1
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Kelly SD, Duong NH, Nothof JT, Lowary TL, Whitfield C. Three-component systems represent a common pathway for extracytoplasmic addition of pentofuranose sugars into bacterial glycans. Proc Natl Acad Sci U S A 2024; 121:e2402554121. [PMID: 38748580 PMCID: PMC11127046 DOI: 10.1073/pnas.2402554121] [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: 02/05/2024] [Accepted: 04/18/2024] [Indexed: 05/27/2024] Open
Abstract
Cell surface glycans are major drivers of antigenic diversity in bacteria. The biochemistry and molecular biology underpinning their synthesis are important in understanding host-pathogen interactions and for vaccine development with emerging chemoenzymatic and glycoengineering approaches. Structural diversity in glycostructures arises from the action of glycosyltransferases (GTs) that use an immense catalog of activated sugar donors to build the repeating unit and modifying enzymes that add further heterogeneity. Classical Leloir GTs incorporate α- or β-linked sugars by inverting or retaining mechanisms, depending on the nucleotide sugar donor. In contrast, the mechanism of known ribofuranosyltransferases is confined to β-linkages, so the existence of α-linked ribofuranose in some glycans dictates an alternative strategy. Here, we use Citrobacter youngae O1 and O2 lipopolysaccharide O antigens as prototypes to describe a widespread, versatile pathway for incorporating side-chain α-linked pentofuranoses by extracytoplasmic postpolymerization glycosylation. The pathway requires a polyprenyl phosphoribose synthase to generate a lipid-linked donor, a MATE-family flippase to transport the donor to the periplasm, and a GT-C type GT (founding the GT136 family) that performs the final glycosylation reaction. The characterized system shares similarities, but also fundamental differences, with both cell wall arabinan biosynthesis in mycobacteria, and periplasmic glucosylation of O antigens first discovered in Salmonella and Shigella. The participation of auxiliary epimerases allows the diversification of incorporated pentofuranoses. The results offer insight into a broad concept in microbial glycobiology and provide prototype systems and bioinformatic guides that facilitate discovery of further examples from diverse species, some in currently unknown glycans.
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Affiliation(s)
- Steven D. Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Nam Ha Duong
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
- Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, Academia Sinica, Nangang, Taipei11529, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu300044, Taiwan
| | - Jeremy T. Nothof
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
| | - Todd L. Lowary
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
- Institute of Biochemical Sciences, National Taiwan University, Taipei10617, Taiwan
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
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2
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Karas BF, Terez KR, Mowla S, Battula N, Flannery KP, Gural BM, Aboussleman G, Mubin N, Manzini MC. Removal of pomt1 in zebrafish leads to loss of α-dystroglycan glycosylation and dystroglycanopathy phenotypes. Hum Mol Genet 2024; 33:709-723. [PMID: 38272461 PMCID: PMC11000664 DOI: 10.1093/hmg/ddae006] [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: 07/11/2023] [Revised: 11/28/2023] [Accepted: 12/22/2023] [Indexed: 01/27/2024] Open
Abstract
Biallelic mutations in Protein O-mannosyltransferase 1 (POMT1) are among the most common causes of a severe group of congenital muscular dystrophies (CMDs) known as dystroglycanopathies. POMT1 is a glycosyltransferase responsible for the attachment of a functional glycan mediating interactions between the transmembrane glycoprotein dystroglycan and its binding partners in the extracellular matrix (ECM). Disruptions in these cell-ECM interactions lead to multiple developmental defects causing brain and eye malformations in addition to CMD. Removing Pomt1 in the mouse leads to early embryonic death due to the essential role of dystroglycan during placental formation in rodents. Here, we characterized and validated a model of pomt1 loss of function in the zebrafish showing that developmental defects found in individuals affected by dystroglycanopathies can be recapitulated in the fish. We also discovered that pomt1 mRNA provided by the mother in the oocyte supports dystroglycan glycosylation during the first few weeks of development. Muscle disease, retinal synapse formation deficits, and axon guidance defects can only be uncovered during the first week post fertilization by generating knock-out embryos from knock-out mothers. Conversely, maternal pomt1 from heterozygous mothers was sufficient to sustain muscle, eye, and brain development only leading to loss of photoreceptor synapses at 30 days post fertilization. Our findings show that it is important to define the contribution of maternal mRNA while developing zebrafish models of dystroglycanopathies and that offspring generated from heterozygous and knock-out mothers can be used to differentiate the role of dystroglycan glycosylation in tissue formation and maintenance.
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Affiliation(s)
- Brittany F Karas
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers University-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Kristin R Terez
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers University-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Shorbon Mowla
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers University-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Namarata Battula
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers University-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Kyle P Flannery
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers University-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Brian M Gural
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers University-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Grace Aboussleman
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers University-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - Numa Mubin
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers University-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
| | - M Chiara Manzini
- Department of Neuroscience and Cell Biology, Child Health Institute of New Jersey, Rutgers University-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
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3
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Bhattacharje G, Ghosh A, Das AK. Deciphering the mannose transfer mechanism of mycobacterial PimE by molecular dynamics simulations. Glycobiology 2024; 34:cwad096. [PMID: 38039077 DOI: 10.1093/glycob/cwad096] [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: 10/04/2023] [Revised: 11/21/2023] [Accepted: 11/27/2023] [Indexed: 12/03/2023] Open
Abstract
Phosphatidyl-myo-inositol mannosides (PIMs), Lipomannan (LM), and Lipoarabinomannan (LAM) are essential components of the cell envelopes of mycobacteria. At the beginning of the biosynthesis of these compounds, phosphatidylinositol (PI) is mannosylated and acylated by various enzymes to produce Ac1/2PIM4, which is used to synthesize either Ac1/2PIM6 or LM/LAM. The protein PimE, a membrane-bound glycosyltransferase (GT-C), catalyzes the addition of a mannose group to Ac1PIM4 to produce Ac1PIM5, using polyprenolphosphate mannose (PPM) as the mannose donor. PimE-deleted Mycobacterium smegmatis (Msmeg) showed structural deformity and increased antibiotic and copper sensitivity. Despite knowing that the mutation D58A caused inactivity in Msmeg, how PimE catalyzes the transfer of mannose from PPM to Ac1/2PIM4 remains unknown. In this study, analyzing the AlphaFold structure of PimE revealed the presence of a tunnel through the D58 residue with two differently charged gates. Molecular docking suggested PPM binds to the hydrophobic tunnel gate, whereas Ac1PIM4 binds to the positively charged tunnel gate. Molecular dynamics (MD) simulations further demonstrated the critical roles of the residues N55, F87, L89, Y163, Q165, K197, L198, R251, F277, W324, H326, and I375 in binding PPM and Ac1PIM4. The mutation D58A caused a faster release of PPM from the catalytic tunnel, explaining the loss of PimE activity. Along with a hypothetical mechanism of mannose transfer by PimE, we also observe the presence of tunnels through a negatively charged aspartate or glutamate with two differently-charged gates among most GT-C enzymes. Common hydrophobic gates of GT-C enzymes probably harbor sugar donors, whereas, differently-charged tunnel gates accommodate various sugar-acceptors.
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Affiliation(s)
- Gourab Bhattacharje
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Midnapore, WB 721302, India
| | - Amit Ghosh
- School of Energy Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Midnapore, WB 721302, India
| | - Amit Kumar Das
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Midnapore, WB 721302, India
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4
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Géraud N, Falcou C, Parra J, Froment C, Rengel D, Burlet-Schiltz O, Marcoux J, Nigou J, Rivière M, Fabre E. Development of a novel target-based cell assay, reporter of the activity of Mycobacterium tuberculosis protein-O-mannosyltransferase. Glycobiology 2023; 33:1139-1154. [PMID: 37698262 DOI: 10.1093/glycob/cwad072] [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: 07/12/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/13/2023] Open
Abstract
The Protein-O-mannosyltransferase is crucial for the virulence of Mycobacterium tuberculosis, the etiological agent of tuberculosis. This enzyme, called MtPMT (Rv1002c), is responsible for the post-translational O-mannosylation of mycobacterial proteins. It catalyzes the transfer of a single mannose residue from a polyprenol phospho-mannosyl lipidic donor to the hydroxyl groups of selected Ser/Thr residues in acceptor proteins during their translocation across the membrane. Previously, we provided evidence that the loss of MtPMT activity causes the absence of mannoproteins in Mycobacterium tuberculosis, severely impacting its intracellular growth, as well as a strong attenuation of its pathogenicity in immunocompromised mice. Therefore, it is of interest to develop specific inhibitors of this enzyme to better understand mycobacterial infectious diseases. Here we report the development of a "target-based" phenotypic assay for this enzyme, assessing its O-mannosyltransferase activity in bacteria, in the non-pathogenic Mycobacterium smegmatis strain. Robustness of the quantitative contribution of this assay was evaluated by intact protein mass spectrometry, using a panel of control strains, overexpressing the MtPMT gene, carrying different key point-mutations. Then, screening of a limited library of 30 compounds rationally chosen allowed us to identify 2 compounds containing pyrrole analogous rings, as significant inhibitors of MtPMT activity, affecting neither the growth of the mycobacterium nor its secretion of mannoproteins. These molecular cores could therefore serve as scaffold for the design of new pharmaceutical agents that could improve treatment of mycobacterial diseases. We report here the implementation of a miniaturized phenotypic activity assay for a glycosyltransferase of the C superfamily.
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Affiliation(s)
- Nicolas Géraud
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III-Paul Sabatier (UT3), 31400 Toulouse, France
| | - Camille Falcou
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III-Paul Sabatier (UT3), 31400 Toulouse, France
| | - Julien Parra
- Infrastructure nationale de protéomique, ProFI, 205 Rte de Narbonne, 31400 Toulouse, France
| | - Carine Froment
- Infrastructure nationale de protéomique, ProFI, 205 Rte de Narbonne, 31400 Toulouse, France
| | - David Rengel
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III-Paul Sabatier (UT3), 31400 Toulouse, France
| | - Odile Burlet-Schiltz
- Infrastructure nationale de protéomique, ProFI, 205 Rte de Narbonne, 31400 Toulouse, France
| | - Julien Marcoux
- Infrastructure nationale de protéomique, ProFI, 205 Rte de Narbonne, 31400 Toulouse, France
| | - Jérôme Nigou
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III-Paul Sabatier (UT3), 31400 Toulouse, France
| | - Michel Rivière
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III-Paul Sabatier (UT3), 31400 Toulouse, France
| | - Emeline Fabre
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III-Paul Sabatier (UT3), 31400 Toulouse, France
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5
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Koff M, Monagas-Valentin P, Novikov B, Chandel I, Panin V. Protein O-mannosylation: one sugar, several pathways, many functions. Glycobiology 2023; 33:911-926. [PMID: 37565810 PMCID: PMC10859634 DOI: 10.1093/glycob/cwad067] [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: 07/16/2023] [Revised: 07/23/2023] [Accepted: 07/31/2023] [Indexed: 08/12/2023] Open
Abstract
Recent research has unveiled numerous important functions of protein glycosylation in development, homeostasis, and diseases. A type of glycosylation taking the center stage is protein O-mannosylation, a posttranslational modification conserved in a wide range of organisms, from yeast to humans. In animals, protein O-mannosylation plays a crucial role in the nervous system, whereas protein O-mannosylation defects cause severe neurological abnormalities and congenital muscular dystrophies. However, the molecular and cellular mechanisms underlying protein O-mannosylation functions and biosynthesis remain not well understood. This review outlines recent studies on protein O-mannosylation while focusing on the functions in the nervous system, summarizes the current knowledge about protein O-mannosylation biosynthesis, and discusses the pathologies associated with protein O-mannosylation defects. The evolutionary perspective revealed by studies in the Drosophila model system are also highlighted. Finally, the review touches upon important knowledge gaps in the field and discusses critical questions for future research on the molecular and cellular mechanisms associated with protein O-mannosylation functions.
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Affiliation(s)
- Melissa Koff
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
| | - Pedro Monagas-Valentin
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
| | - Boris Novikov
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
| | - Ishita Chandel
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
| | - Vladislav Panin
- Department of Biochemistry and Biophysics, AgriLife Research, Texas A&M University, College Station, College Station, TX 77843, United States
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6
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Larsen ISB, Povolo L, Zhou L, Tian W, Mygind KJ, Hintze J, Jiang C, Hartill V, Prescott K, Johnson CA, Mullegama SV, McConkie-Rosell A, McDonald M, Hansen L, Vakhrushev SY, Schjoldager KT, Clausen H, Worzfeld T, Joshi HJ, Halim A. The SHDRA syndrome-associated gene TMEM260 encodes a protein-specific O-mannosyltransferase. Proc Natl Acad Sci U S A 2023; 120:e2302584120. [PMID: 37186866 PMCID: PMC10214176 DOI: 10.1073/pnas.2302584120] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/21/2023] [Indexed: 05/17/2023] Open
Abstract
Mutations in the TMEM260 gene cause structural heart defects and renal anomalies syndrome, but the function of the encoded protein remains unknown. We previously reported wide occurrence of O-mannose glycans on extracellular immunoglobulin, plexin, transcription factor (IPT) domains found in the hepatocyte growth factor receptor (cMET), macrophage-stimulating protein receptor (RON), and plexin receptors, and further demonstrated that two known protein O-mannosylation systems orchestrated by the POMT1/2 and transmembrane and tetratricopeptide repeat-containing proteins 1-4 gene families were not required for glycosylation of these IPT domains. Here, we report that the TMEM260 gene encodes an ER-located protein O-mannosyltransferase that selectively glycosylates IPT domains. We demonstrate that disease-causing TMEM260 mutations impair O-mannosylation of IPT domains and that TMEM260 knockout in cells results in receptor maturation defects and abnormal growth of 3D cell models. Thus, our study identifies the third protein-specific O-mannosylation pathway in mammals and demonstrates that O-mannosylation of IPT domains serves critical functions during epithelial morphogenesis. Our findings add a new glycosylation pathway and gene to a growing group of congenital disorders of glycosylation.
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Affiliation(s)
- Ida Signe Bohse Larsen
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Lorenzo Povolo
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Luping Zhou
- Faculty of Medicine, Institute of Pharmacology, University of Marburg, 35043Marburg, Germany
| | - Weihua Tian
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Kasper Johansen Mygind
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - John Hintze
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Chen Jiang
- Faculty of Medicine, Institute of Pharmacology, University of Marburg, 35043Marburg, Germany
| | - Verity Hartill
- Leeds Institute of Medical Research, University of Leeds, St James’ University Hospital, LeedsLS2 9JT, United Kingdom
- Yorkshire Regional Genetics Service, Chapel Allerton Hospital, LeedsLS7 4SA, United Kingdom
| | - Katrina Prescott
- Yorkshire Regional Genetics Service, Chapel Allerton Hospital, LeedsLS7 4SA, United Kingdom
| | - Colin A. Johnson
- Leeds Institute of Medical Research, University of Leeds, St James’ University Hospital, LeedsLS2 9JT, United Kingdom
| | | | - Allyn McConkie-Rosell
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC27710
| | - Marie McDonald
- Division of Medical Genetics, Department of Pediatrics, Duke University Medical Center, Durham, NC27710
| | - Lars Hansen
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Sergey Y. Vakhrushev
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Katrine T. Schjoldager
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Henrik Clausen
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Thomas Worzfeld
- Faculty of Medicine, Institute of Pharmacology, University of Marburg, 35043Marburg, Germany
- Max-Planck-Institute for Heart and Lung Research, 61231Bad Nauheim, Germany
| | - Hiren J. Joshi
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
| | - Adnan Halim
- Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200Copenhagen N, Denmark
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7
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Bloch JS, John A, Mao R, Mukherjee S, Boilevin J, Irobalieva RN, Darbre T, Scott NE, Reymond JL, Kossiakoff AA, Goddard-Borger ED, Locher KP. Structure, sequon recognition and mechanism of tryptophan C-mannosyltransferase. Nat Chem Biol 2023; 19:575-584. [PMID: 36604564 PMCID: PMC10154233 DOI: 10.1038/s41589-022-01219-9] [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: 06/22/2022] [Accepted: 10/28/2022] [Indexed: 01/07/2023]
Abstract
C-linked glycosylation is essential for the trafficking, folding and function of secretory and transmembrane proteins involved in cellular communication processes. The tryptophan C-mannosyltransferase (CMT) enzymes that install the modification attach a mannose to the first tryptophan of WxxW/C sequons in nascent polypeptide chains by an unknown mechanism. Here, we report cryogenic-electron microscopy structures of Caenorhabditis elegans CMT in four key states: apo, acceptor peptide-bound, donor-substrate analog-bound and as a trapped ternary complex with both peptide and a donor-substrate mimic bound. The structures indicate how the C-mannosylation sequon is recognized by this CMT and its paralogs, and how sequon binding triggers conformational activation of the donor substrate: a process relevant to all glycosyltransferase C superfamily enzymes. Our structural data further indicate that the CMTs adopt an unprecedented electrophilic aromatic substitution mechanism to enable the C-glycosylation of proteins. These results afford opportunities for understanding human disease and therapeutic targeting of specific CMT paralogs.
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Affiliation(s)
- Joël S Bloch
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland
- Laboratory of Molecular Neurobiology and Biophysics and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Alan John
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Runyu Mao
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Somnath Mukherjee
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Jérémy Boilevin
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | | | - Tamis Darbre
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, Victoria, Australia
| | - Jean-Louis Reymond
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Ethan D Goddard-Borger
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia.
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland.
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8
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Alexander JAN, Locher KP. Emerging structural insights into C-type glycosyltransferases. Curr Opin Struct Biol 2023; 79:102547. [PMID: 36827761 DOI: 10.1016/j.sbi.2023.102547] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 12/19/2022] [Accepted: 01/11/2023] [Indexed: 02/24/2023]
Abstract
Glycosyltransferases of the C superfamily (GT-Cs) are enzymes found in all domains of life. They catalyse the stepwise synthesis of oligosaccharides or the transfer of assembled glycans from lipid-linked donor substrates to acceptor proteins. The processes mediated by GT-Cs are required for C-, N- and O-linked glycosylation, all of which are essential post-translational modifications in higher-order eukaryotes. Until recently, GT-Cs were thought to share a conserved structural module of 7 transmembrane helices; however, recently determined GT-C structures revealed novel folds. Here we analyse the growing diversity of GT-C folds and discuss the emergence of two subclasses, termed GT-CA and GT-CB. Further substrate-bound structures are needed to facilitate a molecular understanding of glycan recognition and catalysis in these two subclasses.
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Affiliation(s)
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland.
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9
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Crine SL, Acharya KR. Molecular basis of C-mannosylation - a structural perspective. FEBS J 2022; 289:7670-7687. [PMID: 34741587 DOI: 10.1111/febs.16265] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 10/22/2021] [Accepted: 11/04/2021] [Indexed: 01/14/2023]
Abstract
The structural and functional diversity of proteins can be enhanced by numerous post-translational modifications. C-mannosylation is a rare form of glycosylation consisting of a single alpha or beta D-mannopyranose forming a carbon-carbon bond with the pyrrole ring of a tryptophan residue. Despite first being discovered in 1994, C-mannosylation is still poorly understood and 3D structures are available for only a fraction of the total predicted C-mannosylated proteins. Here, we present the first comprehensive review of C-mannosylated protein structures by analysing the data for all 10 proteins with C-mannosylation/s deposited in the Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB). We analysed in detail the WXXW/WXXWXXW consensus motif and the highly conserved pair of arginine residues in thrombospondin type 1 repeat C-mannosylation sites or homologous arginine residues in other domains. Furthermore, we identified a conserved PXP sequence C-terminal of the C-mannosylation site. The PXP motif forms a tight turn region in the polypeptide chain and its universal conservation in C-mannosylated protein is worthy of further experimental study. The stabilization of C-mannopyranosyl groups was demonstrated through hydrogen bonding with arginine and other charged or polar amino acids. Where possible, the structural findings were linked to other functional studies demonstrating the role of C-mannosylation in protein stability, secretion or function. With the current technological advances in structural biology, we hope to see more progress in the study of C-mannosylation that may correspond to discoveries of novel C-mannosylation pathways and functions with implications for human health and biotechnology.
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Affiliation(s)
- Samuel L Crine
- Department of Biology and Biochemistry, University of Bath, UK
| | - K Ravi Acharya
- Department of Biology and Biochemistry, University of Bath, UK
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10
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Neuhaus JD, Wild R, Eyring J, Irobalieva RN, Kowal J, Lin CW, Locher KP, Aebi M. Functional analysis of Ost3p and Ost6p containing yeast oligosaccharyltransferases. Glycobiology 2021; 31:1604-1615. [PMID: 34974622 DOI: 10.1093/glycob/cwab084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 07/14/2021] [Accepted: 08/05/2021] [Indexed: 11/14/2022] Open
Abstract
The oligosaccharyltransferase (OST) is the central enzyme in the N-glycosylation pathway. It transfers a defined oligosaccharide from a lipid-linker onto the asparagine side chain of proteins. The yeast OST consists of eight subunits and exists in two catalytically distinct isoforms that differ in one subunit, Ost3p or Ost6p. The cryo-electron microscopy structure of the Ost6p containing complex was found to be highly similar to the Ost3p containing OST. OST enzymes with altered Ost3p/Ost6p subunits were generated and functionally analyzed. The three C-terminal transmembrane helices were responsible for the higher turnover-rate of the Ost3p vs. the Ost6p containing enzyme in vitro and the more severe hypoglycosylation in Ost3p lacking strains in vivo. Glycosylation of specific OST target sites required the N-terminal thioredoxin domain of Ost3p or Ost6p. This Ost3p/Ost6p dependence was glycosylation site but not protein specific. We concluded that the Ost3p/Ost6p subunits modulate the catalytic activity of OST and provide additional specificity for OST substrate recognition.
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Affiliation(s)
- Julia D Neuhaus
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Rebekka Wild
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland.,Institut de Biologie Structurale, CNRS, CEA, Université Grenoble-Alpes, 38000 Grenoble, France
| | - Jillianne Eyring
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Rossitza N Irobalieva
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Julia Kowal
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Chia-Wei Lin
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland.,Functional Genomic Center Zurich, 8057 Zurich, Switzerland
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Markus Aebi
- Institute of Microbiology, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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11
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Holman NDM, Wilkinson AJ, Smith MCM. Alanine-scanning mutagenesis of protein mannosyl-transferase from Streptomyces coelicolor reveals strong activity-stability correlation. MICROBIOLOGY-SGM 2021; 167. [PMID: 34676818 PMCID: PMC8698208 DOI: 10.1099/mic.0.001103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In Actinobacteria, protein O-mannosyl transferase (Pmt)-mediated protein O-glycosylation has an important role in cell envelope physiology. In S. coelicolor, defective Pmt leads to increased susceptibility to cell wall-targeting antibiotics, including vancomycin and β-lactams, and resistance to phage ϕC31. The aim of this study was to gain a deeper understanding of the structure and function of S. coelicolor Pmt. Sequence alignments and structural bioinformatics were used to identify target sites for an alanine-scanning mutagenesis study. Mutant alleles were introduced into pmt-deficient S. coelicolor strains using an integrative plasmid and scored for their ability to complement phage resistance and antibiotic hypersusceptibility phenotypes. Twenty-three highly conserved Pmt residues were each substituted for alanine. Six mutant alleles failed to complement the pmt▬ strains in either assay. Mapping the six corresponding residues onto a homology model of the three-dimensional structure of Pmt, indicated that five are positioned close to the predicted catalytic DE motif. Further mutagenesis to produce more conservative substitutions at these six residues produced Pmts that invariably failed to complement the DT1025 pmt▬ strain, indicating that strict residue conservation was necessary to preserve function. Cell fractionation and Western blotting of strains with the non-complementing pmt alleles revealed undetectable levels of the enzyme in either the membrane fractions or whole cell lysates. Meanwhile for all of the strains that complemented the antibiotic hypersusceptibility and phage resistance phenotypes, Pmt was readily detected in the membrane fraction. These data indicate a tight correlation between the activity of Pmt and its stability or ability to localize to the membrane.
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Affiliation(s)
| | - Anthony J Wilkinson
- Structural Biology Laboratory, York Biomedical Research Institute, Department of Chemistry, University of York, York YO10 5DD, UK
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12
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Role of Protein Glycosylation in Interactions of Medically Relevant Fungi with the Host. J Fungi (Basel) 2021; 7:jof7100875. [PMID: 34682296 PMCID: PMC8541085 DOI: 10.3390/jof7100875] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/08/2021] [Accepted: 10/11/2021] [Indexed: 01/09/2023] Open
Abstract
Protein glycosylation is a highly conserved post-translational modification among organisms. It plays fundamental roles in many biological processes, ranging from protein trafficking and cell adhesion to host–pathogen interactions. According to the amino acid side chain atoms to which glycans are linked, protein glycosylation can be divided into two major categories: N-glycosylation and O-glycosylation. However, there are other types of modifications such as the addition of GPI to the C-terminal end of the protein. Besides the importance of glycoproteins in biological functions, they are a major component of the fungal cell wall and plasma membrane and contribute to pathogenicity, virulence, and recognition by the host immunity. Given that this structure is absent in host mammalian cells, it stands as an attractive target for developing selective compounds for the treatment of fungal infections. This review focuses on describing the relationship between protein glycosylation and the host–immune interaction in medically relevant fungal species.
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13
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The N-mannosyltransferase gene BbAlg9 contributes to cell wall integrity, fungal development and the pathogenicity of Beauveria bassiana. Fungal Biol 2021; 125:776-784. [PMID: 34537173 DOI: 10.1016/j.funbio.2021.04.011] [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: 12/29/2020] [Revised: 04/25/2021] [Accepted: 04/29/2021] [Indexed: 11/22/2022]
Abstract
The mannosyltransferase Alg9 plays a vital role in N-linked protein glycosylation in Saccharomyces cerevisiae, but its function in most filamentous fungi is not clear. The present study characterized BbAlg9 (an ortholog of S. cerevisiae Alg9) in Beauveria bassiana to determine the roles of N-mannosyltransferase in biological control potential of the filamentous entomopathogenic fungus. The disruption of BbAlg9 led to slower fungal growth in media with various nutrition compositions. The conidiation of ΔBbAlg9 was less than that of the wild type from the third to the fifth day but showed no significant difference on the sixth day, suggesting that BbAlg9 affects the development of conidia rather than conidial yield of late stage. ΔBbAlg9 showed defects in conidial germination, multiple stress tolerances and the yield of blastospores, with altered size and density, and virulence in hosts infected via the immersion and injection methods. The deletion of BbAlg9 resulted in defects in cell wall integrity, including increased mannoprotein and glucan content and decreased chitin content, which were accompanied by transcriptional activation or suppression of genes related to cell wall component biosynthesis. Notably, deletion of the N-mannosyltransferase BbAlg9 altered the transcription levels of O-mannosyltransferase genes (Pmt and Ktr family). These data show that BbAlg9 is involved in the fungal development, conidial stress tolerance, cell wall integrity and virulence of B. bassiana.
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14
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Bai L, Li H. Protein N-glycosylation and O-mannosylation are catalyzed by two evolutionarily related GT-C glycosyltransferases. Curr Opin Struct Biol 2021; 68:66-73. [PMID: 33445129 PMCID: PMC8222153 DOI: 10.1016/j.sbi.2020.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/14/2020] [Accepted: 12/23/2020] [Indexed: 11/30/2022]
Abstract
The structural folds of glycosyltransferases are categorized into three superfamilies: GT-A, GT-B, and GT-C. Few structures of GT-C fold existed in the Protein Data Bank prior to the recent advent of high-resolution cryo-EM, because the glycosyltransferases are large membrane proteins that are difficult to crystallize. The use of cryo-EM has resulted in the structures of several key GT-C glycosyltransferases. Here we summarize the latest structural features of and mechanistic insights into these membrane enzyme complexes.
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Affiliation(s)
- Lin Bai
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing 100083, PR China.
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI 49503, United States.
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15
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Pejenaute-Ochoa MD, Santana-Molina C, Devos DP, Ibeas JI, Fernández-Álvarez A. Structural, Evolutionary, and Functional Analysis of the Protein O-Mannosyltransferase Family in Pathogenic Fungi. J Fungi (Basel) 2021; 7:jof7050328. [PMID: 33922798 PMCID: PMC8147084 DOI: 10.3390/jof7050328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 12/27/2022] Open
Abstract
Protein O-mannosyltransferases (Pmts) comprise a group of proteins that add mannoses to substrate proteins at the endoplasmic reticulum. This post-translational modification is important for the faithful transfer of nascent glycoproteins throughout the secretory pathway. Most fungi genomes encode three O-mannosyltransferases, usually named Pmt1, Pmt2, and Pmt4. In pathogenic fungi, Pmts, especially Pmt4, are key factors for virulence. Although the importance of Pmts for fungal pathogenesis is well established in a wide range of pathogens, questions remain regarding certain features of Pmts. For example, why does the single deletion of each pmt gene have an asymmetrical impact on host colonization? Here, we analyse the origin of Pmts in fungi and review the most important phenotypes associated with Pmt mutants in pathogenic fungi. Hence, we highlight the enormous relevance of these glycotransferases for fungal pathogenic development.
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16
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Zhang H, Wang Y, Brunecky R, Yao B, Xie X, Zheng F, Luo H. A Swollenin From Talaromyces leycettanus JCM12802 Enhances Cellulase Hydrolysis Toward Various Substrates. Front Microbiol 2021; 12:658096. [PMID: 33854492 PMCID: PMC8039133 DOI: 10.3389/fmicb.2021.658096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/10/2021] [Indexed: 12/02/2022] Open
Abstract
Swollenins exist within some fungal species and are candidate accessory proteins for the biodegradation of cellulosic substrates. Here, we describe the identification of a swollenin gene, Tlswo, in Talaromyces leycettanus JCM12802. Tlswo was successfully expressed in both Trichoderma reesei and Pichia pastoris. Assay results indicate that TlSWO is capable of releasing reducing sugars from lichenan, barley β-glucan, carboxymethyl cellulose sodium (CMC-Na) and laminarin. The specific activity of TlSWO toward lichenan, barley β-glucan, carboxymethyl cellulose sodium (CMC-Na) and laminarin is 9.0 ± 0.100, 8.9 ± 0.100, 2.3 ± 0.002 and 0.79 ± 0.002 U/mg, respectively. Additionally, TlSWO had disruptive activity on Avicel and a synergistic effect with cellobiohydrolases, increasing the activity on pretreated corn stover by up to 72.2%. The functional diversity of TlSWO broadens its applicability in experimental settings, and indicating that it may be a promising candidate for future industrial applications.
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Affiliation(s)
- Honghai Zhang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuan Wang
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Roman Brunecky
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Bin Yao
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiangming Xie
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Fei Zheng
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Huiying Luo
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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17
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Song D, Dai Y, Chen X, Fu X, Chang X, Wang N, Zhang C, Yan C, Zheng H, Wu L, Jiang L, Hua Y, Yang H, Wang Z, Dai T, Zhu W, Han C, Yuan Y, Kobayashi K, Toda T, Xiong H. Genetic variations and clinical spectrum of dystroglycanopathy in a large cohort of Chinese patients. Clin Genet 2021; 99:384-395. [PMID: 33200426 DOI: 10.1111/cge.13886] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/27/2020] [Accepted: 11/12/2020] [Indexed: 12/18/2022]
Abstract
Dystroglycanopathy is a group of muscular dystrophies with deficient glycosylation of alpha-dystroglycan (α-DG). We recruited patients from 36 tertiary academic hospitals in China. In total, 143 patients with genetically diagnosed dystroglycanopathy were enrolled. Of these, limb girdle muscular dystrophy was the most common initial diagnosis (83 patients) and Walker-Warburg syndrome was the least common (1 patient). In 143 patients, mutations in FKRP gene were the most prevalent (62 patients), followed by POMT2, POMT1 (16), POMGNT1, ISPD (14), FKTN, GMPPB, B3GALNT2, DPM3, and DAG1. Several frequent mutations were identified in FKRP, POMT1, POMGNT1, ISPD, and FKTN genes. Many of these were founder mutations. Patients with FKRP mutations tended to have milder phenotypes, while those with mutations in POMGNT1 genes had more severe phenotypes. Mental retardation was a clinical feature associated with mutations of POMT1 gene. Detailed clinical data of 83 patients followed up in Peking University First Hospital were further analyzed. Our clinical and genetic analysis of a large cohort of Chinese patients with dystroglycanopathy expanded the genotype variation and clinical spectrum of congenital muscular dystrophies.
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Affiliation(s)
- Danyu Song
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yi Dai
- Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Xiaoyu Chen
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiaona Fu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xingzhi Chang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Cheng Zhang
- Department of Neurology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Chuanzhu Yan
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Hong Zheng
- Department of Pediatrics, the First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China
| | - Liwen Wu
- Department of Neurology, Hunan Children's Hospital, Changsha, China
| | - Li Jiang
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Ying Hua
- Department of Neurology, Wuxi Children's Hospital, Wuxi, China
| | - Haipo Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhiqiang Wang
- Department of Neurology and Institute of Neurology, First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Tingjun Dai
- Department of Neurology, Qilu Hospital, Shandong University, Jinan, China
| | - Wenhua Zhu
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Chunxi Han
- Department of Neurology, Shenzhen Children's Hospital, Shenzhen, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Kazuhiro Kobayashi
- Division of Neurology/Molecular Brain Science, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tatsushi Toda
- Department of Neurology, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
| | - Hui Xiong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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18
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Eisenhaber B, Sinha S, Jadalanki CK, Shitov VA, Tan QW, Sirota FL, Eisenhaber F. Conserved sequence motifs in human TMTC1, TMTC2, TMTC3, and TMTC4, new O-mannosyltransferases from the GT-C/PMT clan, are rationalized as ligand binding sites. Biol Direct 2021; 16:4. [PMID: 33436046 PMCID: PMC7801869 DOI: 10.1186/s13062-021-00291-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/04/2021] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND The human proteins TMTC1, TMTC2, TMTC3 and TMTC4 have been experimentally shown to be components of a new O-mannosylation pathway. Their own mannosyl-transferase activity has been suspected but their actual enzymatic potential has not been demonstrated yet. So far, sequence analysis of TMTCs has been compromised by evolutionary sequence divergence within their membrane-embedded N-terminal region, sequence inaccuracies in the protein databases and the difficulty to interpret the large functional variety of known homologous proteins (mostly sugar transferases and some with known 3D structure). RESULTS Evolutionary conserved molecular function among TMTCs is only possible with conserved membrane topology within their membrane-embedded N-terminal regions leading to the placement of homologous long intermittent loops at the same membrane side. Using this criterion, we demonstrate that all TMTCs have 11 transmembrane regions. The sequence segment homologous to Pfam model DUF1736 is actually just a loop between TM7 and TM8 that is located in the ER lumen and that contains a small hydrophobic, but not membrane-embedded helix. Not only do the membrane-embedded N-terminal regions of TMTCs share a common fold and 3D structural similarity with subgroups of GT-C sugar transferases. The conservation of residues critical for catalysis, for binding of a divalent metal ion and of the phosphate group of a lipid-linked sugar moiety throughout enzymatically and structurally well-studied GT-Cs and sequences of TMTCs indicates that TMTCs are actually sugar-transferring enzymes. We present credible 3D structural models of all four TMTCs (derived from their closest known homologues 5ezm/5f15) and find observed conserved sequence motifs rationalized as binding sites for a metal ion and for a dolichyl-phosphate-mannose moiety. CONCLUSIONS With the results from both careful sequence analysis and structural modelling, we can conclusively say that the TMTCs are enzymatically active sugar transferases belonging to the GT-C/PMT superfamily. The DUF1736 segment, the loop between TM7 and TM8, is critical for catalysis and lipid-linked sugar moiety binding. Together with the available indirect experimental data, we conclude that the TMTCs are not only part of an O-mannosylation pathway in the endoplasmic reticulum of upper eukaryotes but, actually, they are the sought mannosyl-transferases.
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Affiliation(s)
- Birgit Eisenhaber
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Republic of Singapore.
- Genome Institute of Singapore (BII), Agency for Science, Technology and Research (A*STAR), 60 Biopolis Street, Singapore, 138672, Republic of Singapore.
| | - Swati Sinha
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Republic of Singapore
| | - Chaitanya K Jadalanki
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Republic of Singapore
| | - Vladimir A Shitov
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Republic of Singapore
- Siberian State Medical University, Moskovskiy Trakt, 2, Tomsk, Tomsk Oblast, 634050, Russia
| | - Qiao Wen Tan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Republic of Singapore
- School of Biological Science (SBS), Nanyang Technological University (NTU), 60 Nanyang Drive, Singapore, 637551, Republic of Singapore
| | - Fernanda L Sirota
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Republic of Singapore
| | - Frank Eisenhaber
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore, 138671, Republic of Singapore.
- Genome Institute of Singapore (BII), Agency for Science, Technology and Research (A*STAR), 60 Biopolis Street, Singapore, 138672, Republic of Singapore.
- School of Biological Science (SBS), Nanyang Technological University (NTU), 60 Nanyang Drive, Singapore, 637551, Republic of Singapore.
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19
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Bohl H, Bai L, Li H. Recent Progress in Structural Studies on the GT-C Superfamily of Protein Glycosyltransferases. Subcell Biochem 2021; 96:259-271. [PMID: 33252732 DOI: 10.1007/978-3-030-58971-4_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Protein glycosylation is an essential covalent modification involved in protein secretion, stability, binding, folding, and activity. One or more sugars may be O-, N-, S-, or C-linked to specific amino acids by glycosyltransferases, which catalyze the transfer of these sugars from a phosphate-containing carrier molecule. Most glycosyltransferases are members of the GT-A, GT-B, or GT-C structural superfamilies. GT-C enzymes are integral membrane proteins that utilize a phospho-isoprenoid carrier for sugar transfer. To-date, two families of GT-Cs involved in protein glycosylation have been structurally characterized: the family represented by PglB, AglB, and Stt3, which catalyzes oligosaccharide transfer to Asn, and the family represented by Pmt1 and Pmt2, which catalyzes mannose transfer to Thr or Ser. This chapter reviews progress made over recent years on the structure and function of these two GT-C families.
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Affiliation(s)
- Heather Bohl
- Structural Biology Program, Van Andel Institute, Grand Rapids, Michigan, 49503, USA
| | - Lin Bai
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, 100083, Beijing, P. R. China
| | - Huilin Li
- Structural Biology Program, Van Andel Institute, Grand Rapids, Michigan, 49503, USA.
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20
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Chiapparino A, Grbavac A, Jonker HR, Hackmann Y, Mortensen S, Zatorska E, Schott A, Stier G, Saxena K, Wild K, Schwalbe H, Strahl S, Sinning I. Functional implications of MIR domains in protein O-mannosylation. eLife 2020; 9:61189. [PMID: 33357379 PMCID: PMC7759382 DOI: 10.7554/elife.61189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/08/2020] [Indexed: 12/13/2022] Open
Abstract
Protein O-mannosyltransferases (PMTs) represent a conserved family of multispanning endoplasmic reticulum membrane proteins involved in glycosylation of S/T-rich protein substrates and unfolded proteins. PMTs work as dimers and contain a luminal MIR domain with a β-trefoil fold, which is susceptive for missense mutations causing α-dystroglycanopathies in humans. Here, we analyze PMT-MIR domains by an integrated structural biology approach using X-ray crystallography and NMR spectroscopy and evaluate their role in PMT function in vivo. We determine Pmt2- and Pmt3-MIR domain structures and identify two conserved mannose-binding sites, which are consistent with general β-trefoil carbohydrate-binding sites (α, β), and also a unique PMT2-subfamily exposed FKR motif. We show that conserved residues in site α influence enzyme processivity of the Pmt1-Pmt2 heterodimer in vivo. Integration of the data into the context of a Pmt1-Pmt2 structure and comparison with homologous β-trefoil – carbohydrate complexes allows for a functional description of MIR domains in protein O-mannosylation.
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Affiliation(s)
| | - Antonija Grbavac
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Hendrik Ra Jonker
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Frankfurt am Main, Germany
| | - Yvonne Hackmann
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Sofia Mortensen
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Ewa Zatorska
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Andrea Schott
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Gunter Stier
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Krishna Saxena
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Frankfurt am Main, Germany
| | - Klemens Wild
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University, Frankfurt am Main, Germany
| | - Sabine Strahl
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
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21
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Bai L, You Q, Jain BK, Duan HD, Kovach A, Graham TR, Li H. Transport mechanism of P4 ATPase phosphatidylcholine flippases. eLife 2020; 9:62163. [PMID: 33320091 PMCID: PMC7773333 DOI: 10.7554/elife.62163] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022] Open
Abstract
The P4 ATPases use ATP hydrolysis to transport large lipid substrates across lipid bilayers. The structures of the endosome- and Golgi-localized phosphatidylserine flippases—such as the yeast Drs2 and human ATP8A1—have recently been reported. However, a substrate-binding site on the cytosolic side has not been found, and the transport mechanisms of P4 ATPases with other substrates are unknown. Here, we report structures of the S. cerevisiae Dnf1–Lem3 and Dnf2–Lem3 complexes. We captured substrate phosphatidylcholine molecules on both the exoplasmic and cytosolic sides and found that they have similar structures. Unexpectedly, Lem3 contributes to substrate binding. The conformational transitions of these phosphatidylcholine transporters match those of the phosphatidylserine transporters, suggesting a conserved mechanism among P4 ATPases. Dnf1/Dnf2 have a unique P domain helix-turn-helix insertion that is important for function. Therefore, P4 ATPases may have retained an overall transport mechanism while evolving distinct features for different lipid substrates.
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Affiliation(s)
- Lin Bai
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Qinglong You
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Bhawik K Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - H Diessel Duan
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Amanda Kovach
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
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22
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Ninagawa S, George G, Mori K. Mechanisms of productive folding and endoplasmic reticulum-associated degradation of glycoproteins and non-glycoproteins. Biochim Biophys Acta Gen Subj 2020; 1865:129812. [PMID: 33316349 DOI: 10.1016/j.bbagen.2020.129812] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND The quality of proteins destined for the secretory pathway is ensured by two distinct mechanisms in the endoplasmic reticulum (ER): productive folding of newly synthesized proteins, which is assisted by ER-localized molecular chaperones and in most cases also by disulfide bond formation and transfer of an oligosaccharide unit; and ER-associated degradation (ERAD), in which proteins unfolded or misfolded in the ER are recognized and processed for delivery to the ER membrane complex, retrotranslocated through the complex with simultaneous ubiquitination, extracted by AAA-ATPase to the cytosol, and finally degraded by the proteasome. SCOPE OF REVIEW We describe the mechanisms of productive folding and ERAD, with particular attention to glycoproteins versus non-glycoproteins, and to yeast versus mammalian systems. MAJOR CONCLUSION Molecular mechanisms of the productive folding of glycoproteins and non-glycoproteins mediated by molecular chaperones and protein disulfide isomerases are well conserved from yeast to mammals. Additionally, mammals have gained an oligosaccharide structure-dependent folding cycle for glycoproteins. The molecular mechanisms of ERAD are also well conserved from yeast to mammals, but redundant expression of yeast orthologues in mammals has been encountered, particularly for components involved in recognition and processing of glycoproteins and components of the ER membrane complex involved in retrotranslocation and simultaneous ubiquitination of glycoproteins and non-glycoproteins. This may reflect an evolutionary consequence of increasing quantity or quality needs toward mammals. GENERAL SIGNIFICANCE The introduction of innovative genome editing technology into analysis of the mechanisms of mammalian ERAD, as exemplified here, will provide new insights into the pathogenesis of various diseases.
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Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| | - Ginto George
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
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23
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Buljan M, Ciuffa R, van Drogen A, Vichalkovski A, Mehnert M, Rosenberger G, Lee S, Varjosalo M, Pernas LE, Spegg V, Snijder B, Aebersold R, Gstaiger M. Kinase Interaction Network Expands Functional and Disease Roles of Human Kinases. Mol Cell 2020; 79:504-520.e9. [PMID: 32707033 PMCID: PMC7427327 DOI: 10.1016/j.molcel.2020.07.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 02/14/2020] [Accepted: 06/30/2020] [Indexed: 12/30/2022]
Abstract
Protein kinases are essential for signal transduction and control of most cellular processes, including metabolism, membrane transport, motility, and cell cycle. Despite the critical role of kinases in cells and their strong association with diseases, good coverage of their interactions is available for only a fraction of the 535 human kinases. Here, we present a comprehensive mass-spectrometry-based analysis of a human kinase interaction network covering more than 300 kinases. The interaction dataset is a high-quality resource with more than 5,000 previously unreported interactions. We extensively characterized the obtained network and were able to identify previously described, as well as predict new, kinase functional associations, including those of the less well-studied kinases PIM3 and protein O-mannose kinase (POMK). Importantly, the presented interaction map is a valuable resource for assisting biomedical studies. We uncover dozens of kinase-disease associations spanning from genetic disorders to complex diseases, including cancer.
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Affiliation(s)
- Marija Buljan
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, 9014 St. Gallen, Switzerland
| | - Rodolfo Ciuffa
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Audrey van Drogen
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Anton Vichalkovski
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Martin Mehnert
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - George Rosenberger
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland; Columbia University Department of Systems Biology, New York, NY 10032, USA
| | - Sohyon Lee
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Lucia Espona Pernas
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, 8057 Zurich, Switzerland
| | - Berend Snijder
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ruedi Aebersold
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland; Faculty of Science, University of Zurich, Zurich, Switzerland.
| | - Matthias Gstaiger
- Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland.
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24
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Tan YZ, Rodrigues J, Keener JE, Zheng RB, Brunton R, Kloss B, Giacometti SI, Rosário AL, Zhang L, Niederweis M, Clarke OB, Lowary TL, Marty MT, Archer M, Potter CS, Carragher B, Mancia F. Cryo-EM structure of arabinosyltransferase EmbB from Mycobacterium smegmatis. Nat Commun 2020; 11:3396. [PMID: 32636380 PMCID: PMC7341804 DOI: 10.1038/s41467-020-17202-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/18/2020] [Indexed: 01/21/2023] Open
Abstract
Arabinosyltransferase B (EmbB) belongs to a family of membrane-bound glycosyltransferases that build the lipidated polysaccharides of the mycobacterial cell envelope, and are targets of anti-tuberculosis drug ethambutol. We present the 3.3 Å resolution single-particle cryo-electron microscopy structure of Mycobacterium smegmatis EmbB, providing insights on substrate binding and reaction mechanism. Mutations that confer ethambutol resistance map mostly around the putative active site, suggesting this to be the location of drug binding.
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Affiliation(s)
- Yong Zi Tan
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, 10032, USA
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027, USA
| | - José Rodrigues
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157, Oeiras, Portugal
| | - James E Keener
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA
| | - Ruixiang Blake Zheng
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Richard Brunton
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Brian Kloss
- Center on Membrane Protein Production and Analysis, New York Structural Biology Center, New York, NY, 10027, USA
| | - Sabrina I Giacometti
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Ana L Rosário
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157, Oeiras, Portugal
| | - Lei Zhang
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, 10032, USA
- Department of Anesthesiology, Columbia University, New York, NY, 10032, USA
| | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
- Institute of Biological Chemistry, Academia Sinica, Academia Road, Section 2, #128, Nangang, Taipei, 11529, Taiwan
| | - Michael T Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA
- Bio5 Institute, University of Arizona, Tucson, AZ, 85721, USA
| | - Margarida Archer
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157, Oeiras, Portugal
| | - Clinton S Potter
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027, USA
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Bridget Carragher
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027, USA.
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, 10027, USA.
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, 10032, USA.
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, 10032, USA.
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25
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Tan YZ, Zhang L, Rodrigues J, Zheng RB, Giacometti SI, Rosário AL, Kloss B, Dandey VP, Wei H, Brunton R, Raczkowski AM, Athayde D, Catalão MJ, Pimentel M, Clarke OB, Lowary TL, Archer M, Niederweis M, Potter CS, Carragher B, Mancia F. Cryo-EM Structures and Regulation of Arabinofuranosyltransferase AftD from Mycobacteria. Mol Cell 2020; 78:683-699.e11. [PMID: 32386575 PMCID: PMC7263364 DOI: 10.1016/j.molcel.2020.04.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/21/2020] [Accepted: 04/13/2020] [Indexed: 01/21/2023]
Abstract
Mycobacterium tuberculosis causes tuberculosis, a disease that kills over 1 million people each year. Its cell envelope is a common antibiotic target and has a unique structure due, in part, to two lipidated polysaccharides-arabinogalactan and lipoarabinomannan. Arabinofuranosyltransferase D (AftD) is an essential enzyme involved in assembling these glycolipids. We present the 2.9-Å resolution structure of M. abscessus AftD, determined by single-particle cryo-electron microscopy. AftD has a conserved GT-C glycosyltransferase fold and three carbohydrate-binding modules. Glycan array analysis shows that AftD binds complex arabinose glycans. Additionally, AftD is non-covalently complexed with an acyl carrier protein (ACP). 3.4- and 3.5-Å structures of a mutant with impaired ACP binding reveal a conformational change, suggesting that ACP may regulate AftD function. Mutagenesis experiments using a conditional knockout constructed in M. smegmatis confirm the essentiality of the putative active site and the ACP binding for AftD function.
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Affiliation(s)
- Yong Zi Tan
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Lei Zhang
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - José Rodrigues
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | | | - Sabrina I Giacometti
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Ana L Rosário
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Brian Kloss
- Center on Membrane Protein Production and Analysis, New York Structural Biology Center, New York, NY 10027, USA
| | - Venkata P Dandey
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Hui Wei
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Richard Brunton
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Ashleigh M Raczkowski
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Diogo Athayde
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Maria João Catalão
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Madalena Pimentel
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA; Department of Anesthesiology, Columbia University, New York, NY 10032, USA
| | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; Institute of Biological Chemistry, Academia Sinica, Academia Road, Section 2, #128 Nangang, Taipei 11529, Taiwan
| | - Margarida Archer
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Clinton S Potter
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Bridget Carragher
- National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA.
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26
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Zhang L, Zhao Y, Gao Y, Wu L, Gao R, Zhang Q, Wang Y, Wu C, Wu F, Gurcha SS, Veerapen N, Batt SM, Zhao W, Qin L, Yang X, Wang M, Zhu Y, Zhang B, Bi L, Zhang X, Yang H, Guddat LW, Xu W, Wang Q, Li J, Besra GS, Rao Z. Structures of cell wall arabinosyltransferases with the anti-tuberculosis drug ethambutol. Science 2020; 368:1211-1219. [PMID: 32327601 DOI: 10.1126/science.aba9102] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/06/2020] [Accepted: 04/14/2020] [Indexed: 11/02/2022]
Abstract
The arabinosyltransferases EmbA, EmbB, and EmbC are involved in Mycobacterium tuberculosis cell wall synthesis and are recognized as targets for the anti-tuberculosis drug ethambutol. In this study, we determined cryo-electron microscopy and x-ray crystal structures of mycobacterial EmbA-EmbB and EmbC-EmbC complexes in the presence of their glycosyl donor and acceptor substrates and with ethambutol. These structures show how the donor and acceptor substrates bind in the active site and how ethambutol inhibits arabinosyltransferases by binding to the same site as both substrates in EmbB and EmbC. Most drug-resistant mutations are located near the ethambutol binding site. Collectively, our work provides a structural basis for understanding the biochemical function and inhibition of arabinosyltransferases and the development of new anti-tuberculosis agents.
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Affiliation(s)
- Lu Zhang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.,State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Response, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin 300353, China
| | - Yao Zhao
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.,CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 200031, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Yan Gao
- Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China
| | - Lijie Wu
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ruogu Gao
- University of Chinese Academy of Sciences, Beijing 100101, China.,National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
| | - Qi Zhang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yinan Wang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Chengyao Wu
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Fangyu Wu
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Response, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin 300353, China
| | - Sudagar S Gurcha
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Natacha Veerapen
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Sarah M Batt
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Wei Zhao
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Response, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin 300353, China
| | - Ling Qin
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xiuna Yang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Manfu Wang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yan Zhu
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Bing Zhang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Lijun Bi
- National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
| | - Xian'en Zhang
- National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
| | - Haitao Yang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Luke W Guddat
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Wenqing Xu
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Quan Wang
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China. .,National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
| | - Jun Li
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
| | - Gurdyal S Besra
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
| | - Zihe Rao
- Shanghai Institute for Advanced Immunochemical Studies, iHuman Institute, School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China. .,State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Response, College of Life Sciences, College of Pharmacy, Nankai University, Tianjin 300353, China.,Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China.,National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, CAS, Beijing 100101, China
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27
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Structure and mechanism of the ER-based glucosyltransferase ALG6. Nature 2020; 579:443-447. [PMID: 32103179 DOI: 10.1038/s41586-020-2044-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 01/06/2020] [Indexed: 01/03/2023]
Abstract
In eukaryotic protein N-glycosylation, a series of glycosyltransferases catalyse the biosynthesis of a dolichylpyrophosphate-linked oligosaccharide before its transfer onto acceptor proteins1. The final seven steps occur in the lumen of the endoplasmic reticulum (ER) and require dolichylphosphate-activated mannose and glucose as donor substrates2. The responsible enzymes-ALG3, ALG9, ALG12, ALG6, ALG8 and ALG10-are glycosyltransferases of the C-superfamily (GT-Cs), which are loosely defined as containing membrane-spanning helices and processing an isoprenoid-linked carbohydrate donor substrate3,4. Here we present the cryo-electron microscopy structure of yeast ALG6 at 3.0 Å resolution, which reveals a previously undescribed transmembrane protein fold. Comparison with reported GT-C structures suggests that GT-C enzymes contain a modular architecture with a conserved module and a variable module, each with distinct functional roles. We used synthetic analogues of dolichylphosphate-linked and dolichylpyrophosphate-linked sugars and enzymatic glycan extension to generate donor and acceptor substrates using purified enzymes of the ALG pathway to recapitulate the activity of ALG6 in vitro. A second cryo-electron microscopy structure of ALG6 bound to an analogue of dolichylphosphate-glucose at 3.9 Å resolution revealed the active site of the enzyme. Functional analysis of ALG6 variants identified a catalytic aspartate residue that probably acts as a general base. This residue is conserved in the GT-C superfamily. Our results define the architecture of ER-luminal GT-C enzymes and provide a structural basis for understanding their catalytic mechanisms.
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28
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Graham JB, Sunryd JC, Mathavan K, Weir E, Larsen ISB, Halim A, Clausen H, Cousin H, Alfandari D, Hebert DN. Endoplasmic reticulum transmembrane protein TMTC3 contributes to O-mannosylation of E-cadherin, cellular adherence, and embryonic gastrulation. Mol Biol Cell 2020; 31:167-183. [PMID: 31851597 PMCID: PMC7001481 DOI: 10.1091/mbc.e19-07-0408] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/29/2019] [Accepted: 12/12/2019] [Indexed: 01/17/2023] Open
Abstract
Protein glycosylation plays essential roles in protein structure, stability, and activity such as cell adhesion. The cadherin superfamily of adhesion molecules carry O-linked mannose glycans at conserved sites and it was recently demonstrated that the transmembrane and tetratricopeptide repeat-containing proteins 1-4 (TMTC1-4) gene products contribute to the addition of these O-linked mannoses. Here, biochemical, cell biological, and organismal analysis was used to determine that TMTC3 supports the O-mannosylation of E-cadherin, cellular adhesion, and embryonic gastrulation. Using genetically engineered cells lacking all four TMTC genes, overexpression of TMTC3 rescued O-linked glycosylation of E-cadherin and cell adherence. The knockdown of the Tmtcs in Xenopus laevis embryos caused a delay in gastrulation that was rescued by the addition of human TMTC3. Mutations in TMTC3 have been linked to neuronal cell migration diseases including Cobblestone lissencephaly. Analysis of TMTC3 mutations associated with Cobblestone lissencephaly found that three of the variants exhibit reduced stability and missence mutations were unable to complement TMTC3 rescue of gastrulation in Xenopus embryo development. Our study demonstrates that TMTC3 regulates O-linked glycosylation and cadherin-mediated adherence, providing insight into its effect on cellular adherence and migration, as well the basis of TMTC3-associated Cobblestone lissencephaly.
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Affiliation(s)
- Jill B. Graham
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
| | - Johan C. Sunryd
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
| | - Ketan Mathavan
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Amherst, MA 01003
| | - Emma Weir
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Amherst, MA 01003
| | - Ida Signe Bohse Larsen
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen 2200, Denmark
- Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen 2200, Denmark
| | - Adnan Halim
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen 2200, Denmark
- Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen 2200, Denmark
| | - Henrik Clausen
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen 2200, Denmark
- Copenhagen Center for Glycomics, University of Copenhagen, Copenhagen 2200, Denmark
| | - Hélène Cousin
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Amherst, MA 01003
| | - Dominque Alfandari
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Amherst, MA 01003
| | - Daniel N. Hebert
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Amherst, MA 01003
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29
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Ramírez AS, Kowal J, Locher KP. Cryo–electron microscopy structures of human oligosaccharyltransferase complexes OST-A and OST-B. Science 2019; 366:1372-1375. [DOI: 10.1126/science.aaz3505] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/13/2019] [Indexed: 12/22/2022]
Abstract
Oligosaccharyltransferase (OST) catalyzes the transfer of a high-mannose glycan onto secretory proteins in the endoplasmic reticulum. Mammals express two distinct OST complexes that act in a cotranslational (OST-A) or posttranslocational (OST-B) manner. Here, we present high-resolution cryo–electron microscopy structures of human OST-A and OST-B. Although they have similar overall architectures, structural differences in the catalytic subunits STT3A and STT3B facilitate contacts to distinct OST subunits, DC2 in OST-A and MAGT1 in OST-B. In OST-A, interactions with TMEM258 and STT3A allow ribophorin-I to form a four-helix bundle that can bind to a translating ribosome, whereas the equivalent region is disordered in OST-B. We observed an acceptor peptide and dolichylphosphate bound to STT3B, but only dolichylphosphate in STT3A, suggesting distinct affinities of the two OST complexes for protein substrates.
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Affiliation(s)
- Ana S. Ramírez
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Julia Kowal
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Kaspar P. Locher
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
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Albuquerque-Wendt A, Hütte HJ, Buettner FFR, Routier FH, Bakker H. Membrane Topological Model of Glycosyltransferases of the GT-C Superfamily. Int J Mol Sci 2019; 20:ijms20194842. [PMID: 31569500 PMCID: PMC6801728 DOI: 10.3390/ijms20194842] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/24/2019] [Accepted: 09/25/2019] [Indexed: 12/12/2022] Open
Abstract
Glycosyltransferases that use polyisoprenol-linked donor substrates are categorized in the GT-C superfamily. In eukaryotes, they act in the endoplasmic reticulum (ER) lumen and are involved in N-glycosylation, glypiation, O-mannosylation, and C-mannosylation of proteins. We generated a membrane topology model of C-mannosyltransferases (DPY19 family) that concurred perfectly with the 13 transmembrane domains (TMDs) observed in oligosaccharyltransferases (STT3 family) structures. A multiple alignment of family members from diverse organisms highlighted the presence of only a few conserved amino acids between DPY19s and STT3s. Most of these residues were shown to be essential for DPY19 function and are positioned in luminal loops that showed high conservation within the DPY19 family. Multiple alignments of other eukaryotic GT-C families underlined the presence of similar conserved motifs in luminal loops, in all enzymes of the superfamily. Most GT-C enzymes are proposed to have an uneven number of TDMs with 11 (POMT, TMTC, ALG9, ALG12, PIGB, PIGV, and PIGZ) or 13 (DPY19, STT3, and ALG10) membrane-spanning helices. In contrast, PIGM, ALG3, ALG6, and ALG8 have 12 or 14 TMDs and display a C-terminal dilysine ER-retrieval motif oriented towards the cytoplasm. We propose that all members of the GT-C superfamily are evolutionary related enzymes with preserved membrane topology.
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Affiliation(s)
| | - Hermann J Hütte
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany.
| | - Falk F R Buettner
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany.
| | - Françoise H Routier
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany.
| | - Hans Bakker
- Institute of Clinical Biochemistry, Hannover Medical School, 30625 Hannover, Germany.
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