1
|
Humeidi R, Oshiro-Rapley N, Gu X, An JS, Ananthakrishnan AN, Creasey EA, Daly MJ, Schreiber SL, Graham DB, Seyedsayamdost MR, Xavier RJ. The Ulcerative Colitis-Associated Gene NXPE1 Catalyzes Glycan Modifications on Colonic Mucin. J Am Chem Soc 2025; 147:10618-10628. [PMID: 40067145 PMCID: PMC12076216 DOI: 10.1021/jacs.5c00769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2025]
Abstract
Colonic mucus forms a first line of defense against bacterial invasion while providing nutrition to support coinhabiting microbes in the gut. Mucus is composed of polymeric networks of mucin proteins, which are heavily modified post-translationally. The full compendium of enzymes responsible for these modifications and their roles in health and disease remain incompletely understood. Herein, we determine the biochemical function of NXPE1, a gene implicated in ulcerative colitis (UC), and demonstrate that it encodes an acetyltransferase that modifies mucin glycans. Specifically, NXPE1 utilizes acetyl-CoA to regioselectively modify the mucus sialic acid, 5-N-acetylneuraminic acid (Neu5Ac), at the 9-OH group to generate 9-O-acetylated Neu5Ac (Neu5,9Ac2). We further demonstrate that colonic organoids derived from donors harboring the missense variant NXPE1 G353R, which is protective against UC, exhibit severely impaired acetylation of Neu5Ac on mucins. Together, our findings support a model in which NXPE1 masks the alcohols of mucus sialoglycans via acetylation, which is important for modulating mucus barrier properties that limit interactions with commensal microbes.
Collapse
Affiliation(s)
- Ranad Humeidi
- Program for Chemistry & Chemical Biology, Harvard Medical School, Boston, MA 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02141, USA
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Noriko Oshiro-Rapley
- Broad Institute of MIT and Harvard, Cambridge, MA 02141, USA
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Xiebin Gu
- Broad Institute of MIT and Harvard, Cambridge, MA 02141, USA
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Joon Soo An
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Ashwin N. Ananthakrishnan
- Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
- Division of Gastroenterology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Elizabeth A. Creasey
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Mark J. Daly
- Broad Institute of MIT and Harvard, Cambridge, MA 02141, USA
- Analytic and Translational Genetics Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Stuart L. Schreiber
- Broad Institute of MIT and Harvard, Cambridge, MA 02141, USA
- Department of Chemistry & Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Daniel B. Graham
- Broad Institute of MIT and Harvard, Cambridge, MA 02141, USA
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
- Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Mohammad R. Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Ramnik J. Xavier
- Broad Institute of MIT and Harvard, Cambridge, MA 02141, USA
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
- Center for the Study of Inflammatory Bowel Disease, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| |
Collapse
|
2
|
Herrera-Marcos LV, Sahali D, Ollero M. 9-O Acetylated Gangliosides in Health and Disease. Biomolecules 2023; 13:biom13050827. [PMID: 37238697 DOI: 10.3390/biom13050827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/05/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Glycosphingolipids comprise a lipid class characterized by the presence of sugar moieties attached to a ceramide backbone. The role of glycosphingolipids in pathophysiology has gained relevance in recent years in parallel with the development of analytical technologies. Within this vast family of molecules, gangliosides modified by acetylation represent a minority. Described for the first time in the 1980s, their relation to pathologies has resulted in increased interest in their function in normal and diseased cells. This review presents the state of the art on 9-O acetylated gangliosides and their link to cellular disorders.
Collapse
Affiliation(s)
| | - Dil Sahali
- Univ Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France
- AP-HP, Hôpitaux Universitaires Henri Mondor, Service de Néphrologie, F-94010 Creteil, France
| | - Mario Ollero
- Univ Paris Est Creteil, INSERM, IMRB, F-94010 Creteil, France
| |
Collapse
|
3
|
Visser EA, Moons SJ, Timmermans SBPE, de Jong H, Boltje TJ, Büll C. Sialic acid O-acetylation: From biosynthesis to roles in health and disease. J Biol Chem 2021; 297:100906. [PMID: 34157283 PMCID: PMC8319020 DOI: 10.1016/j.jbc.2021.100906] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/16/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023] Open
Abstract
Sialic acids are nine-carbon sugars that frequently cap glycans at the cell surface in cells of vertebrates as well as cells of certain types of invertebrates and bacteria. The nine-carbon backbone of sialic acids can undergo extensive enzymatic modification in nature and O-acetylation at the C-4/7/8/9 position in particular is widely observed. In recent years, the detection and analysis of O-acetylated sialic acids have advanced, and sialic acid-specific O-acetyltransferases (SOATs) and O-acetylesterases (SIAEs) that add and remove O-acetyl groups, respectively, have been identified and characterized in mammalian cells, invertebrates, bacteria, and viruses. These advances now allow us to draw a more complete picture of the biosynthetic pathway of the diverse O-acetylated sialic acids to drive the generation of genetically and biochemically engineered model cell lines and organisms with altered expression of O-acetylated sialic acids for dissection of their roles in glycoprotein stability, development, and immune recognition, as well as discovery of novel functions. Furthermore, a growing number of studies associate sialic acid O-acetylation with cancer, autoimmunity, and infection, providing rationale for the development of selective probes and inhibitors of SOATs and SIAEs. Here, we discuss the current insights into the biosynthesis and biological functions of O-acetylated sialic acids and review the evidence linking this modification to disease. Furthermore, we discuss emerging strategies for the design, synthesis, and potential application of unnatural O-acetylated sialic acids and inhibitors of SOATs and SIAEs that may enable therapeutic targeting of this versatile sialic acid modification.
Collapse
Affiliation(s)
- Eline A Visser
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Sam J Moons
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Suzanne B P E Timmermans
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Heleen de Jong
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Thomas J Boltje
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands.
| | - Christian Büll
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; Hubrecht Institute, Utrecht, the Netherlands.
| |
Collapse
|
4
|
Targeting O-Acetyl-GD2 Ganglioside for Cancer Immunotherapy. J Immunol Res 2017; 2017:5604891. [PMID: 28154831 PMCID: PMC5244029 DOI: 10.1155/2017/5604891] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/18/2016] [Accepted: 12/08/2016] [Indexed: 12/29/2022] Open
Abstract
Target selection is a key feature in cancer immunotherapy, a promising field in cancer research. In this respect, gangliosides, a broad family of structurally related glycolipids, were suggested as potential targets for cancer immunotherapy based on their higher abundance in tumors when compared with the matched normal tissues. GD2 is the first ganglioside proven to be an effective target antigen for cancer immunotherapy with the regulatory approval of dinutuximab, a chimeric anti-GD2 therapeutic antibody. Although the therapeutic efficacy of anti-GD2 monoclonal antibodies is well documented, neuropathic pain may limit its application. O-Acetyl-GD2, the O-acetylated-derivative of GD2, has recently received attention as novel antigen to target GD2-positive cancers. The present paper examines the role of O-acetyl-GD2 in tumor biology as well as the available preclinical data of anti-O-acetyl-GD2 monoclonal antibodies. A discussion on the relevance of O-acetyl-GD2 in chimeric antigen receptor T cell therapy development is also included.
Collapse
|
5
|
Baumann AMT, Bakkers MJG, Buettner FFR, Hartmann M, Grove M, Langereis MA, de Groot RJ, Mühlenhoff M. 9-O-Acetylation of sialic acids is catalysed by CASD1 via a covalent acetyl-enzyme intermediate. Nat Commun 2015; 6:7673. [PMID: 26169044 PMCID: PMC4510713 DOI: 10.1038/ncomms8673] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 06/01/2015] [Indexed: 12/13/2022] Open
Abstract
Sialic acids, terminal sugars of glycoproteins and glycolipids, play important roles in development, cellular recognition processes and host–pathogen interactions. A common modification of sialic acids is 9-O-acetylation, which has been implicated in sialoglycan recognition, ganglioside biology, and the survival and drug resistance of acute lymphoblastic leukaemia cells. Despite many functional implications, the molecular basis of 9-O-acetylation has remained elusive thus far. Following cellular approaches, including selective gene knockout by CRISPR/Cas genome editing, we here show that CASD1—a previously identified human candidate gene—is essential for sialic acid 9-O-acetylation. In vitro assays with the purified N-terminal luminal domain of CASD1 demonstrate transfer of acetyl groups from acetyl-coenzyme A to CMP-activated sialic acid and formation of a covalent acetyl-enzyme intermediate. Our study provides direct evidence that CASD1 is a sialate O-acetyltransferase and serves as key enzyme in the biosynthesis of 9-O-acetylated sialoglycans. 9-O-Acetylation is one of the most common modifications of sialic acids, implicated in sialoglycan recognition and ganglioside biology. Here, the authors show that the key enzyme for the biosynthesis of 9-O-acetylated sialoglycans is CASD1, which uses CMP-activated sialic acid as acceptor substrate.![]()
Collapse
Affiliation(s)
- Anna-Maria T Baumann
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
| | - Mark J G Bakkers
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Falk F R Buettner
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
| | - Maike Hartmann
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
| | - Melanie Grove
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
| | - Martijn A Langereis
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Raoul J de Groot
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Martina Mühlenhoff
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
| |
Collapse
|
6
|
Langereis MA, Bakkers MJG, Deng L, Padler-Karavani V, Vervoort SJ, Hulswit RJG, van Vliet ALW, Gerwig GJ, de Poot SAH, Boot W, van Ederen AM, Heesters BA, van der Loos CM, van Kuppeveld FJM, Yu H, Huizinga EG, Chen X, Varki A, Kamerling JP, de Groot RJ. Complexity and Diversity of the Mammalian Sialome Revealed by Nidovirus Virolectins. Cell Rep 2015; 11:1966-78. [PMID: 26095364 PMCID: PMC5292239 DOI: 10.1016/j.celrep.2015.05.044] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 05/01/2015] [Accepted: 05/22/2015] [Indexed: 12/23/2022] Open
Abstract
Sialic acids (Sias), 9-carbon-backbone sugars, are among the most complex and versatile molecules of life. As terminal residues of glycans on proteins and lipids, Sias are key elements of glycotopes of both cellular and microbial lectins and thus act as important molecular tags in cell recognition and signaling events. Their functions in such interactions can be regulated by post-synthetic modifications, the most common of which is differential Sia-O-acetylation (O-Ac-Sias). The biology of O-Ac-Sias remains mostly unexplored, largely because of limitations associated with their specific in situ detection. Here, we show that dual-function hemagglutinin-esterase envelope proteins of nidoviruses distinguish between a variety of closely related O-Ac-Sias. By using soluble forms of hemagglutinin-esterases as lectins and sialate-O-acetylesterases, we demonstrate differential expression of distinct O-Ac-sialoglycan populations in an organ-, tissue- and cell-specific fashion. Our findings indicate that programmed Sia-O-acetylation/de-O-acetylation may be critical to key aspects of cell development, homeostasis, and/or function. Virolectins detect and distinguish between closely related O-Ac-Sias in situ O-Ac-sialoglycans occur in nature in a diversity not appreciated so far O-Ac-Sias are differentially expressed in a species-, tissue-, and cell-specific fashion There is extensive cell-to-cell variability in O-Ac-Sia expression in vivo and in vitro
Collapse
Affiliation(s)
- Martijn A Langereis
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Mark J G Bakkers
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Lingquan Deng
- Glycobiology Research and Training Center, Departments of Medicine and Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0687, USA
| | - Vered Padler-Karavani
- Glycobiology Research and Training Center, Departments of Medicine and Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0687, USA
| | - Stephin J Vervoort
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Ruben J G Hulswit
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Arno L W van Vliet
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Gerrit J Gerwig
- Bio-Organic Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Stefanie A H de Poot
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Willemijn Boot
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Anne Marie van Ederen
- Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Balthasar A Heesters
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Chris M van der Loos
- Department of Cardiovascular Pathology, Free University Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Frank J M van Kuppeveld
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Hai Yu
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Eric G Huizinga
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Xi Chen
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Ajit Varki
- Glycobiology Research and Training Center, Departments of Medicine and Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0687, USA
| | - Johannis P Kamerling
- Bio-Organic Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Raoul J de Groot
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands.
| |
Collapse
|
7
|
Hayes CA, Doohan R, Kirkley D, Leister K, Harhen B, Savage AV, Karlsson NG. Cross validation of liquid chromatography-mass spectrometry and lectin array for monitoring glycosylation in fed-batch glycoprotein production. Mol Biotechnol 2012; 51:272-82. [PMID: 22048797 DOI: 10.1007/s12033-011-9465-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Glycosylation analysis of recombinant glycoproteins is of importance for the biopharmaceutical industry and the production of glycoprotein pharmaceuticals. A commercially available lectin array technology was evaluated for its ability to present a reproducible fingerprint of a recombinant CTLY4-IgG fusion glycoprotein expressed in large scale CHO-cell fermentation. The glycosylation prediction from the array was compared to traditional negative mode capillary LC-MS of released oligosaccharides. It was shown that both methods provide data that allow samples to be distinguished by their glycosylation pattern. This included information about sialylation, the presence of reducing terminal galactose β1-, terminal N-acetylglucosamine β1-, and antennary distribution. With both methods it was found that a general trend of increased sialylation was associated with an increase of the antenna and reduced amount of terminal galactose β1-, while N-acetylglucosamine β1- was less affected. LC-MS, but not the lectin array, provided valuable information about the sialic acid isoforms present, including N-acetylneuraminic acid, N-glycolylneuraminic acid and their O-acetylated versions. Detected small amounts of high-mannose structures by LC-MS correlated with the detection of the same epitope by the lectin array.
Collapse
|
8
|
Romero-Ramírez L, García-Álvarez I, Campos-Olivas R, Gilbert M, Goneau MF, Fernández-Mayoralas A, Nieto-Sampedro M. Specific synthesis of neurostatin and gangliosides O-acetylated in the outer sialic acids using a sialate transferase. PLoS One 2012; 7:e49983. [PMID: 23226505 PMCID: PMC3513307 DOI: 10.1371/journal.pone.0049983] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 10/16/2012] [Indexed: 11/28/2022] Open
Abstract
Gangliosides are sialic acid containing glycosphingolipids, commonly found on the outer leaflet of the plasma membrane. O-acetylation of sialic acid hydroxyl groups is one of the most common modifications in gangliosides. Studies on the biological activity of O-acetylated gangliosides have been limited by their scarcity in nature. This comparatively small change in ganglioside structure causes major changes in their physiological properties. When the ganglioside GD1b was O-acetylated in the outer sialic acid, it became the potent inhibitor of astroblast and astrocytoma proliferation called Neurostatin. Although various chemical and enzymatic methods to O-acetylate commercial gangliosides have been described, O-acetylation was nonspecific and produced many side-products that reduced the yield. An enzyme with O-acetyltransferase activity (SOAT) has been previously cloned from the bacteria Campylobacter jejuni. This enzyme catalyzed the acetylation of oligosaccharide-bound sialic acid, with high specificity for terminal alpha-2,8-linked residues. Using this enzyme and commercial gangliosides as starting material, we have specifically O-acetylated the gangliosides' outer sialic acids, to produce the corresponding gangliosides specifically O-acetylated in the sialic acid bound in alpha-2,3 and alpha-2,8 residues. We demonstrate here that O-acetylation occurred specifically in the C-9 position of the sialic acid. In summary, we present a new method of specific O-acetylation of ganglioside sialic acids that permits the large scale preparation of these modified glycosphingolipids, facilitating both, the study of their mechanism of antitumoral action and their use as therapeutic drugs for treating glioblastoma multiform (GBM) patients.
Collapse
|
9
|
Abstract
Sialic acids have a pivotal functional impact in many biological interactions such as virus attachment, cellular adhesion, regulation of proliferation, and apoptosis. A common modification of sialic acids is O-acetylation. O-Acetylated sialic acids occur in bacteria and parasites and are also receptor determinants for a number of viruses. Moreover, they have important functions in embryogenesis, development, and immunological processes. O-Acetylated sialic acids represent cancer markers, as shown for acute lymphoblastic leukemia, and they are known to play significant roles in the regulation of ganglioside-mediated apoptosis. Expression of O-acetylated sialoglycans is regulated by sialic acid-specific O-acetyltransferases and O-acetylesterases. Recent developments in the identification of the enigmatic sialic acid-specific O-acetyltransferase are discussed.
Collapse
Affiliation(s)
- Chitra Mandal
- Cancer and Cell Biology, Council of Scientific and Industrial Research - Indian Institute of Chemical Biology, 4 Raja S.C. Mallick Road, Kolkata, 700 032 India
| | - Reinhard Schwartz-Albiez
- Department of Translational Immunology, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Reinhard Vlasak
- Department of Molecular Biology, University Salzburg, Billrothstr 11, 5020 Salzburg, Austria
| |
Collapse
|
10
|
Merrill AH. Sphingolipid and glycosphingolipid metabolic pathways in the era of sphingolipidomics. Chem Rev 2011; 111:6387-422. [PMID: 21942574 PMCID: PMC3191729 DOI: 10.1021/cr2002917] [Citation(s) in RCA: 588] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Indexed: 12/15/2022]
Affiliation(s)
- Alfred H Merrill
- School of Biology, and the Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332-0230, USA.
| |
Collapse
|
11
|
Mandal C, Mandal C, Chandra S, Schauer R, Mandal C. Regulation of O-acetylation of sialic acids by sialate-O-acetyltransferase and sialate-O-acetylesterase activities in childhood acute lymphoblastic leukemia. Glycobiology 2011; 22:70-83. [DOI: 10.1093/glycob/cwr106] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
|
12
|
Arming S, Wipfler D, Mayr J, Merling A, Vilas U, Schauer R, Schwartz-Albiez R, Vlasak R. The human Cas1 protein: a sialic acid-specific O-acetyltransferase? Glycobiology 2011; 21:553-64. [PMID: 20947662 PMCID: PMC7108626 DOI: 10.1093/glycob/cwq153] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Sialic acids are important sugars at the reducing end of glycoproteins and glycolipids. They are among many other functions involved in cell-cell interactions, host-pathogen recognition and the regulation of serum half-life of glycoproteins. An important modification of sialic acids is O-acetylation, which can alter or mask the biological properties of the parent sialic acid molecule. The nature of mammalian sialate-O-acetyltransferases (EC 2.3.1.45) involved in their biosynthesis is still unknown. We have identified the human CasD1 (capsule structure1 domain containing 1) gene as a candidate to encode the elusive enzyme. The human CasD1 gene encodes a protein with a serine-glycine-asparagine-histidine hydrolase domain and a hydrophobic transmembrane domain. Expression of the Cas1 protein tagged with enhanced green fluorescent protein in mammalian and insect cells directed the protein to the medial and trans-cisternae of the Golgi. Overexpression of the Cas1 protein in combination with α-N-acetyl-neuraminide α-2,8-sialyltransferase 1 (GD3 synthase) resulted in an up to 40% increased biosynthesis of 7-O-acetylated ganglioside GD3. By quantitative real-time polymerase chain reaction, we found up to 5-fold increase in CasD1 mRNA in tumor cells overexpressing O-Ac-GD3. CasD1-specific small interfering RNA reduced O-acetylation in tumor cells. These results suggest that the human Cas1 protein is directly involved in O-acetylation of α2-8-linked sialic acids.
Collapse
Affiliation(s)
- Sigrid Arming
- Department of Molecular Biology, University Salzburg, Austria
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Parker RB, Kohler JJ. Regulation of intracellular signaling by extracellular glycan remodeling. ACS Chem Biol 2010; 5:35-46. [PMID: 19968325 DOI: 10.1021/cb9002514] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The plasma membrane of eukaryotic cells is coated with carbohydrates. By virtue of their extracellular position and recognizable chemical features, cell surface glycans mediate many receptor-ligand interactions. Recently, mammalian extracellular hydrolytic enzymes have been shown to modify the structure of cell surface glycans and consequently alter their binding properties. These cell surface glycan remodeling events can cause rapid changes in critical signal transduction phenomena. This Review highlights recent studies on the roles of eukaryotic extracellular sialidases, sulfatases, and a deacetylase in regulation of intracellular signaling. We also describe possible therapies that target extracellular glycan remodeling processes and discuss the potential for new discoveries in this area.
Collapse
Affiliation(s)
- Randy B. Parker
- Division of Translational Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9185
| | - Jennifer J. Kohler
- Division of Translational Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9185
| |
Collapse
|
14
|
Cariappa A, Takematsu H, Liu H, Diaz S, Haider K, Boboila C, Kalloo G, Connole M, Shi HN, Varki N, Varki A, Pillai S. B cell antigen receptor signal strength and peripheral B cell development are regulated by a 9-O-acetyl sialic acid esterase. ACTA ACUST UNITED AC 2008; 206:125-38. [PMID: 19103880 PMCID: PMC2626685 DOI: 10.1084/jem.20081399] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We show that the enzymatic acetylation and deacetylation of a cell surface carbohydrate controls B cell development, signaling, and immunological tolerance. Mice with a mutation in sialate:O-acetyl esterase, an enzyme that specifically removes acetyl moieties from the 9-OH position of α2–6-linked sialic acid, exhibit enhanced B cell receptor (BCR) activation, defects in peripheral B cell development, and spontaneously develop antichromatin autoantibodies and glomerular immune complex deposits. The 9-O-acetylation state of sialic acid regulates the function of CD22, a Siglec that functions in vivo as an inhibitor of BCR signaling. These results describe a novel catalytic regulator of B cell signaling and underscore the crucial role of inhibitory signaling in the maintenance of immunological tolerance in the B lineage.
Collapse
Affiliation(s)
- Annaiah Cariappa
- Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Furukawa K, Aixinjueluo W, Kasama T, Ohkawa Y, Yoshihara M, Ohmi Y, Tajima O, Suzumura A, Kittaka D, Furukawa K. Disruption of GM2/GD2 synthase gene resulted in overt expression of 9-O-acetyl GD3 irrespective of Tis21. J Neurochem 2008; 105:1057-66. [PMID: 18194438 PMCID: PMC2408653 DOI: 10.1111/j.1471-4159.2008.05232.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2007] [Accepted: 12/20/2007] [Indexed: 11/28/2022]
Abstract
GM2/GD2 synthase gene knockout mice lack all complex gangliosides, which are abundantly expressed in the nervous systems of vertebrates. In turn, they have increased precursor structures GM3 and GD3, probably replacing the roles of the depleted complex gangliosides. In this study, we found that 9-O-acetyl GD3 is also highly expressed as one of the major glycosphingolipids accumulating in the nervous tissues of the mutant mice. The identity of the novel component was confirmed by neuraminidase treatment, thin layer chromatography-immunostaining, two-dimensional thin layer chromatography with base treatment, and mass spectrometry. All candidate factors reported to be possible inducer of 9-O- acetylation, such as bitamine D binding protein, acetyl CoA transporter, or O-acetyl ganglioside synthase were not up-regulated. Tis21 which had been reported to be a 9-O-acetylation inducer was partially down-regulated in the null mutants, suggesting that Tis21 is not involved in the induction of 9-O-acetyl-GD3 and that accumulated high amount of GD3 might be the main factor for the dramatic increase of 9-O-acetyl GD3. The ability to acetylate exogenously added GD3 in the normal mouse astrocytes was examined, showing that the wild-type brain might be able to synthesize very low levels of 9-O-acetyl GD3. Increased 9-O-acetyl GD3, in addition to GM3 and GD3, may play an important role in the compensation for deleted complex gangliosides in the mutant mice.
Collapse
Affiliation(s)
- Keiko Furukawa
- Department of Biochemistry II, Nagoya University Graduate School of MedicineNagoya, Japan
- Department of Biomedical Science, College of Life and Health Science, Chubu University, KasugaiAichi, Japan
| | - Wei Aixinjueluo
- Department of Biochemistry II, Nagoya University Graduate School of MedicineNagoya, Japan
| | - Takeshi Kasama
- Instrumental Analysis Research Center for Life Science, Tokyo Medical and Dental UniversityTokyo, Japan
| | - Yuki Ohkawa
- Department of Biochemistry II, Nagoya University Graduate School of MedicineNagoya, Japan
| | - Michiko Yoshihara
- Department of Biochemistry II, Nagoya University Graduate School of MedicineNagoya, Japan
| | - Yusuke Ohmi
- Department of Biochemistry II, Nagoya University Graduate School of MedicineNagoya, Japan
| | - Orie Tajima
- Department of Biochemistry II, Nagoya University Graduate School of MedicineNagoya, Japan
- Department of Biomedical Science, College of Life and Health Science, Chubu University, KasugaiAichi, Japan
| | - Akio Suzumura
- Department of Immune System, Institute for Environmental MedicineNagoya, Japan
| | - Daiji Kittaka
- Department of Biochemistry II, Nagoya University Graduate School of MedicineNagoya, Japan
| | - Koichi Furukawa
- Department of Biochemistry II, Nagoya University Graduate School of MedicineNagoya, Japan
| |
Collapse
|
16
|
Yu YP, Cheng MC, Wu SH. High-performance CE: an effective method to study lactonization of alpha2,8-linked oligosialic acid. Electrophoresis 2006; 27:4487-99. [PMID: 17054086 DOI: 10.1002/elps.200600080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A sensitive and efficient method using high-performance CE (HPCE) and neuraminidase hydrolysis was developed to study the lactonization and hydrolysis of alpha2,8-pentasialic acid. Eleven lactone species of pentasialic acid formed in glacial acetic acid were detected and classified into three groups based on the number of carboxylic acids: monolactones with four carboxylic acids, dilactones with three carboxylic acids, and trilactones with two carboxylic acids. These lactones eluted between the original pentamer (with five carboxylic acids) and the fully lactonized species (with one carboxylic acid) in HPCE. Eight of the isomers were identified by hydrolysis with neuraminodase. Results obtained from previous reports and from this study together reveal a general rule for predicting the subtle difference in the acidity of each carboxylic acid in oligosialic acids: the closer the carboxylic acid is to the nonreducing end, the more acidic it is. Therefore, the elution order of lactone isomers having the same number of carboxylic groups can be predicted from the position of the free carboxylic groups in pentasialic acid. We used this principle and the results of hydrolysis with neuraminidase to identify hexamer lactone isomers separated by HPCE.
Collapse
Affiliation(s)
- Yi-Ping Yu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | | | | |
Collapse
|
17
|
Houliston RS, Endtz HP, Yuki N, Li J, Jarrell HC, Koga M, van Belkum A, Karwaski MF, Wakarchuk WW, Gilbert M. Identification of a sialate O-acetyltransferase from Campylobacter jejuni: demonstration of direct transfer to the C-9 position of terminalalpha-2, 8-linked sialic acid. J Biol Chem 2006; 281:11480-6. [PMID: 16481326 DOI: 10.1074/jbc.m512183200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have identified a sialate O-acetyltransferase in the lipo-oligosaccharide biosynthesis locus of Campylobacter jejuni. Strains possessing this locus are known to produce sialylated outer core structures that mimic host gangliosides, and have been implicated in triggering the onset of Guillain-Barré syndrome. The acetyltransferase, which was cloned and expressed as a fusion construct in Escherichia coli, is soluble and homologous with members of the NodL-LacA-CysE family of O-acetyltransferases. This enzyme catalyzes the transfer of O-acetyl groups onto oligosaccharide-bound sialic acid, with a high specificity for terminal alpha2,8-linked residues. The modification is directed to C-9 and not C-7 as is believed to occur more commonly in other organisms. Despite their wide prevalence and importance in both eukaryotes and prokaryotes, this is the first report to describe the characterization of a purified sialate O-acetyltransferase.
Collapse
Affiliation(s)
- R Scott Houliston
- Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Schauer R. Sialic acids: fascinating sugars in higher animals and man. ZOOLOGY 2006; 107:49-64. [PMID: 16351927 DOI: 10.1016/j.zool.2003.10.002] [Citation(s) in RCA: 315] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2003] [Accepted: 10/13/2003] [Indexed: 01/29/2023]
Abstract
Sialic acids are acidic monosaccharides, which are among the most important molecules of higher animals, and occur in some microorganisms. They are bound to complex carbohydrates and occupy prominent positions, especially in cell membranes. Their structural diversity is high and, correspondingly, the mechanisms for their biosynthesis are complex. Sialic acid substituents strongly influence the activity of catabolic enzymes, in particular the sialidases, and thus the turnover rate of glycoconjugates. These sugars are involved in manifold cell functions. Due to the surface location of the acidic molecules they shield macromolecules and cells from enzymatic and immunological attacks. But they also represent recognition sites for various physiological receptors as well as for toxins and microorganisms, and thus allow their colonization. Many viruses use sialic acids for the infection of cells. As sialic acids also play a decisive role in tumor biology they prove to be rather versatile molecules that modulate cell biological events in a sensitive way. It is discussed that their evolvement may have stimulated evolution and rendered organisms less vulnerable to environmental attacks. However, disturbance of their metabolism may cause diseases.
Collapse
Affiliation(s)
- Roland Schauer
- Biochemical Institute, University of Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany.
| |
Collapse
|
19
|
Kniep B, Kniep E, Ozkucur N, Barz S, Bachmann M, Malisan F, Testi R, Rieber EP. 9-O-acetyl GD3 protects tumor cells from apoptosis. Int J Cancer 2006; 119:67-73. [PMID: 16432837 DOI: 10.1002/ijc.21788] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ganglioside GD3 (Neu5Ac alpha8Neu5Ac alpha3Gal beta4GlcCer) is an intracellular lipid messenger that induces apoptosis by targeting mitochondria in various cell types. GD3 can also promote apoptosis when externally added to cells. Previous studies showed that the proapoptotic effects of GD3 can be counteracted by 9-O-acetylation. To determine whether 9-O-acetyl GD3 (acGD3) has a general antiapoptotic potential, the apoptosis-sensitive Jurkat cell line and an apoptosis-sensitive variant of the cell line Molt-4 were preincubated with micromolar concentrations of acGD3 and then treated with inducers of apoptosis. A reduced apoptotic index and an increased cell viability were observed. On the other hand, when the Jurkat cells were treated with GD3 for extended periods of time, a population was selected that was resistant to apoptosis induction by N-acetyl sphingosine as well as by the anti-leukemic drug daunorubicin. Comparative analysis of gangliosides revealed the formation of acGD3 in the resistant Jurkat cells that was not found in the apoptosis-sensitive cells. Conversely, exposing the acGD3 positive and apoptosis-resistant cell line Molt-4 to the O-deacetylating activity of salicylate resulted in a complete disappearance of acGD3 and an enhanced sensitivity to N-acetyl sphingosine-mediated apoptosis. Formation of acGD3 might thus represent a new mechanism how tumor cells can escape apoptosis.
Collapse
Affiliation(s)
- Bernhard Kniep
- Institute of Immunology, Technical University of Dresden, Dresden, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Ghosh S, Bandyopadhyay S, Bhattacharya DK, Mandal C. Altered erythrocyte membrane characteristics during anemia in childhood acute lymphoblastic leukemia. Ann Hematol 2004; 84:76-84. [PMID: 15338196 DOI: 10.1007/s00277-004-0933-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Accepted: 07/23/2004] [Indexed: 10/26/2022]
Abstract
Anemia is a prominent feature in children with acute lymphoblastic leukemia (ALL). To investigate the erythrocyte features during anemia in these patients, we studied the altered characters of these cells and oxidative stress imposed in their serum. This investigation reveals that erythrocytes from ALL patients show (1) increased membrane fluidity detected by fluorescence anisotropy studies, increased osmotic fragility detected by hemolysis of erythrocytes in different saline concentrations, and increased hydrophobicity as measured by binding with 8-anilino-1-naphthalenesulfonic acid, (2) enhanced (approximately threefold) glycosylation and sialylation, monitored by digoxigenin enzyme assay, and (3) expression of disease-specific 210, 105, 83, 54, and 28 kDa 9-O-acetyl sialoglycoconjugates (9-O-AcSGs) demonstrated by Western blot analysis and fluorescence-activated cell sorter (FACS) analysis studies using Achatinin-H with specificity towards 9-O-AcSAalpha2-6GalNAc as the analytical probe. (4) In addition, induced oxidative stress was observed in the sera of these children as indicated by increased nitric oxide (approximately fourfold) and thiobarbituric acid (TBA) reactive species (twofold) as detected by Griess reaction and TBA assay, respectively. For all the experiments, erythrocytes from normal individuals served as controls. Thus, the altered membrane characteristics together with their exposure to induced oxidative stress in serum are found to be a few features restricted to diseased erythrocytes. Taken together, our results are suggestive of their interplay in the contribution to the observed anemia in these patients, which may be exploited for better management of the disease.
Collapse
Affiliation(s)
- Shyamasree Ghosh
- Immunobiology Division, Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, Kolkata, 700032, India
| | | | | | | |
Collapse
|
21
|
Schauer R. Victor Ginsburg's influence on my research of the role of sialic acids in biological recognition. Arch Biochem Biophys 2004; 426:132-41. [PMID: 15158663 DOI: 10.1016/j.abb.2004.03.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 02/27/2004] [Indexed: 12/11/2022]
Abstract
Sialic acids are monosaccharides with relatively strong acidity which belong to the most important molecules of higher animals and also occur in some microorganisms. They are bound to complex carbohydrates and occupy prominent positions, especially in cell membranes. Their structural diversity is high and, correspondingly, the mechanisms for their biosynthesis complex. Sialic acids are involved in a great number of cell functions. Due to their cell surface location these acidic molecules shield macromolecules and cells from enzymatic and immunological attacks and thus contribute to innate immunity. In contrast to this masking role, enabling, for example, blood cells and serum glycoproteins a longer life-time, sialic acids also represent recognition sites for various physiological receptors, such as the selectins and siglecs, as well as for toxins and microorganisms and thus allow their colonization. The recognition function of sialic acids can again be masked by O-acetylation, which modifies the interaction with receptors. Many viruses use sialic acids for the infection of cells. As sialic acids play also a decisive role in tumor biology, they prove to be rather versatile molecules that modulate biological and pathological cellular events in a sensitive way. Thus, they are most prominent representatives of mediators of molecular and cellular recognition.
Collapse
Affiliation(s)
- Roland Schauer
- Biochemisches Institut, Christian-Albrechts-Universität, Olshausenstrasse 40, Kiel D-24098, Germany.
| |
Collapse
|
22
|
Shen Y, Kohla G, Lrhorfi AL, Sipos B, Kalthoff H, Gerwig GJ, Kamerling JP, Schauer R, Tiralongo J. O-acetylation and de-O-acetylation of sialic acids in human colorectal carcinoma. ACTA ACUST UNITED AC 2004; 271:281-90. [PMID: 14717696 DOI: 10.1046/j.1432-1033.2003.03927.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A decrease in the level of O-acetylated sialic acids observed in colorectal carcinoma may lead to an increase in the expression of sialyl Lewis(X), a tumor-associated antigen, which is related to progression of colorectal cancer to metastasis. The underlying mechanism for this reduction is, however, not fully understood. Two enzymes are thought to be primarily responsible for the turnover of O-acetyl ester groups on sialic acids; sialate-O-acetyltransferase (OAT) and sialate-O-acetylesterase (OAE). We have previously reported the characterization of OAT activity from normal colon mucosa, which efficiently O-acetylates CMP-Neu5Ac exclusively in the Golgi apparatus prior to the action of sialyltransferase. In this report we describe the identification of a lysosomal and a cytosolic OAE activity in human colonic mucosa that specifically hydrolyses 9-O-acetyl groups on sialic acid. Utilizing matched resection margin and cancer tissue from colorectal carcinoma patients we provide strong evidence suggesting that the level of O-acetylated sialic acids present in normal and diseased human colon may be dependent on the relative activities of OAT to lysosomal OAE. Furthermore, we show that the level of free cytosolic Neu5,9Ac2 in human colon is regulated by the relative activity of the cytosolic OAE.
Collapse
Affiliation(s)
- Yanqin Shen
- Biochemisches Institut, Christian-Albrechts-Universität zu Kiel, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Iwersen M, Dora H, Kohla G, Gasa S, Schauer R. Solubilisation and properties of the sialate-4-O-acetyltransferase from guinea pig liver. Biol Chem 2003; 384:1035-47. [PMID: 12956420 DOI: 10.1515/bc.2003.116] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The O-acetylation of sialic acids turns out to be one of the most important modifications that influence the diverse biological and pathophysiological properties of glycoconjugates in animals and microorganisms. To understand the functions of this esterification, knowledge of the properties, structures and regulation of expression of the enzymes involved is essential. Attempts to solubilise, purify or clone the gene of one of the sialate-O-acetyltransferases have failed so far. Here we report on the solubilisation of the sialate-4-O-acetyltransferase from guinea pig liver, the first and essential step in the purification and molecular characterisation of this enzyme, by the zwitterionic detergent CHAPS. This enzyme O-acetylates sialic acids at C-4 both free and bound to oligosaccharides, glycoproteins and glycolipids with varying activity, however, gangliosides proved to be the best substrates. Correspondingly, a rapid enzyme test was elaborated using the ganglioside GD3. The soluble O-acetyltransferase maximally operated at 30 degrees C, pH 5.6, and 50-70 mM KCl and K2HPO4 concentrations. The Km values were 3.6 microM for AcCoA and 1.2 microM for GD3. CoA inhibits the enzyme with a Ki value of 14.8 microM. A most important discovery enabling further enzyme purification is its need for an unknown low molecular mass and heat-stable cofactor that can be separated from the crude enzyme preparation by 30 kDa ultrafiltration.
Collapse
Affiliation(s)
- Matthias Iwersen
- Biochemisches Institut, Christian-Albrechts-Universität, Olshausenstr. 40, D-24098 Kiel, Germany
| | | | | | | | | |
Collapse
|
24
|
Satake H, Chen HY, Varki A. Genes modulated by expression of GD3 synthase in Chinese hamster ovary cells. Evidence that the Tis21 gene is involved in the induction of GD3 9-O-acetylation. J Biol Chem 2003; 278:7942-8. [PMID: 12493756 DOI: 10.1074/jbc.m210565200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
9-O-Acetylation is a common sialic acid modification, expressed in a developmentally regulated and tissue/cell type-specific manner. The relevant 9-O-acetyltransferase(s) have not been isolated or cloned; nor have mechanisms for their regulation been elucidated. We previously showed that transfection of the GD3 synthase (ST8Sia-I) gene into Chinese hamster ovary (CHO)-K1 cells gave expression of not only the disialoganglioside GD3 but also 9-O-acetyl-GD3. We now use differential display PCR between wild type CHO-K1 cells and clones stably expressing GD3 synthase (CHO-GD3 cells) to detect any increased expression of other genes and explore the possible induction of a 9-O-acetyltransferase. The four CHO mRNAs showing major up-regulation were homologous to VCAM-1, Tis21, the KC-protein-like protein, and a functionally unknown type II transmembrane protein. A moderate increase in expression of the FxC1 and SPR-1 genes was also seen. Interestingly, these are different from genes observed by others to be up-regulated after transfection of GD3 synthase into a neuroblastoma cell line. We also isolated a CHO-GD3 mutant lacking 9-O-acetyl-GD3 following chemical mutagenesis (CHO-GD3-OAc(-)). Analysis of the above differential display PCR-derived genes in these cells showed that expression of Tis21 was selectively reduced. Transfection of a mouse Tis21 cDNA into the CHO-GD3-OAc(-) mutant cells restored 9-O-acetyl-GD3 expression. Since the only major gangliosides expressed by CHO-GD3 cells are GD3 and 9-O-acetyl-GD3 (in addition to GM3, the predominant ganglioside type in wild-type CHO-K1 cells), we conclude that GD3 enhances its own 9-O-acetylation via induction of Tis21. This is the first known nuclear inducible factor for 9-O-acetylation and also the first proof that 9-O-acetylation can be directly regulated by GD3 synthase. Finally, transfection of CHO-GD3-OAc(-) mutant cells with ST6Gal-I induced 9-O-acetylation specifically on sialylated N-glycans, in a manner similar to wild-type cells. This indicates separate machineries for 9-O-acetylation on alpha2-8-linked sialic acids of gangliosides and on alpha2-6-linked sialic acids on N-glycans.
Collapse
Affiliation(s)
- Honoo Satake
- Glycobiology Research and Training Center, Department of Medicine, University of California, San Diego, La Jolla 92093-0687, USA
| | | | | |
Collapse
|
25
|
Abstract
Neuroectodermic tumors can mostly be characterized by the presence of tumor-associated glycosphingolipid antigens, such as gangliosides, defined by monoclonal antibodies. Recently, cumulative evidence indicates that gangliosides modify the biological effects of several trophic factors, in vitro and in vivo, as well as the mitogenic signaling cascade that these factors generate. The functional roles of gangliosides in tumor progression can be revisited: (i) ganglioside antigens on the cell surface, or shed from the cells, act as immunosuppressors, as typically observed for the suppression of cytotoxic T cells and dendritic cells, (ii) certain gangliosides, such as GD3 or GM2, promote tumor-associated angiogenesis, (iii) gangliosides strongly regulate cell adhesion/motility and thus initiate tumor metastasis, (iv) ganglioside antigens are directly connected with transducer molecules in microdomains to initiate adhesion coupled with signaling, and (v) ganglioside antigens and their catabolites are modulators of signal transduction through interaction with tyrosine kinases associated with growth factor receptors or other protein kinases. Given the potential importance of these sialylated gangliosides and their modulating biological behavior in vivo, further studies on the role of gangliosides are warranted.
Collapse
Affiliation(s)
- S Birklé
- Ecole Nationale Vétérinaire, Nantes, France
| | | | | | | | | |
Collapse
|
26
|
Martin LT, Verhagen A, Varki A. Recombinant influenza C hemagglutinin-esterase as a probe for sialic acid 9-O-acetylation. Methods Enzymol 2003; 363:489-98. [PMID: 14579598 DOI: 10.1016/s0076-6879(03)01074-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Laura T Martin
- Departments of Medicine and Cellular Molecular Medicine, University of California-San Diego, School of Medicine, La Jolla, California 92093, USA
| | | | | |
Collapse
|
27
|
Martin LT, Marth JD, Varki A, Varki NM. Genetically altered mice with different sialyltransferase deficiencies show tissue-specific alterations in sialylation and sialic acid 9-O-acetylation. J Biol Chem 2002; 277:32930-8. [PMID: 12068010 DOI: 10.1074/jbc.m203362200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycan chains on glycoconjugates traversing the Golgi apparatus are often terminated by sialic acid residues, which can also be 9-O-acetylated. This process involves competition between multiple Golgi enzymes. Expression levels of Golgi enzyme mRNAs do not always correlate with enzyme activity, which in turn cannot accurately predict glycan sequences found on cell surfaces. Here we examine the cell type-specific expression of terminal glycans in tissues of normal mice in comparison with animals deficient in ST6Gal-I (transfers alpha2-6-linked sialic acid to Galbeta1-4GlcNAc) or ST3Gal-I (transfers alpha2-3-linked sialic acid to Galbeta1-3GalNAc). Tissues of ST6Gal-I null mice showed minimal binding of an alpha2-6-sialic acid-specific lectin, indicating that no other enzyme generates Siaalpha2-6Galbeta1-4GlcNAc and that Siaalpha2-6GalNAc (sialyl-Tn) is rare in mice. However, exposed Galbeta1-4GlcNAc termini were only moderately increased, indicating that these can be partially capped by other enzymes. Indeed, Galalpha1-3Galbeta1-4GlcNAc and Fucalpha1-2Galbeta1-4GlcNAc termini were enhanced in some tissues. Many tissues of ST3Gal-I null animals showed increases in Galbeta1-3GalNAc termini, and some increases in poly-N-acetyllactosamines. However, overall expression of alpha2-3-linked sialic acid was selectively reduced only in a few instances, indicating that other ST3Gal enzymes can generate this linkage in most tissues. Highly selective losses of 9-O-acetylation of sialic acid residues were also observed, with ST6Gal-I deficiency causing loss on endothelium and ST3Gal-I deficiency giving a marked decrease on CD4(+) lymphocytes. These data demonstrate selective regulation of sialylation and 9-O-acetylation, point to cell types with potential physiological defects in null animals, and show in vivo evidence for competition between Golgi enzymes.
Collapse
Affiliation(s)
- Laura T Martin
- Glycobiology Research and Training Center, Department of Medicine, University of California San Diego, La Jolla, California 92093, USA
| | | | | | | |
Collapse
|
28
|
Shen Y, Tiralongo J, Iwersen M, Sipos B, Kalthoff H, Schauer R. Characterization of the sialate-7(9)-O-acetyltransferase from the microsomes of human colonic mucosa. Biol Chem 2002; 383:307-17. [PMID: 11934269 DOI: 10.1515/bc.2002.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sialic acids present on human colonic mucins are highly O-acetylated, however, little is known about the underlying enzymatic activity required for O-acetylation in this tissue. Here we report on the substrate specificity, subcellular localization and characterization of the sialate-7(9)-O-acetyltransferase in normal human colonic mucosa. Using CMP-Neu5Ac, the most efficient acceptor substrate of all those tested, the enzymatic activity was found to be optimal at 37 degrees C, with a pH optimum of 7.0. Activity was also found to be dependent on protein, CMP-Neu5Ac (Km: 59.2 microM) and AcCoA (Km: 6.1 microM) concentrations, as well as membrane integrity. The enzyme's activity could be inhibited by CoA with a Ki of 11.9 microM. In addition, enzymatic activity was found to be localized in the Golgi-enriched membrane fraction. The nature of the O-acetylated products formed were verified with the aid of chromatographic and enzymatic techniques. The main product was 9-O-acetylated Neu5Ac, with a significant amount of oligo-O-acetylated Neu5Ac also being detected. The utilization of CMP-Neu5Ac as the acceptor substrate was confirmed by the isolation and characterization of the putative product, CMP-Neu5,9Ac2, using ion-exchange chromatography. The ability of CMP-Neu5,9Ac2 to act as a sialic acid donor for sialyltransferases represents the conclusive demonstration for the formation of CMP-Neu5,9Ac2.
Collapse
Affiliation(s)
- Yanqin Shen
- Biochemisches Institut, Christian-Albrechts-Universität zu Kiel, Germany
| | | | | | | | | | | |
Collapse
|
29
|
Schauer R, Schmid H, Pommerencke J, Iwersen M, Kohla G. Metabolism and role of O-acetylated sialic acids. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2001; 491:325-42. [PMID: 14533806 DOI: 10.1007/978-1-4615-1267-7_21] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- R Schauer
- Biochemisches Institut, Christian-Albrechts-Universität Olshausenstrasse 40, D-24098 Kiel, Germany.
| | | | | | | | | |
Collapse
|
30
|
Tiralongo J, Schmid H, Thun R, Iwersen M, Schauer R. Characterisation of the enzymatic 4-O-acetylation of sialic acids in microsomes from equine submandibular glands. Glycoconj J 2000; 17:849-58. [PMID: 11511809 DOI: 10.1023/a:1010965128335] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Microsomes prepared from equine submandibular glands and incubated with tritium-labelled AcCoA incorporated acid-insoluble radioactivity in a manner dependent on time, protein, membrane integrity and AcCoA concentration, with incorporation being optimal at 37 degrees C and pH 6.6. Under the experimental conditions used a K(M) of 32.1 microM for AcCoA and a V(max) of 1.2 pmol/mg protein x min was obtained. The incorporation of acid-insoluble radioactivity was also inhibited by CoA in a competitive manner (K(i)=240 microM), as well as by para-chloromercuribenzoate, 3'-dephospho-CoA, 5'-IDP, 5'-ADP, beta-NAD and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate. We demonstrate here that this incorporation of radioactivity into endogenous sialic acid is due to the action of an AcCoA:sialate-4-O-acetyltransferase [EC 2.3.1.44]. Radio thin-layer chromatography analyses of propionic acid-released sialic acids showed that the incorporation of radioactivity correlated with the formation of a radiolabelled species that co-migrated with authentic Neu4,5Ac2. Saponification experiments using NaOH, mouse hepatitis virus strain S and Influenza C/JJ/50 virus also showed that the transfer of [3H]acetyl groups from [3H]AcCoA to endogenous sialic acid acceptors was occurring exclusively at carbon 4 of the pyranose ring.
Collapse
Affiliation(s)
- J Tiralongo
- Biochemisches Institut, Christian-Albrechts-Universität, Olshausenstr. 40, D-24098 Kiel, Germany
| | | | | | | | | |
Collapse
|
31
|
Abstract
Slalic acids are one of the most important molecules of life, since they occupy the terminal position on macromolecules and cell membranes and are involved in many biological and pathological phenomena. The structures of sialic acids, comprising a family of over 40 neuraminic acid derivatives, have been elucidated. However, many aspects of the regulation of their metabolism at the enzyme and gene levels, as well as of their functions remain mysterious. Sialic acids play a dual role, not only are they indispensable for the protection to and adaptation of life, but are also utilised by life-threatening infectious microorganisms. In this article the present state of knowledge in sialobiology, with an emphasis on my personal experience in this research area, is outlined including a discussion of necessary future work in this fascinating field of cell biology.
Collapse
Affiliation(s)
- R Schauer
- Biochemisches Institut, Christian-Albrechts-Universität, Kiel, Germany.
| |
Collapse
|
32
|
Birklé S, Gao L, Zeng G, Yu RK. Down-regulation of GD3 ganglioside and its O-acetylated derivative by stable transfection with antisense vector against GD3-synthase gene expression in hamster melanoma cells: effects on cellular growth, melanogenesis, and dendricity. J Neurochem 2000; 74:547-54. [PMID: 10646505 DOI: 10.1046/j.1471-4159.2000.740547.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The expression of gangliosides in hamster melanoma cells is closely related to cellular growth and degree of differentiation, with slow-growing, highly differentiated melanotic melanoma cells expressing GM3 and fast-growing, undifferentiated amelanotic Ab melanoma cells having a preponderance of GD3 and O-acetyl-GD3. We recently showed that down-regulation of O-acetyl-GD3 expression in hamster melanoma cells by introducing the influenza C virus O-acetylesterase cDNA into the cells resulted in induction of dendricity, with a concomitant increased expression of GD3. To examine the effect of the increased GD3 expression in the plasma membrane on the dendricity of the AbC-1 cells, we first established the cDNA coding for hamster GD3-synthase. We then targeted the sialyltransferase gene expression by the antisense knockdown experiment, and the results showed that inhibition of the expression of gangliosides GD3 and O-acetyl-GD3 induced dendricity in the hamster melanoma AbC-1 cell line. These GD3- and O-acetyl-GD3-depleted cells also demonstrated a decreased rate of cell growth, but their melanogenic potential was not affected. These results rule out the possibility that GD3 may serve as an active molecule for dendrite outgrowth in this cell line and suggest that the enhanced expression of O-acetyl-GD3 ganglioside may stimulate cellular growth and suppress certain differentiated phenotypes such as dendrite formation, but not melanogenesis, in our system.
Collapse
Affiliation(s)
- S Birklé
- Department of Biochemistry and Molecular Biophysics, Medical College of Virginia Campus of Virginia Commonwealth University, Richmond 23298-0614, USA
| | | | | | | |
Collapse
|
33
|
Abstract
Glycoproteins with O-glycosidically linked carbohydrate chains of complex structures and functions are found in secretions and on the cell surfaces of cancer cells. The structures of O-glycans are often unusual or abnormal in cancer, and greatly contribute to the phenotype and biology of cancer cells. Some of the mechanisms of changes in O-glycosylation pathways have been determined in cancer model systems. However, O-glycan biosynthesis is a complex process that is still poorly understood. The glycosyltransferases and sulfotransferases that synthesize O-glycans appear to exist as families of related enzymes of which individual members are expressed in a tissue- and growth-specific fashion. Studies of their regulation in cancer may reveal the connection between cancerous transformation and glycosylation which may help to understand and control the abnormal biology of tumor cells. Cancer diagnosis may be based on the appearance of certain glycosylated epitopes, and therapeutic avenues have been designed to attack cancer cells via their glycans.
Collapse
Affiliation(s)
- I Brockhausen
- Department of Biochemistry, University of Toronto, Oncology Research, Toronto Hospital, 67 College Street, Toronto, Ont., Canada.
| |
Collapse
|
34
|
Zhang Y, Lee YC. Acid-catalyzed lactonization of alpha2,8-linked oligo/polysialic acids studied by high performance anion-exchange chromatography. J Biol Chem 1999; 274:6183-9. [PMID: 10037703 DOI: 10.1074/jbc.274.10.6183] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent studies from many laboratories revealed remarkable structural, distributional, and functional diversities of oligo/polysialic acids (OSA/PSA) that exist in organisms ranging from bacteria to man. These diversities are further complicated by the fact that OSA/PSA spontaneously form lactones under even mildly acidic conditions. By using high performance anion-exchange chromatography (HPAEC) with nitrate eluents, we found that lactonization of alpha2,8-linked OSA/PSA (oligo/poly-Neu5Ac, oligo/poly-Neu5Gc and oligo/poly-KDN) proceeds readily, and the lactonization process displays three discrete stages. The initial stage is characterized by limited lactonization occurring between two internal sialic acid residues, reflected by a regular pattern of lactone peaks interdigitated with non-lactonized peaks on HPAEC. In the middle stage, multiple lactonized species are formed from a molecule with a given degree of polymerization (DP), in which the maximum number of lactone rings formed equals DP minus 2. At the final stage, completely lactonized species become the major components, resulting in drastic changes in the physicochemical properties of the sample. Interestingly, the smallest lactonizable OSA are tetramer, trimer, and dimer at the initial, middle, and final stages, respectively. At any of the stages, OSA/PSA of higher DP lactonize more rapidly, but all the lactone rings rapidly open up when exposed to mild alkali. Lactonized OSA/PSA are resistant to both enzyme- and acid-catalyzed glycosidic bond cleavage. The latter fact was utilized to obtain more high DP oligo/poly(alpha2,8-Neu5Gc) chains from a polysialoglycoprotein. Our results should be useful in preparation, storage, and analysis of OSA/PSA. Possible biological significance and bioengineering potentials of lactonization are discussed.
Collapse
Affiliation(s)
- Y Zhang
- Biology Department, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | | |
Collapse
|
35
|
Iwersen M, Vandamme-Feldhaus V, Schauer R. Enzymatic 4-O-acetylation of N-acetylneuraminic acid in guinea-pig liver. Glycoconj J 1998; 15:895-904. [PMID: 10052593 DOI: 10.1023/a:1006911100081] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Sialic acids from the liver and serum of guinea-pig are composed of N-acetylneuraminic acid (Neu5Ac; 85% and 61%, respectively), N-acetyl-4-O-acetylneuraminic acid (Neu4,5Ac2; 10% and 32%, respectively) and N-glycolylneuraminic acid (Neu5Gc; 5% and 7%, respectively), besides traces of N-glycolyl-4-O-acetylneuraminic acid in serum. The analysis was carried out using thin-layer chromatography, high-performance liquid chromatography, electron impact ionization mass spectrometry, and different enzymes (sialidase, sialate esterase, and sialate-pyruvate lyase after hydrolysis and purification of the sialic acids by ion-exchange chromatography). We showed that this O-acetylation of sialic acids is due to the activity of an acetyl-coenzyme A:sialate-4-O-acetyltransferase (EC 2.3.1.44), which occurs together with sialyltransferase activity in Golgi-enriched membrane fractions of guinea-pig liver. The enzyme operates optimally at 30 degrees C in 70 mM potassium phosphate buffer at pH 6.7 and in the presence of 90 mM KCI with an apparent KM for AcCoA of 0.6 1microM and a Vmax of 20 pmol/mg protein x min. The enzyme is inhibited by coenzyme A in a mixed-competitive manner (Ki = 4.2 microM), as well as by parachloromercuribenzoate, MnCl2, saponin and Triton X-100.
Collapse
Affiliation(s)
- M Iwersen
- Biochemisches Institut, Christian-Albrechts-Universität, Kiel, Germany
| | | | | |
Collapse
|
36
|
Abstract
Sialic acids can be acetylated at the 4, 7, 8 and/or 9 position. Biological roles of these substitutions have been missed until recently because of their low abundance and lability to conventional purification methods. The recent advances in the analysis of sialic acids have allowed to demonstrate that O-acetylation has a selective but widespread distribution. The metabolism of acetylated sialic acids is under the control of two groups of enzymes, O-acetyl transferases and 9-O-acetyl esterases. O-acetyl transferases are difficult to purify, and furthermore, attempts at expression cloning have failed in isolating the true 9-O-acetyl transferase cDNA. This explains that the regulation of the selective expression of O-acetylated sialic acid in not completely understood. Acetylation of sialic acid is expressed on the outer most part of the carbohydrate moiety of membrane and secreted glycoconjugates. This particular location explains why this modification is involved in cell/cell interactions and in the non-immune protection of mucosa.
Collapse
Affiliation(s)
- A Klein
- Unité INSERM 377, Lille, France
| | | |
Collapse
|