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Altassan R, Allers MM, De Graef D, Shah R, de Vries M, Larson A, Glamuzina E, Morava E. Defining the phenotype of PGAP3-congenital disorder of glycosylation; a review of 65 cases. Mol Genet Metab 2023; 140:107688. [PMID: 37647829 PMCID: PMC10872732 DOI: 10.1016/j.ymgme.2023.107688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023]
Abstract
Biallelic pathogenic variants in PGAP3 cause a rare glycosylphosphatidyl-inositol biogenesis disorder, PGAP3-CDG. This multisystem condition presents with a predominantly neurological phenotype, including developmental delay, intellectual disability, seizures, and hyperphosphatemia. Here, we summarized the phenotype of sixty-five individuals including six unreported individuals from our CDG natural history study with a confirmed PGAP3-CDG diagnosis. Common additional features found in this disorder included brain malformations, behavioral abnormalities, cleft palate, and characteristic facial features. This report aims to review the genetic and metabolic findings and characterize the disease's phenotype while highlighting the necessary clinical approach to improve the management of this rare CDG.
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Affiliation(s)
- Ruqaiah Altassan
- Department of Medical Genomics, Centre for Genomics Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States; College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Michael M Allers
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States
| | - Diederik De Graef
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States
| | - Rameen Shah
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Maaike de Vries
- Department of Pediatrics, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Austin Larson
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Emma Glamuzina
- Adult and Paediatric National Metabolic Service, Auckland City Hospital, Auckland, New Zealand
| | - Eva Morava
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States; Department of Medical Genetics, University of Pecs Medical School, Pecs, Hungary.
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2
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Lukeš J, Speijer D, Zíková A, Alfonzo JD, Hashimi H, Field MC. Trypanosomes as a magnifying glass for cell and molecular biology. Trends Parasitol 2023; 39:902-912. [PMID: 37679284 DOI: 10.1016/j.pt.2023.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 09/09/2023]
Abstract
The African trypanosome, Trypanosoma brucei, has developed into a flexible and robust experimental model for molecular and cellular parasitology, allowing us to better combat these and related parasites that cause worldwide suffering. Diminishing case numbers, due to efficient public health efforts, and recent development of new drug treatments have reduced the need for continued study of T. brucei in a disease context. However, we argue that this pathogen has been instrumental in revolutionary discoveries that have widely informed molecular and cellular biology and justifies continuing research as an experimental model. Ongoing work continues to contribute towards greater understanding of both diversified and conserved biological features. We discuss multiple examples where trypanosomes pushed the boundaries of cell biology and hope to inspire researchers to continue exploring these remarkable protists as tools for magnifying the inner workings of cells.
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Affiliation(s)
- Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic.
| | - Dave Speijer
- Medical Biochemistry, University of Amsterdam, AMC, Amsterdam, The Netherlands
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Juan D Alfonzo
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Hassan Hashimi
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Mark C Field
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; School of Life Sciences, University of Dundee, Dundee, UK
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3
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Borges AR, Link F, Engstler M, Jones NG. The Glycosylphosphatidylinositol Anchor: A Linchpin for Cell Surface Versatility of Trypanosomatids. Front Cell Dev Biol 2021; 9:720536. [PMID: 34790656 PMCID: PMC8591177 DOI: 10.3389/fcell.2021.720536] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/06/2021] [Indexed: 11/20/2022] Open
Abstract
The use of glycosylphosphatidylinositol (GPI) to anchor proteins to the cell surface is widespread among eukaryotes. The GPI-anchor is covalently attached to the C-terminus of a protein and mediates the protein’s attachment to the outer leaflet of the lipid bilayer. GPI-anchored proteins have a wide range of functions, including acting as receptors, transporters, and adhesion molecules. In unicellular eukaryotic parasites, abundantly expressed GPI-anchored proteins are major virulence factors, which support infection and survival within distinct host environments. While, for example, the variant surface glycoprotein (VSG) is the major component of the cell surface of the bloodstream form of African trypanosomes, procyclin is the most abundant protein of the procyclic form which is found in the invertebrate host, the tsetse fly vector. Trypanosoma cruzi, on the other hand, expresses a variety of GPI-anchored molecules on their cell surface, such as mucins, that interact with their hosts. The latter is also true for Leishmania, which use GPI anchors to display, amongst others, lipophosphoglycans on their surface. Clearly, GPI-anchoring is a common feature in trypanosomatids and the fact that it has been maintained throughout eukaryote evolution indicates its adaptive value. Here, we explore and discuss GPI anchors as universal evolutionary building blocks that support the great variety of surface molecules of trypanosomatids.
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Affiliation(s)
- Alyssa R Borges
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Fabian Link
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Markus Engstler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Nicola G Jones
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
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4
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Kabiri M, Steverding D. Trypanosoma brucei transferrin receptor: Functional replacement of the GPI anchor with a transmembrane domain. Mol Biochem Parasitol 2021; 242:111361. [PMID: 33450336 DOI: 10.1016/j.molbiopara.2021.111361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 10/22/2022]
Abstract
The transferrin receptor of Trypanosoma brucei (TbTfR) is a heterodimer of a glycosylphosphatidylinositol (GPI)-anchored ESAG6 subunit and an ESAG7 subunit. To investigate whether the GPI-anchor is essential for the function of the TbTfR, an ESAG6 with a transmembrane domain instead of a GPI-anchor (ESAG6tmd) was inducibly expressed in bloodstream form trypanosomes. It is shown that the ESAG6tmd is able to dimerise with ESAG7 to form a TbTfR that can bind transferrin. Fractionation experiments clearly demonstrated that the transmembrane-anchored TbTfR is exclusively associated with the membrane fraction. No difference in the uptake of transferrin was observed between trypanosomes inducibly expressing a transmembrane-anchored TbTfR and trypanosomes inducibly expressing a GPI-anchored TbTfR. Differences in glycosylation pattern of ESAG6tmd and native ESAG6 may indicate different intracellular trafficking of transmembrane- and GPI-anchored TbTfRs. The findings suggest that the GPI-anchor is not essential for the function of the TbTfR in bloodstream forms of T. brucei.
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Affiliation(s)
- Mostafa Kabiri
- Abteilung Parasitologie, Hygiene-Institut der Ruprecht-Karls Universität, Heidelberg, Germany; Sanofi Aventis Deutschland, Translational in Vivo Models, Sanofi Research and Development, Frankfurt, Germany
| | - Dietmar Steverding
- Abteilung Parasitologie, Hygiene-Institut der Ruprecht-Karls Universität, Heidelberg, Germany; Bob Champion Research and Education Centre, Norwich Medical School, University of East Anglia, Norwich, United Kingdom.
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5
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Carmody LC, Blau H, Danis D, Zhang XA, Gourdine JP, Vasilevsky N, Krawitz P, Thompson MD, Robinson PN. Significantly different clinical phenotypes associated with mutations in synthesis and transamidase+remodeling glycosylphosphatidylinositol (GPI)-anchor biosynthesis genes. Orphanet J Rare Dis 2020; 15:40. [PMID: 32019583 PMCID: PMC7001271 DOI: 10.1186/s13023-020-1313-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 01/21/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Defects in the glycosylphosphatidylinositol (GPI) biosynthesis pathway can result in a group of congenital disorders of glycosylation known as the inherited GPI deficiencies (IGDs). To date, defects in 22 of the 29 genes in the GPI biosynthesis pathway have been identified in IGDs. The early phase of the biosynthetic pathway assembles the GPI anchor (Synthesis stage) and the late phase transfers the GPI anchor to a nascent peptide in the endoplasmic reticulum (ER) (Transamidase stage), stabilizes the anchor in the ER membrane using fatty acid remodeling and then traffics the GPI-anchored protein to the cell surface (Remodeling stage). RESULTS We addressed the hypothesis that disease-associated variants in either the Synthesis stage or Transamidase+Remodeling-stage GPI pathway genes have distinct phenotypic spectra. We reviewed clinical data from 58 publications describing 152 individual patients and encoded the phenotypic information using the Human Phenotype Ontology (HPO). We showed statistically significant differences between the Synthesis and Transamidase+Remodeling Groups in the frequencies of phenotypes in the musculoskeletal system, cleft palate, nose phenotypes, and cognitive disability. Finally, we hypothesized that phenotypic defects in the IGDs are likely to be at least partially related to defective GPI anchoring of their target proteins. Twenty-two of one hundred forty-two proteins that receive a GPI anchor are associated with one or more Mendelian diseases and 12 show some phenotypic overlap with the IGDs, represented by 34 HPO terms. Interestingly, GPC3 and GPC6, members of the glypican family of heparan sulfate proteoglycans bound to the plasma membrane through a covalent GPI linkage, are associated with 25 of these phenotypic abnormalities. CONCLUSIONS IGDs associated with Synthesis and Transamidase+Remodeling stages of the GPI biosynthesis pathway have significantly different phenotypic spectra. GPC2 and GPC6 genes may represent a GPI target of general disruption to the GPI biosynthesis pathway that contributes to the phenotypes of some IGDs.
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Affiliation(s)
- Leigh C Carmody
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA
| | - Hannah Blau
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA
| | - Daniel Danis
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA
| | - Xingman A Zhang
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA
| | | | | | - Peter Krawitz
- Institute of Genomic Statistics and Bioinformatics, University of Bonn, Bonn, Germany
| | - Miles D Thompson
- Department of Pediatrics, UCSD School of Medicine, La Jolla, CA, 92093, USA
| | - Peter N Robinson
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA. .,Institute for Systems Genomics, University of Connecticut, Farmington, CT, USA.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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7
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Abstract
Organelles have been studied traditionally as single units, but a novel concept is now emerging: each organelle has distinct functional zones that regulate specific functions. The Golgi apparatus seems to have various zones, including zones for: glycosylphosphatidylinositol-anchored proteins; proteoglycan, mucin and lipid glycosylation; transport of cholesterol and ceramides; protein degradation (Golgi membrane-associated degradation); and signalling for apoptosis. The capacity for these specific functions and the size of the corresponding zones appear to be tightly regulated by the Golgi stress response to accommodate cellular demands. For instance, the proteoglycan and mucin zones seem to be separately augmented during the differentiation of chondrocytes and goblet cells, respectively. The mammalian Golgi stress response consists of several response pathways. The TFE3 pathway regulates the general function of the Golgi, such as structural maintenance, N-glycosylation and vesicular transport, whereas the proteoglycan pathway increases the expression of glycosylation enzymes for proteoglycans. The CREB3 and HSP47 pathways regulate pro- and anti-apoptotic functions, respectively. These observations indicate that the Golgi is a dynamic organelle, the capacity of which is upregulated according to cellular needs.
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Affiliation(s)
- Kanae Sasaki
- Department of Molecular Biochemistry, Graduate School of Life Science, University of Hyogo, Japan
| | - Hiderou Yoshida
- Department of Molecular Biochemistry, Graduate School of Life Science, University of Hyogo, Japan
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8
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Leyton L, Díaz J, Martínez S, Palacios E, Pérez LA, Pérez RD. Thy-1/CD90 a Bidirectional and Lateral Signaling Scaffold. Front Cell Dev Biol 2019; 7:132. [PMID: 31428610 PMCID: PMC6689999 DOI: 10.3389/fcell.2019.00132] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/04/2019] [Indexed: 01/18/2023] Open
Abstract
Thy-1/CD90 is a glycoprotein attached to the outer face of the plasma membrane with various functions, which depend on the context of specific physiological or pathological conditions. Many of these reported functions for Thy-1/CD90 arose from studies by our group, which identified the first ligand/receptor for Thy-1/CD90 as an integrin. This finding initiated studies directed toward unveiling the molecular mechanisms that operate downstream of Thy-1/CD90 activation, and its possible interaction with proteins in the membrane plane to regulate their function. The association of Thy-1/CD90 with a number of cell surface molecules allows the formation of extra/intracellular multiprotein complexes composed of various ligands and receptors, extracellular matrix proteins, intracellular signaling proteins, and the cytoskeleton. The complexes sense changes that occur inside and outside the cells, with Thy-1/CD90 at the core of this extracellular molecular platform. Molecular platforms are scaffold-containing microdomains where key proteins associate to prominently influence cellular processes and behavior. Each component, by itself, is less effective, but when together with various scaffold proteins to form a platform, the components become more specific and efficient to convey the messages. This review article discusses the experimental evidence that supports the role of Thy-1/CD90 as a membrane-associated platform (ThyMAP).
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Affiliation(s)
- Lisette Leyton
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Exercise, Metabolism and Cancer Studies (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Jorge Díaz
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Exercise, Metabolism and Cancer Studies (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Samuel Martínez
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Exercise, Metabolism and Cancer Studies (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Esteban Palacios
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Exercise, Metabolism and Cancer Studies (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Laboratorio de Microbiología Celular, Facultad de Ciencias de la Salud, Universidad Central de Chile, Santiago, Chile
| | - Leonardo A Pérez
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Exercise, Metabolism and Cancer Studies (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Ramón D Pérez
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Exercise, Metabolism and Cancer Studies (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
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9
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Burgstaller S, Bischof H, Gensch T, Stryeck S, Gottschalk B, Ramadani-Muja J, Eroglu E, Rost R, Balfanz S, Baumann A, Waldeck-Weiermair M, Hay JC, Madl T, Graier WF, Malli R. pH-Lemon, a Fluorescent Protein-Based pH Reporter for Acidic Compartments. ACS Sens 2019; 4:883-891. [PMID: 30864782 PMCID: PMC6488996 DOI: 10.1021/acssensors.8b01599] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Distinct subcellular pH levels, especially in lysosomes and endosomes, are essential for the degradation, modification, sorting, accumulation, and secretion of macromolecules. Here, we engineered a novel genetically encoded pH probe by fusing the pH-stable cyan fluorescent protein (FP) variant, mTurquoise2, to the highly pH-sensitive enhanced yellow fluorescent protein, EYFP. This approach yielded a ratiometric biosensor-referred to as pH-Lemon-optimized for live imaging of distinct pH conditions within acidic cellular compartments. Protonation of pH-Lemon under acidic conditions significantly decreases the yellow fluorescence while the cyan fluorescence increases due to reduced Förster resonance energy transfer (FRET) efficiency. Because of its freely reversible and ratiometric responses, pH-Lemon represents a fluorescent biosensor for pH dynamics. pH-Lemon also shows a sizable pH-dependent fluorescence lifetime change that can be used in fluorescence lifetime imaging microscopy as an alternative observation method for the study of pH in acidic cellular compartments. Fusion of pH-Lemon to the protein microtubule-associated protein 1A/1B-light chain 3B (LC3B), a specific marker of autophagic membranes, resulted in its targeting within autolysosomes of HeLa cells. Moreover, fusion of pH-Lemon to a glycophosphatidylinositol (GPI) anchor allowed us to monitor the entire luminal space of the secretory pathway and the exoplasmic leaflet of the plasma membrane. Utilizing this new pH probe, we revealed neutral and acidic vesicles and substructures inside cells, highlighting compartments of distinct pH throughout the endomembrane system. These data demonstrate, that this novel pH sensor, pH-Lemon, is very suitable for the study of local pH dynamics of subcellular microstructures in living cells.
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Affiliation(s)
- Sandra Burgstaller
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Helmut Bischof
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Thomas Gensch
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Sarah Stryeck
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Benjamin Gottschalk
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Jeta Ramadani-Muja
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Emrah Eroglu
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Rene Rost
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Sabine Balfanz
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Arnd Baumann
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Markus Waldeck-Weiermair
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Jesse C. Hay
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
- Division of Biological Sciences and Center for Structural and Functional Neuroscience, The University of Montana, 32 Campus Drive, HS410, Missoula 59812-4824, Montana United States
| | - Tobias Madl
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
- BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Wolfgang F. Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
- BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
- BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
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10
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Pan HP, Wang N, Tachikawa H, Nakanishi H, Gao XD. β-1,6-glucan synthesis-associated genes are required for proper spore wall formation in Saccharomyces cerevisiae. Yeast 2017; 34:431-446. [PMID: 28732129 DOI: 10.1002/yea.3244] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/16/2017] [Accepted: 07/16/2017] [Indexed: 01/30/2023] Open
Abstract
The yeast spore wall is an excellent model to study the assembly of an extracellular macromolecule structure. In the present study, mutants defective in β-1,6-glucan synthesis, including kre1∆, kre6∆, kre9∆ and big1∆, were sporulated to analyse the effect of β-1,6-glucan defects on the spore wall. Except for kre6∆, these mutant spores were sensitive to treatment with ether, suggesting that the mutations perturb the integrity of the spore wall. Morphologically, the mutant spores were indistinguishable from wild-type spores. They lacked significant sporulation defects partly because the chitosan layer, which covers the glucan layer, compensated for the damage. The proof for this model was obtained from the effect of the additional deletion of CHS3 that resulted in the absence of the chitosan layer. Among the double mutants, the most severe spore wall deficiency was observed in big1∆ spores. The majority of the big1∆chs3∆ mutants failed to form visible spores at a higher temperature. Given that the big1∆ mutation caused a failure to attach a GPI-anchored reporter, Cwp2-GFP, to the spore wall, β-1,6-glucan is involved in tethering of GPI-anchored proteins in the spore wall as well as in the vegetative cell wall. Thus, β-1,6-glucan is required for proper organization of the spore wall. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Hua-Ping Pan
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Hiroyuki Tachikawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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11
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Walliser I, Göbel TW. Generation of glycosylphosphatidylinositol linked chicken IL-17 to generate specific monoclonal antibodies applicable for intracellular cytokine staining. Dev Comp Immunol 2017; 73:27-35. [PMID: 28284737 DOI: 10.1016/j.dci.2017.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/06/2017] [Accepted: 03/06/2017] [Indexed: 06/06/2023]
Abstract
Interleukin 17 (IL-17) cytokines play a crucial role in host defense and inflammatory diseases. Of the six mammalian IL-17 members five are described in the chicken (gg) genome. A novel method that attached cytokines to the surface of cells via a GPI linker was established to generate two chicken IL-17A and one chicken IL-17F specific mab. Recombinant gg IL-17A and gg IL-17F that showed dimerization in Western blot were used to verify the antibodies specificity. The mab could detect gg IL-17 by intracellular cytokine staining as demonstrated on cells expressing recombinant IL-17. Furthermore IL-17A and lower amounts of IL-17F were detectable in CD4 positive T cells of stimulated splenocytes. In conclusion, we have generated novel tools to analyze chicken IL-17 in more detail and demonstrated that the surface expression of cytokines is a reliable method to generate specific mab applicable for intracellular cytokine staining.
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Affiliation(s)
- Isabelle Walliser
- Institute for Animal Physiology, Department of Veterinary Sciences, University of Munich, Veterinärstrasse 13, 80539 Munich, Germany
| | - Thomas W Göbel
- Institute for Animal Physiology, Department of Veterinary Sciences, University of Munich, Veterinärstrasse 13, 80539 Munich, Germany.
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12
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Xue H, Veit C, Abas L, Tryfona T, Maresch D, Ricardi MM, Estevez JM, Strasser R, Seifert GJ. Arabidopsis thaliana FLA4 functions as a glycan-stabilized soluble factor via its carboxy-proximal Fasciclin 1 domain. Plant J 2017; 91:613-630. [PMID: 28482115 PMCID: PMC5575511 DOI: 10.1111/tpj.13591] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/18/2017] [Accepted: 04/28/2017] [Indexed: 05/12/2023]
Abstract
Fasciclin-like arabinogalactan proteins (FLAs) are involved in numerous important functions in plants but the relevance of their complex structure to physiological function and cellular fate is unresolved. Using a fully functional fluorescent version of Arabidopsis thaliana FLA4 we show that this protein is localized at the plasma membrane as well as in endosomes and soluble in the apoplast. FLA4 is likely to be GPI-anchored, is highly N-glycosylated and carries two O-glycan epitopes previously associated with arabinogalactan proteins. The activity of FLA4 was resistant against deletion of the amino-proximal fasciclin 1 domain and was unaffected by removal of the GPI-modification signal, a highly conserved N-glycan or the deletion of predicted O-glycosylation sites. Nonetheless these structural changes dramatically decreased endoplasmic reticulum (ER)-exit and plasma membrane localization of FLA4, with N-glycosylation acting at the level of ER-exit and O-glycosylation influencing post-secretory fate. We show that FLA4 acts predominantly by molecular interactions involving its carboxy-proximal fasciclin 1 domain and that its amino-proximal fasciclin 1 domain is required for stabilization of plasma membrane localization. FLA4 functions as a soluble glycoprotein via its carboxy-proximal Fas1 domain and its normal cellular trafficking depends on N- and O-glycosylation.
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Affiliation(s)
- Hui Xue
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life ScienceBOKU ViennaMuthgasse 11A‐1190ViennaAustria
| | - Christiane Veit
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life ScienceBOKU ViennaMuthgasse 11A‐1190ViennaAustria
| | - Lindy Abas
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life ScienceBOKU ViennaMuthgasse 11A‐1190ViennaAustria
| | - Theodora Tryfona
- Department of BiochemistryUniversity of CambridgeCambridgeCB2 1QWUK
| | - Daniel Maresch
- Department of ChemistryUniversity of Natural Resources and Life ScienceBOKU ViennaMuthgasse 11A‐1190ViennaAustria
| | - Martiniano M. Ricardi
- Biología Molecular y Neurociencias–Consejo Nacional de Investigaciones Científicas y Técnicas(IFIByNE‐CONICET)Instituto de FisiologíaFacultad de Ciencias Exactas y NaturalesUniversidad de Buenos AiresBuenos AiresC1428EGAArgentina
| | - José Manuel Estevez
- Biología Molecular y Neurociencias–Consejo Nacional de Investigaciones Científicas y Técnicas(IFIByNE‐CONICET)Instituto de FisiologíaFacultad de Ciencias Exactas y NaturalesUniversidad de Buenos AiresBuenos AiresC1428EGAArgentina
- Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos AiresBuenos Aires CPC1405BWEArgentina
| | - Richard Strasser
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life ScienceBOKU ViennaMuthgasse 11A‐1190ViennaAustria
| | - Georg J. Seifert
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life ScienceBOKU ViennaMuthgasse 11A‐1190ViennaAustria
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13
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Kimoto T, Miura D. Detection of In Vivo Mutation in the Pig-a Gene of Mouse Bone Marrow Erythroids. Methods Mol Biol 2017; 1641:161-72. [PMID: 28748463 DOI: 10.1007/978-1-4939-7172-5_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Detection of in vivo mutation is important for evaluating the health risks associated with chemicals. The Pig-a in vivo gene mutation assay has been developed over the last decade for this purpose. Most approaches for the assay, however, measure cells with a Pig-a mutant phenotype in erythrocytes from the peripheral blood, with the mutations causing the phenotype being difficult to determine directly. This chapter describes a procedure for detecting mutations in the Pig-a gene of phenotypically mutant mouse bone marrow erythroids, the precursors of peripheral blood erythrocytes. The strategy for molecular analysis of Pig-a gene mutation includes enrichment of GPI-anchor deficient cells with a cell sorter followed by a cloning and sequencing of Pig-a cDNAs.
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14
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Staudt E, Ramasamy P, Plattner H, Simon M. Differential subcellular distribution of four phospholipase C isoforms and secretion of GPI-PLC activity. Biochim Biophys Acta 2016; 1858:3157-3168. [PMID: 27693913 DOI: 10.1016/j.bbamem.2016.09.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/04/2016] [Accepted: 09/27/2016] [Indexed: 12/11/2022]
Abstract
Phospholipase C (PLC) is an important enzyme of signal transduction pathways by generation of second messengers from membrane lipids. PLCs are also indicated to cleave glycosylphosphatidylinositol (GPI)-anchors of surface proteins thus releasing these into the environment. However, it remains unknown whether this enzymatic activity on the surface is due to distinct PLC isoforms in higher eukaryotes. Ciliates have, in contrast to other unicellular eukaryotes, multiple PLC isoforms as mammals do. Thus, Paramecium represents a perfect model to study subcellular distribution and potential surface activity of PLC isoforms. We have identified distinct subcellular localizations of four PLC isoforms indicating functional specialization. The association with different calcium release channels (CRCs) argues for distinct subcellular functions. They may serve as PI-PLCs in microdomains for local second messenger responses rather than free floating IP3. In addition, all isoforms can be found on the cell surface and they are found together with GPI-cleaved surface proteins in salt/ethanol washes of cells. We can moreover show them in medium supernatants of living cells where they have access to GPI-anchored surface proteins. Among the isoforms we cannot assign GPI-PLC activity to specific PLC isoforms; rather each PLC is potentially responsible for the release of GPI-anchored proteins from the surface.
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Affiliation(s)
- Emanuel Staudt
- Saarland University, Molecular Cell Dynamics, Centre for Human and Molecular Biology, Campus A2 4, 66123 Saarbrücken, Germany; University of Kaiserslautern, Department of Biology, Erwin-Schrödinger Straße, Building Nr. 14, 67663 Kaiserslautern, Germany
| | - Pathmanaban Ramasamy
- Saarland University, Molecular Cell Dynamics, Centre for Human and Molecular Biology, Campus A2 4, 66123 Saarbrücken, Germany
| | - Helmut Plattner
- University of Konstanz, Senior Research Group for Cell Biology and Ultrastructure Research, Department of Biology, 78457 Konstanz, Germany
| | - Martin Simon
- Saarland University, Molecular Cell Dynamics, Centre for Human and Molecular Biology, Campus A2 4, 66123 Saarbrücken, Germany.
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15
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Itoh Y. Membrane-type matrix metalloproteinases: Their functions and regulations. Matrix Biol 2015; 44-46:207-23. [PMID: 25794647 DOI: 10.1016/j.matbio.2015.03.004] [Citation(s) in RCA: 270] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 03/11/2015] [Accepted: 03/11/2015] [Indexed: 12/22/2022]
Abstract
Membrane-type matrix metalloproteinases (MT-MMPs) form a subgroup of the matrix metalloproteinase (MMP) family, and there are 6 MT-MMPs in humans. MT-MMPs are further sub-classified into type I transmembrane-type (MT1, -MT2-, MT3- and MT5-MMPs) and glycosylphosphatidylinositol (GPI)-anchored type (MT4- and MT6-MMPs). In either case MT-MMPs are tethered to the plasma membrane, and this cell surface expression provides those enzymes with unique functionalities affecting various cellular behaviours. Among the 6 MT-MMPs, MT1-MMP is the most investigated enzyme and many of its roles and regulations have been revealed to date, but the potential roles and regulatory mechanisms of other MT-MMPs are gradually getting clearer as well. Further investigations of MT-MMPs are likely to reveal novel pathophysiological mechanisms and potential therapeutic strategies for different diseases in the future.
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Affiliation(s)
- Yoshifumi Itoh
- Kennedy Institute of Rheumatology, University of Oxford, Roosevelt Drive, Headington, Oxford OX3 7FY, UK.
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16
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Izquierdo L, Acosta-Serrano A, Mehlert A, Ferguson MA. Identification of a glycosylphosphatidylinositol anchor-modifying β1-3 galactosyltransferase in Trypanosoma brucei. Glycobiology 2014; 25:438-47. [PMID: 25467966 PMCID: PMC4339879 DOI: 10.1093/glycob/cwu131] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Trypanosoma brucei is the causative agent of human African sleeping sickness and the cattle disease nagana. Trypanosoma brucei is dependent on glycoproteins for its survival and infectivity throughout its life cycle. Here we report the functional characterization of TbGT3, a glycosyltransferase expressed in the bloodstream and procyclic form of the parasite. Bloodstream and procyclic form TbGT3 conditional null mutants were created and both exhibited normal growth under permissive and nonpermissive conditions. Under nonpermissive conditions, the normal glycosylation of the major glycoprotein of bloodstream form T. brucei, the variant surface glycoprotein and the absence of major alterations in lectin binding to other glycoproteins suggested that the major function of TbGT3 occurs in the procyclic form of the parasite. Consistent with this, the major surface glycoprotein of the procyclic form, procyclin, exhibited a marked reduction in molecular weight due to changes in glycosylphosphatidylinositol (GPI) anchor side chains. Structural analysis of the mutant procyclin GPI anchors indicated that TbGT3 encodes a UDP-Gal: β-GlcNAc-GPI β1-3 Gal transferase. Despite the alterations in GPI anchor side chains, TbGT3 conditional null mutants remained infectious to tsetse flies under nonpermissive conditions.
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Affiliation(s)
- Luis Izquierdo
- Division of Biological Chemistry and Drug Discovery, The College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK Barcelona Centre for International Health Research, CRESIB, Hospital Clínic-Universitat de Barcelona, Barcelona 08036, Spain
| | - Alvaro Acosta-Serrano
- Department of Parasitology Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Angela Mehlert
- Division of Biological Chemistry and Drug Discovery, The College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Michael Aj Ferguson
- Division of Biological Chemistry and Drug Discovery, The College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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17
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Belet S, Fieremans N, Yuan X, Van Esch H, Verbeeck J, Ye Z, Cheng L, Brodsky BR, Hu H, Kalscheuer VM, Brodsky RA, Froyen G. Early frameshift mutation in PIGA identified in a large XLID family without neonatal lethality. Hum Mutat 2014; 35:350-5. [PMID: 24357517 DOI: 10.1002/humu.22498] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 12/12/2013] [Indexed: 11/09/2022]
Abstract
The phosphatidylinositol glycan class A (PIGA) protein is a member of the glycosylphosphatidylinositol anchor pathway. Germline mutations in PIGA located at Xp22.2 are thought to be lethal in males. However, a nonsense mutation in the last coding exon was recently described in two brothers with multiple congenital anomalies-hypotonia-seizures syndrome 2 (MCAHS2) who survived through birth likely because of the hypomorphic nature of the truncated protein, but died in their first weeks of life. Here, we report on a frameshift mutation early in the PIGA cDNA (c.76dupT; p.Y26Lfs*3) that cosegregates with the disease in a large family diagnosed with a severe syndromic form of X-linked intellectual disability. Unexpectedly, CD59 surface expression suggested the production of a shorter PIGA protein with residual functionality. We provide evidence that the second methionine at position 37 may be used for the translation of a 36 amino acids shorter PIGA. Complementation assays confirmed that this shorter PIGA cDNA was able to partially rescue the surface expression of CD59 in a PIGA-null cell line. Taken together, our data strongly suggest that the early frameshift mutation in PIGA produces a truncated hypomorph, which is sufficient to rescue the lethality in males but not the MCAHS2-like phenotype.
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Affiliation(s)
- Stefanie Belet
- Human Genome Laboratory, VIB Center for the Biology of Disease, Leuven, Belgium; Human Genome Laboratory, Department of Human Genetics, KU Leuven, Leuven, Belgium
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18
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Nakanishi M, Karasudani M, Shiraishi T, Hashida K, Hino M, Ferguson MAJ, Nomoto H. TbGT8 is a bifunctional glycosyltransferase that elaborates N-linked glycans on a protein phosphatase AcP115 and a GPI-anchor modifying glycan in Trypanosoma brucei. Parasitol Int 2014; 63:513-8. [PMID: 24508870 PMCID: PMC4003530 DOI: 10.1016/j.parint.2014.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/25/2013] [Accepted: 01/20/2014] [Indexed: 11/01/2022]
Abstract
The procyclic form of Trypanosoma brucei expresses procyclin surface glycoproteins with unusual glycosylphosphatidylinositol-anchor side chain structures that contain branched N-acetyllactosamine and lacto-N-biose units. The glycosyltransferase TbGT8 is involved in the synthesis of the branched side chain through its UDP-GlcNAc: βGal β1-3N-acetylglucosaminyltransferase activity. Here, we explored the role of TbGT8 in the mammalian bloodstream form of the parasite with a tetracycline-inducible conditional null T. brucei mutant for TbGT8. Under non-permissive conditions, the mutant showed significantly reduced binding to tomato lectin, which recognizes poly-N-acetyllactosamine-containing glycans. Lectin pull-down assays revealed differences between the wild type and TbGT8 null-mutant T. brucei, notably the absence of a broad protein band with an approximate molecular weight of 110 kDa in the mutant lysate. Proteomic analysis revealed that the band contained several glycoproteins, including the acidic ecto-protein phosphatase AcP115, a stage-specific glycoprotein in the bloodstream form of T. brucei. Western blotting with an anti-AcP115 antibody revealed that AcP115 was approximately 10kDa smaller in the mutant. Enzymatic de-N-glycosylation demonstrated that the underlying protein cores were the same, suggesting that the 10-kDa difference was due to differences in N-linked glycans. Immunofluorescence microscopy revealed the colocalization of hemagglutinin epitope-tagged TbGT8 and the Golgi-associated protein GRASP. These data suggest that TbGT8 is involved in the construction of complex poly-N-acetyllactosamine-containing type N-linked and GPI-linked glycans in the Golgi of the bloodstream and procyclic parasite forms, respectively.
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Affiliation(s)
- Masayuki Nakanishi
- Laboratory of Biochemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime 790-8578, Japan.
| | - Moe Karasudani
- Laboratory of Biochemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime 790-8578, Japan
| | - Takahiro Shiraishi
- Laboratory of Biochemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime 790-8578, Japan
| | - Kazunori Hashida
- Laboratory of Biochemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime 790-8578, Japan
| | - Mami Hino
- Laboratory of Biochemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime 790-8578, Japan
| | - Michael A J Ferguson
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Hiroshi Nomoto
- Laboratory of Biochemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime 790-8578, Japan
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19
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Guizzunti G, Zurzolo C. The fate of PrP GPI-anchor signal peptide is modulated by P238S pathogenic mutation. Traffic 2013; 15:78-93. [PMID: 24112521 DOI: 10.1111/tra.12126] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 09/24/2013] [Accepted: 10/01/2013] [Indexed: 12/30/2022]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins are localized to the plasma membrane via a C-terminally linked GPI anchor. The GPI anchor is added concomitantly to the cleavage of the carboxy-terminal GPI-anchor signal sequence, thereby causing the release of a C-terminal hydrophobic peptide, whose fate has not yet been investigated. Here we followed the fate of the GPI-attachment signal of the prion protein (PrP), a protein implicated in various types of transmissible neurodegenerative spongiform encephalopathies (TSE). The PrP GPI-anchor signal sequence shows a remarkable and unusual degree of conservation across the species and contains two point mutations (M232R/T and P238S) that are responsible for genetic forms of prion disorders. We show that the PrP GPI-anchor signal peptide (SP), but not the one from an unrelated GPI-anchored protein (folate receptor), undergoes degradation via the proteasome. Moreover, the P238S point mutation partially protects the PrP GPI-anchor SP from degradation. Our data provide the first attempt to address the fate of a GPI-anchor SP and identify a role for the P238S mutation, suggesting the possibility that the PrP GPI-anchor SP could play a role in neurodegenerative prion diseases.
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Affiliation(s)
- Gianni Guizzunti
- Institut Pasteur, Unité de Trafic Membranaire et Pathogenèse, 25-28 rue du Docteur Roux, 75015, Paris, France
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20
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Lynch DV, Dunn TM. An introduction to plant sphingolipids and a review of recent advances in understanding their metabolism and function. New Phytol 2004; 161:677-702. [PMID: 33873728 DOI: 10.1111/j.1469-8137.2004.00992.x] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Sphingolipids are ubiquitous constituents of eukaryotic cells, and have been intensively investigated in mammals and yeast for decades. Aspects of sphingolipid biochemistry in plants have been explored only recently. To date, progress has been made in determining the structure and occurrence of sphingolipids in plant tissues; in characterizing the enzymatic steps involved in production and turnover of sphingolipids (and, in some cases, the genes encoding the relevant enzymes); and in identifying a variety of biological functions for sphingolipids in plants. Given that these efforts are far from complete and much remains to be learned, this review represents a status report on the burgeoning field of plant sphingolipid biochemistry. Contents Summary 677 I. Introduction 678 II. Plant sphingolipid structure 678 III. Sphingolipid metabolism in plants 683 IV. Sphingolipid functions in plants 693 V. Conclusions 696 Acknowledgements 696 References 696.
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Affiliation(s)
- Daniel V Lynch
- Department of Biology, Williams College, Williamstown, MA 01267, USA
| | - Teresa M Dunn
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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