1
|
Chen S, Pei CX, Xu S, Li H, Liu YS, Wang Y, Jin C, Dean N, Gao XD. Rft1 catalyzes lipid-linked oligosaccharide translocation across the ER membrane. Nat Commun 2024; 15:5157. [PMID: 38886340 PMCID: PMC11182771 DOI: 10.1038/s41467-024-48999-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 05/20/2024] [Indexed: 06/20/2024] Open
Abstract
The eukaryotic asparagine (N)-linked glycan is pre-assembled as a fourteen-sugar oligosaccharide on a lipid carrier in the endoplasmic reticulum (ER). Seven sugars are first added to dolichol pyrophosphate (PP-Dol) on the cytoplasmic face of the ER, generating Man5GlcNAc2-PP-Dol (M5GN2-PP-Dol). M5GN2-PP-Dol is then flipped across the bilayer into the lumen by an ER translocator. Genetic studies identified Rft1 as the M5GN2-PP-Dol flippase in vivo but are at odds with biochemical data suggesting Rft1 is dispensable for flipping in vitro. Thus, the question of whether Rft1 plays a direct or an indirect role during M5GN2-PP-Dol translocation has been controversial for over two decades. We describe a completely reconstituted in vitro assay for M5GN2-PP-Dol translocation and demonstrate that purified Rft1 catalyzes the translocation of M5GN2-PP-Dol across the lipid bilayer. These data, combined with in vitro results demonstrating substrate selectivity and rft1∆ phenotypes, confirm the molecular identity of Rft1 as the M5GN2-PP-Dol ER flippase.
Collapse
Affiliation(s)
- Shuai Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Biopharmaceutical Preparation and Delivery, Chinese Academy of Sciences, Beijing, China
| | - Cai-Xia Pei
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Si Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Hanjie Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yi-Shi Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yicheng Wang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Biopharmaceutical Preparation and Delivery, Chinese Academy of Sciences, Beijing, China
| | - Cheng Jin
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA.
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China.
- Key Laboratory of Biopharmaceutical Preparation and Delivery, Chinese Academy of Sciences, Beijing, China.
| |
Collapse
|
2
|
Shah R, Eklund EA, Radenkovic S, Sadek M, Shammas I, Verberkmoes S, Ng BG, Freeze HH, Edmondson AC, He M, Kozicz T, Altassan R, Morava E. ALG13-Congenital Disorder of Glycosylation (ALG13-CDG): Updated clinical and molecular review and clinical management guidelines. Mol Genet Metab 2024; 142:108472. [PMID: 38703411 DOI: 10.1016/j.ymgme.2024.108472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 05/06/2024]
Abstract
ALG13-Congenital Disorder of Glycosylation (CDG), is a rare X-linked CDG caused by pathogenic variants in ALG13 (OMIM 300776) that affects the N-linked glycosylation pathway. Affected individuals present with a predominantly neurological manifestation during infancy. Epileptic spasms are a common presenting symptom of ALG13-CDG. Other common phenotypes include developmental delay, seizures, intellectual disability, microcephaly, and hypotonia. Current management of ALG13-CDG is targeted to address patients' symptoms. To date, less than 100 individuals have been reported with ALG13-CDG. In this article, an international group of experts in CDG reviewed all reported individuals affected with ALG13-CDG and suggested diagnostic and management guidelines for ALG13-CDG. The guidelines are based on the best available data and expert opinion. Neurological symptoms dominate the phenotype of ALG13-CDG where epileptic spasm is confirmed to be the most common presenting symptom of ALG13-CDG in association with hypotonia and developmental delay. We propose that ACTH/prednisolone treatment should be trialed first, followed by vigabatrin, however ketogenic diet has been shown to have promising results in ALG13-CDG. In order to optimize medical management, we also suggest early cardiac, gastrointestinal, skeletal, and behavioral assessments in affected patients.
Collapse
Affiliation(s)
- Rameen Shah
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Erik A Eklund
- Department of Clinical Sciences, Lund, Pediatrics, Lund University, Lund, Sweden; Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Silvia Radenkovic
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Mustafa Sadek
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Ibrahim Shammas
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Sanne Verberkmoes
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Bobby G Ng
- Human Genetics Program, Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Hudson H Freeze
- Human Genetics Program, Sanford Children's Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Andrew C Edmondson
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, PA, USA
| | - Miao He
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Tamas Kozicz
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA; University of Pécs, Medical School, Pécs, Hungary
| | - Ruqaiah Altassan
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA; Department of Medical Genomics, Centre for Genomics Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
| | - Eva Morava
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA; University of Pécs, Medical School, Pécs, Hungary.
| |
Collapse
|
3
|
Ramírez AS, Locher KP. Structural and mechanistic studies of the N-glycosylation machinery: from lipid-linked oligosaccharide biosynthesis to glycan transfer. Glycobiology 2023; 33:861-872. [PMID: 37399117 PMCID: PMC10859629 DOI: 10.1093/glycob/cwad053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/05/2023] Open
Abstract
N-linked protein glycosylation is a post-translational modification that exists in all domains of life. It involves two consecutive steps: (i) biosynthesis of a lipid-linked oligosaccharide (LLO), and (ii) glycan transfer from the LLO to asparagine residues in secretory proteins, which is catalyzed by the integral membrane enzyme oligosaccharyltransferase (OST). In the last decade, structural and functional studies of the N-glycosylation machinery have increased our mechanistic understanding of the pathway. The structures of bacterial and eukaryotic glycosyltransferases involved in LLO elongation provided an insight into the mechanism of LLO biosynthesis, whereas structures of OST enzymes revealed the molecular basis of sequon recognition and catalysis. In this review, we will discuss approaches used and insight obtained from these studies with a special emphasis on the design and preparation of substrate analogs.
Collapse
Affiliation(s)
- Ana S Ramírez
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich 8093, Switzerland
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich 8093, Switzerland
| |
Collapse
|
4
|
Mei J, Li Z, Zhou S, Chen XL, Wilson RA, Liu W. Effector secretion and stability in the maize anthracnose pathogen Colletotrichum graminicola requires N-linked protein glycosylation and the ER chaperone pathway. THE NEW PHYTOLOGIST 2023; 240:1449-1466. [PMID: 37598305 DOI: 10.1111/nph.19213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 08/01/2023] [Indexed: 08/21/2023]
Abstract
N-linked protein glycosylation is a conserved and essential modification mediating protein processing and quality control in the endoplasmic reticulum (ER), but how this contributes to the infection cycle of phytopathogenic fungi is largely unknown. In this study, we discovered that inhibition of protein N-glycosylation severely affected vegetative growth, hyphal tip development, conidial germination, appressorium formation, and, ultimately, the ability of the maize (Zea mays) anthracnose pathogen Colletotrichum graminicola to infect its host. Quantitative proteomics analysis showed that N-glycosylation can coordinate protein O-glycosylation, glycosylphosphatidylinositol anchor modification, and endoplasmic reticulum quality control (ERQC) by directly targeting the proteins from the corresponding pathway in the ER. We performed a functional study of the N-glycosylation pathway-related protein CgALG3 and of the ERQC pathway-related protein CgCNX1, which demonstrated that N-glycosylation of ER chaperone proteins is essential for effector stability, secretion, and pathogenicity of C. graminicola. Our study provides concrete evidence for the regulation of effector protein stability and secretion by N-glycosylation.
Collapse
Affiliation(s)
- Jie Mei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Zhiqiang Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Shaoqun Zhou
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Xiao-Lin Chen
- State Key Laboratory of Agricultural Microbiology and Provincial Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Richard A Wilson
- Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| |
Collapse
|
5
|
Meyer BH, Adam PS, Wagstaff BA, Kolyfetis GE, Probst AJ, Albers SV, Dorfmueller HC. Agl24 is an ancient archaeal homolog of the eukaryotic N-glycan chitobiose synthesis enzymes. eLife 2022; 11:67448. [PMID: 35394422 PMCID: PMC8993221 DOI: 10.7554/elife.67448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/13/2022] [Indexed: 11/13/2022] Open
Abstract
Protein N-glycosylation is a post-translational modification found in organisms of all domains of life. The crenarchaeal N-glycosylation begins with the synthesis of a lipid-linked chitobiose core structure, identical to that in Eukaryotes, although the enzyme catalyzing this reaction remains unknown. Here, we report the identification of a thermostable archaeal β-1,4-N-acetylglucosaminyltransferase, named archaeal glycosylation enzyme 24 (Agl24), responsible for the synthesis of the N-glycan chitobiose core. Biochemical characterization confirmed its function as an inverting β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol glycosyltransferase. Substitution of a conserved histidine residue, found also in the eukaryotic and bacterial homologs, demonstrated its functional importance for Agl24. Furthermore, bioinformatics and structural modeling revealed similarities of Agl24 to the eukaryotic Alg14/13 and a distant relation to the bacterial MurG, which are catalyzing the same or a similar reaction, respectively. Phylogenetic analysis of Alg14/13 homologs indicates that they are ancient in Eukaryotes, either as a lateral transfer or inherited through eukaryogenesis.
Collapse
Affiliation(s)
- Benjamin H Meyer
- Environmental Microbiology and Biotechnology (EMB), Aquatic Microbial Ecology, University of Duisburg-Essen, Essen, Germany.,Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, United Kingdom.,Molecular Biology of Archaea, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Panagiotis S Adam
- Group for Aquatic Microbial Ecology, Environmental Microbiology and Biotechnology, Faculty of Chemistry University Duisburg-Essen, Essen, Germany
| | - Ben A Wagstaff
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - George E Kolyfetis
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Alexander J Probst
- Centre of Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, Germany
| | - Sonja V Albers
- Molecular Biology of Archaea, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Helge C Dorfmueller
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| |
Collapse
|
6
|
Alg mannosyltransferases: From functional and structural analyses to the lipid-linked oligosaccharide pathway reconstitution. Biochim Biophys Acta Gen Subj 2022; 1866:130112. [PMID: 35217128 DOI: 10.1016/j.bbagen.2022.130112] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 02/06/2022] [Accepted: 02/12/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND N-glycosylation is initiated from the biosynthesis of lipid-linked oligosaccharide (LLO) on the endoplasmic reticulum (ER), which is catalyzed by a series of Alg (asparagine-linked glycosylation) proteins. SCOPE OF REVIEW This review summarizes our recent studies on the enzymology of Alg mannosyltransferases (MTases). We also discuss the membrane topology and physiological importance of several ER cytosolic Alg proteins. MAJOR CONCLUSIONS Utilizing an efficient prokaryotic protein expression system and a new LC-MS quantitative activity assay, we overexpressed all Alg MTases and performed enzymology studies. Moreover, by reconstituting the LLO pathway, the high-yield chemoenzymatic synthesis of high-mannose-type N-glycans was accomplished using recombinant Alg MTases. GENERAL SIGNIFICANCE The analysis of the enzymology and topology of Alg MTases has provided valuable biochemical information in the LLO biosynthesis pathway. In addition, an efficient chemoenzymatic strategy that could prepare various oligomannose-type N-glycans in sufficient amounts was established for further biological assays.
Collapse
|
7
|
Topological and enzymatic analysis of human Alg2 mannosyltransferase reveals its role in lipid-linked oligosaccharide biosynthetic pathway. Commun Biol 2022; 5:117. [PMID: 35136180 PMCID: PMC8827073 DOI: 10.1038/s42003-022-03066-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/20/2022] [Indexed: 11/14/2022] Open
Abstract
N-glycosylation starts with the biosynthesis of lipid-linked oligosaccharide (LLO) on the endoplasmic reticulum (ER). Alg2 mannosyltransferase adds both the α1,3- and α1,6-mannose (Man) onto ManGlcNAc2-pyrophosphate-dolichol (M1Gn2-PDol) in either order to generate the branched M3Gn2-PDol product. The well-studied yeast Alg2 interacts with ER membrane through four hydrophobic domains. Unexpectedly, we show that Alg2 structure has diverged between yeast and humans. Human Alg2 (hAlg2) associates with the ER via a single membrane-binding domain and is markedly more stable in vitro. These properties were exploited to develop a liquid chromatography-mass spectrometry quantitative kinetics assay for studying purified hAlg2. Under physiological conditions, hAlg2 prefers to transfer α1,3-Man onto M1Gn2 before adding the α1,6-Man. However, this bias is altered by an excess of GDP-Man donor or an increased level of M1Gn2 substrate, both of which trigger production of the M2Gn2(α-1,6)-PDol. These results suggest that Alg2 may regulate the LLO biosynthetic pathway by controlling accumulation of M2Gn2 (α-1,6) intermediate. Despite the conservation of N-glycosylation, human and yeast Alg2 structures have diverged with distinct ER-binding topologies. The human enzyme is more stable than the yeast orthologue, and its activity is modulated by the concentration of donor or acceptor substrate.
Collapse
|
8
|
Viinikangas T, Khosrowabadi E, Kellokumpu S. N-Glycan Biosynthesis: Basic Principles and Factors Affecting Its Outcome. EXPERIENTIA SUPPLEMENTUM (2012) 2021; 112:237-257. [PMID: 34687012 DOI: 10.1007/978-3-030-76912-3_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Carbohydrate chains are the most abundant and diverse of nature's biopolymers and represent one of the four fundamental macromolecular building blocks of life together with proteins, nucleic acids, and lipids. Indicative of their essential roles in cells and in multicellular organisms, genes encoding proteins associated with glycosylation account for approximately 2% of the human genome. It has been estimated that 50-80% of all human proteins carry carbohydrate chains-glycans-as part of their structure. Despite cells utilize only nine different monosaccharides for making their glycans, their order and conformational variation in glycan chains together with chain branching differences and frequent post-synthetic modifications can give rise to an enormous repertoire of different glycan structures of which few thousand is estimated to carry important structural or functional information for a cell. Thus, glycans are immensely versatile encoders of multicellular life. Yet, glycans do not represent a random collection of unpredictable structures but rather, a collection of predetermined but still dynamic entities that are present at defined quantities in each glycosylation site of a given protein in a cell, tissue, or organism.In this chapter, we will give an overview of what is currently known about N-glycan synthesis in higher eukaryotes, focusing not only on the processes themselves but also on factors that will affect or can affect the final outcome-the dynamicity and heterogeneity of the N-glycome. We hope that this review will help understand the molecular details underneath this diversity, and in addition, be helpful for those who plan to produce optimally glycosylated antibody-based therapeutics.
Collapse
Affiliation(s)
- Teemu Viinikangas
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Elham Khosrowabadi
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Sakari Kellokumpu
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
| |
Collapse
|
9
|
Zhang J, Wu J, Liu L, Li J. The Crucial Role of Demannosylating Asparagine-Linked Glycans in ERADicating Misfolded Glycoproteins in the Endoplasmic Reticulum. FRONTIERS IN PLANT SCIENCE 2020; 11:625033. [PMID: 33510762 PMCID: PMC7835635 DOI: 10.3389/fpls.2020.625033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 12/08/2020] [Indexed: 05/04/2023]
Abstract
Most membrane and secreted proteins are glycosylated on certain asparagine (N) residues in the endoplasmic reticulum (ER), which is crucial for their correct folding and function. Protein folding is a fundamentally inefficient and error-prone process that can be easily interfered by genetic mutations, stochastic cellular events, and environmental stresses. Because misfolded proteins not only lead to functional deficiency but also produce gain-of-function cellular toxicity, eukaryotic organisms have evolved highly conserved ER-mediated protein quality control (ERQC) mechanisms to monitor protein folding, retain and repair incompletely folded or misfolded proteins, or remove terminally misfolded proteins via a unique ER-associated degradation (ERAD) mechanism. A crucial event that terminates futile refolding attempts of a misfolded glycoprotein and diverts it into the ERAD pathway is executed by removal of certain terminal α1,2-mannose (Man) residues of their N-glycans. Earlier studies were centered around an ER-type α1,2-mannosidase that specifically cleaves the terminal α1,2Man residue from the B-branch of the three-branched N-linked Man9GlcNAc2 (GlcNAc for N-acetylglucosamine) glycan, but recent investigations revealed that the signal that marks a terminally misfolded glycoprotein for ERAD is an N-glycan with an exposed α1,6Man residue generated by members of a unique folding-sensitive α1,2-mannosidase family known as ER-degradation enhancing α-mannosidase-like proteins (EDEMs). This review provides a historical recount of major discoveries that led to our current understanding on the role of demannosylating N-glycans in sentencing irreparable misfolded glycoproteins into ERAD. It also discusses conserved and distinct features of the demannosylation processes of the ERAD systems of yeast, mammals, and plants.
Collapse
Affiliation(s)
- Jianjun Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Jiarui Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Linchuan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Jianming Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Jianming Li, ;
| |
Collapse
|
10
|
SNV discovery and functional candidate gene identification for milk composition based on whole genome resequencing of Holstein bulls with extremely high and low breeding values. PLoS One 2019; 14:e0220629. [PMID: 31369641 PMCID: PMC6675115 DOI: 10.1371/journal.pone.0220629] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 07/19/2019] [Indexed: 02/06/2023] Open
Abstract
We have sequenced the whole genomes of eight proven Holstein bulls from the four half-sib or full-sib families with extremely high and low estimated breeding values (EBV) for milk protein percentage (PP) and fat percentage (FP) using Illumina re-sequencing technology. Consequently, 2.3 billion raw reads were obtained with an average effective depth of 8.1×. After single nucleotide variant (SNV) calling, total 10,961,243 SNVs were identified, and 57,451 of them showed opposite fixed sites between the bulls with high and low EBVs within each family (called as common differential SNVs). Next, we annotated the common differential SNVs based on the bovine reference genome, and observed that 45,188 SNVs (78.70%) were located in the intergenic region of genes and merely 11,871 SNVs (20.67%) located within the protein-coding genes. Of them, 13,099 common differential SNVs that were within or close to protein-coding genes with less than 5 kb were chosen for identification of candidate genes for milk compositions in dairy cattle. By integrated analysis of the 2,657 genes with the GO terms and pathways related to protein and fat metabolism, and the known quantitative trait loci (QTLs) for milk protein and fat traits, we identified 17 promising candidate genes: ALG14, ATP2C1, PLD1, C3H1orf85, SNX7, MTHFD2L, CDKN2D, COL5A3, FDX1L, PIN1, FIG4, EXOC7, LASP1, PGS1, SAO, GPLD1 and MGEA5. Our findings provided an important foundation for further study and a prompt for molecular breeding of dairy cattle.
Collapse
|
11
|
Li ST, Lu TT, Xu XX, Ding Y, Li Z, Kitajima T, Dean N, Wang N, Gao XD. Reconstitution of the lipid-linked oligosaccharide pathway for assembly of high-mannose N-glycans. Nat Commun 2019; 10:1813. [PMID: 31000718 PMCID: PMC6472349 DOI: 10.1038/s41467-019-09752-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 03/29/2019] [Indexed: 11/11/2022] Open
Abstract
The asparagine (N)-linked Man9GlcNAc2 is required for glycoprotein folding and secretion. Understanding how its structure contributes to these functions has been stymied by our inability to produce this glycan as a homogenous structure of sufficient quantities for study. Here, we report the high yield chemoenzymatic synthesis of Man9GlcNAc2 and its biosynthetic intermediates by reconstituting the eukaryotic lipid-linked oligosaccharide (LLO) pathway. Endoplasmic reticulum mannosyltransferases (MTases) are expressed in E. coli and used for mannosylation of the dolichol mimic, phytanyl pyrophosphate GlcNAc2. These recombinant MTases recognize unique substrates and when combined, synthesize end products that precisely mimic those in vivo, demonstrating that ordered assembly of LLO is due to the strict enzyme substrate specificity. Indeed, non-physiological glycans are produced only when the luminal MTases are challenged with cytosolic substrates. Reconstitution of the LLO pathway to synthesize Man9GlcNAc2 in vitro provides an important tool for functional studies of the N-linked glycoprotein biosynthesis pathway. Attachment of the oligosaccharide Man9GlcNAc2 is required for glycoprotein folding and secretion but synthesizing this compound for structural and functional studies has remained challenging. Here, the authors achieve efficient Man9GlcNAc2 synthesis by reconstituting its biosynthetic pathway in vitro.
Collapse
Affiliation(s)
- Sheng-Tao Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Tian-Tian Lu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Xin-Xin Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Yi Ding
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Zijie Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Toshihiko Kitajima
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, 11794-5215, USA
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China.
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China.
| |
Collapse
|
12
|
Xu XX, Li ST, Wang N, Kitajima T, Yoko-O T, Fujita M, Nakanishi H, Gao XD. Structural and functional analysis of Alg1 beta-1,4 mannosyltransferase reveals the physiological importance of its membrane topology. Glycobiology 2019; 28:741-753. [PMID: 29939232 DOI: 10.1093/glycob/cwy060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 06/24/2018] [Indexed: 12/20/2022] Open
Abstract
In eukaryotes, the biosynthesis of a highly conserved dolichol-linked oligosaccharide (DLO) precursor Glc3Man9GlcNAc2-pyrophosphate-dolichol (PP-Dol) begins on the cytoplasmic face of the endoplasmic reticulum (ER) and ends within the lumen. Two functionally distinguished heteromeric glycosyltransferase (GTase) complexes are responsible for the cytosolic DLO assembly. Alg1, a β-1, 4 mannosyltransferase (MTase) physically interacts with Alg2 and Alg11 proteins to form the multienzyme complex which catalyzes the addition of all five mannose to generate the Man5GlcNAc2-PP-Dol intermediate. Despite the fact that Alg1 plays a central role in the formation of the multi-MTase has been confirmed, the topological information of Alg1 including the molecular mechanism of membrane association are still poorly understood. Using a combination of bioinformatics and biological approaches, we have undertaken a structural and functional study on Alg1 protein, in which the enzymatic activities of Alg1 and its variants were monitored by a complementation assay using the GALpr-ALG1 yeast strain, and further confirmed by a liquid chromatography-mass spectrometry-based in vitro quantitative assay. Computational and experimental evidence confirmed Alg1 shares structure similarity with Alg13/14 complex, which has been defined as a membrane-associated GT-B GTase. Particularly, we provide clear evidence that the N-terminal transmembrane domain including the following positively charged amino acids and an N-terminal amphiphilic-like α helix domain exposed on the protein surface strictly coordinate the Alg1 orientation on the ER membrane. This work provides detailed membrane topology of Alg1 and further reveals its biological importance at the spatial aspect in coordination of cytosolic DLO biosynthesis.
Collapse
Affiliation(s)
- Xin-Xin Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Sheng-Tao Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Toshihiko Kitajima
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Takehiko Yoko-O
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 6, Higashi, Tsukuba, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| |
Collapse
|
13
|
Kvarnung M, Taylan F, Nilsson D, Anderlid BM, Malmgren H, Lagerstedt-Robinson K, Holmberg E, Burstedt M, Nordenskjöld M, Nordgren A, Lundberg ES. Genomic screening in rare disorders: New mutations and phenotypes, highlighting ALG14 as a novel cause of severe intellectual disability. Clin Genet 2018; 94:528-537. [PMID: 30221345 DOI: 10.1111/cge.13448] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 09/04/2018] [Accepted: 09/11/2018] [Indexed: 01/20/2023]
Abstract
We have investigated 20 consanguineous families with multiple children affected by rare disorders. Detailed clinical examinations, exome sequencing of affected as well as unaffected family members and further validation of likely pathogenic variants were performed. In 16/20 families, we identified pathogenic variants in autosomal recessive disease genes (ALMS1, PIGT, FLVCR2, TFG, CYP7B1, ALG14, EXOSC3, MEGF10, ASAH1, WDR62, ASPM, PNPO, ERCC5, KIAA1109, RIPK4, MAN1B1). A number of these genes have only rarely been reported previously and our findings thus confirm them as disease genes, further delineate the associated phenotypes and expand the mutation spectrum with reports of novel variants. We highlight the findings in two affected siblings with splice altering variants in ALG14 and propose a new clinical entity, which includes severe intellectual disability, epilepsy, behavioral problems and mild dysmorphic features, caused by biallelic variants in ALG14.
Collapse
Affiliation(s)
- Malin Kvarnung
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Fulya Taylan
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Daniel Nilsson
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Science for Life Laboratory, Karolinska Institutet Science Park, Stockholm, Sweden
| | - Britt-Marie Anderlid
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Helena Malmgren
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Kristina Lagerstedt-Robinson
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Eva Holmberg
- Department of Medical Bioscience, Medical and Clinical Genetics, Umeå University, Umeå, Sweden
| | - Magnus Burstedt
- Department of Medical Bioscience, Medical and Clinical Genetics, Umeå University, Umeå, Sweden
| | - Magnus Nordenskjöld
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Ann Nordgren
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Elisabeth S Lundberg
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| |
Collapse
|
14
|
Rodríguez Cruz PM, Palace J, Beeson D. The Neuromuscular Junction and Wide Heterogeneity of Congenital Myasthenic Syndromes. Int J Mol Sci 2018; 19:ijms19061677. [PMID: 29874875 PMCID: PMC6032286 DOI: 10.3390/ijms19061677] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/17/2018] [Accepted: 05/21/2018] [Indexed: 01/16/2023] Open
Abstract
Congenital myasthenic syndromes (CMS) are genetic disorders characterised by impaired neuromuscular transmission. This review provides an overview on CMS and highlights recent advances in the field, including novel CMS causative genes and improved therapeutic strategies. CMS due to mutations in SLC5A7 and SLC18A3, impairing the synthesis and recycling of acetylcholine, have recently been described. In addition, a novel group of CMS due to mutations in SNAP25B, SYT2, VAMP1, and UNC13A1 encoding molecules implicated in synaptic vesicles exocytosis has been characterised. The increasing number of presynaptic CMS exhibiting CNS manifestations along with neuromuscular weakness demonstrate that the myasthenia can be only a small part of a much more extensive disease phenotype. Moreover, the spectrum of glycosylation abnormalities has been increased with the report that GMPPB mutations can cause CMS, thus bridging myasthenic disorders with dystroglycanopathies. Finally, the discovery of COL13A1 mutations and laminin α5 deficiency has helped to draw attention to the role of extracellular matrix proteins for the formation and maintenance of muscle endplates. The benefit of β2-adrenergic agonists alone or combined with pyridostigmine or 3,4-Dyaminopiridine is increasingly being reported for different subtypes of CMS including AChR-deficiency and glycosylation abnormalities, thus expanding the therapeutic repertoire available.
Collapse
Affiliation(s)
- Pedro M Rodríguez Cruz
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford OX3 9DS, UK.
| | - Jacqueline Palace
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford OX3 9DS, UK.
| |
Collapse
|
15
|
Bemena LD, Mukama O, Wang N, Gao XD, Nakanishi H. Characterization of a yeast sporulation-specific P450 family protein, Dit2, using an in vitro assay to crosslink formyl tyrosine. J Biochem 2018; 163:123-131. [PMID: 29365103 DOI: 10.1093/jb/mvx067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/28/2017] [Indexed: 11/14/2022] Open
Abstract
The outermost layer of the yeast Saccharomyces cerevisiae spore, termed the dityrosine layer, is primarily composed of bisformyl dityrosine. Bisformyl dityrosine is produced in the spore cytosol by crosslinking of two formyl tyrosine molecules, after which it is transported to the nascent spore wall and assembled into the dityrosine layer by an unknown mechanism. A P450 family protein, Dit2, is believed to mediate the crosslinking of bisformyl dityrosine molecules. To characterize Dit2 and gain insight into the biological process of dityrosine layer formation, we performed an in vitro assay to crosslink formyl tyrosine with using permeabilized cells. For an unknown reason, the production of bisformyl dityrosine could not be confirmed under our experimental conditions, but dityrosine was detected in acid hydrolysates of the reaction mixtures in a Dit2 dependent manner. Thus, Dit2 mediated the crosslinking of formyl tyrosine in vitro. Dityrosine was detected when formyl tyrosine, but not tyrosine, was used as a substrate and the reaction required NADPH as a cofactor. Intriguingly, apart from Dit2, we found that the spore wall, but not the vegetative cell wall, contains bisformyl dityrosine crosslinking activity. This activity may be involved in the assembly of the dityrosine layer.
Collapse
Affiliation(s)
- Leo D Bemena
- Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Omar Mukama
- Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Ning Wang
- Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Xiao-Dong Gao
- Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Hideki Nakanishi
- Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| |
Collapse
|
16
|
Li ST, Wang N, Xu XX, Fujita M, Nakanishi H, Kitajima T, Dean N, Gao XD. Alternative routes for synthesis of N-linked glycans by Alg2 mannosyltransferase. FASEB J 2018; 32:2492-2506. [PMID: 29273674 DOI: 10.1096/fj.201701267r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Asparagine ( N)-linked glycosylation requires the ordered, stepwise synthesis of lipid-linked oligosaccharide (LLO) precursor Glc3Man9GlcNAc2-pyrophosphate-dolichol (Glc3Man9Gn2-PDol) on the endoplasmic reticulum. The fourth and fifth steps of LLO synthesis are catalyzed by Alg2, an unusual mannosyltransferase (MTase) with two different MTase activities; Alg2 adds both an α1,3- and α1,6-mannose onto ManGlcNAc2-PDol to form the trimannosyl core Man3GlcNAc2-PDol. The biochemical properties of Alg2 are controversial and remain undefined. In this study, a liquid chromatography/mass spectrometry-based quantitative assay was established and used to analyze the MTase activities of purified yeast Alg2. Alg2-dependent Man3GlcNAc2-PDol production relied on net-neutral lipids with a propensity to form bilayers. We further showed addition of the α1,3- and α1,6-mannose can occur independently in either order but at differing rates. The conserved C-terminal EX7E motif, N-terminal cytosolic tail, and 3 G-rich loop motifs in Alg2 play crucial roles for these activities, both in vitro and in vivo. These findings provide insight into the unique bifunctionality of Alg2 during LLO synthesis and lead to a new model in which alternative, independent routes exist for Alg2 catalysis of the trimannosyl core oligosaccharide.-Li, S.-T., Wang, N., Xu, X.-X., Fujita, M., Nakanishi, H., Kitajima, T., Dean, N., Gao, X.-D. Alternative routes for synthesis of N-linked glycans by Alg2 mannosyltransferase.
Collapse
Affiliation(s)
- Sheng-Tao Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xin-Xin Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Toshihiko Kitajima
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| |
Collapse
|
17
|
Mathieu-Rivet E, Lerouge P, Bardor M. Chlamydomonas reinhardtii: Protein Glycosylation and Production of Biopharmaceuticals. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-3-319-66360-9_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
18
|
Xu XX, Komatsuzaki A, Chiba Y, Gao XD, Yoko-O T. PER1, GUP1 and CWH43 of methylotrophic yeast Ogataea minuta are involved in cell wall integrity. Yeast 2017; 35:225-236. [PMID: 29027702 DOI: 10.1002/yea.3285] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 09/25/2017] [Accepted: 10/03/2017] [Indexed: 12/23/2022] Open
Abstract
In eukaryotes, the glycosylphosphatidylinositol (GPI) modification of many glycoproteins on the cell surface is highly conserved. The lipid moieties of GPI-anchored proteins undergo remodelling processes during their maturation. To date, the products of the PER1, GUP1 and CWH43 genes of the yeast Saccharomyces cerevisiae have been shown to be involved in the lipid remodelling. Here, we focus on the putative GPI remodelling pathway in the methylotrophic yeast Ogataea minuta. We found that the O. minuta homologues of PER1, GUP1 and CWH43 are functionally compatible with those of S. cerevisiae. Disruption of GUP1 or CWH43 in O. minuta caused a growth defect under non-permissive conditions. The O. minuta per1Δ mutant exhibited a more fragile phenotype than the gup1Δ or cwh43Δ mutants. To address the role of GPI modification in O. minuta, we assessed the effect of these mutations on the processing and localization of the O. minuta homologues of the Gas1 protein; in S. cerevisiae, Gas1p is an abundant and well-characterized GPI-anchored protein. We found that O. minuta possesses two copies of the GAS1 gene, which we designate GAS1A and GAS1B. Microscopy and western blotting analysis showed mislocalization and/or lower retention of Gas1Ap and Gas1Bp within the membrane fraction in per1Δ or gup1Δ mutant cells, suggesting the significance of lipid remodelling for GPI-anchored proteins in O. minuta. Localization behaviour of Gas1Bp differed from that of Gas1Ap. Our data reveals, for the first time (to our knowledge), the existence of genes related to GPI anchor remodelling in O. minuta cells.
Collapse
Affiliation(s)
- Xin-Xin Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China.,Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan
| | - Akiko Komatsuzaki
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan
| | - Yasunori Chiba
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Takehiko Yoko-O
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, 305-8568, Japan
| |
Collapse
|
19
|
Poljak K, Selevsek N, Ngwa E, Grossmann J, Losfeld ME, Aebi M. Quantitative Profiling of N-linked Glycosylation Machinery in Yeast Saccharomyces cerevisiae. Mol Cell Proteomics 2017; 17:18-30. [PMID: 28993419 DOI: 10.1074/mcp.ra117.000096] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Indexed: 11/06/2022] Open
Abstract
Asparagine-linked glycosylation is a common posttranslational protein modification regulating the structure, stability and function of many proteins. The N-linked glycosylation machinery involves enzymes responsible for the assembly of the lipid-linked oligosaccharide (LLO), which is then transferred to the asparagine residues on the polypeptides by the enzyme oligosaccharyltransferase (OST). A major goal in the study of protein glycosylation is to establish quantitative methods for the analysis of site-specific extent of glycosylation. We developed a sensitive approach to examine glycosylation site occupancy in Saccharomyces cerevisiae by coupling stable isotope labeling (SILAC) approach to parallel reaction monitoring (PRM) mass spectrometry (MS). We combined the method with genetic tools and validated the approach with the identification of novel glycosylation sites dependent on the Ost3p and Ost6p regulatory subunits of OST. Based on the observations that alternations in LLO substrate structure and OST subunits activity differentially alter the systemic output of OST, we conclude that sequon recognition is a direct property of the catalytic subunit Stt3p, auxiliary subunits such as Ost3p and Ost6p extend the OST substrate range by modulating interfering pathways such as protein folding. In addition, our proteomics approach revealed a novel regulatory network that connects isoprenoid lipid biosynthesis and LLO substrate assembly.
Collapse
Affiliation(s)
- Kristina Poljak
- From the ‡Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Nathalie Selevsek
- §Functional Genomics Center Zurich, UZH/ETH Zurich, CH-8057 Zurich, Switzerland
| | - Elsy Ngwa
- From the ‡Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Jonas Grossmann
- §Functional Genomics Center Zurich, UZH/ETH Zurich, CH-8057 Zurich, Switzerland
| | - Marie Estelle Losfeld
- From the ‡Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Markus Aebi
- From the ‡Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland;
| |
Collapse
|
20
|
Ramírez AS, Boilevin J, Lin CW, Ha Gan B, Janser D, Aebi M, Darbre T, Reymond JL, Locher KP. Chemo-enzymatic synthesis of lipid-linked GlcNAc2Man5 oligosaccharides using recombinant Alg1, Alg2 and Alg11 proteins. Glycobiology 2017; 27:726-733. [PMID: 28575298 PMCID: PMC5881667 DOI: 10.1093/glycob/cwx045] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/10/2017] [Accepted: 05/27/2017] [Indexed: 11/14/2022] Open
Abstract
The biosynthesis of eukaryotic lipid-linked oligosaccharides (LLOs) that act as donor substrates in eukaryotic protein N-glycosylation starts on the cytoplasmic side of the endoplasmic reticulum and includes the sequential addition of five mannose units to dolichol-pyrophosphate-GlcNAc2. These reactions are catalyzed by the Alg1, Alg2 and Alg11 gene products and yield Dol-PP-GlcNAc2Man5, an LLO intermediate that is subsequently flipped to the lumen of the endoplasmic reticulum. While the purification of active Alg1 has previously been described, Alg11 and Alg2 have been mostly studied in vivo. We here describe the expression and purification of functional, full length Alg2 protein. Along with the purified soluble domains Alg1 and Alg11, we used Alg2 to chemo-enzymatically generate Dol-PP-GlcNAc2Man5 analogs starting from synthetic LLOs containing a chitobiose moiety coupled to oligoprenyl carriers of distinct lengths (C10, C15, C20 and C25). We found that while the addition of the first mannose unit by Alg1 was successful with all of the LLO molecules, the Alg2-catalyzed reaction was only efficient if the acceptor LLOs contained a sufficiently long lipid tail of four or five isoprenyl units (C20 and C25). Following conversion with Alg11, the resulting C20 or C25 -containing GlcNAc2Man5 LLO analogs were successfully used as donor substrates of purified single-subunit oligosaccharyltransferase STT3A from Trypanosoma brucei. Our results provide a chemo-enzymatic method for the generation of eukaryotic LLO analogs and are the basis of subsequent mechanistic studies of the enigmatic Alg2 reaction mechanism.
Collapse
Affiliation(s)
- Ana S Ramírez
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Schafmattstrasse 20, CH-8093 Zürich, Switzerland
| | - Jérémy Boilevin
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Chia-Wei Lin
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Bee Ha Gan
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Daniel Janser
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Schafmattstrasse 20, CH-8093 Zürich, Switzerland
| | - Markus Aebi
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Tamis Darbre
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Jean-Louis Reymond
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Kaspar P Locher
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Schafmattstrasse 20, CH-8093 Zürich, Switzerland
| |
Collapse
|
21
|
Niewiadomska M, Janik A, Perlińska-Lenart U, Piłsyk S, Palamarczyk G, Kruszewska JS. The role of Alg13 N-acetylglucosaminyl transferase in the expression of pathogenic features of Candida albicans. Biochim Biophys Acta Gen Subj 2017; 1861:789-801. [DOI: 10.1016/j.bbagen.2017.01.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 01/16/2017] [Accepted: 01/21/2017] [Indexed: 01/09/2023]
|
22
|
AglH, a thermophilic UDP-N-acetylglucosamine-1-phosphate:dolichyl phosphate GlcNAc-1-phosphotransferase initiating protein N-glycosylation pathway in Sulfolobus acidocaldarius, is capable of complementing the eukaryal Alg7. Extremophiles 2016; 21:121-134. [PMID: 27822701 PMCID: PMC5222938 DOI: 10.1007/s00792-016-0890-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 10/24/2016] [Indexed: 10/31/2022]
Abstract
AglH, a predicted UDP-GlcNAc-1-phosphate:dolichyl phosphate GlcNAc-1-phosphotransferase, is initiating the protein N-glycosylation pathway in the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius. AglH successfully replaced the endogenous GlcNAc-1-phosphotransferase activity of Alg7 in a conditional lethal Saccharomyces cerevisiae strain, in which the first step of the eukaryal protein N-glycosylation process was repressed. This study is one of the few examples of cross-domain complementation demonstrating a conserved polyprenyl phosphate transferase reaction within the eukaryal and archaeal domain like it was demonstrated for Methanococcus voltae (Shams-Eldin et al. 2008). The topology prediction and the alignment of the AglH membrane protein with GlcNAc-1-phosphotransferases from the three domains of life show significant conservation of amino acids within the different proposed cytoplasmic loops. Alanine mutations of selected conserved amino acids in the putative cytoplasmic loops II (D100), IV (F220) and V (F264) demonstrated the importance of these amino acids for cross-domain AlgH activity in in vitro complementation assays in S. cerevisiae. Furthermore, antibiotic treatment interfering directly with the activity of dolichyl phosphate GlcNAc-1-phosphotransferases confirmed the essentiality of N-glycosylation for cell survival.
Collapse
|
23
|
Lombard J. The multiple evolutionary origins of the eukaryotic N-glycosylation pathway. Biol Direct 2016; 11:36. [PMID: 27492357 PMCID: PMC4973528 DOI: 10.1186/s13062-016-0137-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/26/2016] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND The N-glycosylation is an essential protein modification taking place in the membranes of the endoplasmic reticulum (ER) in eukaryotes and the plasma membranes in archaea. It shares mechanistic similarities based on the use of polyisoprenol lipid carriers with other glycosylation pathways involved in the synthesis of bacterial cell wall components (e.g. peptidoglycan and teichoic acids). Here, a phylogenomic analysis was carried out to examine the validity of rival hypotheses suggesting alternative archaeal or bacterial origins to the eukaryotic N-glycosylation pathway. RESULTS The comparison of several polyisoprenol-based glycosylation pathways from the three domains of life shows that most of the implicated proteins belong to a limited number of superfamilies. The N-glycosylation pathway enzymes are ancestral to the eukaryotes, but their origins are mixed: Alg7, Dpm and maybe also one gene of the glycosyltransferase 1 (GT1) superfamily and Stt3 have proteoarchaeal (TACK superphylum) origins; alg2/alg11 may have resulted from the duplication of the original GT1 gene; the lumen glycosyltransferases were probably co-opted and multiplied through several gene duplications during eukaryogenesis; Alg13/Alg14 are more similar to their bacterial homologues; and Alg1, Alg5 and a putative flippase have unknown origins. CONCLUSIONS The origin of the eukaryotic N-glycosylation pathway is not unique and less straightforward than previously thought: some basic components likely have proteoarchaeal origins, but the pathway was extensively developed before the eukaryotic diversification through multiple gene duplications, protein co-options, neofunctionalizations and even possible horizontal gene transfers from bacteria. These results may have important implications for our understanding of the ER evolution and eukaryogenesis. REVIEWERS This article was reviewed by Pr. Patrick Forterre and Dr. Sergei Mekhedov (nominated by Editorial Board member Michael Galperin).
Collapse
Affiliation(s)
- Jonathan Lombard
- National Evolutionary Synthesis Center, 2024 W. Main Street Suite A200, Durham, NC, 27705, USA.
- Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
| |
Collapse
|
24
|
Kellokumpu S, Hassinen A, Glumoff T. Glycosyltransferase complexes in eukaryotes: long-known, prevalent but still unrecognized. Cell Mol Life Sci 2016; 73:305-25. [PMID: 26474840 PMCID: PMC7079781 DOI: 10.1007/s00018-015-2066-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/28/2015] [Accepted: 10/08/2015] [Indexed: 01/08/2023]
Abstract
Glycosylation is the most common and complex cellular modification of proteins and lipids. It is critical for multicellular life and its abrogation often leads to a devastating disease. Yet, the underlying mechanistic details of glycosylation in both health and disease remain unclear. Partly, this is due to the complexity and dynamicity of glycan modifications, and the fact that not all the players are taken into account. Since late 1960s, a vast number of studies have demonstrated that glycosyltransferases typically form homomeric and heteromeric complexes with each other in yeast, plant and animal cells. To propagate their acceptance, we will summarize here accumulated data for their prevalence and potential functional importance for glycosylation focusing mainly on their mutual interactions, the protein domains mediating these interactions, and enzymatic activity changes that occur upon complex formation. Finally, we will highlight the few existing 3D structures of these enzyme complexes to pinpoint their individual nature and to emphasize that their lack is the main obstacle for more detailed understanding of how these enzyme complexes interact and function in a eukaryotic cell.
Collapse
Affiliation(s)
- Sakari Kellokumpu
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland.
| | - Antti Hassinen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland
| | - Tuomo Glumoff
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland
| |
Collapse
|
25
|
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
| |
Collapse
|
26
|
Affiliation(s)
- Yoichiro Harada
- Department of Systems Biology in Thromboregulation, Kagoshima University
| |
Collapse
|
27
|
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.
Collapse
|
28
|
Cova M, Rodrigues JA, Smith TK, Izquierdo L. Sugar activation and glycosylation in Plasmodium. Malar J 2015; 14:427. [PMID: 26520586 PMCID: PMC4628283 DOI: 10.1186/s12936-015-0949-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/21/2015] [Indexed: 11/24/2022] Open
Abstract
Glycoconjugates are important mediators of host-pathogen interactions and are usually very abundant in the surface of many protozoan parasites. However, in the particular case of Plasmodium species, previous works show that glycosylphosphatidylinositol anchor modifications, and to an unknown extent, a severely truncated N-glycosylation are the only glycosylation processes taking place in the parasite. Nevertheless, a detailed analysis of the parasite genome and the recent identification of the sugar nucleotide precursors biosynthesized by Plasmodium falciparum support a picture in which several overlooked, albeit not very prominent glycosylations may be occurring during the parasite life cycle. In this work,
the authors review recent developments in the characterization of the biosynthesis of glycosylation precursors in the parasite, focusing on the outline of the possible fates of these precursors.
Collapse
Affiliation(s)
- Marta Cova
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.
| | - João A Rodrigues
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, Edificio Egas Moniz, 1649-028, Lisbon, Portugal.
| | - Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK.
| | - Luis Izquierdo
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.
| |
Collapse
|
29
|
Abstract
This review presents principles of glycosylation, describes the relevant glycosylation pathways and their related disorders, and highlights some of the neurological aspects and issues that continue to challenge researchers. More than 100 rare human genetic disorders that result from deficiencies in the different glycosylation pathways are known today. Most of these disorders impact the central and/or peripheral nervous systems. Patients typically have developmental delays/intellectual disabilities, hypotonia, seizures, neuropathy, and metabolic abnormalities in multiple organ systems. Among these disorders there is great clinical diversity because all cell types differentially glycosylate proteins and lipids. The patients have hundreds of misglycosylated products, which afflict a myriad of processes, including cell signaling, cell-cell interaction, and cell migration. This vast complexity in glycan composition and function, along with the limited availability of analytic tools, has impeded the identification of key glycosylated molecules that cause pathologies. To date, few critical target proteins have been pinpointed.
Collapse
|
30
|
Srichaisupakit A, Ohashi T, Misaki R, Fujiyama K. Production of initial-stage eukaryotic N-glycan and its protein glycosylation in Escherichia coli. J Biosci Bioeng 2014; 119:399-405. [PMID: 25449758 DOI: 10.1016/j.jbiosc.2014.09.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 09/13/2014] [Accepted: 09/17/2014] [Indexed: 11/20/2022]
Abstract
N-Glycosylation is a ubiquitous protein post-translational modification mechanism in eukaryotes. In this work, a synthetic pathway containing glycosyltransferases from Saccharomyces cerevisiae was introduced to Escherichia coli to synthesize lipid-linked mannosyl-chitobiose (Man-GlcNAc2) and trimannosyl-chitobiose (Man3-GlcNAc2). Transfer of Man3-GlcNAc2 onto a model periplasmic protein occurred in the engineered E. coli cell using oligosaccharyltransferase PglB from Campylobacter jejuni. Mass spectrometric analysis of the fluorescently labeled N-glycan indicated a glycan signal composed of 2 HexNAc and 3 Hex residues. The reversed-phase HPLC analysis suggested that the Hex residues were α1,3-, α1,6- and β1,4-linked mannoses. These results indicated that the constructed system synthesizes a Man3-GlcNAc2, identical to that observed in an early eukaryotic dolichol pathway. Finally, glycopeptide mass spectrometry confirmed the transfer of the assembled glycan moiety onto an engineered glycosylation motif of recombinant maltose binding protein. Surprisingly, the Man3-GlcNAc2 structure but not Man-GlcNAc2 was transferred onto maltose binding protein. This work showed that PglB protein might be able to accommodate the transfer of the further engineered glycan with greater complexity.
Collapse
Affiliation(s)
| | - Takao Ohashi
- International Center for Biotechnology, Osaka University, Suita, Osaka 565-0871, Japan
| | - Ryo Misaki
- International Center for Biotechnology, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kazuhito Fujiyama
- International Center for Biotechnology, Osaka University, Suita, Osaka 565-0871, Japan.
| |
Collapse
|
31
|
Inherited disorders of the neuromuscular junction: an update. J Neurol 2014; 261:2234-43. [PMID: 25305004 DOI: 10.1007/s00415-014-7520-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 09/23/2014] [Indexed: 10/24/2022]
Abstract
Congenital myasthenic syndromes (CMSs) are a group of heterogeneous inherited disorders caused by mutations in genes affecting the function and structure of the neuromuscular junction. This review updates the reader on established and novel subtypes of congenital myasthenia, and the treatment strategies for these increasingly heterogeneous disorders. The discovery of mutations associated with the N-glycosylation pathway and in the family of serine peptidases has shown that causative genes encoding ubiquitously expressed molecules can produce defects at the human neuromuscular junction. By contrast, mutations in lipoprotein-like receptor 4 (LRP4), a long-time candidate gene for congenital myasthenia, and a novel phenotype of myasthenia with distal weakness and atrophy due to mutations in AGRN have now been described. In addition, a pathogenic splicing mutation in a nonfunctional exon of CHRNA1 has been reported emphasizing the importance of analysing nonfunctional exons in genetic analysis. The benefit of salbutamol and ephedrine alone or combined with pyridostigmine or 3,4-DAP is increasingly being reported for particular subtypes of CMS.
Collapse
|
32
|
|
33
|
Monies DM, Al-Hindi HN, Al-Muhaizea MA, Jaroudi DJ, Al-Younes B, Naim EA, Wakil SM, Meyer BF, Bohlega S. Clinical and pathological heterogeneity of a congenital disorder of glycosylation manifesting as a myasthenic/myopathic syndrome. Neuromuscul Disord 2014; 24:353-9. [DOI: 10.1016/j.nmd.2013.12.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 12/07/2013] [Accepted: 12/24/2013] [Indexed: 01/05/2023]
|
34
|
Freeze HH, Chong JX, Bamshad MJ, Ng BG. Solving glycosylation disorders: fundamental approaches reveal complicated pathways. Am J Hum Genet 2014; 94:161-75. [PMID: 24507773 DOI: 10.1016/j.ajhg.2013.10.024] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Indexed: 11/30/2022] Open
Abstract
Over 100 human genetic disorders result from mutations in glycosylation-related genes. In 2013, a new glycosylation disorder was reported every 17 days. This trend will probably continue given that at least 2% of the human genome encodes glycan-biosynthesis and -recognition proteins. Established biosynthetic pathways provide many candidate genes, but finding unanticipated mutated genes will offer new insights into glycosylation. Simple glycobiomarkers can be used in narrowing the candidates identified by exome and genome sequencing, and those can be validated by glycosylation analysis of serum or cells from affected individuals. Model organisms will expand the understanding of these mutations' impact on glycosylation and pathology. Here, we highlight some recently discovered glycosylation disorders and the barriers, breakthroughs, and surprises they presented. We predict that some glycosylation disorders might occur with greater frequency than current estimates of their prevalence. Moreover, the prevalence of some disorders differs substantially between European and African Americans.
Collapse
Affiliation(s)
- Hudson H Freeze
- Human Genetics Program, Sanford Children's Health Research Center, Sanford Burnham Medical Research Institute, La Jolla, CA 92037, USA.
| | - Jessica X Chong
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Michael J Bamshad
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Bobby G Ng
- Human Genetics Program, Sanford Children's Health Research Center, Sanford Burnham Medical Research Institute, La Jolla, CA 92037, USA
| |
Collapse
|
35
|
Albesa-Jové D, Giganti D, Jackson M, Alzari PM, Guerin ME. Structure-function relationships of membrane-associated GT-B glycosyltransferases. Glycobiology 2013; 24:108-24. [PMID: 24253765 DOI: 10.1093/glycob/cwt101] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Membrane-associated GT-B glycosyltransferases (GTs) comprise a large family of enzymes that catalyze the transfer of a sugar moiety from nucleotide-sugar donors to a wide range of membrane-associated acceptor substrates, mostly in the form of lipids and proteins. As a consequence, they generate a significant and diverse amount of glycoconjugates in biological membranes, which are particularly important in cell-cell, cell-matrix and host-pathogen recognition events. Membrane-associated GT-B enzymes display two "Rossmann-fold" domains separated by a deep cleft that includes the catalytic center. They associate permanently or temporarily to the phospholipid bilayer by a combination of hydrophobic and electrostatic interactions. They have the remarkable property to access both hydrophobic and hydrophilic substrates that reside within chemically distinct environments catalyzing their enzymatic transformations in an efficient manner. Here, we discuss the considerable progress that has been made in recent years in understanding the molecular mechanism that governs substrate and membrane recognition, and the impact of the conformational transitions undergone by these GTs during the catalytic cycle.
Collapse
Affiliation(s)
- David Albesa-Jové
- Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Científicas - Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain
| | | | | | | | | |
Collapse
|
36
|
Abstract
Every living cell is covered with a dense and complex array of covalently attached sugars or sugar chains. The majority of these glycans are linked to proteins via the so-called glycosylation process. Protein glycosylation is found in all three domains of life: Eukarya, Bacteria and Archaea. However, on the basis of the limit in analytic tools for glycobiology and genetics in Archaea, only in the last few years has research on archaeal glycosylation pathways started mainly in the Euryarchaeota Haloferax volcanii, Methanocaldococcus maripaludis and Methanococcus voltae. Recently, major steps of the crenarchaeal glycosylation process of the thermoacidophilic archaeon Sulfolobus acidocaldarius have been described. The present review summarizes the proposed N-glycosylation pathway of S. acidocaldarius, describing the phenotypes of the mutants disrupted in N-glycan biosynthesis as well as giving insights into the archaeal O-linked and glycosylphosphatidylinositol anchor glycosylation process.
Collapse
|
37
|
Breitling J, Aebi M. N-linked protein glycosylation in the endoplasmic reticulum. Cold Spring Harb Perspect Biol 2013; 5:a013359. [PMID: 23751184 DOI: 10.1101/cshperspect.a013359] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The attachment of glycans to asparagine residues of proteins is an abundant and highly conserved essential modification in eukaryotes. The N-glycosylation process includes two principal phases: the assembly of a lipid-linked oligosaccharide (LLO) and the transfer of the oligosaccharide to selected asparagine residues of polypeptide chains. Biosynthesis of the LLO takes place at both sides of the endoplasmic reticulum (ER) membrane and it involves a series of specific glycosyltransferases that catalyze the assembly of the branched oligosaccharide in a highly defined way. Oligosaccharyltransferase (OST) selects the Asn-X-Ser/Thr consensus sequence on polypeptide chains and generates the N-glycosidic linkage between the side-chain amide of asparagine and the oligosaccharide. This ER-localized pathway results in a systemic modification of the proteome, the basis for the Golgi-catalyzed modification of the N-linked glycans, generating the large diversity of N-glycoproteome in eukaryotic cells. This article focuses on the processes in the ER. Based on the highly conserved nature of this pathway we concentrate on the mechanisms in the eukaryotic model organism Saccharomyces cerevisiae.
Collapse
Affiliation(s)
- Jörg Breitling
- Institute of Microbiology, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
| | | |
Collapse
|
38
|
Aebi M. N-linked protein glycosylation in the ER. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2430-7. [PMID: 23583305 DOI: 10.1016/j.bbamcr.2013.04.001] [Citation(s) in RCA: 484] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 03/25/2013] [Accepted: 04/01/2013] [Indexed: 01/18/2023]
Abstract
N-linked protein glycosylation in the endoplasmic reticulum (ER) is a conserved two phase process in eukaryotic cells. It involves the assembly of an oligosaccharide on a lipid carrier, dolichylpyrophosphate and the transfer of the oligosaccharide to selected asparagine residues of polypeptides that have entered the lumen of the ER. The assembly of the oligosaccharide (LLO) takes place at the ER membrane and requires the activity of several specific glycosyltransferases. The biosynthesis of the LLO initiates at the cytoplasmic side of the ER membrane and terminates in the lumen where oligosaccharyltransferase (OST) selects N-X-S/T sequons of polypeptide and generates the N-glycosidic linkage between the side chain amide of asparagine and the oligosaccharide. The N-glycosylation pathway in the ER modifies a multitude of proteins at one or more asparagine residues with a unique carbohydrate structure that is used as a signalling molecule in their folding pathway. In a later stage of glycoprotein processing, the same systemic modification is used in the Golgi compartment, but in this process, remodelling of the N-linked glycans in a protein-, cell-type and species specific manner generates the high structural diversity of N-linked glycans observed in eukaryotic organisms. This article summarizes the current knowledge of the N-glycosylation pathway in the ER that results in the covalent attachment of an oligosaccharide to asparagine residues of polypeptide chains and focuses on the model organism Saccharomyces cerevisiae. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
Collapse
Affiliation(s)
- Markus Aebi
- Department of Biology, Institute of Microbiology, Zurich, Switzerland.
| |
Collapse
|
39
|
Cossins J, Belaya K, Hicks D, Salih MA, Finlayson S, Carboni N, Liu WW, Maxwell S, Zoltowska K, Farsani GT, Laval S, Seidhamed MZ, Donnelly P, Bentley D, McGowan SJ, Müller J, Palace J, Lochmüller H, Beeson D. Congenital myasthenic syndromes due to mutations in ALG2 and ALG14. Brain 2013; 136:944-56. [PMID: 23404334 PMCID: PMC3580273 DOI: 10.1093/brain/awt010] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 12/13/2012] [Accepted: 12/19/2012] [Indexed: 01/22/2023] Open
Abstract
Congenital myasthenic syndromes are a heterogeneous group of inherited disorders that arise from impaired signal transmission at the neuromuscular synapse. They are characterized by fatigable muscle weakness. We performed linkage analysis, whole-exome and whole-genome sequencing to determine the underlying defect in patients with an inherited limb-girdle pattern of myasthenic weakness. We identify ALG14 and ALG2 as novel genes in which mutations cause a congenital myasthenic syndrome. Through analogy with yeast, ALG14 is thought to form a multiglycosyltransferase complex with ALG13 and DPAGT1 that catalyses the first two committed steps of asparagine-linked protein glycosylation. We show that ALG14 is concentrated at the muscle motor endplates and small interfering RNA silencing of ALG14 results in reduced cell-surface expression of muscle acetylcholine receptor expressed in human embryonic kidney 293 cells. ALG2 is an alpha-1,3-mannosyltransferase that also catalyses early steps in the asparagine-linked glycosylation pathway. Mutations were identified in two kinships, with mutation ALG2p.Val68Gly found to severely reduce ALG2 expression both in patient muscle, and in cell cultures. Identification of DPAGT1, ALG14 and ALG2 mutations as a cause of congenital myasthenic syndrome underscores the importance of asparagine-linked protein glycosylation for proper functioning of the neuromuscular junction. These syndromes form part of the wider spectrum of congenital disorders of glycosylation caused by impaired asparagine-linked glycosylation. It is likely that further genes encoding components of this pathway will be associated with congenital myasthenic syndromes or impaired neuromuscular transmission as part of a more severe multisystem disorder. Our findings suggest that treatment with cholinesterase inhibitors may improve muscle function in many of the congenital disorders of glycosylation.
Collapse
Affiliation(s)
- Judith Cossins
- Neurosciences Group, Weatherall Institute of Molecular Medicine, The John Radcliffe, Oxford OX3 9DS, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Takahashi T, Gao XD. Physical Interactions among Human Glycosyltransferases Involved in Dolichol-Linked Oligosaccharide Biosynthesis. TRENDS GLYCOSCI GLYC 2012. [DOI: 10.4052/tigg.24.65] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|