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Wang T, Wang C, Wang J, Wang B. An Intrabody against B-Cell Receptor-Associated Protein 31 (BAP31) Suppresses the Glycosylation of the Epithelial Cell-Adhesion Molecule (EpCAM) via Affecting the Formation of the Sec61-Translocon-Associated Protein (TRAP) Complex. Int J Mol Sci 2023; 24:14787. [PMID: 37834237 PMCID: PMC10572819 DOI: 10.3390/ijms241914787] [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: 07/31/2023] [Revised: 09/12/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023] Open
Abstract
The epithelial cell-adhesion molecule (EpCAM) is hyperglycosylated in carcinoma tissue and the oncogenic function of EpCAM primarily depends on the degree of glycosylation. Inhibiting EpCAM glycosylation is expected to have an inhibitory effect on cancer. We analyzed the relationship of BAP31 with 84 kinds of tumor-associated antigens and found that BAP31 is positively correlated with the protein level of EpCAM. Triple mutations of EpCAM N76/111/198A, which are no longer modified by glycosylation, were constructed to determine whether BAP31 has an effect on the glycosylation of EpCAM. Plasmids containing different C-termini of BAP31 were constructed to identify the regions of BAP31 that affects EpCAM glycosylation. Antibodies against BAP31 (165-205) were screened from a human phage single-domain antibody library and the effect of the antibody (VH-F12) on EpCAM glycosylation and anticancer was investigated. BAP31 increases protein levels of EpCAM by promoting its glycosylation. The amino acid region from 165 to 205 in BAP31 plays an important role in regulating the glycosylation of EpCAM. The antibody VH-F12 significantly inhibited glycosylation of EpCAM which, subsequently, reduced the adhesion of gastric cancer cells, inducing cytotoxic autophagy, inhibiting the AKT-PI3K-mTOR signaling pathway, and, finally, resulting in proliferation inhibition both in vitro and in vivo. Finally, we clarified that BAP31 plays a key role in promoting N-glycosylation of EpCAM by affecting the Sec61 translocation channels. Altogether, these data implied that BAP31 regulates the N-glycosylation of EpCAM and may represent a potential therapeutic target for cancer therapy.
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Affiliation(s)
| | | | | | - Bing Wang
- College of Life Science and Health, Northeastern University, 195 Chuangxin Road, Hunnan District, Shenyang 110819, China; (T.W.); (C.W.); (J.W.)
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2
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Adams BM, Canniff NP, Guay KP, Larsen ISB, Hebert DN. Quantitative glycoproteomics reveals cellular substrate selectivity of the ER protein quality control sensors UGGT1 and UGGT2. eLife 2020; 9:e63997. [PMID: 33320095 PMCID: PMC7771966 DOI: 10.7554/elife.63997] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022] Open
Abstract
UDP-glucose:glycoprotein glucosyltransferase (UGGT) 1 and 2 are central hubs in the chaperone network of the endoplasmic reticulum (ER), acting as gatekeepers to the early secretory pathway, yet little is known about their cellular clients. These two quality control sensors control lectin chaperone binding and glycoprotein egress from the ER. A quantitative glycoproteomics strategy was deployed to identify cellular substrates of the UGGTs at endogenous levels in CRISPR-edited HEK293 cells. The 71 UGGT substrates identified were mainly large multidomain and heavily glycosylated proteins when compared to the general N-glycoproteome. UGGT1 was the dominant glucosyltransferase with a preference toward large plasma membrane proteins whereas UGGT2 favored the modification of smaller, soluble lysosomal proteins. This study sheds light on differential specificities and roles of UGGT1 and UGGT2 and provides insight into the cellular reliance on the carbohydrate-dependent chaperone system to facilitate proper folding and maturation of the cellular N-glycoproteome.
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Affiliation(s)
- Benjamin M Adams
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| | - Nathan P Canniff
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| | - Kevin P Guay
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
| | - Ida Signe Bohse Larsen
- Department of Cellular and Molecular Medicine, University of CopenhagenCopenhagenDenmark
- Copenhagen Center for Glycomics, University of CopenhagenCopenhagenDenmark
| | - Daniel N Hebert
- Department of Biochemistry and Molecular Biology, University of MassachusettsAmherstUnited States
- Program in Molecular and Cellular Biology, University of MassachusettsAmherstUnited States
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3
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Huang C, Suzuki T. The occurrence of nonglycosylated forms of
N
‐glycoprotein upon proteasome inhibition does not confirm cytosolic deglycosylation. FEBS Lett 2020; 594:1433-1442. [DOI: 10.1002/1873-3468.13734] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/20/2019] [Accepted: 01/06/2020] [Indexed: 11/07/2022]
Affiliation(s)
- Chengcheng Huang
- Glycometabolic Biochemistry Laboratory RIKEN Cluster for Pioneering Research Wako Japan
| | - Tadashi Suzuki
- Glycometabolic Biochemistry Laboratory RIKEN Cluster for Pioneering Research Wako Japan
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4
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Shrimal S, Cherepanova NA, Mandon EC, Venev SV, Gilmore R. Asparagine-linked glycosylation is not directly coupled to protein translocation across the endoplasmic reticulum in Saccharomyces cerevisiae. Mol Biol Cell 2019; 30:2626-2638. [PMID: 31433728 PMCID: PMC6761772 DOI: 10.1091/mbc.e19-06-0330] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Mammalian cells express two oligosaccharyltransferase complexes, STT3A and STT3B, that have distinct roles in N-linked glycosylation. The STT3A complex interacts directly with the protein translocation channel to mediate glycosylation of proteins using an N-terminal-to-C-terminal scanning mechanism. N-linked glycosylation of proteins in budding yeast has been assumed to be a cotranslational reaction. We have compared glycosylation of several glycoproteins in yeast and mammalian cells. Prosaposin, a cysteine-rich protein that contains STT3A-dependent glycosylation sites, is poorly glycosylated in yeast cells and STT3A-deficient human cells. In contrast, a protein with extreme C-terminal glycosylation sites was efficiently glycosylated in yeast by a posttranslocational mechanism. Posttranslocational glycosylation was also observed for carboxypeptidase Y-derived reporter proteins that contain closely spaced acceptor sites. A comparison of two recent protein structures indicates that the yeast OST is unable to interact with the yeast heptameric Sec complex via an evolutionarily conserved interface due to occupation of the OST binding site by the Sec63 protein. The efficiency of glycosylation in yeast is not enhanced for proteins that are translocated by the Sec61 or Ssh1 translocation channels instead of the Sec complex. We conclude that N-linked glycosylation and protein translocation are not directly coupled in yeast cells.
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Affiliation(s)
- Shiteshu Shrimal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Natalia A Cherepanova
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Elisabet C Mandon
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Sergey V Venev
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
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5
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Bousfield GR, Harvey DJ. Follicle-Stimulating Hormone Glycobiology. Endocrinology 2019; 160:1515-1535. [PMID: 31127275 PMCID: PMC6534497 DOI: 10.1210/en.2019-00001] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/16/2019] [Indexed: 01/13/2023]
Abstract
FSH glycosylation varies in two functionally important aspects: microheterogeneity, resulting from oligosaccharide structure variation, and macroheterogeneity, arising from partial FSHβ subunit glycosylation. Although advances in mass spectrometry permit extensive characterization of FSH glycan populations, microheterogeneity remains difficult to illustrate, and comparisons between different studies are challenging because no standard format exists for rendering oligosaccharide structures. FSH microheterogeneity is illustrated using a consistent glycan diagram format to illustrate the large array of structures associated with one hormone. This is extended to commercially available recombinant FSH preparations, which exhibit greatly reduced microheterogeneity at three of four glycosylation sites. Macroheterogeneity is demonstrated by electrophoretic mobility shifts due to the absence of FSHβ glycans that can be assessed by Western blotting of immunopurified FSH. Initially, macroheterogeneity was hoped to matter more than microheterogeneity. However, it now appears that both forms of carbohydrate heterogeneity have to be taken into consideration. FSH glycosylation can reduce its apparent affinity for its cognate receptor by delaying initial interaction with the receptor and limiting access to all of the available binding sites. This is followed by impaired cellular signaling responses that may be related to reduced receptor occupancy or biased signaling. To resolve these alternatives, well-characterized FSH glycoform preparations are necessary.
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Affiliation(s)
- George R Bousfield
- Department of Biological Sciences, Wichita State University, Wichita, Kansas
- Correspondence: George R. Bousfield, PhD, Department of Biological Sciences, Wichita State University, 1845 Fairmount Street, Wichita, Kansas 67260. E-mail: ; or David J. Harvey, DSc, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford. Roosevelt Drive, Oxford OX3 7FZ, United Kingdom. E-mail:
| | - David J Harvey
- Target Discovery Institute, Nuffield Department of Medicine, Oxford University, Oxford, United Kingdom
- Correspondence: George R. Bousfield, PhD, Department of Biological Sciences, Wichita State University, 1845 Fairmount Street, Wichita, Kansas 67260. E-mail: ; or David J. Harvey, DSc, Target Discovery Institute, Nuffield Department of Medicine, University of Oxford. Roosevelt Drive, Oxford OX3 7FZ, United Kingdom. E-mail:
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6
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Brasil S, Pascoal C, Francisco R, Marques-da-Silva D, Andreotti G, Videira PA, Morava E, Jaeken J, Dos Reis Ferreira V. CDG Therapies: From Bench to Bedside. Int J Mol Sci 2018; 19:ijms19051304. [PMID: 29702557 PMCID: PMC5983582 DOI: 10.3390/ijms19051304] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/14/2018] [Accepted: 04/21/2018] [Indexed: 12/20/2022] Open
Abstract
Congenital disorders of glycosylation (CDG) are a group of genetic disorders that affect protein and lipid glycosylation and glycosylphosphatidylinositol synthesis. More than 100 different disorders have been reported and the number is rapidly increasing. Since glycosylation is an essential post-translational process, patients present a large range of symptoms and variable phenotypes, from very mild to extremely severe. Only for few CDG, potentially curative therapies are being used, including dietary supplementation (e.g., galactose for PGM1-CDG, fucose for SLC35C1-CDG, Mn2+ for TMEM165-CDG or mannose for MPI-CDG) and organ transplantation (e.g., liver for MPI-CDG and heart for DOLK-CDG). However, for the majority of patients, only symptomatic and preventive treatments are in use. This constitutes a burden for patients, care-givers and ultimately the healthcare system. Innovative diagnostic approaches, in vitro and in vivo models and novel biomarkers have been developed that can lead to novel therapeutic avenues aiming to ameliorate the patients’ symptoms and lives. This review summarizes the advances in therapeutic approaches for CDG.
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Affiliation(s)
- Sandra Brasil
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
| | - Carlota Pascoal
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Research Unit on Applied Molecular Biosciences (UCIBIO), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Lisboa, Portugal.
| | - Rita Francisco
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Research Unit on Applied Molecular Biosciences (UCIBIO), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Lisboa, Portugal.
| | - Dorinda Marques-da-Silva
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Research Unit on Applied Molecular Biosciences (UCIBIO), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Lisboa, Portugal.
| | - Giuseppina Andreotti
- Istituto di Chimica Biomolecolare-Consiglio Nazionale delle Ricerche (CNR), 80078 Pozzuoli, Italy.
| | - Paula A Videira
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Research Unit on Applied Molecular Biosciences (UCIBIO), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Lisboa, Portugal.
| | - Eva Morava
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA.
| | - Jaak Jaeken
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Center for Metabolic Diseases, Universitaire Ziekenhuizen (UZ) and Katholieke Universiteit (KU) Leuven, 3000 Leuven, Belgium.
| | - Vanessa Dos Reis Ferreira
- Portuguese Association for Congenital Disorders of Glycosylation (CDG), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
- Professionals and Patient Associations International Network (CDG & Allies-PPAIN), Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2820-287 Lisboa, Portugal.
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7
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Shrimal S, Cherepanova NA, Gilmore R. DC2 and KCP2 mediate the interaction between the oligosaccharyltransferase and the ER translocon. J Cell Biol 2017; 216:3625-3638. [PMID: 28860277 PMCID: PMC5674889 DOI: 10.1083/jcb.201702159] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/29/2017] [Accepted: 07/27/2017] [Indexed: 12/21/2022] Open
Abstract
The STT3A isoform of the oligosaccharyltransferase is adjacent to the protein translocation channel to catalyze co-translational N-glycosylation of proteins in the endoplasmic reticulum. Shrimal et al. show that the DC2 and KCP2 subunits of the STT3A isoform of the oligosaccharyltransferase are responsible for mediating the interaction between the STT3A complex and the protein translocation channel to allow co-translational N-glycosylation of proteins. In metazoan organisms, the STT3A isoform of the oligosaccharyltransferase is localized adjacent to the protein translocation channel to catalyze co-translational N-linked glycosylation of proteins in the endoplasmic reticulum. The mechanism responsible for the interaction between the STT3A complex and the translocation channel has not been addressed. Using genetically modified human cells that are deficient in DC2 or KCP2 proteins, we show that loss of DC2 causes a defect in co-translational N-glycosylation of proteins that mimics an STT3A−/− phenotype. Biochemical analysis showed that DC2 and KCP2 are responsible for mediating the interaction between the protein translocation channel and the STT3A complex. Importantly, DC2- and KCP2-deficient STT3A complexes are stable and enzymatically active. Deletion mutagenesis revealed that a conserved motif in the C-terminal tail of DC2 is critical for assembly into the STT3A complex, whereas the lumenal loop and the N-terminal cytoplasmic segment are necessary for the functional interaction between the STT3A and Sec61 complexes.
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Affiliation(s)
- Shiteshu Shrimal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA
| | - Natalia A Cherepanova
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA
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Dengue Virus Hijacks a Noncanonical Oxidoreductase Function of a Cellular Oligosaccharyltransferase Complex. mBio 2017; 8:mBio.00939-17. [PMID: 28720733 PMCID: PMC5516256 DOI: 10.1128/mbio.00939-17] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dengue virus (DENV) is the most common arboviral infection globally, infecting an estimated 390 million people each year. We employed a genome-wide clustered regularly interspaced short palindromic repeat (CRISPR) screen to identify host dependency factors required for DENV propagation and identified the oligosaccharyltransferase (OST) complex as an essential host factor for DENV infection. Mammalian cells express two OSTs containing either STT3A or STT3B. We found that the canonical catalytic function of the OSTs as oligosaccharyltransferases is not necessary for DENV infection, as cells expressing catalytically inactive STT3A or STT3B are able to support DENV propagation. However, the OST subunit MAGT1, which associates with STT3B, is also required for DENV propagation. MAGT1 expression requires STT3B, and a catalytically inactive STT3B also rescues MAGT1 expression, supporting the hypothesis that STT3B serves to stabilize MAGT1 in the context of DENV infection. We found that the oxidoreductase CXXC active site motif of MAGT1 was necessary for DENV propagation, as cells expressing an AXXA MAGT1 mutant were unable to support DENV infection. Interestingly, cells expressing single-cysteine CXXA or AXXC mutants of MAGT1 were able to support DENV propagation. Utilizing the engineered peroxidase APEX2, we demonstrate the close proximity between MAGT1 and NS1 or NS4B during DENV infection. These results reveal that the oxidoreductase activity of the STT3B-containing OST is necessary for DENV infection, which may guide the development of antiviral agents targeting DENV. The host oligosaccharyltransferase (OST) complexes have been identified as essential host factors for dengue virus (DENV) replication; however, their functions during DENV infection are unclear. A previous study showed that the canonical OST activity was dispensable for DENV replication, suggesting that the OST complexes serve as scaffolds for DENV replication. However, our work demonstrates that one function of the OST complex during DENV infection is to provide oxidoreductase activity via the OST subunit MAGT1. We also show that MAGT1 associates with DENV NS1 and NS4B during viral infection, suggesting that these nonstructural proteins may be targets of MAGT1 oxidoreductase activity. These results provide insight into the cell biology of DENV infection, which may guide the development of antivirals against DENV.
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Ghosh A, Urquhart J, Daly S, Ferguson A, Scotcher D, Morris AAM, Clayton-Smith J. Phenotypic Heterogeneity in a Congenital Disorder of Glycosylation Caused by Mutations in STT3A. J Child Neurol 2017; 32:560-565. [PMID: 28424003 DOI: 10.1177/0883073817696816] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
STT3A encodes the catalytic subunit of the oligosaccharyltransferase complex. A congenital disorder of glycosylation caused by mutations in STT3A has only been reported in one family to date, associated with a Type I congenital disorder of glycosylation pattern of transferrin glycoforms. The authors describe a further 5 related individuals with a likely pathogenic variant in STT3A, 2 of whom also had variants in TUSC3. Common phenotypic features in all symptomatic individuals include developmental delay, intellectual disability, with absent speech and seizures. Two individuals also developed episodic hypothermia and altered consciousness. The family were investigated by autozygosity mapping, which revealed both a homozygous region containing STT3A and, in addition, a homozygous deletion of TUSC3 in one child. A likely pathogenic variant in STT3A was confirmed on Sanger sequencing of all affected individuals: the authors discuss the molecular findings in detail and further delineate the clinical phenotype of this rare disorder.
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Affiliation(s)
- Arunabha Ghosh
- 1 Willink Biochemical Genetics Unit, Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.,2 School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Jill Urquhart
- 3 Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Sarah Daly
- 3 Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Anne Ferguson
- 4 Community Paediatrics, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Diana Scotcher
- 3 Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Andrew A M Morris
- 1 Willink Biochemical Genetics Unit, Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Jill Clayton-Smith
- 3 Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.,5 Institute of Evolution, Systems and Genomics, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK
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Cherepanova N, Shrimal S, Gilmore R. N-linked glycosylation and homeostasis of the endoplasmic reticulum. Curr Opin Cell Biol 2016; 41:57-65. [PMID: 27085638 DOI: 10.1016/j.ceb.2016.03.021] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/24/2016] [Accepted: 03/30/2016] [Indexed: 01/17/2023]
Abstract
As a major site of protein biosynthesis, homeostasis of the endoplasmic reticulum is critical for cell viability. Asparagine linked glycosylation of newly synthesized proteins by the oligosaccharyltransferase plays a central role in ER homeostasis due to the use of protein-linked oligosaccharides as recognition and timing markers for glycoprotein quality control pathways that discriminate between correctly folded proteins and terminally malfolded proteins destined for ER associated degradation. Recent findings indicate how the oligosaccharyltransferase achieves efficient and accurate glycosylation of the diverse proteins that enter the endoplasmic reticulum. In metazoan organisms two distinct OST complexes cooperate to maximize the glycosylation of nascent proteins. The STT3B complex glycosylates acceptor sites that have been skipped by the translocation channel associated STT3A complex.
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Affiliation(s)
- Natalia Cherepanova
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, United States
| | - Shiteshu Shrimal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, United States
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, United States.
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Mammalian cells lacking either the cotranslational or posttranslocational oligosaccharyltransferase complex display substrate-dependent defects in asparagine linked glycosylation. Sci Rep 2016; 6:20946. [PMID: 26864433 PMCID: PMC4750078 DOI: 10.1038/srep20946] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/13/2016] [Indexed: 02/01/2023] Open
Abstract
Asparagine linked glycosylation of proteins is an essential protein modification reaction in most eukaryotic organisms. Metazoan organisms express two oligosaccharyltransferase complexes that are composed of a catalytic subunit (STT3A or STT3B) assembled with a shared set of accessory subunits and one to two complex specific subunits. siRNA mediated knockdowns of STT3A and STT3B in HeLa cells have shown that the two OST complexes have partially non-overlapping roles in N-linked glycosylation. However, incomplete siRNA mediated depletion of STT3A or STT3B reduces the impact of OST complex loss, thereby complicating the interpretation of experimental results. Here, we have used the CRISPR/Cas9 gene editing technology to create viable HEK293 derived cells lines that are deficient for a single catalytic subunit (STT3A or STT3B) or two STT3B-specific accessory subunits (MagT1 and TUSC3). Analysis of protein glycosylation in the STT3A, STT3B and MagT1/TUSC3 null cell lines revealed that these cell lines are superior tools for investigating the in vivo role and substrate preferences of the STT3A and STT3B complexes.
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Abstract
INTRODUCTION Glycans are increasingly important in the development of new biopharmaceuticals with optimized efficacy, half-life, and antigenicity. Current expression platforms for recombinant glycoprotein therapeutics typically do not produce homogeneous glycans and frequently display non-human glycans which may cause unwanted side effects. To circumvent these issues, glyco-engineering has been applied to different expression systems including mammalian cells, insect cells, yeast, and plants. AREAS COVERED This review summarizes recent developments in glyco-engineering focusing mainly on in vivo expression systems for recombinant proteins. The highlighted strategies aim at producing glycoproteins with homogeneous N- and O-linked glycans of defined composition. EXPERT OPINION Glyco-engineering of expression platforms is increasingly recognized as an important strategy to improve biopharmaceuticals. A better understanding and control of the factors leading to glycan heterogeneity will allow simplified production of recombinant glycoprotein therapeutics with less variation in terms of glycosylation. Further technological advances will have a major impact on manufacturing processes and may provide a completely new class of glycoprotein therapeutics with customized functions.
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Affiliation(s)
- Martina Dicker
- a 1 University of Natural Resources and Life Sciences , Department of Applied Genetics and Cell Biology , Muthgasse 18, Vienna, Austria
| | - Richard Strasser
- b 2 University of Natural Resources and Life Sciences, Department of Applied Genetics and Cell Biology , Muthgasse 18, Vienna, Austria +43 1 47654 6705 ; +43 1 47654 6392 ;
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