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Sato R, Okura T, Kawahara M, Takizawa N, Momose F, Morikawa Y. Apical Trafficking Pathways of Influenza A Virus HA and NA via Rab17- and Rab23-Positive Compartments. Front Microbiol 2019; 10:1857. [PMID: 31456775 PMCID: PMC6700264 DOI: 10.3389/fmicb.2019.01857] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 07/29/2019] [Indexed: 11/13/2022] Open
Abstract
The envelope proteins of influenza A virus, hemagglutinin (HA) and neuraminidase (NA), play critical roles in viral entry to host cells and release from the cells, respectively. After protein synthesis, they are transported from the trans-Golgi network (TGN) to the apical plasma membrane (PM) and assembled into virus particles. However, the post-TGN transport pathways of HA and NA have not been clarified. Temporal study by confocal microscopy revealed that HA and NA colocalized soon after their synthesis, and relocated together from the TGN to the upper side of the cell. Using the Rab family protein, we investigated the post-TGN transport pathways of HA and NA. HA partially colocalized with AcGFP-Rab15, Rab17, and Rab23, but rarely with AcGFP-Rab11. When analyzed in cells stably expressing AcGFP-Rab, HA/NA colocalized with Rab15 and Rab17, markers of apical sorting and recycling endosomes, and later colocalized with Rab23, which distributes to the apical PM and endocytic vesicles. Overexpression of the dominant-negative (DN) mutants of Rab15 and Rab17, but not Rab23, significantly delayed HA transport to the PM. However, Rab23DN impaired cell surface expression of HA. Live-cell imaging revealed that NA moved rapidly with Rab17 but not with Rab15. NA also moved with Rab23 in the cytoplasm, but this motion was confined at the upper side of the cell. A fraction of HA was localized to Rab17 and Rab23 double-positive vesicles in the cytoplasm. Coimmunoprecipitation indicated that HA was associated with Rab17 and Rab23 in lipid raft fractions. When cholesterol was depleted by methyl-β-cyclodextrin treatment, the motion of NA and Rab17 signals ceased. These results suggest that HA and NA are incorporated into lipid raft microdomains and are cotransported to the PM by Rab17-positive and followed by Rab23-positive vesicles.
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Affiliation(s)
- Ryota Sato
- Graduate School for Infection Control, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Takashi Okura
- Graduate School for Infection Control, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Madoka Kawahara
- Graduate School for Infection Control, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Naoki Takizawa
- Laboratory of Basic Biology, Institute of Microbial Chemistry, Tokyo, Japan
| | - Fumitaka Momose
- Graduate School for Infection Control, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
| | - Yuko Morikawa
- Graduate School for Infection Control, Kitasato Institute for Life Sciences, Kitasato University, Tokyo, Japan
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Liu X, Ding L, Yuan J, Liao J, Duan L, Wang W, Tan W, Yu W, Zhou B, Chen X, Yang Z. Identification of a Novel Universal Potential Epitope on the Cytoplasmic Tail of H7N9 Virus Hemagglutinin. Virol Sin 2019; 34:334-337. [PMID: 31016481 DOI: 10.1007/s12250-019-00110-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 03/05/2019] [Indexed: 11/30/2022] Open
Affiliation(s)
- Xi Liu
- Department of Infectious Diseases, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, 51900, China
| | - Li Ding
- Department of Infectious Diseases, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, 51900, China
| | - Jing Yuan
- Department of Infectious Diseases, The Third People's Hospital of Shenzhen (The Second Affiliated Hospital of Southern University of Science and Technology), Shenzhen, 518000, China
| | - Jian Liao
- Shenzhen Key Laboratory of Infection and Immunity, The Third People's Hospital of Shenzhen (The Second Affiliated Hospital of Southern University of Science and Technology), Shenzhen, 518000, China
| | - Lian Duan
- Shenzhen Key Laboratory of Infection and Immunity, The Third People's Hospital of Shenzhen (The Second Affiliated Hospital of Southern University of Science and Technology), Shenzhen, 518000, China
| | - Wenfei Wang
- Department of Pathogen Biology, School of Medicine, Shenzhen University, Shenzhen, 518000, China
| | - Weiguo Tan
- Lab for Tuberculosis Research, Shenzhen Center for Chronic Disease Control, Shenzhen, 518020, China
| | - Weiye Yu
- Lab for Tuberculosis Research, Shenzhen Center for Chronic Disease Control, Shenzhen, 518020, China
| | - Boping Zhou
- Longhua Branch of Shenzhen People's Hospital, Shenzhen, 518000, China
| | - Xinchun Chen
- Department of Pathogen Biology, School of Medicine, Shenzhen University, Shenzhen, 518000, China
| | - Zheng Yang
- Lab for Tuberculosis Research, Shenzhen Center for Chronic Disease Control, Shenzhen, 518020, China. .,Shenzhen Key Laboratory of Infection and Immunity, The Third People's Hospital of Shenzhen (The Second Affiliated Hospital of Southern University of Science and Technology), Shenzhen, 518000, China.
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Palmitoylation of Sindbis Virus TF Protein Regulates Its Plasma Membrane Localization and Subsequent Incorporation into Virions. J Virol 2017; 91:JVI.02000-16. [PMID: 27852864 DOI: 10.1128/jvi.02000-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 11/13/2016] [Indexed: 01/20/2023] Open
Abstract
Palmitoylation is a reversible, posttranslational modification that helps target proteins to cellular membranes. The alphavirus small membrane proteins 6K and TF have been reported to be palmitoylated and to positively regulate budding. 6K and TF are isoforms that are identical in their N termini but unique in their C termini due to a -1 ribosomal frameshift during translation. In this study, we used cysteine (Cys) mutants to test differential palmitoylation of the Sindbis virus 6K and TF proteins. We modularly mutated the five Cys residues in the identical N termini of 6K and TF, the four additional Cys residues in TF's unique C terminus, or all nine Cys residues in TF. Using these mutants, we determined that TF palmitoylation occurs primarily in the N terminus. In contrast, 6K is not palmitoylated, even on these shared residues. In the C-terminal Cys mutant, TF protein levels increase both in the cell and in the released virion compared to the wild type. In viruses with the N-terminal Cys residues mutated, TF is much less efficiently localized to the plasma membrane, and it is not incorporated into the virion. The three Cys mutants have minor defects in cell culture growth but a high incidence of abnormal particle morphologies compared to the wild-type virus as determined by transmission electron microscopy. We propose a model where the C terminus of TF modulates the palmitoylation of TF at the N terminus, and palmitoylated TF is preferentially trafficked to the plasma membrane for virus budding. IMPORTANCE Alphaviruses are a reemerging viral cause of arthritogenic disease. Recently, the small 6K and TF proteins of alphaviruses were shown to contribute to virulence in vivo Nevertheless, a clear understanding of the molecular mechanisms by which either protein acts to promote virus infection is missing. The TF protein is a component of budded virions, and optimal levels of TF correlate positively with wild-type-like particle morphology. In this study, we show that the palmitoylation of TF regulates its localization to the plasma membrane, which is the site of alphavirus budding. Mutants in which TF is not palmitoylated display drastically reduced plasma membrane localization, which effectively prevents TF from participating in budding or being incorporated into virus particles. Investigation of the regulation of TF will aid current efforts in the alphavirus field searching for approaches to mitigate alphaviral disease in humans.
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Kordyukova L. Structural and functional specificity of Influenza virus haemagglutinin and paramyxovirus fusion protein anchoring peptides. Virus Res 2017; 227:183-199. [DOI: 10.1016/j.virusres.2016.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 02/08/2023]
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Scolari S, Imkeller K, Jolmes F, Veit M, Herrmann A, Schwarzer R. Modulation of cell surface transport and lipid raft localization by the cytoplasmic tail of the influenza virus hemagglutinin. Cell Microbiol 2015; 18:125-36. [PMID: 26243691 PMCID: PMC7162421 DOI: 10.1111/cmi.12491] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/28/2015] [Accepted: 07/13/2015] [Indexed: 11/30/2022]
Abstract
Viral glycoproteins are highly variable in their primary structure, but on the other hand feature a high functional conservation to fulfil their versatile tasks during the pathogenic life cycle. Typically, all protein domains are optimized in that indispensable functions can be assigned to small conserved motifs or even individual amino acids. The cytoplasmic tail of many viral spike proteins, although of particular relevance for the virus biology, is often only insufficiently characterized. Hemagglutinin (HA), the receptor-binding protein of the influenza virus comprises a short cytoplasmic tail of 13 amino acids that exhibits three highly conserved palmitoylation sites. However, the particular importance of these modifications and the tail in general for intracellular trafficking and lateral membrane organization remains elusive. In this study, we generated HA core proteins consisting of transmembrane domain, cytoplasmic tail and a minor part of the ectodomain, tagged with a yellow fluorescent protein. Different mutation and truncation variants of these chimeric proteins were investigated using confocal microscopy, to characterize the role of cytoplasmic tail and palmitoylation for the intracellular trafficking to plasma membrane and Golgi apparatus. In addition, we assessed raft partitioning of the variants by Foerster resonance energy transfer with an established raft marker. We revealed a substantial influence of the cytoplasmic tail length on the intracellular distribution and surface exposure of the proteins. A complete removal of the tail hampers a physiological trafficking of the protein, whereas a partial truncation can be compensated by cytoplasmic palmitoylations. Plasma membrane raft partitioning on the other hand was found to imperatively require palmitoylations, and the cysteine at position 551 turned out to be of most relevance. Our data shed further light on the tight interconnection between cytoplasmic elements and intracellular trafficking and suggest a function of HA palmitoylations in both lateral sorting and anterograde trafficking of the glycoprotein.
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Affiliation(s)
- Silvia Scolari
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Katharina Imkeller
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Fabian Jolmes
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Michael Veit
- Department of Immunology and Molecular Biology, Free University, 14163, Berlin, Germany
| | - Andreas Herrmann
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Roland Schwarzer
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany.,Department of Biological Chemistry, Weizmann Institute of Science, 76100, Rehovot, Israel
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