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Sun W, Wang M, Shi Z, Wang P, Wang J, Du B, Wang S, Sun Z, Liu Z, Wei L, Yang D, He X, Wang J. VP2 mediates the release of the feline calicivirus RNA genome by puncturing the endosome membrane of infected cells. J Virol 2024; 98:e0035024. [PMID: 38591900 PMCID: PMC11092339 DOI: 10.1128/jvi.00350-24] [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: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 04/10/2024] Open
Abstract
Feline calicivirus (FCV) is one of the few members of the Caliciviridae family that grows well in cell lines and, therefore, serves as a surrogate to study the biology of other viruses in the family. Conley et al. (14) demonstrated that upon the receptor engagement to the capsid, FCV VP2 forms a portal-like assembly, which might provide a channel for RNA release. However, the process of calicivirus RNA release is not yet fully understood. Our findings suggest that the separation of the FCV capsid from its genome RNA (gRNA) occurs rapidly in the early endosomes of infected cells. Using a liposome model decorated with the FCV cell receptor fJAM-A, we demonstrate that FCV releases its gRNA into the liposomes by penetrating membranes under low pH conditions. Furthermore, we found that VP2, which is rich in hydrophobic residues at its N-terminus, functions as the pore-forming protein. When we substituted the VP2 N-terminal hydrophobic residues, the gRNA release efficacy of the FCV mutants decreased. In conclusion, our results suggest that in the acidic environment of early endosomes, FCV VP2 functions as the pore-forming protein to mediate gRNA release into the cytoplasm of infected cells. This provides insight into the mechanism of calicivirus genome release.IMPORTANCEResearch on the biology and pathogenicity of certain caliciviruses, such as Norovirus and Sapovirus, is hindered by the lack of easy-to-use cell culture system. Feline calicivirus (FCV), which grows effectively in cell lines, is used as a substitute. At present, there is limited understanding of the genome release mechanism in caliciviruses. Our findings suggest that FCV uses VP2 to pierce the endosome membrane for genome release and provide new insights into the calicivirus gRNA release mechanism.
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Affiliation(s)
- Weiyao Sun
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Ming Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhibin Shi
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Pengfei Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Jinhui Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Bingchen Du
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Shida Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhenzhao Sun
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zaisi Liu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lili Wei
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Decheng Yang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xijun He
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Jingfei Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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Charnesky AJ, Faust JE, Lee H, Puligedda RD, Goetschius DJ, DiNunno NM, Thapa V, Bator CM, Cho SHJ, Wahid R, Mahmood K, Dessain S, Chumakov KM, Rosenfeld A, Hafenstein SL. A human monoclonal antibody binds within the poliovirus receptor-binding site to neutralize all three serotypes. Nat Commun 2023; 14:6335. [PMID: 37816742 PMCID: PMC10564760 DOI: 10.1038/s41467-023-41052-9] [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: 08/19/2022] [Accepted: 08/17/2023] [Indexed: 10/12/2023] Open
Abstract
Global eradication of poliovirus remains elusive, and it is critical to develop next generation vaccines and antivirals. In support of this goal, we map the epitope of human monoclonal antibody 9H2 which is able to neutralize the three serotypes of poliovirus. Using cryo-EM we solve the near-atomic structures of 9H2 fragments (Fab) bound to capsids of poliovirus serotypes 1, 2, and 3. The Fab-virus complexes show that Fab interacts with the same binding mode for each serotype and at the same angle of interaction relative to the capsid surface. For each of the Fab-virus complexes, we find that the binding site overlaps with the poliovirus receptor (PVR) binding site and maps across and into a depression in the capsid called the canyon. No conformational changes to the capsid are induced by Fab binding for any complex. Competition binding experiments between 9H2 and PVR reveal that 9H2 impedes receptor binding. Thus, 9H2 outcompetes the receptor to neutralize poliovirus. The ability to neutralize all three serotypes, coupled with the critical importance of the conserved receptor binding site make 9H2 an attractive antiviral candidate for future development.
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Affiliation(s)
- Andrew J Charnesky
- Molecular, Cellular, and Integrative Biosciences Program, The Pennsylvania State University, University Park, PA, USA
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Julia E Faust
- Department of Biochemistry, The Pennsylvania State University, University Park, PA, USA
| | - Hyunwook Lee
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
- Department of Biochemistry, The Pennsylvania State University, University Park, PA, USA
| | - Rama Devudu Puligedda
- Lankenau Institute for Medical Research, Lankenau Medical Center, 100 East Lancaster Avenue, Wynnewood, PA, 19096, USA
| | - Daniel J Goetschius
- Molecular, Cellular, and Integrative Biosciences Program, The Pennsylvania State University, University Park, PA, USA
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Nadia M DiNunno
- Molecular, Cellular, and Integrative Biosciences Program, The Pennsylvania State University, University Park, PA, USA
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Vaskar Thapa
- Department of Biochemistry, The Pennsylvania State University, University Park, PA, USA
| | - Carol M Bator
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Sung Hyun Joseph Cho
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Rahnuma Wahid
- Center for Vaccine Innovation and Access, PATH, Seattle, WA, 98121, USA
| | - Kutub Mahmood
- Center for Vaccine Innovation and Access, PATH, Seattle, WA, 98121, USA
| | - Scott Dessain
- Lankenau Institute for Medical Research, Lankenau Medical Center, 100 East Lancaster Avenue, Wynnewood, PA, 19096, USA
| | - Konstantin M Chumakov
- Office of Vaccines Research and Review, Division of Viral Products, Laboratory of Method Development, FDA, Silver Spring, MD, USA
| | - Amy Rosenfeld
- Office of Vaccines Research and Review, Division of Viral Products, Laboratory of Method Development, FDA, Silver Spring, MD, USA
| | - Susan L Hafenstein
- Molecular, Cellular, and Integrative Biosciences Program, The Pennsylvania State University, University Park, PA, USA.
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA.
- Department of Biochemistry, The Pennsylvania State University, University Park, PA, USA.
- Department of Medicine, The Pennsylvania State University College of Medicine, Hershey, PA, USA.
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3
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Wang Q, Meng H, Ge D, Shan H, Geri L, Liu F. Structural and nonstructural proteins of Senecavirus A: Recent research advances, and lessons learned from those of other picornaviruses. Virology 2023; 585:155-163. [PMID: 37348144 DOI: 10.1016/j.virol.2023.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/04/2023] [Accepted: 06/06/2023] [Indexed: 06/24/2023]
Abstract
Senecavirus A (SVA) is an emerging virus, causing vesicular disease in swine. SVA is a single-stranded, positive-sense RNA virus, which is the only member of the genus Senecavirus in the family Picornaviridae. SVA genome encodes 12 proteins: L, VP4, VP2, VP3, VP1, 2A, 2B, 2C, 3A, 3B, 3C and 3D. The VP1 to VP4 are structural proteins, and the others are nonstructural proteins. The replication of SVA in host cells is a complex process coordinated by an elaborate interplay between the structural and nonstructural proteins. Structural proteins are primarily involved in the invasion and assembly of virions. Nonstructural proteins modulate viral RNA translation and replication, and also take part in antagonizing the antiviral host response and in disrupting some cellular processes to allow virus replication. Here, we systematically reviewed the molecular functions of SVA structural and nonstructural proteins by reference to literatures of SVA itself and other picornaviruses.
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Affiliation(s)
- Qianqian Wang
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, 266109, China; College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, 010011, China
| | - Hailan Meng
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, 266109, China
| | - Dong Ge
- Qingdao Lijian Bio-tech Co., Ltd., Qingdao, 266114, China
| | - Hu Shan
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, 266109, China
| | - Letu Geri
- College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, 010011, China.
| | - Fuxiao Liu
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, 266109, China.
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Winter SL, Chlanda P. The Art of Viral Membrane Fusion and Penetration. Subcell Biochem 2023; 106:113-152. [PMID: 38159225 DOI: 10.1007/978-3-031-40086-5_4] [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] [Indexed: 01/03/2024]
Abstract
As obligate pathogens, viruses have developed diverse mechanisms to deliver their genome across host cell membranes to sites of virus replication. While enveloped viruses utilize viral fusion proteins to accomplish fusion of their envelope with the cellular membrane, non-enveloped viruses rely on machinery that causes local membrane ruptures and creates an opening through which the capsid or viral genome is released. Both membrane fusion and membrane penetration take place at the plasma membrane or in intracellular compartments, often involving the engagement of the cellular machinery and antagonism of host restriction factors. Enveloped and non-enveloped viruses have evolved intricate mechanisms to enable virus uncoating and modulation of membrane fusion in a spatiotemporally controlled manner. This chapter summarizes and discusses the current state of understanding of the mechanisms of viral membrane fusion and penetration. The focus is on the role of lipids, viral scaffold uncoating, viral membrane fusion inhibitors, and host restriction factors as physicochemical modulators. In addition, recent advances in visualizing and detecting viral membrane fusion and penetration using cryo-electron microscopy methods are presented.
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Affiliation(s)
- Sophie L Winter
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - Petr Chlanda
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany.
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5
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Polio and Its Epidemiology. Infect Dis (Lond) 2023. [DOI: 10.1007/978-1-0716-2463-0_839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
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Abstract
Kobuviruses are an unusual and poorly characterized genus within the picornavirus family and can cause gastrointestinal enteric disease in humans, livestock, and pets. The human kobuvirus Aichi virus (AiV) can cause severe gastroenteritis and deaths in children below the age of 5 years; however, this is a very rare occurrence. During the assembly of most picornaviruses (e.g., poliovirus, rhinovirus, and foot-and-mouth disease virus), the capsid precursor protein VP0 is cleaved into VP4 and VP2. However, kobuviruses retain an uncleaved VP0. From studies with other picornaviruses, it is known that VP4 performs the essential function of pore formation in membranes, which facilitates transfer of the viral genome across the endosomal membrane and into the cytoplasm for replication. Here, we employ genome exposure and membrane interaction assays to demonstrate that pH plays a critical role in AiV uncoating and membrane interactions. We demonstrate that incubation at low pH alters the exposure of hydrophobic residues within the capsid, enhances genome exposure, and enhances permeabilization of model membranes. Furthermore, using peptides we demonstrate that the N terminus of VP0 mediates membrane pore formation in model membranes, indicating that this plays an analogous function to VP4. IMPORTANCE To initiate infection, viruses must enter a host cell and deliver their genome into the appropriate location. The picornavirus family of small nonenveloped RNA viruses includes significant human and animal pathogens and is also a model to understand the process of cell entry. Most picornavirus capsids contain the internal protein VP4, generated from cleavage of a VP0 precursor. During entry, VP4 is released from the capsid. In enteroviruses this forms a membrane pore, which facilitates genome release into the cytoplasm. Due to high levels of sequence similarity, it is expected to play the same role for other picornaviruses. Some picornaviruses, such as Aichi virus, retain an intact VP0, and it is unknown how these viruses rearrange their capsids and induce membrane permeability in the absence of VP4. Here, we have used Aichi virus as a model VP0 virus to test for conservation of function between VP0 and VP4. This could enhance understanding of pore function and lead to development of novel therapeutic agents that block entry.
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Workie AB, Sefene EM. Ion-doped mesoporous bioactive glass: preparation, characterization, and applications using the spray pyrolysis method. RSC Adv 2022; 12:1592-1603. [PMID: 35425153 PMCID: PMC8979097 DOI: 10.1039/d1ra06113e] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 12/08/2021] [Indexed: 01/08/2023] Open
Abstract
Biotechnology is used extensively in medical procedures, dentistry, statures, biosensors, bio electrodes, skin substitutes, and medicine delivery systems. Glass is biocompatible and can be used in permanent implantation applications without risk. The porosity of BG matrixes, combined with their huge specific surface area, greatly aids the formation of hydroxyl carbonate apatite. Zn-Doped bioglass can be made in the lab in a variety of ways, depending on how it will be used in medical treatment. The melt-quenching technique, spray pyrolysis method, sol-gel process for BG fabrication, spray drying method, and modified Stöber method are examples of such strategies. Spray pyrolysis is a comprehensive approach that is an undeniably versatile and effective material synthesis technology. It is a low-cost, non-vacuum method for producing materials in the form of powders and films that may be deposited on a variety of substrates, and is a straightforward method to adapt for large-area deposition and industrial production processes. For better utility in medical care, MBG fabricated in the laboratory should be characterized using various characterization methods such as SEM, TEM, BET, and XRD.
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Affiliation(s)
- Andualem Belachew Workie
- Faculty of Mechanical and Industrial Engineering, Bahir Dar Institute of Technology, Bahir Dar University P.O. Box 26 Bahir Dar Ethiopia +251-910-894795 +251-918-161601
| | - Eyob Messele Sefene
- Faculty of Mechanical and Industrial Engineering, Bahir Dar Institute of Technology, Bahir Dar University P.O. Box 26 Bahir Dar Ethiopia +251-910-894795 +251-918-161601
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Sukeník L, Mukhamedova L, Procházková M, Škubník K, Plevka P, Vácha R. Cargo Release from Nonenveloped Viruses and Virus-like Nanoparticles: Capsid Rupture or Pore Formation. ACS NANO 2021; 15:19233-19243. [PMID: 34881874 DOI: 10.1021/acsnano.1c04814] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Virus-like nanoparticles are protein shells similar to wild-type viruses, and both aim to deliver their content into a cell. Unfortunately, the release mechanism of their cargo/genome remains elusive. Pores on the symmetry axes were proposed to enable the slow release of the viral genome. In contrast, cryo-EM images showed that capsids of nonenveloped RNA viruses can crack open and rapidly release the genome. We combined in vitro cryo-EM observations of the genome release of three viruses with coarse-grained simulations of generic virus-like nanoparticles to investigate the cargo/genome release pathways. Simulations provided details on both slow and rapid release pathways, including the success rates of individual releases. Moreover, the simulated structures from the rapid release pathway were in agreement with the experiment. Slow release occurred when interactions between capsid subunits were long-ranged, and the cargo/genome was noncompact. In contrast, rapid release was preferred when the interaction range was short and/or the cargo/genome was compact. These findings indicate a design strategy of virus-like nanoparticles for drug delivery.
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Affiliation(s)
- Lukáš Sukeník
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 267/2, 611 37 Brno, Czech Republic
| | - Liya Mukhamedova
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Michaela Procházková
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Karel Škubník
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Pavel Plevka
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Robert Vácha
- CEITEC - Central European Institute of Technology, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 267/2, 611 37 Brno, Czech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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9
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Nandi SS, Gohil T, Sawant SA, Lambe UP, Ghosh S, Jana S. CD155: A Key Receptor Playing Diversified Roles. Curr Mol Med 2021; 22:594-607. [PMID: 34514998 DOI: 10.2174/1566524021666210910112906] [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: 12/06/2020] [Revised: 06/16/2021] [Accepted: 06/20/2021] [Indexed: 11/22/2022]
Abstract
Cluster of differentiation (CD155), formerly identified as poliovirus receptor (PVR) and later as immunoglobulin molecule involved in cell adhesion, proliferation, invasion and migration. It is a surface protein expressed mostly on normal and transformed malignant cells. The expression of the receptor varies based on the origin of tissue. The expression of the protein is determined by factors involved in sonic hedgehog pathway, Ras-MEK-ERK pathway and during stress conditions like DNA damage response. The protein uses alternate splicing mechanism, producing four isoforms - two being soluble (CD155β and CD155γ) and two being transmembrane protein (CD155α and CD155δ). Apart from being a viral receptor, researchers have identified CD155 having important roles in cancer research and cell signaling field. The receptor is recognized as biomarker for identifying cancerous tissue. The receptor interacts with molecules involved in cells defense mechanism. The immune-surveillance role of CD155 is being deciphered to understand the mechanistic approach it utilizes as onco-immunologic molecule. CD155 is a non-MHC-I ligand which helps in identifying non-self to NK cells via an inhibitory TIGIT ligand. The TIGIT-CD155 pathway is a novel MHC-I-independent education mechanism for cell tolerance and activation of NK cell. The receptor also has a role in metastasis of cancer and trans endothelial mechanism. In this review, authors discuss the virus-host interaction that occurs via single transmembrane receptor, the poliovirus infection pathway, which is being exploited as therapeutic pathway. The oncolytic virotherapy is now promising way for curing cancer.
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Affiliation(s)
- Shyam Sundar Nandi
- National Institute of Virology, (Mumbai unit), (Formerly Enterovirus Research Centre). Haffkine Institute Compound, Indian Council of Medical Research, A. D. Marg, Parel. Mumbai-12. India
| | - Trupti Gohil
- National Institute of Virology, (Mumbai unit), (Formerly Enterovirus Research Centre). Haffkine Institute Compound, Indian Council of Medical Research, A. D. Marg, Parel. Mumbai-12. India
| | - Sonali Ankush Sawant
- National Institute of Virology, (Mumbai unit), (Formerly Enterovirus Research Centre). Haffkine Institute Compound, Indian Council of Medical Research, A. D. Marg, Parel. Mumbai-12. India
| | - Upendra Pradeep Lambe
- National Institute of Virology, (Mumbai unit), (Formerly Enterovirus Research Centre). Haffkine Institute Compound, Indian Council of Medical Research, A. D. Marg, Parel. Mumbai-12. India
| | - Sudip Ghosh
- Molecular Biology Division, ICMR-National Institute of Nutrition, Jamai-Osmania PO, Hyderabad. India
| | - Snehasis Jana
- Trivedi Science Research Laboratory Pvt Ltd., Thane-West, Maharashtra-400604. India
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10
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Current problems and future avenues in proteoliposome research. Biochem Soc Trans 2021; 48:1473-1492. [PMID: 32830854 DOI: 10.1042/bst20190966] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/11/2022]
Abstract
Membrane proteins (MPs) are the gatekeepers between different biological compartments separated by lipid bilayers. Being receptors, channels, transporters, or primary pumps, they fulfill a wide variety of cellular functions and their importance is reflected in the increasing number of drugs that target MPs. Functional studies of MPs within a native cellular context, however, is difficult due to the innate complexity of the densely packed membranes. Over the past decades, detergent-based extraction and purification of MPs and their reconstitution into lipid mimetic systems has been a very powerful tool to simplify the experimental system. In this review, we focus on proteoliposomes that have become an indispensable experimental system for enzymes with a vectorial function, including many of the here described energy transducing MPs. We first address long standing questions on the difficulty of successful reconstitution and controlled orientation of MPs into liposomes. A special emphasis is given on coreconstitution of several MPs into the same bilayer. Second, we discuss recent progress in the development of fluorescent dyes that offer sensitive detection with high temporal resolution. Finally, we briefly cover the use of giant unilamellar vesicles for the investigation of complex enzymatic cascades, a very promising experimental tool considering our increasing knowledge of the interplay of different cellular components.
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Jackson T, Belsham GJ. Picornaviruses: A View from 3A. Viruses 2021; 13:v13030456. [PMID: 33799649 PMCID: PMC7999760 DOI: 10.3390/v13030456] [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: 02/15/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 12/14/2022] Open
Abstract
Picornaviruses are comprised of a positive-sense RNA genome surrounded by a protein shell (or capsid). They are ubiquitous in vertebrates and cause a wide range of important human and animal diseases. The genome encodes a single large polyprotein that is processed to structural (capsid) and non-structural proteins. The non-structural proteins have key functions within the viral replication complex. Some, such as 3Dpol (the RNA dependent RNA polymerase) have conserved functions and participate directly in replicating the viral genome, whereas others, such as 3A, have accessory roles. The 3A proteins are highly divergent across the Picornaviridae and have specific roles both within and outside of the replication complex, which differ between the different genera. These roles include subverting host proteins to generate replication organelles and inhibition of cellular functions (such as protein secretion) to influence virus replication efficiency and the host response to infection. In addition, 3A proteins are associated with the determination of host range. However, recent observations have challenged some of the roles assigned to 3A and suggest that other viral proteins may carry them out. In this review, we revisit the roles of 3A in the picornavirus life cycle. The 3AB precursor and mature 3A have distinct functions during viral replication and, therefore, we have also included discussion of some of the roles assigned to 3AB.
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Affiliation(s)
- Terry Jackson
- The Pirbright Institute, Pirbright, Woking, Surrey GU24 0NF, UK;
| | - Graham J. Belsham
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark
- Correspondence:
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12
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Why Cells and Viruses Cannot Survive without an ESCRT. Cells 2021; 10:cells10030483. [PMID: 33668191 PMCID: PMC7995964 DOI: 10.3390/cells10030483] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 12/15/2022] Open
Abstract
Intracellular organelles enwrapped in membranes along with a complex network of vesicles trafficking in, out and inside the cellular environment are one of the main features of eukaryotic cells. Given their central role in cell life, compartmentalization and mechanisms allowing their maintenance despite continuous crosstalk among different organelles have been deeply investigated over the past years. Here, we review the multiple functions exerted by the endosomal sorting complex required for transport (ESCRT) machinery in driving membrane remodeling and fission, as well as in repairing physiological and pathological membrane damages. In this way, ESCRT machinery enables different fundamental cellular processes, such as cell cytokinesis, biogenesis of organelles and vesicles, maintenance of nuclear–cytoplasmic compartmentalization, endolysosomal activity. Furthermore, we discuss some examples of how viruses, as obligate intracellular parasites, have evolved to hijack the ESCRT machinery or part of it to execute/optimize their replication cycle/infection. A special emphasis is given to the herpes simplex virus type 1 (HSV-1) interaction with the ESCRT proteins, considering the peculiarities of this interplay and the need for HSV-1 to cross both the nuclear-cytoplasmic and the cytoplasmic-extracellular environment compartmentalization to egress from infected cells.
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Abstract
Genome transfer from a virus into a cell is a critical early step in viral replication. Enveloped viruses achieve the delivery of their genomes into the cytoplasm by merging the viral membrane with the cellular membrane via a conceptually simple mechanism called membrane fusion. In contrast, genome translocation mechanisms in nonenveloped viruses, which lack viral membranes, remain poorly understood. Although cellular assays provide useful information about cell entry and genome release, it is difficult to obtain detailed mechanistic insights due both to the inherent technical difficulties associated with direct visualization of these processes and to the prevalence of nonproductive events in cellular assays performed at a very high multiplicity of infection. To overcome these issues, we developed an in vitro single-particle fluorescence assay to characterize genome release from a nonenveloped virus (poliovirus) in real time using a tethered receptor-decorated liposome system. Our results suggest that poliovirus genome release is a complex process that consists of multiple rate-limiting steps. Interestingly, we found that the addition of exogenous wild-type capsid protein VP4, but not mutant VP4, enhanced the efficiency of genome translocation. These results, together with prior structural analysis, suggest that VP4 interacts with RNA directly and forms a protective, membrane-spanning channel during genome translocation. Furthermore, our data indicate that VP4 dynamically interacts with RNA, rather than forming a static tube for RNA translocation. This study provides new insights into poliovirus genome translocation and offers a cell-free assay that can be utilized broadly to investigate genome release processes in other nonenveloped viruses.
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14
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Abstract
Earlier analysis of the Protein Data Bank derived the distribution of rotations from the plane of a protein hydrogen bond donor peptide group to the plane of its acceptor peptide group. The quasi Boltzmann formalism of Pohl-Finkelstein is employed to estimate free energies of protein elements with these hydrogen bonds, pinpointing residues with a high propensity for conformational change. This is applied to viral glycoproteins as well as capsids, where the 90th+ percentiles of free energies determine residues that correlate well with viral fusion peptides and other functional domains in known cases and thus provide a novel method for predicting these sites of importance as antiviral drug or vaccine targets in general. The method is implemented at https://bion-server.au.dk/hbonds/ from an uploaded Protein Data Bank file.
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Affiliation(s)
- Robert C. Penner
- Institut des Hautes Études Scientifiques, Bures-sur-Yvette, France
- Mathematics Department, University of California at Los Angeles, Los Angeles, California
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15
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Shah PNM, Filman DJ, Karunatilaka KS, Hesketh EL, Groppelli E, Strauss M, Hogle JM. Cryo-EM structures reveal two distinct conformational states in a picornavirus cell entry intermediate. PLoS Pathog 2020; 16:e1008920. [PMID: 32997730 PMCID: PMC7549760 DOI: 10.1371/journal.ppat.1008920] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 10/12/2020] [Accepted: 08/21/2020] [Indexed: 12/18/2022] Open
Abstract
The virions of enteroviruses such as poliovirus undergo a global conformational change after binding to the cellular receptor, characterized by a 4% expansion, and by the opening of holes at the two and quasi-three-fold symmetry axes of the capsid. The resultant particle is called a 135S particle or A-particle and is thought to be on the pathway to a productive infection. Previously published studies have concluded that the membrane-interactive peptides, namely VP4 and the N-terminus of VP1, are irreversibly externalized in the 135S particle. However, using established protocols to produce the 135S particle, and single particle cryo-electron microscopy methods, we have identified at least two unique states that we call the early and late 135S particle. Surprisingly, only in the "late" 135S particles have detectable levels of the VP1 N-terminus been trapped outside the capsid. Moreover, we observe a distinct density inside the capsid that can be accounted for by VP4 that remains associated with the genome. Taken together our results conclusively demonstrate that the 135S particle is not a unique conformation, but rather a family of conformations that could exist simultaneously.
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Affiliation(s)
- Pranav N. M. Shah
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States of America
| | - David J. Filman
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States of America
| | - Krishanthi S. Karunatilaka
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States of America
| | - Emma L. Hesketh
- Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Elisabetta Groppelli
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Mike Strauss
- Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
| | - James M. Hogle
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, United States of America
- * E-mail:
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16
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Majer A, McGreevy A, Booth TF. Molecular Pathogenicity of Enteroviruses Causing Neurological Disease. Front Microbiol 2020; 11:540. [PMID: 32328043 PMCID: PMC7161091 DOI: 10.3389/fmicb.2020.00540] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/12/2020] [Indexed: 12/12/2022] Open
Abstract
Enteroviruses are single-stranded positive-sense RNA viruses that primarily cause self-limiting gastrointestinal or respiratory illness. In some cases, these viruses can invade the central nervous system, causing life-threatening neurological diseases including encephalitis, meningitis and acute flaccid paralysis (AFP). As we near the global eradication of poliovirus, formerly the major cause of AFP, the number of AFP cases have not diminished implying a non-poliovirus etiology. As the number of enteroviruses linked with neurological disease is expanding, of which many had previously little clinical significance, these viruses are becoming increasingly important to public health. Our current understanding of these non-polio enteroviruses is limited, especially with regards to their neurovirulence. Elucidating the molecular pathogenesis of these viruses is paramount for the development of effective therapeutic strategies. This review summarizes the clinical diseases associated with neurotropic enteroviruses and discusses recent advances in the understanding of viral invasion of the central nervous system, cell tropism and molecular pathogenesis as it correlates with host responses.
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Affiliation(s)
- Anna Majer
- Viral Diseases Division, National Microbiology Laboratory, Winnipeg, MB, Canada
| | - Alan McGreevy
- Viral Diseases Division, National Microbiology Laboratory, Winnipeg, MB, Canada.,Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada.,Department of Biology, University of Winnipeg, Winnipeg, MB, Canada
| | - Timothy F Booth
- Viral Diseases Division, National Microbiology Laboratory, Winnipeg, MB, Canada.,Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada
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17
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Liu Y, Guo L, Huang H, Dou J, Huang Q, Gan D, Chen J, Li Y, Zhang X, Wei Y. Facile preparation of magnetic composites based on carbon nanotubes: Utilization for removal of environmental pollutants. J Colloid Interface Sci 2019; 545:8-15. [DOI: 10.1016/j.jcis.2019.03.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 02/28/2019] [Accepted: 03/04/2019] [Indexed: 10/27/2022]
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18
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Zhao X, Zhang G, Liu S, Chen X, Peng R, Dai L, Qu X, Li S, Song H, Gao Z, Yuan P, Liu Z, Li C, Shang Z, Li Y, Zhang M, Qi J, Wang H, Du N, Wu Y, Bi Y, Gao S, Shi Y, Yan J, Zhang Y, Xie Z, Wei W, Gao GF. Human Neonatal Fc Receptor Is the Cellular Uncoating Receptor for Enterovirus B. Cell 2019; 177:1553-1565.e16. [PMID: 31104841 PMCID: PMC7111318 DOI: 10.1016/j.cell.2019.04.035] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 02/21/2019] [Accepted: 04/16/2019] [Indexed: 01/14/2023]
Abstract
Enterovirus B (EV-B), a major proportion of the genus Enterovirus in the family Picornaviridae, is the causative agent of severe human infectious diseases. Although cellular receptors for coxsackievirus B in EV-B have been identified, receptors mediating virus entry, especially the uncoating process of echovirus and other EV-B remain obscure. Here, we found that human neonatal Fc receptor (FcRn) is the uncoating receptor for major EV-B. FcRn binds to the virus particles in the "canyon" through its FCGRT subunit. By obtaining multiple cryo-electron microscopy structures at different stages of virus entry at atomic or near-atomic resolution, we deciphered the underlying mechanisms of enterovirus attachment and uncoating. These structures revealed that different from the attachment receptor CD55, binding of FcRn to the virions induces efficient release of "pocket factor" under acidic conditions and initiates the conformational changes in viral particle, providing a structural basis for understanding the mechanisms of enterovirus entry.
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Affiliation(s)
- Xin Zhao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China; CAS Center for Influenza Research and Early-Warning (CASCIRE), Chinese Academy of Sciences, 100101 Beijing, China
| | - Guigen Zhang
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, 100871 Beijing, China
| | - Sheng Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China; School of Life Sciences, University of Science and Technology of China, Hefei, 230026 Anhui, China
| | - Xiangpeng Chen
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Clinical Research Center for Respiratory Diseases, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Virology Laboratory, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, 100045 Beijing, China
| | - Ruchao Peng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Lianpan Dai
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, 100101 Beijing, China
| | - Xiao Qu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Shihua Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Hao Song
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, 100101 Beijing, China
| | - Zhengrong Gao
- KunMing Institute of Zoology, Chinese Academy of Sciences, 650223 KunMing, China
| | - Pengfei Yuan
- EdiGene Inc, Life Science Park, 22 KeXueYuan Road, Changping District, 102206 Beijing, China
| | - Zhiheng Liu
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, 100871 Beijing, China; Academy for Advanced Interdisciplinary Studies, Peking University, 100871 Beijing, China
| | - Changyao Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Zifang Shang
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, 100101 Beijing, China
| | - Yan Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Meifan Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Jianxun Qi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Han Wang
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, 100101 Beijing, China
| | - Ning Du
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, 100101 Beijing, China
| | - Yan Wu
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, 100101 Beijing, China
| | - Yuhai Bi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China; CAS Center for Influenza Research and Early-Warning (CASCIRE), Chinese Academy of Sciences, 100101 Beijing, China
| | - Shan Gao
- CAS Key Laboratory of Bio-medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, 215163 Suzhou, China
| | - Yi Shi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China; CAS Center for Influenza Research and Early-Warning (CASCIRE), Chinese Academy of Sciences, 100101 Beijing, China
| | - Jinghua Yan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China; CAS Center for Influenza Research and Early-Warning (CASCIRE), Chinese Academy of Sciences, 100101 Beijing, China; CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Yong Zhang
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), 102206 Beijing, China; WHO WPRO Regional Polio Reference Laboratory, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 102206 Beijing, China
| | - Zhengde Xie
- Key Laboratory of Major Diseases in Children, Ministry of Education, National Clinical Research Center for Respiratory Diseases, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Virology Laboratory, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, 100045 Beijing, China.
| | - Wensheng Wei
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, 100871 Beijing, China.
| | - George F Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China; CAS Center for Influenza Research and Early-Warning (CASCIRE), Chinese Academy of Sciences, 100101 Beijing, China; Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, 100101 Beijing, China; National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), 102206 Beijing, China; Savaid Medical School, University of Chinese Academy of Sciences, 100049 Beijing, China.
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19
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Anasir MI, Poh CL. Advances in Antigenic Peptide-Based Vaccine and Neutralizing Antibodies against Viruses Causing Hand, Foot, and Mouth Disease. Int J Mol Sci 2019; 20:ijms20061256. [PMID: 30871133 PMCID: PMC6471744 DOI: 10.3390/ijms20061256] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/01/2019] [Accepted: 03/02/2019] [Indexed: 12/13/2022] Open
Abstract
Hand, foot, and mouth disease (HFMD) commonly produces herpangina, but fatal neurological complications have been observed in children. Enterovirus 71 (EV-A71) and Coxsackievirus 16 (CV-A16) are the predominant viruses causing HFMD worldwide. With rising concern about HFMD outbreaks, there is a need for an effective vaccine against EV-A71 and CV-A16. Although an inactivated vaccine has been developed against EV-A71 in China, the inability of the inactivated vaccine to confer protection against CV-A16 infection and other HFMD etiological agents, such as CV-A6 and CV-A10, necessitates the exploration of other vaccine platforms. Thus, the antigenic peptide-based vaccines are promising platforms to develop safe and efficacious multivalent vaccines, while the monoclonal antibodies are viable therapeutic and prophylactic agents against HFMD etiological agents. This article reviews the available information related to the antigenic peptides of the etiological agents of HFMD and their neutralizing antibodies that can provide a basis for the design of future therapies against HFMD etiological agents.
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Affiliation(s)
- Mohd Ishtiaq Anasir
- Centre for Virus and Vaccine Research, Sunway University, Bandar Sunway, Subang Jaya, Selangor 47500, Malaysia.
| | - Chit Laa Poh
- Centre for Virus and Vaccine Research, Sunway University, Bandar Sunway, Subang Jaya, Selangor 47500, Malaysia.
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20
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Buchta D, Füzik T, Hrebík D, Levdansky Y, Sukeník L, Mukhamedova L, Moravcová J, Vácha R, Plevka P. Enterovirus particles expel capsid pentamers to enable genome release. Nat Commun 2019; 10:1138. [PMID: 30850609 PMCID: PMC6408523 DOI: 10.1038/s41467-019-09132-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 02/17/2019] [Indexed: 12/18/2022] Open
Abstract
Viruses from the genus Enterovirus are important human pathogens. Receptor binding or exposure to acidic pH in endosomes converts enterovirus particles to an activated state that is required for genome release. However, the mechanism of enterovirus uncoating is not well understood. Here, we use cryo-electron microscopy to visualize virions of human echovirus 18 in the process of genome release. We discover that the exit of the RNA from the particle of echovirus 18 results in a loss of one, two, or three adjacent capsid-protein pentamers. The opening in the capsid, which is more than 120 Å in diameter, enables the release of the genome without the need to unwind its putative double-stranded RNA segments. We also detect capsids lacking pentamers during genome release from echovirus 30. Thus, our findings uncover a mechanism of enterovirus genome release that could become target for antiviral drugs. Genome release of enteroviruses relies on exposure to acidic pH, but the mechanism of uncoating remains unclear. Here, Buchta et al. show that echovirus 18 loses one to three adjacent capsid-protein pentamers, resulting in an opening of more than 120 Å for genome release.
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Affiliation(s)
- David Buchta
- Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic
| | - Tibor Füzik
- Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic
| | - Dominik Hrebík
- Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic
| | - Yevgen Levdansky
- Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic.,Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076, Tübingen, Germany
| | - Lukáš Sukeník
- Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic.,Faculty of Science, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic
| | - Liya Mukhamedova
- Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic
| | - Jana Moravcová
- Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic
| | - Robert Vácha
- Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic.,Faculty of Science, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic
| | - Pavel Plevka
- Central European Institute of Technology, Masaryk University, Kamenice 5, Brno, 625 00, Czech Republic.
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21
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Ross CJ, Atilgan AR, Tastan Bishop Ö, Atilgan C. Unraveling the Motions behind Enterovirus 71 Uncoating. Biophys J 2019; 114:822-838. [PMID: 29490244 DOI: 10.1016/j.bpj.2017.12.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/10/2017] [Accepted: 12/12/2017] [Indexed: 01/24/2023] Open
Abstract
Enterovirus 71 can be a severe pathogen in small children and immunocompromised adults. Virus uncoating is a critical step in the infection of the host cell; however, the mechanisms that control this process remain poorly understood. We applied normal mode analysis and perturbation response scanning to several complexes of the virus capsid and present a coarse-graining approach to analyze the full capsid. We show that our method offers an alternative to expressing the system as a set of rigid blocks and accounts for the interconnection between nodes within each subunit and protein interfaces across the capsid. In our coarse-grained approach, the modes associated with capsid expansion are captured in the first three nondegenerate modes and correspond to the changes observed in structural studies of the virus. We show that the resolution of the analysis may be modified without losing information on the global motions leading to uncoating. Perturbation response scanning revealed that a protomer cannot serve as a functional unit to explain deformations of the capsid. Instead, we define a pentamer as the minimum functional unit to investigate changes within the capsid. From the modal analysis and perturbation response scanning, we locate a hotspot region surrounding the fivefold axis. The range of the effect of these single, hotspot residues extend to 140 Å. The perturbation of internal capsid residues in this region displayed greatest propensity to capsid expansion, thus indicating the significant role that the RNA genome may play in triggering uncoating.
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Affiliation(s)
- Caroline J Ross
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa
| | - Ali Rana Atilgan
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa
| | - Canan Atilgan
- Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey.
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22
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Lehrer S, Rheinstein PH. Inverse Relationship Between Polio Incidence in the US and Colorectal Cancer. In Vivo 2019; 32:1485-1489. [PMID: 30348706 DOI: 10.21873/invivo.11404] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 09/20/2018] [Accepted: 09/28/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND/AIM Polio is predominantly an enteric viral infection that was progressively eradicated in the United States after the introduction of polio vaccine in the early 1950s. U.S. colorectal cancer rates have dropped steadily for individuals born between 1890 and 1950, but have been increasing for every generation born since 1950. Moreover, the lowest worldwide age adjusted rates of colorectal cancer in 2012 were in sub-Saharan Africa, Gambia and Mozambique, where polio has not been eradicated. In the current study, poliomyelitis incidence in US states before the introduction of polio vaccine was analyzed. MATERIALS AND METHODS Reported cases of poliomyelitis per 100,000 population by state 1932-1951 were from Centers for Disease Control. Colorectal cancer deaths per 100,000 in men (2005-2009) by US State are from the American Cancer Society. US state overweight and obesity data are from the Centers for Disease Control and Prevention (CDC). Smoking data are from the CDC. RESULTS By US state, colorectal cancer incidence per 100,000 in men for 2005-2009 was inversely correlated with reported cases of poliomyelitis per 100,000 for 1932-1951 (r=-0.311, p=0.032). Colorectal cancer deaths per 100,000 in men in 2005-2009 were also inversely correlated with reported cases of poliomyelitis per 100,000 by state for 1932-1951 (r=-0.493, p<0.001). The relationship between colorectal cancer deaths and polio incidence was significant (β=-0.196, p=0.028) and independent of the effects of smoking (β=0.289, p=0.012) and overweight (β=0.547, p<0.001). The relationship in females with colorectal cancer was identical. CONCLUSION Polio virus infection of cells of the colon may induce some degree of resistance to the development of colon cancer decades later. The effect of polio virus infection seems to be especially potent in reducing the rate of death from colon cancer.
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Affiliation(s)
- Steven Lehrer
- Department of Radiation Oncology, Icahn School of Medicine at Mount Sinai, New York, U.S.A.
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23
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Molecular basis for the acid-initiated uncoating of human enterovirus D68. Proc Natl Acad Sci U S A 2018; 115:E12209-E12217. [PMID: 30530701 DOI: 10.1073/pnas.1803347115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Enterovirus D68 (EV-D68) belongs to a group of enteroviruses that contain a single positive-sense RNA genome surrounded by an icosahedral capsid. Like common cold viruses, EV-D68 mainly causes respiratory infections and is acid-labile. The molecular mechanism by which the acid-sensitive EV-D68 virions uncoat and deliver their genome into a host cell is unknown. Using cryoelectron microscopy (cryo-EM), we have determined the structures of the full native virion and an uncoating intermediate [the A (altered) particle] of EV-D68 at 2.2- and 2.7-Å resolution, respectively. These structures showed that acid treatment of EV-D68 leads to particle expansion, externalization of the viral protein VP1 N termini from the capsid interior, and formation of pores around the icosahedral twofold axes through which the viral RNA can exit. Moreover, because of the low stability of EV-D68, cryo-EM analyses of a mixed population of particles at neutral pH and following acid treatment demonstrated the involvement of multiple structural intermediates during virus uncoating. Among these, a previously undescribed state, the expanded 1 ("E1") particle, shows a majority of internal regions (e.g., the VP1 N termini) to be ordered as in the full native virion. Thus, the E1 particle acts as an intermediate in the transition from full native virions to A particles. Together, the present work delineates the pathway of EV-D68 uncoating and provides the molecular basis for the acid lability of EV-D68 and of the related common cold viruses.
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24
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Chia MY, Chung WY, Wang CH, Chang WH, Lee MS. Development of a high-growth enterovirus 71 vaccine candidate inducing cross-reactive neutralizing antibody responses. Vaccine 2018; 36:1167-1173. [PMID: 29398272 DOI: 10.1016/j.vaccine.2018.01.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 01/03/2018] [Accepted: 01/16/2018] [Indexed: 02/04/2023]
Abstract
Although Enterovirus 71 (EV71) has only one serotype based on serum neutralization tests using hyperimmune animal antisera, three major genogroups (A, B and C) including eleven genotypes (A, B1-B2, and C1-C5) can be well classified based on phylogenetic analysis. Since 1997, large-scale EV71 epidemics occurred cyclically with different genotypes in the Asia-Pacific region. Therefore, development of EV71 vaccines is a national priority in several Asian countries. Currently, five vaccine candidates have been evaluated in clinical trials in China (three C4 candidates), Singapore (one B2 candidate), and Taiwan (one B4 candidate). Overall, the peak viral titers of these 5 vaccine candidates could only reach about 107 TCID50/mL. Moreover, genotypes of these 5 candidates are different from the current predominant genotype B5 in Taiwan and South-Eastern Asia. We adapted a high-growth EV71 genotype B5 (HG-B5) virus after multiple passages and plaque selections in Vero cells and the HG-B5 virus could reach high titers (>108 TCID50/mL) in a microcarrier-based cell culture system. The viral particles were further purified and formulated with alum adjuvant. After two doses of intramuscular immunization in rabbits, the HG-B5 vaccine candidate could induce cross-reactive neutralizing antibodies against the three major EV71 genogroups. In conclusion, a high-growth EV71 virus was successfully adapted in Vero cells and could induce broad spectrum neutralizing antibody titers against three (A, B5, and C4) genotypes in rabbits.
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Affiliation(s)
- Min-Yuan Chia
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan; Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Wan-Yu Chung
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | | | - Wei-Hau Chang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
| | - Min-Shi Lee
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan.
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25
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N-Terminal Myristoylated VP5 is Required for Penetrating Cell Membrane and Promoting Infectivity in Aquareoviruses. Virol Sin 2018; 33:287-290. [PMID: 29869748 DOI: 10.1007/s12250-018-0036-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/10/2018] [Indexed: 10/14/2022] Open
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26
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Fibronectin Facilitates Enterovirus 71 Infection by Mediating Viral Entry. J Virol 2018; 92:JVI.02251-17. [PMID: 29467312 DOI: 10.1128/jvi.02251-17] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 02/13/2018] [Indexed: 11/20/2022] Open
Abstract
Fibronectin (FN) is a high-molecular-weight extracellular matrix protein that contains the RGDS motif, which is required to bind to integrins. Synthetic RGDS peptides have been reported to compete with FN to bind to the cell surface and inhibit the function of FN. Here, we identified that synthetic RGDS peptides significantly inhibit human enterovirus 71 (EV71) infection in cell cultures. In addition, mice treated with RGDS peptides and infected with EV71 had a significantly higher survival rate and a lower viral load than the control group. Because RGDS peptides affect the function of FN, we questioned whether FN may play a role in virus infection. Our study indicates that overexpression of FN enhanced EV71 infection. In contrast, knockout of FN significantly reduced viral yield and decreased the viral binding to host cells. Furthermore, EV71 entry, rather than intracellular viral replication, was blocked by FN inhibitor pretreatment. Next, we found that FN could interact with the EV71 capsid protein VP1, and further truncated-mutation assays indicated that the D2 domain of FN could interact with the N-terminal fragment of VP1. Taken together, our results demonstrate that the host factor FN binds to EV71 particles and facilitates EV71 entry, providing a potential therapy target for EV71 infection.IMPORTANCE Hand, foot, and mouth disease outbreaks have occurred frequently in recent years, sometimes causing severe neurological complications and even death in infants and young children worldwide. Unfortunately, no effective antiviral drugs are available for human enterovirus 71 (EV71), one of the viruses that cause hand, foot, and mouth disease. The infection process and the host factors involved remain unknown, although several receptors have been identified. In this study, we found that the host factor fibronectin (FN) facilitated EV71 replication by interacting with EV71 particles and further mediated their entry. The RGDS peptide, an FN inhibitor, significantly inhibited EV71 replication in both RD cells and mice. In conclusion, our research identified a new host factor involved in EV71 infection, providing a new potential antiviral target for EV71 treatment.
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Cleavage of the C-Terminal Fragment of Reovirus μ1 Is Required for Optimal Infectivity. J Virol 2018; 92:JVI.01848-17. [PMID: 29298891 DOI: 10.1128/jvi.01848-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 12/20/2017] [Indexed: 12/12/2022] Open
Abstract
The mammalian orthoreovirus (reovirus) outer capsid, which is composed of 200 μ1/σ3 heterohexamers and a maximum of 12 σ1 trimers, contains all of the proteins that are necessary for attaching to and entering host cells. Following attachment, reovirus is internalized by receptor-mediated endocytosis and acid-dependent cathepsin proteases degrade the σ3 protein. This process generates a metastable intermediate, called infectious subviral particle (ISVP), in which the μ1 membrane penetration protein is exposed. ISVPs undergo a second structural rearrangement to deposit the genome-containing core into the host cytoplasm. The conformationally altered particle is called ISVP*. ISVP-to-ISVP* conversion culminates in the release of μ1 N- and C-terminal fragments, μ1N and Φ, respectively. Released μ1N is thought to facilitate core delivery by generating size-selective pores within the endosomal membrane, whereas the precise role of Φ, particularly in the context of viral entry, is undefined. In this report, we characterize a recombinant reovirus that fails to cleave Φ from μ1 in vitro Φ cleavage, which is not required for ISVP-to-ISVP* conversion, enhances the disruption of liposomal membranes and facilitates the recruitment of ISVP*s to the site of pore formation. Moreover, the Φ cleavage-deficient strain initiates infection of host cells less efficiently than the parental strain. These results indicate that μ1N and Φ contribute to reovirus pore forming activity.IMPORTANCE Host membranes represent a physical barrier that prevents infection. To overcome this barrier, viruses utilize diverse strategies, such as membrane fusion or membrane disruption, to access internal components of the cell. These strategies are characterized by discrete protein-protein and protein-lipid interactions. The mammalian orthoreovirus (reovirus) outer capsid undergoes a series of well-defined conformational changes, which conclude with pore formation and delivery of the viral genetic material. In this report, we characterize the role of the small, reovirus-derived Φ peptide in pore formation. Φ cleavage from the outer capsid enhances membrane disruption and facilitates the recruitment of virions to membrane-associated pores. Moreover, Φ cleavage promotes the initiation of infection. Together, these results reveal an additional component of the reovirus pore forming apparatus and highlight a strategy for penetrating host membranes.
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Abstract
Recently, dozens of virus structures have been solved to resolutions between 2.5 and 5.0 Å by means of electron cryomicroscopy. With these structures we are now firmly within the "atomic age" of electron cryomicroscopy, as these studies can reveal atomic details of protein and nucleic acid topology and interactions between specific residues. This improvement in resolution has been the result of direct electron detectors and image processing advances. Although enforcing symmetry facilitates reaching near-atomic resolution with fewer particle images, it unfortunately obscures some biologically interesting components of a virus. New approaches on relaxing symmetry and exploring structure dynamics and heterogeneity of viral assemblies have revealed important insights into genome packaging, virion assembly, cell entry, and other stages of the viral life cycle. In the future, novel methods will be required to reveal yet-unknown structural conformations of viruses, relevant to their biological activities. Ultimately, these results hold the promise of answering many unresolved questions linking structural diversity of viruses to their biological functions.
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Affiliation(s)
- Jason T Kaelber
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030.,National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Corey F Hryc
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.,Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030;
| | - Wah Chiu
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030.,National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.,Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030;
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Fang PY, Gómez Ramos L, Holguin SY, Hsiao C, Bowman JC, Yang HW, Williams LD. Functional RNAs: combined assembly and packaging in VLPs. Nucleic Acids Res 2017; 45:3519-3527. [PMID: 27903913 PMCID: PMC5399791 DOI: 10.1093/nar/gkw1154] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 10/24/2016] [Accepted: 11/21/2016] [Indexed: 01/09/2023] Open
Abstract
We describe here a one pot RNA production, packaging and delivery system based on bacteriophage Qβ. We demonstrate a method for production of a novel RNAi scaffold, packaged within Qβ virus-like particles (VLPs). The RNAi scaffold is a general utility chimera that contains a functional RNA duplex with paired silencing and carrier sequences stabilized by a miR-30 stem-loop. The Qβ hairpin on the 5΄ end confers affinity for the Qβ coat protein (CP). Silencing sequences can include mature miRNAs and siRNAs, and can target essentially any desired mRNA. The VLP-RNAi assembles upon co-expression of CP and the RNAi scaffold in E. coli. The annealing of the scaffold to form functional RNAs is intramolecular and is therefore robust and concentration independent. We demonstrate dose- and time-dependent inhibition of GFP expression in human cells with VLP-RNAi. In addition, we target the 3΄UTR of oncogenic Ras mRNA and suppress Pan-Ras expression, which attenuates cell proliferation and promotes mortality of brain tumor cells. This combination of RNAi scaffold design with Qβ VLP packaging is demonstrated to be target-specific and efficient.
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Affiliation(s)
- Po-Yu Fang
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Lizzette M. Gómez Ramos
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Stefany Y. Holguin
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Chiaolong Hsiao
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, Republic of China
| | - Jessica C. Bowman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hung-Wei Yang
- Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Loren Dean Williams
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
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Groppelli E, Levy HC, Sun E, Strauss M, Nicol C, Gold S, Zhuang X, Tuthill TJ, Hogle JM, Rowlands DJ. Picornavirus RNA is protected from cleavage by ribonuclease during virion uncoating and transfer across cellular and model membranes. PLoS Pathog 2017; 13:e1006197. [PMID: 28166307 PMCID: PMC5325612 DOI: 10.1371/journal.ppat.1006197] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 02/24/2017] [Accepted: 01/22/2017] [Indexed: 12/04/2022] Open
Abstract
Picornaviruses are non-enveloped RNA viruses that enter cells via receptor-mediated endocytosis. Because they lack an envelope, picornaviruses face the challenge of delivering their RNA genomes across the membrane of the endocytic vesicle into the cytoplasm to initiate infection. Currently, the mechanism of genome release and translocation across membranes remains poorly understood. Within the enterovirus genus, poliovirus, rhinovirus 2, and rhinovirus 16 have been proposed to release their genomes across intact endosomal membranes through virally induced pores, whereas one study has proposed that rhinovirus 14 releases its RNA following disruption of endosomal membranes. For the more distantly related aphthovirus genus (e.g. foot-and-mouth disease viruses and equine rhinitis A virus) acidification of endosomes results in the disassembly of the virion into pentamers and in the release of the viral RNA into the lumen of the endosome, but no details have been elucidated as how the RNA crosses the vesicle membrane. However, more recent studies suggest aphthovirus RNA is released from intact particles and the dissociation to pentamers may be a late event. In this study we have investigated the RNase A sensitivity of genome translocation of poliovirus using a receptor-decorated-liposome model and the sensitivity of infection of poliovirus and equine-rhinitis A virus to co-internalized RNase A. We show that poliovirus genome translocation is insensitive to RNase A and results in little or no release into the medium in the liposome model. We also show that infectivity is not reduced by co-internalized RNase A for poliovirus and equine rhinitis A virus. Additionally, we show that all poliovirus genomes that are internalized into cells, not just those resulting in infection, are protected from RNase A. These results support a finely coordinated, directional model of viral RNA delivery that involves viral proteins and cellular membranes. Picornaviruses are a large family of important human and animal pathogens that include poliovirus, human rhinovirus and foot-and-mouth disease virus. Picornaviruses enter the host cell by hijacking one of the vesicle-mediated cellular entry routes. However, once the virus is internalized, the mechanism used to deliver the viral genome across the vesicle membrane and into the cytoplasm remains unclear and even controversial. Here we show that for poliovirus (a member of the enterovirus genus), viral RNA is translocated directly from the particle, across the vesicle membrane into the lumen of liposomes in a receptor-decorated liposome model, or cytoplasm during infection, without being exposed to external medium surrounding the liposomes or the lumen of the entry vesicle, respectively. Our results suggest that the interaction between the viral particle and the membrane results in a specific mechanism of viral genome delivery that not only directs but also protects the RNA so that it reaches the cytoplasm as an intact and functional molecule. Additionally, we show that this is also the case for equine rhinitis A virus, a member of the aphthovirus genus, whose genome delivery mechanism has previously been thought to differ significantly from the mechanism used by enteroviruses suggesting the possibility of a unified mechanism of RNA delivery for the entire picornavirus family.
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Affiliation(s)
- Elisabetta Groppelli
- School of Molecular and Cellular Biology & Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, West Yorkshire, United Kingdom
| | - Hazel C. Levy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Eileen Sun
- Program in Virology and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Mike Strauss
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Clare Nicol
- School of Molecular and Cellular Biology & Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, West Yorkshire, United Kingdom
| | - Sarah Gold
- The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Xiaowei Zhuang
- Howard Hughes Institute and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | | | - James M. Hogle
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (JMH); (DJR)
| | - David J. Rowlands
- School of Molecular and Cellular Biology & Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, West Yorkshire, United Kingdom
- * E-mail: (JMH); (DJR)
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31
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Delgui LR, Colombo MI. A Novel Mechanism Underlying the Innate Immune Response Induction upon Viral-Dependent Replication of Host Cell mRNA: A Mistake of +sRNA Viruses' Replicases. Front Cell Infect Microbiol 2017; 7:5. [PMID: 28164038 PMCID: PMC5247633 DOI: 10.3389/fcimb.2017.00005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 01/04/2017] [Indexed: 12/25/2022] Open
Abstract
Viruses are lifeless particles designed for setting virus-host interactome assuring a new generation of virions for dissemination. This interactome generates a pressure on host organisms evolving mechanisms to neutralize viral infection, which places the pressure back onto virus, a process known as virus-host cell co-evolution. Positive-single stranded RNA (+sRNA) viruses are an important group of viral agents illustrating this interesting phenomenon. During replication, their genomic +sRNA is employed as template for translation of viral proteins; among them the RNA-dependent RNA polymerase (RdRp) is responsible of viral genome replication originating double-strand RNA molecules (dsRNA) as intermediates, which accumulate representing a potent threat for cellular dsRNA receptors to initiate an antiviral response. A common feature shared by these viruses is their ability to rearrange cellular membranes to serve as platforms for genome replication and assembly of new virions, supporting replication efficiency increase by concentrating critical factors and protecting the viral genome from host anti-viral systems. This review summarizes current knowledge regarding cellular dsRNA receptors and describes prototype viruses developing replication niches inside rearranged membranes. However, for several viral agents it's been observed both, a complex rearrangement of cellular membranes and a strong innate immune antiviral response induction. So, we have included recent data explaining the mechanism by, even though viruses have evolved elegant hideouts, host cells are still able to develop dsRNA receptors-dependent antiviral response.
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Affiliation(s)
- Laura R Delgui
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Facultad de Ciencias Médicas, Instituto de Histología y Embriología de Mendoza, Universidad Nacional de CuyoMendoza, Argentina; Facultad de Ciencias Exactas y Naturales, Universidad Nacional de CuyoMendoza, Argentina
| | - María I Colombo
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Facultad de Ciencias Médicas, Instituto de Histología y Embriología de Mendoza, Universidad Nacional de Cuyo Mendoza, Argentina
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32
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Cryo-electron Microscopy Structures of Expanded Poliovirus with VHHs Sample the Conformational Repertoire of the Expanded State. J Virol 2017; 91:JVI.01443-16. [PMID: 27852863 DOI: 10.1128/jvi.01443-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 10/26/2016] [Indexed: 01/14/2023] Open
Abstract
By using cryo-electron microscopy, expanded 80S-like poliovirus virions (poliovirions) were visualized in complexes with four 80S-specific camelid VHHs (Nanobodies). In all four complexes, the VHHs bind to a site on the top surface of the capsid protein VP3, which is hidden in the native virus. Interestingly, although the four VHHs bind to the same site, the structures of the expanded virus differ in detail in each complex, suggesting that each of the Nanobodies has sampled a range of low-energy structures available to the expanded virion. By stabilizing unique structures of expanded virions, VHH binding permitted a more detailed view of the virus structure than was previously possible, leading to a better understanding of the expansion process that is a critical step in infection. It is now clear which polypeptide chains become disordered and which become rearranged. The higher resolution of these structures also revealed well-ordered conformations for the EF loop of VP2, the GH loop of VP3, and the N-terminal extensions of VP1 and VP2, which, in retrospect, were present in lower-resolution structures but not recognized. These structural observations help to explain preexisting mutational data and provide insights into several other stages of the poliovirus life cycle, including the mechanism of receptor-triggered virus expansion. IMPORTANCE When poliovirus infects a cell, it undergoes a change in its structure in order to pass RNA through its protein coat, but this altered state is short-lived and thus poorly understood. The structures of poliovirus bound to single-domain antibodies presented here capture the altered virus in what appear to be intermediate states. A careful analysis of these structures lets us better understand the molecular mechanism of infection and how these changes in the virus lead to productive-infection events.
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33
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Cryo-EM study of slow bee paralysis virus at low pH reveals iflavirus genome release mechanism. Proc Natl Acad Sci U S A 2017; 114:598-603. [PMID: 28053231 DOI: 10.1073/pnas.1616562114] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Viruses from the family Iflaviridae are insect pathogens. Many of them, including slow bee paralysis virus (SBPV), cause lethal diseases in honeybees and bumblebees, resulting in agricultural losses. Iflaviruses have nonenveloped icosahedral virions containing single-stranded RNA genomes. However, their genome release mechanism is unknown. Here, we show that low pH promotes SBPV genome release, indicating that the virus may use endosomes to enter host cells. We used cryo-EM to study a heterogeneous population of SBPV virions at pH 5.5. We determined the structures of SBPV particles before and after genome release to resolutions of 3.3 and 3.4 Å, respectively. The capsids of SBPV virions in low pH are not expanded. Thus, SBPV does not appear to form "altered" particles with pores in their capsids before genome release, as is the case in many related picornaviruses. The egress of the genome from SBPV virions is associated with a loss of interpentamer contacts mediated by N-terminal arms of VP2 capsid proteins, which result in the expansion of the capsid. Pores that are 7 Å in diameter form around icosahedral threefold symmetry axes. We speculate that they serve as channels for the genome release. Our findings provide an atomic-level characterization of the genome release mechanism of iflaviruses.
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34
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Nasr ML, Baptista D, Strauss M, Sun ZYJ, Grigoriu S, Huser S, Plückthun A, Hagn F, Walz T, Hogle JM, Wagner G. Covalently circularized nanodiscs for studying membrane proteins and viral entry. Nat Methods 2016; 14:49-52. [PMID: 27869813 DOI: 10.1038/nmeth.4079] [Citation(s) in RCA: 194] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 10/19/2016] [Indexed: 12/22/2022]
Abstract
We engineered covalently circularized nanodiscs (cNDs) which, compared with standard nanodiscs, exhibit enhanced stability, defined diameter sizes and tunable shapes. Reconstitution into cNDs enhanced the quality of nuclear magnetic resonance spectra for both VDAC-1, a β-barrel membrane protein, and the G-protein-coupled receptor NTR1, an α-helical membrane protein. In addition, we used cNDs to visualize how simple, nonenveloped viruses translocate their genomes across membranes to initiate infection.
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Affiliation(s)
- Mahmoud L Nasr
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Diego Baptista
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Mike Strauss
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Zhen-Yu J Sun
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Simina Grigoriu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Sonja Huser
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Franz Hagn
- Department of Chemistry and Institute for Advanced Study, Technische Universität München and Helmholtz Centre Munich, Munich, Germany
| | - Thomas Walz
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - James M Hogle
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
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Panjwani A, Asfor AS, Tuthill TJ. The conserved N-terminus of human rhinovirus capsid protein VP4 contains membrane pore-forming activity and is a target for neutralizing antibodies. J Gen Virol 2016; 97:3238-3242. [PMID: 27902347 PMCID: PMC5203672 DOI: 10.1099/jgv.0.000629] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Human rhinovirus is the causative agent of the common cold and belongs to the non-enveloped picornavirus family. A trigger such as receptor binding or low pH initiates conformational changes in the capsid that allow the virus to attach to membranes and form a pore for the translocation of viral RNA into the cytoplasm. We previously showed that recombinant capsid protein VP4 was able to form membrane pores. In this study, we show the N-terminus but not C-terminus of VP4 formed pores with properties similar to full-length VP4 and consistent with the size required for transfer of RNA. Sera against the N-terminus but not C-terminus of VP4 were shown to neutralize virus infectivity. Together, this suggests that the N-terminus of VP4 is responsible for membrane activity. This study contributes to an improved understanding of the mechanisms for involvement of VP4 in entry and its potential as an antiviral target.
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Affiliation(s)
- Anusha Panjwani
- The Pirbright Institute, Ash Road, Pirbright, Woking GU24 0NF, UK
| | - Amin S Asfor
- The Pirbright Institute, Ash Road, Pirbright, Woking GU24 0NF, UK
| | - Tobias J Tuthill
- The Pirbright Institute, Ash Road, Pirbright, Woking GU24 0NF, UK
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Rolfsson Ó, Middleton S, Manfield IW, White SJ, Fan B, Vaughan R, Ranson NA, Dykeman E, Twarock R, Ford J, Kao CC, Stockley PG. Direct Evidence for Packaging Signal-Mediated Assembly of Bacteriophage MS2. J Mol Biol 2016; 428:431-48. [PMID: 26608810 PMCID: PMC4751978 DOI: 10.1016/j.jmb.2015.11.014] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 11/06/2015] [Accepted: 11/08/2015] [Indexed: 01/20/2023]
Abstract
Using cross-linking coupled to matrix-assisted laser desorption/ionization mass spectrometry and CLIP-Seq sequencing, we determined the peptide and oligonucleotide sequences at the interfaces between the capsid proteins and the genomic RNA of bacteriophage MS2. The results suggest that the same coat protein (CP)-RNA and maturation protein (MP)-RNA interfaces are used in every viral particle. The portions of the viral RNA in contact with CP subunits span the genome, consistent with a large number of discrete and similar contacts within each particle. Many of these sites match previous predictions of the locations of multiple, dispersed and degenerate RNA sites with cognate CP affinity termed packaging signals (PSs). Chemical RNA footprinting was used to compare the secondary structures of protein-free genomic fragments and the RNA in the virion. Some PSs are partially present in protein-free RNA but others would need to refold from their dominant solution conformations to form the contacts identified in the virion. The RNA-binding peptides within the MP map to two sections of the N-terminal half of the protein. Comparison of MP sequences from related phages suggests a similar arrangement of RNA-binding sites, although these N-terminal regions have only limited sequence conservation. In contrast, the sequences of the C-termini are highly conserved, consistent with them encompassing pilin-binding domains required for initial contact with host cells. These results provide independent and unambiguous support for the assembly of MS2 virions via a PS-mediated mechanism involving a series of induced-fit viral protein interactions with RNA.
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Affiliation(s)
- Óttar Rolfsson
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Stefani Middleton
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA; The Center for Genomics and Bioinformatics, Indiana University, Bloomington, IN 47405, USA
| | - Iain W Manfield
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Simon J White
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Baochang Fan
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Robert Vaughan
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Neil A Ranson
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Eric Dykeman
- Department of Biology and Mathematics and York Centre for Complex Systems Analysis, University of York, York YO10 5DD, United Kingdom
| | - Reidun Twarock
- Department of Biology and Mathematics and York Centre for Complex Systems Analysis, University of York, York YO10 5DD, United Kingdom
| | - James Ford
- The Center for Genomics and Bioinformatics, Indiana University, Bloomington, IN 47405, USA
| | - C Cheng Kao
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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Rossignol ED, Yang JE, Bullitt E. The Role of Electron Microscopy in Studying the Continuum of Changes in Membranous Structures during Poliovirus Infection. Viruses 2015; 7:5305-18. [PMID: 26473912 PMCID: PMC4632382 DOI: 10.3390/v7102874] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/01/2015] [Accepted: 09/23/2015] [Indexed: 12/26/2022] Open
Abstract
Replication of the poliovirus genome is localized to cytoplasmic replication factories that are fashioned out of a mixture of viral proteins, scavenged cellular components, and new components that are synthesized within the cell due to viral manipulation/up-regulation of protein and phospholipid synthesis. These membranous replication factories are quite complex, and include markers from multiple cytoplasmic cellular organelles. This review focuses on the role of electron microscopy in advancing our understanding of poliovirus RNA replication factories. Structural data from the literature provide the basis for interpreting a wide range of biochemical studies that have been published on virus-induced lipid biosynthesis. In combination, structural and biochemical experiments elucidate the dramatic membrane remodeling that is a hallmark of poliovirus infection. Temporal and spatial membrane modifications throughout the infection cycle are discussed. Early electron microscopy studies of morphological changes following viral infection are re-considered in light of more recent data on viral manipulation of lipid and protein biosynthesis. These data suggest the existence of distinct subcellular vesicle populations, each of which serves specialized roles in poliovirus replication processes.
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Affiliation(s)
- Evan D Rossignol
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, W302, Boston, MA 02118-2526, USA.
| | - Jie E Yang
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, W302, Boston, MA 02118-2526, USA.
| | - Esther Bullitt
- Department of Physiology & Biophysics, Boston University School of Medicine, 700 Albany Street, W302, Boston, MA 02118-2526, USA.
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38
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Nectin-like interactions between poliovirus and its receptor trigger conformational changes associated with cell entry. J Virol 2015; 89:4143-57. [PMID: 25631086 DOI: 10.1128/jvi.03101-14] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED Poliovirus infection is initiated by attachment to a receptor on the cell surface called Pvr or CD155. At physiological temperatures, the receptor catalyzes an irreversible expansion of the virus to form an expanded form of the capsid called the 135S particle. This expansion results in the externalization of the myristoylated capsid protein VP4 and the N-terminal extension of the capsid protein VP1, both of which become inserted into the cell membrane. Structures of the expanded forms of poliovirus and of several related viruses have recently been reported. However, until now, it has been unclear how receptor binding triggers viral expansion at physiological temperature. Here, we report poliovirus in complex with an enzymatically partially deglycosylated form of the 3-domain ectodomain of Pvr at a 4-Å resolution, as determined by cryo-electron microscopy. The interaction of the receptor with the virus in this structure is reminiscent of the interactions of Pvr with its natural ligands. At a low temperature, the receptor induces very few changes in the structure of the virus, with the largest changes occurring within the footprint of the receptor, and in a loop of the internal protein VP4. Changes in the vicinity of the receptor include the displacement of a natural lipid ligand (called "pocket factor"), demonstrating that the loss of this ligand, alone, is not sufficient to induce particle expansion. Finally, analogies with naturally occurring ligand binding in the nectin family suggest which specific structural rearrangements in the virus-receptor complex could help to trigger the irreversible expansion of the capsid. IMPORTANCE The cell-surface receptor (Pvr) catalyzes a large structural change in the virus that exposes membrane-binding protein chains. We fitted known atomic models of the virus and Pvr into three-dimensional experimental maps of the receptor-virus complex. The molecular interactions we see between poliovirus and its receptor are reminiscent of the nectin family, by involving the burying of otherwise-exposed hydrophobic groups. Importantly, poliovirus expansion is regulated by the binding of a lipid molecule within the viral capsid. We show that receptor binding either causes this molecule to be expelled or requires it, but that its loss is not sufficient to trigger irreversible expansion. Based on our model, we propose testable hypotheses to explain how the viral shell becomes destabilized, leading to RNA uncoating. These findings give us a better understanding of how poliovirus has evolved to exploit a natural process of its host to penetrate the membrane barrier.
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Panjwani A, Strauss M, Gold S, Wenham H, Jackson T, Chou JJ, Rowlands DJ, Stonehouse NJ, Hogle JM, Tuthill TJ. Capsid protein VP4 of human rhinovirus induces membrane permeability by the formation of a size-selective multimeric pore. PLoS Pathog 2014; 10:e1004294. [PMID: 25102288 PMCID: PMC4125281 DOI: 10.1371/journal.ppat.1004294] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Accepted: 06/24/2014] [Indexed: 01/18/2023] Open
Abstract
Non-enveloped viruses must deliver their viral genome across a cell membrane without the advantage of membrane fusion. The mechanisms used to achieve this remain poorly understood. Human rhinovirus, a frequent cause of the common cold, is a non-enveloped virus of the picornavirus family, which includes other significant pathogens such as poliovirus and foot-and-mouth disease virus. During picornavirus cell entry, the small myristoylated capsid protein VP4 is released from the virus, interacts with the cell membrane and is implicated in the delivery of the viral RNA genome into the cytoplasm to initiate replication. In this study, we have produced recombinant C-terminal histidine-tagged human rhinovirus VP4 and shown it can induce membrane permeability in liposome model membranes. Dextran size-exclusion studies, chemical crosslinking and electron microscopy demonstrated that VP4 forms a multimeric membrane pore, with a channel size consistent with transfer of the single-stranded RNA genome. The membrane permeability induced by recombinant VP4 was influenced by pH and was comparable to permeability induced by infectious virions. These findings present a molecular mechanism for the involvement of VP4 in cell entry and provide a model system which will facilitate exploration of VP4 as a novel antiviral target for the picornavirus family. Human rhinovirus (HRV) is a non-enveloped virus of the picornavirus family and is responsible for respiratory infections (common colds) costing billions of dollars ($) annually. There remains no vaccine or licensed drug to prevent or reduce infection. Related members of the picornavirus family include significant pathogens such as poliovirus, enterovirus 71 and foot-and-mouth disease virus, for which improved control measures are also required. A fundamental step in virus infection is the delivery of the viral genetic material through the barrier of the cellular membrane. Viruses such as HIV and influenza are enveloped in an outer membrane which can fuse with the host cell membrane to allow the viral genome to penetrate into the cytoplasm. However, non-enveloped viruses such as picornaviruses lack a membrane and the mechanisms for penetration of the membrane by these viruses remain poorly understood. The capsid protein VP4 has previously been implicated in the delivery of the picornavirus genome. In this study we demonstrate that HRV VP4 interacts with membranes to make them permeable by the formation of multimeric, size-selective membrane pores with properties consistent with the transport of viral genome through the membrane. This function of VP4 provides a novel antiviral target for this family of viruses.
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Affiliation(s)
- Anusha Panjwani
- The Pirbright Institute, Pirbright, Surrey, United Kingdom
- School of Molecular and Cellular Biology & Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, West Yorkshire, United Kingdom
| | - Mike Strauss
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sarah Gold
- The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Hannah Wenham
- The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Terry Jackson
- The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - James J. Chou
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David J. Rowlands
- School of Molecular and Cellular Biology & Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, West Yorkshire, United Kingdom
| | - Nicola J. Stonehouse
- School of Molecular and Cellular Biology & Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, West Yorkshire, United Kingdom
| | - James M. Hogle
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
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Abstract
Inactivated polio vaccines, which have been used in many countries for more than 50 years, are produced by treating live poliovirus (PV) with formaldehyde. However, the molecular mechanisms underlying virus inactivation are not well understood. Infection by PV is initiated by virus binding to specific cell receptors, which results in viral particles undergoing sequential conformational changes that generate altered structural forms (135S and 80S particles) and leads to virus cell entry. We have analyzed the ability of inactivated PV to bind to the human poliovirus receptor (hPVR) using various techniques such as ultracentrifugation, fluorescence-activated cell sorting flow cytometry and real-time reverse transcription-PCR (RT-PCR). The results showed that although retaining the ability to bind to hPVR, inactivated PV bound less efficiently in comparison to live PV. We also found that inactivated PV showed resistance to structural conversion in vitro, as judged by measuring changes in antigenicity, the ability to bind to hPVR, and viral RNA release at high temperature. Furthermore, viral RNA from inactivated PV was shown to be modified, since cDNA yields obtained by RT-PCR amplification were severely reduced and no infectious virus was recovered after RNA transfection into susceptible cells. Importance: This study represents a novel insight into the molecular mechanisms responsible for poliovirus inactivation. We show that inactivation with formaldehyde has an effect on early steps of viral replication as it reduces the ability of PV to bind to hPVR, decreases the sensitivity of PV to convert to 135S particles, and abolishes the infectivity of its viral RNA. These changes are likely responsible for the loss of infectivity shown by PV following inactivation. Techniques used in this study represent new approaches for the characterization of inactivated PV products and could be useful in developing improved methods for the production and quality control testing of inactivated polio vaccines. Measuring the antigenicity, capsid stability, and RNA integrity of inactivated PV samples could help establishing the optimal balance between the loss of infectivity and the preservation of virus antigenicity during inactivation.
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Yamayoshi S, Fujii K, Koike S. Receptors for enterovirus 71. Emerg Microbes Infect 2014; 3:e53. [PMID: 26038749 PMCID: PMC4126179 DOI: 10.1038/emi.2014.49] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 04/05/2014] [Accepted: 05/05/2014] [Indexed: 11/10/2022]
Abstract
Enterovirus 71 (EV71) is one of the major causative agents of hand, foot and mouth disease (HFMD). Occasionally, EV71 infection is associated with severe neurological diseases, such as acute encephalitis, acute flaccid paralysis and cardiopulmonary failure. Several molecules act as cell surface receptors that stimulate EV71 infection, including scavenger receptor B2 (SCARB2), P-selectin glycoprotein ligand-1 (PSGL-1), sialylated glycan, heparan sulfate and annexin II (Anx2). SCARB2 plays critical roles in attachment, viral entry and uncoating, and it can facilitate efficient EV71 infection. The three-dimensional structures of the mature EV71 virion, procapsid and empty capsid, as well as the exofacial domain of SCARB2, have been elucidated. This structural information has greatly increased our understanding of the early steps of EV71 infection. Furthermore, SCARB2 plays essential roles in the development of EV71 neurological disease in vivo. Adult mice are not susceptible to infection by EV71, but transgenic mice that express human SCARB2 become susceptible to EV71 infection and develop similar neurological diseases to those found in humans. This mouse model facilitates the in vivo investigation of many issues related to EV71. PSGL-1, sialylated glycan, heparan sulfate and Anx2 are attachment receptors, which enhance viral infection by retaining the virus on the cell surface. These molecules also contribute to viral infection in vitro either by interacting with SCARB2 or independently of SCARB2. However, the cooperative effects of these receptors, and their contribution to EV71 pathogenicity in vivo, remain to be elucidated.
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Affiliation(s)
- Seiya Yamayoshi
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, The University of Tokyo , Tokyo 108-8639, Japan
| | - Ken Fujii
- Neurovirology Project, Tokyo Metropolitan Institute of Medical Science , Tokyo 156-8506, Japan
| | - Satoshi Koike
- Neurovirology Project, Tokyo Metropolitan Institute of Medical Science , Tokyo 156-8506, Japan
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Mechanism of action and capsid-stabilizing properties of VHHs with an in vitro antipolioviral activity. J Virol 2014; 88:4403-13. [PMID: 24501405 DOI: 10.1128/jvi.03402-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED Previously, we reported on the in vitro antiviral activity of single-domain antibody fragments (VHHs) directed against poliovirus type 1. Five VHHs were found to neutralize poliovirus type 1 in an in vitro setting and showed 50% effective concentrations (EC50s) in the nanomolar range. In the present study, we further investigated the mechanism of action of these VHHs. All five VHHs interfere at multiple levels of the viral replication cycle, as they interfere both with attachment of the virus to cells and with viral uncoating. The latter effect is consistent with their ability to stabilize the poliovirus capsid, as observed in a ThermoFluor thermal shift assay, in which the virus is gradually heated and the temperature causing 50% of the RNA to be released from the capsid is determined, either in the presence or in the absence of the VHHs. The VHH-capsid interactions were also seen to induce aggregation of the virus-VHH complexes. However, this observation cannot yet be linked to their mechanism of action. Cryo-electron microscopy (cryo-EM) reconstructions of two VHHs in complex with poliovirus type 1 show no conformational changes of the capsid to explain this aggregation. On the other hand, these reconstructions do show that the binding sites of VHHs PVSP6A and PVSP29F overlap the binding site for the poliovirus receptor (CD155/PVR) and span interfaces that are altered during receptor-induced conformational changes associated with cell entry. This may explain the interference at the level of cell attachment of the virus as well as their effect on uncoating. IMPORTANCE The study describes the mechanism of neutralization and the capsid-stabilizing activity of five single-domain antibody fragments (VHHs) that have an in vitro neutralizing activity against poliovirus type 1. The results show that the VHHs interfere at multiple levels of the viral replication cycle (cell attachment and viral uncoating). These mechanisms are possibly shared by some conventional antibodies and may therefore provide some insight into the natural immune responses. Since the binding sites of two VHHs studied by cryo-EM are very similar to that of the receptor, the VHHs can be used as probes to study the authentic virus-cell interaction. The structures and conclusions in this study are original and raise interesting findings regarding virus-receptor interactions and the order of key events early in infection.
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43
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Abstract
UNLABELLED Human enterovirus 71 (EV71) is the major causative agent of severe hand-foot-and-mouth diseases (HFMD) in young children, and structural characterization of EV71 during its life cycle can aid in the development of therapeutics against HFMD. Here, we present the atomic structures of the full virion and an uncoating intermediate of a clinical EV71 C4 strain to illustrate the structural changes in the full virion that lead to the formation of the uncoating intermediate prepared for RNA release. Although the VP1 N-terminal regions observed to penetrate through the junction channel at the quasi-3-fold axis in the uncoating intermediate of coxsackievirus A16 were not observed in the EV71 uncoating intermediate, drastic conformational changes occur in this region, as has been observed in all capsid proteins. Additionally, the RNA genome interacts with the N-terminal extensions of VP1 and residues 32 to 36 of VP3, both of which are situated at the bottom of the junction. These observations highlight the importance of the junction for genome release. Furthermore, EV71 uncoating is associated with apparent rearrangements and expansion around the 2- and 5-fold axes without obvious changes around the 3-fold axes. Therefore, these structures enabled the identification of hot spots for capsid rearrangements, which led to the hypothesis that the protomer interface near the junction and the 2-fold axis permits the opening of large channels for the exit of polypeptides and viral RNA, which is an uncoating mechanism that is likely conserved in enteroviruses. IMPORTANCE Human enterovirus 71 (EV71) is the major causative agent of severe hand-foot-and-mouth diseases (HFMD) in young children. EV71 contains an RNA genome protected by an icosahedral capsid shell. Uncoating is essential in EV71 life cycle, which is characterized by conformational changes in the capsid to facilitate RNA release into host cell. Here we present the atomic structures of the full virion and an uncoating intermediate of a clinical C4 strain of EV71. Structural analysis revealed drastic conformational changes associated with uncoating in all the capsid proteins near the junction at the quasi-3-fold axis and protein-RNA interactions at the bottom of the junction in the uncoating intermediate. Significant capsid rearrangements also occur at the icosahedral 2- and 5-fold axes but not at the 3-fold axis. Taking the results together, we hypothesize that the junction and nearby areas are hot spots for capsid breaches for the exit of polypeptides and viral RNA during uncoating.
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44
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Cryo-electron microscopy reconstruction shows poliovirus 135S particles poised for membrane interaction and RNA release. J Virol 2013; 88:1758-70. [PMID: 24257617 DOI: 10.1128/jvi.01949-13] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
During infection, binding of mature poliovirus to cell surface receptors induces an irreversible expansion of the capsid, to form an infectious cell-entry intermediate particle that sediments at 135S. In these expanded virions, the major capsid proteins (VP1 to VP3) adopt an altered icosahedral arrangement to open holes in the capsid at 2-fold and quasi-3-fold axes, and internal polypeptides VP4 and the N terminus of VP1, which can bind membranes, become externalized. Cryo-electron microscopy images for 117,330 particles were collected using Leginon and reconstructed using FREALIGN. Improved rigid-body positioning of major capsid proteins established reliably which polypeptide segments become disordered or rearranged. The virus-to-135S transition includes expansion of 4%, rearrangements of the GH loops of VP3 and VP1, and disordering of C-terminal extensions of VP1 and VP2. The N terminus of VP1 rearranges to become externalized near its quasi-3-fold exit, binds to rearranged GH loops of VP3 and VP1, and attaches to the top surface of VP2. These details improve our understanding of subsequent stages of infection, including endocytosis and RNA transfer into the cytoplasm.
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45
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Ren J, Wang X, Hu Z, Gao Q, Sun Y, Li X, Porta C, Walter TS, Gilbert RJ, Zhao Y, Axford D, Williams M, McAuley K, Rowlands DJ, Yin W, Wang J, Stuart DI, Rao Z, Fry EE. Picornavirus uncoating intermediate captured in atomic detail. Nat Commun 2013; 4:1929. [PMID: 23728514 PMCID: PMC3709478 DOI: 10.1038/ncomms2889] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Accepted: 04/13/2013] [Indexed: 01/07/2023] Open
Abstract
It remains largely mysterious how the genomes of non-enveloped eukaryotic viruses are transferred across a membrane into the host cell. Picornaviruses are simple models for such viruses, and initiate this uncoating process through particle expansion, which reveals channels through which internal capsid proteins and the viral genome presumably exit the particle, although this has not been clearly seen until now. Here we present the atomic structure of an uncoating intermediate for the major human picornavirus pathogen CAV16, which reveals VP1 partly extruded from the capsid, poised to embed in the host membrane. Together with previous low-resolution results, we are able to propose a detailed hypothesis for the ordered egress of the internal proteins, using two distinct sets of channels through the capsid, and suggest a structural link to the condensed RNA within the particle, which may be involved in triggering RNA release.
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Affiliation(s)
- Jingshan Ren
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK,These authors contributed equally to this work
| | - Xiangxi Wang
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China,These authors contributed equally to this work
| | - Zhongyu Hu
- National Institutes for Food and Drug Control, No. 2, Tiantan Xili, Beijing 100050, China
| | - Qiang Gao
- Sinovac Biotech Co., Ltd, Beijing 100085, China
| | - Yao Sun
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China
| | - Xuemei Li
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China
| | - Claudine Porta
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
| | - Thomas S. Walter
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
| | - Robert J. Gilbert
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
| | - Yuguang Zhao
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
| | - Danny Axford
- Diamond Light Sources, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - Mark Williams
- Diamond Light Sources, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - Katherine McAuley
- Diamond Light Sources, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - David J. Rowlands
- Faculty of Biological Sciences, Institute of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Weidong Yin
- Sinovac Biotech Co., Ltd, Beijing 100085, China
| | - Junzhi Wang
- National Institutes for Food and Drug Control, No. 2, Tiantan Xili, Beijing 100050, China,
| | - David I. Stuart
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK,Diamond Light Sources, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK,
| | - Zihe Rao
- National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China,Laboratory of Structural Biology, School of Medicine, Tsinghua University, Beijing, 100084, China,State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300071, China
| | - Elizabeth E. Fry
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, UK
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Shingler KL, Yoder JL, Carnegie MS, Ashley RE, Makhov AM, Conway JF, Hafenstein S. The enterovirus 71 A-particle forms a gateway to allow genome release: a cryoEM study of picornavirus uncoating. PLoS Pathog 2013; 9:e1003240. [PMID: 23555253 PMCID: PMC3605244 DOI: 10.1371/journal.ppat.1003240] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 01/28/2013] [Indexed: 12/30/2022] Open
Abstract
Since its discovery in 1969, enterovirus 71 (EV71) has emerged as a serious worldwide health threat. This human pathogen of the picornavirus family causes hand, foot, and mouth disease, and also has the capacity to invade the central nervous system to cause severe disease and death. Upon binding to a host receptor on the cell surface, the virus begins a two-step uncoating process, first forming an expanded, altered “A-particle”, which is primed for genome release. In a second step after endocytosis, an unknown trigger leads to RNA expulsion, generating an intact, empty capsid. Cryo-electron microscopy reconstructions of these two capsid states provide insight into the mechanics of genome release. The EV71 A-particle capsid interacts with the genome near the icosahedral two-fold axis of symmetry, which opens to the external environment via a channel ∼10 Å in diameter that is lined with patches of negatively charged residues. After the EV71 genome has been released, the two-fold channel shrinks, though the overall capsid dimensions are conserved. These structural characteristics identify the two-fold channel as the site where a gateway forms and regulates the process of genome release. In a picornavirus capsid structural integrity must not be compromised until a key mechanism triggers genome release into a permissive cell. It has long been established that the majority of members of the picornavirus family solve this dilemma with a two-step uncoating process initiated by receptor recognition. For human enteroviruses, binding of an entry receptor triggers a series of conformational changes, resulting in an “A-particle” that is primed for genome release. After endocytosis, an unknown trigger causes the A-particle to expel the viral genome, leaving behind an emptied capsid. This process can be mimicked in solution by heating mature virus. Though the capsid species for both of these steps have been isolated, the fine details of the uncoating process have yet to be elucidated. Cryo-electron microscopy reconstructions of the enterovirus 71 A-particle and empty capsid provide compelling structural evidence to suggest that the icosahedral two-fold axis opens a channel that acts as a gateway in the viral capsid, regulating the release of genomic material from the altered particle.
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Affiliation(s)
- Kristin L. Shingler
- Department of Medicine, Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Jennifer L. Yoder
- Department of Medicine, Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Michael S. Carnegie
- Department of Medicine, Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Robert E. Ashley
- Department of Medicine, Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Alexander M. Makhov
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - James F. Conway
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Susan Hafenstein
- Department of Medicine, Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail:
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47
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RNA transfer from poliovirus 135S particles across membranes is mediated by long umbilical connectors. J Virol 2013; 87:3903-14. [PMID: 23365424 DOI: 10.1128/jvi.03209-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
During infection, the binding of poliovirus to its cell surface receptor at 37°C triggers an expansion of the virus in which internal polypeptides that bind to membranes are externalized. Subsequently, in a poorly understood process, the viral RNA genome is transferred directly across an endosomal membrane, and into the host cell cytoplasm, to initiate infection. Here, cryoelectron tomography demonstrates the results of 37°C warming of a poliovirus-receptor-liposome model complex that was produced using Ni-nitrilotriacetic acid lipids and His-tagged receptor ectodomains. In total, 651 subtomographic volumes were aligned, classified, and averaged to obtain detailed pictures, showing both the conversion of virus into its expanded form and the passage of RNA into intact liposomes. Unexpectedly, the virus and membrane surfaces were located ∼50 Å apart, with the 5-fold axis tilted away from the perpendicular, and the solvent spaces between them were spanned by either one or two long "umbilical" density features that lie at an angle to the virus and membrane. The thinner connector, which sometimes appears alone, is 28 to 30 Å in diameter and has a footprint on the virus surface located close to either a 5-fold or a 3-fold axis. The broader connector has a footprint near the quasi-3-fold hole that opens upon virus expansion and is hypothesized to include RNA, shielded from enzymatic degradation by polypeptides that include the N-terminal extension of VP1 and capsid protein VP4. The implications of these observations for the mechanism of RNase-protected RNA transfer in picornaviruses are discussed.
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48
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Bergelson JM, Coyne CB. Picornavirus entry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 790:24-41. [PMID: 23884584 DOI: 10.1007/978-1-4614-7651-1_2] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The essential event in picornavirus entry is the delivery of the RNA genome to the cytoplasm of a target cell, where replication occurs. In the past several years progress has been made in understanding the structural changes in the virion important for uncoating and RNA release. In addition, for several viruses the endocytic mechanisms responsible for internalization have been identified, as have the cellular sites at which uncoating occurs. It has become clear that entry is not a passive process, and that viruses initiate specific signals required for entry. And we have begun to recognize that for a given virus, there may be multiple routes of entry, depending on the particular target cell and the receptors available on that cell.
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Affiliation(s)
- Jeffrey M Bergelson
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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49
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Galaway FA, Stockley PG. MS2 Viruslike Particles: A Robust, Semisynthetic Targeted Drug Delivery Platform. Mol Pharm 2012; 10:59-68. [DOI: 10.1021/mp3003368] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Francis A. Galaway
- Astbury Centre
for Structural Molecular Biology, University
of Leeds, Leeds, LS2 9JT, U.K
| | - Peter G. Stockley
- Astbury Centre
for Structural Molecular Biology, University
of Leeds, Leeds, LS2 9JT, U.K
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50
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The crystal structure of a coxsackievirus B3-RD variant and a refined 9-angstrom cryo-electron microscopy reconstruction of the virus complexed with decay-accelerating factor (DAF) provide a new footprint of DAF on the virus surface. J Virol 2012; 86:12571-81. [PMID: 22973031 DOI: 10.1128/jvi.01592-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The coxsackievirus-adenovirus receptor (CAR) and decay-accelerating factor (DAF) have been identified as cellular receptors for coxsackievirus B3 (CVB3). The first described DAF-binding isolate was obtained during passage of the prototype strain, Nancy, on rhabdomyosarcoma (RD) cells, which express DAF but very little CAR. Here, the structure of the resulting variant, CVB3-RD, has been solved by X-ray crystallography to 2.74 Å, and a cryo-electron microscopy reconstruction of CVB3-RD complexed with DAF has been refined to 9.0 Å. This new high-resolution structure permits us to correct an error in our previous view of DAF-virus interactions, providing a new footprint of DAF that bridges two adjacent protomers. The contact sites between the virus and DAF clearly encompass CVB3-RD residues recently shown to be required for binding to DAF; these residues interact with DAF short consensus repeat 2 (SCR2), which is known to be essential for virus binding. Based on the new structure, the mode of the DAF interaction with CVB3 differs significantly from the mode reported previously for DAF binding to echoviruses.
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