1
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Skurska E, Szulc B, Kreczko K, Olczak M. Mutations in the SLC35C1 gene, contributing to significant differences in fucosylation patterns, may underlie the diverse phenotypic manifestations observed in leukocyte adhesion deficiency type II patients. Int J Biochem Cell Biol 2024; 173:106602. [PMID: 38843991 DOI: 10.1016/j.biocel.2024.106602] [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: 02/22/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/10/2024]
Abstract
Congenital disorders of glycosylation (CDG) are a large family of genetic diseases resulting from defects in the synthesis of glycans and the attachment of glycans to macromolecules. The CDG known as leukocyte adhesion deficiency II (LAD II) is an autosomal, recessive disorder caused by mutations in the SLC35C1 gene, encoding a transmembrane protein of the Golgi apparatus, involved in GDP-fucose transport from the cytosol to the Golgi lumen. In this study, a cell-based model was used as a tool to characterize the molecular background of a therapy based on a fucose-supplemented diet. Such therapies have been successfully introduced in some (but not all) known cases of LAD II. In this study, the effect of external fucose was analyzed in SLC35C1 KO cell lines, expressing 11 mutated SLC35C1 proteins, previously discovered in patients with an LAD II diagnosis. For many of them, the cis-Golgi subcellular localization was affected; however, some proteins were localized properly. Additionally, although mutated SLC35C1 caused different α-1-6 core fucosylation of N-glycans, which explains previously described, more or less severe disorder symptoms, the differences practically disappeared after external fucose supplementation, with fucosylation restored to the level observed in healthy cells. This indicates that additional fucose in the diet should improve the condition of all patients. Thus, for patients diagnosed with LAD II we advocate careful analysis of particular mutations using the SLC35C1-KO cell line-based model, to predict changes in localization and fucosylation rate. We also recommend searching for additional mutations in the human genome of LAD II patients, when fucose supplementation does not influence patients' state.
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Affiliation(s)
- E Skurska
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - B Szulc
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - K Kreczko
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
| | - M Olczak
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland.
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2
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Wilson LFL, Dendooven T, Hardwick SW, Echevarría-Poza A, Tryfona T, Krogh KBRM, Chirgadze DY, Luisi BF, Logan DT, Mani K, Dupree P. The structure of EXTL3 helps to explain the different roles of bi-domain exostosins in heparan sulfate synthesis. Nat Commun 2022; 13:3314. [PMID: 35676258 PMCID: PMC9178029 DOI: 10.1038/s41467-022-31048-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/31/2022] [Indexed: 11/08/2022] Open
Abstract
Heparan sulfate is a highly modified O-linked glycan that performs diverse physiological roles in animal tissues. Though quickly modified, it is initially synthesised as a polysaccharide of alternating β-D-glucuronosyl and N-acetyl-α-D-glucosaminyl residues by exostosins. These enzymes generally possess two glycosyltransferase domains (GT47 and GT64)-each thought to add one type of monosaccharide unit to the backbone. Although previous structures of murine exostosin-like 2 (EXTL2) provide insight into the GT64 domain, the rest of the bi-domain architecture is yet to be characterised; hence, how the two domains co-operate is unknown. Here, we report the structure of human exostosin-like 3 (EXTL3) in apo and UDP-bound forms. We explain the ineffectiveness of EXTL3's GT47 domain to transfer β-D-glucuronosyl units, and we observe that, in general, the bi-domain architecture would preclude a processive mechanism of backbone extension. We therefore propose that heparan sulfate backbone polymerisation occurs by a simple dissociative mechanism.
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Affiliation(s)
- L F L Wilson
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, 22903, USA
| | - T Dendooven
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - S W Hardwick
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - A Echevarría-Poza
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - T Tryfona
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - K B R M Krogh
- Department of Protein Biochemistry and Stability, Novozymes A/S, Krogshøjvej 36, 2880, Bagsværd, Denmark
| | - D Y Chirgadze
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - B F Luisi
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - D T Logan
- Biochemistry and Structural Biology, Centre for Molecular Protein Science, Department of Chemistry, Lund University, SE-221 00, Lund, Sweden
| | - K Mani
- Department of Experimental Medical Science, Division of Neuroscience, Glycobiology Group, Lund University, SE-221 00, Lund, Sweden.
| | - P Dupree
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK.
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3
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Aw R, De Wachter C, Laukens B, De Rycke R, De Bruyne M, Bell D, Callewaert N, Polizzi KM. Knockout of RSN1, TVP18 or CSC1-2 causes perturbation of Golgi cisternae in Pichia pastoris. Traffic 2020; 22:48-63. [PMID: 33263222 DOI: 10.1111/tra.12773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 11/29/2022]
Abstract
The structural organization of the Golgi stacks in mammalian cells is intrinsically linked to function, including glycosylation, but the role of morphology is less clear in lower eukaryotes. Here we investigated the link between the structural organization of the Golgi and secretory pathway function using Pichia pastoris as a model system. To unstack the Golgi cisternae, we disrupted 18 genes encoding proteins in the secretory pathway without loss of viability. Using biosensors, confocal microscopy and transmission electron microscopy we identified three strains with irreversible perturbations in the stacking of the Golgi cisternae, all of which had disruption in genes that encode proteins with annotated function as or homology to calcium/calcium permeable ion channels. Despite this, no variation in the secretory pathway for ER size, whole cell glycomics or recombinant protein glycans was observed. Our investigations showed the robust nature of the secretory pathway in P. pastoris and suggest that Ca2+ concentration, homeostasis or signalling may play a significant role for Golgi stacking in this organism and should be investigated in other organisms.
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Affiliation(s)
- Rochelle Aw
- Department of Chemical Engineering, Imperial College London, London, UK.,Imperial College Centre for Synthetic Biology, Imperial College London, London, United Kingdom
| | - Charlot De Wachter
- VIB-UGent, Center for Medical Biotechnology, Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Bram Laukens
- VIB-UGent, Center for Medical Biotechnology, Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Riet De Rycke
- Department of Biomedical Molecular Biology and Expertise Centre for Transmission Electron Microscopy, Ghent University, Ghent, Belgium.,VIB Center for Inflammation Research and BioImaging Core, Ghent, Belgium
| | - Michiel De Bruyne
- Department of Biomedical Molecular Biology and Expertise Centre for Transmission Electron Microscopy, Ghent University, Ghent, Belgium.,VIB Center for Inflammation Research and BioImaging Core, Ghent, Belgium
| | - David Bell
- Section for Structural Biology, Department of Medicine, Imperial College London, London, United Kingdom.,London Biofoundry, Imperial College London, London, United Kingdom
| | - Nico Callewaert
- VIB-UGent, Center for Medical Biotechnology, Ghent, Belgium.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Karen M Polizzi
- Department of Chemical Engineering, Imperial College London, London, UK.,Imperial College Centre for Synthetic Biology, Imperial College London, London, United Kingdom
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4
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Anderson CT, Kieber JJ. Dynamic Construction, Perception, and Remodeling of Plant Cell Walls. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:39-69. [PMID: 32084323 DOI: 10.1146/annurev-arplant-081519-035846] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Plant cell walls are dynamic structures that are synthesized by plants to provide durable coverings for the delicate cells they encase. They are made of polysaccharides, proteins, and other biomolecules and have evolved to withstand large amounts of physical force and to resist external attack by herbivores and pathogens but can in many cases expand, contract, and undergo controlled degradation and reconstruction to facilitate developmental transitions and regulate plant physiology and reproduction. Recent advances in genetics, microscopy, biochemistry, structural biology, and physical characterization methods have revealed a diverse set of mechanisms by which plant cells dynamically monitor and regulate the composition and architecture of their cell walls, but much remains to be discovered about how the nanoscale assembly of these remarkable structures underpins the majestic forms and vital ecological functions achieved by plants.
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Affiliation(s)
- Charles T Anderson
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA;
| | - Joseph J Kieber
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA;
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5
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Stewart TJ, Takahashi K, Whitaker RH, Raska M, Placzek WJ, Novak J, Renfrow MB. IgA1 hinge-region clustered glycan fidelity is established early during semi-ordered glycosylation by GalNAc-T2. Glycobiology 2019; 29:543-556. [PMID: 30759204 PMCID: PMC6583770 DOI: 10.1093/glycob/cwz007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 01/13/2019] [Accepted: 02/04/2019] [Indexed: 01/03/2023] Open
Abstract
GalNAc-type O-glycans are often added to proteins post-translationally in a clustered manner in repeat regions of proteins, such as mucins and IgA1. Observed IgA1 glycosylation patterns show that glycans occur at similar sites with similar structures. It is not clear how the sites and number of glycans added to IgA1, or other proteins, can follow a conservative process. GalNAc-transferases initiate GalNAc-type glycosylation. In IgA nephropathy, an autoimmune disease, the sites and O-glycan structures of IgA1 hinge-region are altered, giving rise to a glycan autoantigen. To better understand how GalNAc-transferases determine sites and densities of clustered O-glycans, we used IgA1 hinge-region (HR) segment as a probe. Using LC-MS, we demonstrated a semi-ordered process of glycosylation by GalNAc-T2 towards the IgA1 HR. The catalytic domain was responsible for selection of four initial sites based on amino-acid sequence recognition. Both catalytic and lectin domains were involved in multiple second site-selections, each dependent on initial site-selection. Our data demonstrated that multiple start-sites and follow-up pathways were key to increasing the number of glycans added. The lectin domain predominately enhanced IgA1 HR glycan density by increasing synthesis pathway exploration by GalNAc-T2. Our data indicated a link between site-specific glycan addition and clustered glycan density that defines a mechanism of how conserved clustered O-glycosylation patterns and glycoform populations of IgA1 can be controlled by GalNAc-T2. Together, these findings characterized a correlation between glycosylation pathway diversity and glycosylation density, revealing mechanisms by which a single GalNAc-T isozyme can limit and define glycan heterogeneity in a disease-relevant context.
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Affiliation(s)
- Tyler J Stewart
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kazuo Takahashi
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Nephrology, Fujita Health University, Toyoake, Japan
| | - Robert H Whitaker
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Milan Raska
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Immunology, Palacky University and University Hospital, Olomouc, Czech Republic
| | - William J Placzek
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Matthew B Renfrow
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
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6
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Khoder-Agha F, Sosicka P, Escriva Conde M, Hassinen A, Glumoff T, Olczak M, Kellokumpu S. N-acetylglucosaminyltransferases and nucleotide sugar transporters form multi-enzyme-multi-transporter assemblies in golgi membranes in vivo. Cell Mol Life Sci 2019; 76:1821-1832. [PMID: 30737517 PMCID: PMC6453868 DOI: 10.1007/s00018-019-03032-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/07/2019] [Accepted: 01/28/2019] [Indexed: 01/05/2023]
Abstract
Branching and processing of N-glycans in the medial-Golgi rely both on the transport of the donor UDP-N-acetylglucosamine (UDP-GlcNAc) to the Golgi lumen by the SLC35A3 nucleotide sugar transporter (NST) as well as on the addition of the GlcNAc residue to terminal mannoses in nascent N-glycans by several linkage-specific N-acetyl-glucosaminyltransferases (MGAT1-MGAT5). Previous data indicate that the MGATs and NSTs both form higher order assemblies in the Golgi membranes. Here, we investigate their specific and mutual interactions using high-throughput FRET- and BiFC-based interaction screens. We show that MGAT1, MGAT2, MGAT3, MGAT4B (but not MGAT5) and Golgi alpha-mannosidase IIX (MAN2A2) form several distinct molecular assemblies with each other and that the MAN2A2 acts as a central hub for the interactions. Similar assemblies were also detected between the NSTs SLC35A2, SLC35A3, and SLC35A4. Using in vivo BiFC-based FRET interaction screens, we also identified novel ternary complexes between the MGATs themselves or between the MGATs and the NSTs. These findings suggest that the MGATs and the NSTs self-assemble into multi-enzyme/multi-transporter complexes in the Golgi membranes in vivo to facilitate efficient synthesis of complex N-glycans.
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Affiliation(s)
- Fawzi Khoder-Agha
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7A, 90220, Oulu, Finland
| | - Paulina Sosicka
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Wrocław, Poland
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Maria Escriva Conde
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7A, 90220, Oulu, Finland
- Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Antti Hassinen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7A, 90220, Oulu, Finland
- Institute of Molecular Medicine, Helsinki, Finland
| | - Tuomo Glumoff
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7A, 90220, Oulu, Finland
| | - Mariusz Olczak
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Wrocław, Poland
| | - Sakari Kellokumpu
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7A, 90220, Oulu, Finland.
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7
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Groux-Degroote S, Schulz C, Cogez V, Noël M, Portier L, Vicogne D, Solorzano C, Dall'Olio F, Steenackers A, Mortuaire M, Gonzalez-Pisfil M, Henry M, Foulquier F, Héliot L, Harduin-Lepers A. The extended cytoplasmic tail of the human B4GALNT2 is critical for its Golgi targeting and post-Golgi sorting. FEBS J 2018; 285:3442-3463. [PMID: 30067891 DOI: 10.1111/febs.14621] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/15/2018] [Accepted: 07/31/2018] [Indexed: 11/25/2022]
Abstract
The Sda /Cad antigen reported on glycoconjugates of human tissues has an increasingly recognized wide impact on the physio-pathology of different biological systems. The last step of its biosynthesis relies on the enzymatic activity of the β1,4-N-acetylgalactosaminyltransferase-II (B4GALNT2), which shows the highest expression level in healthy colon. Previous studies reported the occurrence in human colonic cells of two B4GALNT2 protein isoforms that differ in the length of their cytoplasmic tail, the long isoform showing an extended 66-amino acid tail. We examined here, the subcellular distribution of the two B4GALNT2 protein isoforms in stably transfected colonic LS174T cells and in transiently transfected HeLa cells using fluorescence microscopy. While a similar subcellular distribution at the trans-Golgi cisternae level was observed for the two isoforms, our study pointed to an atypical subcellular localization of the long B4GALNT2 isoform into dynamic vesicles. We demonstrated a critical role of its extended cytoplasmic tail for its Golgi targeting and post-Golgi sorting and highlighted the existence of a newly described post-Golgi sorting signal as well as a previously undescribed fate of a Golgi glycosyltransferase. DATABASE The proteins β1,4GalNAcT II, β1,4-GalT1, FucT I, FucT VI and ST3Gal IV are noted B4GALNT2, B4GALT1, FUT1, FUT6 and ST3GAL4, whereas the corresponding human genes are noted B4GALNT2, B4GALT1, FUT1, FUT6 and ST3GAL4 according to the HUGO nomenclature.
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Affiliation(s)
- Sophie Groux-Degroote
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Céline Schulz
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France.,Univ. Lille, CNRS, UMR 8523 - PhLAM - Laboratoire de Physique des Lasers, Atomes, Molécules, Lille, France
| | - Virginie Cogez
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Maxence Noël
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Lucie Portier
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Dorothée Vicogne
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Carlos Solorzano
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Fabio Dall'Olio
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, Italy
| | - Agata Steenackers
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Marlène Mortuaire
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Mariano Gonzalez-Pisfil
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Laboratoire de Physique des Lasers, Atomes, Molécules, Lille, France
| | - Mélanie Henry
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Laboratoire de Physique des Lasers, Atomes, Molécules, Lille, France
| | - François Foulquier
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Laurent Héliot
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Laboratoire de Physique des Lasers, Atomes, Molécules, Lille, France
| | - Anne Harduin-Lepers
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
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8
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van de Meene AML, Doblin MS, Bacic A. The plant secretory pathway seen through the lens of the cell wall. PROTOPLASMA 2017; 254:75-94. [PMID: 26993347 DOI: 10.1007/s00709-016-0952-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 01/27/2016] [Accepted: 02/01/2016] [Indexed: 05/18/2023]
Abstract
Secretion in plant cells is often studied by looking at well-characterised, evolutionarily conserved membrane proteins associated with particular endomembrane compartments. Studies using live cell microscopy and fluorescent proteins have illuminated the highly dynamic nature of trafficking, and electron microscopy studies have resolved the ultrastructure of many compartments. Biochemical and molecular analyses have further informed about the function of particular proteins and endomembrane compartments. In plants, there are over 40 cell types, each with highly specialised functions, and hence potential variations in cell biological processes and cell wall structure. As the primary function of secretion in plant cells is for the biosynthesis of cell wall polysaccharides and apoplastic transport complexes, it follows that utilising our knowledge of cell wall glycosyltransferases (GTs) and their polysaccharide products will inform us about secretion. Indeed, this knowledge has led to novel insights into the secretory pathway, including previously unseen post-TGN secretory compartments. Conversely, our knowledge of trafficking routes of secretion will inform us about polarised and localised deposition of cell walls and their constituent polysaccharides/glycoproteins. In this review, we look at what is known about cell wall biosynthesis and the secretory pathway and how the different approaches can be used in a complementary manner to study secretion and provide novel insights into these processes.
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Affiliation(s)
- A M L van de Meene
- ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - M S Doblin
- ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Antony Bacic
- ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, Victoria, 3010, Australia.
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9
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Lorenz V, Ditamo Y, Cejas RB, Carrizo ME, Bennett EP, Clausen H, Nores GA, Irazoqui FJ. Extrinsic Functions of Lectin Domains in O-N-Acetylgalactosamine Glycan Biosynthesis. J Biol Chem 2016; 291:25339-25350. [PMID: 27738109 PMCID: PMC5207237 DOI: 10.1074/jbc.m116.740795] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/30/2016] [Indexed: 01/06/2023] Open
Abstract
Glycan biosynthesis occurs mainly in Golgi. Molecular organization and functional regulation of this process are not well understood. We evaluated the extrinsic effect of lectin domains (β-trefoil fold) of polypeptide GalNAc-transferases (ppGalNAc-Ts) on catalytic activity of glycosyltransferases during O-GalNAc glycan biosynthesis. The presence of lectin domain T3lec or T4lec during ppGalNAc-T2 and ppGalNAc-T3 catalytic reaction had a clear inhibitory effect on GalNAc-T activity. Interaction of T3lec or T4lec with ppGalNAc-T2 catalytic domain was not mediated by carbohydrate. T3lec, but not T2lec and T4lec, had a clear activating effect on Drosophila melanogaster core 1 galactosyltransferase enzyme activity and a predominant inhibitory effect on in vivo human core 1 glycan biosynthesis. The regulatory role of the β-trefoil fold of ppGalNAc-Ts in enzymatic activity of glycosyltransferases involved in the O-glycan biosynthesis pathway, described here for the first time, helps clarify the mechanism of biosynthesis of complex biopolymers (such as glycans) that is not template-driven.
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Affiliation(s)
- Virginia Lorenz
- From the Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina and
| | - Yanina Ditamo
- From the Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina and
| | - Romina B Cejas
- From the Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina and
| | - Maria E Carrizo
- From the Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina and
| | - Eric P Bennett
- Copenhagen Center for Glycomics, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Henrik Clausen
- Copenhagen Center for Glycomics, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Gustavo A Nores
- From the Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina and
| | - Fernando J Irazoqui
- From the Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina and
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10
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Vildanova MS, Wang W, Smirnova EA. Specific organization of Golgi apparatus in plant cells. BIOCHEMISTRY (MOSCOW) 2014; 79:894-906. [DOI: 10.1134/s0006297914090065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Lu H, Wang SS, Wang WL, Zhang L, Zhao BY. Effect of swainsonine in Oxytropis kansuensis on Golgi α-mannosidase II expression in the brain tissues of Sprague-Dawley rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:7407-7412. [PMID: 24741992 DOI: 10.1021/jf501299d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The purpose of this study was to observe the effects of swainsonine in Oxytropis kansuensis on the expression of Golgi α-mannosidase II (MAN2A1) in the brain tissues of Sprague-Dawley (SD) rats. Twenty-four SD rats were randomly divided into four groups (experimental groups I, II, and III and a control group) of six animals each. The rats were penned as groups and fed feeds containing either 15% (swainsonine content = 0.003%), 30% (swainsonine content = 0.006%), or 45% (swainsonine content = 0.009%) O. kansuensis for experimental groups I-III, respectively, or complete feed for the control group. One hundred and nineteen days after poisoning, all rats showed neurological disorders at different degrees, which were considered to be successful establishment of a chronic poisoning model of O. kansuensis. Rats were sacrificed, and MAN2A1 expression of brain tissues was detected by immunohistochemistry and RT-PCR. The results showed that MAN2A1 was either not expressed or lowly expressed in the molecular layer of the cerebral cortex and hippocampal layers, but was found to be highly expressed in other areas of the brain. MAN2A1 expression decreased in the cerebrum and cerebellum in experimental groups when compared to the control group, whereas the expression of MAN2A1 mRNA was inhibited in cerebral and cerebellar tissues by O. kansuensis. These results indicated that O. kansuensis treatment could reduce the expression of MAN2A1 in brain tissues of SD rats.
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Affiliation(s)
- Hao Lu
- College of Veterinary Medicine, Northwest A&F University , Yangling, Shaanxi 712100, China
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12
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Dilokpimol A, Poulsen CP, Vereb G, Kaneko S, Schulz A, Geshi N. Galactosyltransferases from Arabidopsis thaliana in the biosynthesis of type II arabinogalactan: molecular interaction enhances enzyme activity. BMC PLANT BIOLOGY 2014; 14:90. [PMID: 24693939 PMCID: PMC4234293 DOI: 10.1186/1471-2229-14-90] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 03/25/2014] [Indexed: 05/18/2023]
Abstract
BACKGROUND Arabinogalactan proteins are abundant proteoglycans present on cell surfaces of plants and involved in many cellular processes, including somatic embryogenesis, cell-cell communication and cell elongation. Arabinogalactan proteins consist mainly of glycan, which is synthesized by post-translational modification of proteins in the secretory pathway. Importance of the variations in the glycan moiety of arabinogalactan proteins for their functions has been implicated, but its biosynthetic process is poorly understood. RESULTS We have identified a novel enzyme in the biosynthesis of the glycan moiety of arabinogalactan proteins. The At1g08280 (AtGALT29A) from Arabidopsis thaliana encodes a putative glycosyltransferase (GT), which belongs to the Carbohydrate Active Enzyme family GT29. AtGALT29A co-expresses with other arabinogalactan GTs, AtGALT31A and AtGLCAT14A. The recombinant AtGALT29A expressed in Nicotiana benthamiana demonstrated a galactosyltransferase activity, transferring galactose from UDP-galactose to a mixture of various oligosaccharides derived from arabinogalactan proteins. The galactose-incorporated products were analyzed using structure-specific hydrolases indicating that the recombinant AtGALT29A possesses β-1,6-galactosyltransferase activity, elongating β-1,6-galactan side chains and forming 6-Gal branches on the β-1,3-galactan main chain of arabinogalactan proteins. The fluorescence tagged AtGALT29A expressed in N. benthamiana was localized to Golgi stacks where it interacted with AtGALT31A as indicated by Förster resonance energy transfer. Biochemically, the enzyme complex containing AtGALT31A and AtGALT29A could be co-immunoprecipitated and the isolated protein complex exhibited increased level of β-1,6-galactosyltransferase activities compared to AtGALT29A alone. CONCLUSIONS AtGALT29A is a β-1,6-galactosyltransferase and can interact with AtGALT31A. The complex can work cooperatively to enhance the activities of adding galactose residues 6-linked to β-1,6-galactan and to β-1,3-galactan. The results provide new knowledge of the glycosylation process of arabinogalactan proteins and the functional significance of protein-protein interactions among O-glycosylation enzymes.
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Affiliation(s)
- Adiphol Dilokpimol
- Department of Plant and Environmental Sciences, Thorvaldsensvej 40, 1871 Frederiksberg, C, Denmark
- Present address: Fungal Physiology, CBS-KNAW, Fungal Biodiversity Center, Uppsalalaan 8, Utrecht 3584, CT, The Netherlands
| | - Christian Peter Poulsen
- Department of Plant and Environmental Sciences, Thorvaldsensvej 40, 1871 Frederiksberg, C, Denmark
| | - György Vereb
- Department of Biophysics and Cell Biology, and MTA-DE Cell Biology and Signaling Research Group, University of Debrecen, Debrecen, Hungary
| | - Satoshi Kaneko
- Food Biotechnology Division, National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan
| | - Alexander Schulz
- Department of Plant and Environmental Sciences, Thorvaldsensvej 40, 1871 Frederiksberg, C, Denmark
| | - Naomi Geshi
- Department of Plant and Environmental Sciences, Thorvaldsensvej 40, 1871 Frederiksberg, C, Denmark
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13
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Brooks SA. Protein glycosylation in diverse cell systems: implications for modification and analysis of recombinant proteins. Expert Rev Proteomics 2014; 3:345-59. [PMID: 16771706 DOI: 10.1586/14789450.3.3.345] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A major challenge for the biotechnology industry is to engineer the glycosylation pathways of expression systems to synthesize recombinant proteins with human glycosylation. Inappropriate glycosylation can result in reduced activity, limited half-life in circulation and unwanted immunogenicity. In this review, the complexities of glycosylation in human cells are explained and compared with glycosylation in bacteria, yeasts, fungi, insects, plants and nonhuman mammalian species. Key advances in the engineering of the glycosylation of expression systems are highlighted. Advances in the challenging and technically complex field of glycan analysis are also described. The emergence of a new generation of expression systems with sophisticated engineering for humanized glycosylation of glycoproteins appears to be on the horizon.
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Affiliation(s)
- Susan A Brooks
- Oxford Brookes University, School of Biological & Molecular Sciences, Gipsy Lane, Headington, Oxford, OX3 0BP, UK.
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14
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The influence of Aspergillus niger transcription factors AraR and XlnR in the gene expression during growth in D-xylose, L-arabinose and steam-exploded sugarcane bagasse. Fungal Genet Biol 2013; 60:29-45. [PMID: 23892063 DOI: 10.1016/j.fgb.2013.07.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 07/03/2013] [Accepted: 07/17/2013] [Indexed: 12/29/2022]
Abstract
The interest in the conversion of plant biomass to renewable fuels such as bioethanol has led to an increased investigation into the processes regulating biomass saccharification. The filamentous fungus Aspergillus niger is an important microorganism capable of producing a wide variety of plant biomass degrading enzymes. In A. niger the transcriptional activator XlnR and its close homolog, AraR, controls the main (hemi-)cellulolytic system responsible for plant polysaccharide degradation. Sugarcane is used worldwide as a feedstock for sugar and ethanol production, while the lignocellulosic residual bagasse can be used in different industrial applications, including ethanol production. The use of pentose sugars from hemicelluloses represents an opportunity to further increase production efficiencies. In the present study, we describe a global gene expression analysis of A. niger XlnR- and AraR-deficient mutant strains, grown on a D-xylose/L-arabinose monosaccharide mixture and steam-exploded sugarcane bagasse. Different gene sets of CAZy enzymes and sugar transporters were shown to be individually or dually regulated by XlnR and AraR, with XlnR appearing to be the major regulator on complex polysaccharides. Our study contributes to understanding of the complex regulatory mechanisms responsible for plant polysaccharide-degrading gene expression, and opens new possibilities for the engineering of fungi able to produce more efficient enzymatic cocktails to be used in biofuel production.
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15
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Schoberer J, Liebminger E, Botchway SW, Strasser R, Hawes C. Time-resolved fluorescence imaging reveals differential interactions of N-glycan processing enzymes across the Golgi stack in planta. PLANT PHYSIOLOGY 2013; 161:1737-54. [PMID: 23400704 PMCID: PMC3613452 DOI: 10.1104/pp.112.210757] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 02/10/2013] [Indexed: 05/18/2023]
Abstract
N-Glycan processing is one of the most important cellular protein modifications in plants and as such is essential for plant development and defense mechanisms. The accuracy of Golgi-located processing steps is governed by the strict intra-Golgi localization of sequentially acting glycosidases and glycosyltransferases. Their differential distribution goes hand in hand with the compartmentalization of the Golgi stack into cis-, medial-, and trans-cisternae, which separate early from late processing steps. The mechanisms that direct differential enzyme concentration are still unknown, but the formation of multienzyme complexes is considered a feasible Golgi protein localization strategy. In this study, we used two-photon excitation-Förster resonance energy transfer-fluorescence lifetime imaging microscopy to determine the interaction of N-glycan processing enzymes with differential intra-Golgi locations. Following the coexpression of fluorescent protein-tagged amino-terminal Golgi-targeting sequences (cytoplasmic-transmembrane-stem [CTS] region) of enzyme pairs in leaves of tobacco (Nicotiana spp.), we observed that all tested cis- and medial-Golgi enzymes, namely Arabidopsis (Arabidopsis thaliana) Golgi α-mannosidase I, Nicotiana tabacum β1,2-N-acetylglucosaminyltransferase I, Arabidopsis Golgi α-mannosidase II (GMII), and Arabidopsis β1,2-xylosyltransferase, form homodimers and heterodimers, whereas among the late-acting enzymes Arabidopsis β1,3-galactosyltransferase1 (GALT1), Arabidopsis α1,4-fucosyltransferase, and Rattus norvegicus α2,6-sialyltransferase (a nonplant Golgi marker), only GALT1 and medial-Golgi GMII were found to form a heterodimer. Furthermore, the efficiency of energy transfer indicating the formation of interactions decreased considerably in a cis-to-trans fashion. The comparative fluorescence lifetime imaging of several full-length cis- and medial-Golgi enzymes and their respective catalytic domain-deleted CTS clones further suggested that the formation of protein-protein interactions can occur through their amino-terminal CTS region.
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Affiliation(s)
| | - Eva Liebminger
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria (J.S., E.L., R.S.)
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom (J.S., C.H.); and
- Research Complex at Harwell, Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell-Oxford, Didcot OX11 0QX, United Kingdom (S.W.B.)
| | - Stanley W. Botchway
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria (J.S., E.L., R.S.)
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom (J.S., C.H.); and
- Research Complex at Harwell, Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell-Oxford, Didcot OX11 0QX, United Kingdom (S.W.B.)
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria (J.S., E.L., R.S.)
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom (J.S., C.H.); and
- Research Complex at Harwell, Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell-Oxford, Didcot OX11 0QX, United Kingdom (S.W.B.)
| | - Chris Hawes
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria (J.S., E.L., R.S.)
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom (J.S., C.H.); and
- Research Complex at Harwell, Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell-Oxford, Didcot OX11 0QX, United Kingdom (S.W.B.)
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16
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Barrow H, Tam B, Duckworth CA, Rhodes JM, Yu LG. Suppression of core 1 Gal-transferase is associated with reduction of TF and reciprocal increase of Tn, sialyl-Tn and Core 3 glycans in human colon cancer cells. PLoS One 2013; 8:e59792. [PMID: 23536887 PMCID: PMC3607565 DOI: 10.1371/journal.pone.0059792] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 02/18/2013] [Indexed: 12/12/2022] Open
Abstract
It has long been presumed, though with surprisingly little evidence, a competition between Core 1 Gal-transferase (C1GalT), Core 3 GlcNAc-transferase (C3GnT) and sialyl-transferase (ST6GalNAc-T) for elongation of O-linked mucin-type glycans initiated with GalNAcα-Ser/Thr. This study tested this presumption by selective suppression of one of these glycosyltransferases and then analysed the expressions of the enzymatic products of the other three glycosyltransferases. It was found that siRNA suppression of C1GalT markedly reduced the expression of Galβ1,3GalNAcα- (Core 1) and in the meantime increased the expressions of sialyl-GalNAcα- (sialyl-Tn), GalNAcα- (Tn) and GlcNAcβ1,3GalNAcα- (Core 3)-associated glycans in human colon cancer HT29 and SW620 cells. This supports a competitive modification of the GalNAcα-Ser/Thr between C1GalT, C3GnT and ST6GalNAc-T in O-glycan biosynthesis. As Tn, TF and sialyl-Tn are oncofetal antigens and are over-expressed in most human cancers, this information is useful for the development of glycosyltransferase-targeted therapeutic strategies for cancer treatment.
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Affiliation(s)
- Hannah Barrow
- Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Benjamin Tam
- Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Carrie A. Duckworth
- Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Jonathan M. Rhodes
- Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Lu-Gang Yu
- Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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17
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Oikawa A, Lund CH, Sakuragi Y, Scheller HV. Golgi-localized enzyme complexes for plant cell wall biosynthesis. TRENDS IN PLANT SCIENCE 2013; 18:49-58. [PMID: 22925628 DOI: 10.1016/j.tplants.2012.07.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 07/13/2012] [Accepted: 07/18/2012] [Indexed: 05/18/2023]
Abstract
The plant cell wall mostly comprises complex glycans, which are synthesized by numerous enzymes located in the Golgi apparatus and plasma membrane. Protein-protein interactions have been shown to constitute an important organizing principle for glycan biosynthetic enzymes in mammals and yeast. Recent genetic and biochemical data also indicate that such interactions could be common in plant cell wall biosynthesis. In this review, we examine the new findings in protein-protein interactions among plant cell wall biosynthetic enzymes and discuss the possibilities for enzyme complexes in the Golgi apparatus. These new insights in the field may contribute to novel strategies for molecular engineering of the cell wall.
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Affiliation(s)
- Ai Oikawa
- Joint BioEnergy Institute, Feedstocks Division, Emeryville, CA 94608, USA
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18
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Abstract
Most organelles within the exocytic and endocytic pathways typically acidify their interiors, a phenomenon that is known to be crucial for their optimal functioning in eukaryotic cells. This review highlights recent advances in our understanding of how Golgi acidity is maintained and regulated, and how its misregulation contributes to organelle dysfunction and disease. Both its biosynthetic products (glycans) and protein-sorting events are highly sensitive to changes in Golgi luminal pH and are affected in certain human disease states such as cancers and cutis laxa. Other potential disease states that are caused by, or are associated with, Golgi pH misregulation will also be discussed.
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Affiliation(s)
- Antti Rivinoja
- Department of Biochemistry, University of Oulu, Oulu, Finland
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19
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Ferrari ML, Gomez GA, Maccioni HJF. Spatial organization and stoichiometry of N-terminal domain-mediated glycosyltransferase complexes in Golgi membranes determined by fret microscopy. Neurochem Res 2012; 37:1325-34. [PMID: 22388569 DOI: 10.1007/s11064-012-0741-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 01/13/2012] [Accepted: 02/20/2012] [Indexed: 01/25/2023]
Abstract
The functional link between glycolipid glycosyltransferases (GT) relies on the ability of these proteins to form organized molecular complexes. The organization, stoichiometry and composition of these complexes may impact their sorting properties, sub-Golgi localization, and may determine relative efficiency of GT in different glycolipid biosynthetic pathways. In this work, by using Förster resonance energy transfer microscopy in live CHO-K1 cells, we investigated homo- and hetero-complex formation by different GT as well as their spatial organization and molecular stoichiometry on Golgi membranes. We find that GalNAcT and GalT2 Ntd are able to form hetero-complexes in a 1:2 molar ratio at the trans-Golgi network and that GalT2 but not GalNAcT forms homo-complexes. Also, GalNAcT/GalT2 complexes exhibit a stable behavior reflected by its clustered lateral organization. These results reveals that particular topological organization of GTs may have functional implications in determining the composition of glycolipids in cellular membranes.
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Affiliation(s)
- Mariana L Ferrari
- Departamento de Química Biológica, Facultad de Ciencias Químicas, Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC-UNC-CONICET, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
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20
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Gloor Y, Müller-Reichert T, Walch-Solimena C. Co-regulation of the arf-activation cycle and phospholipid-signaling during golgi maturation. Commun Integr Biol 2012; 5:12-5. [PMID: 22482002 DOI: 10.4161/cib.17970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The Golgi apparatus is the central protein sorting station inside eukaryotic cells. Although many regulators of Golgi trafficking have been identified, little is known about their crosstalk. Both the Arf activation cycle and phosphatidylinositol 4-phosphate metabolism have been recognized as key processes in the regulation of vesicular transport from this organelle. However, the mechanism ensuring the proper co-regulation of these processes has eluded our understanding thus far. We recently identified a physical interaction between the late yeast Golgi Arf activator Sec7p and the PI4-kinase Pik1p, and showed that the two proteins cooperate in the formation of clathrin-coated vesicles. This finding gives the first insight on the coordinated generation of a dual key signal by a small GTPase and a signaling phospholipid at the Golgi. In addition, it opens new perspectives for a better understanding of Golgi maturation through coordinated regulation of highly dynamic lipid and protein composition of this organelle.
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21
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Galacturonosyltransferase (GAUT)1 and GAUT7 are the core of a plant cell wall pectin biosynthetic homogalacturonan:galacturonosyltransferase complex. Proc Natl Acad Sci U S A 2011; 108:20225-30. [PMID: 22135470 DOI: 10.1073/pnas.1112816108] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Plant cell wall pectic polysaccharides are arguably the most complex carbohydrates in nature. Progress in understanding pectin synthesis has been slow due to its complex structure and difficulties in purifying and expressing the low-abundance, Golgi membrane-bound pectin biosynthetic enzymes. Arabidopsis galacturonosyltransferase (GAUT) 1 is an α-1,4-galacturonosyltransferase (GalAT) that synthesizes homogalacturonan (HG), the most abundant pectic polysaccharide. We now show that GAUT1 functions in a protein complex with the homologous GAUT7. Surprisingly, although both GAUT1 and GAUT7 are type II membrane proteins with single N-terminal transmembrane-spanning domains, the N-terminal region of GAUT1, including the transmembrane domain, is cleaved in vivo. This raises the question of how the processed GAUT1 is retained in the Golgi, the site of HG biosynthesis. We show that the anchoring of GAUT1 in the Golgi requires association with GAUT7 to form the GAUT1:GAUT7 complex. Proteomics analyses also identified 12 additional proteins that immunoprecipitate with the GAUT1:GAUT7 complex. This study provides conclusive evidence that the GAUT1:GAUT7 complex is the catalytic core of an HG:GalAT complex and that cell wall matrix polysaccharide biosynthesis occurs via protein complexes. The processing of GAUT1 to remove its N-terminal transmembrane domain and its anchoring in the Golgi by association with GAUT7 provides an example of how specific catalytic domains of plant cell wall biosynthetic glycosyltransferases could be assembled into protein complexes to enable the synthesis of the complex and developmentally and environmentally plastic plant cell wall.
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22
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Hassinen A, Pujol FM, Kokkonen N, Pieters C, Kihlström M, Korhonen K, Kellokumpu S. Functional organization of Golgi N- and O-glycosylation pathways involves pH-dependent complex formation that is impaired in cancer cells. J Biol Chem 2011; 286:38329-38340. [PMID: 21911486 DOI: 10.1074/jbc.m111.277681] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Glycosylation is one of the most common modifications of proteins and lipids and also a major source of biological diversity in eukaryotes. It is critical for many basic cellular functions and recognition events that range from protein folding to cell signaling, immunological defense, and the development of multicellular organisms. Glycosylation takes place mainly in the endoplasmic reticulum and Golgi apparatus and involves dozens of functionally distinct glycosidases and glycosyltransferases. How the functions of these enzymes, which act sequentially and often competitively, are coordinated to faithfully synthesize a vast array of different glycan structures is currently unclear. Here, we investigate the supramolecular organization of the Golgi N- and O-glycosylation pathways in live cells using a FRET flow cytometric quantification approach. We show that the enzymes form enzymatically active homo- and/or heteromeric complexes within each pathway. However, no complexes composed of enzymes that operate in different pathways, were detected, which suggests that the pathways are physically distinct. In addition, we show that complex formation is mediated almost exclusively by the catalytic domains of the interacting enzymes. Our data also suggest that the heteromeric complexes are functionally more important than enzyme homomers. Heteromeric complex formation was found to be dependent on Golgi acidity, markedly impaired in acidification-defective cancer cells, and required for the efficient synthesis of cell surface glycans. Collectively, the results emphasize that the Golgi glycosylation pathways are functionally organized into complexes that are important for glycan synthesis.
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Affiliation(s)
- Antti Hassinen
- Department of Biochemistry and the Finnish Glycoscience Graduate School, University of Oulu, FIN-90014 Oulu, Finland
| | - Francois M Pujol
- Department of Biochemistry and the Finnish Glycoscience Graduate School, University of Oulu, FIN-90014 Oulu, Finland
| | - Nina Kokkonen
- Department of Biochemistry and the Finnish Glycoscience Graduate School, University of Oulu, FIN-90014 Oulu, Finland
| | - Caroline Pieters
- Department of Biochemistry and the Finnish Glycoscience Graduate School, University of Oulu, FIN-90014 Oulu, Finland
| | - Minna Kihlström
- Department of Biochemistry and the Finnish Glycoscience Graduate School, University of Oulu, FIN-90014 Oulu, Finland
| | - Kati Korhonen
- Department of Biochemistry and the Finnish Glycoscience Graduate School, University of Oulu, FIN-90014 Oulu, Finland
| | - Sakari Kellokumpu
- Department of Biochemistry and the Finnish Glycoscience Graduate School, University of Oulu, FIN-90014 Oulu, Finland.
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23
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Freeze HH, Ng BG. Golgi glycosylation and human inherited diseases. Cold Spring Harb Perspect Biol 2011; 3:a005371. [PMID: 21709180 DOI: 10.1101/cshperspect.a005371] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Golgi factory receives custom glycosylates and dispatches its cargo to the correct cellular locations. The process requires importing donor substrates, moving the cargo, and recycling machinery. Correctly glycosylated cargo reflects the Golgi's quality and efficiency. Genetic disorders in the specific equipment (enzymes), donors (nucleotide sugar transporters), or equipment recycling/reorganization components (COG, SEC, golgins) can all affect glycosylation. Dozens of human glycosylation disorders fit these categories. Many other genes, with or without familiar names, well-annotated pedigrees, or likely homologies will join the ranks of glycosylation disorders. Their broad and unpredictable case-by-case phenotypes cross the traditional medical specialty boundaries. The gene functions in patients may be elusive, but their common feature may include altered glycosylation that provide clues to Golgi function. This article focuses on a group of human disorders that affect protein or lipid glycosylation. Readers may find it useful to generalize some of these patient-based, translational observations to their own research.
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Affiliation(s)
- Hudson H Freeze
- Genetic Disease Program, Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
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24
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Alhamidi M, Kjeldsen Buvang E, Fagerheim T, Brox V, Lindal S, Van Ghelue M, Nilssen Ø. Fukutin-related protein resides in the Golgi cisternae of skeletal muscle fibres and forms disulfide-linked homodimers via an N-terminal interaction. PLoS One 2011; 6:e22968. [PMID: 21886772 PMCID: PMC3160285 DOI: 10.1371/journal.pone.0022968] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 07/04/2011] [Indexed: 12/01/2022] Open
Abstract
Limb-Girdle Muscular Dystrophy type 2I (LGMD2I) is an inheritable autosomal, recessive disorder caused by mutations in the FuKutin-Related Protein (FKRP) gene (FKRP) located on chromosome 19 (19q13.3). Mutations in FKRP are also associated with Congenital Muscular Dystrophy (MDC1C), Walker-Warburg Syndrome (WWS) and Muscle Eye Brain disease (MEB). These four disorders share in common an incomplete/aberrant O-glycosylation of the membrane/extracellular matrix (ECM) protein α-dystroglycan. However, further knowledge on the FKRP structure and biological function is lacking, and its intracellular location is controversial. Based on immunogold electron microscopy of human skeletal muscle sections we demonstrate that FKRP co-localises with the middle-to-trans-Golgi marker MG160, between the myofibrils in human rectus femoris muscle fibres. Chemical cross-linking experiments followed by pairwise yeast 2-hybrid experiments, and co-immune precipitation, demonstrate that FKRP can exist as homodimers as well as in large multimeric protein complexes when expressed in cell culture. The FKRP homodimer is kept together by a disulfide bridge provided by the most N-terminal cysteine, Cys6. FKRP contains N-glycan of high mannose and/or hybrid type; however, FKRP N-glycosylation is not required for FKRP homodimer or multimer formation. We propose a model for FKRP which is consistent with that of a Golgi resident type II transmembrane protein.
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Affiliation(s)
- Maisoon Alhamidi
- Division of Child and Adolescent Health, Department of Medical Genetics, University Hospital of North-Norway, Tromsø, Norway
- Department of Clinical Medicine – Medical Genetics, University of Tromsø, Tromsø, Norway
| | | | - Toril Fagerheim
- Division of Child and Adolescent Health, Department of Medical Genetics, University Hospital of North-Norway, Tromsø, Norway
| | - Vigdis Brox
- Division of Child and Adolescent Health, Department of Medical Genetics, University Hospital of North-Norway, Tromsø, Norway
| | - Sigurd Lindal
- Department of Pathology, University Hospital of North-Norway, Tromsø, Norway
- Institute of Medical Biology, University of Tromsø, Tromsø, Norway
| | - Marijke Van Ghelue
- Division of Child and Adolescent Health, Department of Medical Genetics, University Hospital of North-Norway, Tromsø, Norway
- Department of Clinical Medicine – Medical Genetics, University of Tromsø, Tromsø, Norway
| | - Øivind Nilssen
- Division of Child and Adolescent Health, Department of Medical Genetics, University Hospital of North-Norway, Tromsø, Norway
- Department of Clinical Medicine – Medical Genetics, University of Tromsø, Tromsø, Norway
- * E-mail:
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25
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Takematsu H, Yamamoto H, Naito-Matsui Y, Fujinawa R, Tanaka K, Okuno Y, Tanaka Y, Kyogashima M, Kannagi R, Kozutsumi Y. Quantitative transcriptomic profiling of branching in a glycosphingolipid biosynthetic pathway. J Biol Chem 2011; 286:27214-24. [PMID: 21665948 DOI: 10.1074/jbc.m111.234526] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cellular biosynthesis of macromolecules often involves highly branched enzyme pathways, thus cellular regulation of such pathways could be rather difficult. To understand the regulatory mechanism, a systematic approach could be useful. We genetically analyzed a branched biosynthetic pathway for glycosphingolipid (GSL) GM1 using correlation index-based responsible enzyme gene screening (CIRES), a novel quantitative phenotype-genotype correlation analysis. CIRES utilizes transcriptomic profiles obtained from multiple cells. Among a panel of B cell lines, expression of GM1 was negatively correlated with and suppressed by gene expression of CD77 synthase (CD77Syn), whereas no significant positive correlation was found for enzymes actually biosynthesizing GM1. Unexpectedly, a GM1-suppressive phenotype was also observed in the expression of catalytically inactive CD77Syn, ruling out catalytic consumption of lactosylceramide (LacCer) as the main cause for such negative regulation. Rather, CD77Syn seemed to limit other branching reaction(s) by targeting LacCer synthase (LacCerSyn), a proximal enzyme in the pathway, because they were closely localized in the Golgi apparatus and formed a complex. Moreover, turnover of LacCerSyn was accelerated upon CD77Syn expression to globally change the GSL species expressed. Collectively, these data suggest that transcriptomic assessment of macromolecule biosynthetic pathways can disclose a global regulatory mechanism(s) even when unexpected.
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Affiliation(s)
- Hiromu Takematsu
- Laboratory of Membrane Biochemistry and Biophysics, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
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26
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Maccioni HJF, Quiroga R, Ferrari ML. Cellular and molecular biology of glycosphingolipid glycosylation. J Neurochem 2011; 117:589-602. [PMID: 21371037 DOI: 10.1111/j.1471-4159.2011.07232.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Brain tissue is characterized by its high glycosphingolipid content, particularly those containing sialic acid (gangliosides). As a result of this observation, brain tissue was a focus for studies leading to the characterization of the enzymes participating in ganglioside biosynthesis, and their participation in driving the compositional changes that occur in glycolipid expression during brain development. Later on, this focus shifted to the study of cellular aspects of the synthesis, which lead to the identification of the site of synthesis in the neuronal soma and their axonal transport toward the periphery. In this review article, we will focus in subcellular aspects of the biosynthesis of glycosphingolipid oligosaccharides, particularly the mechanisms underlying the trafficking of glycosphingolipid glycosyltransferases from the endoplasmic reticulum to the Golgi, those that promote their retention in the Golgi and those that participate in their topological organization as part of the complex membrane bound machinery for the synthesis of glycosphingolipids.
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Affiliation(s)
- Hugo J F Maccioni
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC (UNC-CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
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27
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Maccioni HJF, Quiroga R, Spessott W. Organization of the synthesis of glycolipid oligosaccharides in the Golgi complex. FEBS Lett 2011; 585:1691-8. [PMID: 21420403 DOI: 10.1016/j.febslet.2011.03.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 03/11/2011] [Accepted: 03/14/2011] [Indexed: 11/28/2022]
Abstract
Glycolipids constitute a complex family of amphipathic molecules structurally characterized by a hydrophilic mono- or oligo-saccharide moiety linked to a hydrophobic ceramide moiety. Due to their asymmetric distribution in cell membranes, exposing the saccharide moiety to the extracytoplasmic side of the cell, glycolipids participate in a variety of cell-cell and cell-ligand interactions. Here we summarize aspects of the cell biology of the stepwise synthesis of the saccharide moiety in the Golgi complex of cells from vertebrates. In particular we refer to the participant glycosyltransferases, with emphasis on their trafficking along the secretory pathway, their retention and organization in the Golgi complex membranes and their dependence on the Golgi complex ultra structural organization for proper function.
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Affiliation(s)
- Hugo J F Maccioni
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC (UNC-CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
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28
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Abstract
Biosynthesis of pectin and hemicelluloses occurs in the Golgi apparatus and is thought to involve spatial regulations and complex formation of biosynthetic enzymes and proteins. We have demonstrated that a combination of heterologous expression of recombinant proteins tagged with fluorescent proteins and live cell imaging with confocal laser scanning microscopy (CLSM) allows efficient visualization of biosynthetic enzymes and proteins in subcellular compartments. We have also successfully utilized bimolecular fluorescence complementation (BiFC) for in situ visualization of protein-protein interactions of pectin biosynthetic enzymes and for the determination of their membrane topology in the Golgi apparatus.
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Affiliation(s)
- Yumiko Sakuragi
- The Department of Plant Biology and Biotechnology, University of Copenhagen, Copenhagen, Denmark
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29
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Hassinen A, Rivinoja A, Kauppila A, Kellokumpu S. Golgi N-glycosyltransferases form both homo- and heterodimeric enzyme complexes in live cells. J Biol Chem 2010; 285:17771-7. [PMID: 20378551 DOI: 10.1074/jbc.m110.103184] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycans (i.e. oligosaccharide chains attached to cellular proteins and lipids) are crucial for nearly all aspects of life, including the development of multicellular organisms. They come in multiple forms, and much of this diversity between molecules, cells, and tissues is generated by Golgi-resident glycosidases and glycosyltransferases. However, their exact mode of functioning in glycan processing is currently unclear. Here we investigate the supramolecular organization of the N-glycosylation pathway in live cells by utilizing the bimolecular fluorescence complementation approach. We show that all four N-glycosylation enzymes tested (beta-1,2-N-acetylglucosaminyltransferase I, beta-1,2-N-acetylglucosaminyltransferase II, 1,4-galactosyltransferase I, and alpha-2,6-sialyltransferase I) form Golgi-localized homodimers. Intriguingly, the same enzymes also formed two distinct and functionally relevant heterodimers between the medial Golgi enzymes beta-1,2-N-acetylglucosaminyltransferase I and beta-1,2-N-acetylglucosaminyltransferase II and the trans-Golgi enzymes 1,4-galactosyltransferase I and alpha-2,6-sialyltransferase I. Given their strict Golgi localization and sequential order of function, the two heterodimeric complexes are probably responsible for the processing and maturation of N-glycans in live cells.
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Affiliation(s)
- Antti Hassinen
- Department of Biochemistry, University of Oulu and the Glycoscience Graduate School Finland, PO Box 3000, Linnanmaa, FIN-90014 Oulu, Finland
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30
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UDP-GalNAc: polypeptide α-N-acetygalactosaminyltransferase 2 Localized on Both cis and trans Side of Golgi Stacks in SGC7901 Cells*. PROG BIOCHEM BIOPHYS 2009. [DOI: 10.3724/sp.j.1206.2008.00299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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31
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Rivinoja A, Hassinen A, Kokkonen N, Kauppila A, Kellokumpu S. Elevated Golgi pH impairs terminal N-glycosylation by inducing mislocalization of Golgi glycosyltransferases. J Cell Physiol 2009; 220:144-54. [PMID: 19277980 DOI: 10.1002/jcp.21744] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Acidic pH of the Golgi lumen is known to be crucial for correct glycosylation, transport and sorting of proteins and lipids during their transit through the organelle. To better understand why Golgi acidity is important for these processes, we have examined here the most pH sensitive events in N-glycosylation by sequentially raising Golgi luminal pH with chloroquine (CQ), a weak base. We show that only a 0.2 pH unit increase (20 microM CQ) is sufficient to markedly impair terminal alpha(2,3)-sialylation of an N-glycosylated reporter protein (CEA), and to induce selective mislocalization of the corresponding alpha(2,3)-sialyltransferase (ST3) into the endosomal compartments. Much higher pH increase was required to impair alpha(2,6)-sialylation, or the proximal glycosylation steps such as beta(1,4)-galactosylation or acquisition of Endo H resistance, and the steady-state localization of the key enzymes responsible for these modifications (ST6, GalT I, MANII). The overall Golgi morphology also remained unaltered, except when Golgi pH was raised close to neutral. By using transmembrane domain chimeras between the ST6 and ST3, we also show that the luminal domain of the ST6 is mainly responsible for its less pH sensitive localization in the Golgi. Collectively, these results emphasize that moderate Golgi pH alterations such as those detected in cancer cells can impair N-glycosylation by inducing selective mislocalization of only certain Golgi glycosyltransferases.
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Affiliation(s)
- Antti Rivinoja
- Department of Biochemistry and The Finnish Glycoscience Graduate School, University of Oulu, Oulu, Finland
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32
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Shifley ET, Cole SE. Lunatic fringe protein processing by proprotein convertases may contribute to the short protein half-life in the segmentation clock. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:2384-90. [DOI: 10.1016/j.bbamcr.2008.07.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 07/10/2008] [Accepted: 07/11/2008] [Indexed: 12/18/2022]
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33
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Marathe DD, Chandrasekaran EV, Lau JTY, Matta KL, Neelamegham S. Systems-level studies of glycosyltransferase gene expression and enzyme activity that are associated with the selectin binding function of human leukocytes. FASEB J 2008; 22:4154-67. [PMID: 18716032 DOI: 10.1096/fj.07-104257] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The application of systems biology methods in the emerging field of glycomics requires the collection and integration of glycosyltransferase data at the gene and enzyme level for the purpose of hypothesis generation. We systematically examined the relationship between gene expression, glycosyltransferase activity, glycan expression, and selectin-binding function in different systems, including human neutrophils, undifferentiated HL-60 (human promyelocytic cells), differentiated HL-60, and HL-60 synchronized in specific growth phases. Results demonstrate that 1) the sLe(X) (sialyl-Lewis-X) epitope is expressed in P-selectin glycoprotein ligand-1 (PSGL-1) from neutrophils at higher levels compared with HL-60. This variation may be due to differences in the relative activities of alpha1,3-fucosyltransferases and alpha2,3-sialyltransferases in these two cell types. 2) HL-60 cell differentiation along granulocyte lineage increased the activity of beta1,4GalT and beta1,3GlcNAcT by 1.6- to 3.2-fold. This may contribute to LacNAc chain extension as evidenced by the 1.7-fold increase in DSA-lectin (lectin recognizing LacNAc) binding to cells after differentiation. 3) The activity of enzymes contributing to sLe(X) formation in leukocytes likely varies as ST3[Galbeta1,4GlcNAc] < or = alpha1,3FT[sialyl-LacNAc] < beta1,3GlcNAcT. 4) O-glycan specific glycosyltransferase activity does not undergo periodic variation with cell cycle phases. Overall, gene expression and enzyme activity data combined with knowledge of biochemistry can predict the resulting glycan structures and yield viable experimentally testable hypothesis.
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Affiliation(s)
- Dhananjay D Marathe
- Chemical and Biological Engineering State University of New York at Buffalo, Buffalo, NY 14260, USA
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34
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Abstract
Gangliosides are a family of glycolipids characterized by containing a variable number of sialic acid residues. Nearly, all animal cells contain at least some class of ganglioside in their membranes, but membranes from the CNS are characterized by their high content of these lipids. The synthesis of the oligosaccharide moiety of glycolipids is carried out in the Golgi complex. In this study, I will discuss the cellular and molecular basis of the organization of the glycosylating machinery in the Golgi complex, with particular attention to the mutual relationships, sub-Golgi localization, and intracellular trafficking of glycolipid glycosyltransferases, and to their relationships with the corresponding glycolipid acceptors and sugar nucleotide donors. I will also discuss how the organization of the glycosylating machinery in the Golgi may adapt to events controlling glycolipid expression.
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Affiliation(s)
- Hugo J F Maccioni
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC (UNC-CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina.
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35
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Saint-Jore-Dupas C, Nebenführ A, Boulaflous A, Follet-Gueye ML, Plasson C, Hawes C, Driouich A, Faye L, Gomord V. Plant N-glycan processing enzymes employ different targeting mechanisms for their spatial arrangement along the secretory pathway. THE PLANT CELL 2006; 18:3182-200. [PMID: 17138701 PMCID: PMC1693952 DOI: 10.1105/tpc.105.036400] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Revised: 08/31/2006] [Accepted: 11/02/2006] [Indexed: 05/12/2023]
Abstract
The processing of N-linked oligosaccharides in the secretory pathway requires the sequential action of a number of glycosidases and glycosyltransferases. We studied the spatial distribution of several type II membrane-bound enzymes from Glycine max, Arabidopsis thaliana, and Nicotiana tabacum. Glucosidase I (GCSI) localized to the endoplasmic reticulum (ER), alpha-1,2 mannosidase I (ManI) and N-acetylglucosaminyltransferase I (GNTI) both targeted to the ER and Golgi, and beta-1,2 xylosyltransferase localized exclusively to Golgi stacks, corresponding to the order of expected function. ManI deletion constructs revealed that the ManI transmembrane domain (TMD) contains all necessary targeting information. Likewise, GNTI truncations showed that this could apply to other type II enzymes. A green fluorescent protein chimera with ManI TMD, lengthened by duplicating its last seven amino acids, localized exclusively to the Golgi and colocalized with a trans-Golgi marker (ST52-mRFP), suggesting roles for protein-lipid interactions in ManI targeting. However, the TMD lengths of other plant glycosylation enzymes indicate that this mechanism cannot apply to all enzymes in the pathway. In fact, removal of the first 11 amino acids of the GCSI cytoplasmic tail resulted in relocalization from the ER to the Golgi, suggesting a targeting mechanism relying on protein-protein interactions. We conclude that the localization of N-glycan processing enzymes corresponds to an assembly line in the early secretory pathway and depends on both TMD length and signals in the cytoplasmic tail.
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Affiliation(s)
- Claude Saint-Jore-Dupas
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6037, IFRMP 23, GDR 2590, UFR des Sciences, Université de Rouen, 76821 Mont-Saint-Aignan Cedex, France
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36
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Abstract
The spectrum of all glycan structures--the glycome--is immense. In humans, its size is orders of magnitude greater than the number of proteins that are encoded by the genome, one percent of which encodes proteins that make, modify, localize or bind sugar chains, which are known as glycans. In the past decade, over 30 genetic diseases have been identified that alter glycan synthesis and structure, and ultimately the function of nearly all organ systems. Many of the causal mutations affect key biosynthetic enzymes, but more recent discoveries point to defects in chaperones and Golgi-trafficking complexes that impair several glycosylation pathways. As more glycosylation disorders and patients with these disorders are identified, the functions of the glycome are starting to be revealed.
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Affiliation(s)
- Hudson H Freeze
- Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, California 92037, USA.
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37
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Ercan A, Panico M, Sutton-Smith M, Dell A, Morris HR, Matta KL, Gay DF, West CM. Molecular characterization of a novel UDP-galactose:fucoside alpha3-galactosyltransferase that modifies Skp1 in the cytoplasm of Dictyostelium. J Biol Chem 2006; 281:12713-21. [PMID: 16495217 DOI: 10.1074/jbc.m513664200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Skp1 is a nucleocytoplasmic protein that is post-translationally modified by a pentasaccharide, Gal alpha1,Gal alpha1,3Fuc alpha1,2Gal-beta1,3GlcNAc alpha1O-, at a 4-hydroxylated derivative of Pro-143 in the amebazoan Dictyostelium discoideum. An enzymatic activity that catalyzes formation of the Gal alpha1,3Fuc linkage by transfer of Gal from UDP-alphaGal to Fuc alpha1,2Gal beta1,3GlcNAc alpha1O-benzyl, or the corresponding glycoform of Skp1, was described previously in cytosolic extracts of Dictyostelium. A protein GT78 associated with this activity has been purified to chromatographic homogeneity. In-gel tryptic digestion followed by nano-liquid chromatography-mass spectrometry on a quadrupole time-of-flight geometry instrument with data-dependent tandem mass spectrometry acquisition yielded a number of peptide fragmentation spectra, nine of which were manually de novo sequenced and found to map onto a predicted 3-exon gene of unknown function on chromosome 4. GT78 is predicted to comprise 648 amino acids with an N-terminal glycosyltransferase and a C-terminal beta-propeller domain. Overexpression of GT78 with a His6-tag resulted in a 120-fold increase in GalT-activity in cytosolic extracts, and purified His6-GT78 exhibited alpha3GalT-activity toward a synthetic acceptor substrate. Expression of the truncated N-terminal region confirmed the predicted catalytic activity of this domain. Disruption of the GT78 gene led to a loss of enzyme activity in extracts and accumulation of the non-galactosylated isoform of Skp1 in cells. GT78 therefore represents the Skp1 alpha3GalT, and its mechanism conforms to the sequential model of Skp1 glycosylation in the cytoplasm shown for earlier enzymes in the pathway. Informatics studies suggest that related catalytic domains are expressed in the Golgi or cytoplasm of plants, other protozoans, and animals.
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Affiliation(s)
- Altan Ercan
- Department of Biochemistry & Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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Wopereis S, Lefeber DJ, Morava E, Wevers RA. Mechanisms in protein O-glycan biosynthesis and clinical and molecular aspects of protein O-glycan biosynthesis defects: a review. Clin Chem 2006; 52:574-600. [PMID: 16497938 DOI: 10.1373/clinchem.2005.063040] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Genetic diseases that affect the biosynthesis of protein O-glycans are a rapidly growing group of disorders. Because this group of disorders does not have a collective name, it is difficult to get an overview of O-glycosylation in relation to human health and disease. Many patients with an unsolved defect in N-glycosylation are found to have an abnormal O-glycosylation as well. It is becoming increasingly evident that the primary defect of these disorders is not necessarily localized in one of the glycan-specific transferases, but can likewise be found in the biosynthesis of nucleotide sugars, their transport to the endoplasmic reticulum (ER)/Golgi, and in Golgi trafficking. Already, disorders in O-glycan biosynthesis form a substantial group of genetic diseases. In view of the number of genes involved in O-glycosylation processes and the increasing scientific interest in congenital disorders of glycosylation, it is expected that the number of identified diseases in this group will grow rapidly over the coming years. CONTENT We first discuss the biosynthesis of protein O-glycans from their building blocks to their secretion from the Golgi. Subsequently, we review 24 different genetic disorders in O-glycosylation and 10 different genetic disorders that affect both N- and O-glycosylation. The key clinical, metabolic, chemical, diagnostic, and genetic features are described. Additionally, we describe methods that can be used in clinical laboratory screening for protein O-glycosylation biosynthesis defects and their pitfalls. Finally, we introduce existing methods that might be useful for unraveling O-glycosylation defects in the future.
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Affiliation(s)
- Suzan Wopereis
- Laboratory of Pediatrics and Neurology and Department of Pediatrics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
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39
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Kartberg F, Elsner M, Fröderberg L, Asp L, Nilsson T. Commuting between Golgi cisternae—Mind the GAP! BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1744:351-63. [PMID: 15939491 DOI: 10.1016/j.bbamcr.2005.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Revised: 04/29/2005] [Accepted: 05/03/2005] [Indexed: 11/18/2022]
Abstract
Intracellular transport has remained central to cell biology now for more than 40 years. Despite this, we still lack an overall mechanistic framework that describes transport in different parts of the cell. In the secretory pathway, basic questions, such as how biosynthetic cargo traverses the pathway, are still debated. Historically, emphasis was first put on interpreting function from morphology at the ultrastructural level revealing membrane structures such as the transitional ER, vesicular carriers, vesicular tubular clusters, Golgi cisternae, Golgi stacks and the Golgi ribbon. This emphasis on morphology later switched to biochemistry and yeast genetics yielding many of the key molecular players and their associated functions that we know today. More recently, microscopy studies of living cells incorporating biophysics and system analysis has proven useful and is often used to readdress earlier findings, sometimes with surprising outcomes.
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Affiliation(s)
- Fredrik Kartberg
- Department of Medical Biochemistry, Göteborg University, 413 90 Göteborg, Sweden
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Fritz TA, Hurley JH, Trinh LB, Shiloach J, Tabak LA. The beginnings of mucin biosynthesis: the crystal structure of UDP-GalNAc:polypeptide alpha-N-acetylgalactosaminyltransferase-T1. Proc Natl Acad Sci U S A 2004; 101:15307-12. [PMID: 15486088 PMCID: PMC524453 DOI: 10.1073/pnas.0405657101] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Accepted: 09/10/2004] [Indexed: 11/18/2022] Open
Abstract
UDP-GalNAc:polypeptide alpha-N-acetylgalactosaminyltransferases (ppGaNTases) initiate the formation of mucin-type, O-linked glycans by catalyzing the transfer of alpha-N-acetylgalactosamine from UDP-GalNAc to Ser or Thr residues of core proteins to form the Tn antigen (GalNAc-alpha-1-O-Ser/Thr). ppGaNTases are unique among glycosyltransferases in containing a C-terminal lectin domain. We present the x-ray crystal structure of a ppGaNTase, murine ppGaNTase-T1, and show that it folds to form distinct catalytic and lectin domains. The association of the two domains forms a large cleft in the surface of the enzyme that contains a Mn2+ ion complexed by invariant D209 and H211 of the "DXH" motif and by invariant H344. Each of the three potential lectin domain carbohydrate-binding sites (alpha, beta, and gamma) is located on the active-site face of the enzyme, suggesting a mechanism by which the transferase may accommodate multiple conformations of glycosylated acceptor substrates. A model of a mucin 1 glycopeptide substrate bound to the enzyme shows that the spatial separation between the lectin alpha site and a modeled active site UDP-GalNAc is consistent with the in vitro pattern of glycosylation observed for this peptide catalyzed by ppGaNTase-T1. The structure also provides a template for the larger ppGaNTase family, and homology models of several ppGaNTase isoforms predict dramatically different surface chemistries consistent with isoform-selective acceptor substrate recognition.
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Affiliation(s)
- Timothy A Fritz
- Section on Biological Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA
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