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Haltom AR, Jafar-Nejad H. The multiple roles of epidermal growth factor repeat O-glycans in animal development. Glycobiology 2015; 25:1027-42. [PMID: 26175457 DOI: 10.1093/glycob/cwv052] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 07/08/2015] [Indexed: 12/26/2022] Open
Abstract
The epidermal growth factor (EGF)-like repeat is a common, evolutionarily conserved motif found in secreted proteins and the extracellular domain of transmembrane proteins. EGF repeats harbor six cysteine residues which form three disulfide bonds and help generate the three-dimensional structure of the EGF repeat. A subset of EGF repeats harbor consensus sequences for the addition of one or more specific O-glycans, which are initiated by O-glucose, O-fucose or O-N-acetylglucosamine. These glycans are relatively rare compared to mucin-type O-glycans. However, genetic experiments in model organisms and cell-based assays indicate that at least some of the glycosyltransferases involved in the addition of O-glycans to EGF repeats play important roles in animal development. These studies, combined with state-of-the-art biochemical and structural biology experiments have started to provide an in-depth picture of how these glycans regulate the function of the proteins to which they are linked. In this review, we will discuss the biological roles assigned to EGF repeat O-glycans and the corresponding glycosyltransferases. Since Notch receptors are the best studied proteins with biologically-relevant O-glycans on EGF repeats, a significant part of this review is devoted to the role of these glycans in the regulation of the Notch signaling pathway. We also discuss recently identified proteins other than Notch which depend on EGF repeat glycans to function properly. Several glycosyltransferases involved in the addition or elongation of O-glycans on EGF repeats are mutated in human diseases. Therefore, mechanistic understanding of the functional roles of these carbohydrate modifications is of interest from both basic science and translational perspectives.
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Affiliation(s)
- Amanda R Haltom
- Program in Genes and Development, The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA Department of Molecular and Human Genetics
| | - Hamed Jafar-Nejad
- Department of Molecular and Human Genetics Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
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52
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Abstract
N-Glycosylation has long been linked to protein folding and quality control in the endoplasmic reticulum (ER). Recent work has shown that O-linked glycosylation and the corresponding glycosyltransferases also participate in this important function. Notably, Protein O-fucosyltransferase 1 (Ofut1/Pofut1), a soluble, ER localized enzyme that fucosylates Epidermal Growth Factor-like (EGF) repeats, functions as a chaperone involved in the proper localization of the Notch receptor in certain contexts. Pofut2, a related enzyme that modifies Thrombospondin type I repeats (TSRs), has also been hypothesized to play a role in the folding and quality control of TSR-containing proteins. Both enzymes only modify fully folded substrates suggesting that they are able to distinguish between folded and unfolded structures. Pofuts have known physiological relevance and are conserved across metazoans. Though consensus sequences for O-fucosylation have been established and structures of both Pofuts have been studied, the mechanism of how they participate in protein folding is not known. This article discusses past and recent advances made in novel roles for these protein O-glycosyltransferases.
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Affiliation(s)
- Deepika Vasudevan
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, 11794-5215, USA
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53
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Wang W, Yu S, Zimmerman G, Wang Y, Myers J, Yu VWC, Huang D, Huang X, Shim J, Huang Y, Xin W, Qiao P, Yan M, Xin W, Scadden DT, Stanley P, Lowe JB, Huang AY, Siebel CW, Zhou L. Notch Receptor-Ligand Engagement Maintains Hematopoietic Stem Cell Quiescence and Niche Retention. Stem Cells 2015; 33:2280-93. [PMID: 25851125 DOI: 10.1002/stem.2031] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 03/21/2015] [Indexed: 01/05/2023]
Abstract
Notch is long recognized as a signaling molecule important for stem cell self-renewal and fate determination. Here, we reveal a novel adhesive role of Notch-ligand engagement in hematopoietic stem and progenitor cells (HSPCs). Using mice with conditional loss of O-fucosylglycans on Notch EGF-like repeats important for the binding of Notch ligands, we report that HSPCs with faulty ligand binding ability display enhanced cycling accompanied by increased egress from the marrow, a phenotype mainly attributed to their reduced adhesion to Notch ligand-expressing stromal cells and osteoblastic cells and their altered occupation in osteoblastic niches. Adhesion to Notch ligand-bearing osteoblastic or stromal cells inhibits wild type but not O-fucosylglycan-deficient HSPC cycling, independent of RBP-JK -mediated canonical Notch signaling. Furthermore, Notch-ligand neutralizing antibodies induce RBP-JK -independent HSPC egress and enhanced HSPC mobilization. We, therefore, conclude that Notch receptor-ligand engagement controls HSPC quiescence and retention in the marrow niche that is dependent on O-fucosylglycans on Notch.
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Affiliation(s)
- Weihuan Wang
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Shuiliang Yu
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Grant Zimmerman
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yiwei Wang
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Jay Myers
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Vionnie W C Yu
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Dan Huang
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Xiaoran Huang
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Jeongsup Shim
- Department of Pathology, Genentech, Inc., South San Francisco, California, USA
| | - Yuanshuai Huang
- Department of Blood Transfusion, Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan Province, People's Republic of China
| | - William Xin
- University School, Hunting Valley, Ohio, USA
| | - Peter Qiao
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Minhong Yan
- Department of Molecular Biology Oncology, Genentech, Inc., South San Francisco, California, USA
| | - Wei Xin
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - David T Scadden
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Pamela Stanley
- Department of Cell Biology, Albert Einstein College of Medicine, New York, New York, USA
| | - John B Lowe
- Department of Pathology, Genentech, Inc., South San Francisco, California, USA
| | - Alex Y Huang
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Christian W Siebel
- Department of Molecular Biology Oncology, Genentech, Inc., South San Francisco, California, USA
| | - Lan Zhou
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
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54
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Vasudevan D, Takeuchi H, Johar SS, Majerus E, Haltiwanger RS. Peters plus syndrome mutations disrupt a noncanonical ER quality-control mechanism. Curr Biol 2014; 25:286-295. [PMID: 25544610 DOI: 10.1016/j.cub.2014.11.049] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/06/2014] [Accepted: 11/19/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND O-fucose is added to cysteine-rich domains called thrombospondin type 1 repeats (TSRs) by protein O-fucosyltransferase 2 (POFUT2) and is elongated with glucose by β3-glucosyltransferase (B3GLCT). Mutations in B3GLCT result in Peters plus syndrome (PPS), an autosomal recessive disorder characterized by eye and other developmental defects. Although 49 putative targets are known, the function of the disaccharide and its role in PPS remain unexplored. RESULTS Here we show that while POFUT2 is required for secretion of all targets tested, B3GLCT only affects the secretion of a subset, consistent with the observation that B3GLCT mutant phenotypes in PPS patients are less severe than embryonic lethal phenotypes of Pofut2-null mice. O-glycosylation occurs cotranslationally, as TSRs fold. Mass spectral analysis reveals that TSRs from mature, secreted protein are stoichiometrically modified with the disaccharide, whereas TSRs from protein still folding in the ER are partially modified, suggesting that O-glycosylation marks folded TSRs and promotes ER exit. In vitro unfolding assays demonstrate that fucose and glucose stabilize folded TSRs in an additive manner. In vitro refolding assays under redox conditions showed that POFUT2 recognizes, glycosylates, and stabilizes the folded form of TSRs, resulting in a net acceleration of folding. CONCLUSIONS While known ER quality-control machinery rely on identifying and tagging unfolded proteins, we find that POFUT2 and B3GLCT mediate a noncanonical ER quality-control mechanism that recognizes folded TSRs and stabilizes them by glycosylation. Our findings provide a molecular basis for the defects observed in PPS and potential targets that contribute to the pathology.
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Affiliation(s)
- Deepika Vasudevan
- Department of Biochemistry and Cell Biology, 450 Life Sciences Building, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | - Hideyuki Takeuchi
- Department of Biochemistry and Cell Biology, 450 Life Sciences Building, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | - Sumreet Singh Johar
- Department of Biochemistry and Cell Biology, 450 Life Sciences Building, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | - Elaine Majerus
- Department of Internal Medicine, Division of Hematology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Robert S Haltiwanger
- Department of Biochemistry and Cell Biology, 450 Life Sciences Building, Stony Brook University, Stony Brook, NY 11794-5215, USA.
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55
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Protein O-fucosyltransferase 1 expression impacts myogenic C2C12 cell commitment via the Notch signaling pathway. Mol Cell Biol 2014; 35:391-405. [PMID: 25384974 DOI: 10.1128/mcb.00890-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Notch signaling pathway plays a crucial role in skeletal muscle regeneration in mammals by controlling the transition of satellite cells from quiescence to an activated state, their proliferation, and their commitment toward myotubes or self-renewal. O-fucosylation on Notch receptor epidermal growth factor (EGF)-like repeats is catalyzed by the protein O-fucosyltransferase 1 (Pofut1) and primarily controls Notch interaction with its ligands. To approach the role of O-fucosylation in myogenesis, we analyzed a murine myoblastic C2C12 cell line downregulated for Pofut1 expression by short hairpin RNA (shRNA) inhibition during the time course of differentiation. Knockdown of Pofut1 affected the signaling pathway activation by a reduction of the amount of cleaved Notch intracellular domain and a decrease in downstream Notch target gene expression. Depletion in Pax7(+)/MyoD(-) cells and earlier myogenic program entrance were observed, leading to an increase in myotube quantity with a small number of nuclei, reflecting fusion defects. The rescue of Pofut1 expression in knockdown cells restored Notch signaling activation and a normal course in C2C12 differentiation. Our results establish the critical role of Pofut1 on Notch pathway activation during myogenic differentiation.
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56
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Ishio A, Sasamura T, Ayukawa T, Kuroda J, Ishikawa HO, Aoyama N, Matsumoto K, Gushiken T, Okajima T, Yamakawa T, Matsuno K. O-fucose monosaccharide of Drosophila Notch has a temperature-sensitive function and cooperates with O-glucose glycan in Notch transport and Notch signaling activation. J Biol Chem 2014; 290:505-19. [PMID: 25378397 DOI: 10.1074/jbc.m114.616847] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Notch (N) is a transmembrane receptor that mediates the cell-cell interactions necessary for many cell fate decisions. N has many epidermal growth factor-like repeats that are O-fucosylated by the protein O-fucosyltransferase 1 (O-Fut1), and the O-fut1 gene is essential for N signaling. However, the role of the monosaccharide O-fucose on N is unclear, because O-Fut1 also appears to have O-fucosyltransferase activity-independent functions, including as an N-specific chaperon. Such an enzymatic activity-independent function could account for the essential role of O-fut1 in N signaling. To evaluate the role of the monosaccharide O-fucose modification in N signaling, here we generated a knock-in mutant of O-fut1 (O-fut1(R245A knock-in)), which expresses a mutant protein that lacks O-fucosyltransferase activity but maintains the N-specific chaperon activity. Using O-fut1(R245A knock-in) and other gene mutations that abolish the O-fucosylation of N, we found that the monosaccharide O-fucose modification of N has a temperature-sensitive function that is essential for N signaling. The O-fucose monosaccharide and O-glucose glycan modification, catalyzed by Rumi, function redundantly in the activation of N signaling. We also showed that the redundant function of these two modifications is responsible for the presence of N at the cell surface. Our findings elucidate how different forms of glycosylation on a protein can influence the protein's functions.
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Affiliation(s)
- Akira Ishio
- From the Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-1500, the Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043
| | - Takeshi Sasamura
- the Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043
| | - Tomonori Ayukawa
- From the Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-1500
| | - Junpei Kuroda
- the Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043
| | - Hiroyuki O Ishikawa
- Genome and Drug Research Center, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, the Graduate School of Science,Chiba University, 1-33 Yayoi, Inage, Chiba, and
| | - Naoki Aoyama
- From the Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-1500
| | - Kenjiroo Matsumoto
- the Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043
| | - Takuma Gushiken
- From the Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-1500, the Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043
| | - Tetsuya Okajima
- the Department of Biochemistry II, Nagoya University Graduate School of Medicine, Tsurumai, Showa-ku, Nagoya 466-0065, Japan
| | - Tomoko Yamakawa
- the Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043
| | - Kenji Matsuno
- the Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043,
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57
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Significance of glycosylation in Notch signaling. Biochem Biophys Res Commun 2014; 453:235-42. [PMID: 24909690 DOI: 10.1016/j.bbrc.2014.05.115] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 05/27/2014] [Indexed: 12/15/2022]
Abstract
Notch signaling is essential for cell-fate specification in metazoans, and dysregulation of the pathway leads to a variety of human diseases including heart and vascular defects as well as cancer. Glycosylation of the Notch extracellular domain has emerged as an elegant means for regulating Notch activity, especially since the discovery that Fringe is a glycosyltransferase that modifies O-fucose in 2000. Since then, several other O-glycans on the extracellular domain have been demonstrated to modulate Notch activity. Here we will describe recent results on the molecular mechanisms by which Fringe modulates Notch activity, summarize recent work on how O-glucose, O-GlcNAc, and O-GalNAc glycans affect Notch, and discuss several human genetic disorders resulting from defects in Notch glycosylation.
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58
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Andrawes MB, Xu X, Liu H, Ficarro SB, Marto JA, Aster JC, Blacklow SC. Intrinsic selectivity of Notch 1 for Delta-like 4 over Delta-like 1. J Biol Chem 2013; 288:25477-25489. [PMID: 23839946 DOI: 10.1074/jbc.m113.454850] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Notch signaling makes critical contributions to cell fate determination in all metazoan organisms, yet remarkably little is known about the binding affinity of the four mammalian Notch receptors for their three Delta-like and two Jagged family ligands. Here, we utilized signaling assays and biochemical studies of purified recombinant ligand and receptor molecules to investigate the differences in signaling behavior and intrinsic affinity between Notch1-Dll1 and Notch1-Dll4 complexes. Systematic deletion mutagenesis of the human Notch1 ectodomain revealed that epidermal growth factor (EGF) repeats 6-15 are sufficient to maintain signaling in a reporter assay at levels comparable with the full-length receptor, and identified important contributions from EGF repeats 8-10 in conveying an activating signal in response to either Dll1 or Dll4. Truncation studies of the Dll1 and Dll4 ectodomains showed that the MNNL-EGF3 region was both necessary and sufficient for full activation. Plate-based and cell binding assays revealed a specific, calcium-dependent interaction between cell-surface and recombinant Notch receptors and ligand molecules. Finally, direct measurement of the binding affinity of Notch1 EGF repeats 6-15 for Dll1 and Dll4 revealed that Dll4 binds with at least an order of magnitude higher affinity than Dll1. Together, these studies give new insights into the features of ligand recognition by Notch1, and highlight how intrinsic differences in the biochemical behavior of receptor-ligand complexes can influence receptor-mediated responses of developmental signaling pathways.
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Affiliation(s)
- Marie Blanke Andrawes
- From the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115,; the Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts 02115, and
| | - Xiang Xu
- From the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115,; the Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts 02115, and
| | - Hong Liu
- the Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts 02115, and
| | - Scott B Ficarro
- From the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115,; the Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts 02115, and
| | - Jarrod A Marto
- From the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115,; the Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts 02115, and
| | - Jon C Aster
- the Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Stephen C Blacklow
- From the Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115,; the Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts 02115, and.
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59
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Peterson NA, Anderson TK, Yoshino TP. In silico analysis of the fucosylation-associated genome of the human blood fluke Schistosoma mansoni: cloning and characterization of the fucosyltransferase multigene family. PLoS One 2013; 8:e63299. [PMID: 23696810 PMCID: PMC3655985 DOI: 10.1371/journal.pone.0063299] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 03/30/2013] [Indexed: 01/09/2023] Open
Abstract
Fucosylated glycans of the parasitic flatworm Schistosoma mansoni play key roles in its development and immunobiology. In the present study we used a genome-wide homology-based bioinformatics approach to search for genes that contribute to fucosylated glycan expression in S. mansoni, specifically the α2-, α3-, and α6-fucosyltransferases (FucTs), which transfer L-fucose from a GDP-L-fucose donor to an oligosaccharide acceptor. We identified and in silico characterized several novel schistosome FucT homologs, including six α3-FucTs and six α6-FucTs, as well as two protein O-FucTs that catalyze the unrelated transfer of L-fucose to serine and threonine residues of epidermal growth factor- and thrombospondin-type repeats. No α2-FucTs were observed. Primary sequence analyses identified key conserved FucT motifs as well as characteristic transmembrane domains, consistent with their putative roles as fucosyltransferases. Most genes exhibit alternative splicing, with multiple transcript variants generated. A phylogenetic analysis demonstrated that schistosome α3- and α6-FucTs form monophyletic clades within their respective gene families, suggesting multiple gene duplications following the separation of the schistosome lineage from the main evolutionary tree. Quantitative decreases in steady-state transcript levels of some FucTs during early larval development suggest a possible mechanism for differential expression of fucosylated glycans in schistosomes. This study systematically identifies the complete repertoire of FucT homologs in S. mansoni and provides fundamental information regarding their genomic organization, genetic variation, developmental expression, and evolutionary history.
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Affiliation(s)
- Nathan A. Peterson
- Department of Entomology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Tavis K. Anderson
- Virus and Prion Research Unit, National Animal Disease Center, United States Department of Agriculture, Agricultural Research Service, Ames, Iowa, United States of America
| | - Timothy P. Yoshino
- Department of Pathobiological Sciences, University of Wisconsin, Madison, Wisconsin, United States of America
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60
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Takeuchi H, Kantharia J, Sethi MK, Bakker H, Haltiwanger RS. Site-specific O-glucosylation of the epidermal growth factor-like (EGF) repeats of notch: efficiency of glycosylation is affected by proper folding and amino acid sequence of individual EGF repeats. J Biol Chem 2012; 287:33934-44. [PMID: 22872643 DOI: 10.1074/jbc.m112.401315] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
O-Glucosylation of epidermal growth factor-like (EGF) repeats in the extracellular domain of Notch is essential for Notch function. O-Glucose can be elongated by xylose to the trisaccharide, Xylα1-3Xylα1-3Glcβ1-O-Ser, whose synthesis is catalyzed by the consecutive action of three glycosyltransferases. A UDP-glucose:protein O-glucosyltransferase (Poglut/Rumi) transfers O-glucose to serine within the O-glucose consensus. Subsequently, either of two UDP-xylose:glucoside xylosyltransferases (Gxylt1 or Gxylt2) transfers xylose to O-glucose. Finally, a UDP-xylose:xyloside xylosyltransferase (Xxylt1) transfers xylose to Xylα1-3Glcβ1-O-EGF. Our prior site-mapping studies demonstrated that O-glucose consensus sites are modified at high but variable stoichiometries in mouse Notch1 and identified a novel glycosylation site with alanine in place of proline, suggesting a revised, broader consensus sequence (CXSX(P/A)C). Here we examined the molecular basis for this site specificity. A panel of EGF repeats from human coagulation factor 9 (FA9), mouse Notch1, and Notch2 were bacterially expressed and purified by reverse phase HPLC for use in in vitro enzyme assays. We demonstrate that proper folding of EGF repeats is essential for glycosylation by Poglut/Rumi, that alanine can substitute for proline in the context of coagulation factor 9 EGF repeat for O-glucose transfer, confirming the new consensus sequence, and that positively charged residues within the O-glucose consensus sequence reduce efficiency of glycosylation by Poglut/Rumi. Moreover, proper folding of EGF repeats is also important for the activities of Gxylt1, Gxylt2, and Xxylt1. These results indicate that protein folding and amino acid sequences of individual EGF repeats fundamentally affect both attachment and elongation of O-glucose glycans.
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Affiliation(s)
- Hideyuki Takeuchi
- Department of Biochemistry and Cell Biology, Institute of Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794, USA
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61
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Human deficiencies of fucosylation and sialylation affecting selectin ligands. Semin Immunopathol 2012; 34:383-99. [PMID: 22461019 DOI: 10.1007/s00281-012-0304-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 02/27/2012] [Indexed: 10/28/2022]
Abstract
Selectins are carbohydrate-binding adhesion molecules that are required for leukocyte trafficking to secondary lymphoid organs and to sites of infection. They interact with fucosylated and sialylated ligands bearing sialyl-Lewis X as a minimal carbohydrate structure. With this in mind, it should be expected that individuals with deficient fucosylation or sialylation show immunodeficiency. However, as this review shows, the picture appears to be more complex and more interesting. Although there are only few patients with such glycosylation defects, they have turned out to be very instructive for our understanding of the functions of fucosylation and sialylation in immunity, development and hemostasis.
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62
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Myeloproliferation and hematopoietic stem cell dysfunction due to defective Notch receptor modification by O-fucose glycans. Semin Immunopathol 2012; 34:455-69. [DOI: 10.1007/s00281-012-0303-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 02/24/2012] [Indexed: 02/01/2023]
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63
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Sethi MK, Buettner FFR, Ashikov A, Krylov VB, Takeuchi H, Nifantiev NE, Haltiwanger RS, Gerardy-Schahn R, Bakker H. Molecular cloning of a xylosyltransferase that transfers the second xylose to O-glucosylated epidermal growth factor repeats of notch. J Biol Chem 2012; 287:2739-48. [PMID: 22117070 PMCID: PMC3268431 DOI: 10.1074/jbc.m111.302406] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 11/14/2011] [Indexed: 11/06/2022] Open
Abstract
The extracellular domain of Notch contains epidermal growth factor (EGF) repeats that are extensively modified with different O-linked glycans. O-Fucosylation is essential for receptor function, and elongation with N-acetylglucosamine, catalyzed by members of the Fringe family, modulates Notch activity. Only recently, genes encoding enzymes involved in the O-glucosylation pathway have been cloned. In the Drosophila mutant rumi, characterized by a mutation in the protein O-glucosyltransferase, Notch signaling is impaired in a temperature-dependent manner, and a mouse knock-out leads to embryonic lethality. We have previously identified two human genes, GXYLT1 and GXYLT2, encoding glucoside xylosyltransferases responsible for the transfer of xylose to O-linked glucose. The identity of the enzyme further elongating the glycan to generate the final trisaccharide xylose-xylose-glucose, however, remained unknown. Here, we describe that the human gene C3ORF21 encodes a UDP-xylose:α-xyloside α1,3-xylosyltransferase, acting on xylose-α1,3-glucoseβ1-containing acceptor structures. We have, therefore, renamed it XXYLT1 (xyloside xylosyltransferase 1). XXYLT1 cannot act on a synthetic acceptor containing an α-linked xylose alone, but requires the presence of the underlying glucose. Activity on Notch EGF repeats was proven by in vitro xylosylation of a mouse Notch1 fragment recombinantly produced in Sf9 insect cells, a bacterially expressed EGF repeat from mouse Notch2 modified in vitro by Rumi and Gxylt2 and in vivo by co-expression of the enzyme with the Notch1 fragment. The enzyme was shown to be a typical type II membrane-bound glycosyltransferase localized in the endoplasmic reticulum.
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Affiliation(s)
- Maya K. Sethi
- From the Department of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Falk F. R. Buettner
- From the Department of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Angel Ashikov
- From the Department of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Vadim B. Krylov
- the Laboratory of Glycoconjugate Chemistry, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, 119991 Moscow, Russian Federation, and
| | - Hideyuki Takeuchi
- the Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Nikolay E. Nifantiev
- the Laboratory of Glycoconjugate Chemistry, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, 119991 Moscow, Russian Federation, and
| | - Robert S. Haltiwanger
- the Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Rita Gerardy-Schahn
- From the Department of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Hans Bakker
- From the Department of Cellular Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
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Sakaidani Y, Nomura T, Matsuura A, Ito M, Suzuki E, Murakami K, Nadano D, Matsuda T, Furukawa K, Okajima T. O-linked-N-acetylglucosamine on extracellular protein domains mediates epithelial cell-matrix interactions. Nat Commun 2011; 2:583. [PMID: 22158438 DOI: 10.1038/ncomms1591] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 11/11/2011] [Indexed: 01/11/2023] Open
Abstract
The O-linked-N-acetylglucosamine (O-GlcNAc) modification of cytoplasmic and nuclear proteins regulates basic cellular functions and is involved in the aetiology of diabetes and neurodegeneration. This intracellular O-GlcNAcylation is catalyzed by a single O-GlcNAc transferase, OGT. Here we report a novel OGT, EOGT, responsible for extracellular O-GlcNAcylation. Although both OGT and EOGT are regulated by hexosamine flux, EOGT localizes to the lumen of the endoplasmic reticulum and transfers GlcNAc to epidermal growth factor-like domains in an OGT-independent manner. Loss of Eogt gives phenotypes similar to those caused by defects in the apical extracellular matrix. Dumpy (Dp), a membrane-anchored extracellular protein, is O-GlcNAcylated, and EOGT is required for Dp-dependent epithelial cell-matrix interactions. Thus, O-GlcNAcylation of secreted and membrane glycoproteins is a novel mediator of cell-cell or cell-matrix interactions at the cell surface.
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Affiliation(s)
- Yuta Sakaidani
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, Japan
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Structural insights into the mechanism of protein O-fucosylation. PLoS One 2011; 6:e25365. [PMID: 21966509 PMCID: PMC3180450 DOI: 10.1371/journal.pone.0025365] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 09/01/2011] [Indexed: 01/17/2023] Open
Abstract
Protein O-fucosylation is an essential post-translational modification, involved in the folding of target proteins and in the role of these target proteins during embryonic development and adult tissue homeostasis, among other things. Two different enzymes are responsible for this modification, Protein O-fucosyltransferase 1 and 2 (POFUT1 and POFUT2, respectively). Both proteins have been characterised biologically and enzymatically but nothing is known at the molecular or structural level. Here we describe the first crystal structure of a catalytically functional POFUT1 in an apo-form and in complex with GDP-fucose and GDP. The enzyme belongs to the GT-B family and is not dependent on manganese for activity. GDP-fucose/GDP is localised in a conserved cavity connected to a large solvent exposed pocket, which we show is the binding site of epidermal growth factor (EGF) repeats in the extracellular domain of the Notch Receptor. Through both mutational and kinetic studies we have identified which residues are involved in binding and catalysis and have determined that the Arg240 residue is a key catalytic residue. We also propose a novel S(N)1-like catalytic mechanism with formation of an intimate ion pair, in which the glycosidic bond is cleaved before the nucleophilic attack; and theoretical calculations at a DFT (B3LYP/6-31+G(d,p) support this mechanism. Thus, the crystal structure together with our mutagenesis studies explain the molecular mechanism of POFUT1 and provide a new starting point for the design of functional inhibitors to this critical enzyme in the future.
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66
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Rana NA, Haltiwanger RS. Fringe benefits: functional and structural impacts of O-glycosylation on the extracellular domain of Notch receptors. Curr Opin Struct Biol 2011; 21:583-9. [PMID: 21924891 DOI: 10.1016/j.sbi.2011.08.008] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/08/2011] [Accepted: 08/23/2011] [Indexed: 01/22/2023]
Abstract
The Notch family of receptors plays essential roles in many phases of development, and dysregulation of Notch activity is increasingly recognized as a player in many diseases. O-Glycosylation of the Notch extracellular domain is essential for Notch activity, and tissue-specific alterations in the glycan structures are known to regulate activity. Here we review recent advances in identification and characterization of the enzymes responsible for glycosylating Notch and molecular mechanisms for how these O-glycans affect Notch activity.
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Affiliation(s)
- Nadia A Rana
- Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA
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67
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Rana NA, Nita-Lazar A, Takeuchi H, Kakuda S, Luther KB, Haltiwanger RS. O-glucose trisaccharide is present at high but variable stoichiometry at multiple sites on mouse Notch1. J Biol Chem 2011; 286:31623-37. [PMID: 21757702 PMCID: PMC3173066 DOI: 10.1074/jbc.m111.268243] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 07/01/2011] [Indexed: 12/26/2022] Open
Abstract
Notch activity is regulated by both O-fucosylation and O-glucosylation, and Notch receptors contain multiple predicted sites for both. Here we examine the occupancy of the predicted O-glucose sites on mouse Notch1 (mN1) using the consensus sequence C(1)XSXPC(2). We show that all of the predicted sites are modified, although the efficiency of modifying O-glucose sites is site- and cell type-dependent. For instance, although most sites are modified at high stoichiometries, the site at EGF 27 is only partially glucosylated, and the occupancy of the site at EGF 4 varies with cell type. O-Glucose is also found at a novel, non-traditional consensus site at EGF 9. Based on this finding, we propose a revision of the consensus sequence for O-glucosylation to allow alanine N-terminal to cysteine 2: C(1)XSX(A/P)C(2). We also show through biochemical and mass spectral analyses that serine is the only hydroxyamino acid that is modified with O-glucose on EGF repeats. The O-glucose at all sites is efficiently elongated to the trisaccharide Xyl-Xyl-Glc. To establish the functional importance of individual O-glucose sites in mN1, we used a cell-based signaling assay. Elimination of most individual sites shows little or no effect on mN1 activation, suggesting that the major effects of O-glucose are mediated by modification of multiple sites. Interestingly, elimination of the site in EGF 28, found in the Abruptex region of Notch, does significantly reduce activity. These results demonstrate that, like O-fucose, the O-glucose modifications of EGF repeats occur extensively on mN1, and they play important roles in Notch function.
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Affiliation(s)
- Nadia A. Rana
- From the Department of Biochemistry and Cell Biology, Institute of Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Aleksandra Nita-Lazar
- From the Department of Biochemistry and Cell Biology, Institute of Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Hideyuki Takeuchi
- From the Department of Biochemistry and Cell Biology, Institute of Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Shinako Kakuda
- From the Department of Biochemistry and Cell Biology, Institute of Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Kelvin B. Luther
- From the Department of Biochemistry and Cell Biology, Institute of Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Robert S. Haltiwanger
- From the Department of Biochemistry and Cell Biology, Institute of Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
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68
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Protein O-fucosyltransferase 1 (Pofut1) regulates lymphoid and myeloid homeostasis through modulation of Notch receptor ligand interactions. Blood 2011; 117:5652-62. [PMID: 21464368 DOI: 10.1182/blood-2010-12-326074] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Notch signaling is essential for lymphocyte development and is also implicated in myelopoiesis. Notch receptors are modified by O-fucosylation catalyzed by protein O-fucosyltransferase 1 (Pofut1). Fringe enzymes add N-acetylglucosamine to O-fucose and modify Notch signaling by altering the sensitivity of Notch receptors to Notch ligands. To address physiologic functions in hematopoiesis of Notch modified by O-fucose glycans, we examined mice with inducible inactivation of Pofut1 using Mx-Cre. These mice exhibited a reduction in T lymphopoiesis and in the production of marginal-zone B cells, in addition to myeloid hyperplasia. Restoration of Notch1 signaling rescued T lymphopoiesis and the marrow myeloid hyperplasia. After marrow transfer, both cell-autonomous and environmental cues were found to contribute to lymphoid developmental defects and myeloid hyperplasia in Pofut1-deleted mice. Although Pofut1 deficiency slightly decreased cell surface expression of Notch1 and Notch2, it completely abrogated the binding of Notch receptors with Delta-like Notch ligands and suppressed downstream Notch target activation, indicating that O-fucose glycans are critical for efficient Notch-ligand binding that transduce Notch signals. The combined data support a key role for the O-fucose glycans generated by Pofut1 in Notch regulation of hematopoietic homeostasis through modulation of Notch-ligand interactions.
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69
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Chapman G, Sparrow DB, Kremmer E, Dunwoodie SL. Notch inhibition by the ligand Delta-Like 3 defines the mechanism of abnormal vertebral segmentation in spondylocostal dysostosis. Hum Mol Genet 2010; 20:905-16. [DOI: 10.1093/hmg/ddq529] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Lu L, Hou X, Shi S, Körner C, Stanley P. Slc35c2 promotes Notch1 fucosylation and is required for optimal Notch signaling in mammalian cells. J Biol Chem 2010; 285:36245-54. [PMID: 20837470 DOI: 10.1074/jbc.m110.126003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mammalian Notch receptors require modification by fucose on epidermal growth factor-like (EGF) repeats of their extracellular domain to respond optimally to signal induction by canonical Notch ligands. Inactivation of the Golgi GDP-fucose transporter Slc35c1 in mouse or human does not cause marked defects in Notch signaling during development, and shows milder fucosylation defects than those observed in mice unable to synthesize GDP-fucose, indicating the existence of another mechanism for GDP-fucose transport into the secretory pathway. We show here that fibroblasts from mice or humans lacking Slc35c1 exhibit robust Notch signaling in co-culture signaling assays. A potential candidate for a second GDP-fucose transporter is the related gene Slc35c2. Overexpression of Slc35c2 reduces expression of the fucosylated epitopes Lewis X and sialylated Lewis X in CHO cells, indicating competition with Slc35c1. The fucosylation of a Notch1 EGF repeat fragment that occurs in the endoplasmic reticulum was increased in CHO transfectants overexpressing Slc35c2. In CHO cells with low levels of Slc35c2, both Delta1- and Jagged1-induced Notch signaling were reduced, and the fucosylation of a Notch1 fragment was also decreased. Immunofluorescence microscopy of rat intestinal epithelial cells and HeLa cells, and analysis of rat liver membrane fractions showed that Slc35c2 is primarily colocalized with markers of the cis-Golgi network and endoplasmic reticulum-Golgi intermediate compartment (ERGIC). The combined results suggest that Slc35c2 is either a GDP-fucose transporter that competes with Slc35c1 for GDP-fucose, or a factor that otherwise enhances the fucosylation of Notch and is required for optimal Notch signaling in mammalian cells.
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Affiliation(s)
- Linchao Lu
- Department of Cell Biology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461, USA
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71
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Rendić D, Sharrow M, Katoh T, Overcarsh B, Nguyen K, Kapurch J, Aoki K, Wilson IBH, Tiemeyer M. Neural-specific α3-fucosylation of N-linked glycans in the Drosophila embryo requires fucosyltransferase A and influences developmental signaling associated with O-glycosylation. Glycobiology 2010; 20:1353-65. [PMID: 20688784 DOI: 10.1093/glycob/cwq119] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Addition of fucose (Fuc) to glycoprotein N-linked glycans or in O-linkage directly to Ser/Thr residues modulates specific cell-cell interactions and cell signaling events. Vertebrates and invertebrates add Fuc in α6-linkage to the reducing terminal N-acetylglucosamine residue of N-glycans. In Drosophila and other invertebrates, Fuc can also be added in α3-linkage to the same residue. These difucosylated N-glycans are recognized by anti-horseradish peroxidase (anti-HRP) antisera, providing a well-established marker for insect neural tissue. To understand the mechanisms and consequences of tissue-specific glycan expression, we identified a single α3-fucosyltransferase (FucTA) that produces the anti-HRP epitope in Drosophila embryos. FucTA transcripts are temporally and spatially restricted to cells that express the anti-HRP epitope and are missing in a mutant that lacks neural α3-fucosylation. Transgenic expression of FucTA, but not of any other candidate α3-fucosyltransferase, rescues the anti-HRP epitope in the embryonic nervous system of this mutant. Mass spectrometric characterization of the N-glycans of Drosophila embryos overexpressing FucTA confirms that this enzyme is indeed responsible for the biosynthesis of difucosylated glycans in vivo. Whereas ectopic expression of FucTA in the larval wing disc produces mild wing notching, the heterochronic, pan-neural expression of FucTA in early differentiating neurons generates neurogenic and cell migration phenotypes; this latter effect is associated with reduced GDP-Fuc levels in the embryo and indicates that the diversion of fucosylation resources towards fucosylation of N-glycans has an impact on developmental signaling associated with O-fucosylation.
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Affiliation(s)
- Dubravko Rendić
- Department für Chemie, Universität für Bodenkultur, A-1190 Wien, Austria
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72
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Park D, Choi D, Lee J, Lim DS, Park C. Male-like sexual behavior of female mouse lacking fucose mutarotase. BMC Genet 2010; 11:62. [PMID: 20609214 PMCID: PMC2912782 DOI: 10.1186/1471-2156-11-62] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 07/07/2010] [Indexed: 12/15/2022] Open
Abstract
Background Mutarotases are recently characterized family of enzymes that are involved in the anomeric conversions of monosaccharides. The mammalian fucose mutarotase (FucM) was reported in cultured cells to facilitate fucose utilization and incorporation into protein by glycosylation. However, the role of this enzyme in animal has not been elucidated. Results We generated a mutant mouse specifically lacking the fucose mutarotase (FucM) gene. The FucM knockout mice displayed an abnormal sexual receptivity with a drastic reduction in lordosis score, although the animals were fertile due to a rare and forced intromission by a typical male. We examined the anteroventral periventricular nucleus (AVPv) of the preoptic region in brain and found that the mutant females showed a reduction in tyrosine hydoxylase positive neurons compared to that of a normal female. Furthermore, the mutant females exhibited a masculine behavior, such as mounting to a normal female partner as well as showing a preference to female urine. We found a reduction of fucosylated serum alpha-fetoprotein (AFP) in a mutant embryo relative to that of a wild-type embryo. Conclusions The observation that FucM-/- female mouse exhibits a phenotypic similarity to a wild-type male in terms of its sexual behavior appears to be due to the neurodevelopmental changes in preoptic area of mutant brain resembling a wild-type male. Since the previous studies indicate that AFP plays a role in titrating estradiol that are required to consolidate sexual preference of female mice, we speculate that the reduced level of AFP in FucM-/- mouse, presumably resulting from the reduced fucosylation, is responsible for the male-like sexual behavior observed in the FucM knock-out mouse.
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Affiliation(s)
- Dongkyu Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-Gu, Daejon 305-701, Korea
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73
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Jafar-Nejad H, Leonardi J, Fernandez-Valdivia R. Role of glycans and glycosyltransferases in the regulation of Notch signaling. Glycobiology 2010; 20:931-49. [PMID: 20368670 DOI: 10.1093/glycob/cwq053] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The evolutionarily conserved Notch signaling pathway plays broad and important roles during embryonic development and in adult tissue homeostasis. Unlike most other pathways used during animal development, Notch signaling does not rely on second messengers and intracellular signaling cascades. Instead, pathway activation results in the cleavage of the Notch intracellular domain and its translocation into the nucleus, where it functions as a transcriptional co-activator of the Notch target genes. To ensure tight spatial and temporal regulation of a pathway with such an unusually direct signaling transduction, animal cells have devised a variety of specialized modulatory mechanisms. One such mechanism takes advantage of decorating the Notch extracellular domain with rare types of O-linked glycans. In this review, we will discuss the genetic and biochemical data supporting the notion that carbohydrate modification is essential for Notch signaling and attempt to provide a brief historical overview of how we have learned what we know about the glycobiology of Notch. We will also summarize what is known about the contribution of specific nucleotide-sugar transporters to Notch biology and the roles-enzymatic and non-enzymatic-played by specific glycosyltransferases in the regulation of this pathway. Mutations in the Notch pathway components cause a variety of human diseases, and manipulation of Notch signaling is emerging as a powerful tool in regenerative medicine. Therefore, studying how sugar modification modulates Notch signaling provides a framework for better understanding the role of glycosylation in animal development and might offer new tools to manipulate Notch signaling for therapeutic purposes.
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74
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Takeuchi H, Haltiwanger RS. Role of glycosylation of Notch in development. Semin Cell Dev Biol 2010; 21:638-45. [PMID: 20226260 DOI: 10.1016/j.semcdb.2010.03.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 03/02/2010] [Accepted: 03/03/2010] [Indexed: 11/26/2022]
Abstract
The Notch pathway is one of the major signaling pathways required for proper development in metazoans. Notch activity is regulated at numerous levels, and increasing evidence reveals the importance of "protein glycosylation" (modification of Notch receptors with sugars) for its regulation. In this review we summarize the significance of the Notch pathway in development and the players responsible for its glycosylation, and then discuss the molecular mechanisms by which protein glycosylation may regulate Notch function.
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Affiliation(s)
- Hideyuki Takeuchi
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA
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75
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Abstract
Notch and the DSL Notch ligands Delta and Serrate/Jagged are glycoproteins with a single transmembrane domain. The extracellular domain (ECD) of both Notch receptors and Notch ligands contains numerous epidermal growth factor (EGF)-like repeats which are post-translationally modified by a variety of glycans. Inactivation of a subset of genes that encode glycosyltransferases which initiate and elongate these glycans inhibits Notch signaling. In the formation of developmental boundaries in Drosophila and mammals, in mouse T-cell and marginal zone B-cell development, and in co-culture Notch signaling assays, the regulation of Notch signaling by glycans is to date a cell-autonomous effect of the Notch-expressing cell. The regulation of Notch signaling by glycans represents a new paradigm of signal transduction. O-fucose glycans modulate the strength of Notch binding to DSL Notch ligands, while O-glucose glycans facilitate juxta-membrane cleavage of Notch, generating the substrate for intramembrane cleavage and Notch activation. Identifying precisely how the addition of particular sugars at specific locations on Notch modifies Notch signaling is a challenge for the future.
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Affiliation(s)
- Pamela Stanley
- Department of Cell Biology, Albert Einstein College Medicine, New York, USA
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76
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Oka T, Saito F, Shimma YI, Yoko-o T, Nomura Y, Matsuoka K, Jigami Y. Characterization of endoplasmic reticulum-localized UDP-D-galactose: hydroxyproline O-galactosyltransferase using synthetic peptide substrates in Arabidopsis. PLANT PHYSIOLOGY 2010; 152:332-40. [PMID: 19923238 PMCID: PMC2799367 DOI: 10.1104/pp.109.146266] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2009] [Accepted: 11/10/2009] [Indexed: 05/19/2023]
Abstract
We characterized peptidyl hydroxyproline (Hyp) O-galactosyltransferase (HGT), which is the initial enzyme in the arabinogalactan biosynthetic pathway. An in vitro assay of HGT activity was established using chemically synthesized fluorescent peptides as acceptor substrates and extracts from Arabidopsis (Arabidopsis thaliana) T87 cells as a source of crude enzyme. The galactose residue transferred to the peptide could be detected by high-performance liquid chromatography and matrix-assisted laser desorption-ionization time-of-flight mass spectrometry analyses. HGT required a divalent cation of manganese for maximal activity and consumed UDP-D-galactose as a sugar donor. HGT exhibited an optimal pH range of pH 7.0 to 8.0 and an optimal temperature of 35 degrees C. The favorable substrates for the activity seemed to be peptides containing two alternating imino acid residues including at least one acceptor Hyp residue, although a peptide with single Hyp residue without any other imino acids also functioned as a substrate. The results of sucrose density gradient centrifugation revealed that the cellular localization of HGT activity is identical to those of endoplasmic reticulum markers such as Sec61 and Bip, indicating that HGT is predominantly localized to the endoplasmic reticulum. To our knowledge, this is the first characterization of HGT, and the data provide evidence that arabinogalactan biosynthesis occurs in the protein transport pathway.
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77
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78
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Ishikawa HO, Ayukawa T, Nakayama M, Higashi S, Kamiyama S, Nishihara S, Aoki K, Ishida N, Sanai Y, Matsuno K. Two pathways for importing GDP-fucose into the endoplasmic reticulum lumen function redundantly in the O-fucosylation of Notch in Drosophila. J Biol Chem 2009; 285:4122-4129. [PMID: 19948734 DOI: 10.1074/jbc.m109.016964] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Notch is a transmembrane receptor that shares homology with proteins containing epidermal growth factor-like repeats and mediates the cell-cell interactions necessary for many cell fate decisions. In Drosophila, O-fucosyltransferase 1 catalyzes the O-fucosylation of these epidermal growth factor-like repeats. This O-fucose elongates, resulting in an O-linked tetrasaccharide that regulates the signaling activities of Notch. Fucosyltransferases utilize GDP-fucose, which is synthesized in the cytosol, but fucosylation occurs in the lumen of the endoplasmic reticulum (ER) and Golgi. Therefore, GDP-fucose uptake into the ER and Golgi is essential for fucosylation. However, although GDP-fucose biosynthesis is well understood, the mechanisms and intracellular routes of GDP-fucose transportation remain unclear. Our previous study on the Drosophila Golgi GDP-fucose transporter (Gfr), which specifically localizes to the Golgi, suggested that another GDP-fucose transporter(s) exists in Drosophila. Here, we identified Efr (ER GDP-fucose transporter), a GDP-fucose transporter that localizes specifically to the ER. Efr is a multifunctional nucleotide sugar transporter involved in the biosynthesis of heparan sulfate-glycosaminoglycan chains and the O-fucosylation of Notch. Comparison of the fucosylation defects in the N-glycans in Gfr and Efr mutants revealed that Gfr and Efr made distinct contributions to this modification; Gfr but not Efr was crucial for the fucosylation of N-glycans. We also found that Gfr and Efr function redundantly in the O-fucosylation of Notch, although they had different localizations and nucleotide sugar transportation specificities. These results indicate that two pathways for the nucleotide sugar supply, involving two nucleotide sugar transporters with distinct characteristics and distributions, contribute to the O-fucosylation of Notch.
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Affiliation(s)
- Hiroyuki O Ishikawa
- From the Genome and Drug Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510
| | - Tomonori Ayukawa
- the Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510
| | - Minoru Nakayama
- From the Genome and Drug Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510
| | - Shunsuke Higashi
- the Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510
| | - Shin Kamiyama
- the Department of Bioinformatics, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, and
| | - Shoko Nishihara
- the Department of Bioinformatics, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, and
| | - Kazuhisa Aoki
- the Department of Biochemical Cell Research, Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan
| | - Nobuhiro Ishida
- the Department of Biochemical Cell Research, Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan
| | - Yutaka Sanai
- the Department of Biochemical Cell Research, Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan
| | - Kenji Matsuno
- From the Genome and Drug Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510; the Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510.
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Affiliation(s)
- Robert S. Haltiwanger
- Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, Stony Brook Univeristy, Stony Brook, NY 11794-5215, Phone: 631-632-7336, FAX: 631-632-8575,
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Mutation of the fucose-specific β1,3 N-acetylglucosaminyltransferase LFNG results in abnormal formation of the spine. Biochim Biophys Acta Mol Basis Dis 2009; 1792:100-11. [DOI: 10.1016/j.bbadis.2008.11.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 10/31/2008] [Accepted: 11/04/2008] [Indexed: 01/24/2023]
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82
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Mollicone R, Moore SE, Bovin N, Garcia-Rosasco M, Candelier JJ, Martinez-Duncker I, Oriol R. Activity, Splice Variants, Conserved Peptide Motifs, and Phylogeny of Two New α1,3-Fucosyltransferase Families (FUT10 and FUT11). J Biol Chem 2009; 284:4723-38. [DOI: 10.1074/jbc.m809312200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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83
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Luther KB, Schindelin H, Haltiwanger RS. Structural and mechanistic insights into lunatic fringe from a kinetic analysis of enzyme mutants. J Biol Chem 2008; 284:3294-3305. [PMID: 19028689 DOI: 10.1074/jbc.m805502200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Notch receptor is critical for proper development where it orchestrates numerous cell fate decisions. The Fringe family of beta1,3-N-acetylglucosaminyltransferases are regulators of this pathway. Fringe enzymes add N-acetylglucosamine to O-linked fucose on the epidermal growth factor repeats of Notch. Here we have analyzed the reaction catalyzed by Lunatic Fringe (Lfng) in detail. A mutagenesis strategy for Lfng was guided by a multiple sequence alignment of Fringe proteins and solutions from docking an epidermal growth factor-like O-fucose acceptor substrate onto a homology model of Lfng. We targeted three main areas as follows: residues that could help resolve where the fucose binds, residues in two conserved loops not observed in the published structure of Manic Fringe, and residues predicted to be involved in UDP-N-acetylglucosamine (UDP-GlcNAc) donor specificity. We utilized a kinetic analysis of mutant enzyme activity toward the small molecule acceptor substrate 4-nitrophenyl-alpha-L-fucopyranoside to judge their effect on Lfng activity. Our results support the positioning of O-fucose in a specific orientation to the catalytic residue. We also found evidence that one loop closes off the active site coincident with, or subsequent to, substrate binding. We propose a mechanism whereby the ordering of this short loop may alter the conformation of the catalytic aspartate. Finally, we identify several residues near the UDP-GlcNAc-binding site, which are specifically permissive toward UDP-GlcNAc utilization.
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Affiliation(s)
- Kelvin B Luther
- Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Hermann Schindelin
- Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Robert S Haltiwanger
- Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, Stony Brook University, Stony Brook, New York 11794-5215.
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84
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Luther KB, Haltiwanger RS. Role of unusual O-glycans in intercellular signaling. Int J Biochem Cell Biol 2008; 41:1011-24. [PMID: 18952191 DOI: 10.1016/j.biocel.2008.10.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 09/22/2008] [Accepted: 10/03/2008] [Indexed: 01/09/2023]
Abstract
In the last two decades, our knowledge of the role of glycans in development and signal transduction has expanded enormously. While most work has focused on the importance of N-linked or mucin-type O-linked glycosylation, recent work has highlighted the importance of several more unusual forms of glycosylation that are the focus of this review. In particular, the ability of O-fucose glycans on the epidermal growth factor-like (EGF) repeats of Notch to modulate signaling places glycosylation alongside phosphorylation as a means to modulate protein-protein interactions and their resultant downstream signals. The recent discovery that O-glucose modification of Notch EGF repeats is also required for Notch function has further expanded the range of glycosylation events capable of modulating Notch signaling. The prominent role of Notch during development and in later cell-fate decisions underscores the importance of these modifications in human biology. The role of glycans in intercellular signaling events is only beginning to be understood and appears ready to expand into new areas with the discovery that thrombospondin type 1 repeats are also modified with O-fucose glycans. Finally, a rare form of glycosylation called C-mannosylation modifies tryptophans in some signaling competent molecules and may be a further layer of complexity in the field. We will review each of these areas focusing on the glycan structures produced, the consequence of their presence, and the enzymes responsible.
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Affiliation(s)
- Kelvin B Luther
- Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA
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85
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Okamura Y, Saga Y. Pofut1 is required for the proper localization of the Notch receptor during mouse development. Mech Dev 2008; 125:663-73. [PMID: 18547789 DOI: 10.1016/j.mod.2008.04.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Revised: 04/25/2008] [Accepted: 04/30/2008] [Indexed: 11/19/2022]
Abstract
Protein O-fucosyltransferase 1 (Pofut1), which catalyzes the addition of O-linked fucose to the EGF domains of the Notch receptor, is indispensable for Notch signaling activation. However, the mechanism of action of Pofut1 in mice is still unclear. Mouse embryos lacking Pofut1 shows defects in valve formation and trabeculation in the cardiovascular system, which are almost identical abnormalities to those of the RBP-Jk mutants. In our current study, we have examined the epistatic relationship between the functions of Pofut1 and activated-Notch1 (NICD1) by taking advantage of the fact that forced expression of NICD1 results in myocardial defects. These defects were still evident in NICD1-expressing embryos irrespective of the presence or absence of Pofut1, which indicates that Pofut1 is required for Notch signaling upstream of NICD1. We further found that Pofut1-null cells do not possess normally localized Notch1 receptors, which may results in their lack of interaction with the Dll1 ligand in the presomitic mesoderm where Notch signaling plays a pivotal role. We propose that altered trafficking pathways may account for the abnormal accumulation of the Notch1 receptor in the endoplasmic reticulum in Pofut1-null mouse embryos.
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Affiliation(s)
- Yoshiaki Okamura
- Department of Genetics, SOKENDAI, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
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86
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Gebauer JM, Müller S, Hanisch FG, Paulsson M, Wagener R. O-glucosylation and O-fucosylation occur together in close proximity on the first epidermal growth factor repeat of AMACO (VWA2 protein). J Biol Chem 2008; 283:17846-54. [PMID: 18434322 DOI: 10.1074/jbc.m704820200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AMACO (VWA2 protein) is an extracellular matrix protein of unknown function associated with certain basement membranes in skin, lung, and kidney. AMACO is a member of the von Willebrand factor A-like (VWA) domain containing protein superfamily and in addition to three VWA domains it also contains two epidermal growth factor-like domains. One of these contains the rare, overlapping consensus sequences for both O-glucosylation and O-fucosylation. In earlier studies of other proteins the attachment of either core glucose and fucose moieties or of the respective elongated glycans starting with these monosaccharides has been described. By a detailed mass spectrometric analysis we show that both elongated O-glucosylated (Xyl1-3Xyl1-3Glc) and elongated O-fucosylated glycan chains (NeuAc2-3Gal1-4GlcNAc1-3Fuc) can be attached to AMACO in close proximity on the same epidermal growth factor-like domain. It has been reported that the lack of O-fucosylation can markedly decrease secretion of proteins. However, the secretion of AMACO is not significantly affected when the glycosylation sites are mutated. The number of extracellular matrix proteins carrying the overlapping consensus sequence is very limited and it could be that these modifications have a new, yet unknown function.
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Affiliation(s)
- Jan M Gebauer
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
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87
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Functions of O-fucosyltransferase in Notch trafficking and signaling: towards the end of a controversy? J Biol 2008; 7:7. [PMID: 18312702 PMCID: PMC2263122 DOI: 10.1186/jbiol68] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The precise role of the O-fucosyltransferase Ofut1 in Notch-receptor trafficking has remained controversial. A recent study sheds new light on the non-catalytic activity of Ofut1 and provides further evidence that Ofut1 acts as a chaperone in the endoplasmic reticulum.
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88
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Abstract
Notch signaling regulates cell fate during the development of many tissues. A new Drosophila mutant, rumi, is defective in Notch signaling because it cannot add glucose to serine in epidermal growth factor repeats of Notch extracellular domain. This is the first biological role for glucose covalently attached to a cell surface signaling receptor.
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Affiliation(s)
- Pamela Stanley
- Department of Cell Biology, Albert Einstein College of Medicine, New York, New York 10461
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89
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Okajima T, Matsuura A, Matsuda T. Biological functions of glycosyltransferase genes involved in O-fucose glycan synthesis. J Biochem 2008; 144:1-6. [PMID: 18272537 DOI: 10.1093/jb/mvn016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Rare types of glycosylation often occur in a domain-specific manner and are involved in specific biological processes. Well-known examples of such modification are O-linked fucose (O-fucose) and O-linked glucose (O-glucose) glycans on epidermal growth factor (EGF) domains. In particular, O-fucose glycans are reported to regulate the functions of EGF domain-containing proteins such as urinary-type plasminogen activator and Notch receptors. Two glycosyltransferases catalyze the initiation and elongation of O-fucose glycans. The initiation process is catalyzed by O-fucosyltransferase 1, which is essential for Notch signalling in both Drosophila and mice. O-fucosyltransferase 1 can affect the folding, ligand interaction and endocytosis of Notch receptors, and both the glycosyltransferase and non-catalytic activities of O-fucosyltransferase 1 have been reported. The elongation of O-fucose monosaccharide is catalyzed by Fringe-related genes, which differentially modulate the interaction between Notch and two classes of ligands, namely, Delta and Serrate/Jagged. In this article, we have reviewed the recent reports addressing the distinctive features of the glycosyltransferases and O-glycans present on the EGF domains.
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Affiliation(s)
- Tetsuya Okajima
- Nagoya University Graduate School of Bioagricultural Sciences, Department of Applied Molecular Biosciences, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
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90
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Lin CH, Lin CW, Khoo KH. Proteomic identification of specific glycosyltransferases functionally implicated for the biosynthesis of a targeted glyco-epitope. Proteomics 2008; 8:475-83. [DOI: 10.1002/pmic.200700710] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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91
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Okajima T, Reddy B, Matsuda T, Irvine KD. Contributions of chaperone and glycosyltransferase activities of O-fucosyltransferase 1 to Notch signaling. BMC Biol 2008; 6:1. [PMID: 18194540 PMCID: PMC2242781 DOI: 10.1186/1741-7007-6-1] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 01/14/2008] [Indexed: 12/25/2022] Open
Abstract
Background O-fucosyltransferase1 (OFUT1) is a conserved ER protein essential for Notch signaling. OFUT1 glycosylates EGF domains, which can then be further modified by the N-acetylglucosaminyltransferase Fringe. OFUT1 also possesses a chaperone activity that promotes the folding and secretion of Notch. Here, we investigate the respective contributions of these activities to Notch signaling in Drosophila. Results We show that expression of an isoform lacking fucosyltransferase activity, Ofut1R245A, rescues the requirement for Ofut1 in embryonic neurogenesis. Lack of requirement for O-fucosylation is further supported by the absence of embryonic phenotypes in Gmd mutants, which lack all forms of fucosylation. Requirements for O-fucose during imaginal development were evaluated by characterizing clones of cells expressing only Ofut1R245A. These clones phenocopy fringe mutant clones, indicating that the absence of O-fucose is functionally equivalent to the absence of elongated O-fucose. Conclusion Our results establish that Notch does not need to be O-fucosylated for fringe-independent Notch signaling in Drosophila; the chaperone activity of OFUT1 is sufficient for the generation of functional Notch.
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Affiliation(s)
- Tetsuya Okajima
- Nagoya University Graduate School of Bioagricultural Sciences, Department of Applied Molecular Biosciences, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
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92
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93
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Narimatsu Y, Ikehara Y, Iwasaki H, Nonomura C, Sato T, Nakanishi H, Narimatsu H. Immunocytochemical analysis for intracellular dynamics of C1GalT associated with molecular chaperone, Cosmc. Biochem Biophys Res Commun 2007; 366:199-205. [PMID: 18061573 DOI: 10.1016/j.bbrc.2007.11.121] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 11/20/2007] [Indexed: 10/22/2022]
Abstract
The core 1 structure Galbeta1-3GalNAcalpha1-Ser/Thr (T antigen), the major constituent of O-glycan core structure, is synthesized by cooperation of core 1 synthase (C1GalT) and its specific molecular chaperone, Cosmc. The chaperone function of Cosmc has been well investigated biochemically. In this study, we established monoclonal antibodies specifically recognizing either C1GalT or Cosmc, respectively, and investigated the sub-cellular localization of each protein to elucidate how they cooperate to synthesize the core 1 structure. A sequential immunocytochemical analysis of the human colon cancer cell line, LSB, demonstrated different localization of two proteins. C1GalT was localized in Golgi apparatus, while Cosmc was localized in endoplasmic reticulum. In contrast, the LSC cells, which do not have core 1 synthase activity due to a missense mutation in the Cosmc gene, did not express the C1GalT protein. Although the treatment with a proteasome inhibitor, lactacystin, of LSC cells resulted in the increased expression of C1GalT protein, the distribution of C1GalT was not in Golgi apparatus as seen in LSB cells. On the contrary, overexpression of Cosmc but not C1GalT lead to precise localization of C1GalT protein, which distributed in Golgi apparatus and recovered the core 1 synthase activity in LSC cells. These results suggest that the intracellular dynamics of C1GalT is controlled by its specific molecular chaperon, Cosmc, in association with core 1 synthase activity.
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Affiliation(s)
- Yoshiki Narimatsu
- Glycogene Function Team of Research Center for Medical Glycoscience (RCMG), National Institute of Advanced Industrial Science and Technology (AIST), Open Space Laboratory Central-2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
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94
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Stanley P. Regulation of Notch signaling by glycosylation. Curr Opin Struct Biol 2007; 17:530-5. [PMID: 17964136 DOI: 10.1016/j.sbi.2007.09.007] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 08/17/2007] [Accepted: 09/18/2007] [Indexed: 12/21/2022]
Abstract
Notch receptors are approximately 300 kDa cell surface glycoproteins whose activation by Notch ligands regulates cell fate decisions in the metazoa. The extracellular domain of Notch receptors has many epidermal growth factor like repeats that are glycosylated with O-fucose and O-glucose glycans as well as N-glycans. Disruption of O-fucose glycan synthesis leads to severe Notch signaling defects in Drosophila and mammals. Removal or addition of O-fucose glycan consensus sites on Notch receptors also leads to Notch signaling defects. Ligand binding and ligand-induced Notch signaling assays have provided insights into how changes in the O-fucose glycans of Notch receptors alter Notch signaling.
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Affiliation(s)
- Pamela Stanley
- Department Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave., New York, NY 10461, United States.
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95
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Hellbusch CC, Sperandio M, Frommhold D, Yakubenia S, Wild MK, Popovici D, Vestweber D, Gröne HJ, von Figura K, Lübke T, Körner C. Golgi GDP-fucose Transporter-deficient Mice Mimic Congenital Disorder of Glycosylation IIc/Leukocyte Adhesion Deficiency II. J Biol Chem 2007; 282:10762-72. [PMID: 17276979 DOI: 10.1074/jbc.m700314200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Modification of glycoproteins by the attachment of fucose residues is widely distributed in nature. The importance of fucosylation has recently been underlined by identification of the monogenetic inherited human disease "congenital disorder of glycosylation IIc," also termed "leukocyte adhesion deficiency II." Due to defective Golgi GDP-fucose transporter (SLC35C1) activity, patients show a hypofucosylation of glycoproteins and present clinically with mental and growth retardation, persistent leukocytosis, and severe infections. To investigate effects induced by the loss of fucosylated structures in different organs, we generated a mouse model for the disease by inactivating the Golgi GDP-transporter gene (Slc35c1). Lectin binding studies revealed a tremendous reduction of fucosylated glycoconjugates in tissues and isolated cells from Slc35c1(-/-) mice. Fucose treatment of cells from different organs led to partial normalization of the fucosylation state of glycoproteins, thereby indicating an alternative GDP-fucose transport mechanism. Slc35c1-deficient mice presented with severe growth retardation, elevated postnatal mortality rate, dilatation of lung alveoles, and hypocellular lymph nodes. In vitro and in vivo leukocyte adhesion and rolling assays revealed a severe impairment of P-, E-, and L-selectin ligand function. The diversity of these phenotypic aspects demonstrates the broad general impact of fucosylation in the mammalian organism.
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Affiliation(s)
- Christina C Hellbusch
- Department of Pediatrics, Division of Inborn Metabolic Diseases, Section of Neonatology, University Children's Hospital, Im Neuenheimer Feld 153, 69120 Heidelberg, Germany
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96
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Ricketts LM, Dlugosz M, Luther KB, Haltiwanger RS, Majerus EM. O-fucosylation is required for ADAMTS13 secretion. J Biol Chem 2007; 282:17014-23. [PMID: 17395589 DOI: 10.1074/jbc.m700317200] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
ADAMTS13 is a plasma metalloproteinase that cleaves von Willebrand factor to smaller, less thrombogenic forms. Deficiency of ADAMTS13 activity in plasma leads to thrombotic thrombocytopenic purpura. ADAMTS13 contains eight thrombospondin type 1 repeats (TSR), seven of which contain a consensus sequence for the direct addition of fucose to the hydroxyl group of serine or threonine. Mass spectral analysis of tryptic peptides derived from human ADAMTS13 indicate that at least six of the TSRs are modified with an O-fucose disaccharide. Analysis of [(3)H]fucose metabolically incorporated into ADAMTS13 demonstrated that the disaccharide has the structure glucose-beta1,3-fucose. Mutation of the modified serine to alanine in TSR2, TSR5, TSR7, and TSR8 reduced the secretion of ADAMTS13. Mutation of more than one site dramatically reduced secretion regardless of the sites mutated. When the expression of protein O-fucosyltransferase 2 (POFUT2), the enzyme that transfers fucose to serines in TSRs, was reduced using siRNA, the secretion of ADAMTS13 decreased. A similar outcome was observed when ADAMTS13 was expressed in a cell line unable to synthesize the donor for fucose addition, GDP-fucose. Although overexpression of POFUT2 did not affect the secretion of wild-type ADAMTS13, it did increase the secretion of the ADAMTS13 TSR1,2 double mutant but not that of ADAMTS13 TSR1-8 mutant. Together these findings indicate that O-fucosylation is functionally significant for secretion of ADAMTS13.
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Affiliation(s)
- Lindsay M Ricketts
- Department of Internal Medicine, Division of Hematology, Washington University School of Medicine, St. Louis, Missouri, 63110, USA
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97
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Wang LW, Dlugosz M, Somerville RPT, Raed M, Haltiwanger RS, Apte SS. O-fucosylation of thrombospondin type 1 repeats in ADAMTS-like-1/punctin-1 regulates secretion: implications for the ADAMTS superfamily. J Biol Chem 2007; 282:17024-31. [PMID: 17395588 DOI: 10.1074/jbc.m701065200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ADAMTS superfamily contains several metalloproteases (ADAMTS proteases) as well as ADAMTS-like molecules that lack proteolytic activity. Their common feature is the presence of one or more thrombospondin type-1 repeats (TSRs) within a characteristic modular organization. ADAMTS like-1/punctin-1 has four TSRs. Previously, O-fucosylation on Ser or Thr mediated by the endoplasmic reticulum-localized enzyme protein-O-fucosyltransferase 2 (POFUT2) was described for TSRs of thrombospondin-1, properdin, and F-spondin within the sequence Cys-Xaa(1)-Xaa(2)-(Ser/Thr)-Cys-Xaa-Xaa-Gly (where the fucosylated residue is underlined). On mass spectrometric analysis of tryptic peptides from recombinant secreted human punctin-1, the appropriate peptides from TSR2, TSR3, and TSR4 were found to bear either a fucose monosaccharide (TSR3, TSR4) or a fucose-glucose disaccharide (TSR2, TSR3, TSR4). Although mass spectral analysis did not unambiguously identify the relevant peptide from TSR1, metabolic labeling of cells expressing TSR1 and the cysteine-rich module led to incorporation of [(3)H]fucose into this construct. Mutation of the putative modified Ser/Thr residues in TSR2, TSR3, and TSR4 led to significantly decreased levels of secreted punctin-1. Similarly, expression of punctin-1 in Lec-13 cells that are deficient in conversion of GDP-mannose to GDP-fucose substantially decreased the levels of secreted protein, which were restored upon culture in the presence of exogenous l-fucose. In addition, mutation of the single N-linked oligosaccharide in punctin-1 led to decreased levels of secreted punctin-1. Taken together, the data define a critical role for N-glycosylation and O-fucosylation in the biosynthesis of punctin-1. From a broad perspective, these data suggest that O-fucosylation may be a widespread post-translational modification in members of the ADAMTS superfamily with possible regulatory consequences.
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Affiliation(s)
- Lauren W Wang
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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98
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Loriol C, Audfray A, Dupuy F, Germot A, Maftah A. The two N-glycans present on bovine Pofut1 are differently involved in its solubility and activity. FEBS J 2007; 274:1202-11. [PMID: 17263732 DOI: 10.1111/j.1742-4658.2007.05663.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
O-Fucosylation is a post-translational glycosylation in which an O-fucose is covalently attached to the hydroxyl group of a specific serine or threonine residue. This modification occurs within the consensus sequence C2X(4-5)(S/T)C3 present on epidermal growth factor-like repeats of several proteins, including the Notch receptors and their ligands. The enzyme responsible for the addition of O-fucose to epidermal growth factor-like repeats is protein O-fucosyltransferase 1. Protein O-fucosyltransferase 1-mediated O-fucosylation is essential in Notch signaling, folding and targeting to the cell surface. Here, we studied the expression pattern of protein O-fucosyltransferase 1 in cattle and showed that the active enzyme is present in all tissues examined from embryo and adult as a glycoprotein with two N-glycans. By comparing protein O-fucosyltransferase 1 sequences available in databases, we observed that mammalian protein O-fucosyltransferase 1 enzymes possess two putative N-glycosylation sites, and that only the first is conserved among bilaterians. To gain more insight regarding the significance of N-glycans on protein O-fucosyltransferase 1, we substituted, by site-directed mutagenesis, bovine protein O-fucosyltransferase 1 N65, N163 or both, with L or Q. We demonstrated that the loss of N-glycan on N163 caused a slight decrease in protein O-fucosyltransferase 1 activity. In contrast, glycosylation of N65 was crucial for protein O-fucosyltransferase 1 functionality. Loss of glycosylation at N65 resulted in aggregation of protein O-fucosyltransferase 1, suggesting that N-glycosylation at this site is essential for proper folding of the enzyme.
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Affiliation(s)
- Céline Loriol
- INRA, UMR1061 Unité de Génétique Moléculaire Animale, GDR-CNRS 2590, Université de Limoges, IFR 45, Faculté des Sciences et Techniques, 87060 Limoges, France
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99
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Etzioni A. Leukocyte adhesion deficiencies: molecular basis, clinical findings, and therapeutic options. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 601:51-60. [PMID: 17712991 DOI: 10.1007/978-0-387-72005-0_5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Leukocyte trafficking from bloodstream to tissue is important for the continuous surveillance for foreign antigens, as well as for rapid leukocyte accumulation at sites of inflammatory response or tissue injury. Leukocyte interaction with vascular endothelial cells is a pivotal event in the inflammatory response and is mediated by several families of adhesion molecules. The crucial role of the beta2-integrin subfamily in leukocyte emigration was established after leukocyte adhesion deficiency (LAD) I was discovered. Patients with this disorder suffer from life-threatening bacterial infections, and in its severe form, death usually occurs in early childhood unless bone marrow transplantation is performed. The LAD II disorder clarifies the role of the selectin receptors and their fucosylated ligands. Clinically, patients with LAD II suffer from a less severe form of disease, resembling the moderate phenotype of LAD I. LAD III emphasizes the importance of the integrin activation phase in the adhesion cascade. Although the primary defect is still unknown, it is clear that all hematopoietic integrin activation processes are defective, which lead to severe infection as observed in LAD I and to marked increase tendency for bleeding problems.
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Affiliation(s)
- Amos Etzioni
- Meyer Children Hospital, the Rappaport School of Medicine, Technion, Haifa, Israel.
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100
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Kozma K, Keusch JJ, Hegemann B, Luther KB, Klein D, Hess D, Haltiwanger RS, Hofsteenge J. Identification and characterization of abeta1,3-glucosyltransferase that synthesizes the Glc-beta1,3-Fuc disaccharide on thrombospondin type 1 repeats. J Biol Chem 2006; 281:36742-51. [PMID: 17032646 DOI: 10.1074/jbc.m605912200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombospondin type 1 repeats (TSRs) are biologically important domains of extracellular proteins. They are modified with a unique Glcbeta1,3Fucalpha1-O-linked disaccharide on either serine or threonine residues. Here we identify the putative glycosyltransferase, B3GTL, as the beta1,3-glucosyltransferase involved in the biosynthesis of this disaccharide. This enzyme is conserved from Caenorhabditis elegans to man and shares 28% sequence identity with Fringe, the beta1,3-N-acetylglucosaminyltransferase that modifies O-linked fucosyl residues in proteins containing epidermal growth factor-like domains, such as Notch. beta1,3-Glucosyltransferase glucosylates properly folded TSR-fucose but not fucosylated epidermal growth factor-like domain or the non-fucosylated modules. Specifically, the glucose is added in a beta1,3-linkage to the fucose in TSR. The activity profiles of beta1,3-glucosyltransferase and protein O-fucosyltransferase 2, the enzyme that carries out the first step in TSR O-fucosylation, superimpose in endoplasmic reticulum subfractions obtained by density gradient centrifugation. Both enzymes are soluble proteins that efficiently modify properly folded TSR modules. The identification of the beta1,3-glucosyltransferase gene allows us to manipulate the formation of the rare Glcbeta1,3Fucalpha1 structure to investigate its biological function.
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Affiliation(s)
- Krisztina Kozma
- Friedrich Miescher Institute, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
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