401
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Shi H, Drummond CA, Fan X, Haller ST, Liu J, Malhotra D, Tian J. Hiding inside? Intracellular expression of non-glycosylated c-kit protein in cardiac progenitor cells. Stem Cell Res 2016; 16:795-806. [PMID: 27161312 DOI: 10.1016/j.scr.2016.04.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 04/15/2016] [Accepted: 04/22/2016] [Indexed: 12/23/2022] Open
Abstract
Cardiac progenitor cells including c-kit(+) cells and cardiosphere-derived cells (CDCs) play important roles in cardiac repair and regeneration. CDCs were reported to contain only small subpopulations of c-kit(+) cells and recent publications suggested that depletion of the c-kit(+) subpopulation of cells has no effect on regenerative properties of CDCs. However, our current study showed that the vast majority of CDCs from murine heart actually express c-kit, albeit, in an intracellular and non-glycosylated form. Immunostaining and flow cytometry showed that the fluorescent signal indicative of c-kit immunostaining significantly increased when cell membranes were permeabilized. Western blots further demonstrated that glycosylation of c-kit was increased during endothelial differentiation in a time dependent manner. Glycosylation inhibition by 1-deoxymannojirimycin hydrochloride (1-DMM) blocked c-kit glycosylation and reduced expression of endothelial cell markers such as Flk-1 and CD31 during differentiation. Pretreatment of these cells with a c-kit kinase inhibitor (imatinib mesylate) also attenuated Flk-1 and CD31 expression. These results suggest that c-kit glycosylation and its kinase activity are likely needed for these cells to differentiate into an endothelial lineage. In vivo, we found that intracellular c-kit expressing cells are located in the wall of cardiac blood vessels in mice subjected to myocardial infarction. In summary, our work demonstrated for the first time that c-kit is not only expressed in CDCs but may also directly participate in CDC differentiation into an endothelial lineage.
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Affiliation(s)
- Huilin Shi
- Department of Medicine, Division of Cardiovascular Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43614, USA
| | - Christopher A Drummond
- Department of Medicine, Division of Cardiovascular Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43614, USA
| | - Xiaoming Fan
- Department of Medicine, Division of Cardiovascular Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43614, USA
| | - Steven T Haller
- Department of Medicine, Division of Cardiovascular Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43614, USA
| | - Jiang Liu
- Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Deepak Malhotra
- Department of Medicine, Division of Cardiovascular Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43614, USA
| | - Jiang Tian
- Department of Medicine, Division of Cardiovascular Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, OH 43614, USA.
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402
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Ellgaard L, McCaul N, Chatsisvili A, Braakman I. Co- and Post-Translational Protein Folding in the ER. Traffic 2016; 17:615-38. [PMID: 26947578 DOI: 10.1111/tra.12392] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/26/2016] [Accepted: 03/03/2016] [Indexed: 12/19/2022]
Abstract
The biophysical rules that govern folding of small, single-domain proteins in dilute solutions are now quite well understood. The mechanisms underlying co-translational folding of multidomain and membrane-spanning proteins in complex cellular environments are often less clear. The endoplasmic reticulum (ER) produces a plethora of membrane and secretory proteins, which must fold and assemble correctly before ER exit - if these processes fail, misfolded species accumulate in the ER or are degraded. The ER differs from other cellular organelles in terms of the physicochemical environment and the variety of ER-specific protein modifications. Here, we review chaperone-assisted co- and post-translational folding and assembly in the ER and underline the influence of protein modifications on these processes. We emphasize how method development has helped advance the field by allowing researchers to monitor the progression of folding as it occurs inside living cells, while at the same time probing the intricate relationship between protein modifications during folding.
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Affiliation(s)
- Lars Ellgaard
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nicholas McCaul
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Anna Chatsisvili
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
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403
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Zacchi LF, Schulz BL. SWATH-MS Glycoproteomics Reveals Consequences of Defects in the Glycosylation Machinery. Mol Cell Proteomics 2016; 15:2435-47. [PMID: 27094473 DOI: 10.1074/mcp.m115.056366] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Indexed: 12/16/2022] Open
Abstract
Glycan macro- and microheterogeneity have profound impacts on protein folding and function. This heterogeneity can be regulated by physiological or environmental factors. However, unregulated heterogeneity can lead to disease, and mutations in the glycosylation process cause a growing number of Congenital Disorders of Glycosylation. We systematically studied how mutations in the N-glycosylation pathway lead to defects in mature proteins using all viable Saccharomyces cerevisiae strains with deletions in genes encoding Endoplasmic Reticulum lumenal mannosyltransferases (Alg3, Alg9, and Alg12), glucosyltransferases (Alg6, Alg8, and Die2/Alg10), or oligosaccharyltransferase subunits (Ost3, Ost5, and Ost6). To measure the changes in glycan macro- and microheterogeneity in mature proteins caused by these mutations we developed a SWATH-mass spectrometry glycoproteomics workflow. We measured glycan structures and occupancy on mature cell wall glycoproteins, and relative protein abundance, in the different mutants. All mutants showed decreased glycan occupancy and altered cell wall proteomes compared with wild-type cells. Mutations in earlier mannosyltransferase or glucosyltransferase steps of glycan biosynthesis had stronger hypoglycosylation phenotypes, but glucosyltransferase defects were more severe. ER mannosyltransferase mutants displayed substantial global changes in glycan microheterogeneity consistent with truncations in the glycan transferred to protein in these strains. Although ER glucosyltransferase and oligosaccharyltransferase subunit mutants broadly showed no change in glycan structures, ost3Δ cells had shorter glycan structures at some sites, consistent with increased protein quality control mannosidase processing in this severely hypoglycosylating mutant. This method allows facile relative quantitative glycoproteomics, and our results provide insights into global regulation of site-specific glycosylation.
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Affiliation(s)
- Lucia F Zacchi
- From the ‡School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, 4072, Australia; §Fundación Instituto Leloir, Avenida Patricias Argentinas 435, Ciudad Autónoma de Buenos Aires, 1405, Argentina
| | - Benjamin L Schulz
- From the ‡School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, 4072, Australia;
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404
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Loke I, Kolarich D, Packer NH, Thaysen-Andersen M. Emerging roles of protein mannosylation in inflammation and infection. Mol Aspects Med 2016; 51:31-55. [PMID: 27086127 DOI: 10.1016/j.mam.2016.04.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/05/2016] [Accepted: 04/10/2016] [Indexed: 02/07/2023]
Abstract
Proteins are frequently modified by complex carbohydrates (glycans) that play central roles in maintaining the structural and functional integrity of cells and tissues in humans and lower organisms. Mannose forms an essential building block of protein glycosylation, and its functional involvement as components of larger and diverse α-mannosidic glycoepitopes in important intra- and intercellular glycoimmunological processes is gaining recognition. With a focus on the mannose-rich asparagine (N-linked) glycosylation type, this review summarises the increasing volume of literature covering human and non-human protein mannosylation, including their structures, biosynthesis and spatiotemporal expression. The review also covers their known interactions with specialised host and microbial mannose-recognising C-type lectin receptors (mrCLRs) and antibodies (mrAbs) during inflammation and pathogen infection. Advances in molecular mapping technologies have recently revealed novel immuno-centric mannose-terminating truncated N-glycans, termed paucimannosylation, on human proteins. The cellular presentation of α-mannosidic glycoepitopes on N-glycoproteins appears tightly regulated; α-mannose determinants are relative rare glycoepitopes in physiological extracellular environments, but may be actively secreted or leaked from cells to transmit potent signals when required. Simultaneously, our understanding of the molecular basis on the recognition of mannosidic epitopes by mrCLRs including DC-SIGN, mannose receptor, mannose binding lectin and mrAb is rapidly advancing, together with the functional implications of these interactions in facilitating an effective immune response during physiological and pathophysiological conditions. Ultimately, deciphering these complex mannose-based receptor-ligand interactions at the detailed molecular level will significantly advance our understanding of immunological disorders and infectious diseases, promoting the development of future therapeutics to improve patient clinical outcomes.
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Affiliation(s)
- Ian Loke
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Daniel Kolarich
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Nicolle H Packer
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Morten Thaysen-Andersen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia.
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405
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A subunit of the oligosaccharyltransferase complex is required for interspecific gametophyte recognition in Arabidopsis. Nat Commun 2016; 7:10826. [PMID: 26964640 PMCID: PMC4792959 DOI: 10.1038/ncomms10826] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 01/21/2016] [Indexed: 12/11/2022] Open
Abstract
Species-specific gamete recognition is a key premise to ensure reproductive success and the maintenance of species boundaries. During plant pollen tube (PT) reception, gametophyte interactions likely allow the species-specific recognition of signals from the PT (male gametophyte) by the embryo sac (female gametophyte), resulting in PT rupture, sperm release, and double fertilization. This process is impaired in interspecific crosses between Arabidopsis thaliana and related species, leading to PT overgrowth and a failure to deliver the sperm cells. Here we show that ARTUMES (ARU) specifically regulates the recognition of interspecific PTs in A. thaliana. ARU, identified in a genome-wide association study (GWAS), exclusively influences interspecific--but not intraspecific--gametophyte interactions. ARU encodes the OST3/6 subunit of the oligosaccharyltransferase complex conferring protein N-glycosylation. Our results suggest that glycosylation patterns of cell surface proteins may represent an important mechanism of gametophyte recognition and thus speciation.
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406
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Serum Antibodies to Glycans in Peripheral Neuropathies. Mol Neurobiol 2016; 54:1564-1567. [PMID: 26867654 DOI: 10.1007/s12035-016-9775-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 02/02/2016] [Indexed: 01/26/2023]
Abstract
In peripheral neuropathies, such as sensorimotor neuropathies, motor neuron diseases, or the Guillain-Barré syndrome, serum antibodies recognizing saccharide units, portion of oligosaccharides, or oligosaccharide chains, have been found. These antibodies are called anti-glycosphingolipid (GSL) or anti-ganglioside antibodies. However, the information on the aglycone carrying the hydrophilic oligosaccharide remains elusive. The absolute and unique association of GSL to the onset, development and symptomatology of the peripheral neuropathies could be misleading. Here, we report some thoughts on the matter.
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407
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Mammalian cells lacking either the cotranslational or posttranslocational oligosaccharyltransferase complex display substrate-dependent defects in asparagine linked glycosylation. Sci Rep 2016; 6:20946. [PMID: 26864433 PMCID: PMC4750078 DOI: 10.1038/srep20946] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/13/2016] [Indexed: 02/01/2023] Open
Abstract
Asparagine linked glycosylation of proteins is an essential protein modification reaction in most eukaryotic organisms. Metazoan organisms express two oligosaccharyltransferase complexes that are composed of a catalytic subunit (STT3A or STT3B) assembled with a shared set of accessory subunits and one to two complex specific subunits. siRNA mediated knockdowns of STT3A and STT3B in HeLa cells have shown that the two OST complexes have partially non-overlapping roles in N-linked glycosylation. However, incomplete siRNA mediated depletion of STT3A or STT3B reduces the impact of OST complex loss, thereby complicating the interpretation of experimental results. Here, we have used the CRISPR/Cas9 gene editing technology to create viable HEK293 derived cells lines that are deficient for a single catalytic subunit (STT3A or STT3B) or two STT3B-specific accessory subunits (MagT1 and TUSC3). Analysis of protein glycosylation in the STT3A, STT3B and MagT1/TUSC3 null cell lines revealed that these cell lines are superior tools for investigating the in vivo role and substrate preferences of the STT3A and STT3B complexes.
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408
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Han M, Yu X. Enhanced expression of heterologous proteins in yeast cells via the modification of N-glycosylation sites. Bioengineered 2016; 6:115-8. [PMID: 25671496 DOI: 10.1080/21655979.2015.1011031] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Yeasts are widely used for the production of heterologous proteins. Improving the expression of such proteins is a top priority for pharmaceutical and industrial applications. N-Glycosylation, a common form of protein modification in yeasts, facilitates proper protein folding and secretion. Accordingly, our previous study revealed that the attachment of additional N-glycans to recombinant elastase by introducing an N-glycosylation sequon at suitable locations could stimulate its expression. Interestingly, the sequon Asn-Xaa-Thr is N-glycosylated more efficiently than Asn-Xaa-Ser, so improving the N-glycosylation efficiency via the conversion of Ser to Thr in the sequon would enhance the efficiency of N-glycosylation and increase glycoprotein expression. Recently, the expression level of recombinant elastase was enhanced by this means in our lab. Actually, the modification of N-glycosylation sites can generally be achieved through site-directed mutagenesis; thus, the method described in this report represents a feasible means of improving heterologous protein expression in yeasts.
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Affiliation(s)
- Minghai Han
- a Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake; School of Life Sciences; Huaiyin Normal University ; Huaian , China
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409
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Rosenlöcher J, Sandig G, Kannicht C, Blanchard V, Reinke SO, Hinderlich S. Recombinant glycoproteins: The impact of cell lines and culture conditions on the generation of protein species. J Proteomics 2016; 134:85-92. [DOI: 10.1016/j.jprot.2015.08.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 07/31/2015] [Accepted: 08/18/2015] [Indexed: 10/23/2022]
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410
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Trempel F, Kajiura H, Ranf S, Grimmer J, Westphal L, Zipfel C, Scheel D, Fujiyama K, Lee J. Altered glycosylation of exported proteins, including surface immune receptors, compromises calcium and downstream signaling responses to microbe-associated molecular patterns in Arabidopsis thaliana. BMC PLANT BIOLOGY 2016; 16:31. [PMID: 26822404 PMCID: PMC4730752 DOI: 10.1186/s12870-016-0718-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/19/2016] [Indexed: 05/10/2023]
Abstract
BACKGROUND Calcium, as a second messenger, transduces extracellular signals into cellular reactions. A rise in cytosolic calcium concentration is one of the first plant responses after exposure to microbe-associated molecular patterns (MAMPs). We reported previously the isolation of Arabidopsis thaliana mutants with a "changed calcium elevation" (cce) response to flg22, a 22-amino-acid MAMP derived from bacterial flagellin. RESULTS Here, we characterized the cce2 mutant and its weaker allelic mutant, cce3. Besides flg22, the mutants respond with a reduced calcium elevation to several other MAMPs and a plant endogenous peptide that is proteolytically processed from pre-pro-proteins during wounding. Downstream defense-related events such flg22-induced mitogen-activated protein kinase activation, accumulation of reactive oxygen species and growth arrest are also attenuated in cce2/cce3. By genetic mapping, next-generation sequencing and allelism assay, CCE2/CCE3 was identified to be ALG3 (Asparagine-linked glycosylation 3). This encodes the α-1,3-mannosyltransferase responsible for the first step of core oligosaccharide Glc3Man9GlcNAc2 glycan assembly on the endoplasmic reticulum (ER) luminal side. Complementation assays and glycan analysis in yeast alg3 mutant confirmed the reduced enzymatic function of the proteins encoded by the cce2/cce3 alleles - leading to accumulation of M5(ER), the immature five mannose-containing oligosaccharide structure found in the ER. Proper protein glycosylation is required for ER/Golgi processing and trafficking of membrane proteins to the plasma membrane. Endoglycosidase H-insensitivity of flg22 receptor, FLS2, in the cce2/cce3 mutants suggests altered glycan structures in the receptor. CONCLUSION Proper glycosylation of MAMP receptors (or other exported proteins) is required for optimal responses to MAMPs and is important for immune signaling of host plants.
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Affiliation(s)
- Fabian Trempel
- Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle/Saale, Germany.
| | - Hiroyuki Kajiura
- The International Center for Biotechnology, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka, 565, Japan.
| | - Stefanie Ranf
- Current address: Phytopathology, TUM School of Life Sciences, Weihenstephan, Technische Universität München, Emil-Ramann-Str. 2, D-85350, Freising-Weihenstephan, Germany.
| | - Julia Grimmer
- Current address: Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Weinbergweg 22, D-06120, Halle, Germany.
| | - Lore Westphal
- Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle/Saale, Germany.
| | - Cyril Zipfel
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK.
| | - Dierk Scheel
- Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle/Saale, Germany.
| | - Kazuhito Fujiyama
- The International Center for Biotechnology, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka, 565, Japan.
| | - Justin Lee
- Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle/Saale, Germany.
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411
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Classical galactosaemia: novel insights in IgG N-glycosylation and N-glycan biosynthesis. Eur J Hum Genet 2016; 24:976-84. [PMID: 26733289 DOI: 10.1038/ejhg.2015.254] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/20/2015] [Accepted: 10/27/2015] [Indexed: 01/05/2023] Open
Abstract
Classical galactosaemia (OMIM #230400), a rare disorder of carbohydrate metabolism, is caused by a deficient activity of galactose-1-phosphate uridyltransferase (EC 2.7.7.12). The pathophysiology of the long-term complications, mainly cognitive, neurological and female fertility problems remains poorly understood. The lack of validated biomarkers to determine prognosis, monitor disease progression and responses to new therapies, pose a huge challenge. We report the detailed analysis of an automated robotic hydrophilic interaction ultra-performance liquid chromatography N-glycan analytical method of high glycan peak resolution applied to serum IgG. This has revealed specific N-glycan processing defects observed in 40 adult galactosaemia patients (adults and adolescents), in comparison with 81 matched healthy controls. We have identified a significant increase in core fucosylated neutral glycans (P<0.0001) and a significant decrease in core fucosylated (P<0.001), non-fucosylated (P<0.0001) bisected glycans and, of specific note, decreased N-linked mannose-5 glycans (P<0.0001), in galactosaemia patients. We also report the abnormal expression of a number of related relevant N-glycan biosynthesis genes in peripheral blood mononuclear cells from 32 adult galactosaemia patients. We have noted significant dysregulation of two key N-glycan biosynthesis genes: ALG9 upregulated (P<0.001) and MGAT1 downregulated (P<0.01) in galactosaemia patients, which may contribute to its ongoing pathophysiology. Our data suggest that the use of IgG N-glycosylation analysis with matched N-glycan biosynthesis gene profiles may provide useful biomarkers for monitoring response to therapy and interventions. They also indicate potential gene modifying steps in this N-glycan biosynthesis pathway, of relevance to galactosaemia and related N-glycan biosynthesis disorders.
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412
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Harada Y. Biosynthesis and Degradation of Dolichol-Linked Oligosaccharides. TRENDS GLYCOSCI GLYC 2016. [DOI: 10.4052/tigg.1512.1j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Yoichiro Harada
- Department of Systems Biology in Thromboregulation, Kagoshima University
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413
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Affiliation(s)
- Yoichiro Harada
- Department of Systems Biology in Thromboregulation, Kagoshima University
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414
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Matoba N. N-Glycosylation of Cholera Toxin B Subunit: Serendipity for Novel Plant-Made Vaccines? FRONTIERS IN PLANT SCIENCE 2015; 6:1132. [PMID: 26732492 PMCID: PMC4686596 DOI: 10.3389/fpls.2015.01132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 11/29/2015] [Indexed: 05/28/2023]
Abstract
The non-toxic B subunit of cholera toxin (CTB) has attracted considerable interests from vaccinologists due to strong mucosal immunomodulatory effects and potential utility as a vaccine scaffold for heterologous antigens. Along with other conventional protein expression systems, various plant species have been used as production hosts for CTB and its fusion proteins. However, it has recently become clear that the protein is N-glycosylated within the endoplasmic reticulum of plant cells-a eukaryotic post-translational modification that is not present in native CTB. While functionally active aglycosylated variants have been successfully engineered to circumvent potential safety and regulatory issues related to glycosylation, this modification may actually provide advantageous characteristics to the protein as a vaccine platform. Based on data from our recent studies, I discuss the unique features of N-glycosylated CTB produced in plants for the development of novel vaccines.
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415
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Zacchi LF, Schulz BL. N-glycoprotein macroheterogeneity: biological implications and proteomic characterization. Glycoconj J 2015; 33:359-76. [DOI: 10.1007/s10719-015-9641-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 11/04/2015] [Accepted: 11/20/2015] [Indexed: 10/22/2022]
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416
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Identification and characterization of transcriptional control region of the human beta 1,4-mannosyltransferase gene. Cytotechnology 2015; 69:417-434. [PMID: 26608959 DOI: 10.1007/s10616-015-9929-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 11/02/2015] [Indexed: 10/22/2022] Open
Abstract
All asparagine-linked glycans (N-glycans) on the eukaryotic glycoproteins are primarily derived from dolichol-linked oligosaccharides (DLO), synthesized on the rough endoplasmic reticulum membrane. We have previously reported cloning and identification of the human gene, HMT-1, which encodes chitobiosyldiphosphodolichol beta-mannosyltransferase (β1,4-MT) involved in the early assembly of DLO. Considering that N-glycosylation is one of the most ubiquitous post-translational modifications for many eukaryotic proteins, the HMT-1 could be postulated as one of the housekeeping genes, but its transcriptional regulation remains to be investigated. Here we screened a 1 kb region upstream from HMT-1 open reading frame (ORF) for transcriptionally regulatory sequences by using chloramphenicol acetyl transferase (CAT) assay, and found that the region from -33 to -1 positions might act in HMT-1 transcription at basal level and that the region from -200 to -42 should regulate its transcription either positively or negatively. In addition, results with CAT assays suggested the possibility that two GATA-1 motifs and an Sp1 motif within a 200 bp region upstream from HMT-1 ORF might significantly upregulate HMT-1 transcription. On the contrary, the observations obtained from site-directed mutational analyses revealed that an NF-1/AP-2 overlapping motif located at -148 to -134 positions should serve as a strong silencer. The control of the HMT-1 transcription by these motifs resided within the 200 bp region could partially explain the variation of expression level among various human tissues, suggesting availability and importance of this region for regulatory role in HMT-1 expression.
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417
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Mills DC, Jervis AJ, Abouelhadid S, Yates LE, Cuccui J, Linton D, Wren BW. Functional analysis of N-linking oligosaccharyl transferase enzymes encoded by deep-sea vent proteobacteria. Glycobiology 2015; 26:398-409. [PMID: 26610891 DOI: 10.1093/glycob/cwv111] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/20/2015] [Indexed: 01/04/2023] Open
Abstract
Bacterial N-linking oligosaccharyl transferases (OTase enzymes) transfer lipid-linked glycans to selected proteins in the periplasm and were first described in the intestinal pathogen Campylobacter jejuni, a member of the ε-proteobacteria-subdivision of bacteria. More recently, orthologues from other ε-proteobacterial Campylobacter and Helicobacter species and a δ-proteobacterium, Desulfovibrio desulfuricans, have been described, suggesting that these two subdivisions of bacteria may be a source of further N-linked protein glycosylation systems. Whole-genome sequencing of both ε- and δ-proteobacteria from deep-sea vent habitats, a rich source of species from these subdivisions, revealed putative ORFs encoding OTase enzymes and associated adjacent glycosyltransferases similar to the C. jejuni N-linked glycosylation locus. We expressed putative OTase ORFs from the deep-sea vent species Nitratiruptor tergarcus, Sulfurovum lithotrophicum and Deferribacter desulfuricans in Escherichia coli and showed that they were able to functionally complement the C. jejuni OTase, CjPglB. The enzymes were shown to possess relaxed glycan specificity, transferring diverse glycan structures and demonstrated different glycosylation sequon specificities. Additionally, a permissive D. desulfuricans acceptor protein was identified, and we provide evidence that the N-linked glycan synthesized by N. tergarcus and S. lithotrophicum contains an acetylated sugar at the reducing end. This work demonstrates that deep-sea vent bacteria encode functional N-glycosylation machineries and are a potential source of biotechnologically important OTase enzymes.
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Affiliation(s)
- Dominic C Mills
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
| | - Adrian J Jervis
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Manchester M13 9PT, UK
| | - Sherif Abouelhadid
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
| | - Laura E Yates
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
| | - Jon Cuccui
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
| | - Dennis Linton
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Manchester M13 9PT, UK
| | - Brendan W Wren
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, University of London, Keppel Street, London WC1E 7HT, UK
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418
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Ding Y, Jones GM, Brimacombe C, Uchida K, Aizawa SI, Logan SM, Kelly JF, Jarrell KF. Identification of a gene involved in the biosynthesis pathway of the terminal sugar of the archaellin N-linked tetrasaccharide in Methanococcus maripaludis. Antonie van Leeuwenhoek 2015; 109:131-48. [PMID: 26590834 DOI: 10.1007/s10482-015-0615-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 10/28/2015] [Indexed: 10/22/2022]
Abstract
In Methanococcus maripaludis, the three archaellins which comprise the archaellum are modified at multiple sites with an N-linked tetrasaccharide with the structure of Sug-4-β-ManNAc3NAmA6Thr-4-β-GlcNAc3NAcA-3-β-GalNAc, where Sug is a unique sugar (5S)-2-acetamido-2,4-dideoxy-5-O-methyl-L-erythro-hexos-5-ulo-1,5-pyranose, so far found exclusively in this species. In this study, a six-gene cluster mmp1089-1094, neighboring one of the genomic regions already known to contain genes involved with the archaellin N-glycosylation pathway, was examined for its potential involvement in the archaellin N-glycosylation or sugar biosynthesis pathway. The co-transcription of these six genes was demonstrated by RT-PCR. Mutants carrying an in-frame deletion in mmp1090, mmp1091 or mmp1092 were successfully generated. The Δmmp1090 deletion mutant was archaellated when examined by electron microscopy and mass spectrometry analysis of purified archaella showed that the archaellins were modified with a truncated N-glycan in which the terminal sugar residue and the threonine linked to the third sugar residue were missing. Both gene annotation and bioinformatic analyses indicate that MMP1090 is a UDP-glucose 4-epimerase, suggesting that the unique terminal sugar of the archaellin N-glycan might be synthesised from UDP-glucose or UDP-N-acetylglucosamine with an essential early step in synthesis catalysed by MMP1090. In contrast, no detectable phenotype related to archaellin glycosylation was observed in mutants deleted for either mmp1091 or mmp1092 while attempts to delete mmp1089, mmp1093 and mmp1094 were unsuccessful. Based on its demonstrated involvement in the archaellin N-glycosylation pathway, we designated mmp1090 as aglW.
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Affiliation(s)
- Yan Ding
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, K7L 3N6, Canada
| | - Gareth M Jones
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, K7L 3N6, Canada
| | - Cedric Brimacombe
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, K7L 3N6, Canada
| | - Kaoru Uchida
- Department of Life Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima, 727-0023, Japan
| | - Shin-Ichi Aizawa
- Department of Life Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima, 727-0023, Japan
| | - Susan M Logan
- Human Health Therapeutics Portfolio, National Research Council, Ottawa, K1A 0R6, Canada
| | - John F Kelly
- Human Health Therapeutics Portfolio, National Research Council, Ottawa, K1A 0R6, Canada.
| | - Ken F Jarrell
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, K7L 3N6, Canada.
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419
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D'Alessio C, Dahms NM. Glucosidase II and MRH-domain containing proteins in the secretory pathway. Curr Protein Pept Sci 2015; 16:31-48. [PMID: 25692846 DOI: 10.2174/1389203716666150213160438] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/25/2014] [Accepted: 11/13/2014] [Indexed: 12/24/2022]
Abstract
N-glycosylation in the endoplasmic reticulum (ER) consists of the transfer of a preassembled glycan conserved among species (Glc3Man9GlcNAc2) from a lipid donor to a consensus sequence within a nascent protein that is entering the ER. The protein-linked glycans are then processed by glycosidases and glycosyltransferases in the ER producing specific structures that serve as signalling molecules for the fate of the folding glycoprotein: to stay in the ER during the folding process, to be retrotranslocated to the cytosol for proteasomal degradation if irreversibly misfolded, or to pursue transit through the secretory pathway as a mature glycoprotein. In the ER, each glycan signalling structure is recognized by a specific lectin. A domain similar to that of the mannose 6-phosphate receptors (MPRs) has been identified in several proteins of the secretory pathway. These include the beta subunit of glucosidase II (GII), a key enzyme in the early processing of the transferred glycan that removes middle and innermost glucoses and is involved in quality control of glycoprotein folding in the ER (QC), the lectins OS-9 and XTP3-B, proteins involved in the delivery of ER misfolded proteins to degradation (ERAD), the gamma subunit of the Golgi GlcNAc-1-phosphotransferase, an enzyme involved in generating the mannose 6-phosphate (M6P) signal for sorting acidic hydrolases to lysosomes, and finally the MPRs that deliver those hydrolytic enzymes to the lysosome. Each of the MRH-containing proteins recognizes a different signalling N-glycan structure. Three-dimensional structures of some of the MRH domains have been solved, providing the basis to understand recognition mechanisms.
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Affiliation(s)
| | - Nancy M Dahms
- Laboratory of Glycobiology, Fundación Instituto Leloir - Instituto de Investigaciones Bioquimicas de Buenos Aires-CONICET, Av. Patricias Argentinas 435, C1405BWE, Buenos Aires, Argentina, and School of Sciences, University of Buenos Aires, C1428EHA, Buenos Aires, Argentina.
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420
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Dewal MB, DiChiara AS, Antonopoulos A, Taylor RJ, Harmon CJ, Haslam SM, Dell A, Shoulders MD. XBP1s Links the Unfolded Protein Response to the Molecular Architecture of Mature N-Glycans. CHEMISTRY & BIOLOGY 2015; 22:1301-12. [PMID: 26496683 PMCID: PMC4621487 DOI: 10.1016/j.chembiol.2015.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 09/06/2015] [Accepted: 09/09/2015] [Indexed: 12/24/2022]
Abstract
The molecular architecture of the mature N-glycome is dynamic, with consequences for both normal and pathologic processes. Elucidating cellular mechanisms that modulate the N-linked glycome is, therefore, crucial. The unfolded protein response (UPR) is classically responsible for maintaining proteostasis in the secretory pathway by defining levels of chaperones and quality control proteins. Here, we employ chemical biology methods for UPR regulation to show that stress-independent activation of the UPR's XBP1s transcription factor also induces a panel of N-glycan maturation-related enzymes. The downstream consequence is a distinctive shift toward specific hybrid and complex N-glycans on N-glycoproteins produced from XBP1s-activated cells, which we characterize by mass spectrometry. Pulse-chase studies attribute this shift specifically to altered N-glycan processing, rather than to changes in degradation or secretion rates. Our findings implicate XBP1s in a new role for N-glycoprotein biosynthesis, unveiling an important link between intracellular stress responses and the molecular architecture of extracellular N-glycoproteins.
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Affiliation(s)
- Mahender B Dewal
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Andrew S DiChiara
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | | | - Rebecca J Taylor
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Chyleigh J Harmon
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Stuart M Haslam
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Anne Dell
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Matthew D Shoulders
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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421
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Huang LF, Tan CC, Yeh JF, Liu HY, Liu YK, Ho SL, Lu CA. Efficient Secretion of Recombinant Proteins from Rice Suspension-Cultured Cells Modulated by the Choice of Signal Peptide. PLoS One 2015; 10:e0140812. [PMID: 26473722 PMCID: PMC4608814 DOI: 10.1371/journal.pone.0140812] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/29/2015] [Indexed: 11/25/2022] Open
Abstract
Plant-based expression systems have emerged as a competitive platform in the large-scale production of recombinant proteins. By adding a signal peptide, αAmy3sp, the desired recombinant proteins can be secreted outside transgenic rice cells, making them easy to harvest. In this work, to improve the secretion efficiency of recombinant proteins in rice expression systems, various signal peptides including αAmy3sp, CIN1sp, and 33KDsp have been fused to the N-terminus of green fluorescent protein (GFP) and introduced into rice cells to explore the efficiency of secretion of foreign proteins. 33KDsp had better efficiency than αAmy3sp and CIN1sp for the secretion of GFP from calli and suspension-cultured cells. 33KDsp was further applied for the secretion of mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) from transgenic rice suspension-cultured cells; approximately 76%–92% of total rice-derived mGM-CSF (rmGM-CSF) was detected in the culture medium. The rmGM-CSF was bioactive and could stimulate the proliferation of a murine myeloblastic leukemia cell line, NSF-60. The extracellular yield of rmGM-CSF reached 31.7 mg/L. Our study indicates that 33KDsp is better at promoting the secretion of recombinant proteins in rice suspension-cultured cell systems than the commonly used αAmy3sp.
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Affiliation(s)
- Li-Fen Huang
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, 135 Yuan-Tung Road, Taoyuan, Taiwan, ROC
- * E-mail: (L-FH); (C-AL)
| | - Chia-Chun Tan
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, 135 Yuan-Tung Road, Taoyuan, Taiwan, ROC
| | - Ju-Fang Yeh
- Department of Life Science, National Central University, Taoyuan, Taiwan, ROC
| | - Hsin-Yi Liu
- Department of Life Science, National Central University, Taoyuan, Taiwan, ROC
| | - Yu-Kuo Liu
- Graduate Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan, ROC
| | - Shin-Lon Ho
- Department of Agronomy, National Chi-Yi University, Chiayi, Taiwan, ROC
| | - Chung-An Lu
- Department of Life Science, National Central University, Taoyuan, Taiwan, ROC
- * E-mail: (L-FH); (C-AL)
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422
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Xu C, Ng DTW. Glycosylation-directed quality control of protein folding. Nat Rev Mol Cell Biol 2015; 16:742-52. [PMID: 26465718 DOI: 10.1038/nrm4073] [Citation(s) in RCA: 255] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Membrane-bound and soluble proteins of the secretory pathway are commonly glycosylated in the endoplasmic reticulum. These adducts have many biological functions, including, notably, their contribution to the maturation of glycoproteins. N-linked glycans are of oligomeric structure, forming configurations that provide blueprints to precisely instruct the folding of protein substrates and the quality control systems that scrutinize it. O-linked mannoses are simpler in structure and were recently found to have distinct functions in protein quality control that do not require the complex structure of N-linked glycans. Together, recent studies reveal the breadth and sophistication of the roles of these glycan-directed modifications in protein biogenesis.
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Affiliation(s)
- Chengchao Xu
- Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore 117604.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
| | - Davis T W Ng
- Temasek Life Sciences Laboratory, National University of Singapore, 1 Research Link, Singapore 117604.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543.,Duke University-National University of Singapore Graduate Medical School, 8 College Road, Singapore 169857
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423
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Impact of Hybrid and Complex N-Glycans on Cell Surface Targeting of the Endogenous Chloride Cotransporter Slc12a2. Int J Cell Biol 2015; 2015:505294. [PMID: 26351455 PMCID: PMC4553341 DOI: 10.1155/2015/505294] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 06/29/2015] [Accepted: 07/07/2015] [Indexed: 11/21/2022] Open
Abstract
The Na+K+2Cl− cotransporter-1 (Slc12a2, NKCC1) is widely distributed and involved in cell volume/ion regulation. Functional NKCC1 locates in the plasma membrane of all cells studied, particularly in the basolateral membrane of most polarized cells. Although the mechanisms involved in plasma membrane sorting of NKCC1 are poorly understood, it is assumed that N-glycosylation is necessary. Here, we characterize expression, N-glycosylation, and distribution of NKCC1 in COS7 cells. We show that ~25% of NKCC1 is complex N-glycosylated whereas the rest of it corresponds to core/high-mannose and hybrid-type N-glycosylated forms. Further, ~10% of NKCC1 reaches the plasma membrane, mostly as core/high-mannose type, whereas ~90% of NKCC1 is distributed in defined intracellular compartments. In addition, inhibition of the first step of N-glycan biosynthesis with tunicamycin decreases total and plasma membrane located NKCC1 resulting in almost undetectable cotransport function. Moreover, inhibition of N-glycan maturation with swainsonine or kifunensine increased core/hybrid-type NKCC1 expression but eliminated plasma membrane complex N-glycosylated NKCC1 and transport function. Together, these results suggest that (i) NKCC1 is delivered to the plasma membrane of COS7 cells independently of its N-glycan nature, (ii) most of NKCC1 in the plasma membrane is core/hybrid-type N-glycosylated, and (iii) the minimal proportion of complex N-glycosylated NKCC1 is functionally active.
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424
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Importance of asparagine on the conformational stability and chemical reactivity of selected anti-inflammatory peptides. Chem Phys 2015. [DOI: 10.1016/j.chemphys.2015.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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425
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Larrue C, Saland E, Vergez F, Serhan N, Delabesse E, Mansat-De Mas V, Hospital MA, Tamburini J, Manenti S, Sarry JE, Récher C. Antileukemic Activity of 2-Deoxy-d-Glucose through Inhibition of N-Linked Glycosylation in Acute Myeloid Leukemia with FLT3-ITD or c-KIT Mutations. Mol Cancer Ther 2015. [PMID: 26206337 DOI: 10.1158/1535-7163.mct-15-0163] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We assessed the antileukemic activity of 2-deoxy-d-glucose (2-DG) through the modulation of expression of receptor tyrosine kinases (RTK) commonly mutated in acute myeloid leukemia (AML). We used human leukemic cell lines cells, both in vitro and in vivo, as well as leukemic samples from AML patients to demonstrate the role of 2-DG in tumor cell growth inhibition. 2-DG, through N-linked glycosylation inhibition, affected the cell-surface expression and cellular signaling of both FTL3-ITD and mutated c-KIT and induced apoptotic cell death. Leukemic cells harboring these mutated RTKs (MV4-11, MOLM-14, Kasumi-1, and TF-1 c-KIT D816V) were the most sensitive to 2-DG treatment in vitro as compared with nonmutated cells. 2-DG activity was also demonstrated in leukemic cells harboring FLT3-TKD mutations resistant to the tyrosine kinase inhibitor (TKI) quizartinib. Moreover, the antileukemic activity of 2-DG was particularly marked in c-KIT-mutated cell lines and cell samples from core binding factor-AML patients. In these cells, 2-DG inhibited the cell-surface expression of c-KIT, abrogated STAT3 and MAPK-ERK pathways, and strongly downregulated the expression of the receptor resulting in a strong in vivo effect in NOD/SCID mice xenografted with Kasumi-1 cells. Finally, we showed that 2-DG decreases Mcl-1 protein expression in AML cells and induces sensitization to both the BH3 mimetic inhibitor of Bcl-xL, Bcl-2 and Bcl-w, ABT-737, and cytarabine. In conclusion, 2-DG displays a significant antileukemic activity in AML with FLT3-ITD or KIT mutations, opening a new therapeutic window in a subset of AML with mutated RTKs.
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Affiliation(s)
- Clément Larrue
- Cancer Research Center of Toulouse (CRCT), UMR1037 INSERM, ERL5294 CNRS, Toulouse, France. Université Toulouse III Paul Sabatier, Toulouse, France
| | - Estelle Saland
- Cancer Research Center of Toulouse (CRCT), UMR1037 INSERM, ERL5294 CNRS, Toulouse, France. Université Toulouse III Paul Sabatier, Toulouse, France
| | - François Vergez
- Cancer Research Center of Toulouse (CRCT), UMR1037 INSERM, ERL5294 CNRS, Toulouse, France. Université Toulouse III Paul Sabatier, Toulouse, France. Laboratoire d'Hématologie, Institut Universitaire du Cancer de Toulouse Oncopole, Toulouse, France
| | - Nizar Serhan
- Cancer Research Center of Toulouse (CRCT), UMR1037 INSERM, ERL5294 CNRS, Toulouse, France. Université Toulouse III Paul Sabatier, Toulouse, France
| | - Eric Delabesse
- Cancer Research Center of Toulouse (CRCT), UMR1037 INSERM, ERL5294 CNRS, Toulouse, France. Université Toulouse III Paul Sabatier, Toulouse, France. Laboratoire d'Hématologie, Institut Universitaire du Cancer de Toulouse Oncopole, Toulouse, France
| | - Véronique Mansat-De Mas
- Cancer Research Center of Toulouse (CRCT), UMR1037 INSERM, ERL5294 CNRS, Toulouse, France. Université Toulouse III Paul Sabatier, Toulouse, France. Laboratoire d'Hématologie, Institut Universitaire du Cancer de Toulouse Oncopole, Toulouse, France
| | - Marie-Anne Hospital
- Institut Cochin, Département Développement, Reproduction, Cancer, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8104, Institut National de la Santé et de la Recherche Médicale (INSERM) U1016, Paris, France. Université Paris Descartes, Faculté de Médecine Sorbonne Paris Cité, Paris, France
| | - Jérôme Tamburini
- Institut Cochin, Département Développement, Reproduction, Cancer, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8104, Institut National de la Santé et de la Recherche Médicale (INSERM) U1016, Paris, France. Université Paris Descartes, Faculté de Médecine Sorbonne Paris Cité, Paris, France
| | - Stéphane Manenti
- Cancer Research Center of Toulouse (CRCT), UMR1037 INSERM, ERL5294 CNRS, Toulouse, France. Université Toulouse III Paul Sabatier, Toulouse, France
| | - Jean Emmanuel Sarry
- Cancer Research Center of Toulouse (CRCT), UMR1037 INSERM, ERL5294 CNRS, Toulouse, France. Université Toulouse III Paul Sabatier, Toulouse, France
| | - Christian Récher
- Cancer Research Center of Toulouse (CRCT), UMR1037 INSERM, ERL5294 CNRS, Toulouse, France. Université Toulouse III Paul Sabatier, Toulouse, France. Service d'Hématologie, Institut Universitaire du Cancer de Toulouse Oncopole, Toulouse, France.
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426
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Harada Y, Masahara-Negishi Y, Suzuki T. Cytosolic-free oligosaccharides are predominantly generated by the degradation of dolichol-linked oligosaccharides in mammalian cells. Glycobiology 2015. [DOI: 10.1093/glycob/cwv055] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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427
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Abstract
INTRODUCTION Glycans are increasingly important in the development of new biopharmaceuticals with optimized efficacy, half-life, and antigenicity. Current expression platforms for recombinant glycoprotein therapeutics typically do not produce homogeneous glycans and frequently display non-human glycans which may cause unwanted side effects. To circumvent these issues, glyco-engineering has been applied to different expression systems including mammalian cells, insect cells, yeast, and plants. AREAS COVERED This review summarizes recent developments in glyco-engineering focusing mainly on in vivo expression systems for recombinant proteins. The highlighted strategies aim at producing glycoproteins with homogeneous N- and O-linked glycans of defined composition. EXPERT OPINION Glyco-engineering of expression platforms is increasingly recognized as an important strategy to improve biopharmaceuticals. A better understanding and control of the factors leading to glycan heterogeneity will allow simplified production of recombinant glycoprotein therapeutics with less variation in terms of glycosylation. Further technological advances will have a major impact on manufacturing processes and may provide a completely new class of glycoprotein therapeutics with customized functions.
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Affiliation(s)
- Martina Dicker
- a 1 University of Natural Resources and Life Sciences , Department of Applied Genetics and Cell Biology , Muthgasse 18, Vienna, Austria
| | - Richard Strasser
- b 2 University of Natural Resources and Life Sciences, Department of Applied Genetics and Cell Biology , Muthgasse 18, Vienna, Austria +43 1 47654 6705 ; +43 1 47654 6392 ;
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428
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Harada Y, Hirayama H, Suzuki T. Generation and degradation of free asparagine-linked glycans. Cell Mol Life Sci 2015; 72:2509-33. [PMID: 25772500 PMCID: PMC11113800 DOI: 10.1007/s00018-015-1881-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 02/19/2015] [Accepted: 03/05/2015] [Indexed: 10/23/2022]
Abstract
Asparagine (N)-linked protein glycosylation, which takes place in the eukaryotic endoplasmic reticulum (ER), is important for protein folding, quality control and the intracellular trafficking of secretory and membrane proteins. It is known that, during N-glycosylation, considerable amounts of lipid-linked oligosaccharides (LLOs), the glycan donor substrates for N-glycosylation, are hydrolyzed to form free N-glycans (FNGs) by unidentified mechanisms. FNGs are also generated in the cytosol by the enzymatic deglycosylation of misfolded glycoproteins during ER-associated degradation. FNGs derived from LLOs and misfolded glycoproteins are eventually merged into one pool in the cytosol and the various glycan structures are processed to a near homogenous glycoform. This article summarizes the current state of our knowledge concerning the formation and catabolism of FNGs.
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Affiliation(s)
- Yoichiro Harada
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan
| | - Hiroto Hirayama
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan
| | - Tadashi Suzuki
- Glycometabolome Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan
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429
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Olson LJ, Orsi R, Peterson FC, Parodi AJ, Kim JJP, D'Alessio C, Dahms NM. Crystal Structure and Functional Analyses of the Lectin Domain of Glucosidase II: Insights into Oligomannose Recognition. Biochemistry 2015; 54:4097-111. [PMID: 26062005 DOI: 10.1021/acs.biochem.5b00256] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
N-Glycans are modified as part of a quality control mechanism during glycoprotein folding in the endoplasmic reticulum (ER). Glucosidase II (GII) plays a critical role by generating monoglucosylated glycans that are recognized by lectin chaperones, calnexin and calreticulin. To understand how the hydrolytic activity of GIIα is enhanced by the mannose 6-phosphate receptor (MPR) homology domain (MRH domain) of its β subunit, we now report a 1.6 Å resolution crystal structure of the MRH domain of GIIβ bound to mannose. A comparison of ligand-bound and unbound structures reveals no major difference in their overall fold, but rather a repositioning of side chains throughout the binding pocket, including Y372. Mutation of Y372 inhibits GII activity, demonstrating an important role for Y372 in regulating GII activity. Comparison of the MRH domains of GIIβ, MPRs, and the ER lectin OS-9 identified conserved residues that are critical for the structural integrity and architecture of the carbohydrate binding pocket. As shown by nuclear magnetic resonance spectroscopy, mutations of the primary binding pocket residues and adjacent W409, all of which inhibit the activity of GII both in vitro and in vivo, do not cause a significant change in the overall fold of the GIIβ MRH domain but impact locally the stability of the binding pocket. W409 does not directly contact mannose; rather, its indole ring is stabilized by binding into a hydrophobic pocket of an adjacent crystallographic neighbor. This suggests that W409 interacts with a hydrophobic region of the GIIβ or GIIα subunit to modulate its effect on GII activity.
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Affiliation(s)
- Linda J Olson
- †Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
| | - Ramiro Orsi
- ‡Laboratory of Glycobiology, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Francis C Peterson
- †Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
| | - Armando J Parodi
- ‡Laboratory of Glycobiology, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Jung-Ja P Kim
- †Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
| | - Cecilia D'Alessio
- ‡Laboratory of Glycobiology, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires-CONICET, Buenos Aires, Argentina.,§School of Sciences, University of Buenos Aires, Buenos Aires, Argentina
| | - Nancy M Dahms
- †Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
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430
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Zhu Z, Desaire H. Carbohydrates on Proteins: Site-Specific Glycosylation Analysis by Mass Spectrometry. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2015; 8:463-483. [PMID: 26070719 DOI: 10.1146/annurev-anchem-071114-040240] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Glycosylation on proteins adds complexity and versatility to these biologically vital macromolecules. To unveil the structure-function relationship of glycoproteins, glycopeptide-centric analysis using mass spectrometry (MS) has become a method of choice because the glycan is preserved on the glycosylation site and site-specific glycosylation profiles of proteins can be readily determined. However, glycopeptide analysis is still challenging given that glycopeptides are usually low in abundance and relatively difficult to detect and the resulting data require expertise to analyze. Viewing the urgent need to address these challenges, emerging methods and techniques are being developed with the goal of analyzing glycopeptides in a sensitive, comprehensive, and high-throughput manner. In this review, we discuss recent advances in glycoprotein and glycopeptide analysis, with topics covering sample preparation, analytical separation, MS and tandem MS techniques, as well as data interpretation and automation.
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Affiliation(s)
- Zhikai Zhu
- Ralph N. Adams Institute for Bioanalytical Chemistry, Department of Chemistry, University of Kansas, Lawrence, Kansas 66047;
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431
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Corfield AP, Berry M. Glycan variation and evolution in the eukaryotes. Trends Biochem Sci 2015; 40:351-9. [PMID: 26002999 DOI: 10.1016/j.tibs.2015.04.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 04/16/2015] [Accepted: 04/27/2015] [Indexed: 11/18/2022]
Abstract
In this review, we document the evolution of common glycan structures in the eukaryotes, and illustrate the considerable variety of oligosaccharides existing in these organisms. We focus on the families of N- and O-glycans, glycosphingolipids, glycosaminoglycans, glycosylphosphatidylinositol (GPI) anchors, sialic acids (Sias), and cytoplasmic and nuclear glycans. We also outline similar and divergent aspects of the glycans during evolution within the groups, which include inter- and intraspecies differences, molecular mimicry, viral glycosylation adaptations, glycosyltransferase specificity relating to function, and the natural dynamism powering these events. Finally, we present an overview of the patterns of glycosylation found within the groups comprising the Eukaryota, namely the Deuterostomia, Fungi, Viridiplantae, Nematoda, and Arthropoda.
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Affiliation(s)
- Anthony P Corfield
- Mucin Research Group, University of Bristol, School of Clinical Sciences, Bristol Royal Infirmary, Bristol, BS2 8HW, UK.
| | - Monica Berry
- University of Bristol, School of Physics, Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol, BS8 1FD, UK.
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432
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Hirayama H, Hosomi A, Suzuki T. Physiological and molecular functions of the cytosolic peptide:N-glycanase. Semin Cell Dev Biol 2015; 41:110-20. [DOI: 10.1016/j.semcdb.2014.11.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 01/04/2023]
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433
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Lindner H, Kessler SA, Müller LM, Shimosato-Asano H, Boisson-Dernier A, Grossniklaus U. TURAN and EVAN mediate pollen tube reception in Arabidopsis Synergids through protein glycosylation. PLoS Biol 2015; 13:e1002139. [PMID: 25919390 PMCID: PMC4412406 DOI: 10.1371/journal.pbio.1002139] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/19/2015] [Indexed: 11/18/2022] Open
Abstract
Pollen tube (PT) reception in flowering plants describes the crosstalk between the male and female gametophytes upon PT arrival at the synergid cells of the ovule. It leads to PT growth arrest, rupture, and sperm cell release, and is thus essential to ensure double fertilization. Here, we describe TURAN (TUN) and EVAN (EVN), two novel members of the PT reception pathway that is mediated by the FERONIA (FER) receptor-like kinase (RLK). Like fer, mutations in these two genes lead to PT overgrowth inside the female gametophyte (FG) without PT rupture. Mapping by next-generation sequencing, cytological analysis of reporter genes, and biochemical assays of glycoproteins in RNAi knockdown mutants revealed both genes to be involved in protein N-glycosylation in the endoplasmic reticulum (ER). TUN encodes a uridine diphosphate (UDP)-glycosyltransferase superfamily protein and EVN a dolichol kinase. In addition to their common role during PT reception in the synergids, both genes have distinct functions in the pollen: whereas EVN is essential for pollen development, TUN is required for PT growth and integrity by affecting the stability of the pollen-specific FER homologs ANXUR1 (ANX1) and ANX2. ANX1- and ANX2-YFP reporters are not expressed in tun pollen grains, but ANX1-YFP is degraded via the ER-associated degradation (ERAD) pathway, likely underlying the anx1/2-like premature PT rupture phenotype of tun mutants. Thus, as in animal sperm–egg interactions, protein glycosylation is essential for the interaction between the female and male gametophytes during PT reception to ensure fertilization and successful reproduction. Protein glycosylation is essential for gametophyte interactions between the male pollen tube and the female ovule in plants, reminiscent of gamete interactions during fertilization in mammals. In flowering plants, gametes are produced by the haploid, multicellular male (pollen), and female (embryo sac) gametophytes, which develop within the reproductive organs of the flower. Successful fertilization depends on delivery of the sperm cells to the embryo sac, which is embedded in the ovule, by the pollen tube. Upon arrival of the pollen tube at the opening of the ovule, crosstalk between male and female gametophytes, known as pollen tube reception, ensues; the pollen tube slows or stops its growth, then resumes rapid growth, and finally bursts to release the sperm cells and effect double fertilization. Although several members of the pollen tube reception pathway, including the receptor-like kinase FERONIA, have been identified, the molecular mechanisms underlying this communication process remain unclear. Here, we show that protein N-glycosylation is required for normal pollen tube reception. A mutant screen identified two genes, TURAN and EVAN, which are involved in protein N-glycosylation in the endoplasmic reticulum. Both genes act in the FERONIA-mediated pollen tube reception pathway, which is impaired in these mutants. Thus, in plants, a “dual recognition system,” involving interactions between both protein and glycosyl residues on the surface of male and female gametophytes, appears to be required for successful pollen tube reception, conceptually similar to sperm–egg interactions in mammals, for which N-glycosylation of cell surface proteins also plays an important role.
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Affiliation(s)
- Heike Lindner
- Institute of Plant Biology & Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zürich, Switzerland
| | - Sharon A. Kessler
- Institute of Plant Biology & Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zürich, Switzerland
| | - Lena M. Müller
- Institute of Plant Biology & Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zürich, Switzerland
| | - Hiroko Shimosato-Asano
- Institute of Plant Biology & Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zürich, Switzerland
| | - Aurélien Boisson-Dernier
- Institute of Plant Biology & Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zürich, Switzerland
| | - Ueli Grossniklaus
- Institute of Plant Biology & Zurich-Basel Plant Science Center, University of Zurich, CH-8008 Zürich, Switzerland
- * E-mail:
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434
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Shrimal S, Gilmore R. Reduced expression of the oligosaccharyltransferase exacerbates protein hypoglycosylation in cells lacking the fully assembled oligosaccharide donor. Glycobiology 2015; 25:774-83. [PMID: 25792706 DOI: 10.1093/glycob/cwv018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/09/2015] [Indexed: 11/13/2022] Open
Abstract
A defect in the assembly of the oligosaccharide donor (Dol-PP-GlcNAc(2)Man(9)Glc(3)) for N-linked glycosylation causes hypoglycosylation of proteins by the oligosaccharyltransferase (OST). Mammalian cells express two OST complexes that have different catalytic subunits (STT3A or STT3B). We monitored glycosylation of proteins in asparagine-linked glycosylation 6 (ALG6) deficient cell lines that assemble Dol-PP-GlcNAc(2)Man(9) as the largest oligosaccharide donor. Based upon pulse labeling experiments, 30-40% of STT3A-dependent glycosylation sites and 20% of STT3B-dependent sites are skipped in ALG6-congenital disorders of glycosylation fibroblasts supporting previous evidence that the STT3B complex has a relaxed preference for the fully assembled oligosaccharide donor. Glycosylation of STT3B-dependent sites was more severely reduced in the ALG6 deficient MI8-5 cell line. Protein immunoblot analysis and RT-PCR revealed that MI8-5 cells express 2-fold lower levels of STT3B than the parental Chinese hamster ovary cells. The combination of reduced expression of STT3B and the lack of the optimal Dol-PP-GlcNAc(2)Man(9)Glc(3) donor synergize to cause very severe hypoglycosylation of proteins in MI8-5 cells. Thus, differences in OST subunit expression can modify the severity of hypoglycosylation displayed by cells with a primary defect in the dolichol oligosaccharide assembly pathway.
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Affiliation(s)
- Shiteshu Shrimal
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Reid Gilmore
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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435
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Lectins from opportunistic bacteria interact with acquired variable-region glycans of surface immunoglobulin in follicular lymphoma. Blood 2015; 125:3287-96. [PMID: 25784678 DOI: 10.1182/blood-2014-11-609404] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/10/2015] [Indexed: 12/13/2022] Open
Abstract
B-cell antigen receptor (BCR) expression is a key feature of most B-cell lymphomas, but the mechanisms of BCR signal induction and the involvement of autoantigen recognition remain unclear. In follicular lymphoma (FL) B cells, BCR expression is retained despite a chromosomal translocation that links the antiapoptotic gene BCL2 to the regulatory elements of immunoglobulin genes, thereby disrupting 1 heavy-chain allele. A remarkable feature of FL-BCRs is the acquisition of potential N-glycosylation sites during somatic hypermutation. The introduced glycans carry mannose termini, which create potential novel binding sites for mannose-specific lectins. Here, we investigated the effect of N-linked variable-region glycosylation for BCR interaction with cognate antigen and with lectins of different origins. N-glycans were found to severely impair BCR specificity and affinity to the initial cognate antigen. In addition, we found that lectins from Pseudomonas aeruginosa and Burkholderia cenocepacia bind and stimulate FL cells. Human exposure to these bacteria can occur by contact with soil and water. In addition, they represent opportunistic pathogens in susceptible hosts. Understanding the role of bacterial lectins might elucidate the pathogenesis of FL and establish novel therapeutic approaches.
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436
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Quo vadis? The challenges of recombinant protein folding and secretion in Pichia pastoris. Appl Microbiol Biotechnol 2015; 99:2925-38. [DOI: 10.1007/s00253-015-6470-z] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Revised: 02/05/2015] [Accepted: 02/08/2015] [Indexed: 10/23/2022]
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437
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A context-independent N-glycan signal targets the misfolded extracellular domain of Arabidopsis STRUBBELIG to endoplasmic-reticulum-associated degradation. Biochem J 2015; 464:401-11. [PMID: 25251695 PMCID: PMC4255730 DOI: 10.1042/bj20141057] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
N-glycosylation of proteins plays an important role in the determination of the fate of newly synthesized glycoproteins in the endoplasmic reticulum (ER). Specific oligosaccharide structures recruit molecular chaperones that promote folding or mannose-binding lectins that assist in the clearance of improperly-folded glycoproteins by delivery to ER-associated degradation (ERAD). In plants, the mechanisms and factors that recognize non-native proteins and sort them to ERAD are poorly understood. In the present study, we provide evidence that a misfolded variant of the STRUBBELIG (SUB) extracellular domain (SUBEX-C57Y) is degraded in a glycan-dependent manner in plants. SUBEX-C57Y is an ER-retained glycoprotein with three N-glycans that is stabilized in the presence of kifunensine, a potent inhibitor of α-mannosidases. Stable expression in Arabidopsis thaliana knockout mutants revealed that SUBEX-C57Y degradation is dependent on the ER lectin OS9 and its associated ERAD factor SEL1L. SUBEX-C57Y was also stabilized in plants lacking the α-mannosidases MNS4 and MNS5 that generate a terminal α1,6-linked mannose on the C-branch of N-glycans. Notably, the glycan signal for degradation is not constrained to a specific position within SUBEX-C57Y. Structural analysis revealed that SUBEX-C57Y harbours considerable amounts of Glc1Man7GlcNAc2 N-glycans suggesting that the ER-quality control processes involving calnexin/calreticulin (CNX/CRT) and ERAD are tightly interconnected to promote protein folding or disposal by termination of futile folding attempts.
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438
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Ding Y, Uchida K, Aizawa SI, Murphy K, Berezuk A, Khursigara CM, Chong JPJ, Jarrell KF. Effects of N-glycosylation site removal in archaellins on the assembly and function of archaella in Methanococcus maripaludis. PLoS One 2015; 10:e0116402. [PMID: 25700084 PMCID: PMC4336324 DOI: 10.1371/journal.pone.0116402] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 12/09/2014] [Indexed: 12/22/2022] Open
Abstract
In Methanococcus maripaludis S2, the swimming organelle, the archaellum, is composed of three archaellins, FlaB1S2, FlaB2S2 and FlaB3S2. All three are modified with an N-linked tetrasaccharide at multiple sites. Disruption of the N-linked glycosylation pathway is known to cause defects in archaella assembly or function. Here, we explored the potential requirement of N-glycosylation of archaellins on archaellation by investigating the effects of eliminating the 4 N-glycosylation sites in the wildtype FlaB2S2 protein in all possible combinations either by Asn to Glu (N to Q) substitution or Asn to Asp (N to D) substitutions of the N-glycosylation sequon asparagine. The ability of these mutant derivatives to complement a non-archaellated ΔflaB2S2 strain was examined by electron microscopy (for archaella assembly) and swarm plates (for analysis of swimming). Western blot results showed that all mutated FlaB2S2 proteins were expressed and of smaller apparent molecular mass compared to wildtype FlaB2S2, consistent with the loss of glycosylation sites. In the 8 single-site mutant complements, archaella were observed on the surface of Q2, D2 and D4 (numbers after N or Q refer to the 1st to 4th glycosylation site). Of the 6 double-site mutation complementations all were archaellated except D1,3. Of the 4 triple-site mutation complements, only D2,3,4 was archaellated. Elimination of all 4 N-glycosylation sites resulted in non-archaellated cells, indicating some minimum amount of archaellin glycosylation was necessary for their incorporation into stable archaella. All complementations that led to a return of archaella also resulted in motile cells with the exception of the D4 version. In addition, a series of FlaB2S2 scanning deletions each missing 10 amino acids was also generated and tested for their ability to complement the ΔflaB2S2 strain. While most variants were expressed, none of them restored archaellation, although FlaB2S2 harbouring a smaller 3-amino acid deletion was able to partially restore archaellation.
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Affiliation(s)
- Yan Ding
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Kaoru Uchida
- Department of Life Sciences, Prefectural University of Hiroshima, 562 Nanatsuka, Shobara, Hiroshima, Japan
| | - Shin-Ichi Aizawa
- Department of Life Sciences, Prefectural University of Hiroshima, 562 Nanatsuka, Shobara, Hiroshima, Japan
| | - Kathleen Murphy
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Alison Berezuk
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Cezar M. Khursigara
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - James P. J. Chong
- Department of Biology, University of York, Heslington, York, United Kingdom
| | - Ken F. Jarrell
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
- * E-mail:
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439
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Bochud A, Conzelmann A. The active site of yeast phosphatidylinositol synthase Pis1 is facing the cytosol. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:629-40. [PMID: 25687304 DOI: 10.1016/j.bbalip.2015.02.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/30/2015] [Accepted: 02/06/2015] [Indexed: 02/01/2023]
Abstract
Five yeast enzymes synthesizing various glycerophospholipids belong to the CDP-alcohol phosphatidyltransferase (CAPT) superfamily. They only share the so-called CAPT motif, which forms the active site of all these enzymes. Bioinformatic tools predict the CAPT motif of phosphatidylinositol synthase Pis1 as either ER luminal or cytosolic. To investigate the membrane topology of Pis1, unique cysteine residues were introduced into either native or a Cys-free form of Pis1 and their accessibility to the small, membrane permeating alkylating reagent N-ethylmaleimide (NEM) and mass tagged, non-permeating maleimides, in the presence and absence of non-denaturing detergents, was monitored. The results clearly point to a cytosolic location of the CAPT motif. Pis1 is highly sensitive to non-denaturing detergent, and low concentrations (0.05%) of dodecylmaltoside change the accessibility of single substituted Cys in the active site of an otherwise cysteine free version of Pis1. Slightly higher detergent concentrations inactivate the enzyme. Removal of the ER retrieval sequence from (wt) Pis1 enhances its activity, again suggesting an influence of the lipid environment. The central 84% of the Pis1 sequence can be aligned and fitted onto the 6 transmembrane helices of two recently crystallized archaeal members of the CAPT family. Results delineate the accessibility of different parts of Pis1 in their natural context and allow to critically evaluate the performance of different cysteine accessibility methods. Overall the results show that cytosolically made inositol and CDP-diacylglycerol can access the active site of the yeast PI synthase Pis1 from the cytosolic side and that Pis1 structure is strongly affected by mild detergents.
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Affiliation(s)
- Arlette Bochud
- Department of Biology, University of Fribourg, Switzerland
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440
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The dimeric crystal structure of the human fertility lipocalin glycodelin reveals a protein scaffold for the presentation of complex glycans. Biochem J 2015; 466:95-104. [DOI: 10.1042/bj20141003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Structural study of human glycodelin, which is involved in reproduction, reveals a homodimeric structure ideally suited as scaffold for the presentation of distinct glycans, whereas bioinformatic analysis indicated exclusive occurrence in suborders of primates that have a menstrual cycle.
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441
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Thaysen-Andersen M, Venkatakrishnan V, Loke I, Laurini C, Diestel S, Parker BL, Packer NH. Human neutrophils secrete bioactive paucimannosidic proteins from azurophilic granules into pathogen-infected sputum. J Biol Chem 2015; 290:8789-802. [PMID: 25645918 DOI: 10.1074/jbc.m114.631622] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Indexed: 01/09/2023] Open
Abstract
Unlike plants and invertebrates, mammals reportedly lack proteins displaying asparagine (N)-linked paucimannosylation (mannose(1-3)fucose(0-1)N-acetylglucosamine(2)Asn). Enabled by technology advancements in system-wide biomolecular characterization, we document that protein paucimannosylation is a significant host-derived molecular signature of neutrophil-rich sputum from pathogen-infected human lungs and is negligible in pathogen-free sputum. Five types of paucimannosidic N-glycans were carried by compartment-specific and inflammation-associated proteins of the azurophilic granules of human neutrophils including myeloperoxidase (MPO), azurocidin, and neutrophil elastase. The timely expressed human azurophilic granule-resident β-hexosaminidase A displayed the capacity to generate paucimannosidic N-glycans by trimming hybrid/complex type N-glycan intermediates with relative broad substrate specificity. Paucimannosidic N-glycoepitopes showed significant co-localization with β-hexosaminidase A and the azurophilic marker MPO in human neutrophils using immunocytochemistry. Furthermore, promyelocyte stage-specific expression of genes coding for paucimannosidic proteins and biosynthetic enzymes indicated a novel spatio-temporal biosynthetic route in early neutrophil maturation. The absence of bacterial exoglycosidase activities and paucimannosidic N-glycans excluded exogenous origins of paucimannosylation. Paucimannosidic proteins from isolated and sputum neutrophils were preferentially secreted upon inoculation with virulent Pseudomonas aeruginosa. Finally, paucimannosidic proteins displayed affinities to mannose-binding lectin, suggesting immune-related functions of paucimannosylation in activated human neutrophils. In conclusion, we are the first to document that human neutrophils produce, store and, upon activation, selectively secrete bioactive paucimannosidic proteins into sputum of lungs undergoing pathogen-based inflammation.
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Affiliation(s)
- Morten Thaysen-Andersen
- From the Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales-2109, Australia,
| | - Vignesh Venkatakrishnan
- From the Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales-2109, Australia
| | - Ian Loke
- From the Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales-2109, Australia
| | - Christine Laurini
- the Institute of Nutrition and Food Sciences, University of Bonn, Bonn 53113, Germany, and
| | - Simone Diestel
- the Institute of Nutrition and Food Sciences, University of Bonn, Bonn 53113, Germany, and
| | - Benjamin L Parker
- the Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales-2010, Australia
| | - Nicolle H Packer
- From the Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales-2109, Australia
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442
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Hamorsky KT, Kouokam JC, Jurkiewicz JM, Nelson B, Moore LJ, Husk AS, Kajiura H, Fujiyama K, Matoba N. N-glycosylation of cholera toxin B subunit in Nicotiana benthamiana: impacts on host stress response, production yield and vaccine potential. Sci Rep 2015; 5:8003. [PMID: 25614217 PMCID: PMC4303877 DOI: 10.1038/srep08003] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 12/16/2014] [Indexed: 01/01/2023] Open
Abstract
Plant-based transient overexpression systems enable rapid and scalable production of subunit vaccines. Previously, we have shown that cholera toxin B subunit (CTB), an oral cholera vaccine antigen, is N-glycosylated upon expression in transgenic Nicotiana benthamiana. Here, we found that overexpression of aglycosylated CTB by agroinfiltration of a tobamoviral vector causes massive tissue necrosis and poor accumulation unless retained in the endoplasmic reticulum (ER). However, the re-introduction of N-glycosylation to its original or an alternative site significantly relieved the necrosis and provided a high CTB yield without ER retention. Quantitative gene expression analysis of PDI, BiP, bZIP60, SKP1, 26Sα proteasome and PR1a, and the detection of ubiquitinated CTB polypeptides revealed that N-glycosylation significantly relieved ER stress and hypersensitive response, and facilitated the folding/assembly of CTB. The glycosylated CTB (gCTB) was characterized for potential vaccine use. Glycan profiling revealed that gCTB contained approximately 38% plant-specific glycans. gCTB retained nanomolar affinity to GM1-ganglioside with only marginal reduction of physicochemical stability and induced an anti-cholera holotoxin antibody response comparable to native CTB in a mouse oral immunization study. These findings demonstrated gCTB's potential as an oral immunogen and point to a potential role of N-glycosylation in increasing recombinant protein yields in plants.
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Affiliation(s)
- Krystal Teasley Hamorsky
- 1] Owensboro Cancer Research Program of James Graham Brown Cancer Center at University of Louisville School of Medicine, Owensboro, KY, USA [2] Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA
| | - J Calvin Kouokam
- 1] Owensboro Cancer Research Program of James Graham Brown Cancer Center at University of Louisville School of Medicine, Owensboro, KY, USA [2] Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA
| | - Jessica M Jurkiewicz
- Owensboro Cancer Research Program of James Graham Brown Cancer Center at University of Louisville School of Medicine, Owensboro, KY, USA
| | - Bailey Nelson
- Owensboro Cancer Research Program of James Graham Brown Cancer Center at University of Louisville School of Medicine, Owensboro, KY, USA
| | - Lauren J Moore
- Owensboro Cancer Research Program of James Graham Brown Cancer Center at University of Louisville School of Medicine, Owensboro, KY, USA
| | - Adam S Husk
- Owensboro Cancer Research Program of James Graham Brown Cancer Center at University of Louisville School of Medicine, Owensboro, KY, USA
| | - Hiroyuki Kajiura
- The International Center for Biotechnology, Osaka University, Osaka, Japan
| | - Kazuhito Fujiyama
- The International Center for Biotechnology, Osaka University, Osaka, Japan
| | - Nobuyuki Matoba
- 1] Owensboro Cancer Research Program of James Graham Brown Cancer Center at University of Louisville School of Medicine, Owensboro, KY, USA [2] Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA
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443
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Seiradake E, Zhao Y, Lu W, Aricescu AR, Jones EY. Production of cell surface and secreted glycoproteins in mammalian cells. Methods Mol Biol 2015; 1261:115-27. [PMID: 25502196 DOI: 10.1007/978-1-4939-2230-7_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Mammalian protein expression systems are becoming increasingly popular for the production of eukaryotic secreted and cell surface proteins. Here we describe methods to produce recombinant proteins in adherent or suspension human embryonic kidney cell cultures, using transient transfection or stable cell lines. The protocols are easy to scale up and cost-efficient, making them suitable for protein crystallization projects and other applications that require high protein yields.
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Affiliation(s)
- Elena Seiradake
- The Division of Structural Biology, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford, OX3 7BN, UK
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444
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Abstract
N-linked glycosylation is one of the most prevalent cotranslational protein modifications in plants. It is initiated by a conserved process in the endoplasmic reticulum and subsequently involves a series of different N-glycan maturation steps that take place in the ER and Golgi apparatus. Despite our vast knowledge on the different processing steps we still understand very little about the role of characteristic glycoforms present on individual plant glycoproteins. Here, we describe convenient tools that allow the fast and reliable characterization of N-glycosylation on plant glycoproteins. The presented protocols can be adopted to other plant species and to the characterization of N-glycans from different glycoproteins.
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445
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Buczkowska A, Swiezewska E, Lefeber DJ. Genetic defects in dolichol metabolism. J Inherit Metab Dis 2015; 38:157-69. [PMID: 25270028 PMCID: PMC4281381 DOI: 10.1007/s10545-014-9760-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/25/2014] [Accepted: 08/01/2014] [Indexed: 11/27/2022]
Abstract
Congenital disorders of glycosylation (CDG) comprise a group of inborn errors of metabolism with abnormal glycosylation of proteins and lipids. Patients with defective protein N-glycosylation are identified in routine metabolic screening via analysis of serum transferrin glycosylation. Defects in the assembly of the dolichol linked Glc(3)Man(9)GlcNAc(2) glycan and its transfer to proteins lead to the (partial) absence of complete glycans on proteins. These defects are called CDG-I and are located in the endoplasmic reticulum (ER) or cytoplasm. Defects in the subsequent processing of protein bound glycans result in the presence of truncated glycans on proteins. These defects are called CDG-II and the enzymes involved are located mainly in the Golgi apparatus. In recent years, human defects have been identified in dolichol biosynthesis genes within the group of CDG-I patients. This has increased interest in dolichol metabolism, has resulted in specific recognizable clinical symptoms in CDG-I and has offered new mechanistic insights in dolichol biosynthesis. We here review its biosynthetic pathways, the clinical and biochemical phenotypes in dolichol-related CDG defects, up to the formation of dolichyl-P-mannose (Dol-P-Man), and discuss existing evidence of regulatory networks in dolichol metabolism to provide an outlook on therapeutic strategies.
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Affiliation(s)
- Anna Buczkowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Department of Lipid Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Dirk J. Lefeber
- Department of Neurology, Laboratory of Genetic, Endocrine and Metabolic Diseases, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands
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446
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Guo H, Abbott KL. Functional impact of tumor-specific N-linked glycan changes in breast and ovarian cancers. Adv Cancer Res 2015; 126:281-303. [PMID: 25727151 DOI: 10.1016/bs.acr.2014.11.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Changes in glycosylation have been implicated in various human diseases, including cancer. Research over the past few decades has produced significant findings that illustrate the importance of cancer-specific alterations in glycosylation in the regulation of tumor formation and metastasis. The identification of glycan-based biomarkers and strategies targeting specific glycan epitopes on the tumor cell surface has become one of the widely pursued research areas. In this chapter, we will summarize and provide perspective on available knowledge about the functional roles that glycan structures play in the development and progression of the gynecological cancers, breast and ovarian, with a specific focus on N-linked glycans. A better understanding of the functional roles for glycans in cancer will drive future innovations for diagnostics and therapeutics.
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447
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Abstract
While yeast are lower eukaryotic organisms, they share many common features and biological processes with higher eukaryotes. As such, yeasts have been used as model organisms to facilitate our understanding of such features and processes. To this end, a large number of powerful genetic tools have been developed to investigate and manipulate these organisms. Going hand-in-hand with these genetic tools is the ability to efficiently scale up the fermentation of these organisms, thus making them attractive hosts for the production of recombinant proteins. A key feature of producing recombinant proteins in yeast is that these proteins can be readily secreted into the culture supernatant, simplifying any downstream processing. A consequence of this secretion is that the proteins typically pass through the secretory pathway, during which they may be exposed to various posttranslational modifications. The addition of glycans is one such modification. Unfortunately, while certain aspects of glycosylation are shared between lower and higher eukaryotes, significant differences exist. Over the last two decades much research has focused on engineering the glycosylation pathways of yeast to more closely resemble those of higher eukaryotes, particularly those of humans for the production of therapeutic proteins. In the current review we shall highlight some of the key achievements in yeast glyco-engineering which have led to humanization of both the N- and O-linked glycosylation pathways.
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448
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Barb AW. Intramolecular N-glycan/polypeptide interactions observed at multiple N-glycan remodeling steps through [(13)C,(15)N]-N-acetylglucosamine labeling of immunoglobulin G1. Biochemistry 2014; 54:313-22. [PMID: 25551295 PMCID: PMC4302832 DOI: 10.1021/bi501380t] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
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Asparagine-linked (N) glycosylation
is a common eukaryotic protein
modification that affects protein folding, function, and stability
through intramolecular interactions between N-glycan
and polypeptide residues. Attempts to characterize the structure–activity
relationship of each N-glycan are hindered by inherent
properties of the glycoprotein, including glycan conformational and
compositional heterogeneity. These limitations can be addressed by
using a combination of nuclear magnetic resonance techniques following
enzymatic glycan remodeling to simultaneously generate homogeneous
glycoforms. However, widely applicable methods do not yet exist. To
address this technological gap, immature glycoforms of the immunoglobulin
G1 fragment crystallizable (Fc) were isolated in a homogeneous state
and enzymatically remodeled with [13C,15N]-N-acetylglucosamine (GlcNAc). UDP-[13C,15N]GlcNAc was synthesized enzymatically in a one-pot reaction from
[13C]glucose and [15N-amido]glutamine. Modifying Fc with recombinantly expressed glycosyltransferases
(Gnt1 and Gnt2) and UDP-[13C,15N]GlcNAc resulted
in complete glycoform conversion as judged by mass spectrometry. Two-dimensional
heteronuclear single-quantum coherence spectra of the Gnt1 product,
containing a single [13C,15N]GlcNAc residue
on each N-glycan, showed that the N-glycan is stabilized through interactions with polypeptide residues.
Similar spectra of homogeneous glycoforms, halted at different points
along the N-glycan remodeling pathway, revealed the
presence of an increased level of interaction between the N-glycan and polypeptide at each step, including mannose
trimming, as the N-glycan was converted to a complex-type,
biantennary form. Thus, conformational restriction increases as Fc N-glycan maturation proceeds. Gnt1 and Gnt2 catalyze fundamental
reactions in the synthesis of every glycoprotein with a complex-type N-glycan; thus, the strategies presented herein can be applied
to a broad range of glycoprotein studies.
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Affiliation(s)
- Adam W Barb
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
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449
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Tsai IH, Wang YM, Huang KF. Effects of single N-glycosylation site knockout on folding and defibrinogenating activities of acutobin recombinants from HEK293T. Toxicon 2014; 94:50-9. [PMID: 25533529 DOI: 10.1016/j.toxicon.2014.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/15/2014] [Accepted: 12/18/2014] [Indexed: 11/28/2022]
Abstract
Acutobin, the α-fibrinogenase from Deinagkistrodon acutus venom, contains four N-glycosylation sites with disialylated complex-typed glycans. Here, we explore the functional roles of each of the N-glycan by site-directed mutagenesis. The wild-type (ATB-wt) and single glycan-knockout mutants of recombinant acutobin were prepared from HEK293T, demonstrating that mutations at Asn(77), Asn(81) and Asn(100) impaired the folding while the S79A mutant and various Asn(229)-deglycosylated mutants were correctly folded. Based on homology modeling of acutobin and multiple sequence alignment with various venom thrombin-like enzymes, the importance of a hydrophilic environment at each glycosylation site to the enzyme folding could be rationalized. Remarkably, all the mutants showed similar catalytic activities for the chromogenic substrate and similar thermal stabilities as ATB-wt, suggesting that the glycan knockout did not affect the gross conformation and stability of the active sites. Although SDS-PAGE analyses revealed that ATB-wt and the D229-mutant degraded all human fibrinogen subunits faster but less specifically in vitro as compared with other mutants that cleaved only the α-subunit, ATB-wt and D229-mutant were not able to release fibrinogen-peptide A and thus coagulated human plasma slower than the other mutants did. In the mice model, the defibrinogenating effect of ATB-wt was stronger and lasting-longer than those of all the mutants. Taken together, all the glycans contribute to the pharmacokinetics of acutobin and ATB-wt in vivo, and the microenvironment around the Asn(229)-glycan appears to regulate the fibrinogen-chain specificity of acutobin while the N-glycans at positions 77, 81 and 100 are crucial for its folding.
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Affiliation(s)
- Inn-Ho Tsai
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan.
| | - Ying-Ming Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Kai-Fa Huang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
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450
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Samuelson J, Robbins PW. Effects of N-glycan precursor length diversity on quality control of protein folding and on protein glycosylation. Semin Cell Dev Biol 2014; 41:121-8. [PMID: 25475176 DOI: 10.1016/j.semcdb.2014.11.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 11/24/2014] [Accepted: 11/26/2014] [Indexed: 01/24/2023]
Abstract
Asparagine-linked glycans (N-glycans) of medically important protists have much to tell us about the evolution of N-glycosylation and of N-glycan-dependent quality control (N-glycan QC) of protein folding in the endoplasmic reticulum. While host N-glycans are built upon a dolichol-pyrophosphate-linked precursor with 14 sugars (Glc3Man9GlcNAc2), protist N-glycan precursors vary from Glc3Man9GlcNAc2 (Acanthamoeba) to Man9GlcNAc2 (Trypanosoma) to Glc3Man5GlcNAc2 (Toxoplasma) to Man5GlcNAc2 (Entamoeba, Trichomonas, and Eimeria) to GlcNAc2 (Plasmodium and Giardia) to zero (Theileria). As related organisms have differing N-glycan lengths (e.g. Toxoplasma, Eimeria, Plasmodium, and Theileria), the present N-glycan variation is based upon secondary loss of Alg genes, which encode enzymes that add sugars to the N-glycan precursor. An N-glycan precursor with Man5GlcNAc2 is necessary but not sufficient for N-glycan QC, which is predicted by the presence of the UDP-glucose:glucosyltransferase (UGGT) plus calreticulin and/or calnexin. As many parasites lack glucose in their N-glycan precursor, UGGT product may be identified by inhibition of glucosidase II. The presence of an armless calnexin in Toxoplasma suggests secondary loss of N-glycan QC from coccidia. Positive selection for N-glycan sites occurs in secreted proteins of organisms with N-glycan QC and is based upon an increased likelihood of threonine but not serine in the +2 position versus asparagine. In contrast, there appears to be selection against N-glycan length in Plasmodium and N-glycan site density in Toxoplasma. Finally, there is suggestive evidence for N-glycan-dependent ERAD in Trichomonas, which glycosylates and degrades the exogenous reporter mutant carboxypeptidase Y (CPY*).
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Affiliation(s)
- John Samuelson
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, 72 East Concord St, Evans 425, Boston, MA 02118, USA.
| | - Phillips W Robbins
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, 72 East Concord St, Evans 425, Boston, MA 02118, USA.
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