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Kyaw A, Roepke K, Arthur T, Howard KP. Conformation of influenza AM2 membrane protein in nanodiscs and liposomes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184152. [PMID: 36948480 PMCID: PMC10175228 DOI: 10.1016/j.bbamem.2023.184152] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/15/2023] [Accepted: 03/14/2023] [Indexed: 03/24/2023]
Abstract
The influenza A M2 protein (AM2) is a multifunctional membrane-associated homotetramer that orchestrates several essential events in the viral infection cycle including viral assembly and budding. An atomic-level conformational understanding of this key player in the influenza life cycle could inform new antiviral strategies. For conformational studies of complex systems like the AM2 membrane protein, a multipronged approach using different biophysical methods and different model membranes is a powerful way to incorporate complementary data and achieve a fuller, more robust understanding of the system. However, one must be aware of how the sample composition required for a particular method impacts the data collected and how conclusions are drawn. In that spirit, we systematically compared the properties of AM2 in two different model membranes: nanodiscs and liposomes. Electron paramagnetic spectroscopy of spin-labeled AM2 showed that the conformation and dynamics were strikingly similar in both AM2-nanodiscs and AM2-liposomes consistent with similar conformations in both model membranes. Analysis of spin labeled lipids embedded in both model membranes revealed that the bilayer in AM2-liposomes was more fluid and permeable to oxygen than AM2-nanodiscs with the same lipid composition. Once the difference in the partitioning of the paramagnetic oxygen relaxation agent was taken into account, the membrane topology of AM2 appeared to be the same in both liposomes and nanodiscs. Finally, functionally relevant AM2 conformational shifts previously seen in liposomes due to the addition of cholesterol were also observed in nanodiscs.
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Affiliation(s)
- Aye Kyaw
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081, United States of America
| | - Kyra Roepke
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081, United States of America
| | - Tyrique Arthur
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081, United States of America
| | - Kathleen P Howard
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA 19081, United States of America.
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Dregni AJ, McKay MJ, Surya W, Queralt-Martin M, Medeiros-Silva J, Wang HK, Aguilella V, Torres J, Hong M. The Cytoplasmic Domain of the SARS-CoV-2 Envelope Protein Assembles into a β-Sheet Bundle in Lipid Bilayers. J Mol Biol 2023; 435:167966. [PMID: 36682677 PMCID: PMC9851921 DOI: 10.1016/j.jmb.2023.167966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/23/2022] [Accepted: 01/11/2023] [Indexed: 01/21/2023]
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) envelope (E) protein forms a pentameric ion channel in the lipid membrane of the endoplasmic reticulum Golgi intermediate compartment (ERGIC) of the infected cell. The cytoplasmic domain of E interacts with host proteins to cause virus pathogenicity and may also mediate virus assembly and budding. To understand the structural basis of these functions, here we investigate the conformation and dynamics of an E protein construct (residues 8-65) that encompasses the transmembrane domain and the majority of the cytoplasmic domain using solid-state NMR. 13C and 15N chemical shifts indicate that the cytoplasmic domain adopts a β-sheet-rich conformation that contains three β-strands separated by turns. The five subunits associate into an umbrella-shaped bundle that is attached to the transmembrane helices by a disordered loop. Water-edited NMR spectra indicate that the third β-strand at the C terminus of the protein is well hydrated, indicating that it is at the surface of the β-bundle. The structure of the cytoplasmic domain cannot be uniquely determined from the inter-residue correlations obtained here due to ambiguities in distinguishing intermolecular and intramolecular contacts for a compact pentameric assembly of this small domain. Instead, we present four structural topologies that are consistent with the measured inter-residue contacts. These data indicate that the cytoplasmic domain of the SARS-CoV-2 E protein has a strong propensity to adopt β-sheet conformations when the protein is present at high concentrations in lipid bilayers. The equilibrium between the β-strand conformation and the previously reported α-helical conformation may underlie the multiple functions of E in the host cell and in the virion.
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Affiliation(s)
- Aurelio J Dregni
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Matthew J McKay
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Wahyu Surya
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Maria Queralt-Martin
- Laboratory of Molecular Biophysics. Department of Physics. Universitat Jaume I. 12080 Castellón, Spain
| | - João Medeiros-Silva
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Harrison K Wang
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Vicente Aguilella
- Laboratory of Molecular Biophysics. Department of Physics. Universitat Jaume I. 12080 Castellón, Spain
| | - Jaume Torres
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States.
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Mao H, Cao L, Xu T, Xia X, Ren P, Han P, Li C, Hui X, Lin X, Huang K, Jin M. YWHAG inhibits influenza a virus replication by suppressing the release of viral M2 protein. Front Microbiol 2022; 13:951009. [PMID: 35928168 PMCID: PMC9343881 DOI: 10.3389/fmicb.2022.951009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 06/28/2022] [Indexed: 11/25/2022] Open
Abstract
Influenza A virus (IAV) poses a serious threat to human life and property. The IAV matrix protein 2 (M2) is significant in viral budding. Increasing studies have proven the important roles of host factors in IAV replication. In this study, immunoprecipitation combined with mass spectrometry revealed that the host protein tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein gamma (YWHAG), which belongs to the 14-3-3 protein scaffold family, interacts with M2. Their interactions were further confirmed by co-immunoprecipitation (Co-IP), immunofluorescence, and confocal microscopy of virus-infected HeLa cells. Moreover, we constructed YWHAG-KO and YWHAG-overexpressing cells and found that YWHAG knockout significantly increased viral production, whereas its overexpression reduced the titer of virus progeny. Therefore, YWHAG is a negative regulatory factor during IAV infection. Further, YWHAG knockout or overexpression had no effect on the binding, entry, or viral RNA replication in the early stages of the virus life cycle. On the contrary, it impaired the release of virions at the plasma membrane as determined using transmission electron microscopy and suppressed the M2-mediated budding of the influenza virus. Importantly, the H158F mutation of YWHAG was found to affect interaction with M2 and its budding. Collectively, our work demonstrates that YWHAG is a novel cellular regulator that targets and mediates the interaction and release of M2.
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Affiliation(s)
- Haiying Mao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan, China
| | - Lei Cao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan, China
| | - Ting Xu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan, China
| | - Xiaohan Xia
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Peilei Ren
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan, China
| | - Pengfei Han
- College of Science, Huazhong Agricultural University, Wuhan, China
| | - Chengfei Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan, China
| | - Xianfeng Hui
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan, China
| | - Xian Lin
- Chinese Academy of Sciences (CAS) Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Wuhan, China
| | - Kun Huang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan, China
- *Correspondence: Kun Huang,
| | - Meilin Jin
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan, China
- Meilin Jin,
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