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Elziny S, Crino PB, Winawer M. SLC35A2 somatic variants in drug resistant epilepsy: FCD and MOGHE. Neurobiol Dis 2023; 187:106299. [PMID: 37739137 PMCID: PMC10994450 DOI: 10.1016/j.nbd.2023.106299] [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: 04/30/2023] [Revised: 09/05/2023] [Accepted: 09/13/2023] [Indexed: 09/24/2023] Open
Abstract
De novo somatic (post-zygotic) gene mutations affecting neuroglial progenitor cell types in embryonic cerebral cortex are increasingly identified in patients with drug resistant epilepsy (DRE) associated with malformations of cortical development, in particular, focal cortical dysplasias (FCD). Somatic variants in at least 16 genes have been linked to FCD type II, all encoding components of the mechanistic target of rapamycin (mTOR) pathway. FCD type II is characterized histopathologically by cytomegalic dysmorphic neurons and balloon cells. In contrast, the molecular pathogenesis of FCD I subtypes is less well understood, and histological features are characterized by alterations in columnar or laminar organization without cytomegalic dysmorphic neurons or balloon cells. In 2018, we reported somatic mutations in Solute Carrier Family 35 member A2 (SLC35A2) linked to DRE underlying FCD type I and subsequently to a new histopathological phenotype: excess oligodendrocytes and heterotopic neurons in subcortical white matter known as MOGHE (mild malformation of cortical development with oligodendroglial hyperplasia). These discoveries opened the door to studies linking somatic mutations to FCD. In this review, we discuss the biology of SLC35A2 somatic mutations in epilepsy in FCD and MOGHE, and insights into SLC35A2 epilepsy pathogenesis, describing progress to date and critical areas for investigation.
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Affiliation(s)
- Soad Elziny
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Melodie Winawer
- Department of Neurology, Columbia University, New York, NY, United States of America.
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2
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Wiertelak W, Pavlovskyi A, Maszczak-Seneczko D, Szulc B, Olczak M. The glycosylation defect in solute carrier SLC35A2/SLC35A3 double knockout cells is rescued by SLC35A2-SLC35A3 and SLC35A3-SLC35A2 hybrids. FEBS Lett 2023; 597:2345-2357. [PMID: 37552213 DOI: 10.1002/1873-3468.14714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/29/2023] [Accepted: 07/31/2023] [Indexed: 08/09/2023]
Abstract
SLC35A2 and SLC35A3 are homologous proteins with postulated nucleotide sugar transporting activities. Unlike SLC35A2, whose specificity for UDP-Gal is well-established, the UDP-GlcNAc transporting activity initially attributed to SLC35A3 has recently been put into question. In this study, we constructed two hybrid proteins (SLC35A2-SLC35A3 and SLC35A3-SLC35A2) and expressed them in a previously generated SLC35A2/SLC35A3 double knockout HEK293T cell line. Our idea was to force equivalent stoichiometry of the two proteins in the cells in order to reproduce the behavior of the SLC35A2/SLC35A3 complexes in the Golgi membrane. The hybrid proteins were able to fully restore glycosylation in the double knockout. In contrast, the expression of SLC35A3 alone in these cells improved galactosylation only to a limited extent. Our study shows that the proper glycosylation requires a balanced cooperation between SLC35A2 and SLC35A3.
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Affiliation(s)
- Wojciech Wiertelak
- Department of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Poland
| | - Artem Pavlovskyi
- Department of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Poland
| | | | - Bożena Szulc
- Department of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Poland
| | - Mariusz Olczak
- Department of Biochemistry, Faculty of Biotechnology, University of Wroclaw, Poland
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3
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Saito S, Mizumoto S, Yonekura T, Yamashita R, Nakano K, Okubo T, Yamada S, Okamura T, Furuichi T. Mice lacking nucleotide sugar transporter SLC35A3 exhibit lethal chondrodysplasia with vertebral anomalies and impaired glycosaminoglycan biosynthesis. PLoS One 2023; 18:e0284292. [PMID: 37053259 PMCID: PMC10101523 DOI: 10.1371/journal.pone.0284292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/28/2023] [Indexed: 04/14/2023] Open
Abstract
SLC35A3 is considered an uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) transporter in mammals and regulates the branching of N-glycans. A missense mutation in SLC35A3 causes complex vertebral malformation (CVM) in cattle. However, the biological functions of SLC35A3 have not been fully clarified. To address these issues, we have established Slc35a3-/-mice using CRISPR/Cas9 genome editing system. The generated mutant mice were perinatal lethal and exhibited chondrodysplasia recapitulating CVM-like vertebral anomalies. During embryogenesis, Slc35a3 mRNA was expressed in the presomitic mesoderm of wild-type mice, suggesting that SLC35A3 transports UDP-GlcNAc used for the sugar modification that is essential for somite formation. In the growth plate cartilage of Slc35a3-/-embryos, extracellular space was drastically reduced, and many flat proliferative chondrocytes were reshaped. Proliferation, apoptosis and differentiation were not affected in the chondrocytes of Slc35a3-/-mice, suggesting that the chondrodysplasia phenotypes were mainly caused by the abnormal extracellular matrix quality. Because these histological abnormalities were similar to those observed in several mutant mice accompanying the impaired glycosaminoglycan (GAG) biosynthesis, GAG levels were measured in the spine and limbs of Slc35a3-/-mice using disaccharide composition analysis. Compared with control mice, the amounts of heparan sulfate, keratan sulfate, and chondroitin sulfate/dermatan sulfate, were significantly decreased in Slc35a3-/-mice. These findings suggest that SLC35A3 regulates GAG biosynthesis and the chondrodysplasia phenotypes were partially caused by the decreased GAG synthesis. Hence, Slc35a3-/- mice would be a useful model for investigating the in vivo roles of SLC35A3 and the pathological mechanisms of SLC35A3-associated diseases.
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Affiliation(s)
- Soichiro Saito
- Laboratory of Laboratory Animal Science and Medicine, Co-Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Aichi, Japan
| | - Tsukasa Yonekura
- Laboratory of Laboratory Animal Science and Medicine, Co-Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Rina Yamashita
- Laboratory of Laboratory Animal Science and Medicine, Co-Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
| | - Kenta Nakano
- Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine (NCGM), Shinjuku-ku, Tokyo, Japan
| | - Tadashi Okubo
- Department of Laboratory Animal Science, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Aichi, Japan
| | - Tadashi Okamura
- Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine (NCGM), Shinjuku-ku, Tokyo, Japan
| | - Tatsuya Furuichi
- Laboratory of Laboratory Animal Science and Medicine, Co-Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan
- Laboratory of Laboratory Animal Science and Medicine, Graduate School of Veterinary Sciences, Iwate University, Morioka, Iwate, Japan
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Delivery of Nucleotide Sugars to the Mammalian Golgi: A Very Well (un)Explained Story. Int J Mol Sci 2022; 23:ijms23158648. [PMID: 35955785 PMCID: PMC9368800 DOI: 10.3390/ijms23158648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/31/2022] [Accepted: 08/02/2022] [Indexed: 11/25/2022] Open
Abstract
Nucleotide sugars (NSs) serve as substrates for glycosylation reactions. The majority of these compounds are synthesized in the cytoplasm, whereas glycosylation occurs in the endoplasmic reticulum (ER) and Golgi lumens, where catalytic domains of glycosyltransferases (GTs) are located. Therefore, translocation of NS across the organelle membranes is a prerequisite. This process is thought to be mediated by a group of multi-transmembrane proteins from the SLC35 family, i.e., nucleotide sugar transporters (NSTs). Despite many years of research, some uncertainties/inconsistencies related with the mechanisms of NS transport and the substrate specificities of NSTs remain. Here we present a comprehensive review of the NS import into the mammalian Golgi, which consists of three major parts. In the first part, we provide a historical view of the experimental approaches used to study NS transport and evaluate the most important achievements. The second part summarizes various aspects of knowledge concerning NSTs, ranging from subcellular localization up to the pathologies related with their defective function. In the third part, we present the outcomes of our research performed using mammalian cell-based models and discuss its relevance in relation to the general context.
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SLC35A2-CDG: Novel variant and review. Mol Genet Metab Rep 2021; 26:100717. [PMID: 33552911 PMCID: PMC7851840 DOI: 10.1016/j.ymgmr.2021.100717] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/17/2021] [Accepted: 01/18/2021] [Indexed: 12/11/2022] Open
Abstract
SLC35A2 encodes the X-linked transporter that carries uridine diphosphate (UDP)-galactose from the cytosol to the lumen of the Golgi apparatus and the endoplasmic reticulum. Pathogenic variants have been associated to a congenital disorder of glycosylation (CDG) with epileptic encephalopathy as a predominant feature. Among the sixty five patients described so far, a strong gender bias is observed as only seven patients are males. This work is a review and reports a SLC35A2-CDG in a male without epilepsy and with growth deficiency associated with decreased serum IGF1, minor neurological involvement, minor facial dysmorphism, and camptodactyly of fingers and toes. Sequence analysis revealed a hemizygosity for a novel de novo variant: c.233A > G (p.Lys78Arg) in SLC35A2. Further analysis of SLC35A2 sequence by comparing both orthologous and paralogous positions, revealed that not only the variant found in this study, but also most of the reported mutated positions are conserved in SLC35A2 orthologous, and many even in the paralogous SLC35A1 and SLC35A3. This is strong evidence that replacements at these positions will have a critical pathological effect and may also explain the gender bias observed among SLC35A2-CDG patients.
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Szulc B, Sosicka P, Maszczak-Seneczko D, Skurska E, Shauchuk A, Olczak T, Freeze HH, Olczak M. Biosynthesis of GlcNAc-rich N- and O-glycans in the Golgi apparatus does not require the nucleotide sugar transporter SLC35A3. J Biol Chem 2020; 295:16445-16463. [PMID: 32938718 DOI: 10.1074/jbc.ra119.012362] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 09/01/2020] [Indexed: 12/31/2022] Open
Abstract
Nucleotide sugar transporters, encoded by the SLC35 gene family, deliver nucleotide sugars throughout the cell for various glycosyltransferase-catalyzed glycosylation reactions. GlcNAc, in the form of UDP-GlcNAc, and galactose, as UDP-Gal, are delivered into the Golgi apparatus by SLC35A3 and SLC35A2 transporters, respectively. However, although the UDP-Gal transporting activity of SLC35A2 has been clearly demonstrated, UDP-GlcNAc delivery by SLC35A3 is not fully understood. Therefore, we analyzed a panel of CHO, HEK293T, and HepG2 cell lines including WT cells, SLC35A2 knockouts, SLC35A3 knockouts, and double-knockout cells. Cells lacking SLC35A2 displayed significant changes in N- and O-glycan synthesis. However, in SLC35A3-knockout CHO cells, only limited changes were observed; GlcNAc was still incorporated into N-glycans, but complex type N-glycan branching was impaired, although UDP-GlcNAc transport into Golgi vesicles was not decreased. In SLC35A3-knockout HEK293T cells, UDP-GlcNAc transport was significantly decreased but not completely abolished. However, N-glycan branching was not impaired in these cells. In CHO and HEK293T cells, the effect of SLC35A3 deficiency on N-glycan branching was potentiated in the absence of SLC35A2. Moreover, in SLC35A3-knockout HEK293T and HepG2 cells, GlcNAc was still incorporated into O-glycans. However, in the case of HepG2 cells, no qualitative changes in N-glycans between WT and SLC35A3 knockout cells nor between SLC35A2 knockout and double-knockout cells were observed. These findings suggest that SLC35A3 may not be the primary UDP-GlcNAc transporter and/or different mechanisms of UDP-GlcNAc transport into the Golgi apparatus may exist.
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Affiliation(s)
- Bozena Szulc
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Paulina Sosicka
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland; Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | | | - Edyta Skurska
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Auhen Shauchuk
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Teresa Olczak
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Hudson H Freeze
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Mariusz Olczak
- Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland.
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7
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Vals MA, Ashikov A, Ilves P, Loorits D, Zeng Q, Barone R, Huijben K, Sykut-Cegielska J, Diogo L, Elias AF, Greenwood RS, Grunewald S, van Hasselt PM, van de Kamp JM, Mancini G, Okninska A, Pajusalu S, Rudd PM, Rustad CF, Salvarinova R, de Vries BBA, Wolf NI, Ng BG, Freeze HH, Lefeber DJ, Õunap K. Clinical, neuroradiological, and biochemical features of SLC35A2-CDG patients. J Inherit Metab Dis 2019; 42:553-564. [PMID: 30746764 DOI: 10.1002/jimd.12055] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 11/14/2018] [Accepted: 11/19/2018] [Indexed: 11/10/2022]
Abstract
SLC35A2-CDG is caused by mutations in the X-linked SLC35A2 gene encoding the UDP-galactose transporter. SLC35A2 mutations lead to hypogalactosylation of N-glycans. SLC35A2-CDG is characterized by severe neurological symptoms and, in many patients, early-onset epileptic encephalopathy. In view of the diagnostic challenges, we studied the clinical, neuroradiological, and biochemical features of 15 patients (11 females and 4 males) with SLC35A2-CDG from various centers. We describe nine novel pathogenic variations in SLC35A2. All affected individuals presented with a global developmental delay, and hypotonia, while 70% were nonambulatory. Epilepsy was present in 80% of the patients, and in EEG hypsarrhythmia and findings consistent with epileptic encephalopathy were frequently seen. The most common brain MRI abnormality was cerebral atrophy with delayed myelination and multifocal inhomogeneous abnormal patchy white matter hyperintensities, which seemed to be nonprogressive. Thin corpus callosum was also common, and all the patients had a corpus callosum shorter than normal for their age. Variable dysmorphic features and growth deficiency were noted. Biochemically, normal mucin type O-glycosylation and lipid glycosylation were found, while transferrin mass spectrometry was found to be more specific in the identification of SLC35A2-CDG, as compared to routine screening tests. Although normal glycosylation studies together with clinical variability and genetic results complicate the diagnosis of SLC35A2-CDG, our data indicate that the combination of these three elements can support the pathogenicity of mutations in SLC35A2.
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Affiliation(s)
- Mari-Anne Vals
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
- Children's Clinic, Tartu University Hospital, Tartu, Estonia
| | - Angel Ashikov
- Donders Institute for Brain, Cognition, and Behavior, Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Pilvi Ilves
- Radiology Clinic, Tartu University Hospital, Tartu, Estonia
- Department of Radiology, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Dagmar Loorits
- Radiology Clinic, Tartu University Hospital, Tartu, Estonia
- Department of Radiology, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Qiang Zeng
- GlycoScience Group, National Institute for Bioprocessing Research & Training, Dublin, Ireland
| | - Rita Barone
- Child Neurology and Psychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
- Department of Clinical and Experimental Medicine, Referral Centre for Inherited Metabolic Diseases, University of Catania, Catania, Italy
| | - Karin Huijben
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jolanta Sykut-Cegielska
- Department of Inborn Errors of Metabolism and Paediatrics, Institute of Mother and Child, Warsaw, Poland
| | - Luísa Diogo
- Child Developmental Center, Hospital Pediátrico, Center for Inherited Metabolic Diseases, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Abdallah F Elias
- Department of Medical Genetics, Shodair Children's Hospital, Helena, Montana
| | - Robert S Greenwood
- Department of Neurology, University of North Carolina School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Stephanie Grunewald
- Metabolic Unit, Great Ormond Street Hospital and Institute of Child Health, University College London, NHS Trust, London, UK
| | - Peter M van Hasselt
- Division Pediatrics, Metabolic Diseases, Wilhelmina Children's Hospital (Part of UMC Utrecht), Utrecht, The Netherlands
| | - Jiddeke M van de Kamp
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands
| | - Grazia Mancini
- Department of Clinical Genetics, Erasmus MC University Medical Centre, Rotterdam, The Netherlands
| | - Agnieszka Okninska
- Clinic of Children and Adolescent Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Sander Pajusalu
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Pauline M Rudd
- GlycoScience Group, National Institute for Bioprocessing Research & Training, Dublin, Ireland
| | - Cecilie F Rustad
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Ramona Salvarinova
- Division of Biochemical Diseases, Department of Pediatrics, British Columbia Children's Hospital, UBC BC Children's Hospital Research Institute, Vancouver, Canada
| | - Bert B A de Vries
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Nicole I Wolf
- Department of Child Neurology and Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
| | - Bobby G Ng
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Hudson H Freeze
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Dirk J Lefeber
- Donders Institute for Brain, Cognition, and Behavior, Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Katrin Õunap
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
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8
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014. MASS SPECTROMETRY REVIEWS 2018; 37:353-491. [PMID: 29687922 DOI: 10.1002/mas.21530] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 11/29/2016] [Indexed: 06/08/2023]
Abstract
This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.
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Affiliation(s)
- David J Harvey
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FZ, United Kingdom
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9
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Ng BG, Freeze HH. Perspectives on Glycosylation and Its Congenital Disorders. Trends Genet 2018; 34:466-476. [PMID: 29606283 DOI: 10.1016/j.tig.2018.03.002] [Citation(s) in RCA: 164] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/04/2018] [Accepted: 03/05/2018] [Indexed: 12/12/2022]
Abstract
Congenital disorders of glycosylation (CDG) are a rapidly expanding group of metabolic disorders that result from abnormal protein or lipid glycosylation. They are often difficult to clinically diagnose because they broadly affect many organs and functions and lack clinical uniformity. However, recent technological advances in next-generation sequencing have revealed a treasure trove of new genetic disorders, expanded the knowledge of known disorders, and showed a critical role in infectious diseases. More comprehensive genetic tools specifically tailored for mammalian cell-based models have revealed a critical role for glycosylation in pathogen-host interactions, while also identifying new CDG susceptibility genes. We highlight recent advancements that have resulted in a better understanding of human glycosylation disorders, perspectives for potential future therapies, and mysteries for which we continue to seek new insights and solutions.
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Affiliation(s)
- Bobby G Ng
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Hudson H Freeze
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
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10
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Dörre K, Olczak M, Wada Y, Sosicka P, Grüneberg M, Reunert J, Kurlemann G, Fiedler B, Biskup S, Hörtnagel K, Rust S, Marquardt T. A new case of UDP-galactose transporter deficiency (SLC35A2-CDG): molecular basis, clinical phenotype, and therapeutic approach. J Inherit Metab Dis 2015; 38:931-40. [PMID: 25778940 DOI: 10.1007/s10545-015-9828-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 02/10/2015] [Accepted: 02/13/2015] [Indexed: 10/23/2022]
Abstract
Congenital disorders of glycosylation (CDG) are a group of hereditary metabolic diseases characterized by abnormal glycosylation of proteins and lipids. Often, multisystem disorders with central nervous system involvement and a large variety of clinical symptoms occur. The main characteristics are developmental delay, seizures, and ataxia. In this paper we report the clinical and biochemical characteristics of a 5-year-old girl with a defective galactosylation of N-glycans, resulting in developmental delay, muscular hypotonia, epileptic seizures, inverted nipples, and visual impairment. Next generation sequencing revealed a de novo mutation (c.797G > T, p.G266V) in the X-chromosomal gene SLC35A2 (solute carrier family 35, UDP-galactose transporter, member A2; MIM 300896). While this mutation was found heterozygous, random X-inactivation of the normal allele will lead to loss of normal SLC35A2 activity in respective cells. The functional relevance of the mutation was demonstrated by complementation of UGT-deficient MDCK-RCA(r) and CHO-Lec8 cells by normal UGT-expression construct but not by the mutant version. The effect of dietary galactose supplementation on glycosylation was investigated, showing a nearly complete normalization of transferrin glycosylation.
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Affiliation(s)
- K Dörre
- Universitätsklinikum Münster, Klinik für Kinder-und Jugendmedizin, Albert-Schweitzer-Campus 1, 48149, Muenster, Germany
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11
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Maszczak-Seneczko D, Sosicka P, Kaczmarek B, Majkowski M, Luzarowski M, Olczak T, Olczak M. UDP-galactose (SLC35A2) and UDP-N-acetylglucosamine (SLC35A3) Transporters Form Glycosylation-related Complexes with Mannoside Acetylglucosaminyltransferases (Mgats). J Biol Chem 2015; 290:15475-15486. [PMID: 25944901 DOI: 10.1074/jbc.m115.636670] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Indexed: 01/18/2023] Open
Abstract
UDP-galactose transporter (UGT; SLC35A2) and UDP-N-acetylglucosamine transporter (NGT; SLC35A3) form heterologous complexes in the Golgi membrane. NGT occurs in close proximity to mannosyl (α-1,6-)-glycoprotein β-1,6-N-acetylglucosaminyltransferase (Mgat5). In this study we analyzed whether NGT and both splice variants of UGT (UGT1 and UGT2) are able to interact with four different mannoside acetylglucosaminyltransferases (Mgat1, Mgat2, Mgat4B, and Mgat5). Using an in situ proximity ligation assay, we found that all examined glycosyltransferases are in the vicinity of these UDP-sugar transporters both at the endogenous level and upon overexpression. This observation was confirmed via the FLIM-FRET approach for both NGT and UGT1 complexes with Mgats. This study reports for the first time close proximity between endogenous nucleotide sugar transporters and glycosyltransferases. We also observed that among all analyzed Mgats, only Mgat4B occurs in close proximity to UGT2, whereas the other three Mgats are more distant from UGT2, and it was only possible to visualize their vicinity using proximity ligation assay. This strongly suggests that the distance between these protein pairs is longer than 10 nm but at the same time shorter than 40 nm. This study adds to the understanding of glycosylation, one of the most important post-translational modifications, which affects the majority of macromolecules. Our research shows that complex formation between nucleotide sugar transporters and glycosyltransferases might be a more common phenomenon than previously thought.
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Affiliation(s)
- Dorota Maszczak-Seneczko
- Laboratories of Biochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Paulina Sosicka
- Laboratories of Biochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Beata Kaczmarek
- Laboratories of Biochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Michał Majkowski
- Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Marcin Luzarowski
- Laboratories of Biochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Teresa Olczak
- Laboratories of Biochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Mariusz Olczak
- Laboratories of Biochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland.
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Sosicka P, Jakimowicz P, Olczak T, Olczak M. Short N-terminal region of UDP-galactose transporter (SLC35A2) is crucial for galactosylation of N-glycans. Biochem Biophys Res Commun 2014; 454:486-92. [PMID: 25451267 DOI: 10.1016/j.bbrc.2014.10.098] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 10/17/2014] [Indexed: 11/28/2022]
Abstract
UDP-galactose transporter (UGT) and UDP-N-acetylglucosamine transporter (NGT) form heterologous complexes in the Golgi apparatus (GA) membrane. We aimed to identify UGT region responsible for galactosylation of N-glycans. Chimeric proteins composed of human UGT and either NGT or CMP-sialic acid transporter (CST) localized to the GA, and all but UGT/CST chimera corrected galactosylation defect in UGT-deficient cell lines, although at different efficiency. Importantly, short N-terminal region composed of 35 N-terminal amino-acid residues of UGT was crucial for galactosylation of N-glycans. The remaining molecule must be derived from NGT not CST, confirming that the role played by UGT and NGT is coupled.
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Affiliation(s)
- Paulina Sosicka
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wroclaw, 14A F. Joliot-Curie St., 50-383 Wroclaw, Poland
| | - Piotr Jakimowicz
- Laboratory of Biotechnology, Faculty of Biotechnology, University of Wroclaw, 14A F. Joliot-Curie St., 50-383 Wroclaw, Poland
| | - Teresa Olczak
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wroclaw, 14A F. Joliot-Curie St., 50-383 Wroclaw, Poland
| | - Mariusz Olczak
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wroclaw, 14A F. Joliot-Curie St., 50-383 Wroclaw, Poland.
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13
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Baulch JE, Aypar U, Waters KM, Yang AJ, Morgan WF. Genetic and epigenetic changes in chromosomally stable and unstable progeny of irradiated cells. PLoS One 2014; 9:e107722. [PMID: 25251398 PMCID: PMC4175465 DOI: 10.1371/journal.pone.0107722] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 08/15/2014] [Indexed: 01/28/2023] Open
Abstract
Radiation induced genomic instability is a well-studied phenomenon, the underlying mechanisms of which are poorly understood. Persistent oxidative stress, mitochondrial dysfunction, elevated cytokine levels and epigenetic changes are among the mechanisms invoked in the perpetuation of the phenotype. To determine whether epigenetic aberrations affect genomic instability we measured DNA methylation, mRNA and microRNA (miR) levels in well characterized chromosomally stable and unstable clonally expanded single cell survivors of irradiation. While no changes in DNA methylation were observed for the gene promoters evaluated, increased LINE-1 methylation was observed for two unstable clones (LS12 and CS9) and decreased Alu element methylation was observed for the other two unstable clones (115 and Fe5.0–8). These relationships also manifested for mRNA and miR expression. mRNA identified for the LS12 and CS9 clones were most similar to each other (261 mRNA), while the 115 and Fe5.0–8 clones were more similar to each other, and surprisingly also similar to the two stable clones, 114 and 118 (286 mRNA among these four clones). Pathway analysis showed enrichment for pathways involved in mitochondrial function and cellular redox, themes routinely invoked in genomic instability. The commonalities between the two subgroups of clones were also observed for miR. The number of miR for which anti-correlated mRNA were identified suggests that these miR exert functional effects in each clone. The results demonstrate significant genetic and epigenetic changes in unstable cells, but similar changes are almost as equally common in chromosomally stable cells. Possible conclusions might be that the chromosomally stable clones have some other form of instability, or that some of the observed changes represent a sort of radiation signature and that other changes are related to genomic instability. Irrespective, these findings again suggest that a spectrum of changes both drive genomic instability and permit unstable cells to persist and proliferate.
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Affiliation(s)
- Janet E. Baulch
- Department of Radiation Oncology, University of California Irvine, Irvine, California, United States of America
- * E-mail:
| | - Umut Aypar
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Katrina M. Waters
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Austin J. Yang
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - William F. Morgan
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
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Hadley B, Maggioni A, Ashikov A, Day CJ, Haselhorst T, Tiralongo J. Structure and function of nucleotide sugar transporters: Current progress. Comput Struct Biotechnol J 2014; 10:23-32. [PMID: 25210595 PMCID: PMC4151994 DOI: 10.1016/j.csbj.2014.05.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The proteomes of eukaryotes, bacteria and archaea are highly diverse due, in part, to the complex post-translational modification of protein glycosylation. The diversity of glycosylation in eukaryotes is reliant on nucleotide sugar transporters to translocate specific nucleotide sugars that are synthesised in the cytosol and nucleus, into the endoplasmic reticulum and Golgi apparatus where glycosylation reactions occur. Thirty years of research utilising multidisciplinary approaches has contributed to our current understanding of NST function and structure. In this review, the structure and function, with reference to various disease states, of several NSTs including the UDP-galactose, UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine, GDP-fucose, UDP-N-acetylglucosamine/UDP-glucose/GDP-mannose and CMP-sialic acid transporters will be described. Little is known regarding the exact structure of NSTs due to difficulties associated with crystallising membrane proteins. To date, no three-dimensional structure of any NST has been elucidated. What is known is based on computer predictions, mutagenesis experiments, epitope-tagging studies, in-vitro assays and phylogenetic analysis. In this regard the best-characterised NST to date is the CMP-sialic acid transporter (CST). Therefore in this review we will provide the current state-of-play with respect to the structure–function relationship of the (CST). In particular we have summarised work performed by a number groups detailing the affect of various mutations on CST transport activity, efficiency, and substrate specificity.
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Affiliation(s)
- Barbara Hadley
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Andrea Maggioni
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Angel Ashikov
- Institut für Zelluläre Chemie, Zentrum Biochemie, Medizinische Hochschule Hannover, Carl-Neuberg Strasse 1, 30625 Hannover, Germany ; Laboratory of Genetic, Endocrine and Metabolic Diseases, Department of Neurology, Radboud University Medical Center, Geert Grooteplein Zuid 10 (route 830), Nijmegen, The Netherlands
| | - Christopher J Day
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Thomas Haselhorst
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Joe Tiralongo
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
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Maszczak-Seneczko D, Sosicka P, Olczak T, Jakimowicz P, Majkowski M, Olczak M. UDP-N-acetylglucosamine transporter (SLC35A3) regulates biosynthesis of highly branched N-glycans and keratan sulfate. J Biol Chem 2013; 288:21850-60. [PMID: 23766508 DOI: 10.1074/jbc.m113.460543] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SLC35A3 is considered the main UDP-N-acetylglucosamine transporter (NGT) in mammals. Detailed analysis of NGT is restricted because mammalian mutant cells defective in this activity have not been isolated. Therefore, using the siRNA approach, we developed and characterized several NGT-deficient mammalian cell lines. CHO, CHO-Lec8, and HeLa cells deficient in NGT activity displayed a decrease in the amount of highly branched tri- and tetraantennary N-glycans, whereas monoantennary and diantennary ones remained unchanged or even were accumulated. Silencing the expression of NGT in Madin-Darby canine kidney II cells resulted in a dramatic decrease in the keratan sulfate content, whereas no changes in biosynthesis of heparan sulfate were observed. We also demonstrated for the first time close proximity between NGT and mannosyl (α-1,6-)-glycoprotein β-1,6-N-acetylglucosaminyltransferase (Mgat5) in the Golgi membrane. We conclude that NGT may be important for the biosynthesis of highly branched, multiantennary complex N-glycans and keratan sulfate. We hypothesize that NGT may specifically supply β-1,3-N-acetylglucosaminyl-transferase 7 (β3GnT7), Mgat5, and possibly mannosyl (α-1,3-)-glycoprotein β-1,4-N-acetylglucosaminyltransferase (Mgat4) with UDP-GlcNAc.
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Affiliation(s)
- Dorota Maszczak-Seneczko
- Laboratory of Biochemistry, Faculty of Biotechnology, University of Wrocław, 2 Tamka Street, 50-137 Wrocław, Poland
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