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Wong MY, Chen K, Antonopoulos A, Kasper BT, Dewal MB, Taylor RJ, Whittaker CA, Hein PP, Dell A, Genereux JC, Haslam SM, Mahal LK, Shoulders MD. XBP1s activation can globally remodel N-glycan structure distribution patterns. Proc Natl Acad Sci U S A 2018; 115:E10089-E10098. [PMID: 30305426 PMCID: PMC6205500 DOI: 10.1073/pnas.1805425115] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Classically, the unfolded protein response (UPR) safeguards secretory pathway proteostasis. The most ancient arm of the UPR, the IRE1-activated spliced X-box binding protein 1 (XBP1s)-mediated response, has roles in secretory pathway maturation beyond resolving proteostatic stress. Understanding the consequences of XBP1s activation for cellular processes is critical for elucidating mechanistic connections between XBP1s and development, immunity, and disease. Here, we show that a key functional output of XBP1s activation is a cell type-dependent shift in the distribution of N-glycan structures on endogenous membrane and secreted proteomes. For example, XBP1s activity decreased levels of sialylation and bisecting GlcNAc in the HEK293 membrane proteome and secretome, while substantially increasing the population of oligomannose N-glycans only in the secretome. In HeLa cell membranes, stress-independent XBP1s activation increased the population of high-mannose and tetraantennary N-glycans, and also enhanced core fucosylation. mRNA profiling experiments suggest that XBP1s-mediated remodeling of the N-glycome is, at least in part, a consequence of coordinated transcriptional resculpting of N-glycan maturation pathways by XBP1s. The discovery of XBP1s-induced N-glycan structural remodeling on a glycome-wide scale suggests that XBP1s can act as a master regulator of N-glycan maturation. Moreover, because the sugars on cell-surface proteins or on proteins secreted from an XBP1s-activated cell can be molecularly distinct from those of an unactivated cell, these findings reveal a potential new mechanism for translating intracellular stress signaling into altered interactions with the extracellular environment.
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Affiliation(s)
- Madeline Y Wong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Kenny Chen
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | | | - Brian T Kasper
- Biomedical Chemistry Institute, Department of Chemistry, New York University, New York, NY 10003
| | - Mahender B Dewal
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Rebecca J Taylor
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Charles A Whittaker
- Barbara K. Ostrom (1978) Bioinformatics and Computing Facility, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Pyae P Hein
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Anne Dell
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Joseph C Genereux
- Department of Chemistry, University of California, Riverside, CA 92521
| | - Stuart M Haslam
- Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom;
| | - Lara K Mahal
- Biomedical Chemistry Institute, Department of Chemistry, New York University, New York, NY 10003;
| | - Matthew D Shoulders
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139;
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Global N-linked Glycosylation is Not Significantly Impaired in Myoblasts in Congenital Myasthenic Syndromes Caused by Defective Glutamine-Fructose-6-Phosphate Transaminase 1 (GFPT1). Biomolecules 2015; 5:2758-81. [PMID: 26501342 PMCID: PMC4693256 DOI: 10.3390/biom5042758] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/28/2015] [Accepted: 10/13/2015] [Indexed: 12/11/2022] Open
Abstract
Glutamine-fructose-6-phosphate transaminase 1 (GFPT1) is the first enzyme of the hexosamine biosynthetic pathway. It transfers an amino group from glutamine to fructose-6-phosphate to yield glucosamine-6-phosphate, thus providing the precursor for uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) synthesis. UDP-GlcNAc is an essential substrate for all mammalian glycosylation biosynthetic pathways and N-glycan branching is especially sensitive to alterations in the concentration of this sugar nucleotide. It has been reported that GFPT1 mutations lead to a distinct sub-class of congenital myasthenic syndromes (CMS) termed “limb-girdle CMS with tubular aggregates”. CMS are hereditary neuromuscular transmission disorders in which neuromuscular junctions are impaired. To investigate whether alterations in protein glycosylation at the neuromuscular junction might be involved in this impairment, we have employed mass spectrometric strategies to study the N-glycomes of myoblasts and myotubes derived from two healthy controls, three GFPT1 patients, and four patients with other muscular diseases, namely CMS caused by mutations in DOK7, myopathy caused by mutations in MTND5, limb girdle muscular dystrophy type 2A (LGMD2A), and Pompe disease. A comparison of the relative abundances of bi-, tri-, and tetra-antennary N-glycans in each of the cell preparations revealed that all samples exhibited broadly similar levels of branching. Moreover, although some differences were observed in the relative abundances of some of the N-glycan constituents, these variations were modest and were not confined to the GFPT1 samples. Therefore, GFPT1 mutations in CMS patients do not appear to compromise global N-glycosylation in muscle cells.
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for the period 2005-2006. MASS SPECTROMETRY REVIEWS 2011; 30:1-100. [PMID: 20222147 DOI: 10.1002/mas.20265] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This review is the fourth update of the original review, published in 1999, on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2006. The review covers fundamental studies, fragmentation of carbohydrate ions, method developments, and applications of the technique to the analysis of different types of carbohydrate. Specific compound classes that are covered include carbohydrate polymers from plants, N- and O-linked glycans from glycoproteins, glycated proteins, glycolipids from bacteria, glycosides, and various other natural products. There is a short section on the use of MALDI-TOF mass spectrometry for the study of enzymes involved in glycan processing, a section on industrial processes, particularly the development of biopharmaceuticals and a section on the use of MALDI-MS to monitor products of chemical synthesis of carbohydrates. Large carbohydrate-protein complexes and glycodendrimers are highlighted in this final section.
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Affiliation(s)
- David J Harvey
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford OX1 3QU, UK.
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Haslam SM, Julien S, Burchell JM, Monk CR, Ceroni A, Garden OA, Dell A. Characterizing the glycome of the mammalian immune system. Immunol Cell Biol 2008; 86:564-73. [PMID: 18725885 DOI: 10.1038/icb.2008.54] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The outermost layer of all immune cells, the glycocalyx, is composed of a complex mixture of glycoproteins, glycolipids and lectins, which specifically recognize particular glycan epitopes. As the glycocalyx is the cell's primary interface with the external environment many biologically significant events can be attributed to glycan recognition. For this reason the rapidly expanding glycomics field is being increasingly recognized as an important component in our quest to better understand the functioning of the immune system. In this review, we highlight the current status of immune cell glycomics, with particular attention being paid to T- and B-lymphocytes and dendritic cells. We also describe the strategies and methodologies used to define immune cell glycomes.
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Affiliation(s)
- Stuart M Haslam
- Division of Molecular Biosciences, Imperial College London, and Breast Cancer Biology Group, Guy's Hospital, London, UK
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