope. Viruses 2020; 12:E348. [PMID: 32245254 PMCID: PMC7150788 DOI: 10.3390/v12030348] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 12/18/2022] Open
Abstract
Human immunodeficiency virus (HIV) infection constitutes a major health and social issue worldwide. HIV infects cells by fusing its envelope with the target cell plasma membrane. This process is mediated by the viral Env glycoprotein and depends on the envelope lipid composition. Fluorescent microscopy has been employed to investigate the envelope properties, and the processes of viral assembly and fusion, but the application of this technique to the study of HIV is still limited by a number of factors, such as the small size of HIV virions or the difficulty to label the envelope components. Here, we review fluorescence imaging studies of the envelope lipids and proteins, focusing on labelling strategies and model systems.
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Affiliation(s)
- Pablo Carravilla
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany;
- Leibniz Institute of Photonic Technology, Albert Einstein Strasse 9, 07743 Jena, Germany
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain;
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, E-48940 Leioa, Spain
| | - José L. Nieva
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain;
- Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country, E-48940 Leioa, Spain
| | - Christian Eggeling
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany;
- Leibniz Institute of Photonic Technology, Albert Einstein Strasse 9, 07743 Jena, Germany
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford OX3 9DS, UK
- Jena Center for Soft Matter (JCSM), Friedrich-Schiller-University Jena, Philosophenweg 7, 07743 Jena, Germany
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8
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Favard C, Chojnacki J, Merida P, Yandrapalli N, Mak J, Eggeling C, Muriaux D. HIV-1 Gag specifically restricts PI(4,5)P2 and cholesterol mobility in living cells creating a nanodomain platform for virus assembly. SCIENCE ADVANCES 2019; 5:eaaw8651. [PMID: 31616784 PMCID: PMC6774721 DOI: 10.1126/sciadv.aaw8651] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 09/09/2019] [Indexed: 06/10/2023]
Abstract
HIV-1 Gag protein assembles at the plasma membrane of infected cells for viral particle formation. Gag targets lipids, mainly PI(4,5)P2, at the inner leaflet of this membrane. Here, we address the question whether Gag is able to trap specifically PI(4,5)P2 or other lipids during HIV-1 assembly in the host CD4+ T lymphocytes. Lipid dynamics within and away from HIV-1 assembly sites were determined using super-resolution microscopy coupled with scanning fluorescence correlation spectroscopy in living cells. Analysis of HIV-1-infected cells revealed that, upon assembly, HIV-1 is able to specifically trap PI(4,5)P2 and cholesterol, but not phosphatidylethanolamine or sphingomyelin. Furthermore, our data showed that Gag is the main driving force to restrict the mobility of PI(4,5)P2 and cholesterol at the cell plasma membrane. This is the first direct evidence highlighting that HIV-1 creates its own specific lipid environment by selectively recruiting PI(4,5)P2 and cholesterol as a membrane nanoplatform for virus assembly.
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Affiliation(s)
- C. Favard
- Montpellier Infectious Disease Research Institute, IRIM, CNRS–Université Montpellier, 1919, route de Mende, 34293 Montpellier Cedex, France
| | - J. Chojnacki
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
- IrsiCaixa AIDS Research Institute, University Hospital Germans Trias i Pujol, Ctra. de Canyet s/n, Badalona, 08916 Barcelona, Spain
| | - P. Merida
- Montpellier Infectious Disease Research Institute, IRIM, CNRS–Université Montpellier, 1919, route de Mende, 34293 Montpellier Cedex, France
| | - N. Yandrapalli
- Montpellier Infectious Disease Research Institute, IRIM, CNRS–Université Montpellier, 1919, route de Mende, 34293 Montpellier Cedex, France
| | - J. Mak
- Institute for Glycomics, Griffith University Gold Coast, Southport, QLD, Australia
| | - C. Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 4, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - D. Muriaux
- Montpellier Infectious Disease Research Institute, IRIM, CNRS–Université Montpellier, 1919, route de Mende, 34293 Montpellier Cedex, France
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9
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Xiong W, Tang TX, Littleton E, Karcini A, Lazar IM, Capelluto DGS. Preferential phosphatidylinositol 5-phosphate binding contributes to a destabilization of the VHS domain structure of Tom1. Sci Rep 2019; 9:10868. [PMID: 31350523 PMCID: PMC6659632 DOI: 10.1038/s41598-019-47386-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/16/2019] [Indexed: 12/21/2022] Open
Abstract
Tom1 transports endosomal ubiquitinated proteins that are targeted for degradation in the lysosomal pathway. Infection of eukaryotic cells by Shigella flexneri boosts oxygen consumption and promotes the synthesis of phosphatidylinositol-5-phosphate (PtdIns5P), which triggers Tom1 translocation to signaling endosomes. Removing Tom1 from its cargo trafficking function hinders protein degradation in the host and, simultaneously, enables bacterial survival. Tom1 preferentially binds PtdIns5P via its VHS domain, but the effects of a reducing environment as well as PtdIns5P on the domain structure and function are unknown. Thermal denaturation studies demonstrate that, under reducing conditions, the monomeric Tom1 VHS domain switches from a three-state to a two-state transition behavior. PtdIns5P reduced thermostability, interhelical contacts, and conformational compaction of Tom1 VHS, suggesting that the phosphoinositide destabilizes the protein domain. Destabilization of Tom1 VHS structure was also observed with other phospholipids. Isothermal calorimetry data analysis indicates that, unlike ubiquitin, Tom1 VHS endothermically binds to PtdIns5P through two noncooperative binding sites, with its acyl chains playing a relevant role in the interaction. Altogether, these findings provide mechanistic insights about the recognition of PtdIns5P by the VHS domain that may explain how Tom1, when in a different VHS domain conformational state, interacts with downstream effectors under S. flexneri infection.
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Affiliation(s)
- Wen Xiong
- Protein Signaling Domains Laboratory, Department of Biological Sciences, Fralin Life Sciences Institute, and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Tuo-Xian Tang
- Protein Signaling Domains Laboratory, Department of Biological Sciences, Fralin Life Sciences Institute, and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Evan Littleton
- Protein Signaling Domains Laboratory, Department of Biological Sciences, Fralin Life Sciences Institute, and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Arba Karcini
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Iulia M Lazar
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Daniel G S Capelluto
- Protein Signaling Domains Laboratory, Department of Biological Sciences, Fralin Life Sciences Institute, and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, 24061, United States.
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10
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Tran RJ, Lalonde MS, Sly KL, Conboy JC. Mechanistic Investigation of HIV-1 Gag Association with Lipid Membranes. J Phys Chem B 2019; 123:4673-4687. [PMID: 31084006 DOI: 10.1021/acs.jpcb.9b02655] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An extensive investigation into the initial association of HIV-1 Gag with lipid membranes was conducted with second harmonic generation. The roles of the lipid phase, phospholipid 1,2-dioleoyl- sn-glycero-3-phospho-(1-myo-inositol-4,5-bisphosphate) [PI(4,5)P2], the presence of the myristoyl group on Gag, the C-terminus of Gag, and the presence of transfer ribonucleic acid (tRNA) in Gag-membrane association were examined using the physiologically most relevant full-length Gag protein studied thus far. The tighter packing of a bilayer composed of gel-phase lipids was found to have a lower relative amount of membrane-bound Gag in comparison to its fluid-phase counterpart. Rather than driving membrane association of Gag, the presence of PI(4,5)P2 and the myristoyl group were found to anchor Gag at the membrane by decreasing the rate of desorption. Specifically, the interaction with PI(4,5)P2 allows Gag to overcome electrostatic repulsion with negatively charged lipids at the membrane surface. This behavior was verified by measuring the binding properties of Gag mutants in the matrix domain of Gag, which prevented anchoring to the membrane either by blocking interaction with PI(4,5)P2 or by preventing exposure of the myristoyl group. The presence of tRNA was found to inhibit Gag association with the membrane by specifically blocking the PI(4,5)P2 binding region, thereby preventing exposure of the myristoyl group and precluding subsequent anchoring of Gag to the membrane. While Gag likely samples all membranes, only the anchoring provided by the myristoyl group and PI(4,5)P2 allows Gag to accumulate at the membrane. These quantitative results on the kinetics and thermodynamics of Gag association with lipid membranes provide important new information about the mechanism of Gag-membrane association.
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Affiliation(s)
- Renee J Tran
- Department of Chemistry , University of Utah , 315 South 1400 East, Room 2020 , Salt Lake City , Utah 84112 , United States
| | - Matthew S Lalonde
- Department of Biochemistry , University of Utah , 15 North Medical Drive East, Room 4100 , Salt Lake City , Utah 84112 , United States
| | - Krystal L Sly
- Department of Chemistry , University of Utah , 315 South 1400 East, Room 2020 , Salt Lake City , Utah 84112 , United States
| | - John C Conboy
- Department of Chemistry , University of Utah , 315 South 1400 East, Room 2020 , Salt Lake City , Utah 84112 , United States
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11
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Barklis E, Staubus AO, Mack A, Harper L, Barklis RL, Alfadhli A. Lipid biosensor interactions with wild type and matrix deletion HIV-1 Gag proteins. Virology 2018; 518:264-271. [PMID: 29549788 DOI: 10.1016/j.virol.2018.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/03/2018] [Accepted: 03/06/2018] [Indexed: 11/19/2022]
Abstract
The matrix (MA) domain of the HIV-1 precursor Gag protein (PrGag) has been shown interact with the HIV-1 envelope (Env) protein, and to direct PrGag proteins to plasma membrane (PM) assembly sites by virtue of its affinity to phosphatidylinositol-4,5-bisphosphate (PI[4,5]P2). Unexpectedly, HIV-1 viruses with large MA deletions (ΔMA) have been shown to be conditionally infectious as long as they are matched with Env truncation mutant proteins or alternative viral glycoproteins. To characterize the interactions of wild type (WT) and ΔMA Gag proteins with PI(4,5)P2 and other acidic phospholipids, we have employed a set of lipid biosensors as probes. Our investigations showed marked differences in WT and ΔMA Gag colocalization with biosensors, effects on biosensor release, and association of biosensors with virus-like particles. These results demonstrate an alternative approach to the analysis of viral protein-lipid associations, and provide new data as to the lipid compositions of HIV-1 assembly sites.
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Affiliation(s)
- Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States.
| | - August O Staubus
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
| | - Andrew Mack
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
| | - Logan Harper
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
| | - Robin Lid Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
| | - Ayna Alfadhli
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97035, United States
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12
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Noncoding RNAs in Retrovirus Replication. RETROVIRUS-CELL INTERACTIONS 2018. [PMCID: PMC7173536 DOI: 10.1016/b978-0-12-811185-7.00012-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although a limited percentage of the genome produces proteins, approximately 90% is transcribed, indicating important roles for noncoding RNA (ncRNA). It is now known that these ncRNAs have a multitude of cellular functions ranging from the regulation of gene expression to roles as structural elements in ribonucleoprotein complexes. ncRNA is also represented at nearly every step of viral life cycles. This chapter will focus on ncRNAs of both host and viral origin and their roles in retroviral life cycles. Cellular ncRNA represents a significant portion of material packaged into retroviral virions and includes transfer RNAs, 7SL RNA, U RNA, and vault RNA. Initially thought to be random packaging events, these host RNAs are now proposed to contribute to viral assembly and infectivity. Within the cell, long ncRNA and endogenous retroviruses have been found to regulate aspects of the retroviral life cycle in diverse ways. Additionally, the HIV-1 transactivating response element RNA is thought to impact viral infection beyond the well-characterized role as a transcription activator. RNA interference, thought to be an early version of the innate immune response to viral infection, can still be observed in plants and invertebrates today. The ability of retroviral infection to manipulate the host RNAi pathway is described here. Finally, RNA-based therapies, including gene editing approaches, are being explored as antiretroviral treatments and are discussed.
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Kulkarni MM, Ratcliff AN, Bhat M, Alwarawrah Y, Hughes P, Arcos J, Loiselle D, Torrelles JB, Funderburg NT, Haystead TA, Kwiek JJ. Cellular fatty acid synthase is required for late stages of HIV-1 replication. Retrovirology 2017; 14:45. [PMID: 28962653 PMCID: PMC5622536 DOI: 10.1186/s12977-017-0368-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 09/14/2017] [Indexed: 11/21/2022] Open
Abstract
Background
Like all viruses, HIV-1 relies on host systems to replicate. The human purinome consists of approximately two thousand proteins that bind and use purines such as ATP, NADH, and NADPH. By virtue of their purine binding pockets, purinome proteins are highly druggable, and many existing drugs target purine-using enzymes. Leveraging a protein affinity media that uses the purine-binding pocket to capture the entire purinome, we sought to define purine-binding proteins regulated by HIV-1 infection. Results Using purinome capture media, we observed that HIV-1 infection increases intracellular levels of fatty acid synthase (FASN), a NADPH-using enzyme critical to the synthesis of de novo fatty acids. siRNA mediated knockdown of FASN reduced HIV-1 particle production by 80%, and treatment of tissue culture cells or primary PBMCs with Fasnall, a newly described selective FASN inhibitor, reduced HIV-1 virion production by 90% (EC50 = 213 nM). Despite the requirement of FASN for nascent virion production, FASN activity was not required for intracellular Gag protein production, indicating that FASN dependent de novo fatty acid biosynthesis contributes to a late step of HIV-1 replication. Conclusions Here we show that HIV-1 replication both increases FASN levels and requires host FASN activity. We also report that Fasnall, a novel FASN inhibitor that demonstrates anti-tumor activity in vivo, is a potent and efficacious antiviral, blocking HIV-1 replication in both tissue culture and primary cell models of HIV-1 replication. In adults, most fatty acids are obtained exogenously from the diet, thus making FASN a plausible candidate for pharmacological intervention. In conclusion, we hypothesize that FASN is a novel host dependency factor and that inhibition of FASN activity has the potential to be exploited as an antiretroviral strategy.
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Affiliation(s)
- Manjusha M Kulkarni
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, Columbus, OH, USA
| | - Annette N Ratcliff
- Department of Microbiology, Center for Retrovirus Research, The Ohio State University, 476 Biological Sciences Building, 484 W. 12th Avenue, Columbus, OH, 43210, USA.,Promega Corporation, 2800 Woods Hollow Rd, Madison, WI, 53711-5399, USA
| | - Menakshi Bhat
- Department of Microbiology, Center for Retrovirus Research, The Ohio State University, 476 Biological Sciences Building, 484 W. 12th Avenue, Columbus, OH, 43210, USA
| | - Yazan Alwarawrah
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, C118 LSRC, Box 3813, Durham, NC, 27710, USA
| | - Philip Hughes
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, C118 LSRC, Box 3813, Durham, NC, 27710, USA
| | - Jesus Arcos
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, Columbus, OH, USA
| | - David Loiselle
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, C118 LSRC, Box 3813, Durham, NC, 27710, USA
| | - Jordi B Torrelles
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, The Ohio State University, Columbus, OH, USA.,Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Nicholas T Funderburg
- Division of Medical Laboratory Science, School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH, USA
| | - Timothy A Haystead
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, C118 LSRC, Box 3813, Durham, NC, 27710, USA.
| | - Jesse J Kwiek
- Department of Microbiology, Center for Retrovirus Research, The Ohio State University, 476 Biological Sciences Building, 484 W. 12th Avenue, Columbus, OH, 43210, USA.
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14
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Kim SO, Jackman JA, Elazar M, Cho SJ, Glenn JS, Cho NJ. Quantitative Evaluation of Viral Protein Binding to Phosphoinositide Receptors and Pharmacological Inhibition. Anal Chem 2017; 89:9742-9750. [PMID: 28809547 PMCID: PMC5724528 DOI: 10.1021/acs.analchem.7b01568] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
There is significant interest in developing analytical methods to characterize molecular recognition events between proteins and phosphoinositides, which are a medically important class of carbohydrate-functionalized lipids. Within this scope, one area of high priority involves quantitatively evaluating drug candidates that pharmacologically inhibit protein-phosphoinositide interactions. As full-length proteins are often difficult to produce, establishing methods to study these interactions with shorter, bioactive peptides would be advantageous. Herein, we report an atomic force microscopy (AFM)-based force spectroscopic approach to detect the specific interaction between an amphipathic, α-helical (AH) peptide derived from the hepatitis C virus NS5A protein and its biological target, the phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] phosphoinositide receptor. After optimization of the peptide tethering strategy and measurement parameters, the binding specificity of AH peptide for PI(4,5)P2 receptors was comparatively evaluated across a panel of phosphoinositides and the influence of ionic strength on AH-PI(4,5)P2 binding strength was tested. Importantly, these capabilities were translated into the development of a novel experimental methodology to determine the inhibitory activity of a small-molecule drug candidate acting against the AH-PI(4,5)P2 interaction, and extracted kinetic parameters agree well with literature values obtained by conventional biochemical methods. Taken together, our findings provide a nanomechanical basis for explaining the high binding specificity of the NS5A AH to PI(4,5)P2 receptors, in turn establishing an analytical framework to study phosphoinositide-binding viral peptides and proteins as well as a broadly applicable approach to evaluate candidate inhibitors of protein-phosphoinositide interactions.
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Affiliation(s)
- Seong-Oh Kim
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Drive, 637553 Singapore
| | - Joshua A Jackman
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Drive, 637553 Singapore.,Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine , Stanford, California 94305, United States
| | - Menashe Elazar
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine , Stanford, California 94305, United States
| | - Sang-Joon Cho
- Advanced Institute of Convergence Technology, Seoul National University , Suwon 443-270, South Korea
| | - Jeffrey S Glenn
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine , Stanford, California 94305, United States.,Veterans Administration Medical Center , Palo Alto, California 94304, United States
| | - Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Drive, 637553 Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University , 62 Nanyang Drive, 637459 Singapore
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15
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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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16
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Todd GC, Duchon A, Inlora J, Olson ED, Musier-Forsyth K, Ono A. Inhibition of HIV-1 Gag-membrane interactions by specific RNAs. RNA (NEW YORK, N.Y.) 2017; 23:395-405. [PMID: 27932583 PMCID: PMC5311501 DOI: 10.1261/rna.058453.116] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 12/07/2016] [Indexed: 05/03/2023]
Abstract
HIV-1 particle assembly, which occurs at the plasma membrane (PM) of cells, is driven by the viral polyprotein Gag. Gag recognizes phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2], a PM-specific phospholipid, via the highly basic region (HBR) in its N-terminal matrix (MA) domain. The HBR is also known to bind to RNA. We have previously shown, using an in vitro liposome binding assay, that RNA inhibits Gag binding to membranes that lack PI(4,5)P2 If this RNA block is removed by RNase treatment, Gag can bind nonspecifically to other negatively charged membranes. In an effort to identify the RNA species that confer this inhibition of Gag membrane binding, we have tested the impact of purified RNAs on Gag interactions with negatively charged liposomes lacking PI(4,5)P2 We found that some tRNA species and RNAs containing stem-loop 1 of the psi region in the 5' untranslated region of the HIV-1 genome impose inhibition of Gag binding to membranes lacking PI(4,5)P2 In contrast, a specific subset of tRNAs, as well as an RNA sequence previously selected in vitro for MA binding, failed to suppress Gag-membrane interactions. Furthermore, switching the identity of charged residues in the HBR did not diminish the susceptibility of Gag-liposome binding for each of the RNAs tested, while deletion of most of the NC domain abrogates the inhibition of membrane binding mediated by the RNAs that are inhibitory to WT Gag-liposome binding. These results support a model in which NC facilitates binding of RNA to MA and thereby promotes RNA-based inhibition of Gag-membrane binding.
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MESH Headings
- Aptamers, Nucleotide/chemical synthesis
- Aptamers, Nucleotide/pharmacology
- Base Pairing
- Base Sequence
- Binding Sites
- Cell Membrane/chemistry
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Cloning, Molecular
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression
- HIV-1/chemistry
- Humans
- Liposomes/antagonists & inhibitors
- Liposomes/chemistry
- Nucleic Acid Conformation
- Phosphatidylinositol 4,5-Diphosphate/chemistry
- Phosphatidylinositol 4,5-Diphosphate/deficiency
- Protein Binding/drug effects
- RNA, Transfer/chemistry
- RNA, Transfer/pharmacology
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Saccharomyces cerevisiae/chemistry
- Static Electricity
- gag Gene Products, Human Immunodeficiency Virus/antagonists & inhibitors
- gag Gene Products, Human Immunodeficiency Virus/chemistry
- gag Gene Products, Human Immunodeficiency Virus/genetics
- gag Gene Products, Human Immunodeficiency Virus/metabolism
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Affiliation(s)
- Gabrielle C Todd
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Alice Duchon
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Jingga Inlora
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Erik D Olson
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, and Center for Retrovirus Research, The Ohio State University, Columbus, Ohio 43210, USA
| | - Akira Ono
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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17
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Effects of Membrane Charge and Order on Membrane Binding of the Retroviral Structural Protein Gag. J Virol 2016; 90:9518-32. [PMID: 27512076 DOI: 10.1128/jvi.01102-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/05/2016] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED The retroviral structural protein Gag binds to the inner leaflet of the plasma membrane (PM), and many cellular proteins do so as well. We used Rous sarcoma virus (RSV) Gag together with membrane sensors to study the principles governing peripheral protein membrane binding, including electrostatics, specific recognition of phospholipid headgroups, sensitivity to phospholipid acyl chain compositions, preference for membrane order, and protein multimerization. We used an in vitro liposome-pelleting assay to test protein membrane binding properties of Gag, the well-characterized MARCKS peptide, a series of fluorescent electrostatic sensor proteins (mNG-KRn), and the specific phosphatidylserine (PS) binding protein Evectin2. RSV Gag and mNG-KRn bound well to membranes with saturated and unsaturated acyl chains, whereas the MARCKS peptide and Evectin2 preferentially bound to membranes with unsaturated acyl chains. To further discriminate whether the primary driving force for Gag membrane binding is electrostatic interactions or preference for membrane order, we measured protein binding to giant unilamellar vesicles (GUVs) containing the same PS concentration in both disordered (Ld) and ordered (Lo) phases. RSV Gag and mNG-KRn membrane association followed membrane charge, independent of membrane order. Consistent with pelleting data, the MARCKS peptide showed preference for the Ld domain. Surprisingly, the PS sensor Evectin2 bound to the PS-rich Ld domain with 10-fold greater affinity than to the PS-rich Lo domain. In summary, we found that RSV Gag shows no preference for membrane order, while proteins with reported membrane-penetrating domains show preference for disordered membranes. IMPORTANCE Retroviral particles assemble on the PM and bud from infected cells. Our understanding of how Gag interacts with the PM and how different membrane properties contribute to overall Gag assembly is incomplete. This study examined how membrane charge and membrane order influence Gag membrane association. Consistent with previous work on RSV Gag, we report here that electrostatic interactions provide the primary driving force for RSV Gag membrane association. Using phase-separated GUVs with known lipid composition of the Ld and Lo phases, we demonstrate for the first time that RSV Gag is sensitive to membrane charge but not membrane order. In contrast, the cellular protein domain MARCKS and the PS sensor Evectin2 show preference for disordered membranes. We also demonstrate how to define GUV phase composition, which could serve as a tool in future studies of protein membrane interactions.
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18
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Olety B, Veatch SL, Ono A. Visualization of HIV-1 Gag Binding to Giant Unilamellar Vesicle (GUV) Membranes. J Vis Exp 2016. [PMID: 27500610 DOI: 10.3791/54293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The structural protein of HIV-1, Pr55(Gag) (or Gag), binds to the plasma membrane in cells during the virus assembly process. Membrane binding of Gag is an essential step for virus particle formation, since a defect in Gag membrane binding results in severe impairment of viral particle production. To gain mechanistic details of Gag-lipid membrane interactions, in vitro methods based on NMR, protein footprinting, surface plasmon resonance, liposome flotation centrifugation, or fluorescence lipid bead binding have been developed thus far. However, each of these in vitro methods has its limitations. To overcome some of these limitations and provide a complementary approach to the previously established methods, we developed an in vitro assay in which interactions between HIV-1 Gag and lipid membranes take place in a "cell-like" environment. In this assay, Gag binding to lipid membranes is visually analyzed using YFP-tagged Gag synthesized in a wheat germ-based in vitro translation system and GUVs prepared by an electroformation technique. Here we describe the background and the protocols to obtain myristoylated full-length Gag proteins and GUV membranes necessary for the assay and to detect Gag-GUV binding by microscopy.
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Affiliation(s)
- Balaji Olety
- Department of Microbiology and Immunology, University of Michigan Medical School
| | | | - Akira Ono
- Department of Microbiology and Immunology, University of Michigan Medical School;
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19
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Nkwe DO, Pelchen-Matthews A, Burden JJ, Collinson LM, Marsh M. The intracellular plasma membrane-connected compartment in the assembly of HIV-1 in human macrophages. BMC Biol 2016; 14:50. [PMID: 27338237 PMCID: PMC4919869 DOI: 10.1186/s12915-016-0272-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/09/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In HIV-infected macrophages, newly formed progeny virus particles accumulate in intracellular plasma membrane-connected compartments (IPMCs). Although the virus is usually seen in these compartments, it is unclear whether HIV assembly is specifically targeted to IPMCs or whether some viruses may also form at the cell surface but are not detected, as particles budding from the latter site will be released into the medium. RESULTS To investigate the fidelity of HIV-1 targeting to IPMCs compared to the cell surface directly, we generated mutants defective in recruitment of the Endosomal Sorting Complexes Required for Transport (ESCRT) proteins required for virus scission. For mutants unable to bind the ESCRT-I component Tsg101, HIV release was inhibited and light and electron microscopy revealed that budding was arrested. When expressed in human monocyte-derived macrophages (MDM), these mutants formed budding-arrested, immature particles at their assembly sites, allowing us to capture virtually all of the virus budding events. A detailed morphological analysis of the distribution of the arrested viruses by immunofluorescence staining and confocal microscopy, and by electron microscopy, demonstrated that HIV assembly in MDMs is targeted primarily to IPMCs, with fewer than 5 % of budding events seen at the cell surface. Morphometric analysis of the relative membrane areas at the cell surface and IPMCs confirmed a large enrichment of virus assembly events in IPMCs. Serial block-face scanning electron microscopy of macrophages infected with a budding-defective HIV mutant revealed high-resolution 3D views of the complex organisation of IPMCs, with in excess of 15,000 associated HIV budding sites, and multiple connections between IPMCs and the cell surface. CONCLUSIONS Using detailed quantitative analysis, we demonstrate that HIV assembly in MDMs is specifically targeted to IPMCs. Furthermore, 3D analysis shows, for the first time, the detailed ultrastructure of an IPMC within a large cell volume, at a resolution that allowed identification of individual virus assembly events, and potential portals through which virus may be released during cell-cell transfer. These studies provide new insights to the organisation of the HIV assembly compartments in macrophages, and show how HIV particles accumulating in these protected sites may function as a virus reservoir.
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Affiliation(s)
- David O. Nkwe
- />MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT UK
- />Present Address: Department of Biology and Biotechnological Sciences, College of Science, Botswana International University of Science and Technology, Private Bag 16, Palapye, Botswana
| | - Annegret Pelchen-Matthews
- />MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT UK
| | - Jemima J. Burden
- />MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT UK
| | - Lucy M. Collinson
- />The Francis Crick Institute, Lincoln’s Inn Fields Laboratories, 44 Lincoln’s Inn Fields, London, WC2A 3LY UK
| | - Mark Marsh
- />MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT UK
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20
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Membrane Binding of HIV-1 Matrix Protein: Dependence on Bilayer Composition and Protein Lipidation. J Virol 2016; 90:4544-4555. [PMID: 26912608 DOI: 10.1128/jvi.02820-15] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/15/2016] [Indexed: 01/10/2023] Open
Abstract
UNLABELLED By assembling in a protein lattice on the host's plasma membrane, the retroviral Gag polyprotein triggers formation of the viral protein/membrane shell. The MA domain of Gag employs multiple signals--electrostatic, hydrophobic, and lipid-specific-to bring the protein to the plasma membrane, thereby complementing protein-protein interactions, located in full-length Gag, in lattice formation. We report the interaction of myristoylated and unmyristoylated HIV-1 Gag MA domains with bilayers composed of purified lipid components to dissect these complex membrane signals and quantify their contributions to the overall interaction. Surface plasmon resonance on well-defined planar membrane models is used to quantify binding affinities and amounts of protein and yields free binding energy contributions, ΔG, of the various signals. Charge-charge interactions in the absence of the phosphatidylinositide PI(4,5)P2 attract the protein to acidic membrane surfaces, and myristoylation increases the affinity by a factor of 10; thus, our data do not provide evidence for a PI(4,5)P2 trigger of myristate exposure. Lipid-specific interactions with PI(4,5)P2, the major signal lipid in the inner plasma membrane, increase membrane attraction at a level similar to that of protein lipidation. While cholesterol does not directly engage in interactions, it augments protein affinity strongly by facilitating efficient myristate insertion and PI(4,5)P2 binding. We thus observe that the isolated MA protein, in the absence of protein-protein interaction conferred by the full-length Gag, binds the membrane with submicromolar affinities. IMPORTANCE Like other retroviral species, the Gag polyprotein of HIV-1 contains three major domains: the N-terminal, myristoylated MA domain that targets the protein to the plasma membrane of the host; a central capsid-forming domain; and the C-terminal, genome-binding nucleocapsid domain. These domains act in concert to condense Gag into a membrane-bounded protein lattice that recruits genomic RNA into the virus and forms the shell of a budding immature viral capsid. In binding studies of HIV-1 Gag MA to model membranes with well-controlled lipid composition, we dissect the multiple interactions of the MA domain with its target membrane. This results in a detailed understanding of the thermodynamic aspects that determine membrane association, preferential lipid recruitment to the viral shell, and those aspects of Gag assembly into the membrane-bound protein lattice that are determined by MA.
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21
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Mercredi PY, Bucca N, Loeliger B, Gaines CR, Mehta M, Bhargava P, Tedbury PR, Charlier L, Floquet N, Muriaux D, Favard C, Sanders CR, Freed EO, Marchant J, Summers MF. Structural and Molecular Determinants of Membrane Binding by the HIV-1 Matrix Protein. J Mol Biol 2016; 428:1637-55. [PMID: 26992353 DOI: 10.1016/j.jmb.2016.03.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
Abstract
Assembly of HIV-1 particles is initiated by the trafficking of viral Gag polyproteins from the cytoplasm to the plasma membrane, where they co-localize and bud to form immature particles. Membrane targeting is mediated by the N-terminally myristoylated matrix (MA) domain of Gag and is dependent on the plasma membrane marker phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. Recent studies revealed that PI(4,5)P2 molecules containing truncated acyl chains [tr-PI(4,5)P2] are capable of binding MA in an "extended lipid" conformation and promoting myristoyl exposure. Here we report that tr-PI(4,5)P2 molecules also readily bind to non-membrane proteins, including HIV-1 capsid, which prompted us to re-examine MA-PI(4,5)P2 interactions using native lipids and membrane mimetic liposomes and bicelles. Liposome binding trends observed using a recently developed NMR approach paralleled results of flotation assays, although the affinities measured under the equilibrium conditions of NMR experiments were significantly higher. Native PI(4,5)P2 enhanced MA binding to liposomes designed to mimic non-raft-like regions of the membrane, suggesting the possibility that binding of the protein to disordered domains may precede Gag association with, or nucleation of, rafts. Studies with bicelles revealed a subset of surface and myr-associated MA residues that are sensitive to native PI(4,5)P2, but cleft residues that interact with the 2'-acyl chains of tr-PI(4,5)P2 molecules in aqueous solution were insensitive to native PI(4,5)P2 in bicelles. Our findings call to question extended-lipid MA:membrane binding models, and instead support a model put forward from coarse-grained simulations indicating that binding is mediated predominantly by dynamic, electrostatic interactions between conserved basic residues of MA and multiple PI(4,5)P2 and phosphatidylserine molecules.
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Affiliation(s)
- Peter Y Mercredi
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Nadine Bucca
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Burk Loeliger
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Christy R Gaines
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Mansi Mehta
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Pallavi Bhargava
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Philip R Tedbury
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, National Cancer Institute at Fredrick, Fredrick, MD 21702-1201, USA
| | - Landry Charlier
- Institut des Biomolécules Max Mousseron, CNRS UMR5247, Université Montpellier, Faculté de Pharmacie, Montpellier Cedex 05, France
| | - Nicolas Floquet
- Institut des Biomolécules Max Mousseron, CNRS UMR5247, Université Montpellier, Faculté de Pharmacie, Montpellier Cedex 05, France
| | - Delphine Muriaux
- Centre d'études d'agents Pathogénes et Biotechnologies pour la Santé CNRS-UMR 5236, Université Montpellier, Montpellier Cedex 5, France
| | - Cyril Favard
- Centre d'études d'agents Pathogénes et Biotechnologies pour la Santé CNRS-UMR 5236, Université Montpellier, Montpellier Cedex 5, France
| | - Charles R Sanders
- Department of Biochemistry, Center for Structural Biology, and Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, TN 37240-7917, USA
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, National Cancer Institute at Fredrick, Fredrick, MD 21702-1201, USA.
| | - Jan Marchant
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
| | - Michael F Summers
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA.
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