1
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Devantier K, Kjær VMS, Griffin S, Kragelund BB, Rosenkilde MM. Advancing the field of viroporins-Structure, function and pharmacology: IUPHAR Review 39. Br J Pharmacol 2024; 181:4450-4490. [PMID: 39224966 DOI: 10.1111/bph.17317] [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: 02/15/2024] [Revised: 06/28/2024] [Accepted: 07/07/2024] [Indexed: 09/04/2024] Open
Abstract
Viroporins possess important potential as antiviral targets due to their critical roles during virus life cycles, spanning from virus entry to egress. Although the antiviral amantadine targets the M2 viroporin of influenza A virus, successful progression of other viroporin inhibitors into clinical use remains challenging. These challenges relate in varying proportions to a lack of reliable full-length 3D-structures, difficulties in functionally characterising individual viroporins, and absence of verifiable direct binding between inhibitor and viroporin. This review offers perspectives to help overcome these challenges. We provide a comprehensive overview of the viroporin family, including their structural and functional features, highlighting the moldability of their energy landscapes and actions. To advance the field, we suggest a list of best practices to aspire towards unambiguous viroporin identification and characterisation, along with considerations of potential pitfalls. Finally, we present current and future scenarios of, and prospects for, viroporin targeting drugs.
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Affiliation(s)
- Kira Devantier
- Molecular and Translational Pharmacology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Viktoria M S Kjær
- Molecular and Translational Pharmacology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stephen Griffin
- Leeds Institute of Medical Research, St James' University Hospital, School of Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Mette M Rosenkilde
- Molecular and Translational Pharmacology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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2
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Cedillo-Barrón L, García-Cordero J, Visoso-Carvajal G, León-Juárez M. Viroporins Manipulate Cellular Powerhouses and Modulate Innate Immunity. Viruses 2024; 16:345. [PMID: 38543711 PMCID: PMC10974846 DOI: 10.3390/v16030345] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/02/2024] [Accepted: 02/02/2024] [Indexed: 05/23/2024] Open
Abstract
Viruses have a wide repertoire of molecular strategies that focus on their replication or the facilitation of different stages of the viral cycle. One of these strategies is mediated by the activity of viroporins, which are multifunctional viral proteins that, upon oligomerization, exhibit ion channel properties with mild ion selectivity. Viroporins facilitate multiple processes, such as the regulation of immune response and inflammasome activation through the induction of pore formation in various cell organelle membranes to facilitate the escape of ions and the alteration of intracellular homeostasis. Viroporins target diverse membranes (such as the cellular membrane), endoplasmic reticulum, and mitochondria. Cumulative data regarding the importance of mitochondria function in multiple processes, such as cellular metabolism, energy production, calcium homeostasis, apoptosis, and mitophagy, have been reported. The direct or indirect interaction of viroporins with mitochondria and how this interaction affects the functioning of mitochondrial cells in the innate immunity of host cells against viruses remains unclear. A better understanding of the viroporin-mitochondria interactions will provide insights into their role in affecting host immune signaling through the mitochondria. Thus, in this review, we mainly focus on descriptions of viroporins and studies that have provided insights into the role of viroporins in hijacked mitochondria.
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Affiliation(s)
- Leticia Cedillo-Barrón
- Department of Molecular Biomedicine, Center for Research and Advanced Studies (CINVESTAV-IPN) Av., IPN # 2508 Col., San Pedro Zacatenco, Mexico City 07360, Mexico; (J.G.-C.); (G.V.-C.)
| | - Julio García-Cordero
- Department of Molecular Biomedicine, Center for Research and Advanced Studies (CINVESTAV-IPN) Av., IPN # 2508 Col., San Pedro Zacatenco, Mexico City 07360, Mexico; (J.G.-C.); (G.V.-C.)
| | - Giovani Visoso-Carvajal
- Department of Molecular Biomedicine, Center for Research and Advanced Studies (CINVESTAV-IPN) Av., IPN # 2508 Col., San Pedro Zacatenco, Mexico City 07360, Mexico; (J.G.-C.); (G.V.-C.)
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Salvador Díaz Mirón esq, Plan de San Luis S/N, Miguel Hidalgo, Casco de Santo Tomas, Mexico City 11340, Mexico
| | - Moisés León-Juárez
- Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Mexico City 11000, Mexico;
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3
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Surya W, Tavares-Neto E, Sanchis A, Queralt-Martín M, Alcaraz A, Torres J, Aguilella VM. The Complex Proteolipidic Behavior of the SARS-CoV-2 Envelope Protein Channel: Weak Selectivity and Heterogeneous Oligomerization. Int J Mol Sci 2023; 24:12454. [PMID: 37569828 PMCID: PMC10420310 DOI: 10.3390/ijms241512454] [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: 07/07/2023] [Revised: 07/27/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
The envelope (E) protein is a small polypeptide that can form ion channels in coronaviruses. In SARS coronavirus 2 (SARS-CoV-2), the agent that caused the recent COVID-19 pandemic, and its predecessor SARS-CoV-1, E protein is found in the endoplasmic reticulum-Golgi intermediate compartment (ERGIC), where virion budding takes place. Several reports claim that E protein promotes the formation of "cation-selective channels". However, whether this term represents specificity to certain ions (e.g., potassium or calcium) or the partial or total exclusion of anions is debatable. Herein, we discuss this claim based on the available data for SARS-CoV-1 and -2 E and on new experiments performed using the untagged full-length E protein from SARS-CoV-2 in planar lipid membranes of different types, including those that closely mimic the ERGIC membrane composition. We provide evidence that the selectivity of the E-induced channels is very mild and depends strongly on lipid environment. Thus, despite past and recent claims, we found no indication that the E protein forms cation-selective channels that prevent anion transport, and even less that E protein forms bona fide specific calcium channels. In fact, the E channel maintains its multi-ionic non-specific neutral character even in concentrated solutions of Ca2+ ions. Also, in contrast to previous studies, we found no evidence that SARS-CoV-2 E channel activation requires a particular voltage, high calcium concentrations or low pH, in agreement with available data from SARS-CoV-1 E. In addition, sedimentation velocity experiments suggest that the E channel population is mostly pentameric, but very dynamic and probably heterogeneous, consistent with the broad distribution of conductance values typically found in electrophysiological experiments. The latter has been explained by the presence of proteolipidic channel structures.
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Affiliation(s)
- Wahyu Surya
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore;
| | - Ernesto Tavares-Neto
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12080 Castellon, Spain; (E.T.-N.); (M.Q.-M.); (A.A.)
| | - Andrea Sanchis
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12080 Castellon, Spain; (E.T.-N.); (M.Q.-M.); (A.A.)
| | - María Queralt-Martín
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12080 Castellon, Spain; (E.T.-N.); (M.Q.-M.); (A.A.)
| | - Antonio Alcaraz
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12080 Castellon, Spain; (E.T.-N.); (M.Q.-M.); (A.A.)
| | - Jaume Torres
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore;
| | - Vicente M. Aguilella
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12080 Castellon, Spain; (E.T.-N.); (M.Q.-M.); (A.A.)
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4
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Perini DA, Parra-Ortiz E, Varó I, Queralt-Martín M, Malmsten M, Alcaraz A. Surface-Functionalized Polystyrene Nanoparticles Alter the Transmembrane Potential via Ion-Selective Pores Maintaining Global Bilayer Integrity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:14837-14849. [PMID: 36417698 PMCID: PMC9974068 DOI: 10.1021/acs.langmuir.2c02487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Although nanoplastics have well-known toxic effects toward the environment and living organisms, their molecular toxicity mechanisms, including the nature of nanoparticle-cell membrane interactions, are still under investigation. Here, we employ dynamic light scattering, quartz crystal microbalance with dissipation monitoring, and electrophysiology to investigate the interaction between polystyrene nanoparticles (PS NPs) and phospholipid membranes. Our results show that PS NPs adsorb onto lipid bilayers creating soft inhomogeneous films that include disordered defects. PS NPs form an integral part of the generated channels so that the surface functionalization and charge of the NP determine the pore conductive properties. The large difference in size between the NP diameter and the lipid bilayer thickness (∼60 vs ∼5 nm) suggests a particular and complex lipid-NP assembly that is able to maintain overall membrane integrity. In view of this, we suggest that NP-induced toxicity in cells could operate in more subtle ways than membrane disintegration, such as inducing lipid reorganization and transmembrane ionic fluxes that disrupt the membrane potential.
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Affiliation(s)
- D. Aurora Perini
- Laboratory
of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12071Castellón, Spain
| | - Elisa Parra-Ortiz
- Department
of Pharmacy, University of Copenhagen, DK-2100Copenhagen, Denmark
| | - Inmaculada Varó
- Institute
of Aquaculture Torre de la Sal (IATS-CSIC), Ribera de Cabanes, 12595Castellón, Spain
| | - María Queralt-Martín
- Laboratory
of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12071Castellón, Spain
| | - Martin Malmsten
- Department
of Pharmacy, University of Copenhagen, DK-2100Copenhagen, Denmark
- Department
of Physical Chemistry 1, University of Lund, SE-22100Lund, Sweden
| | - Antonio Alcaraz
- Laboratory
of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12071Castellón, Spain
- . Tel.: +34 964 72 8044
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5
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Perini DA, Aguilella-Arzo M, Alcaraz A, Perálvarez-Marín A, Queralt-Martín M. Dynorphin A induces membrane permeabilization by formation of proteolipidic pores. Insights from electrophysiology and computational simulations. Comput Struct Biotechnol J 2022; 20:230-240. [PMID: 35024095 PMCID: PMC8718563 DOI: 10.1016/j.csbj.2021.12.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/13/2021] [Accepted: 12/13/2021] [Indexed: 01/14/2023] Open
Abstract
Dynorphins are endogenous neuropeptides that function as ligands for the κ-opioid receptor. In addition to opioid activity, dynorphins can induce several pathological effects such as neurological dysfunctions and cell death. Previous studies have suggested that Dynorphin A (DynA) mediates some pathogenic actions through formation of transient pores in lipid domains of the plasma membrane. Here, we use planar bilayer electrophysiology to show that DynA induces pore formation in negatively charged membranes. We find a large variability in pore conformations showing equilibrium conductance fluctuations, what disregards electroporation as the dominant mechanism of pore formation. Ion selectivity measurements showing cationic selectivity indicate that positive protein charges of DynA are stabilized by phosphatidyl serine negative charges in the formation of combined structures. We complement our study with computational simulations that assess the stability of diverse peptide arrangements in the hydrophobic core of the bilayer. We show that DynA is capable of assembling in charged membranes to form water-filled pores that conduct ions.
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Affiliation(s)
- D Aurora Perini
- Laboratory of Molecular Biophysics. Department of Physics. Universitat Jaume I, 12071 Castellón, Spain
| | - Marcel Aguilella-Arzo
- Laboratory of Molecular Biophysics. Department of Physics. Universitat Jaume I, 12071 Castellón, Spain
| | - Antonio Alcaraz
- Laboratory of Molecular Biophysics. Department of Physics. Universitat Jaume I, 12071 Castellón, Spain
| | - Alex Perálvarez-Marín
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain.,Institute of Neuroscience, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain
| | - María Queralt-Martín
- Laboratory of Molecular Biophysics. Department of Physics. Universitat Jaume I, 12071 Castellón, Spain
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6
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Cao Y, Yang R, Lee I, Zhang W, Sun J, Wang W, Meng X. Characterization of the SARS-CoV-2 E Protein: Sequence, Structure, Viroporin, and Inhibitors. Protein Sci 2021; 30:1114-1130. [PMID: 33813796 PMCID: PMC8138525 DOI: 10.1002/pro.4075] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/29/2021] [Accepted: 03/30/2021] [Indexed: 12/19/2022]
Abstract
The COVID-19 epidemic is one of the most influential epidemics in history. Understanding the impact of coronaviruses (CoVs) on host cells is very important for disease treatment. The SARS-CoV-2 envelope (E) protein is a small structural protein involved in many aspects of the viral life cycle. The E protein promotes the packaging and reproduction of the virus, and deletion of this protein weakens or even abolishes the virulence. This review aims to establish new knowledge by combining recent advances in the study of the SARS-CoV-2 E protein and by comparing it with the SARS-CoV E protein. The E protein amino acid sequence, structure, self-assembly characteristics, viroporin mechanisms and inhibitors are summarized and analyzed herein. Although the mechanisms of the SARS-CoV-2 and SARS-CoV E proteins are similar in many respects, specific studies on the SARS-CoV-2 E protein, for both monomers and oligomers, are still lacking. A comprehensive understanding of this protein should prompt further studies on the design and characterization of effective targeted therapeutic measures.
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Affiliation(s)
- Yipeng Cao
- Tianjin Medical University Cancer Institute and HospitalKey Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, National Clinical Research Center for CancerTianjinPeople's Republic of China
- National Supercomputer Center in TianjinTEDA‐Tianjin Economic‐Technological Development AreaTianjinPeople's Republic of China
| | - Rui Yang
- Department of Infection and ImmunityTianjin Union Medical Center, Nankai University Affiliated HospitalTianjinPeople's Republic of China
| | - Imshik Lee
- College of PhysicsNankai UniversityTianjinPeople's Republic of China
| | - Wenwen Zhang
- Tianjin Medical University Cancer Institute and HospitalKey Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, National Clinical Research Center for CancerTianjinPeople's Republic of China
| | - Jiana Sun
- Tianjin Medical University Cancer Institute and HospitalKey Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, National Clinical Research Center for CancerTianjinPeople's Republic of China
| | - Wei Wang
- Tianjin Medical University Cancer Institute and HospitalKey Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, National Clinical Research Center for CancerTianjinPeople's Republic of China
| | - Xiangfei Meng
- National Supercomputer Center in TianjinTEDA‐Tianjin Economic‐Technological Development AreaTianjinPeople's Republic of China
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7
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Riedel C, Aitkenhead H, El Omari K, Rümenapf T. Atypical Porcine Pestiviruses: Relationships and Conserved Structural Features. Viruses 2021; 13:v13050760. [PMID: 33926056 PMCID: PMC8146772 DOI: 10.3390/v13050760] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 01/22/2023] Open
Abstract
For two decades, the genus pestivirus has been expanding and the host range now extends to rodents, bats and marine mammals. In this review, we focus on one of the most diverse pestiviruses, atypical porcine pestivirus or pestivirus K, comparing its special traits to what is already known at the structural and functional level from other pestiviruses.
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Affiliation(s)
- Christiane Riedel
- Institute of Virology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria;
- Correspondence:
| | - Hazel Aitkenhead
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (H.A.); (K.E.O.)
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0FA, UK
| | - Kamel El Omari
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (H.A.); (K.E.O.)
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0FA, UK
| | - Till Rümenapf
- Institute of Virology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria;
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8
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Transport mechanisms of SARS-CoV-E viroporin in calcium solutions: Lipid-dependent Anomalous Mole Fraction Effect and regulation of pore conductance. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183590. [PMID: 33621516 PMCID: PMC7896491 DOI: 10.1016/j.bbamem.2021.183590] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 02/06/2023]
Abstract
The envelope protein E of the SARS-CoV coronavirus is an archetype of viroporin. It is a small hydrophobic protein displaying ion channel activity that has proven highly relevant in virus-host interaction and virulence. Ion transport through E channel was shown to alter Ca2+ homeostasis in the cell and trigger inflammation processes. Here, we study transport properties of the E viroporin in mixed solutions of potassium and calcium chloride that contain a fixed total concentration (mole fraction experiments). The channel is reconstituted in planar membranes of different lipid compositions, including a lipid mixture that mimics the endoplasmic reticulum-Golgi intermediate compartment (ERGIC) membrane where the virus localizes within the cell. We find that the E ion conductance changes non-monotonically with the total ionic concentration displaying an Anomalous Mole Fraction Effect (AMFE) only when charged lipids are present in the membrane. We also observe that E channel insertion in ERGIC-mimic membranes – including lipid with intrinsic negative curvature – enhances ion permeation at physiological concentrations of pure CaCl2 or KCl solutions, with a preferential transport of Ca2+ in mixed KCl-CaCl2 solutions. Altogether, our findings demonstrate that the presence of calcium modulates the transport properties of the E channel by interacting preferentially with charged lipids through different mechanisms including direct Coulombic interactions and possibly inducing changes in membrane morphology.
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9
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Shi JM, Zhu L, Lan X, Zhao DW, He YJ, Sun ZQ, Wu D, Li HY. Endocytosis Is a Key Mode of Interaction between Extracellular β-Amyloid and the Cell Membrane. Biophys J 2020; 119:1078-1090. [PMID: 32857960 PMCID: PMC7499104 DOI: 10.1016/j.bpj.2020.07.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/21/2020] [Accepted: 07/08/2020] [Indexed: 11/23/2022] Open
Abstract
Interactions between amyloid-β peptide (Aβ) and the cell membrane include interaction with membrane lipids and binding to membrane receptors, both of which are considered to be the toxicity mechanisms of Aβ. However, it is unclear whether both mechanisms lead to cytotoxicity. Thus, we aimed to analyze these two mechanisms of Aβ42 interaction with cell membranes under different Aβ aggregation states. To this end, model membrane experiments were conducted. Quantitative analysis of Aβ42 monomers or oligomers bound to the membrane of neuro-2a cells was also performed, and laser confocal microscopy was employed to assess endocytosis of FITC-Aβ42 monomers or oligomers by neuro-2a cells. We found that the binding capacity of Aβ42 to membrane lipids was weak and that the amount of Aβ42 bound to membrane lipids was low. Moreover, clathrin-mediated endocytosis of Aβ42 oligomers by neuro-2a cells was observed. Endocytosis serves as a key mode of interaction between extracellular Aβ42 and neurons. These findings provide insights into the mechanisms underlying Aβ oligomer metabolism.
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Affiliation(s)
- Jing-Ming Shi
- School of Medicine, Xizang Minzu University, Xian' yang, Shaanxi, P.R. China
| | - Li Zhu
- School of Life Sciences, Lanzhou University, Lanzhou, P.R. China
| | - Xi Lan
- MOE Key Laboratory of Environment and Genes Related to Diseases, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China
| | - Duan-Wei Zhao
- Gansu Provincial Institute of Drug Control, Lanzhou, P.R. China
| | - Yong-Jun He
- School of Medicine, Xizang Minzu University, Xian' yang, Shaanxi, P.R. China
| | - Zheng-Qi Sun
- School of Medicine, Xizang Minzu University, Xian' yang, Shaanxi, P.R. China
| | - Di Wu
- School of Life Sciences, Lanzhou University, Lanzhou, P.R. China
| | - Hai-Yun Li
- MOE Key Laboratory of Environment and Genes Related to Diseases, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China.
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10
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Farag NS, Breitinger U, Breitinger HG, El Azizi MA. Viroporins and inflammasomes: A key to understand virus-induced inflammation. Int J Biochem Cell Biol 2020; 122:105738. [PMID: 32156572 PMCID: PMC7102644 DOI: 10.1016/j.biocel.2020.105738] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 02/07/2023]
Abstract
The article provides a summary on cellular receptors involved in virus immunity. It summarizes key findings on viroporins, a novel class of viral proteins and their role in the virus life cycle and host cell interactions. It presents an overview of the current understanding of inflammasomes complex activation, with special focus on NLRP3. It discusses the correlation between viroporins and inflammasomes activation and aggravated inflammatory cytokines production.
Viroporins are virus encoded proteins that alter membrane permeability and can trigger subsequent cellular signals. Oligomerization of viroporin subunits results in formation of a hydrophilic pore which facilitates ion transport across host cell membranes. These viral channel proteins may be involved in different stages of the virus infection cycle. Inflammasomes are large multimolecular complexes best recognized for their ability to control activation of caspase-1, which in turn regulates the maturation of interleukin-1 β (IL-1β) and interleukin 18 (IL-18). IL-1β was originally identified as a pro-inflammatory cytokine able to induce both local and systemic inflammation and a febrile reaction in response to infection or injury. Excessive production of IL-1β is associated with autoimmune and inflammatory diseases. Microbial derivatives, bacterial pore-forming toxins, extracellular ATP and other pathogen-associated molecular patterns trigger activation of NLRP3 inflammasomes. Recent studies have reported that viroporin activity is capable of inducing inflammasome activity and production of IL-1β, where NLRP3 is shown to be regulated by fluxes of K+, H+ and Ca2+ in addition to reactive oxygen species, autophagy and endoplasmic reticulum stress. The aim of this review is to present an overview of the key findings on viroporin activity with special emphasis on their role in virus immunity and as possible activators of inflammasomes.
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Affiliation(s)
- N S Farag
- Department of Microbiology and Immunology, German University inCairo, New Cairo, Egypt.
| | - U Breitinger
- Department of Biochemistry, German University in Cairo, New Cairo, Egypt
| | - H G Breitinger
- Department of Biochemistry, German University in Cairo, New Cairo, Egypt
| | - M A El Azizi
- Department of Microbiology and Immunology, German University inCairo, New Cairo, Egypt
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11
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Suades A, Alcaraz A, Cruz E, Álvarez-Marimon E, Whitelegge JP, Manyosa J, Cladera J, Perálvarez-Marín A. Structural biology workflow for the expression and characterization of functional human sodium glucose transporter type 1 in Pichia pastoris. Sci Rep 2019; 9:1203. [PMID: 30718602 PMCID: PMC6362292 DOI: 10.1038/s41598-018-37445-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 12/04/2018] [Indexed: 12/24/2022] Open
Abstract
Heterologous expression of human membrane proteins is a challenge in structural biology towards drug discovery. Here we report a complete expression and purification process of a functional human sodium/D-glucose co-transporter 1 (hSGLT1) in Pichia pastoris as representative example of a useful strategy for any human membrane protein. hSGLT1 gene was cloned in two different plasmids to develop parallel strategies: one which includes green fluorescent protein fusion for screening optimal conditions, and another for large scale protein production for structural biology and biophysics studies. Our strategy yields at least 1 mg of monodisperse purified recombinant hSGLT1 per liter of culture, which can be characterized by circular dichroism and infrared spectroscopy as an alpha-helical fold protein. This purified hSGLT1 transports co-substrates (Na+ and glucose) and it is inhibited by phlorizin in electrophysiological experiments performed in planar lipid membranes.
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Affiliation(s)
- Albert Suades
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain.,Department of Biochemistry and Biophysics, Stockholm University, SE-10691, Stockholm, Sweden
| | - Antonio Alcaraz
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, 12071, Castellón, Spain
| | - Esteban Cruz
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain
| | - Elena Álvarez-Marimon
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain
| | - Julian P Whitelegge
- The Pasarow Mass Spectrometry Laboratory, The NPI-Semel Institute, David Geffen School of Medicine, UCLA, 760 Westwood Plaza, Los Angeles, CA, 90095, USA
| | - Joan Manyosa
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain
| | - Josep Cladera
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain
| | - Alex Perálvarez-Marín
- Biophysics Unit, Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallés, Catalonia, Spain.
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12
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Molecular Characterization of the Viroporin Function of Foot-and-Mouth Disease Virus Nonstructural Protein 2B. J Virol 2018; 92:JVI.01360-18. [PMID: 30232178 DOI: 10.1128/jvi.01360-18] [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: 08/09/2018] [Accepted: 09/07/2018] [Indexed: 02/01/2023] Open
Abstract
Nonstructural protein 2B of foot-and-mouth disease (FMD) virus (FMDV) is comprised of a small, hydrophobic, 154-amino-acid protein. Structure-function analyses demonstrated that FMDV 2B is an ion channel-forming protein. Infrared spectroscopy measurements using partially overlapping peptides that spanned regions between amino acids 28 and 147 demonstrated the adoption of helical conformations in two putative transmembrane regions between residues 60 and 78 and between residues 119 and 147 and a third transmembrane region between residues 79 and 106, adopting a mainly extended structure. Using synthetic peptides, ion channel activity measurements in planar lipid bilayers and imaging of single giant unilamellar vesicles (GUVs) revealed the existence of two sequences endowed with membrane-porating activity: one spanning FMDV 2B residues 55 to 82 and the other spanning the C-terminal region of 2B from residues 99 to 147. Mapping the latter sequence identified residues 119 to 147 as being responsible for the activity. Experiments to assess the degree of insertion of the synthetic peptides in bilayers and the inclination angle adopted by each peptide regarding the membrane plane normal confirm that residues 55 to 82 and 119 to 147 of 2B actively insert as transmembrane helices. Using reverse genetics, a panel of 13 FMD recombinant mutant viruses was designed, which harbored nonconservative as well as alanine substitutions in critical amino acid residues in the area between amino acid residues 28 and 147. Alterations to any of these structures interfered with pore channel activity and the capacity of the protein to permeabilize the endoplasmic reticulum (ER) to calcium and were lethal for virus replication. Thus, FMDV 2B emerges as the first member of the viroporin family containing two distinct pore domains.IMPORTANCE FMDV nonstructural protein 2B is able to insert itself into cellular membranes to form a pore. This pore allows the passage of ions and small molecules through the membrane. In this study, we were able to show that both current and small molecules are able to pass though the pore made by 2B. We also discovered for the first time a virus with a pore-forming protein that contains two independent functional pores. By making mutations in our infectious clone of FMDV, we determined that mutations in either pore resulted in nonviable virus. This suggests that both pore-forming functions are independently required during FMDV infection.
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Classical Swine Fever Virus p7 Protein Interacts with Host Protein CAMLG and Regulates Calcium Permeability at the Endoplasmic Reticulum. Viruses 2018; 10:v10090460. [PMID: 30154321 PMCID: PMC6165257 DOI: 10.3390/v10090460] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/22/2018] [Accepted: 08/23/2018] [Indexed: 12/14/2022] Open
Abstract
We have previously shown that Classical Swine Fever Virus (CSFV) p7 is an essential nonstructural protein with a viroporin activity, a critical function in the progression of virus infection. We also identified p7 domains and amino acid residues critical for pore formation. Here, we describe how p7 specifically interacts with host protein CAMLG, an integral ER transmembrane protein involved in intracellular calcium release regulation and signal response generation. Detection of interaction as well as the identification of p7 areas mediating interaction with CAMLG was performed by yeast two-hybrid. p7-CAMLG interaction was further confirmed by confocal microscopy in eukaryotic cells, co-expressing both proteins. Mutant forms of p7 having substituted native residues identified as mediating interaction with CAMLG showed a decreased co-localization compared with the native forms of p7. Furthermore, it is shown that native p7, but not the mutated forms of p7 that fail to interact with CAMLG, efficiently mediates calcium permeability in the ER. Interestingly, viruses harboring some of those mutated forms of p7 have been previously shown to have a significantly decreased virulence in swine.
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14
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Largo E, Gladue DP, Torralba J, Aguilella VM, Alcaraz A, Borca MV, Nieva JL. Mutation-induced changes of transmembrane pore size revealed by combined ion-channel conductance and single vesicle permeabilization analyses. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1015-1021. [PMID: 29317201 DOI: 10.1016/j.bbamem.2018.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/25/2017] [Accepted: 01/04/2018] [Indexed: 02/06/2023]
Abstract
Permeabilization of the Endoplasmic Reticulum (ER) is instrumental in the progression of host-cell infection by many viral pathogens. We have described that permeabilization of ER model membranes by the pore-forming domain of the Classical Swine Fever Virus (CSFV) p7 protein depends on two sequence determinants: the C-terminal transmembrane helix, and the preceding polar loop that regulates its activity. Here, by combining ion-channel activity measurements in planar lipid bilayers with imaging of single Giant Unilamellar Vesicles (GUVs), we demonstrate that point substitutions directed to conserved residues within these regions affect ER-like membrane permeabilization following distinct mechanisms. Whereas the polar loop appeared to be involved in protein insertion and oligomerization, substitution of residues predicted to face the lumen of the pore inhibited large conducting channels (>1 nS) over smaller ones (120 pS). Quantitative analyses of the ER-GUV distribution as a function of the solute size revealed a selective inhibition for the permeation of solutes with sizes larger than 4 kDa, further demonstrating that the mutation targeting the transmembrane helix prevented formation of the large pores. Collectively, our data support the idea that the pore-forming domain of p7 may assemble into finite pores with approximate diameters of 1 and 5 nm. Moreover, the observation that the mutation interfering with formation of the larger pores can hamper virus production without affecting ER localization or homo-oligomerization, suggests prospective strategies to block/attenuate pestiviruses.
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Affiliation(s)
- Eneko Largo
- Biofisika Institute (CSIC, UPV/EHU), Biochemistry and Molecular Biology Department, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Douglas P Gladue
- Plum Island Animal Disease Center, ARS, USDA, Greenport, NY 11944, USA
| | - Johana Torralba
- Biofisika Institute (CSIC, UPV/EHU), Biochemistry and Molecular Biology Department, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Vicente M Aguilella
- Laboratory of Molecular Biophysics, Department of Physics, University Jaume I, 12071 Castellón, Spain
| | - Antonio Alcaraz
- Laboratory of Molecular Biophysics, Department of Physics, University Jaume I, 12071 Castellón, Spain
| | - Manuel V Borca
- Plum Island Animal Disease Center, ARS, USDA, Greenport, NY 11944, USA
| | - José L Nieva
- Biofisika Institute (CSIC, UPV/EHU), Biochemistry and Molecular Biology Department, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain.
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15
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He W, Xu H, Gou H, Yuan J, Liao J, Chen Y, Fan S, Xie B, Deng S, Zhang Y, Chen J, Zhao M. CSFV Infection Up-Regulates the Unfolded Protein Response to Promote Its Replication. Front Microbiol 2017; 8:2129. [PMID: 29163417 PMCID: PMC5673830 DOI: 10.3389/fmicb.2017.02129] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/18/2017] [Indexed: 01/07/2023] Open
Abstract
Classical swine fever (CSF) is an OIE-listed, highly contagious animal disease caused by classical swine fever virus (CSFV). The endoplasmic reticulum (ER) is an organelle in which the replication of many RNA viruses takes place. During viral infection, a series of events elicited in cells can destroy the ER homeostasis that cause ER stress and induce an unfolded protein response (UPR). In this study, we demonstrate that ER stress was induced during CSFV infection as several UPR-responsive elements such as XBP1(s), GRP78 and CHOP were up-regulated. Specifically, CSFV transiently activated IRE1 pathway at the initial stage of infection but rapidly switched off, likely due to the reduction in cytoplasm Ca2+ after viral incubation. Additionally, our data show that the ER stress induced by CSFV can promote CSFV production, which the IRE1 pathway play an important role in it. Evidence of ER stress in vivo was also confirmed by the marked elevation of GRP78 in CSFV-infected pig PBMC and tissues. Collectively, these data indicate that the ER stress was induced upon CSFV infection and that the activation of the IRE1 pathway benefits CSFV replication.
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Affiliation(s)
- Wencheng He
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Hailuan Xu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Hongchao Gou
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Jin Yuan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Jiedan Liao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yuming Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Shuangqi Fan
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Baoming Xie
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Shaofeng Deng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yangyi Zhang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Jinding Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Mingqiu Zhao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
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