1
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Zeiger M, Pires M, Didier P, Vauchelles R, Mély Y, Boutant E, Real E. HIV-1 Gag Compact form Stabilized by Intramolecular Interactions is Crucial for Infectious Particle Production. J Mol Biol 2024; 436:168639. [PMID: 38838849 DOI: 10.1016/j.jmb.2024.168639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/29/2024] [Accepted: 05/30/2024] [Indexed: 06/07/2024]
Abstract
HIV-1 Gag polyprotein plays a pivotal role in assembly and budding of new particles, by specifically packaging two copies of viral gRNA in the host cell cytoplasm and selecting the cell plasma membrane for budding. Both gRNA and membrane selections are thought to be mediated by the compact form of Gag. This compact form binds to gRNA through both its matrix (MA) and nucleocapsid (NC) domains in the cytoplasm. At the plasma membrane, the membrane competes with gRNA for Gag binding, resulting in a transition to the extended form of Gag found in immature particles with MA bound to membrane lipids and NC to gRNA. The Gag compact form was previously evidenced in vitro. Here, we demonstrated the compact form of Gag in cells by confocal microscopy, using a bimolecular fluorescence complementation approach with a split-GFP bipartite system. Using wild-type Gag and Gag mutants, we showed that the compact form is highly dependent on the binding of MA and NC domains to RNA, as well as on interactions between MA and CA domains. In contrast, Gag multimerization appears to be less critical for the accumulation of the compact form. Finally, mutations altering the formation of Gag compact form led to a strong reduction in viral particle production and infectivity, revealing its key role in the production of infectious viral particles.
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Affiliation(s)
- Manon Zeiger
- UMR 7021, CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Manuel Pires
- UMR 7021, CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Pascal Didier
- UMR 7021, CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Romain Vauchelles
- UMR 7021, CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France
| | - Yves Mély
- UMR 7021, CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France.
| | - Emmanuel Boutant
- UMR 7021, CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France.
| | - Eléonore Real
- UMR 7021, CNRS, Laboratoire de Bioimagerie et Pathologies - LBP, Université de Strasbourg, Faculté de Pharmacie, Illkirch, France.
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2
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Častorálová M, Sýs J, Prchal J, Pavlů A, Prokopová L, Briki Z, Hubálek M, Ruml T. A myristoyl switch at the plasma membrane triggers cleavage and oligomerization of Mason-Pfizer monkey virus matrix protein. eLife 2024; 13:e93489. [PMID: 38517277 PMCID: PMC11014724 DOI: 10.7554/elife.93489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 03/10/2024] [Indexed: 03/23/2024] Open
Abstract
For most retroviruses, including HIV, association with the plasma membrane (PM) promotes the assembly of immature particles, which occurs simultaneously with budding and maturation. In these viruses, maturation is initiated by oligomerization of polyprotein precursors. In contrast, several retroviruses, such as Mason-Pfizer monkey virus (M-PMV), assemble in the cytoplasm into immature particles that are transported across the PM. Therefore, protease activation and specific cleavage must not occur until the pre-assembled particle interacts with the PM. This interaction is triggered by a bipartite signal consisting of a cluster of basic residues in the matrix (MA) domain of Gag polyprotein and a myristoyl moiety N-terminally attached to MA. Here, we provide evidence that myristoyl exposure from the MA core and its insertion into the PM occurs in M-PMV. By a combination of experimental methods, we show that this results in a structural change at the C-terminus of MA allowing efficient cleavage of MA from the downstream region of Gag. This suggests that, in addition to the known effect of the myristoyl switch of HIV-1 MA on the multimerization state of Gag and particle assembly, the myristoyl switch may have a regulatory role in initiating sequential cleavage of M-PMV Gag in immature particles.
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Affiliation(s)
- Markéta Častorálová
- Department of Biochemistry and Microbiology, University of Chemistry and TechnologyPragueCzech Republic
| | - Jakub Sýs
- Department of Biochemistry and Microbiology, University of Chemistry and TechnologyPragueCzech Republic
- Institute of Organic Chemistry and Biochemistry of Czech Academy of SciencePragueCzech Republic
| | - Jan Prchal
- Department of Biochemistry and Microbiology, University of Chemistry and TechnologyPragueCzech Republic
| | - Anna Pavlů
- Department of Biochemistry and Microbiology, University of Chemistry and TechnologyPragueCzech Republic
| | - Lucie Prokopová
- Department of Biochemistry and Microbiology, University of Chemistry and TechnologyPragueCzech Republic
| | - Zina Briki
- Department of Biochemistry and Microbiology, University of Chemistry and TechnologyPragueCzech Republic
| | - Martin Hubálek
- Institute of Organic Chemistry and Biochemistry of Czech Academy of SciencePragueCzech Republic
| | - Tomas Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and TechnologyPragueCzech Republic
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3
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Banerjee P, Monje-Galvan V, Voth GA. Cooperative Membrane Binding of HIV-1 Matrix Proteins. J Phys Chem B 2024; 128:2595-2606. [PMID: 38477117 PMCID: PMC10962350 DOI: 10.1021/acs.jpcb.3c06222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 02/24/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024]
Abstract
The HIV-1 assembly process begins with a newly synthesized Gag polyprotein being targeted to the inner leaflet of the plasma membrane of the infected cells to form immature viral particles. Gag-membrane interactions are mediated through the myristoylated (Myr) N-terminal matrix (MA) domain of Gag, which eventually multimerize on the membrane to form trimers and higher order oligomers. The study of the structure and dynamics of peripheral membrane proteins like MA has been challenging for both experimental and computational studies due to the complex transient dynamics of protein-membrane interactions. Although the roles of anionic phospholipids (PIP2, PS) and the Myr group in the membrane targeting and stable membrane binding of MA are now well-established, the cooperative interactions between the MA monomers and MA-membrane remain elusive in the context of viral assembly and release. Our present study focuses on the membrane binding dynamics of a higher order oligomeric structure of MA protein (a dimer of trimers), which has not been explored before. Employing time-lagged independent component analysis (tICA) to our microsecond-long trajectories, we investigate conformational changes of the matrix protein induced by membrane binding. Interestingly, the Myr switch of an MA monomer correlates with the conformational switch of adjacent monomers in the same trimer. Together, our findings suggest complex protein dynamics during the formation of the immature HIV-1 lattice; while MA trimerization facilitates Myr insertion, MA trimer-trimer interactions in the immature lattice can hinder the same.
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Affiliation(s)
- Puja Banerjee
- Department of Chemistry,
Chicago Center for Theoretical Chemistry, Institute for Biophysical
Dynamics, and James Franck Institute, The
University of Chicago, Chicago, Illinois 60637, United States
| | | | - Gregory A. Voth
- Department of Chemistry,
Chicago Center for Theoretical Chemistry, Institute for Biophysical
Dynamics, and James Franck Institute, The
University of Chicago, Chicago, Illinois 60637, United States
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4
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Banerjee P, Qu K, Briggs JAG, Voth GA. Molecular dynamics simulations of HIV-1 matrix-membrane interactions at different stages of viral maturation. Biophys J 2024; 123:389-406. [PMID: 38196190 PMCID: PMC10870173 DOI: 10.1016/j.bpj.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 12/05/2023] [Accepted: 01/04/2024] [Indexed: 01/11/2024] Open
Abstract
Although the structural rearrangement of the membrane-bound matrix (MA) protein trimers upon HIV-1 maturation has been reported, the consequences of MA maturation on the MA-lipid interactions are not well understood. Long-timescale molecular dynamics simulations of the MA multimeric assemblies of immature and mature virus particles with our realistic asymmetric membrane model have explored MA-lipid interactions and lateral organization of lipids around MA complexes. The number of stable MA-phosphatidylserine and MA-phosphatidylinositol 4,5-bisphosphate (PIP2) interactions at the trimeric interface of the mature MA complex is observed to be greater compared to that of the immature MA complex. Our simulations identified an alternative PIP2-binding site in the immature MA complex where the multivalent headgroup of a PIP2 lipid with a greater negative charge binds to multiple basic amino acid residues such as ARG3 residues of both the MA monomers at the trimeric interface and highly basic region (HBR) residues (LYS29, LYS31) of one of the MA monomers. Our enhanced sampling simulations have explored the conformational space of phospholipids at different binding sites of the trimer-trimer interface of MA complexes that are not accessible by conventional unbiased molecular dynamics. Unlike the immature MA complex, the 2' acyl tail of two PIP2 lipids at the trimeric interface of the mature MA complex is observed to sample stable binding pockets of MA consisting of helix-4 residues. Together, our results provide molecular-level insights into the interactions of MA trimeric complexes with membrane and different lipid conformations at the specific binding sites of MA protein before and after viral maturation.
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Affiliation(s)
- Puja Banerjee
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois
| | - Kun Qu
- Infectious Diseases Translational Research Programme, Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - John A G Briggs
- Department of Cell and Virus Structure, Max Planck Institute of Biochemistry, Planegg, Germany
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois.
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5
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Banerjee P, Voth GA. Conformational transitions of the HIV-1 Gag polyprotein upon multimerization and gRNA binding. Biophys J 2024; 123:42-56. [PMID: 37978800 PMCID: PMC10808027 DOI: 10.1016/j.bpj.2023.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/25/2023] [Accepted: 11/16/2023] [Indexed: 11/19/2023] Open
Abstract
During the HIV-1 assembly process, the Gag polyprotein multimerizes at the producer cell plasma membrane, resulting in the formation of spherical immature virus particles. Gag-genomic RNA (gRNA) interactions play a crucial role in the multimerization process, which is yet to be fully understood. We performed large-scale all-atom molecular dynamics simulations of membrane-bound full-length Gag dimer, hexamer, and 18-mer. The inter-domain dynamic correlation of Gag, quantified by the heterogeneous elastic network model applied to the simulated trajectories, is observed to be altered by implicit gRNA binding, as well as the multimerization state of the Gag. The lateral dynamics of our simulated membrane-bound Gag proteins, with and without gRNA binding, agree with prior experimental data and help to validate our simulation models and methods. The gRNA binding is observed to affect mainly the SP1 domain of the 18-mer and the matrix-capsid linker domain of the hexamer. In the absence of gRNA binding, the independent dynamical motion of the nucleocapsid domain results in a collapsed state of the dimeric Gag. Unlike stable SP1 helices in the six-helix bundle, without IP6 binding, the SP1 domain undergoes a spontaneous helix-to-coil transition in the dimeric Gag. Together, our findings reveal conformational switches of Gag at different stages of the multimerization process and predict that the gRNA binding reinforces an efficient binding surface of Gag for multimerization, and also regulates the dynamic organization of the local membrane region itself.
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Affiliation(s)
- Puja Banerjee
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Franck Institute, The University of Chicago, Chicago, Illinois.
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6
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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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7
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Zhang R, Pan S, Zheng S, Liao Q, Jiang Z, Wang D, Li X, Hu A, Li X, Zhu Y, Shen X, Lei J, Zhong S, Zhang X, Huang L, Wang X, Huang L, Shen L, Song BL, Zhao JW, Wang Z, Yang B, Guo X. Lipid-anchored proteasomes control membrane protein homeostasis. SCIENCE ADVANCES 2023; 9:eadj4605. [PMID: 38019907 PMCID: PMC10686573 DOI: 10.1126/sciadv.adj4605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023]
Abstract
Protein degradation in eukaryotic cells is mainly carried out by the 26S proteasome, a macromolecular complex not only present in the cytosol and nucleus but also associated with various membranes. How proteasomes are anchored to the membrane and the biological meaning thereof have been largely unknown in higher organisms. Here, we show that N-myristoylation of the Rpt2 subunit is a general mechanism for proteasome-membrane interaction. Loss of this modification in the Rpt2-G2A mutant cells leads to profound changes in the membrane-associated proteome, perturbs the endomembrane system, and undermines critical cellular processes such as cell adhesion, endoplasmic reticulum-associated degradation and membrane protein trafficking. Rpt2G2A/G2A homozygous mutation is embryonic lethal in mice and is sufficient to abolish tumor growth in a nude mice xenograft model. These findings have defined an evolutionarily conserved mechanism for maintaining membrane protein homeostasis and underscored the significance of compartmentalized protein degradation by myristoyl-anchored proteasomes in health and disease.
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Affiliation(s)
- Ruizhu Zhang
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Shuxian Pan
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Suya Zheng
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Qingqing Liao
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Zhaodi Jiang
- National Institute of Biological Sciences, Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100084, China
| | - Dixian Wang
- Department of Human Anatomy, Histology and Embryology, System Medicine Research Center, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Cryo-Electron Microscopy Center, Zhejiang University, Hangzhou 310058, China
| | - Xuemei Li
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Ao Hu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan 430072, China
| | - Xinran Li
- Zhejiang University-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311200, China
| | - Yezhang Zhu
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Xiaoqi Shen
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Jing Lei
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
- The MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Brain Science and Brain Medicine, Hangzhou 310058, China
| | - Siming Zhong
- Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining 314400, China
- Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH8 9YL, UK
| | - Xiaomei Zhang
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Lingyun Huang
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Xiaorong Wang
- Department of Physiology and Biophysics, University of California-Irvine, Irvine, CA 92697, USA
- Department of Developmental and Cell Biology, University of California-Irvine, Irvine, CA 92697, USA
| | - Lan Huang
- Department of Physiology and Biophysics, University of California-Irvine, Irvine, CA 92697, USA
- Department of Developmental and Cell Biology, University of California-Irvine, Irvine, CA 92697, USA
| | - Li Shen
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Bao-Liang Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Taikang Center for Life and Medical Sciences, Taikang Medical School, Wuhan University, Wuhan 430072, China
| | - Jing-Wei Zhao
- Department of Human Anatomy, Histology and Embryology, System Medicine Research Center, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Cryo-Electron Microscopy Center, Zhejiang University, Hangzhou 310058, China
| | - Zhiping Wang
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, China
- The MOE Frontier Science Center for Brain Research and Brain-Machine Integration, Zhejiang University School of Brain Science and Brain Medicine, Hangzhou 310058, China
| | - Bing Yang
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Xing Guo
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
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8
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Banerjee P, Monje-Galvan V, Voth GA. Cooperative Membrane Binding of HIV-1 Matrix Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.559012. [PMID: 37790356 PMCID: PMC10542177 DOI: 10.1101/2023.09.22.559012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The HIV-1 assembly process begins with a newly synthesized Gag polyprotein being targeted to the inner leaflet of the plasma membrane of the infected cells to form immature viral particles. Gag-membrane interactions are mediated through the myristoylated(Myr) N-terminal matrix (MA) domain of Gag which eventually multimerize on the membrane to form trimers and higher-order oligomers. The study of the structure and dynamics of peripheral membrane proteins like MA has been challenging for both experimental and computational studies due to the complex dynamics of protein-membrane interactions. Although the roles of anionic phospholipids (PIP2, PS) and the Myr group in the membrane targeting and stable membrane binding of MA are now well-established, the cooperative interactions between MA monomers and MA-membrane still remain elusive. Our present study focuses on the membrane binding dynamics of a higher-order oligomeric structure of MA protein (a dimer of trimers), which has not been explored before. Employing time-lagged independent component analysis (tICA) to our microsecond-long trajectories, we investigate conformational changes of the matrix protein induced by membrane binding. Interestingly, the Myr switch of a MA monomer correlates with the conformational switch of adjacent monomers in the same trimer. Together, our findings suggest that MA trimerization facilitates Myr insertion, but MA trimer-trimer interactions in the lattice of immature HIV-1 particles can hinder the same. Additionally, local lipid density patterns of different lipid species provide a signature of the initial stage of lipid-domain formation upon membrane binding of the protein complex. TOC
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9
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Banerjee P, Voth GA. Conformational transitions of the HIV-1 Gag polyprotein upon multimerization and gRNA binding. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.16.553549. [PMID: 37645781 PMCID: PMC10462060 DOI: 10.1101/2023.08.16.553549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
During the HIV-1 assembly process, the Gag polyprotein multimerizes at the producer cell plasma membrane, resulting in the formation of spherical immature virus particles. Gag-gRNA interactions play a crucial role in the multimerization process, which is yet to be fully understood. We have performed large-scale all-atom molecular dynamics simulations of membrane-bound full-length Gag dimer, hexamer, and 18-mer. The inter-domain dynamic correlation of Gag, quantified by the heterogeneous elastic network model (hENM) applied to the simulated trajectories, is observed to be altered by implicit gRNA binding, as well as the multimerization state of the Gag. The lateral dynamics of our simulated membrane-bound Gag proteins, with and without gRNA binding, agree with prior experimental data and help to validate our simulation models and methods. The gRNA binding is observed to impact mainly the SP1 domain of the 18-mer and the MA-CA linker domain of the hexamer. In the absence of gRNA binding, the independent dynamical motion of the NC domain results in a collapsed state of the dimeric Gag. Unlike stable SP1 helices in the six-helix bundle, without IP6 binding, the SP1 domain undergoes a spontaneous helix-to-coil transition in the dimeric Gag. Together, our findings reveal conformational switches of Gag at different stages of the multimerization process and predict that the gRNA binding reinforces an efficient binding surface of Gag for multimerization, as well as regulates the dynamic organization of the local membrane region itself. Significance Gag(Pr 55 Gag ) polyprotein orchestrates many essential events in HIV-1 assembly, including packaging of the genomic RNA (gRNA) in the immature virion. Although various experimental techniques, such as cryo-ET, X-ray, and NMR, have revealed structural properties of individual domains in the immature Gag clusters, structural and biophysical characterization of a full-length Gag molecule remains a challenge for existing experimental techniques. Using atomistic molecular dynamics simulations of the different model systems of Gag polyprotein, we present here a detailed structural characterization of Gag molecules in different multimerization states and interrogate the synergy between Gag-Gag, Gag-membrane, and Gag-gRNA interactions during the viral assembly process.
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10
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Yoo SW, Waheed AA, Deme P, Tohumeken S, Rais R, Smith MD, DeMarino C, Calabresi PA, Kashanchi F, Freed EO, Slusher BS, Haughey NJ. Inhibition of neutral sphingomyelinase 2 impairs HIV-1 envelope formation and substantially delays or eliminates viral rebound. Proc Natl Acad Sci U S A 2023; 120:e2219543120. [PMID: 37406092 PMCID: PMC10334757 DOI: 10.1073/pnas.2219543120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/03/2023] [Indexed: 07/07/2023] Open
Abstract
Although HIV-1 Gag is known to drive viral assembly and budding, the precise mechanisms by which the lipid composition of the plasma membrane is remodeled during assembly are incompletely understood. Here, we provide evidence that the sphingomyelin hydrolase neutral sphingomyelinase 2 (nSMase2) interacts with HIV-1 Gag and through the hydrolysis of sphingomyelin creates ceramide that is necessary for proper formation of the viral envelope and viral maturation. Inhibition or depletion of nSMase2 resulted in the production of noninfectious HIV-1 virions with incomplete Gag lattices lacking condensed conical cores. Inhibition of nSMase2 in HIV-1-infected humanized mouse models with a potent and selective inhibitor of nSMase2 termed PDDC [phenyl(R)-(1-(3-(3,4-dimethoxyphenyl)-2, 6-dimethylimidazo[1,2-b]pyridazin-8-yl) pyrrolidin-3-yl)-carbamate] produced a linear reduction in levels of HIV-1 in plasma. If undetectable plasma levels of HIV-1 were achieved with PDDC treatment, viral rebound did not occur for up to 4 wk when PDDC was discontinued. In vivo and tissue culture results suggest that PDDC selectively kills cells with actively replicating HIV-1. Collectively, this work demonstrates that nSMase2 is a critical regulator of HIV-1 replication and suggests that nSMase2 could be an important therapeutic target with the potential to kill HIV-1-infected cells.
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Affiliation(s)
- Seung-Wan Yoo
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Abdul A. Waheed
- Virus-Cell Interaction Section, HIV-1 Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD21702
| | - Pragney Deme
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Sehmus Tohumeken
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Rana Rais
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Matthew D. Smith
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Catherine DeMarino
- Laboratory of Molecular Virology, George Mason University, Manassas, VA20110
| | - Peter A. Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Fatah Kashanchi
- Laboratory of Molecular Virology, George Mason University, Manassas, VA20110
| | - Eric O. Freed
- Virus-Cell Interaction Section, HIV-1 Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD21702
| | - Barbara S. Slusher
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
- Johns Hopkins Drug Discovery, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21210
- Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21210
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD21224
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD21210
| | - Norman J. Haughey
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD21210
- Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21210
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11
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Socas L, Ambroggio E. HIV-1 Gag specificity for PIP2 is regulated by macromolecular electric properties of both protein and membrane local environments. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - BIOMEMBRANES 2023; 1865:184157. [PMID: 37028700 DOI: 10.1016/j.bbamem.2023.184157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/14/2023] [Accepted: 03/29/2023] [Indexed: 04/08/2023]
Abstract
HIV-1 assembly occurs at the plasma membrane, with the Gag polyprotein playing a crucial role. Gag association with the membrane is directed by the matrix domain (MA), which is myristoylated and has a highly basic region that interacts with anionic lipids. Several pieces of evidence suggest that the presence of phosphatidylinositol-(4,5)-bisphosphate (PIP2) highly influences this binding. Furthermore, MA also interacts with nucleic acids, which is proposed to be important for the specificity of GAG for PIP2-containing membranes. It is hypothesized that RNA has a chaperone function by interacting with the MA domain, preventing Gag from associating with unspecific lipid interfaces. Here, we study the interaction of MA with monolayer and bilayer membrane systems, focusing on the specificity for PIP2 and on the possible effects of a Gag N-terminal peptide on impairing the binding for either RNA or membrane. We found that RNA decreases the kinetics of the protein association with lipid monolayers but has no effect on the selectivity for PIP2. Interestingly, for bilayer systems, this selectivity increases in presence of both the peptide and RNA, even for highly negatively charged compositions, where MA alone does not discriminate between membranes with or without PIP2. Therefore, we propose that the specificity of MA for PIP2-containing membranes might be related to the electrostatic properties of both membrane and protein local environments, rather than a simple difference in molecular affinities. This scenario provides a new understanding of the regulation mechanism, with a macromolecular view, rather than considering molecular interactions within a ligand-receptor model.
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12
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Identification of New L-Heptanoylphosphatidyl Inositol Pentakisphosphate Derivatives Targeting the Interaction with HIV-1 Gag by Molecular Modelling Studies. Pharmaceuticals (Basel) 2022; 15:ph15101255. [PMID: 36297367 PMCID: PMC9610595 DOI: 10.3390/ph15101255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/29/2022] [Accepted: 10/08/2022] [Indexed: 11/16/2022] Open
Abstract
The HIV-1 Gag protein binds to the host cell membrane and assembles into immature particles. Then, in the course of immature virion budding, activated protease cleaves Gag into its main components: MA, CA, NC, and p6 proteins. The highly basic residues of MA predominantly interact with the acidic head of phosphatidyl-inositol-4,5-bisphosphate (PI(4,5)P2) inserted into the membrane. Our research group developed L-Heptanoylphosphatidyl Inositol Pentakisphosphate (L-HIPPO) and previously confirmed that this compound bound to the MA more strongly than PI(4,5)P2 and inositol hexakisphosphate (IP6) did. Therefore, herein we rationally designed eight new L-HIPPO derivatives based on the fact that the most changeable parts of L-HIPPO were two acyl chains. After that, we employed molecular docking for eight compounds via Maestro software using high-resolution crystal structures of MA in complex with IP6 (PDB IDs: 7E1I, 7E1J, and 7E1K), which were recently elucidated by our research group. The most promising docking scores were obtained with benzene-inserted compounds. Thus, we generated a library containing 213 new aromatic group-inserted L-HIPPO derivatives and performed the same molecular docking procedure. According to the results, we determined the nine new L-HIPPO derivatives most effectively binding to the MA with the most favorable scoring functions and pharmacokinetic properties for further exploration.
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13
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The HIV-1 Gag Protein Displays Extensive Functional and Structural Roles in Virus Replication and Infectivity. Int J Mol Sci 2022; 23:ijms23147569. [PMID: 35886917 PMCID: PMC9323242 DOI: 10.3390/ijms23147569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/15/2022] [Accepted: 06/19/2022] [Indexed: 01/10/2023] Open
Abstract
Once merely thought of as the protein responsible for the overall physical nature of the human immunodeficiency virus type 1 (HIV-1), the Gag polyprotein has since been elucidated to have several roles in viral replication and functionality. Over the years, extensive research into the polyproteins’ structure has revealed that Gag can mediate its own trafficking to the plasma membrane, it can interact with several host factors and can even aid in viral genome packaging. Not surprisingly, Gag has also been associated with HIV-1 drug resistance and even treatment failure. Therefore, this review provides an extensive overview of the structural and functional roles of the HIV-1 Gag domains in virion integrity, functionality and infectivity.
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14
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Atomic view of the HIV-1 matrix lattice; implications on virus assembly and envelope incorporation. Proc Natl Acad Sci U S A 2022; 119:e2200794119. [PMID: 35658080 PMCID: PMC9191676 DOI: 10.1073/pnas.2200794119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
SignificanceThe assembly of immature HIV-1 particles is initiated by targeting of the Gag polyproteins to the plasma membrane (PM). Gag binding to the PM is mediated by the N-terminally myristoylated matrix (myrMA) domain. Formation of a Gag lattice on the PM is obligatory for the assembly of immature HIV-1 and envelope (Env) incorporation. The structure of the myrMA lattice presented here provided insights on the molecular factors that stabilize the lattice and hence favor Env incorporation. Our data support a mechanism for Gag binding to the PM during the assembly of immature particles and upon maturation. These findings advance our understanding of a critical step in HIV-1 assembly.
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15
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Bou-Nader C, Zhang J. Rational engineering enables co-crystallization and structural determination of the HIV-1 matrix-tRNA complex. STAR Protoc 2022; 3:101056. [PMID: 35005638 PMCID: PMC8715211 DOI: 10.1016/j.xpro.2021.101056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Host tRNAs specifically interact with the matrix domain (MA) of HIV-1 major structural polyprotein, Gag, to control its membrane localization and virion assembly. In this protocol, we describe the purification and engineering of HIV-1 MA and tRNA, and the co-crystallization and structure determination of the complex using X-ray crystallography. Rational engineering of the tRNA surface created tRNA-tRNA packing contacts that drove the formation of diffraction-quality co-crystals. This protocol can be adapted to solve other ribonucleoprotein complex structures containing structured RNAs. For complete details on the use and execution of this protocol, please refer to Bou-Nader et al. (2021).
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Affiliation(s)
- Charles Bou-Nader
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
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16
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Sumner C, Ono A. Relationship between HIV-1 Gag Multimerization and Membrane Binding. Viruses 2022; 14:v14030622. [PMID: 35337029 PMCID: PMC8949992 DOI: 10.3390/v14030622] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/06/2022] [Accepted: 03/09/2022] [Indexed: 12/11/2022] Open
Abstract
HIV-1 viral particle assembly occurs specifically at the plasma membrane and is driven primarily by the viral polyprotein Gag. Selective association of Gag with the plasma membrane is a key step in the viral assembly pathway, which is traditionally attributed to the MA domain. MA regulates specific plasma membrane binding through two primary mechanisms including: (1) specific interaction of the MA highly basic region (HBR) with the plasma membrane phospholipid phosphatidylinositol (4,5) bisphosphate [PI(4,5)P2], and (2) tRNA binding to the MA HBR, which prevents Gag association with non-PI(4,5)P2 containing membranes. Gag multimerization, driven by both CA–CA inter-protein interactions and NC-RNA binding, also plays an essential role in viral particle assembly, mediating the establishment and growth of the immature Gag lattice on the plasma membrane. In addition to these functions, the multimerization of HIV-1 Gag has also been demonstrated to enhance its membrane binding activity through the MA domain. This review provides an overview of the mechanisms regulating Gag membrane binding through the MA domain and multimerization through the CA and NC domains, and examines how these two functions are intertwined, allowing for multimerization mediated enhancement of Gag membrane binding.
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17
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Lerner G, Weaver N, Anokhin B, Spearman P. Advances in HIV-1 Assembly. Viruses 2022; 14:v14030478. [PMID: 35336885 PMCID: PMC8952333 DOI: 10.3390/v14030478] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/10/2022] Open
Abstract
The assembly of HIV-1 particles is a concerted and dynamic process that takes place on the plasma membrane of infected cells. An abundance of recent discoveries has advanced our understanding of the complex sequence of events leading to HIV-1 particle assembly, budding, and release. Structural studies have illuminated key features of assembly and maturation, including the dramatic structural transition that occurs between the immature Gag lattice and the formation of the mature viral capsid core. The critical role of inositol hexakisphosphate (IP6) in the assembly of both the immature and mature Gag lattice has been elucidated. The structural basis for selective packaging of genomic RNA into virions has been revealed. This review will provide an overview of the HIV-1 assembly process, with a focus on recent advances in the field, and will point out areas where questions remain that can benefit from future investigation.
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18
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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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19
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Krebs AS, Mendonça LM, Zhang P. Structural Analysis of Retrovirus Assembly and Maturation. Viruses 2021; 14:54. [PMID: 35062258 PMCID: PMC8778513 DOI: 10.3390/v14010054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/17/2021] [Accepted: 12/21/2021] [Indexed: 12/30/2022] Open
Abstract
Retroviruses have a very complex and tightly controlled life cycle which has been studied intensely for decades. After a virus enters the cell, it reverse-transcribes its genome, which is then integrated into the host genome, and subsequently all structural and regulatory proteins are transcribed and translated. The proteins, along with the viral genome, assemble into a new virion, which buds off the host cell and matures into a newly infectious virion. If any one of these steps are faulty, the virus cannot produce infectious viral progeny. Recent advances in structural and molecular techniques have made it possible to better understand this class of viruses, including details about how they regulate and coordinate the different steps of the virus life cycle. In this review we summarize the molecular analysis of the assembly and maturation steps of the life cycle by providing an overview on structural and biochemical studies to understand these processes. We also outline the differences between various retrovirus families with regards to these processes.
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Affiliation(s)
- Anna-Sophia Krebs
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.-S.K.); (L.M.M.)
| | - Luiza M. Mendonça
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.-S.K.); (L.M.M.)
| | - Peijun Zhang
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.-S.K.); (L.M.M.)
- Electron Bio-Imaging Centre, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
- Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford OX3 7BN, UK
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20
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McFadden WM, Snyder AA, Kirby KA, Tedbury PR, Raj M, Wang Z, Sarafianos SG. Rotten to the core: antivirals targeting the HIV-1 capsid core. Retrovirology 2021; 18:41. [PMID: 34937567 PMCID: PMC8693499 DOI: 10.1186/s12977-021-00583-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/09/2021] [Indexed: 12/20/2022] Open
Abstract
The capsid core of HIV-1 is a large macromolecular assembly that surrounds the viral genome and is an essential component of the infectious virus. In addition to its multiple roles throughout the viral life cycle, the capsid interacts with multiple host factors. Owing to its indispensable nature, the HIV-1 capsid has been the target of numerous antiretrovirals, though most capsid-targeting molecules have not had clinical success until recently. Lenacapavir, a long-acting drug that targets the HIV-1 capsid, is currently undergoing phase 2/3 clinical trials, making it the most successful capsid inhibitor to-date. In this review, we detail the role of the HIV-1 capsid protein in the virus life cycle, categorize antiviral compounds based on their targeting of five sites within the HIV-1 capsid, and discuss their molecular interactions and mechanisms of action. The diverse range of inhibition mechanisms provides insight into possible new strategies for designing novel HIV-1 drugs and furthers our understanding of HIV-1 biology. ![]()
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Affiliation(s)
- William M McFadden
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Alexa A Snyder
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Karen A Kirby
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
| | - Philip R Tedbury
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA.,Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA
| | - Monika Raj
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | - Zhengqiang Wang
- Center for Drug Design, College of Pharmacy, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Stefan G Sarafianos
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA. .,Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA.
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21
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Ricaña CL, Dick RA. Inositol Phosphates and Retroviral Assembly: A Cellular Perspective. Viruses 2021; 13:v13122516. [PMID: 34960784 PMCID: PMC8703376 DOI: 10.3390/v13122516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/09/2021] [Accepted: 12/11/2021] [Indexed: 12/13/2022] Open
Abstract
Understanding the molecular mechanisms of retroviral assembly has been a decades-long endeavor. With the recent discovery of inositol hexakisphosphate (IP6) acting as an assembly co-factor for human immunodeficiency virus (HIV), great strides have been made in retroviral research. In this review, the enzymatic pathways to synthesize and metabolize inositol phosphates (IPs) relevant to retroviral assembly are discussed. The functions of these enzymes and IPs are outlined in the context of the cellular biology important for retroviruses. Lastly, the recent advances in understanding the role of IPs in retroviral biology are surveyed.
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22
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Long M, Toesca J, Guillon C. Review and Perspectives on the Structure-Function Relationships of the Gag Subunits of Feline Immunodeficiency Virus. Pathogens 2021; 10:pathogens10111502. [PMID: 34832657 PMCID: PMC8621984 DOI: 10.3390/pathogens10111502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 11/16/2022] Open
Abstract
The Gag polyprotein is implied in the budding as well as the establishment of the supramolecular architecture of infectious retroviral particles. It is also involved in the early phases of the replication of retroviruses by protecting and transporting the viral genome towards the nucleus of the infected cell until its integration in the host genome. Therefore, understanding the structure-function relationships of the Gag subunits is crucial as each of them can represent a therapeutic target. Though the field has been explored for some time in the area of Human Immunodeficiency Virus (HIV), it is only in the last decade that structural data on Feline Immunodeficiency Virus (FIV) Gag subunits have emerged. As FIV is an important veterinary issue, both in domestic cats and endangered feline species, such data are of prime importance for the development of anti-FIV molecules targeting Gag. This review will focus on the recent advances and perspectives on the structure-function relationships of each subunit of the FIV Gag polyprotein.
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Affiliation(s)
- Mathieu Long
- Retroviruses and Structural Biochemistry, Molecular Microbiology and Structural Biochemistry, CNRS, Univ Lyon, UMR5086, 69007 Lyon, France; (M.L.); (J.T.)
- Center for Molecular Protein Science, Department of Chemistry, Lund University, Lund, 221 00 Scania, Sweden
| | - Johan Toesca
- Retroviruses and Structural Biochemistry, Molecular Microbiology and Structural Biochemistry, CNRS, Univ Lyon, UMR5086, 69007 Lyon, France; (M.L.); (J.T.)
- Enveloped Viruses, Vectors and Immunotherapy, CIRI-Centre International de Recherche en Infectiologie, Univ Lyon, Université Claude Bernard Lyon 1, UMR5308, ENS Lyon, 69007 Lyon, France
| | - Christophe Guillon
- Retroviruses and Structural Biochemistry, Molecular Microbiology and Structural Biochemistry, CNRS, Univ Lyon, UMR5086, 69007 Lyon, France; (M.L.); (J.T.)
- Correspondence:
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23
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Interplay between Host tRNAs and HIV-1: A Structural Perspective. Viruses 2021; 13:v13091819. [PMID: 34578400 PMCID: PMC8473020 DOI: 10.3390/v13091819] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/06/2021] [Accepted: 09/09/2021] [Indexed: 12/23/2022] Open
Abstract
The cellular metabolism of host tRNAs and life cycle of HIV-1 cross paths at several key virus-host interfaces. Emerging data suggest a multi-faceted interplay between host tRNAs and HIV-1 that plays essential roles, both structural and regulatory, in viral genome replication, genome packaging, and virion biogenesis. HIV-1 not only hijacks host tRNAs and transforms them into obligatory reverse transcription primers but further commandeers tRNAs to regulate the localization of its major structural protein, Gag, via a specific interface. This review highlights recent advances in understanding tRNA-HIV-1 interactions, primarily from a structural perspective, which start to elucidate their underlying molecular mechanisms, intrinsic specificities, and biological significances. Such understanding may provide new avenues toward developing HIV/AIDS treatments and therapeutics including small molecules and RNA biologics that target these host-virus interfaces.
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24
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Bou-Nader C, Muecksch F, Brown JB, Gordon JM, York A, Peng C, Ghirlando R, Summers MF, Bieniasz PD, Zhang J. HIV-1 matrix-tRNA complex structure reveals basis for host control of Gag localization. Cell Host Microbe 2021; 29:1421-1436.e7. [PMID: 34384537 PMCID: PMC8650744 DOI: 10.1016/j.chom.2021.07.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/24/2021] [Accepted: 07/19/2021] [Indexed: 10/20/2022]
Abstract
The HIV-1 virion structural polyprotein, Gag, is directed to particle assembly sites at the plasma membrane by its N-terminal matrix (MA) domain. MA also binds to host tRNAs. To understand the molecular basis of MA-tRNA interaction and its potential function, we present a co-crystal structure of HIV-1 MA-tRNALys3 complex. The structure reveals a specialized group of MA basic and aromatic residues preconfigured to recognize the distinctive structure of the tRNA elbow. Mutational, cross-linking, fluorescence, and NMR analyses show that the crystallographically defined interface drives MA-tRNA binding in solution and living cells. The structure indicates that MA is unlikely to bind tRNA and membrane simultaneously. Accordingly, single-amino-acid substitutions that abolish MA-tRNA binding caused striking redistribution of Gag to the plasma membrane and reduced HIV-1 replication. Thus, HIV-1 exploits host tRNAs to occlude a membrane localization signal and control the subcellular distribution of its major structural protein.
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Affiliation(s)
- Charles Bou-Nader
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Frauke Muecksch
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Janae B Brown
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Jackson M Gordon
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Ashley York
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Chen Peng
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Michael F Summers
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, MD 21250, USA; Howard Hughes Medical Institute, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Paul D Bieniasz
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA.
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
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25
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Subtype Differences in the Interaction of HIV-1 Matrix with Calmodulin: Implications for Biological Functions. Biomolecules 2021; 11:biom11091294. [PMID: 34572507 PMCID: PMC8464830 DOI: 10.3390/biom11091294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/10/2021] [Accepted: 08/28/2021] [Indexed: 01/10/2023] Open
Abstract
The HIV-1 Gag polyprotein plays essential roles during the late stage of the HIV-1 replication cycle, and has recently been identified as a promising therapeutic target. The N-terminal portion of the HIV-1 Gag polyprotein encodes the myristoylated matrix (MA) protein, which functions in the trafficking of the structural proteins to the plasma membrane (PM) and facilitation of envelope incorporation into budding virus. Numerous host cell proteins interact with the MA portion of the Gag polyprotein during this process. One such factor is the ubiquitous calcium-binding protein calmodulin (CaM), which interacts preferentially with myristoylated proteins, thereby regulating cell physiology. The exact role of this interaction is poorly understood to date. Atomic resolution structures revealed the nature of the CaM-MA interaction for clade B isolates. In this study, we expanded our knowledge and characterized biophysically and computationally the CaM interaction with MA from other HIV-1 clades and discovered differences in the CaM recognition as compared to the prototypical clade B MA, with significant alterations in the interaction with the MA protein from clade C. Structural investigation and in silico mutational analysis revealed that HIV-1 MA protein from clade C, which is responsible for the majority of global HIV-1 infections, interacts with lower affinity and altered kinetics as compared to the canonical clade B. This finding may have implications for additional altered interaction networks as compared to the well-studied clade B. Our analysis highlights the importance of expanding investigations of virus-host cell factor interaction networks to other HIV-1 clades.
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Qu K, Ke Z, Zila V, Anders-Össwein M, Glass B, Mücksch F, Müller R, Schultz C, Müller B, Kräusslich HG, Briggs JAG. Maturation of the matrix and viral membrane of HIV-1. Science 2021; 373:700-704. [PMID: 34353956 DOI: 10.1126/science.abe6821] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 06/24/2021] [Indexed: 12/22/2022]
Abstract
Gag, the primary structural protein of HIV-1, is recruited to the plasma membrane for virus assembly by its matrix (MA) domain. Gag is subsequently cleaved into its component domains, causing structural maturation to repurpose the virion for cell entry. We determined the structure and arrangement of MA within immature and mature HIV-1 through cryo-electron tomography. We found that MA rearranges between two different hexameric lattices upon maturation. In mature HIV-1, a lipid extends out of the membrane to bind with a pocket in MA. Our data suggest that proteolytic maturation of HIV-1 not only assembles the viral capsid surrounding the genome but also repurposes the membrane-bound MA lattice for an entry or postentry function and results in the partial removal of up to 2500 lipids from the viral membrane.
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Affiliation(s)
- Kun Qu
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory and Universitätsklinikum Heidelberg, 69117 Heidelberg, Germany.,Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, UK.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Molecular Medicine Partnership Unit, European Molecular Biology Laboratory and Universitätsklinikum Heidelberg, 69117 Heidelberg, Germany
| | - Zunlong Ke
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany.,Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, UK
| | - Vojtech Zila
- Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, UK.,Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany
| | - Maria Anders-Össwein
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany
| | - Bärbel Glass
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany
| | - Frauke Mücksch
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany
| | - Rainer Müller
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory and Universitätsklinikum Heidelberg, 69117 Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Carsten Schultz
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory and Universitätsklinikum Heidelberg, 69117 Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239, USA
| | - Barbara Müller
- Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, UK.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, UK.,Molecular Medicine Partnership Unit, European Molecular Biology Laboratory and Universitätsklinikum Heidelberg, 69117 Heidelberg, Germany.,Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany.,German Center for Infection Research, Heidelberg, Germany
| | - John A G Briggs
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany. .,Molecular Medicine Partnership Unit, European Molecular Biology Laboratory and Universitätsklinikum Heidelberg, 69117 Heidelberg, Germany.,Structural Studies Division, Medical Research Council Laboratory of Molecular Biology, CB2 0QH Cambridge, UK.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Molecular Medicine Partnership Unit, European Molecular Biology Laboratory and Universitätsklinikum Heidelberg, 69117 Heidelberg, Germany
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27
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Welker L, Paillart JC, Bernacchi S. Importance of Viral Late Domains in Budding and Release of Enveloped RNA Viruses. Viruses 2021; 13:1559. [PMID: 34452424 PMCID: PMC8402826 DOI: 10.3390/v13081559] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 01/09/2023] Open
Abstract
Late assembly (L) domains are conserved sequences that are necessary for the late steps of viral replication, acting like cellular adaptors to engage the ESCRT membrane fission machinery that promote virion release. These short sequences, whose mutation or deletion produce the accumulation of immature virions at the plasma membrane, were firstly identified within retroviral Gag precursors, and in a further step, also in structural proteins of many other enveloped RNA viruses including arenaviruses, filoviruses, rhabdoviruses, reoviruses, and paramyxoviruses. Three classes of L domains have been identified thus far (PT/SAP, YPXnL/LXXLF, and PPxY), even if it has recently been suggested that other motifs could act as L domains. Here, we summarize the current state of knowledge of the different types of L domains and their cellular partners in the budding events of RNA viruses, with a particular focus on retroviruses.
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Affiliation(s)
| | | | - Serena Bernacchi
- Architecture et Réactivité de l’ARN, UPR 9002, IBMC, CNRS, Université de Strasbourg, F-67000 Strasbourg, France; (L.W.); (J.-C.P.)
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28
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Ciftci H, Tateishi H, Koiwai K, Koga R, Anraku K, Monde K, Dağ Ç, Destan E, Yuksel B, Ayan E, Yildirim G, Yigin M, Ertem FB, Shafiei A, Guven O, Besler SO, Sierra RG, Yoon CH, Su Z, Liang M, Acar B, Haliloglu T, Otsuka M, Yumoto F, Fujita M, Senda T, DeMirci H. Structural insight into host plasma membrane association and assembly of HIV-1 matrix protein. Sci Rep 2021; 11:15819. [PMID: 34349176 PMCID: PMC8339130 DOI: 10.1038/s41598-021-95236-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/15/2021] [Indexed: 11/25/2022] Open
Abstract
Oligomerization of Pr55Gag is a critical step of the late stage of the HIV life cycle. It has been known that the binding of IP6, an abundant endogenous cyclitol molecule at the MA domain, has been linked to the oligomerization of Pr55Gag. However, the exact binding site of IP6 on MA remains unknown and the structural details of this interaction are missing. Here, we present three high-resolution crystal structures of the MA domain in complex with IP6 molecules to reveal its binding mode. Additionally, extensive Differential Scanning Fluorimetry analysis combined with cryo- and ambient-temperature X-ray crystallography and GNM-based transfer entropy calculations identify the key residues that participate in IP6 binding. Our data provide novel insights about the multilayered HIV-1 virion assembly process that involves the interplay of IP6 with PIP2, a phosphoinositide essential for the binding of Pr55Gag to membrane. IP6 and PIP2 have neighboring alternate binding sites within the same highly basic region (residues 18-33). This indicates that IP6 and PIP2 bindings are not mutually exclusive and may play a key role in coordinating virion particles' membrane localization. Based on our three different IP6-MA complex crystal structures, we propose a new model that involves IP6 coordination of the oligomerization of outer MA and inner CA domain's 2D layers during assembly and budding.
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Affiliation(s)
- Halilibrahim Ciftci
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
- Department of Drug Discovery, Science Farm Ltd, Kumamoto, 862-0976, Japan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Hiroshi Tateishi
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Kotaro Koiwai
- Structural Biology Research Center, Institute of Materials Structure Science, KEK/High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801, Japan
| | - Ryoko Koga
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Kensaku Anraku
- Department of Medical Technology, Kumamoto Health Science University, Kumamoto, 861-5598, Japan
| | - Kazuaki Monde
- Department of Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan
| | - Çağdaş Dağ
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Ebru Destan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Busra Yuksel
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Esra Ayan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Gunseli Yildirim
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Merve Yigin
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - F Betul Ertem
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Alaleh Shafiei
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Omur Guven
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Sabri O Besler
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey
| | - Raymond G Sierra
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Chun Hong Yoon
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Zhen Su
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Applied Physics, Stanford University, Stanford, CA, USA
| | - Mengling Liang
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Burcin Acar
- Polymer Research Center, Bogazici University, 34342, Istanbul, Turkey
| | - Turkan Haliloglu
- Department of Chemical Engineering, Bogazici University, 34342, Istanbul, Turkey
- Polymer Research Center, Bogazici University, 34342, Istanbul, Turkey
| | - Masami Otsuka
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
- Department of Drug Discovery, Science Farm Ltd, Kumamoto, 862-0976, Japan
| | - Fumiaki Yumoto
- Structural Biology Research Center, Institute of Materials Structure Science, KEK/High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801, Japan
| | - Mikako Fujita
- Medicinal and Biological Chemistry Science Farm Joint Research Laboratory, Faculty of Life Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
| | - Toshiya Senda
- Structural Biology Research Center, Institute of Materials Structure Science, KEK/High Energy Accelerator Research Organization, Tsukuba, Ibaraki, 305-0801, Japan.
- School of High Energy Accelerator Science, SOKENDAI University, Tsukuba, Ibaraki, 305-0801, Japan.
- Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki, 305-8571, Japan.
| | - Hasan DeMirci
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.
- Department of Molecular Biology and Genetics, Koc University, 34450, Istanbul, Turkey.
- Koc University Isbank Center for Infectious Diseases (KUISCID), 34450, Istanbul, Turkey.
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29
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Protein N-myristoylation: functions and mechanisms in control of innate immunity. Cell Mol Immunol 2021; 18:878-888. [PMID: 33731917 PMCID: PMC7966921 DOI: 10.1038/s41423-021-00663-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/18/2021] [Indexed: 02/08/2023] Open
Abstract
Protein N-myristoylation is an important fatty acylation catalyzed by N-myristoyltransferases (NMTs), which are ubiquitous enzymes in eukaryotes. Specifically, attachment of a myristoyl group is vital for proteins participating in various biological functions, including signal transduction, cellular localization, and oncogenesis. Recent studies have revealed unexpected mechanisms indicating that protein N-myristoylation is involved in host defense against microbial and viral infections. In this review, we describe the current understanding of protein N-myristoylation (mainly focusing on myristoyl switches) and summarize its crucial roles in regulating innate immune responses, including TLR4-dependent inflammatory responses and demyristoylation-induced innate immunosuppression during Shigella flexneri infection. Furthermore, we examine the role of myristoylation in viral assembly, intracellular host interactions, and viral spread during human immunodeficiency virus-1 (HIV-1) infection. Deeper insight into the relationship between protein N-myristoylation and innate immunity might enable us to clarify the pathogenesis of certain infectious diseases and better harness protein N-myristoylation for new therapeutics.
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30
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Bussienne C, Marquet R, Paillart JC, Bernacchi S. Post-Translational Modifications of Retroviral HIV-1 Gag Precursors: An Overview of Their Biological Role. Int J Mol Sci 2021; 22:ijms22062871. [PMID: 33799890 PMCID: PMC8000049 DOI: 10.3390/ijms22062871] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/06/2021] [Accepted: 03/09/2021] [Indexed: 11/24/2022] Open
Abstract
Protein post-translational modifications (PTMs) play key roles in eukaryotes since they finely regulate numerous mechanisms used to diversify the protein functions and to modulate their signaling networks. Besides, these chemical modifications also take part in the viral hijacking of the host, and also contribute to the cellular response to viral infections. All domains of the human immunodeficiency virus type 1 (HIV-1) Gag precursor of 55-kDa (Pr55Gag), which is the central actor for viral RNA specific recruitment and genome packaging, are post-translationally modified. In this review, we summarize the current knowledge about HIV-1 Pr55Gag PTMs such as myristoylation, phosphorylation, ubiquitination, sumoylation, methylation, and ISGylation in order to figure out how these modifications affect the precursor functions and viral replication. Indeed, in HIV-1, PTMs regulate the precursor trafficking between cell compartments and its anchoring at the plasma membrane, where viral assembly occurs. Interestingly, PTMs also allow Pr55Gag to hijack the cell machinery to achieve viral budding as they drive recognition between viral proteins or cellular components such as the ESCRT machinery. Finally, we will describe and compare PTMs of several other retroviral Gag proteins to give a global overview of their role in the retroviral life cycle.
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31
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Lavado-García J, Díaz-Maneh A, Canal-Paulí N, Pérez-Rubio P, Gòdia F, Cervera L. Metabolic engineering of HEK293 cells to improve transient transfection and cell budding of HIV-1 virus-like particles. Biotechnol Bioeng 2021; 118:1649-1663. [PMID: 33463716 DOI: 10.1002/bit.27679] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 01/12/2021] [Indexed: 01/08/2023]
Abstract
HIV-1 Gag virus-like particles (VLPs) are promising candidates for the development of future vaccines. Recent viral outbreaks have manifested the need of robust vaccine production platforms able to adapt to new challenges while achieving mass production capacity. For the rapid production of VLPs, the method of transient gene expression (TGE) have proved highly efficient. Based on a previous characterization of the HEK293 cell line upon transient transfection using multiplexed quantitative proteomics, molecular production bottlenecks and metabolic pathways likely to be optimized were identified. In this study, these molecular components and metabolic pathways have been explored and modulated via transient metabolic engineering using approaches like design of experiments to fully exploit and optimize VLP production, transfection and budding efficiency. Upon overexpression of endosomal sorting complex required for transport accessory proteins like NEDD4L and CIT, VLP production increased 3.3 and 2.9-fold, respectively. Overexpression of glycosphingolipid precursor enzyme UGCG improved transfection efficiency by 17% and knocking-down the Gag-binding protein CNP improved 2.5-fold VLP specific productivity. Combining CNP inhibition and UGCG overexpression further improved budding efficiency by 37.3%. Modulating VLP production and accessory pathways like intracellular budding, demonstrated the potential of metabolic engineering to optimize and intensify the development of robust production platforms for future vaccines.
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Affiliation(s)
- Jesús Lavado-García
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Andy Díaz-Maneh
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Núria Canal-Paulí
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Pol Pérez-Rubio
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Francesc Gòdia
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Laura Cervera
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
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32
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Eastep GN, Ghanam RH, Green TJ, Saad JS. Structural characterization of HIV-1 matrix mutants implicated in envelope incorporation. J Biol Chem 2021; 296:100321. [PMID: 33485964 PMCID: PMC7952133 DOI: 10.1016/j.jbc.2021.100321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/05/2021] [Accepted: 01/20/2021] [Indexed: 11/28/2022] Open
Abstract
During the late phase of HIV-1 infection, viral Gag polyproteins are targeted to the plasma membrane (PM) for assembly. Gag localization at the PM is a prerequisite for the incorporation of the envelope protein (Env) into budding particles. Gag assembly and Env incorporation are mediated by the N-terminal myristoylated matrix (MA) domain of Gag. Nonconservative mutations in the trimer interface of MA (A45E, T70R, and L75G) were found to impair Env incorporation and infectivity, leading to the hypothesis that MA trimerization is an obligatory step for Env incorporation. Conversely, Env incorporation can be rescued by a compensatory mutation in the MA trimer interface (Q63R). The impact of these MA mutations on the structure and trimerization properties of MA is not known. In this study, we employed NMR spectroscopy, X-ray crystallography, and sedimentation techniques to characterize the structure and trimerization properties of HIV-1 MA A45E, Q63R, T70R, and L75G mutant proteins. NMR data revealed that these point mutations did not alter the overall structure and folding of MA but caused minor structural perturbations in the trimer interface. Analytical ultracentrifugation data indicated that mutations had a minimal effect on the MA monomer–trimer equilibrium. The high-resolution X-ray structure of the unmyristoylated MA Q63R protein revealed hydrogen bonding between the side chains of adjacent Arg-63 and Ser-67 on neighboring MA molecules, providing the first structural evidence for an additional intermolecular interaction in the trimer interface. These findings advance our knowledge of the interplay of MA trimerization and Env incorporation into HIV-1 particles.
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Affiliation(s)
- Gunnar N Eastep
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Ruba H Ghanam
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Todd J Green
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jamil S Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA.
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Abstract
Enveloped viruses exit producer cells and acquire their external lipid envelopes by budding through limiting cellular membranes. Most viruses encode multifunctional structural proteins that coordinate the processes of virion assembly, membrane envelopment, budding, and maturation. In many cases, the cellular ESCRT pathway is recruited to facilitate the membrane fission step of budding, but alternative strategies are also employed. Recently, many viruses previously considered to be non-enveloped have been shown to exit cells non-lytically within vesicles, adding further complexity to the intricacies of virus budding and egress.
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34
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Meusser B, Purfuerst B, Luft FC. HIV-1 Gag release from yeast reveals ESCRT interaction with the Gag N-terminal protein region. J Biol Chem 2020; 295:17950-17972. [PMID: 32994219 PMCID: PMC7939435 DOI: 10.1074/jbc.ra120.014710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/25/2020] [Indexed: 11/30/2022] Open
Abstract
The HIV-1 protein Gag assembles at the plasma membrane and drives virion budding, assisted by the cellular endosomal complex required for transport (ESCRT) proteins. Two ESCRT proteins, TSG101 and ALIX, bind to the Gag C-terminal p6 peptide. TSG101 binding is important for efficient HIV-1 release, but how ESCRTs contribute to the budding process and how their activity is coordinated with Gag assembly is poorly understood. Yeast, allowing genetic manipulation that is not easily available in human cells, has been used to characterize the cellular ESCRT function. Previous work reported Gag budding from yeast spheroplasts, but Gag release was ESCRT-independent. We developed a yeast model for ESCRT-dependent Gag release. We combined yeast genetics and Gag mutational analysis with Gag-ESCRT binding studies and the characterization of Gag-plasma membrane binding and Gag release. With our system, we identified a previously unknown interaction between ESCRT proteins and the Gag N-terminal protein region. Mutations in the Gag-plasma membrane-binding matrix domain that reduced Gag-ESCRT binding increased Gag-plasma membrane binding and Gag release. ESCRT knockout mutants showed that the release enhancement was an ESCRT-dependent effect. Similarly, matrix mutation enhanced Gag release from human HEK293 cells. Release enhancement partly depended on ALIX binding to p6, although binding site mutation did not impair WT Gag release. Accordingly, the relative affinity for matrix compared with p6 in GST-pulldown experiments was higher for ALIX than for TSG101. We suggest that a transient matrix-ESCRT interaction is replaced when Gag binds to the plasma membrane. This step may activate ESCRT proteins and thereby coordinate ESCRT function with virion assembly.
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Affiliation(s)
- Birgit Meusser
- Charité Medical Faculty, Berlin, Germany; Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | | | - Friedrich C Luft
- Charité Medical Faculty, Berlin, Germany; Max-Delbrück-Center for Molecular Medicine, Berlin, Germany; Experimental and Clinical Research Center, Berlin, Germany.
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35
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Boyd PS, Brown JB, Brown JD, Catazaro J, Chaudry I, Ding P, Dong X, Marchant J, O’Hern CT, Singh K, Swanson C, Summers MF, Yasin S. NMR Studies of Retroviral Genome Packaging. Viruses 2020; 12:v12101115. [PMID: 33008123 PMCID: PMC7599994 DOI: 10.3390/v12101115] [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: 08/04/2020] [Revised: 09/18/2020] [Accepted: 09/26/2020] [Indexed: 12/03/2022] Open
Abstract
Nearly all retroviruses selectively package two copies of their unspliced RNA genomes from a cellular milieu that contains a substantial excess of non-viral and spliced viral RNAs. Over the past four decades, combinations of genetic experiments, phylogenetic analyses, nucleotide accessibility mapping, in silico RNA structure predictions, and biophysical experiments were employed to understand how retroviral genomes are selected for packaging. Genetic studies provided early clues regarding the protein and RNA elements required for packaging, and nucleotide accessibility mapping experiments provided insights into the secondary structures of functionally important elements in the genome. Three-dimensional structural determinants of packaging were primarily derived by nuclear magnetic resonance (NMR) spectroscopy. A key advantage of NMR, relative to other methods for determining biomolecular structure (such as X-ray crystallography), is that it is well suited for studies of conformationally dynamic and heterogeneous systems—a hallmark of the retrovirus packaging machinery. Here, we review advances in understanding of the structures, dynamics, and interactions of the proteins and RNA elements involved in retroviral genome selection and packaging that are facilitated by NMR.
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36
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Interaction Interface of Mason-Pfizer Monkey Virus Matrix and Envelope Proteins. J Virol 2020; 94:JVI.01146-20. [PMID: 32796061 DOI: 10.1128/jvi.01146-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/03/2020] [Indexed: 02/06/2023] Open
Abstract
Retroviral envelope glycoprotein (Env) is essential for the specific recognition of the host cell and the initial phase of infection. As reported for human immunodeficiency virus (HIV), the recruitment of Env into a retroviral membrane envelope is mediated through its interaction with a Gag polyprotein precursor of structural proteins. This interaction, occurring between the matrix domain (MA) of Gag and the cytoplasmic tail (CT) of the transmembrane domain of Env, takes place at the host cell plasma membrane. To determine whether the MA of Mason-Pfizer monkey virus (M-PMV) also interacts directly with the CT of Env, we mimicked the in vivo conditions in an in vitro experiment by using a CT in its physiological trimeric conformation mediated by the trimerization motif of the GCN4 yeast transcription factor. The MA protein was used at the concentration shifting the equilibrium to its trimeric form. The direct interaction between MA and CT was confirmed by a pulldown assay. Through the combination of nuclear magnetic resonance (NMR) spectroscopy and protein cross-linking followed by mass spectrometry analysis, the residues involved in mutual interactions were determined. NMR has shown that the C terminus of the CT is bound to the C-terminal part of MA. In addition, protein cross-linking confirmed the close proximity of the N-terminal part of CT and the N terminus of MA, which is enabled in vivo by their location at the membrane. These results are in agreement with the previously determined orientation of MA on the membrane and support the already observed mechanisms of M-PMV virus-like particle transport and budding.IMPORTANCE By a combination of nuclear magnetic resonance (NMR) and mass spectroscopy of cross-linked peptides, we show that in contrast to human immunodeficiency virus type 1 (HIV-1), the C-terminal residues of the unstructured cytoplasmic tail of Mason-Pfizer monkey virus (M-PMV) Env interact with the matrix domain (MA). Based on biochemical data and molecular modeling, we propose that individual cytoplasmic tail (CT) monomers of a trimeric complex bind MA molecules belonging to different neighboring trimers, which may stabilize the MA orientation at the membrane by the formation of a membrane-bound net of interlinked Gag and CT trimers. This also corresponds with the concept that the membrane-bound MA of Gag recruits Env through interaction with the full-length CT, while CT truncation during maturation attenuates the interaction to facilitate uncoating. We propose a model suggesting different arrangements of MA-CT complexes between a D-type and C-type retroviruses with short and long CTs, respectively.
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Monje-Galvan V, Voth GA. Binding mechanism of the matrix domain of HIV-1 gag on lipid membranes. eLife 2020; 9:58621. [PMID: 32808928 PMCID: PMC7476761 DOI: 10.7554/elife.58621] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/14/2020] [Indexed: 01/10/2023] Open
Abstract
Specific protein-lipid interactions are critical for viral assembly. We present a molecular dynamics simulation study on the binding mechanism of the membrane targeting domain of HIV-1 Gag protein. The matrix (MA) domain drives Gag onto the plasma membrane through electrostatic interactions at its highly-basic-region (HBR), located near the myristoylated (Myr) N-terminus of the protein. Our study suggests Myr insertion is involved in the sorting of membrane lipids around the protein-binding site to prepare it for viral assembly. Our realistic membrane models confirm interactions with PIP2 and PS lipids are highly favored around the HBR and are strong enough to keep the protein bound even without Myr insertion. We characterized Myr insertion events from microsecond trajectories and examined the membrane response upon initial membrane targeting by MA. Insertion events only occur with one of the membrane models, showing a combination of surface charge and internal membrane structure modulate this process.
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Affiliation(s)
- Viviana Monje-Galvan
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, United States
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, United States
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How HIV-1 Gag Manipulates Its Host Cell Proteins: A Focus on Interactors of the Nucleocapsid Domain. Viruses 2020; 12:v12080888. [PMID: 32823718 PMCID: PMC7471995 DOI: 10.3390/v12080888] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 12/27/2022] Open
Abstract
The human immunodeficiency virus (HIV-1) polyprotein Gag (Group-specific antigen) plays a central role in controlling the late phase of the viral lifecycle. Considered to be only a scaffolding protein for a long time, the structural protein Gag plays determinate and specific roles in HIV-1 replication. Indeed, via its different domains, Gag orchestrates the specific encapsidation of the genomic RNA, drives the formation of the viral particle by its auto-assembly (multimerization), binds multiple viral proteins, and interacts with a large number of cellular proteins that are needed for its functions from its translation location to the plasma membrane, where newly formed virions are released. Here, we review the interactions between HIV-1 Gag and 66 cellular proteins. Notably, we describe the techniques used to evidence these interactions, the different domains of Gag involved, and the implications of these interactions in the HIV-1 replication cycle. In the final part, we focus on the interactions involving the highly conserved nucleocapsid (NC) domain of Gag and detail the functions of the NC interactants along the viral lifecycle.
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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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Wen Y, Feigenson GW, Vogt VM, Dick RA. Mechanisms of PI(4,5)P2 Enrichment in HIV-1 Viral Membranes. J Mol Biol 2020; 432:5343-5364. [PMID: 32739462 PMCID: PMC8262684 DOI: 10.1016/j.jmb.2020.07.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/12/2020] [Accepted: 07/26/2020] [Indexed: 01/10/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP2) is critical for HIV-1 virus assembly. The viral membrane is enriched in PIP2, suggesting that the virus assembles at PIP2-rich microdomains. We showed previously that in model membranes PIP2 can form nanoscopic clusters bridged by multivalent cations. Here, using purified proteins we quantitated the binding of HIV-1 Gag-related proteins to giant unilamellar vesicles containing either clustered or free PIP2. Myristoylated MA strongly preferred binding to clustered PIP2. By contrast, unmyristoylated HIV-1 MA, RSV MA, and a PH domain all preferred to interact with free PIP2. We also found that HIV-1 Gag multimerization promotes PIP2 clustering. Truncated Gag proteins comprising the MA, CA, and SP domains (MACASP) or the MA and CA domains (MACA) induced self-quenching of acyl chain-labeled fluorescent PIP2 in liposomes, implying clustering. However, HIV-1 MA itself did not induce PIP2 clustering. A CA inter-hexamer dimer interface mutation led to a loss of induced PIP2 clustering in MACA, indicating the importance of protein multimerization. Cryo-electron tomography of liposomes with bound MACA showed an amorphous protein layer on the membrane surface. Thus, it appears that while protein–protein interactions are required for PIP2 clustering, formation of a regular lattice is not. Protein-induced PIP2 clustering and multivalent cation-induced PIP2 clustering are additive. Taken together, these results provide the first evidence that HIV-1 Gag can selectively target pre-existing PIP2-enriched domains of the plasma membrane for viral assembly, and that Gag multimerization can further enrich PIP2 at assembly sites. These effects could explain the observed PIP2 enrichment in HIV-1.
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Affiliation(s)
- Yi Wen
- Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Gerald W Feigenson
- Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Volker M Vogt
- Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Robert A Dick
- Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY 14853, USA.
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Pérez Socas LB, Ambroggio EE. The influence of myristoylation, liposome surface charge and nucleic acid interaction in the partition properties of HIV-1 Gag-N-terminal peptides to membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183421. [PMID: 32710855 DOI: 10.1016/j.bbamem.2020.183421] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/25/2020] [Accepted: 07/07/2020] [Indexed: 01/10/2023]
Abstract
The group-specific antigen (GAG) polyprotein of HIV-1 is the main coordinator of the virus assembly process at the plasma membrane (PM) and is directed by its N-terminal matrix domain (MA). MA is myristoylated and possess a highly basic region (HBR) responsible for the interaction with the negative lipids of the PM, especially with PIP2. In addition, MA binds RNA molecules proposed as a regulatory step of the assembly process. Here we study the interaction of a synthetic peptide (N-terminal 21 amino acids of MA) and liposomes of different compositions using a variety of biophysical techniques. Particularly, we use the fluorescence properties of the single tryptophan of the peptide to analyze its partition to membranes, where we harness for first time the analytical ability of spectral phasors method to study this interaction. We found that electrostatic interactions play an important role for peptide partition to membranes and myristoylation reduces the free energy of the process. Interestingly, we observe that while the presence of PIP2 does not cause measurable changes on the peptide-membrane interaction, the interaction is favored by cholesterol. Additionally, we found that the partition process goes through a transition state involving peptide disaggregation and changes in the peptide secondary structure. On the other hand, we found that the presence of oligonucleotides competes with the interaction with lipids by increasing peptide solubility. In summary, we think that our results, in context of the current knowledge of the role of HIV-1 MA, contribute to a better molecular understanding of the membrane association process.
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Affiliation(s)
- Luis Benito Pérez Socas
- Universidad Nacional de Córdoba, Facultad de Ciencias Químicas, Departamento de Química Biológica-Ranwel Caputto, Haya de la Torre y Medina Allende s/n, Córdoba X5000HUA, Argentina; CONICET, Universidad Nacional de Córdoba, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Haya de la Torre y Medina Allende s/n, Córdoba X5000HUA, Argentina
| | - Ernesto Esteban Ambroggio
- Universidad Nacional de Córdoba, Facultad de Ciencias Químicas, Departamento de Química Biológica-Ranwel Caputto, Haya de la Torre y Medina Allende s/n, Córdoba X5000HUA, Argentina; CONICET, Universidad Nacional de Córdoba, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Haya de la Torre y Medina Allende s/n, Córdoba X5000HUA, Argentina.
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Sengupta P, Lippincott-Schwartz J. Revisiting Membrane Microdomains and Phase Separation: A Viral Perspective. Viruses 2020; 12:v12070745. [PMID: 32664429 PMCID: PMC7412473 DOI: 10.3390/v12070745] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/29/2020] [Accepted: 07/07/2020] [Indexed: 12/11/2022] Open
Abstract
Retroviruses selectively incorporate a specific subset of host cell proteins and lipids into their outer membrane when they bud out from the host plasma membrane. This specialized viral membrane composition is critical for both viral survivability and infectivity. Here, we review recent findings from live cell imaging of single virus assembly demonstrating that proteins and lipids sort into the HIV retroviral membrane by a mechanism of lipid-based phase partitioning. The findings showed that multimerizing HIV Gag at the assembly site creates a liquid-ordered lipid phase enriched in cholesterol and sphingolipids. Proteins with affinity for this specialized lipid environment partition into it, resulting in the selective incorporation of proteins into the nascent viral membrane. Building on this and other work in the field, we propose a model describing how HIV Gag induces phase separation of the viral assembly site through a mechanism involving transbilayer coupling of lipid acyl chains and membrane curvature changes. Similar phase-partitioning pathways in response to multimerizing structural proteins likely help sort proteins into the membranes of other budding structures within cells.
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Type I Phosphatidylinositol-4-Phosphate 5-Kinases α and γ Play a Key Role in Targeting HIV-1 Pr55 Gag to the Plasma Membrane. J Virol 2020; 94:JVI.00189-20. [PMID: 32376619 DOI: 10.1128/jvi.00189-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/28/2020] [Indexed: 12/31/2022] Open
Abstract
HIV-1 assembly occurs principally at the plasma membrane (PM) of infected cells. Gag polyprotein precursors (Pr55Gag) are targeted to the PM, and their binding is mediated by the interaction of myristoylated matrix domain and a PM-specific phosphoinositide, the phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2]. The major synthesis pathway of PI(4,5)P2 involves the activity of phosphatidylinositol-4-phosphate 5-kinase family type 1 composed of three isoforms (PIP5K1α, PIP5K1β, and PIP5K1γ). To examine whether the activity of a specific PIP5K1 isoform determines proper Pr55Gag localization at the PM, we compared the cellular behavior of Pr55Gag in the context of PIP5K1 inhibition using siRNAs that individually targeted each of the three isoforms in TZM-bl HeLa cells. We found that downregulation of PIP5K1α and PIP5K1γ strongly impaired the targeting of Pr55Gag to the PM with a rerouting of the polyprotein within intracellular compartments. The efficiency of Pr55Gag release was thus impaired through the silencing of these two isoforms, while PIP5K1β is dispensable for Pr55Gag targeting to the PM. The PM mistargeting due to the silencing of PIP5K1α leads to Pr55Gag hydrolysis through lysosome and proteasome pathways, while the silencing of PIP5K1γ leads to Pr55Gag accumulation in late endosomes. Our findings demonstrated that, within the PIP5K1 family, only the PI(4,5)P2 pools produced by PIP5K1α and PIP5K1γ are involved in the Pr55Gag PM targeting process.IMPORTANCE PM specificity of Pr55Gag membrane binding is mediated through the interaction of PI(4,5)P2 with the matrix (MA) basic residues. It was shown that overexpression of a PI(4,5)P2-depleting enzyme strongly impaired PM localization of Pr55Gag However, cellular factors that control PI(4,5)P2 production required for Pr55Gag-PM targeting have not yet been characterized. In this study, by individually inhibiting PIP5K1 isoforms, we elucidated a correlation between PI(4,5)P2 metabolism pathways mediated by PIP5K1 isoforms and the targeting of Pr55Gag to the PM of TZM-bl HeLa cells. Confocal microscopy analyses of cells depleted from PIP5K1α and PIP5K1γ show a rerouting of Pr55Gag to various intracellular compartments. Notably, Pr55Gag is degraded by the proteasome and/or by the lysosomes in PIP5K1α-depleted cells, while Pr55Gag is targeted to endosomal vesicles in PIP5K1γ-depleted cells. Thus, our results highlight, for the first time, the roles of PIP5K1α and PIP5K1γ as determinants of Pr55Gag targeting to the PM.
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Brown JB, Summers HR, Brown LA, Marchant J, Canova PN, O'Hern CT, Abbott ST, Nyaunu C, Maxwell S, Johnson T, Moser MB, Ablan SD, Carter H, Freed EO, Summers MF. Structural and Mechanistic Studies of the Rare Myristoylation Signal of the Feline Immunodeficiency Virus. J Mol Biol 2020; 432:4076-4091. [PMID: 32442659 PMCID: PMC7316625 DOI: 10.1016/j.jmb.2020.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 10/24/2022]
Abstract
All retroviruses encode a Gag polyprotein containing an N-terminal matrix domain (MA) that anchors Gag to the plasma membrane and recruits envelope glycoproteins to virus assembly sites. Membrane binding by the Gag protein of HIV-1 and most other lentiviruses is dependent on N-terminal myristoylation of MA by host N-myristoyltransferase enzymes (NMTs), which recognize a six-residue "myristoylation signal" with consensus sequence: M1GXXX[ST]. For unknown reasons, the feline immunodeficiency virus (FIV), which infects both domestic and wild cats, encodes a non-consensus myristoylation sequence not utilized by its host or by other mammals (most commonly: M1GNGQG). To explore the evolutionary basis for this sequence, we compared the structure, dynamics, and myristoylation properties of native FIV MA with a mutant protein containing a consensus feline myristoylation motif (MANOS) and examined the impact of MA mutations on virus assembly and ability to support spreading infection. Unexpectedly, myristoylation efficiency of MANOS in Escherichia coli by co-expressed mammalian NMT was reduced by ~70% compared to the wild-type protein. NMR studies revealed that residues of the N-terminal myristoylation signal are fully exposed and mobile in the native protein but partially sequestered in the MANOS chimera, suggesting that the unusual FIV sequence is conserved to promote exposure and efficient myristoylation of the MA N terminus. In contrast, virus assembly studies indicate that the MANOS mutation does not affect virus assembly, but does prevent virus spread, in feline kidney cells. Our findings indicate that residues of the FIV myristoylation sequence play roles in replication beyond NMT recognition and Gag-membrane binding.
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Affiliation(s)
- Janae B Brown
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Holly R Summers
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Lola A Brown
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Jan Marchant
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Paige N Canova
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Colin T O'Hern
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Sophia T Abbott
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Constance Nyaunu
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Simon Maxwell
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Talayah Johnson
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Morgan B Moser
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Sherimay D Ablan
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, National Cancer Institute at Fredrick, Fredrick, MD 21702-1201, USA
| | - Hannah Carter
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, National Cancer Institute at Fredrick, Fredrick, MD 21702-1201, USA
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, National Cancer Institute at Fredrick, Fredrick, MD 21702-1201, USA.
| | - Michael F Summers
- Howard Hughes Medical Institute and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA.
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Murphy RE, Saad JS. The Interplay between HIV-1 Gag Binding to the Plasma Membrane and Env Incorporation. Viruses 2020; 12:E548. [PMID: 32429351 PMCID: PMC7291237 DOI: 10.3390/v12050548] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 12/21/2022] Open
Abstract
Advancement in drug therapies and patient care have drastically improved the mortality rates of HIV-1 infected individuals. Many of these therapies were developed or improved upon by using structure-based techniques, which underscore the importance of understanding essential mechanisms in the replication cycle of HIV-1 at the structural level. One such process which remains poorly understood is the incorporation of the envelope glycoprotein (Env) into budding virus particles. Assembly of HIV particles is initiated by targeting of the Gag polyproteins to the inner leaflet of the plasma membrane (PM), a process mediated by the N-terminally myristoylated matrix (MA) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). There is strong evidence that formation of the Gag lattice on the PM is a prerequisite for the incorporation of Env into budding particles. It is also suggested that Env incorporation is mediated by an interaction between its cytoplasmic tail (gp41CT) and the MA domain of Gag. In this review, we highlight the latest developments and current efforts to understand the interplay between gp41CT, MA, and the membrane during assembly. Elucidation of the molecular determinants of Gag-Env-membrane interactions may help in the development of new antiviral therapeutic agents that inhibit particle assembly, Env incorporation and ultimately virus production.
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Affiliation(s)
| | - Jamil S. Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
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Junková P, Pleskot R, Prchal J, Sýs J, Ruml T. Differences and commonalities in plasma membrane recruitment of the two morphogenetically distinct retroviruses HIV-1 and MMTV. J Biol Chem 2020; 295:8819-8833. [PMID: 32385109 DOI: 10.1074/jbc.ra119.011991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 05/05/2020] [Indexed: 11/06/2022] Open
Abstract
Retroviral Gag polyproteins are targeted to the inner leaflet of the plasma membrane through their N-terminal matrix (MA) domain. Because retroviruses of different morphogenetic types assemble their immature particles in distinct regions of the host cell, the mechanism of MA-mediated plasma membrane targeting differs among distinct retroviral morphogenetic types. Here, we focused on possible mechanistic differences of the MA-mediated plasma membrane targeting of the B-type mouse mammary tumor virus (MMTV) and C-type HIV-1, which assemble in the cytoplasm and at the plasma membrane, respectively. Molecular dynamics simulations, together with surface mapping, indicated that, similarly to HIV-1, MMTV uses a myristic switch to anchor the MA to the membrane and electrostatically interacts with phosphatidylinositol 4,5-bisphosphate to stabilize MA orientation. We observed that the affinity of MMTV MA to the membrane is lower than that of HIV-1 MA, possibly related to their different topologies and the number of basic residues in the highly basic MA region. The latter probably reflects the requirement of C-type retroviruses for tighter membrane binding, essential for assembly, unlike for D/B-type retroviruses, which assemble in the cytoplasm. A comparison of the membrane topology of the HIV-1 MA, using the surface-mapping method and molecular dynamics simulations, revealed that the residues at the HIV-1 MA C terminus help stabilize protein-protein interactions within the HIV-1 MA lattice at the plasma membrane. In summary, HIV-1 and MMTV share common features such as membrane binding of the MA via hydrophobic interactions and exhibit several differences, including lower membrane affinity of MMTV MA.
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Affiliation(s)
- Petra Junková
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Roman Pleskot
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium; VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Jan Prchal
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
| | - Jakub Sýs
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
| | - Tomáš Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic.
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Dick A, Cocklin S. Recent Advances in HIV-1 Gag Inhibitor Design and Development. Molecules 2020; 25:molecules25071687. [PMID: 32272714 PMCID: PMC7181048 DOI: 10.3390/molecules25071687] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/31/2020] [Accepted: 04/05/2020] [Indexed: 02/06/2023] Open
Abstract
Acquired Immune Deficiency Syndrome (AIDS) treatment with combination antiretroviral therapy (cART) has improved the life quality of many patients since its implementation. However, resistance mutations and the accumulation of severe side effects associated with cART remain enormous challenges that need to be addressed with the continual design and redesign of anti-HIV drugs. In this review, we focus on the importance of the HIV-1 Gag polyprotein as the master coordinator of HIV-1 assembly and maturation and as an emerging drug target. Due to its multiple roles in the HIV-1 life cycle, the individual Gag domains are attractive but also challenging targets for inhibitor design. However, recent encouraging developments in targeting the Gag domains such as the capsid protein with highly potent and potentially long-acting inhibitors, as well as the exploration and successful targeting of challenging HIV-1 proteins such as the matrix protein, have demonstrated the therapeutic viability of this important protein. Such Gag-directed inhibitors have great potential for combating the AIDS pandemic and to be useful tools to dissect HIV-1 biology.
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48
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Angert I, Karuka SR, Hennen J, Chen Y, Albanesi JP, Mansky LM, Mueller JD. Sensitive Detection of Protein Binding to the Plasma Membrane with Dual-Color Z-Scan Fluorescence. Biophys J 2020; 118:281-293. [PMID: 31870539 DOI: 10.1016/j.bpj.2019.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 11/22/2019] [Accepted: 12/03/2019] [Indexed: 11/25/2022] Open
Abstract
Delicate and transitory protein engagement at the plasma membrane (PM) is crucial to a broad range of cellular functions, including cell motility, signal transduction, and virus replication. Here, we describe a dual-color (DC) extension of the fluorescence z-scan technique, which has proven successful for quantification of peripheral membrane protein binding to the PM in living cells. We demonstrate that the coexpression of a second, distinctly colored fluorescent protein provides a soluble reference species that delineates the extent of the cell cytoplasm and lowers the detection threshold of z-scan PM-binding measurements by an order of magnitude. DC z-scan generates an intensity profile for each detection channel that contains information on the axial distribution of the peripheral membrane and reference protein. Fit models for DC z-scan are developed and verified using simple model systems. Next, we apply the quantitative DC z-scan technique to investigate the binding of two peripheral membrane protein systems for which previous z-scan studies failed to detect binding: human immunodeficiency virus type 1 (HIV-1) matrix (MA) protein and lipidation-deficient mutants of the fibroblast growth factor receptor substrate 2α. Our findings show that these mutations severely disrupt PM association of fibroblast growth factor receptor substrate 2α but do not eliminate it. We further detected binding of HIV-1 MA to the PM using DC z-scan. Interestingly, our data indicate that HIV-1 MA binds cooperatively to the PM with a dissociation coefficient of Kd ∼16 μM and Hill coefficient of n ∼2.
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Affiliation(s)
- Isaac Angert
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota
| | | | - Jared Hennen
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota
| | - Yan Chen
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota; Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota
| | - Joseph P Albanesi
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota; Division of Basic Sciences, University of Minnesota, Minneapolis, Minnesota; School of Dentistry, University of Minnesota, Minneapolis, Minnesota
| | - Joachim D Mueller
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota; Institute for Molecular Virology, University of Minnesota, Minneapolis, Minnesota; Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota.
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Relationships between MA-RNA Binding in Cells and Suppression of HIV-1 Gag Mislocalization to Intracellular Membranes. J Virol 2019; 93:JVI.00756-19. [PMID: 31511376 DOI: 10.1128/jvi.00756-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 09/02/2019] [Indexed: 12/24/2022] Open
Abstract
The HIV-1 Gag matrix (MA) domain mediates the localization of Gag to the plasma membrane (PM), the site for infectious virion assembly. The MA highly basic region (MA-HBR) interacts with phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2], a PM-specific acidic lipid. The MA-HBR also binds RNAs. To test whether acidic lipids alone determine PM-specific localization of Gag or whether MA-RNA binding also plays a role, we compared a panel of MA-HBR mutants that contain two types of substitutions at MA residues 25 and 26 or residues 29 and 31: Lys→Arg (KR) (25/26KR and 29/31KR) and Lys→Thr (KT) (25/26KT and 29/31KT). Consistent with the importance of the HBR charge in RNA binding, both KT mutants failed to bind RNA via MA efficiently, unlike the corresponding KR mutants. Both 25/26KT Gag-yellow fluorescent protein (YFP) and 29/31KT Gag-YFP bound nonspecifically to the PM and intracellular membranes, presumably via the myristoyl moiety and remaining MA basic residues. In contrast, 25/26KR Gag-YFP bound specifically to the PM, suggesting a role for the total positive charge and/or MA-bound RNA in navigating Gag to the PM. Unlike 29/31KT Gag-YFP, 29/31KR Gag-YFP was predominantly cytosolic and showed little intracellular membrane binding despite having a higher HBR charge. Therefore, it is likely that MA-RNA binding blocks promiscuous Gag membrane binding in cells. Notably, the introduction of a heterologous multimerization domain restored PI(4,5)P2-dependent PM-specific localization for 29/31KR Gag-YFP, suggesting that the blocking of PM binding is more readily reversed than that of intracellular membrane binding. Altogether, these cell-based data support a model in which MA-RNA binding ensures PM-specific localization of Gag via suppression of nonspecific membrane binding.IMPORTANCE The PM-specific localization of HIV-1 Gag is a crucial early step in infectious progeny production. The interaction between the MA highly basic region (MA-HBR) of Gag and the PM-specific lipid PI(4,5)P2 is critical for Gag localization to the PM. Additionally, in vitro evidence has indicated that MA-RNA binding prevents nonspecific binding of Gag to non-PI(4,5)P2-containing membranes. However, cell-based evidence supporting a role for HIV-1 MA-RNA binding in PM-specific subcellular localization has been scarce; thus, it remained possible that in cells, just the high basic charge or the PI(4,5)P2 binding ability is sufficient for MA to direct Gag specifically to the PM. The present study reveals for the first time an excellent correlation between RNA binding of the MA-HBR and inhibition of promiscuous Gag localization, both within the cells, and thereby provides cell-based evidence supporting a mechanism in which HIV-1 MA binding to RNA ensures the specific localization of Gag to the PM.
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50
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Zhao H, Datta SAK, Kim SH, To SC, Chaturvedi SK, Rein A, Schuck P. Nucleic acid-induced dimerization of HIV-1 Gag protein. J Biol Chem 2019; 294:16480-16493. [PMID: 31570521 PMCID: PMC6851336 DOI: 10.1074/jbc.ra119.010580] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/20/2019] [Indexed: 01/09/2023] Open
Abstract
HIV-1 Gag is a highly flexible multidomain protein that forms the protein lattice of the immature HIV-1 virion. In vitro, it reversibly dimerizes, but in the presence of nucleic acids (NAs), it spontaneously assembles into virus-like particles (VLPs). High-resolution structures have revealed intricate details of the interactions of the capsid (CA) domain of Gag and the flanking spacer peptide SP1 that stabilize VLPs, but much less is known about the assembly pathway and the interactions of the highly flexible NA-binding nucleocapsid (NC) domain. Here, using a novel hybrid fluorescence proximity/sedimentation velocity method in combination with calorimetric analyses, we studied initial binding events by monitoring the sizes and conformations of complexes of Gag with very short oligonucleotides. We observed that high-affinity binding of oligonucleotides induces conformational changes in Gag accompanied by the formation of complexes with a 2:1 Gag/NA stoichiometry. This NA-liganded dimerization mode is distinct from the widely studied dimer interface in the CA domain and from protein interactions arising in the SP1 region and may be mediated by protein-protein interactions localized in the NC domain. The formation of the liganded dimer is strongly enthalpically driven, resulting in higher dimerization affinity than the CA-domain dimer. Both detailed energetic and conformational analyses of different Gag constructs revealed modulatory contributions to NA-induced dimerization from both matrix and CA domains. We hypothesize that allosterically controlled self-association represents the first step of VLP assembly and, in concert with scaffolding along the NA, can seed the formation of two-dimensional arrays near the NA.
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Affiliation(s)
- Huaying Zhao
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892
| | - Siddhartha A K Datta
- HIV Dynamics and Replication Program, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Sung H Kim
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892
| | - Samuel C To
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892
| | - Sumit K Chaturvedi
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892
| | - Alan Rein
- HIV Dynamics and Replication Program, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702
| | - Peter Schuck
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892
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