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Yin X, Konishi T, Horikawa K, Tanaka R, Togo Y, Noda T, Hosoi M, Tsuchida M, Kunoh T, Wada S, Nakamura T, Tsuda E, Sasaki R, Mizukami T, Hasegawa M. Structure and Function of Potential Glycosylation Sites of Dynactin-Associated Protein dynAP. Mol Biotechnol 2022; 64:611-620. [PMID: 35022995 DOI: 10.1007/s12033-021-00435-3] [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: 06/02/2021] [Accepted: 12/01/2021] [Indexed: 11/28/2022]
Abstract
Overexpression of human dynactin-associated protein (dynAP) transforms NIH3T3 cells. DynAP is a single-pass transmembrane protein with a carboxy-terminal region (amino acids 135-210) exposed to the outside of the cell possessing one potential N-glycosylation site (position 143) and a distal C-terminal region (residues 173-210) harboring a Thr/Ser-rich (T/S) cluster that may be O-glycosylated. In SDS-PAGE, dynAP migrates anomalously at ~ 45 kDa, much larger than expected (22.5 kDa) based on the amino acid composition. Using dynAP mutants, we herein showed that the T/S cluster region is responsible for the anomalous migration. The T/S cluster region is required for transport to the cytoplasmic membrane and cell transformation. We produced and purified the extracellular fragment (dynAP135-210) in secreted form and analyzed the attached glycans. Asn143 displayed complex-type glycosylation, suggesting that oligosaccharide transferase may recognize the NXT/S sequon in the secretory form, but not clearly in full-length dynAP. Core I-type O-glycosylation (Gal-GalNAc) was observed, but the mass spectrometry signal was weak, clearly indicating that further studies are needed to elucidate modifications in this region.
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Affiliation(s)
- Xiaobo Yin
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Takayuki Konishi
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Kazuo Horikawa
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Ryota Tanaka
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Yuki Togo
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Takanori Noda
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Miho Hosoi
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan.,Frontier Pharma, 1281-8 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Mie Tsuchida
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan.,Frontier Pharma, 1281-8 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Tatsuki Kunoh
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Shuichi Wada
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Toshinobu Nakamura
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Eisuke Tsuda
- Specialty Medicine Research Laboratories 1, Daiichi Sankyo Co., Ltd., 1-2-58, Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan
| | - Ryuzo Sasaki
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan.,Frontier Pharma, 1281-8 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Tamio Mizukami
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan.,Frontier Pharma, 1281-8 Tamura-cho, Nagahama, Shiga, 526-0829, Japan
| | - Makoto Hasegawa
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga, 526-0829, Japan.
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Dänicke S, Heymann AK, Oster M, Wimmers K, Tesch T, Bannert E, Bühler S, Kersten S, Frahm J, Kluess J, Kahlert S, Rothkötter HJ, Billenkamp F. Does chronic dietary exposure to the mycotoxin deoxynivalenol affect the porcine hepatic transcriptome when an acute-phase response is initiated through first or second-pass LPS challenge of the liver? Innate Immun 2021; 27:388-408. [PMID: 34338001 PMCID: PMC8419296 DOI: 10.1177/17534259211030563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The sensitivity of pigs to deoxynivalenol (DON) might be increased by systemic inflammation (SI), which also has consequences for hepatic integrity. Liver lesions and a dys-regulated gene network might hamper hepatic handling and elimination of DON whereby the way of initiation of hepatic inflammation might play an additional role. First and second-pass exposure of the liver with LPS for triggering a SI was achieved by LPS infusion via pre- or post-hepatic venous route, respectively. Each infusion group was pre-conditioned either with a control diet (0.12 mg DON/kg diet) or with a DON-contaminated diet (4.59 mg DON/kg diet) for 4 wk. Liver transcriptome was evaluated at 195 min after starting infusions. DON exposure alone failed to modulate the mRNA expression significantly. However, pre- and post-hepatic LPS challenges prompted transcriptional responses in immune and metabolic levels. The mRNAs for B-cell lymphoma 2-like protein 11 as a key factor in apoptosis and IFN-γ released by T cells were clearly up-regulated in DON-fed group infused with LPS post-hepatically. On the other hand, mRNAs for nucleotide binding oligomerization domain containing 2, IFN-α and eukaryotic translation initiation factor 2α kinase 3 as ribosomal stress sensors were exclusively up-regulated in control pigs with pre-hepatic LPS infusion. These diverse effects were traced back to differences in TLR4 signalling.
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Affiliation(s)
- Sven Dänicke
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Germany
| | - Ann-Katrin Heymann
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Germany
| | - Michael Oster
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Germany
| | - Klaus Wimmers
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Germany
| | - Tanja Tesch
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Germany
| | - Erik Bannert
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Germany
| | - Susanne Bühler
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Germany
| | - Susanne Kersten
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Germany
| | - Jana Frahm
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Germany
| | - Jeannette Kluess
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Germany
| | - Stefan Kahlert
- Institute of Anatomy, Otto-von-Guericke University Magdeburg, Germany
| | | | - Fabian Billenkamp
- Institute of Animal Nutrition, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Germany
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3
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Moustafa RI, Haddad JG, Linna L, Hanoulle X, Descamps V, Mesalam AA, Baumert TF, Duverlie G, Meuleman P, Dubuisson J, Lavie M. Functional Study of the C-Terminal Part of the Hepatitis C Virus E1 Ectodomain. J Virol 2018; 92:e00939-18. [PMID: 30068644 PMCID: PMC6158422 DOI: 10.1128/jvi.00939-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 07/26/2018] [Indexed: 12/24/2022] Open
Abstract
In the hepatitis C virus (HCV) envelope glycoproteins E1 and E2, which form a heterodimer, E2 is the receptor binding protein and the major target of neutralizing antibodies, whereas the function of E1 remains less characterized. To investigate E1 functions, we generated a series of mutants in the conserved residues of the C-terminal region of the E1 ectodomain in the context of an infectious clone. We focused our analyses on two regions of interest. The first region is located in the middle of the E1 glycoprotein (between amino acid [aa] 270 and aa 291), which contains a conserved hydrophobic sequence and was proposed to constitute a putative fusion peptide. The second series of mutants was generated in the region from aa 314 to aa 342 (the aa314-342 region), which has been shown to contain two α helices (α2 and α3) by nuclear magnetic resonance studies. Of the 22 generated mutants, 20 were either attenuated or noninfectious. Several mutations modulated the virus's dependence on claudin-1 and the scavenger receptor BI coreceptors for entry. Most of the mutations in the putative fusion peptide region affected virus assembly. Conversely, mutations in the α-helix aa 315 to 324 (315-324) residues M318, W320, D321, and M322 resulted in a complete loss of infectivity without any impact on E1E2 folding and on viral assembly. Further characterization of the W320A mutant in the HCVpp model indicated that the loss of infectivity was due to a defect in viral entry. Together, these results support a role for E1 in modulating HCV interaction with its coreceptors and in HCV assembly. They also highlight the involvement of α-helix 315-324 in a late step of HCV entry.IMPORTANCE HCV is a major public health problem worldwide. The virion harbors two envelope proteins, E1 and E2, which are involved at different steps of the viral life cycle. Whereas E2 has been extensively characterized, the function of E1 remains poorly defined. We characterized here the function of the putative fusion peptide and the region containing α helices of the E1 ectodomain, which had been previously suggested to be important for virus entry. We could confirm the importance of these regions for the virus infectivity. Interestingly, we found several residues modulating the virus's dependence on several HCV receptors, thus highlighting the role of E1 in the interaction of the virus with cellular receptors. Whereas mutations in the putative fusion peptide affected HCV infectivity and morphogenesis, several mutations in the α2-helix region led to a loss of infectivity with no effect on assembly, indicating a role of this region in virus entry.
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Affiliation(s)
- Rehab I Moustafa
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
- Department of Microbial Biotechnology, Genetic Engineering and Biotechnology Division, National Research Centre, Dokki, Cairo, Egypt
| | - Juliano G Haddad
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
- Laboratoire Microbiologie Santé et Environnement, Ecole Doctorale en Sciences et Technologie, Faculté de Santé Publique, Université Libanaise, Tripoli, Liban
| | - Lydia Linna
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Xavier Hanoulle
- University of Lille, CNRS, UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Véronique Descamps
- Equipe AGIR EA4294, Laboratoire de Virologie du Centre Hospitalier Universitaire d'Amiens, Université de Picardie Jules Verne, Amiens, France
| | - Ahmed Atef Mesalam
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
- Department of Therapeutic Chemistry, National Research Centre, Dokki, Cairo, Egypt
- Research Group Immune- and Bio-markers for Infection, Centre of Excellence for Advanced Sciences, National Research Centre, Dokki, Cairo, Egypt
| | - Thomas F Baumert
- INSERM, U1110, University of Strasbourg, Pôle Hépato-digestif-Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Gilles Duverlie
- Equipe AGIR EA4294, Laboratoire de Virologie du Centre Hospitalier Universitaire d'Amiens, Université de Picardie Jules Verne, Amiens, France
| | - Philip Meuleman
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Jean Dubuisson
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Muriel Lavie
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
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4
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Nass N, Dittmer A, Hellwig V, Lange T, Beyer JM, Leyh B, Ignatov A, Weiβenborn C, Kirkegaard T, Lykkesfeldt AE, Kalinski T, Dittmer J. Expression of transmembrane protein 26 (TMEM26) in breast cancer and its association with drug response. Oncotarget 2016; 7:38408-38426. [PMID: 27224909 PMCID: PMC5122400 DOI: 10.18632/oncotarget.9493] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/29/2016] [Indexed: 12/18/2022] Open
Abstract
We have previously shown that stromal cells desensitize breast cancer cells to the anti-estrogen fulvestrant and, along with it, downregulate the expression of TMEM26 (transmembrane protein 26). In an effort to study the function and regulation of TMEM26 in breast cancer cells, we found that breast cancer cells express non-glycosylated and N-glycosylated isoforms of the TMEM26 protein and demonstrate that N-glycosylation is important for its retention at the plasma membrane. Fulvestrant induced significant changes in expression and in the N-glycosylation status of TMEM26. In primary breast cancer, TMEM26 protein expression was higher in ERα (estrogen receptor α)/PR (progesterone receptor)-positive cancers. These data suggest that ERα is a major regulator of TMEM26. Significant changes in TMEM26 expression and N-glycosylation were also found, when MCF-7 and T47D cells acquired fulvestrant resistance. Furthermore, patients who received aromatase inhibitor treatment tend to have a higher risk of recurrence when tumoral TMEM26 protein expression is low. In addition, TMEM26 negatively regulates the expression of integrin β1, an important factor involved in endocrine resistance. Data obtained by spheroid formation assays confirmed that TMEM26 and integrin β1 can have opposite effects in breast cancer cells. These data are consistent with the hypothesis that, in ERα-positive breast cancer, TMEM26 may function as a tumor suppressor by impeding the acquisition of endocrine resistance. In contrast, in ERα-negative breast cancer, particularly triple-negative cancer, high TMEM26 expression was found to be associated with a higher risk of recurrence. This implies that TMEM26 has different functions in ERα-positive and -negative breast cancer.
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Affiliation(s)
- Norbert Nass
- Otto-von-Guericke-Universität Magdeburg, Institut für Pathologie, Magdeburg, Germany
| | - Angela Dittmer
- Klinik für Gynäkologie, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany
| | - Vicky Hellwig
- Klinik für Gynäkologie, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany
| | - Theresia Lange
- Klinik für Gynäkologie, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany
| | - Johanna Mirjam Beyer
- Klinik für Gynäkologie, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany
| | - Benjamin Leyh
- Klinik für Gynäkologie, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany
| | - Atanas Ignatov
- Otto-von-Guericke-Universität Magdeburg, Universitätsfrauenklinik, Magdeburg, Germany
| | - Christine Weiβenborn
- Otto-von-Guericke-Universität Magdeburg, Universitätsfrauenklinik, Magdeburg, Germany
| | - Tove Kirkegaard
- Breast Cancer Group, Cell Death and Metabolism, Danish Cancer Society Research Center, Copenhagen, Denmark.,Present address: Department of Surgery, Koege Hospital, Koege, Denmark
| | - Anne E Lykkesfeldt
- Breast Cancer Group, Cell Death and Metabolism, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Thomas Kalinski
- Otto-von-Guericke-Universität Magdeburg, Institut für Pathologie, Magdeburg, Germany
| | - Jürgen Dittmer
- Klinik für Gynäkologie, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany
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5
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Harada Y, Hirayama H, Suzuki T. Generation and degradation of free asparagine-linked glycans. Cell Mol Life Sci 2015; 72:2509-33. [PMID: 25772500 PMCID: PMC11113800 DOI: 10.1007/s00018-015-1881-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 02/19/2015] [Accepted: 03/05/2015] [Indexed: 10/23/2022]
Abstract
Asparagine (N)-linked protein glycosylation, which takes place in the eukaryotic endoplasmic reticulum (ER), is important for protein folding, quality control and the intracellular trafficking of secretory and membrane proteins. It is known that, during N-glycosylation, considerable amounts of lipid-linked oligosaccharides (LLOs), the glycan donor substrates for N-glycosylation, are hydrolyzed to form free N-glycans (FNGs) by unidentified mechanisms. FNGs are also generated in the cytosol by the enzymatic deglycosylation of misfolded glycoproteins during ER-associated degradation. FNGs derived from LLOs and misfolded glycoproteins are eventually merged into one pool in the cytosol and the various glycan structures are processed to a near homogenous glycoform. This article summarizes the current state of our knowledge concerning the formation and catabolism of FNGs.
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Affiliation(s)
- Yoichiro Harada
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan
| | - Hiroto Hirayama
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan
| | - Tadashi Suzuki
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan
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6
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Bas T, Gao GY, Lvov A, Chandrasekhar KD, Gilmore R, Kobertz WR. Post-translational N-glycosylation of type I transmembrane KCNE1 peptides: implications for membrane protein biogenesis and disease. J Biol Chem 2011; 286:28150-9. [PMID: 21676880 DOI: 10.1074/jbc.m111.235168] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
N-Glycosylation of membrane proteins is critical for their proper folding, co-assembly and subsequent matriculation through the secretory pathway. Here, we examine the kinetics of N-glycan addition to type I transmembrane KCNE1 K(+) channel β-subunits, where point mutations that prevent N-glycosylation at one consensus site give rise to disorders of the cardiac rhythm and congenital deafness. We show that KCNE1 has two distinct N-glycosylation sites: a typical co-translational site and a consensus site ∼20 residues away that unexpectedly acquires N-glycans after protein synthesis (post-translational). Mutations that ablate the co-translational site concomitantly reduce glycosylation at the post-translational site, resulting in unglycosylated KCNE1 subunits that cannot reach the cell surface with their cognate K(+) channel. This long range inhibition is highly specific for post-translational N-glycosylation because mutagenic conversion of the KCNE1 post-translational site into a co-translational site restored both monoglycosylation and anterograde trafficking. These results directly explain how a single point mutation can prevent N-glycan attachment at multiple sites, providing a new biogenic mechanism for human disease.
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Affiliation(s)
- Tuba Bas
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605-2324, USA
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7
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Krol E, Wandzik I, Szeja W, Grynkiewicz G, Szewczyk B. In vitro antiviral activity of some uridine derivatives of 2-deoxy sugars against classical swine fever virus. Antiviral Res 2010; 86:154-62. [DOI: 10.1016/j.antiviral.2010.02.314] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 01/20/2010] [Accepted: 02/05/2010] [Indexed: 01/05/2023]
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8
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Belzhelarskaya SN, Koroleva NN, Popenko VV, Drutza VL, Orlova OV, Rubtzov PM, Kochetkov SN. Hepatitis C virus structural proteins and virus-like particles produced in recombinant baculovirus-infected insect cells. Mol Biol 2010. [DOI: 10.1134/s0026893310010139] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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9
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Naturally occurring hepatitis C virus subgenomic deletion mutants replicate efficiently in Huh-7 cells and are trans-packaged in vitro to generate infectious defective particles. J Virol 2009; 83:9079-93. [PMID: 19587042 DOI: 10.1128/jvi.00308-09] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Naturally occurring hepatitis C virus (HCV) subgenomic RNAs have been found in several HCV patients. These subgenomic deletion mutants, mostly lacking the genes encoding envelope glycoproteins, were found in both liver and serum, where their relatively high abundance suggests that they are capable of autonomous replication and can be packaged and secreted in viral particles, presumably harboring the envelope proteins from wild type virus coinfecting the same cell. We recapitulated some of these natural subgenomic deletions in the context of the isolate JFH-1 and confirmed these hypotheses in vitro. In Huh-7.5 cells, these deletion-containing genomes show robust replication and can be efficiently trans-packaged and infect naïve Huh-7.5 cells when cotransfected with the full-length wild-type J6/JFH genome. The genome structure of these natural subgenomic deletion mutants was dissected, and the maintenance of both core and NS2 regions was proven to be significant for efficient replication and trans-packaging. To further explore the requirements needed to achieve trans-complementation, we provided different combinations of structural proteins in trans. Optimal trans-complementation was obtained when fragments of the polyprotein encompassing core to p7 or E1 to NS2 were expressed. Finally, we generated a stable helper cell line, constitutively expressing the structural proteins from core to p7, which efficiently supports trans-complementation of a subgenomic deletion encompassing amino acids 284 to 732. This cell line can produce and be infected by defective particles, thus representing a powerful tool to investigate the life cycle and relevance of natural HCV subgenomic deletion mutants in vivo.
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10
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Ruiz-Canada C, Kelleher DJ, Gilmore R. Cotranslational and posttranslational N-glycosylation of polypeptides by distinct mammalian OST isoforms. Cell 2009; 136:272-83. [PMID: 19167329 DOI: 10.1016/j.cell.2008.11.047] [Citation(s) in RCA: 292] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 10/17/2008] [Accepted: 11/25/2008] [Indexed: 02/01/2023]
Abstract
Asparagine-linked glycosylation of polypeptides in the lumen of the endoplasmic reticulum is catalyzed by the hetero-oligomeric oligosaccharyltransferase (OST). OST isoforms with different catalytic subunits (STT3A versus STT3B) and distinct enzymatic properties are coexpressed in mammalian cells. Using siRNA to achieve isoform-specific knockdowns, we show that the OST isoforms cooperate and act sequentially to mediate protein N-glycosylation. The STT3A OST isoform is primarily responsible for cotranslational glycosylation of the nascent polypeptide as it enters the lumen of the endoplasmic reticulum. The STT3B isoform is required for efficient cotranslational glycosylation of an acceptor site adjacent to the N-terminal signal sequence of a secreted protein. Unlike STT3A, STT3B efficiently mediates posttranslational glycosylation of a carboxyl-terminal glycosylation site in an unfolded protein. These distinct and complementary roles for the OST isoforms allow sequential scanning of polypeptides for acceptor sites to insure the maximal efficiency of N-glycosylation.
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Affiliation(s)
- Catalina Ruiz-Canada
- Department of Biochemistry and Molecular Pharmacology University of Massachusetts Medical School, Worcester, MA 01605, USA
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11
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Lambert C, Prange R. Posttranslational N-glycosylation of the hepatitis B virus large envelope protein. Virol J 2007; 4:45. [PMID: 17537250 PMCID: PMC1891283 DOI: 10.1186/1743-422x-4-45] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2007] [Accepted: 05/30/2007] [Indexed: 11/25/2022] Open
Abstract
Background The addition of N-linked glycans to proteins is normally a cotranslational process that occurs during translocation of the nascent protein to the endoplasmic reticulum. Here, we report on an exception to this rule occurring on the hepatitis B virus (HBV) large L envelope protein that is a subject to co-plus posttranslational N-glycosylation. Results By using an improved detection system, we identified so far unrecognized, novel isoforms of L. Based on mutational analyses, the use of N-glycosylation inhibitors, and pulse-chase studies, we showed that these isoforms are due to posttranslational N-glycan addition to the asparagines 4 and 112 within the preS domain of L. While an inhibition of N-glycosylation and glycan trimming profoundly blocked virus assembly and release, the posttranslational N-glycosylation of L itself was found to be dispensable for HBV morphogenesis. Conclusion These data together with previous results implicate that the N-glycosylation requirements of virion release are due to functional inhibition of cell glycoproteins engaged by HBV.
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Affiliation(s)
- Carsten Lambert
- Institute for Medical Microbiology and Hygiene, University of Mainz, Augustusplatz, D-55101 Mainz, Germany
| | - Reinhild Prange
- Institute for Medical Microbiology and Hygiene, University of Mainz, Augustusplatz, D-55101 Mainz, Germany
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12
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Gam LH, Leow CH, Man CN, Gooi BH, Singh M. Analysis of differentially expressed proteins in cancerous and normal colonic tissues. World J Gastroenterol 2006; 12:4973-80. [PMID: 16937492 PMCID: PMC4087399 DOI: 10.3748/wjg.v12.i31.4973] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To identify and analyze the differentially expressed proteins in normal and cancerous tissues of four patients suffering from colon cancer.
METHODS: Colon tissues (normal and cancerous) were homogenized and the proteins were extracted using three protein extraction buffers. The extraction buffers were used in an orderly sequence of increasing extraction strength for proteins with hydrophobic properties. The protein extracts were separated using the SDS-PAGE method and the images were captured and analyzed using Quantity One software. The target protein bands were subjected to in-gel digestion with trypsin and finally analyzed using an ESI-ion trap mass spectrometer.
RESULTS: A total of 50 differentially expressed proteins in colonic cancerous and normal tissues were identified.
CONCLUSION: Many of the identified proteins have been reported to be involved in the progression of similar or other types of cancers. However, some of the identified proteins have not been reported before. In addition, a number of hypothetical proteins were also identified.
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Affiliation(s)
- Lay-Harn Gam
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.
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13
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Owsianka A, Tarr AW, Juttla VS, Lavillette D, Bartosch B, Cosset FL, Ball JK, Patel AH. Monoclonal antibody AP33 defines a broadly neutralizing epitope on the hepatitis C virus E2 envelope glycoprotein. J Virol 2005; 79:11095-104. [PMID: 16103160 PMCID: PMC1193588 DOI: 10.1128/jvi.79.17.11095-11104.2005] [Citation(s) in RCA: 234] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Accepted: 06/01/2005] [Indexed: 02/03/2023] Open
Abstract
Hepatitis C virus (HCV) remains a significant threat to the general health of the world's population, and there is a pressing need for the development of new treatments and preventative vaccines. Here, we describe the generation of retrovirus-based pseudoparticles (HCVpp) incorporating a panel of full-length E1E2 clones representative of the major genotypes 1 through 6, and their application to assess the reactivity and neutralizing capability of antisera and monoclonal antibodies raised against portions of the HCV E2 envelope protein. Rabbit antisera raised against either the first hypervariable region or ectodomain of E2 showed limited and strain specific neutralization. By contrast, the monoclonal antibody (MAb) AP33 demonstrated potent neutralization of infectivity against HCVpp carrying E1E2 representative of all genotypes tested. The concentration of AP33 required to achieve 50% inhibition of infection by HCVpp of diverse genotypes ranged from 0.6 to 32 mug/ml. The epitope recognized by MAb AP33 is linear and highly conserved across different genotypes of HCV. Thus, identification of a broadly neutralizing antibody that recognizes a linear epitope is likely to be of significant benefit to future vaccine and therapeutic antibody development.
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Affiliation(s)
- Ania Owsianka
- MRC Virology Unit, Institute of Virology, University of Glasgow, UK
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14
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Goffard A, Callens N, Bartosch B, Wychowski C, Cosset FL, Montpellier C, Dubuisson J. Role of N-linked glycans in the functions of hepatitis C virus envelope glycoproteins. J Virol 2005; 79:8400-9. [PMID: 15956584 PMCID: PMC1143753 DOI: 10.1128/jvi.79.13.8400-8409.2005] [Citation(s) in RCA: 201] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hepatitis C virus (HCV) encodes two viral envelope glycoproteins. E1 contains 4 or 5 N-linked glycosylation sites and E2 contains up to 11, with most of the sites being well conserved, suggesting that they play an essential role in some functions of these proteins. For this study, we used retroviral pseudotyped particles harboring mutated HCV envelope glycoproteins to study these glycans. The mutants were named with an N followed by a number related to the relative position of the potential glycosylation site in each glycoprotein (E1N1 to E1N4 for E1 mutants and E2N1 to E2N11 for E2 mutants). The characterization of these mutants allowed us to define three phenotypes. For the first group (E1N3, E2N3, E2N5, E2N6, E2N7, and E2N9), the infectivities of the mutants were close to that of the wild type. The second group (E1N1, E1N2, E1N4, E2N1, and E2N11) contained mutants that were still infectious but whose infectivities were reduced to <50% that of the wild type. The third group (E2N2, E2N4, E2N8, and E2N10) contained mutants that had almost totally lost infectivity. The absence of infectivity of the E2N8 and E2N10 mutants was due to the lack of incorporation of the E1E2 heterodimer into HCVpp, which was due to misfolding of the heterodimer, as shown by immunoprecipitation with conformation-sensitive antibodies and by a CD81 pull-down assay. The absence of infectivity of the E2N2 and E2N4 mutants indicated that these two glycans are involved in controlling HCV entry. Altogether, the data indicate that some glycans of HCV envelope glycoproteins play a major role in protein folding and others play a role in HCV entry.
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Affiliation(s)
- Anne Goffard
- CNRS-UPR2511, Institut de Biologie de Lille, France
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15
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Maggioni C, Braakman I. Synthesis and quality control of viral membrane proteins. Curr Top Microbiol Immunol 2005; 285:175-98. [PMID: 15609504 DOI: 10.1007/3-540-26764-6_6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Viruses use the host cellular machinery to translate viral proteins. Similar to cellular proteins directed to the secretory pathway, viral (glyco)proteins are synthesized on polyribosomes and targeted to the endoplasmic reticulum (ER). For viruses that encode polyproteins, folding of the individual proteins of the precursor often is coordinated. Translocation and the start of folding coincide and are assisted by cellular folding factors present in the lumen of the ER. The protein concentration a newborn protein finds in this compartment is enormous (hundreds of mg/ml) and the action of molecular chaperones is essential to prevent aggregation. Viral envelope proteins also undergo the cellular quality control mechanisms, which ensure, with variable stringency, that only proteins with the correct structure will proceed through the secretory pathway. Proteins that are misfolded, or not yet folded, are retained in the ER until they reach the native conformation or until their retrotranslocation into the cytosol for degradation. Peculiar characteristic of viruses is their ability to interfere with the cellular machinery to ensure virus production and, moreover, to pass through the body unobserved by the host immune system. This section describes some mechanisms of genetic variation and viral immune evasion that involve the secretory pathway.
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Affiliation(s)
- C Maggioni
- University of Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands
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16
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Bolt G, Kristensen C, Steenstrup TD. Posttranslational N-glycosylation takes place during the normal processing of human coagulation factor VII. Glycobiology 2004; 15:541-7. [PMID: 15616124 DOI: 10.1093/glycob/cwi032] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
N-glycosylation is normally a cotranslational process that occurs during translocation of the nascent protein to the endoplasmic reticulum. In the present study, however, we demonstrate posttranslational N-glycosylation of recombinant human coagulation factor VII (FVII) in CHO-K1 and 293A cells. Human FVII has two N-glycosylation sites (N145 and N322). Pulse-chase labeled intracellular FVII migrated as two bands corresponding to FVII with one and two N-glycans, respectively. N-glycosidase treatment converted both of these band into a single band, which comigrated with mutated FVII without N-glycans. Immediately after pulse, most labeled intracellular FVII had one N-glycan, but during a 1-h chase, the vast majority was processed into FVII with two N-glycans, demonstrating posttranslational N-glycosylation of FVII. Pulse-chase analysis of N-glycosylation site knockout mutants demonstrated cotranslational glycosylation of N145 but primarily or exclusively posttranslational glycosylation of N322. The posttranslational N-glycosylation appeared to take place in the same time frame as the folding of nascent FVII into a secretion-competent conformation, indicating a link between the two processes. We propose that the cotranslational conformation(s) of FVII are unfavorable for glycosylation at N332, whereas a more favorable conformation is obtained during the posttranslational folding. This is the first documentation of posttranslational N-glycosylation of a non-modified protein in mammalian cells with an intact N-glycosylation machinery. Thus, the present study demonstrates that posttranslational N-glycosylation can be a part of the normal processing of glycoproteins.
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Affiliation(s)
- Gert Bolt
- Mammalian Cell Technology, Novo Nordisk A/S, Novo Allé, 2880 Bagsvaerd, Denmark.
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17
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Abstract
Enveloped viruses are surrounded by a membrane derived from the host-cell that contains proteins called "envelope proteins". These proteins play a major role in virus assembly and entry. In most of the enveloped viruses, they are modified by N-linked glycosylation which is supposed to play a role in their stability, antigenicity and biological functions. Glycosylation is also known to play a major role in the biogenesis of proteins by being directly and/or indirectly involved in protein folding. Recent studies on hepatitis C virus (HCV) envelope proteins have revealed a complex interplay between cleavage by signal peptidase, folding and glycosylation. The knowledge that has been accumulated on the early steps of glycosylation of these proteins is presented in this review.
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Affiliation(s)
- Anne Goffard
- CNRS-UPR2511, Institut de Biologie de Lille, Institut Pasteur de Lille, Lille, France
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