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Mangala Prasad V, Blijleven JS, Smit JM, Lee KK. Visualization of conformational changes and membrane remodeling leading to genome delivery by viral class-II fusion machinery. Nat Commun 2022; 13:4772. [PMID: 35970990 PMCID: PMC9378758 DOI: 10.1038/s41467-022-32431-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 07/31/2022] [Indexed: 11/09/2022] Open
Abstract
Chikungunya virus (CHIKV) is a human pathogen that delivers its genome to the host cell cytoplasm through endocytic low pH-activated membrane fusion mediated by class-II fusion proteins. Though structures of prefusion, icosahedral CHIKV are available, structural characterization of virion interaction with membranes has been limited. Here, we have used cryo-electron tomography to visualize CHIKV's complete membrane fusion pathway, identifying key intermediary glycoprotein conformations coupled to membrane remodeling events. Using sub-tomogram averaging, we elucidate features of the low pH-exposed virion, nucleocapsid and full-length E1-glycoprotein's post-fusion structure. Contrary to class-I fusion systems, CHIKV achieves membrane apposition by protrusion of extended E1-glycoprotein homotrimers into the target membrane. The fusion process also features a large hemifusion diaphragm that transitions to a wide pore for intact nucleocapsid delivery. Our analyses provide comprehensive ultrastructural insights into the class-II virus fusion system function and direct mechanistic characterization of the fundamental process of protein-mediated membrane fusion.
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Affiliation(s)
- Vidya Mangala Prasad
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA.,Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Jelle S Blijleven
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Jolanda M Smit
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Kelly K Lee
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA. .,Biological Physics, Structure and Design Graduate Program, University of Washington, Seattle, WA, USA. .,Department of Microbiology, University of Washington, Seattle, WA, USA.
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van der Borg G, Braddock S, Blijleven JS, van Oijen AM, Roos WH. Single-particle fusion of influenza viruses reveals complex interactions with target membranes. J Phys Condens Matter 2018; 30:204005. [PMID: 29623903 PMCID: PMC7104739 DOI: 10.1088/1361-648x/aabc21] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/27/2018] [Accepted: 04/06/2018] [Indexed: 05/03/2023]
Abstract
The first step in infection of influenza A virus is contact with the host cell membrane, with which it later fuses. The composition of the target bilayer exerts a complex influence on both fusion efficiency and time. Here, an in vitro, single-particle approach is used to study this effect. Using total internal reflection fluorescence (TIRF) microscopy and a microfluidic flow cell, the hemifusion of single virions is visualized. Hemifusion efficiency and kinetics are studied while altering target bilayer cholesterol content and sialic-acid donor. Cholesterol ratios tested were 0%, 10%, 20%, and 40%. Sialic-acid donors GD1a and GYPA were used. Both cholesterol ratio and sialic-acid donors proved to have a significant effect on hemifusion efficiency. Furthermore, comparison between GD1a and GYPA conditions shows that the cholesterol dependence of the hemifusion time is severely affected by the sialic-acid donor. Only GD1a shows a clear increasing trend in hemifusion efficiency and time with increasing cholesterol concentration of the target bilayer with maximum rates for GD1A and 40% cholesterol. Overall our results show that sialic acid donor and target bilayer composition should be carefully chosen, depending on the desired hemifusion time and efficiency in the experiment.
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Affiliation(s)
- Guus van der Borg
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Netherlands
| | - Scarlett Braddock
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Netherlands
| | - Jelle S Blijleven
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Netherlands
| | | | - Wouter H Roos
- Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Netherlands
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Abstract
Influenza hemagglutinin (HA) is a viral membrane protein responsible for the initial steps of the entry of influenza virus into the host cell. It mediates binding of the virus particle to the host-cell membrane and catalyzes fusion of the viral membrane with that of the host. HA is therefore a major target in the development of antiviral strategies. The fusion of two membranes involves high activation barriers and proceeds through several intermediate states. Here, we provide a biophysical description of the membrane fusion process, relating its kinetic and thermodynamic properties to the large conformational changes taking place in HA and placing these in the context of multiple HA proteins working together to mediate fusion. Furthermore, we highlight the role of novel single-particle experiments and computational approaches in understanding the fusion process and their complementarity with other biophysical approaches.
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Affiliation(s)
- Sander Boonstra
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands; , , , ,
| | - Jelle S Blijleven
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands; , , , ,
| | - Wouter H Roos
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands; , , , ,
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands; , , , ,
| | - Erik van der Giessen
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands; , , , ,
| | - Antoine M van Oijen
- School of Chemistry; Faculty of Science, Medicine and Health; University of Wollongong, Wollongong, New South Wales 2522, Australia;
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Blijleven JS, Boonstra S, Onck PR, van der Giessen E, van Oijen AM. Mechanisms of influenza viral membrane fusion. Semin Cell Dev Biol 2016; 60:78-88. [PMID: 27401120 DOI: 10.1016/j.semcdb.2016.07.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 06/28/2016] [Accepted: 07/07/2016] [Indexed: 11/18/2022]
Abstract
Influenza viral particles are enveloped by a lipid bilayer. A major step in infection is fusion of the viral and host cellular membranes, a process with large kinetic barriers. Influenza membrane fusion is catalyzed by hemagglutinin (HA), a class I viral fusion protein activated by low pH. The exact nature of the HA conformational changes that deliver the energy required for fusion remains poorly understood. This review summarizes our current knowledge of HA structure and dynamics, describes recent single-particle experiments and modeling studies, and discusses their role in understanding how multiple HAs mediate fusion. These approaches provide a mechanistic picture in which HAs independently and stochastically insert into the target membrane, forming a cluster of HAs that is collectively able to overcome the barrier to membrane fusion. The new experimental and modeling approaches described in this review hold promise for a more complete understanding of other viral fusion systems and the protein systems responsible for cellular fusion.
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Affiliation(s)
- Jelle S Blijleven
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Sander Boonstra
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Patrick R Onck
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Erik van der Giessen
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Antoine M van Oijen
- School of Chemistry, Faculty of Science, Medicine and Health, University of Wollongong, NSW 2522, Australia.
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van Duijl-Richter MKS, Blijleven JS, van Oijen AM, Smit JM. Chikungunya virus fusion properties elucidated by single-particle and bulk approaches. J Gen Virol 2015; 96:2122-2132. [DOI: 10.1099/vir.0.000144] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Mareike K. S. van Duijl-Richter
- Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands
| | - Jelle S. Blijleven
- Centre for Synthetic Biology, Zernike Institute of Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Antoine M. van Oijen
- Centre for Synthetic Biology, Zernike Institute of Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
- School of Chemistry, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Jolanda M. Smit
- Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands
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