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Li S, Tang Q, Jiang Y, Chen X. Inherited glycosylphosphatidylinositol deficiency: a review from molecular and clinical perspectives. Acta Biochim Biophys Sin (Shanghai) 2024; 56:1234-1243. [PMID: 39081219 DOI: 10.3724/abbs.2024128] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024] Open
Abstract
Glycosylphosphatidylinositol (GPI) is a highly conserved post-translational modification in eukaryotes, which is essential for anchoring various proteins to the cell surface. Dysfunction of GPI biogenesis leads to human diseases, such as inherited GPI deficiency (IGD) caused by germline mutations in GPI-related genes. With accumulating reports on individuals with IGD, there has been increasing interest and studies on disease mechanism, diagnosis, and therapy. This review outlines the biosynthetic pathway of GPI-anchored proteins (GPI-APs) and summarizes clinical IGD cases from a molecular perspective. We also review current diagnostic and therapeutic approaches for IGD. Finally, we discuss future research directions to facilitate the understanding and treatment of GPI-related disorders.
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Affiliation(s)
- Shan Li
- Children's Medical Center, Peking University First Hospital, Beijing 100034, China
| | - Qi Tang
- College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
| | - Yuwu Jiang
- Children's Medical Center, Peking University First Hospital, Beijing 100034, China
| | - Xing Chen
- College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
- Synthetic and Functional Biomolecules Center, Peking University, Beijing 100871, China
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing 100871, China
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2
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Komath SS. To each its own: Mechanisms of cross-talk between GPI biosynthesis and cAMP-PKA signaling in Candida albicans versus Saccharomyces cerevisiae. J Biol Chem 2024; 300:107444. [PMID: 38838772 PMCID: PMC11294708 DOI: 10.1016/j.jbc.2024.107444] [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: 03/19/2024] [Revised: 05/24/2024] [Accepted: 05/29/2024] [Indexed: 06/07/2024] Open
Abstract
Candida albicans is an opportunistic fungal pathogen that can switch between yeast and hyphal morphologies depending on the environmental cues it receives. The switch to hyphal form is crucial for the establishment of invasive infections. The hyphal form is also characterized by the cell surface expression of hyphae-specific proteins, many of which are GPI-anchored and important determinants of its virulence. The coordination between hyphal morphogenesis and the expression of GPI-anchored proteins is made possible by an interesting cross-talk between GPI biosynthesis and the cAMP-PKA signaling cascade in the fungus; a parallel interaction is not found in its human host. On the other hand, in the nonpathogenic yeast, Saccharomyces cerevisiae, GPI biosynthesis is shut down when filamentation is activated and vice versa. This too is achieved by a cross-talk between GPI biosynthesis and cAMP-PKA signaling. How are diametrically opposite effects obtained from the cross-talk between two reasonably well-conserved pathways present ubiquitously across eukarya? This Review attempts to provide a model to explain these differences. In order to do so, it first provides an overview of the two pathways for the interested reader, highlighting the similarities and differences that are observed in C. albicans versus the well-studied S. cerevisiae model, before going on to explain how the different mechanisms of regulation are effected. While commonalities enable the development of generalized theories, it is hoped that a more nuanced approach, that takes into consideration species-specific differences, will enable organism-specific understanding of these processes and contribute to the development of targeted therapies.
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Li D. Structure and Function of the Glycosylphosphatidylinositol Transamidase, a Transmembrane Complex Catalyzing GPI Anchoring of Proteins. Subcell Biochem 2024; 104:425-458. [PMID: 38963495 DOI: 10.1007/978-3-031-58843-3_16] [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] [Indexed: 07/05/2024]
Abstract
Glycosylphosphatidylinositol (GPI) anchoring of proteins is a ubiquitous posttranslational modification in eukaryotic cells. GPI-anchored proteins (GPI-APs) play critical roles in enzymatic, signaling, regulatory, and adhesion processes. Over 20 enzymes are involved in GPI synthesis, attachment to client proteins, and remodeling after attachment. The GPI transamidase (GPI-T), a large complex located in the endoplasmic reticulum membrane, catalyzes the attachment step by replacing a C-terminal signal peptide of proproteins with GPI. In the last three decades, extensive research has been conducted on the mechanism of the transamidation reaction, the components of the GPI-T complex, the role of each subunit, and the substrate specificity. Two recent studies have reported the three-dimensional architecture of GPI-T, which represent the first structures of the pathway. The structures provide detailed mechanisms for assembly that rationalizes previous biochemical results and subunit-dependent stability data. While the structural data confirm the catalytic role of PIGK, which likely uses a caspase-like mechanism to cleave the proproteins, they suggest that unlike previously proposed, GPAA1 is not a catalytic subunit. The structures also reveal a shared cavity for GPI binding. Somewhat unexpectedly, PIGT, a single-pass membrane protein, plays a crucial role in GPI recognition. Consistent with the assembly mechanisms and the active site architecture, most of the disease mutations occur near the active site or the subunit interfaces. Finally, the catalytic dyad is located ~22 Å away from the membrane interface of the GPI-binding site, and this architecture may confer substrate specificity through topological matching between the substrates and the elongated active site. The research conducted thus far sheds light on the intricate processes involved in GPI anchoring and paves the way for further mechanistic studies of GPI-T.
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Affiliation(s)
- Dianfan Li
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), Shanghai, China.
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4
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Xu Y, Li T, Zhou Z, Hong J, Chao Y, Zhu Z, Zhang Y, Qu Q, Li D. Structures of liganded glycosylphosphatidylinositol transamidase illuminate GPI-AP biogenesis. Nat Commun 2023; 14:5520. [PMID: 37684232 PMCID: PMC10491789 DOI: 10.1038/s41467-023-41281-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/25/2023] [Indexed: 09/10/2023] Open
Abstract
Many eukaryotic receptors and enzymes rely on glycosylphosphatidylinositol (GPI) anchors for membrane localization and function. The transmembrane complex GPI-T recognizes diverse proproteins at a signal peptide region that lacks consensus sequence and replaces it with GPI via a transamidation reaction. How GPI-T maintains broad specificity while preventing unintentional cleavage is unclear. Here, substrates- and products-bound human GPI-T structures identify subsite features that enable broad proprotein specificity, inform catalytic mechanism, and reveal a multilevel safeguard mechanism against its promiscuity. In the absence of proproteins, the catalytic site is invaded by a locally stabilized loop. Activation requires energetically unfavorable rearrangements that transform the autoinhibitory loop into crucial catalytic cleft elements. Enzyme-proprotein binding in the transmembrane and luminal domains respectively powers the conformational rearrangement and induces a competent cleft. GPI-T thus integrates various weak specificity regions to form strong selectivity and prevent accidental activation. These findings provide important mechanistic insights into GPI-anchored protein biogenesis.
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Affiliation(s)
- Yidan Xu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), University of CAS, Shanghai, China
| | - Tingting Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), University of CAS, Shanghai, China
| | - Zixuan Zhou
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, Shanghai, China
| | - Jingjing Hong
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), University of CAS, Shanghai, China
| | - Yulin Chao
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, Shanghai, China
| | - Zhini Zhu
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, Shanghai, China
| | - Ying Zhang
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, Shanghai, China
| | - Qianhui Qu
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, Shanghai, China.
| | - Dianfan Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), University of CAS, Shanghai, China.
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5
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Ishida M, Maki Y, Ninomiya A, Takada Y, Campeau P, Kinoshita T, Murakami Y. Ethanolamine-phosphate on the second mannose is a preferential bridge for some GPI-anchored proteins. EMBO Rep 2022; 23:e54352. [PMID: 35603428 PMCID: PMC9253782 DOI: 10.15252/embr.202154352] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 04/13/2022] [Accepted: 04/25/2022] [Indexed: 09/10/2023] Open
Abstract
Glycosylphosphatidylinositols (GPIs) are glycolipids that anchor many proteins (GPI-APs) on the cell surface. The core glycan of GPI precursor has three mannoses, which in mammals, are all modified by ethanolamine-phosphate (EthN-P). It is postulated that EthN-P on the third mannose (EthN-P-Man3) is the bridge between GPI and the protein and the second (EthN-P-Man2) is removed after GPI-protein attachment. However, EthN-P-Man2 may not be always transient, as mutations of PIGG, the enzyme that transfers EthN-P to Man2, result in inherited GPI deficiencies (IGDs), characterized by neuronal dysfunctions. Here, we show that EthN-P on Man2 is the preferential bridge in some GPI-APs, among them, the Ect-5'-nucleotidase and Netrin G2. We find that CD59, a GPI-AP, is attached via EthN-P-Man2 both in PIGB-knockout cells, in which GPI lacks Man3, and with a small fraction in wild-type cells. Our findings modify the current view of GPI anchoring and provide a mechanistic basis for IGDs caused by PIGG mutations.
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Affiliation(s)
- Mizuki Ishida
- Yabumoto Department of Intractable Disease ResearchResearch Institute for Microbial DiseasesOsaka UniversitySuitaJapan
| | - Yuta Maki
- Department of ChemistryOsaka UniversityToyonakaJapan
- Project Research Center for Fundamental SciencesGraduate School of ScienceOsaka UniversityToyonakaJapan
| | - Akinori Ninomiya
- Central Instrumentation LaboratoryResearch Institute for Microbial DiseasesOsaka UniversitySuitaJapan
| | - Yoko Takada
- WPI Immunology Frontier Research CenterOsaka UniversitySuitaJapan
| | - Philippe Campeau
- Department of PediatricsCHU Sainte‐Justine and University of MontrealMontrealQCCanada
| | - Taroh Kinoshita
- Yabumoto Department of Intractable Disease ResearchResearch Institute for Microbial DiseasesOsaka UniversitySuitaJapan
- WPI Immunology Frontier Research CenterOsaka UniversitySuitaJapan
- Center for Infectious Disease Education and ResearchOsaka UniversitySuitaJapan
| | - Yoshiko Murakami
- Yabumoto Department of Intractable Disease ResearchResearch Institute for Microbial DiseasesOsaka UniversitySuitaJapan
- WPI Immunology Frontier Research CenterOsaka UniversitySuitaJapan
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6
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Xu Y, Jia G, Li T, Zhou Z, Luo Y, Chao Y, Bao J, Su Z, Qu Q, Li D. Molecular insights into biogenesis of glycosylphosphatidylinositol anchor proteins. Nat Commun 2022; 13:2617. [PMID: 35551457 PMCID: PMC9098846 DOI: 10.1038/s41467-022-30250-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/22/2022] [Indexed: 02/08/2023] Open
Abstract
Eukaryotic cells are coated with an abundance of glycosylphosphatidylinositol anchor proteins (GPI-APs) that play crucial roles in fertilization, neurogenesis, and immunity. The removal of a hydrophobic signal peptide and covalent attachment of GPI at the new carboxyl terminus are catalyzed by an endoplasmic reticulum membrane GPI transamidase complex (GPI-T) conserved among all eukaryotes. Here, we report the cryo-electron microscopy (cryo-EM) structure of the human GPI-T at a global 2.53-Å resolution, revealing an equimolar heteropentameric assembly. Structure-based mutagenesis suggests a legumain-like mechanism for the recognition and cleavage of proprotein substrates, and an endogenous GPI in the structure defines a composite cavity for the lipid substrate. This elongated active site, stemming from the membrane and spanning an additional ~22-Å space toward the catalytic dyad, is structurally suited for both substrates which feature an amphipathic pattern that matches this geometry. Our work presents an important step towards the mechanistic understanding of GPI-AP biosynthesis. GPI-T catalyzes the committed step in GPI anchor protein biogenesis. Here, Xu et al. report the cryo-EM structure of the human GPI-T, revealing critical elements within an elongated, shared active site which is topologically arranged for substrate specificity.
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Affiliation(s)
- Yidan Xu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China
| | - Guowen Jia
- State Key Laboratory of Biotherapy and Cancer Center, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, 610044, Chengdu, China
| | - Tingting Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China
| | - Zixuan Zhou
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, 200032, Shanghai, China
| | - Yitian Luo
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, 201210, Shanghai, China
| | - Yulin Chao
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, 200032, Shanghai, China
| | - Juan Bao
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China
| | - Zhaoming Su
- State Key Laboratory of Biotherapy and Cancer Center, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, 610044, Chengdu, China.
| | - Qianhui Qu
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, 200032, Shanghai, China.
| | - Dianfan Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China.
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7
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Hirata T, Kobayashi A, Furuse T, Yamada I, Tamura M, Tomita H, Tokoro Y, Ninomiya A, Fujihara Y, Ikawa M, Maeda Y, Murakami Y, Kizuka Y, Kinoshita T. Loss of the N-acetylgalactosamine side chain of the GPI-anchor impairs bone formation and brain functions and accelerates the prion disease pathology. J Biol Chem 2022; 298:101720. [PMID: 35151686 PMCID: PMC8913354 DOI: 10.1016/j.jbc.2022.101720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 01/28/2022] [Accepted: 01/29/2022] [Indexed: 02/07/2023] Open
Abstract
Glycosylphosphatidylinositol (GPI) is a posttranslational glycolipid modification of proteins that anchors proteins in lipid rafts on the cell surface. Although some GPI-anchored proteins (GPI-APs), including the prion protein PrPC, have a glycan side chain composed of N-acetylgalactosamine (GalNAc)−galactose−sialic acid on the core structure of GPI glycolipid, in vivo functions of this GPI-GalNAc side chain are largely unresolved. Here, we investigated the physiological and pathological roles of the GPI-GalNAc side chain in vivo by knocking out its initiation enzyme, PGAP4, in mice. We show that Pgap4 mRNA is highly expressed in the brain, particularly in neurons, and mass spectrometry analysis confirmed the loss of the GalNAc side chain in PrPC GPI in PGAP4-KO mouse brains. Furthermore, PGAP4-KO mice exhibited various phenotypes, including an elevated blood alkaline phosphatase level, impaired bone formation, decreased locomotor activity, and impaired memory, despite normal expression levels and lipid raft association of various GPI-APs. Thus, we conclude that the GPI-GalNAc side chain is required for in vivo functions of GPI-APs in mammals, especially in bone and the brain. Moreover, PGAP4-KO mice were more vulnerable to prion diseases and died earlier after intracerebral inoculation of the pathogenic prion strains than wildtype mice, highlighting the protective roles of the GalNAc side chain against prion diseases.
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Affiliation(s)
- Tetsuya Hirata
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan
| | - Atsushi Kobayashi
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Tamio Furuse
- Technology and Development Team for Mouse Phenotype Analysis, RIKEN BioResource Research Center, Tsukuba, Ibaraki, Japan
| | - Ikuko Yamada
- Technology and Development Team for Mouse Phenotype Analysis, RIKEN BioResource Research Center, Tsukuba, Ibaraki, Japan
| | - Masaru Tamura
- Technology and Development Team for Mouse Phenotype Analysis, RIKEN BioResource Research Center, Tsukuba, Ibaraki, Japan
| | - Hiroyuki Tomita
- Department of Tumor Pathology, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Yuko Tokoro
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan
| | - Akinori Ninomiya
- Core Instrumentation Facility, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Yoshitaka Fujihara
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Masahito Ikawa
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Yusuke Maeda
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Yoshiko Murakami
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Yasuhiko Kizuka
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan.
| | - Taroh Kinoshita
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan.
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8
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Hirata T. Biology of Glycosylphosphatidylinositol (GPI)-anchor Side Chains and Free GPI. TRENDS GLYCOSCI GLYC 2021. [DOI: 10.4052/tigg.2041.1j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Tetsuya Hirata
- Institute for Glyco-core Research (iGCORE), Gifu University
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9
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Hirata T. Biology of Glycosylphosphatidylinositol (GPI)-anchor Side Chains and Free GPI. TRENDS GLYCOSCI GLYC 2021. [DOI: 10.4052/tigg.2041.1e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Tetsuya Hirata
- Institute for Glyco-core Research (iGCORE), Gifu University
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10
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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] [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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11
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A knockout cell library of GPI biosynthetic genes for functional studies of GPI-anchored proteins. Commun Biol 2021; 4:777. [PMID: 34162996 PMCID: PMC8222316 DOI: 10.1038/s42003-021-02337-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/19/2021] [Indexed: 11/08/2022] Open
Abstract
Over 100 kinds of proteins are expressed as glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) on the cell surface in mammalian cells. GPI-APs possess unique properties in terms of their intracellular trafficking and association with lipid rafts. Although it is clear that GPI-APs play critical roles in various biological phenomena, it is poorly understood how the GPI moiety contributes to these mechanisms. More than 30 genes are involved in the correct biosynthesis of GPI-APs. We here constructed a cell library in which 32 genes involved in GPI biosynthesis were knocked out in human embryonic kidney 293 cells. Using the cell library, the surface expression and sensitivity to phosphatidylinositol-specific phospholipase C of GPI-APs were analyzed. Furthermore, we identified structural motifs of GPIs that are recognized by a GPI-binding toxin, aerolysin. The cell-based GPI-knockout library could be applied not only to basic researches, but also to applications and methodologies related to GPI-APs.
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12
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Beihammer G, Maresch D, Altmann F, Strasser R. Glycosylphosphatidylinositol-Anchor Synthesis in Plants: A Glycobiology Perspective. FRONTIERS IN PLANT SCIENCE 2020; 11:611188. [PMID: 33312189 PMCID: PMC7704450 DOI: 10.3389/fpls.2020.611188] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 10/30/2020] [Indexed: 05/02/2023]
Abstract
More than 200 diverse secretory proteins from Arabidopsis thaliana carry a glycosylphosphatidylinositol (GPI) lipid anchor covalently attached to their carboxyl-terminus. The GPI-anchor contains a lipid-linked glycan backbone that is preassembled in the endoplasmic reticulum (ER) of plants and subsequently transferred to distinct proteins, which provides them with specific features. The GPI-anchored proteins exit the ER and are transported through the Golgi apparatus to the plasma membrane. In the Golgi, the glycan moiety can be further modified by the specific attachment of sugar residues. While these biosynthetic steps are already quite well understood in mammals and yeast, comparatively little is known in plants. In this perspective, we discuss the current knowledge about the biosynthesis of the GPI-anchor glycan moiety in the light of recent findings for mammalian GPI-anchor glycan modifications.
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Affiliation(s)
- Gernot Beihammer
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Daniel Maresch
- Division of Biochemistry, Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Friedrich Altmann
- Division of Biochemistry, Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
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13
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Müller GA. Membrane insertion and intercellular transfer of glycosylphosphatidylinositol-anchored proteins: potential therapeutic applications. Arch Physiol Biochem 2020; 126:139-156. [PMID: 30445857 DOI: 10.1080/13813455.2018.1498904] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Anchorage of a subset of cell surface proteins in eukaryotic cells is mediated by a glycosylphosphatidylinositol (GPI) moiety covalently attached to the carboxy-terminus of the protein moiety. Experimental evidence for the potential of GPI-anchored proteins (GPI-AP) of being released from cells into the extracellular environment has been accumulating, which involves either the loss or retention of the GPI anchor. Release of GPI-AP from donor cells may occur spontaneously or in response to endogenous or environmental signals. The experimental evidence for direct insertion of exogenous GPI-AP equipped with the complete anchor structure into the outer plasma membrane bilayer leaflets of acceptor cells is reviewed as well as the potential underlying molecular mechanisms. Furthermore, promiscuous transfer of certain GPI-AP between plasma membranes of different cells in vivo under certain (patho)physiological conditions has been reported. Engineering of target cell surfaces using chimeric GPI-AP with complete GPI anchor may be useful for therapeutic applications.
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Affiliation(s)
- Günter A Müller
- Helmholtz Diabetes Center (HDC) at the Helmholtz Center München, Institute for Diabetes and Obesity, Oberschleissheim, Germany
- Department Biology I, Genetics, Ludwig-Maximilians-University München, Planegg-Martinsried, Germany
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14
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Zhou Y, Fu X, Zheng Z, Ren Y, Zheng Z, Zhang B, Yuan M, Duan J, Li M, Hong T, Lu G, Zhou D. Identification of gene co-expression modules and hub genes associated with the invasiveness of pituitary adenoma. Endocrine 2020; 68:377-389. [PMID: 32342269 DOI: 10.1007/s12020-020-02316-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/13/2020] [Indexed: 10/24/2022]
Abstract
In pituitary adenoma (PA), invasiveness is the main cause of recurrence and poor prognosis. Thus, identifying specific biomarkers for diagnosis and effective treatment of invasive PAs is of great clinical significance. In this study, from the Gene Expression Omnibus database, we obtained and combined several microarrays of PA by the "sva" R package. Weighted gene co-expression network analysis was performed to construct a scale-free topology model and analyze the relationships between the modules and clinical traits. Our analysis results indicated that three key modules (dark turquoise, saddle brown, and steel blue) were associated with the invasiveness of PA. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis and Gene Ontology analysis were performed for the functional annotation of the key modules. In addition, the hub genes in the three modules were identified and screened by differential expression analysis between normal samples and PA samples. Three upregulated differentially expressed genes (DGAT2, PIGZ, and DHRS2) were identified. The Fisher's exact test and receiver operating characteristic curve were used to validate the capability of these genes to distinguish invasive traits, and transcription factor interaction networks were used to further explore the underlying mechanisms of the three genes. Moreover, a lower expression level of DGAT2 in invasive PA tissue than in noninvasive PA tissue was validated by quantitative reverse transcription-polymerase chain reaction. In general, this study contributes to potential molecular biomarkers of invasive PAs and provides a broader perspective for diagnosis and new therapeutic targets for the invasive PAs.
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Affiliation(s)
- Yuancheng Zhou
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China
- The First Clinical Medical College of Nanchang University, Nanchang, Jiangxi, PR China
| | - Xiaorui Fu
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China
- Medical Department, Queen Mary College , Nanchang University, Nanchang, Jiangxi, China
| | - Zhicheng Zheng
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China
- The Fourth Clinical Medical College of Nanchang University, Nanchang, Jiangxi, PR China
| | - Yu Ren
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China
- The First Clinical Medical College of Nanchang University, Nanchang, Jiangxi, PR China
| | - Zijian Zheng
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China
- The First Clinical Medical College of Nanchang University, Nanchang, Jiangxi, PR China
| | - Bohan Zhang
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China
- The First Clinical Medical College of Nanchang University, Nanchang, Jiangxi, PR China
| | - Min Yuan
- Shanggao County People's Hospital, Yichun, Jiangxi, PR China
| | - Jian Duan
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China
| | - Meihua Li
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China
| | - Tao Hong
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China
| | - Guohui Lu
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China.
| | - Dongwei Zhou
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, PR China.
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15
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Kobayashi A, Hirata T, Nishikaze T, Ninomiya A, Maki Y, Takada Y, Kitamoto T, Kinoshita T. α2,3 linkage of sialic acid to a GPI anchor and an unpredicted GPI attachment site in human prion protein. J Biol Chem 2020; 295:7789-7798. [PMID: 32321762 DOI: 10.1074/jbc.ra120.013444] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 04/18/2020] [Indexed: 12/20/2022] Open
Abstract
Prion diseases are transmissible, lethal neurodegenerative disorders caused by accumulation of the aggregated scrapie form of the prion protein (PrPSc) after conversion of the cellular prion protein (PrPC). The glycosylphosphatidylinositol (GPI) anchor of PrPC is involved in prion disease pathogenesis, and especially sialic acid in a GPI side chain reportedly affects PrPC conversion. Thus, it is important to define the location and structure of the GPI anchor in human PrPC Moreover, the sialic acid linkage type in the GPI side chain has not been determined for any GPI-anchored protein. Here we report GPI glycan structures of human PrPC isolated from human brains and from brains of a knock-in mouse model in which the mouse prion protein (Prnp) gene was replaced with the human PRNP gene. LC-electrospray ionization-MS analysis of human PrPC from both biological sources indicated that Gly229 is the ω site in PrPC to which GPI is attached. Gly229 in human PrPC does not correspond to Ser231, the previously reported ω site of Syrian hamster PrPC We found that ∼41% and 28% of GPI anchors in human PrPCs from human and knock-in mouse brains, respectively, have N-acetylneuraminic acid in the side chain. Using a sialic acid linkage-specific alkylamidation method to discriminate α2,3 linkage from α2,6 linkage, we found that N-acetylneuraminic acid in PrPC's GPI side chain is linked to galactose through an α2,3 linkage. In summary, we report the GPI glycan structure of human PrPC, including the ω-site amino acid for GPI attachment and the sialic acid linkage type.
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Affiliation(s)
- Atsushi Kobayashi
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Tetsuya Hirata
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.,WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Takashi Nishikaze
- Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation, Kyoto, Japan
| | - Akinori Ninomiya
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Yuta Maki
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - Yoko Takada
- WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Tetsuyuki Kitamoto
- Department of Neurological Science, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, Japan
| | - Taroh Kinoshita
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan .,WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
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16
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Yamamoto-Hino M, Kawaguchi K, Ono M, Furukawa K, Goto S. Lamin is essential for nuclear localization of the GPI synthesis enzyme PIG-B and GPI-anchored protein production in Drosophila. J Cell Sci 2020; 133:jcs.238527. [PMID: 32051283 PMCID: PMC7104860 DOI: 10.1242/jcs.238527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 01/28/2020] [Indexed: 01/13/2023] Open
Abstract
Membrane lipid biosynthesis is a complex process that occurs in various intracellular compartments. In Drosophila, phosphatidylinositol glycan-B (PIG-B), which catalyzes addition of the third mannose in glycosylphosphatidylinositol (GPI), localizes to the nuclear envelope (NE). Although this NE localization is essential for Drosophila development, the underlying molecular mechanism remains unknown. To elucidate this mechanism, we identified PIG-B-interacting proteins by performing immunoprecipitation followed by proteomic analysis. We then examined which of these proteins are required for the NE localization of PIG-B. Knockdown of Lamin Dm0, a B-type lamin, led to mislocalization of PIG-B from the NE to the endoplasmic reticulum. Lamin Dm0 associated with PIG-B at the inner nuclear membrane, a process that required the tail domain of Lamin Dm0. Furthermore, GPI moieties were distributed abnormally in the Lamin Dm0 mutant. These data indicate that Lamin Dm0 is involved in the NE localization of PIG-B and is required for proper GPI-anchor modification of proteins. Highlighted Article: Lamin plays a role in post-translational modification of plasma membrane proteins by tethering the GPI modification enzyme PIG-B to the inner nuclear membrane.
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Affiliation(s)
- Miki Yamamoto-Hino
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
| | - Kohei Kawaguchi
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
| | - Masaya Ono
- Department of Clinical Proteomics, National Cancer Center Hospital, Chu-o-ku, Tokyo 104-0045, Japan
| | - Kazuhiro Furukawa
- Department of Chemistry, Faculty of Science, Niigata University, Niigata 950-2181, Japan
| | - Satoshi Goto
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
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17
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Abstract
At least 150 human proteins are glycosylphosphatidylinositol-anchored proteins (GPI-APs). The protein moiety of GPI-APs lacking transmembrane domains is anchored to the plasma membrane with GPI covalently attached to the C-terminus. The GPI consists of the conserved core glycan, phosphatidylinositol and glycan side chains. The entire GPI-AP is anchored to the outer leaflet of the lipid bilayer by insertion of fatty chains of phosphatidylinositol. Because of GPI-dependent membrane anchoring, GPI-APs have some unique characteristics. The most prominent feature of GPI-APs is their association with membrane microdomains or membrane rafts. In the polarized cells such as epithelial cells, many GPI-APs are exclusively expressed in the apical surfaces, whereas some GPI-APs are preferentially expressed in the basolateral surfaces. Several GPI-APs act as transcytotic transporters carrying their ligands from one compartment to another. Some GPI-APs are shed from the membrane after cleavage within the GPI by a GPI-specific phospholipase or a glycosidase. In this review, I will summarize the current understanding of GPI-AP biosynthesis in mammalian cells and discuss examples of GPI-dependent functions of mammalian GPI-APs.
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Affiliation(s)
- Taroh Kinoshita
- Yabumoto Department of Intractable Disease Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, Japan
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18
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Sah SK, Shefali S, Yadav A, Som P, Komath SS. The caspase-like Gpi8 subunit of Candida albicans GPI transamidase is a metal-dependent endopeptidase. Biochem Biophys Res Commun 2020; 525:S0006-291X(20)30268-0. [PMID: 32081427 DOI: 10.1016/j.bbrc.2020.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 02/03/2020] [Indexed: 10/25/2022]
Abstract
GPI anchored proteins (GPI-APs) act at the frontiers of cells, decoding environmental cues and determining host-pathogen interactions in several lower eukaryotes. They are also essential for viability in lower eukaryotes. The GPI biosynthetic pathway begins at the ER and follows a roughly linear pathway to generate the complete precursor (CP) glycolipid. The GPI transamidase (GPIT) transfers this glycolipid to the C-terminal end of newly translated proteins after removing their GPI attachment signal sequence (SS). The GPIT subunit that cleaves SS is Gpi8, a protein with a conserved Cys/His catalytic dyad typical of cysteine proteases. A CaGPI8 heterozygous mutant accumulates CPs and has reduced cell surface GPI-APs. Using a simple cell-free assay, we demonstrate that the heterozygous CaGPI8 strain has low endopeptidase activity as well. The revertant strain is restored in all these phenotypes. CaGpi8 is also shown to be a metalloenzyme, whose protease activity is sensitive to agents that modify Cys/His residues.
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Affiliation(s)
- Sudisht Kumar Sah
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Shailja Shefali
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Anshuman Yadav
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Punnag Som
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sneha Sudha Komath
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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19
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Mersha FB, Cortes LK, Luck AN, McClung CM, Ruse CI, Taron CH, Foster JM. Computational and experimental analysis of the glycophosphatidylinositol-anchored proteome of the human parasitic nematode Brugia malayi. PLoS One 2019; 14:e0216849. [PMID: 31513600 PMCID: PMC6742230 DOI: 10.1371/journal.pone.0216849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/20/2019] [Indexed: 12/05/2022] Open
Abstract
Further characterization of essential systems in the parasitic filarial nematode Brugia malayi is needed to better understand its biology, its interaction with its hosts, and to identify critical components that can be exploited to develop novel treatments. The production of glycophosphatidylinositol-anchored proteins (GPI-APs) is essential for eukaryotic cellular and physiological function. In addition, GPI-APs perform many important roles for cells. In this study, we characterized the B. malayi GPI-anchored proteome using both computational and experimental approaches. We used bioinformatic strategies to show the presence or absence of B. malayi GPI-AP biosynthetic pathway genes and to compile a putative B. malayi GPI-AP proteome using available prediction programs. We verified these in silico analyses using proteomics to identify GPI-AP candidates prepared from the surface of intact worms and from membrane enriched extracts. Our study represents the first description of the GPI-anchored proteome in B. malayi and lays the groundwork for further exploration of this essential protein modification as a target for novel anthelmintic therapeutic strategies.
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Affiliation(s)
- Fana B. Mersha
- New England Biolabs, Ipswich MA, United States of America
| | | | - Ashley N. Luck
- New England Biolabs, Ipswich MA, United States of America
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20
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Komath SS, Singh SL, Pratyusha VA, Sah SK. Generating anchors only to lose them: The unusual story of glycosylphosphatidylinositol anchor biosynthesis and remodeling in yeast and fungi. IUBMB Life 2019; 70:355-383. [PMID: 29679465 DOI: 10.1002/iub.1734] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 02/16/2018] [Accepted: 02/22/2018] [Indexed: 02/06/2023]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are present ubiquitously at the cell surface in all eukaryotes. They play a crucial role in the interaction of the cell with its external environment, allowing the cell to receive signals, respond to challenges, and mediate adhesion. In yeast and fungi, they also participate in the structural integrity of the cell wall and are often essential for survival. Roughly four decades after the discovery of the first GPI-APs, this review provides an overview of the insights gained from studies of the GPI biosynthetic pathway and the future challenges in the field. In particular, we focus on the biosynthetic pathway in Saccharomyces cerevisiae, which has for long been studied as a model organism. Where available, we also provide information about the GPI biosynthetic steps in other yeast/ fungi. Although the core structure of the GPI anchor is conserved across organisms, several variations are built into the biosynthetic pathway. The present Review specifically highlights these variations and their implications. There is growing evidence to suggest that several phenotypes are common to GPI deficiency and should be expected in GPI biosynthetic mutants. However, it appears that several phenotypes are unique to a specific step in the pathway and may even be species-specific. These could suggest the points at which the GPI biosynthetic pathway intersects with other important cellular pathways and could be points of regulation. They could be of particular significance in the study of pathogenic fungi and in identification of new and specific antifungal drugs/ drug targets. © 2018 IUBMB Life, 70(5):355-383, 2018.
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Affiliation(s)
| | - Sneh Lata Singh
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | - Sudisht Kumar Sah
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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21
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Zhao M, Wang W, Chen W, Ma C, Zhang F, Jiang K, Liu J, Diao L, Qian H, Zhao J, Wang T, Ma L. Genome survey, high-resolution genetic linkage map construction, growth-related quantitative trait locus (QTL) identification and gene location in Scylla paramamosain. Sci Rep 2019; 9:2910. [PMID: 30814536 PMCID: PMC6393678 DOI: 10.1038/s41598-019-39070-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 01/11/2019] [Indexed: 11/09/2022] Open
Abstract
Scylla paramamosain is one of the most economically important crabs in China. In this study, the first genome survey sequencing of this crab was performed, and the results revealed that the estimated genome size was 1.21 Gb with high heterozygosity (1.3%). Then, RAD technology was used to construct a high-resolution linkage map for this species. A total of 24,444 single nucleotide polymorphism (SNP) makers were grouped into 47 linkage groups. The total length of the linkage groups was 3087.53 cM with a markers interval of 0.92 cM. With the aid of transcriptome and genome scaffold data, 4,271 markers were linked to genes, including several important growth-related genes such as transforming growth factor-beta regulator I, immune related-gene C-type lectin and ecdysone pathway gene broad-complex-like protein. Further, 442 markers, representing 279 QTLs, associated with 24 traits were identified, and of these markers, 78 were linked to genes. Some interesting genes, such as dedicator of cytokinesis protein 3, tenascin-X and DNA helicase MCM8, were believed to have important relationship with specific traits and merit further exploration. The results of this study will accelerate the genetic improvement and genome sequencing analysis of the mud crab.
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Affiliation(s)
- Ming Zhao
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Wei Wang
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Wei Chen
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Chunyan Ma
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Fengying Zhang
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Keji Jiang
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Junguo Liu
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Le Diao
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Heng Qian
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Junxia Zhao
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Tian Wang
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China
| | - Lingbo Ma
- East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 300 Jungong Road, Shanghai, 200090, China.
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22
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Wang Y, Hirata T, Maeda Y, Murakami Y, Fujita M, Kinoshita T. Free, unlinked glycosylphosphatidylinositols on mammalian cell surfaces revisited. J Biol Chem 2019; 294:5038-5049. [PMID: 30728244 DOI: 10.1074/jbc.ra119.007472] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 01/30/2019] [Indexed: 12/17/2022] Open
Abstract
Glycosylphosphatidylinositols (GPIs) are linked to many cell-surface proteins, anchor these proteins in the membrane, and are well characterized. However, GPIs that exist in the free form on the mammalian cell surface remain largely unexplored. To investigate free GPIs in cultured cell lines and mouse tissues, here we used the T5-4E10 mAb (T5 mAb), which recognizes unlinked GPIs having an N-acetylgalactosamine (GalNAc) side chain linked to the first mannose at the nonreducing terminus. We detected free GPIs bearing the GalNAc side chain on the surface of Neuro2a and CHO, but not of HEK293, K562, and C2C12 cells. Furthermore, free GPIs were present in mouse pons, medulla oblongata, spinal cord, testis, epididymis, and kidney. Using a panel of Chinese hamster ovary cells defective in both GPI-transamidase and GPI remodeling pathway, we demonstrate that free GPIs follow the same structural remodeling pathway during passage from the endoplasmic reticulum to the plasma membrane as do protein-linked GPI. Specifically, free GPIs underwent post-GPI attachment to protein 1 (PGAP1)-mediated inositol deacylation, PGAP5-mediated removal of the ethanolamine phosphate from the second mannose, and PGAP3- and PGAP2-mediated fatty acid remodeling. Moreover, T5 mAb recognized free GPIs even if the inositol-linked acyl chain or ethanolamine-phosphate side chain linked to the second mannose is not removed. In contrast, addition of a fourth mannose by phosphatidylinositol glycan anchor biosynthesis class Z (PIGZ) inhibited T5 mAb-mediated detection of free GPIs. Our results indicate that free GPIs are normal components of the plasma membrane in some tissues and further characterize free GPIs in mammalian cells.
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Affiliation(s)
- Yicheng Wang
- From the Research Institute for Microbial Diseases and.,World Premier International (WPI) Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan and
| | | | - Yusuke Maeda
- From the Research Institute for Microbial Diseases and
| | - Yoshiko Murakami
- From the Research Institute for Microbial Diseases and.,World Premier International (WPI) Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan and
| | - Morihisa Fujita
- the Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Taroh Kinoshita
- From the Research Institute for Microbial Diseases and .,World Premier International (WPI) Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan and
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23
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Yamamoto-Hino M, Katsumata E, Suzuki E, Maeda Y, Kinoshita T, Goto S. Nuclear envelope localization of PIG-B is essential for GPI-anchor synthesis in Drosophila. J Cell Sci 2018; 131:jcs.218024. [PMID: 30266758 PMCID: PMC6215393 DOI: 10.1242/jcs.218024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 09/21/2018] [Indexed: 12/14/2022] Open
Abstract
Membrane lipid biosynthesis is a complex process that takes place in various intracellular compartments. Glycosylphosphatidylinositol (GPI), a lipid involved in membrane anchoring of some proteins, is synthesized by the PIG enzymes. Most PIGs are localized to the endoplasmic reticulum (ER), but Drosophila PIG-B (DmPIG-B) is localized to the nuclear envelope (NE). To determine whether the NE localization of DmPIG-B is functionally important, we defined the determinants of localization and generated an ER-localized form, denoted DmPIG-B[ER]. The enzymatic activity of DmPIG-B[ER] was comparable to that of NE-localized DmPIG-B[NE]. Expression of DmPIG-B[ER] inefficiently rescued the lethality of the PIG-B mutant, whereas DmPIG-B[NE] rescued this lethality fully. DmPIG-B[ER] was preferentially degraded by lysosomes, suggesting that the NE localization is essential for function and stability of the protein. In addition, we found that the region of the ER proximal to the NE is the site of translation of GPI-anchored proteins and addition of GPI. Thus, the NE and proximal ER may provide a platform for efficient GPI anchoring. Summary: In Drosophila, localization of the enzyme PIG-B in the nuclear envelope (NE) is important for GPI anchor synthesis, and the NE and the perinuclear ER form a platform for the GPI modification.
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Affiliation(s)
- Miki Yamamoto-Hino
- Department of Life Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
| | - Eri Katsumata
- Department of Life Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
| | - Emiko Suzuki
- Gene Network Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Yusuke Maeda
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Taroh Kinoshita
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Satoshi Goto
- Department of Life Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
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24
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Müller GA. The release of glycosylphosphatidylinositol-anchored proteins from the cell surface. Arch Biochem Biophys 2018; 656:1-18. [DOI: 10.1016/j.abb.2018.08.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/07/2018] [Accepted: 08/14/2018] [Indexed: 12/15/2022]
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25
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Jain P, Sethi SC, Pratyusha VA, Garai P, Naqvi N, Singh S, Pawar K, Puri N, Komath SS. Ras signaling activates glycosylphosphatidylinositol (GPI) anchor biosynthesis via the GPI- N-acetylglucosaminyltransferase (GPI-GnT) in Candida albicans. J Biol Chem 2018; 293:12222-12238. [PMID: 29907567 DOI: 10.1074/jbc.ra117.001225] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/17/2018] [Indexed: 01/08/2023] Open
Abstract
The ability of Candida albicans to switch between yeast to hyphal form is a property that is primarily associated with the invasion and virulence of this human pathogenic fungus. Several glycosylphosphatidylinositol (GPI)-anchored proteins are expressed only during hyphal morphogenesis. One of the major pathways that controls hyphal morphogenesis is the Ras-signaling pathway. We examine the cross-talk between GPI anchor biosynthesis and Ras signaling in C. albicans. We show that the first step of GPI biosynthesis is activated by Ras in C. albicans This is diametrically opposite to what is reported in Saccharomyces cerevisiae Of the two C. albicans Ras proteins, CaRas1 alone activates GPI-GnT activity; activity is further stimulated by constitutively activated CaRas1. CaRas1 localized to the cytoplasm or endoplasmic reticulum (ER) is sufficient for GPI-GnT activation. Of the six subunits of the GPI-N-acetylglucosaminyltransferase (GPI-GnT) that catalyze the first step of GPI biosynthesis, CaGpi2 is the key player involved in activating Ras signaling and hyphal morphogenesis. Activation of Ras signaling is independent of the catalytic competence of GPI-GnT. This too is unlike what is observed in S. cerevisiae where multiple subunits were identified as inhibiting Ras2. Fluorescence resonance energy transfer (FRET) studies indicate a specific physical interaction between CaRas1 and CaGpi2 in the ER, which would explain the ability of CaRas1 to activate GPI-GnT. CaGpi2, in turn, promotes activation of the Ras-signaling pathway and hyphal morphogenesis. The Cagpi2 mutant is also more susceptible to macrophage-mediated killing, and macrophage cells show better survival when co-cultured with Cagpi2.
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Affiliation(s)
- Priyanka Jain
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | | | | | - Pramita Garai
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Nilofer Naqvi
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Sonali Singh
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Kalpana Pawar
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Niti Puri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Sneha Sudha Komath
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India.
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Eisenhaber B, Sinha S, Wong WC, Eisenhaber F. Function of a membrane-embedded domain evolutionarily multiplied in the GPI lipid anchor pathway proteins PIG-B, PIG-M, PIG-U, PIG-W, PIG-V, and PIG-Z. Cell Cycle 2018; 17:874-880. [PMID: 29764287 PMCID: PMC6056205 DOI: 10.1080/15384101.2018.1456294] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Distant homology relationships among proteins with many transmembrane regions (TMs) are difficult to detect as they are clouded by the TMs’ hydrophobic compositional bias and mutational divergence in connecting loops. In the case of several GPI lipid anchor biosynthesis pathway components, the hidden evolutionary signal can be revealed with dissectHMMER, a sequence similarity search tool focusing on fold-critical, high complexity sequence segments. We find that a sequence module with 10 TMs in PIG-W, described as acyl transferase, is homologous to PIG-U, a transamidase subunit without characterized molecular function, and to mannosyltransferases PIG-B, PIG-M, PIG-V and PIG-Z. We conclude that this new, membrane-embedded domain named BindGPILA functions as the unit for recognizing, binding and stabilizing the GPI lipid anchor in a modification-competent form as this appears the only functional aspect shared among all proteins. Thus, PIG-U's likely molecular function is shuttling/presenting the anchor in a productive conformation to the transamidase complex.
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Affiliation(s)
- Birgit Eisenhaber
- a Bioinformatics Institute, Agency for Science , Technology and Research (A*STAR) , 30 Biopolis Street, #07-01 Matrix, Singapore 138671 , Republic of Singapore
| | - Swati Sinha
- a Bioinformatics Institute, Agency for Science , Technology and Research (A*STAR) , 30 Biopolis Street, #07-01 Matrix, Singapore 138671 , Republic of Singapore
| | - Wing-Cheong Wong
- a Bioinformatics Institute, Agency for Science , Technology and Research (A*STAR) , 30 Biopolis Street, #07-01 Matrix, Singapore 138671 , Republic of Singapore
| | - Frank Eisenhaber
- a Bioinformatics Institute, Agency for Science , Technology and Research (A*STAR) , 30 Biopolis Street, #07-01 Matrix, Singapore 138671 , Republic of Singapore.,b School of Computer Engineering , Nanyang Technological University (NTU) , 50 Nanyang Drive, Singapore 637553 , Republic of Singapore
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27
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Hirata T, Mishra SK, Nakamura S, Saito K, Motooka D, Takada Y, Kanzawa N, Murakami Y, Maeda Y, Fujita M, Yamaguchi Y, Kinoshita T. Identification of a Golgi GPI-N-acetylgalactosamine transferase with tandem transmembrane regions in the catalytic domain. Nat Commun 2018; 9:405. [PMID: 29374258 PMCID: PMC5785973 DOI: 10.1038/s41467-017-02799-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 12/28/2017] [Indexed: 12/31/2022] Open
Abstract
Many eukaryotic proteins are anchored to the cell surface via the glycolipid glycosylphosphatidylinositol (GPI). Mammalian GPIs have a conserved core but exhibit diverse N-acetylgalactosamine (GalNAc) modifications, which are added via a yet unresolved process. Here we identify the Golgi-resident GPI-GalNAc transferase PGAP4 and show by mass spectrometry that PGAP4 knockout cells lose GPI-GalNAc structures. Furthermore, we demonstrate that PGAP4, in contrast to known Golgi glycosyltransferases, is not a single-pass membrane protein but contains three transmembrane domains, including a tandem transmembrane domain insertion into its glycosyltransferase-A fold as indicated by comparative modeling. Mutational analysis reveals a catalytic site, a DXD-like motif for UDP-GalNAc donor binding, and several residues potentially involved in acceptor binding. We suggest that a juxtamembrane region of PGAP4 accommodates various GPI-anchored proteins, presenting their acceptor residue toward the catalytic center. In summary, we present insights into the structure of PGAP4 and elucidate the initial step of GPI-GalNAc biosynthesis.
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Affiliation(s)
- Tetsuya Hirata
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
- WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, 565-0871, Japan
- National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
| | - Sushil K Mishra
- Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN Global Research Cluster, Wako, Saitama, 351-0198, Japan
| | - Shota Nakamura
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Kazunobu Saito
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Daisuke Motooka
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Yoko Takada
- WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Noriyuki Kanzawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
- WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Yoshiko Murakami
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
- WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Yusuke Maeda
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
- WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Yoshiki Yamaguchi
- Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN Global Research Cluster, Wako, Saitama, 351-0198, Japan
| | - Taroh Kinoshita
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan.
- WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, 565-0871, Japan.
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28
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Kinoshita T, Fujita M. Biosynthesis of GPI-anchored proteins: special emphasis on GPI lipid remodeling. J Lipid Res 2015; 57:6-24. [PMID: 26563290 DOI: 10.1194/jlr.r063313] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Indexed: 02/06/2023] Open
Abstract
Glycosylphosphatidylinositols (GPIs) act as membrane anchors of many eukaryotic cell surface proteins. GPIs in various organisms have a common backbone consisting of ethanolamine phosphate (EtNP), three mannoses (Mans), one non-N-acetylated glucosamine, and inositol phospholipid, whose structure is EtNP-6Manα-2Manα-6Manα-4GlNα-6myoinositol-P-lipid. The lipid part is either phosphatidylinositol of diacyl or 1-alkyl-2-acyl form, or inositol phosphoceramide. GPIs are attached to proteins via an amide bond between the C-terminal carboxyl group and an amino group of EtNP. Fatty chains of inositol phospholipids are inserted into the outer leaflet of the plasma membrane. More than 150 different human proteins are GPI anchored, whose functions include enzymes, adhesion molecules, receptors, protease inhibitors, transcytotic transporters, and complement regulators. GPI modification imparts proteins with unique characteristics, such as association with membrane microdomains or rafts, transient homodimerization, release from the membrane by cleavage in the GPI moiety, and apical sorting in polarized cells. GPI anchoring is essential for mammalian embryogenesis, development, neurogenesis, fertilization, and immune system. Mutations in genes involved in remodeling of the GPI lipid moiety cause human diseases characterized by neurological abnormalities. Yeast Saccharomyces cerevisiae has >60 GPI-anchored proteins (GPI-APs). GPI is essential for growth of yeast. In this review, we discuss biosynthesis of GPI-APs in mammalian cells and yeast with emphasis on the lipid moiety.
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Affiliation(s)
- Taroh Kinoshita
- WPI Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
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29
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Krüger AT, Engel J, Buettner FFR, Routier FH. Aspergillus fumigatus Cap59-like protein A is involved in α1,3-mannosylation of GPI-anchors. Glycobiology 2015; 26:30-8. [PMID: 26369907 DOI: 10.1093/glycob/cwv078] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/09/2015] [Indexed: 01/06/2023] Open
Abstract
Glycosylphosphatidylinositol (GPI) attaches a variety of eukaryotic proteins to the outer leaflet of the plasma membrane. In fungi, these proteins may also be transferred to the cell wall, to which they are covalently linked via a remnant of the GPI-anchor. They play crucial physiological roles in cell-cell interactions, adhesion or cell wall biogenesis. The biosynthesis of GPI-anchors in the endoplasmic reticulum, their transfer to proteins, early remodelling and transport to the Golgi apparatus has been fairly well described. In contrast, almost nothing is known about the genes and enzymes involved in adding glycan side chains to GPI after protein attachment. In this study, we characterized an α1,3-mannosyltransferase involved in maturation of GPI-anchors from the pathogenic fungus Aspergillus fumigatus. This enzyme shows homology to Cryptococcus neoformans Cap59p, a putative glycosyltransferase involved in capsule formation and virulence, and was thus named Cap59-like protein A (ClpA). Targeted deletion of the clpA gene in A. fumigatus led to absence of α1,3-mannose from mature GPI-anchors. The enzyme was further located to the Golgi-like apparatus of A. fumigatus and was shown to be active in the yeast Saccharomyces cerevisiae.
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Affiliation(s)
- Anke Tina Krüger
- Department of Cellular Chemistry OE 4330, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Jakob Engel
- Department of Cellular Chemistry OE 4330, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Falk F R Buettner
- Department of Cellular Chemistry OE 4330, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Françoise H Routier
- Department of Cellular Chemistry OE 4330, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
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30
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Davis EM, Kim J, Menasche BL, Sheppard J, Liu X, Tan AC, Shen J. Comparative Haploid Genetic Screens Reveal Divergent Pathways in the Biogenesis and Trafficking of Glycophosphatidylinositol-Anchored Proteins. Cell Rep 2015; 11:1727-36. [PMID: 26074080 DOI: 10.1016/j.celrep.2015.05.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 04/17/2015] [Accepted: 05/11/2015] [Indexed: 11/30/2022] Open
Abstract
Glycophosphatidylinositol-anchored proteins (GPI-APs) play essential roles in physiology, but their biogenesis and trafficking have not been systematically characterized. Here, we took advantage of the recently available haploid genetics approach to dissect GPI-AP pathways in human cells using prion protein (PrP) and CD59 as model molecules. Our screens recovered a large number of common and unexpectedly specialized factors in the GPI-AP pathways. PIGN, PGAP2, and PIGF, which encode GPI anchor-modifying enzymes, were selectively isolated in the CD59 screen, suggesting that GPI anchor composition significantly influences the biogenesis of GPI-APs in a substrate-dependent manner. SEC62 and SEC63, which encode components of the ER-targeting machinery, were selectively recovered in the PrP screen, indicating that they do not constitute a universal route for the biogenesis of mammalian GPI-APs. Together, these comparative haploid genetic screens demonstrate that, despite their similarity in overall architecture and subcellular localization, GPI-APs follow markedly distinct biosynthetic and trafficking pathways.
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Affiliation(s)
- Eric M Davis
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Jihye Kim
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Bridget L Menasche
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Jacob Sheppard
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Xuedong Liu
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Aik-Choon Tan
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jingshi Shen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA.
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31
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Comparative Analysis of Protein Glycosylation Pathways in Humans and the Fungal Pathogen Candida albicans. Int J Microbiol 2014; 2014:267497. [PMID: 25104959 PMCID: PMC4106090 DOI: 10.1155/2014/267497] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 06/06/2014] [Indexed: 11/30/2022] Open
Abstract
Protein glycosylation pathways are present in all kingdoms of life and are metabolic pathways found in all the life kingdoms. Despite sharing commonalities in their synthesis, glycans attached to glycoproteins have species-specific structures generated by the presence of different sets of enzymes and acceptor substrates in each organism. In this review, we present a comparative analysis of the main glycosylation pathways shared by humans and the fungal pathogen Candida albicans: N-linked glycosylation, O-linked mannosylation and glycosylphosphatidylinositol-anchorage. The knowledge of similarities and divergences between these metabolic pathways could help find new pharmacological targets for C. albicans infection.
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32
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Cortes LK, Scarcelli JJ, Taron CH. Complementation of essential yeast GPI mannosyltransferase mutations suggests a novel specificity for certain Trypanosoma and Plasmodium PigB proteins. PLoS One 2014; 9:e87673. [PMID: 24489949 PMCID: PMC3906172 DOI: 10.1371/journal.pone.0087673] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 12/27/2013] [Indexed: 11/25/2022] Open
Abstract
The glycosylphosphatidylinositol (GPI) anchor is an essential glycolipid that tethers certain eukaryotic proteins to the cell surface. The core structure of the GPI anchor is remarkably well conserved across evolution and consists of NH2-CH2-CH2-PO4-6Manα1,2Manα1,6Manα1,4-GlcNα1,6-myo-inositol-PO4-lipid. The glycan portion of this structure may be modified with various side-branching sugars or other compounds that are heterogeneous and differ from organism to organism. One such modification is an α(1,2)-linked fourth mannose (Man-IV) that is side-branched to the third mannose (Man-III) of the trimannosyl core. In fungi and mammals, addition of Man-III and Man-IV occurs by two distinct Family 22 α(1,2)-mannosyltransferases, Gpi10/PigB and Smp3/PigZ, respectively. However, in the five protozoan parasite genomes we examined, no genes encoding Smp3/PigZ proteins were observed, despite reports of tetramannosyl-GPI structures (Man4-GPIs) being produced by some parasites. In this study, we tested the hypothesis that the Gpi10/PigB proteins produced by protozoan parasites have the ability to add both Man-III and Man-IV to GPI precursors. We used yeast genetics to test the in vivo specificity of Gpi10/PigB proteins from several Plasmodium and Trypanosoma species by examining their ability to restore viability to Saccharomyces cerevisiae strains harboring lethal defects in Man-III (gpi10Δ) or Man-IV (smp3Δ) addition to GPI precursor lipids. We demonstrate that genes encoding PigB enzymes from T. cruzi, T. congolense and P. falciparum are each capable of separately complementing essential gpi10Δ and smp3Δ mutations, while PIGB genes from T. vivax and T. brucei only complement gpi10Δ. Additionally, we show the ability of T. cruzi PIGB to robustly complement a gpi10Δ/smp3Δ double mutant. Our data suggest that certain Plasmodium and Trypanosoma PigB mannosyltransferases can transfer more than one mannose to GPI precursors in vivo, and suggest a novel biosynthetic mechanism by which Man4-GPIs may be synthesized in these organisms.
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Affiliation(s)
- Leslie K. Cortes
- New England Biolabs, Ipswich, Massachusetts, United States of America
| | - John J. Scarcelli
- New England Biolabs, Ipswich, Massachusetts, United States of America
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Gamage DG, Hendrickson TL. GPI Transamidase and GPI anchored proteins: Oncogenes and biomarkers for cancer. Crit Rev Biochem Mol Biol 2013; 48:446-64. [DOI: 10.3109/10409238.2013.831024] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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34
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Hirata T, Fujita M, Kanzawa N, Murakami Y, Maeda Y, Kinoshita T. Glycosylphosphatidylinositol mannosyltransferase II is the rate-limiting enzyme in glycosylphosphatidylinositol biosynthesis under limited dolichol-phosphate mannose availability. J Biochem 2013; 154:257-64. [PMID: 23694781 DOI: 10.1093/jb/mvt045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Although the genes involved in the biosynthesis of glycosylphosphatidylinositol (GPI) are well characterized, the regulation of GPI biosynthesis remains unclear. We isolated and characterized a mutant cell line showing decreased surface expression of CD59 and the accumulation of GPI intermediates. The mutant cell line was partially defective in MPDU1, which encodes a protein required for the utilization of dolichol-phosphate mannose. Overexpression of PIGV, which encodes GPI mannosyltransferase II, restored the surface expression of CD59 and normalized the accumulation of GPI intermediates in the mutant cells. Among all known genes involved in GPI biosynthetic pathway, only PIGV had such suppressive activity. PIGV, however, did not restore the abnormality of N-glycosylation caused by MPDU1 mutation. Our results suggest that GPI mannosyltransferase II is the rate-limiting enzyme in GPI biosynthesis under limited dolichol-phosphate mannose availability.
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Affiliation(s)
- Tetsuya Hirata
- Research Institute for Microbial Diseases and WPI Immunology Frontier Research Center, Osaka University, Osaka 565-0871, Japan
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35
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Yang H, Lee SE, Lee S, Cho JJ, Ahn HJ, Park CS, Park YS. Integrated analysis of miRNA and mRNA reveals that acrolein modulates GPI anchor biosynthesis in human primary endothelial cells. BIOCHIP JOURNAL 2013. [DOI: 10.1007/s13206-013-7103-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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36
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In vivo incorporation of an azide-labeled sugar analog to detect mammalian glycosylphosphatidylinositol molecules isolated from the cell surface. Carbohydr Res 2012; 362:62-9. [PMID: 23085221 DOI: 10.1016/j.carres.2012.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 09/11/2012] [Accepted: 09/13/2012] [Indexed: 11/22/2022]
Abstract
N-Acetylgalactosamine (GalNAc) linked to the first mannose of glycosylphosphatidylinositol (GPI) core has been previously reported to be heterogeneously present on some mammalian GPI-anchored proteins. Here we present a method for profiling GalNAc-containing GPI-anchored proteins in mammalian cells by metabolic labeling with tetraacetylated N-azidoacetylgalactosamine (GalNAz) followed by biotinylation of the incorporated sugar analog. We have labeled both endogenous and recombinant GPI-anchored proteins with GalNAz, and demonstrated that the azide-activated sugar gets incorporated into the GPI glycan, likely as an unsubstituted side branch of the core structure. GalNAz was detected only on GPI molecules attached to proteins, and not on GPI precursors, indicating that GalNAc modification takes place after the GPI anchor is transferred to protein. We have highlighted the utility of this cell labeling approach by demonstrating the ability to examine specific GalNAc-containing GPI-anchored proteins isolated non-destructively from separate membrane domains (apical and basolateral) in polarized epithelial cells. This study represents the first demonstration of site-specific in vivo labeling of a GPI moiety with a synthetic sugar analog.
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Fujita M, Kinoshita T. GPI-anchor remodeling: Potential functions of GPI-anchors in intracellular trafficking and membrane dynamics. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1050-8. [DOI: 10.1016/j.bbalip.2012.01.004] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 12/28/2011] [Accepted: 01/04/2012] [Indexed: 01/08/2023]
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38
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Scarcelli JJ, Colussi PA, Fabre AL, Boles E, Orlean P, Taron CH. Uptake of radiolabeled GlcNAc into Saccharomyces cerevisiae via native hexose transporters and its in vivo incorporation into GPI precursors in cells expressing heterologous GlcNAc kinase. FEMS Yeast Res 2012; 12:305-16. [PMID: 22151002 PMCID: PMC3498731 DOI: 10.1111/j.1567-1364.2011.00778.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 11/28/2011] [Accepted: 11/29/2011] [Indexed: 11/29/2022] Open
Abstract
Yeast glycan biosynthetic pathways are commonly studied through metabolic incorporation of an exogenous radiolabeled compound into a target glycan. In Saccharomyces cerevisiae glycosylphosphatidylinositol (GPI) biosynthesis, [3H]inositol has been widely used to identify intermediates that accumulate in conditional GPI synthesis mutants. However, this approach also labels non-GPI lipid species that overwhelm detection of early GPI intermediates during chromatography. In this study, we show that despite lacking the ability to metabolize N-acetylglucosamine (GlcNAc), S. cerevisiae is capable of importing low levels of extracellular GlcNAc via almost all members of the hexose transporter family. Furthermore, expression of a heterologous GlcNAc kinase gene permits efficient incorporation of exogenous [14C]GlcNAc into nascent GPI structures in vivo, dramatically lowering the background signal from non-GPI lipids. Utilizing this new method with several conditional GPI biosynthesis mutants, we observed and characterized novel accumulating lipids that were not previously visible using [3H]inositol labeling. Chemical and enzymatic treatments of these lipids indicated that each is a GPI intermediate likely having one to three mannoses and lacking ethanolamine phosphate (Etn-P) side-branches. Our data support a model of yeast GPI synthesis that bifurcates after the addition of the first mannose and that includes a novel branch that produces GPI species lacking Etn-P side-branches.
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39
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Structural remodeling, trafficking and functions of glycosylphosphatidylinositol-anchored proteins. Prog Lipid Res 2011; 50:411-24. [PMID: 21658410 DOI: 10.1016/j.plipres.2011.05.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Glycosylphosphatidylinositol (GPI) is a glycolipid that is covalently attached to proteins as a post-translational modification. Such modification leads to the anchoring of the protein to the outer leaflet of the plasma membrane. Proteins that are decorated with GPIs have unique properties in terms of their physical nature. In particular, these proteins tend to accumulate in lipid rafts, which are critical for the functions and trafficking of GPI-anchored proteins (GPI-APs). Recent studies mainly using mutant cells revealed that various structural remodeling reactions occur to GPIs present in GPI-APs as they are transported from the endoplasmic reticulum to the cell surface. This review examines the recent progress describing the mechanisms of structural remodeling of mammalian GPI-anchors, such as inositol deacylation, glycan remodeling and fatty acid remodeling, with particular focus on their trafficking and functions, as well as the pathogenesis involving GPI-APs and their deficiency.
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40
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Toyn JH, Lin XA, Thompson MW, Guss V, Meredith JE, Sankaranarayanan S, Barrezueta N, Corradi J, Majumdar A, Small DL, Hansard M, Lanthorn T, Westphal RS, Albright CF. Viable mouse gene ablations that robustly alter brain Aβ levels are rare. BMC Neurosci 2010; 11:143. [PMID: 21054826 PMCID: PMC2988800 DOI: 10.1186/1471-2202-11-143] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 11/05/2010] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Accumulation of amyloid-β (Aβ) peptide in the brain is thought to play a key pathological role in Alzheimer's disease. Many pharmacological targets have therefore been proposed based upon the biochemistry of Aβ, but not all are equally tractable for drug discovery. RESULTS To search for novel targets that affect brain Aβ without causing toxicity, we screened mouse brain samples from 1930 novel gene knock-out (KO) strains, representing 1926 genes, using Aβ ELISA assays. Although robust Aβ lowering was readily apparent in brains from a BACE1 KO strain, none of the novel strains exhibited robust decreases in brain Aβ, including a GPR3 KO strain, which had previously been proposed as an Aβ target. However, significantly increased Aβ was observed in brain samples from two KO strains, corresponding to genes encoding the glycosylphosphatidylinositol mannosyl transferase PIGZ and quinolinate phosphoribosyltransferase (QPRT). CONCLUSIONS Thus, gene ablations that are permissive for mouse survival and that also have a robust effect on Aβ levels in the brain are rare.
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Affiliation(s)
- Jeremy H Toyn
- Neuroscience Biology, Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, USA.
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Chapter 1 Overview of GPI Biosynthesis. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/s1874-6047(09)26001-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Izquierdo L, Nakanishi M, Mehlert A, Machray G, Barton GJ, Ferguson MAJ. Identification of a glycosylphosphatidylinositol anchor-modifying beta1-3 N-acetylglucosaminyl transferase in Trypanosoma brucei. Mol Microbiol 2008; 71:478-91. [PMID: 19040631 DOI: 10.1111/j.1365-2958.2008.06542.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Trypanosoma brucei expresses complex glycoproteins throughout its life cycle. A review of its repertoire of glycosidic linkages suggests a minimum of 38 glycosyltransferase activities. Of these, five have been experimentally related to specific genes and a further nine can be associated with candidate genes. The remaining linkages have no obvious candidate glycosyltransferase genes; however, the T. brucei genome contains a family of 21 putative UDP sugar-dependent glycosyltransferases of unknown function. One representative, TbGT8, was used to establish a functional characterization workflow. Bloodstream and procyclic-form TbGT8 null mutants were created and both exhibited normal growth. The major surface glycoprotein of the procyclic form, the procyclin, exhibited a marked reduction in molecular weight due to changes in the procyclin glycosylphosphatidylinositol (GPI) anchor side-chains. Structural analysis of the mutant procyclin GPI anchors indicated that TbGT8 encodes a UDP-GlcNAc: beta-Gal-GPI beta1-3 GlcNAc transferase. This is only the second GPI-modifying glycosyltransferase to have been identified from any organism. The glycosylation of the major glycoprotein of bloodstream-form T. brucei, the variant surface glycoprotein, was unaffected in the TbGT8 mutant. However, changes in the lectin binding of other glycoproteins suggest that TbGT8 influences the processing of the poly N-acetyllactosamine-containing asparagine-linked glycans of this life cycle stage.
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Affiliation(s)
- Luis Izquierdo
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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Kinoshita T, Fujita M, Maeda Y. Biosynthesis, remodelling and functions of mammalian GPI-anchored proteins: recent progress. J Biochem 2008; 144:287-94. [PMID: 18635593 DOI: 10.1093/jb/mvn090] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
More than 100 mammalian proteins are post-translationally modified by glycosylphosphatidylinositol (GPI) at their C-termini and are anchored to the cell surface membrane via the lipid portion. GPI-anchored proteins (GPI-APs) have various functions, such as hydrolytic enzymes, receptors, adhesion molecules, complement regulatory proteins and other immunologically important proteins. GPI-anchored proteins are mainly associated with membrane microdomains or membrane rafts enriched in sphingolipids and cholesterol. It is thought that association with membrane rafts is important for GPI-APs in signal transduction and other functions. Here, we review recent progress in studies on biosynthesis, remodelling and functions of mammalian GPI-APs.
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Affiliation(s)
- Taroh Kinoshita
- WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan.
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Maeda Y, Kinoshita T. Dolichol-phosphate mannose synthase: Structure, function and regulation. Biochim Biophys Acta Gen Subj 2008; 1780:861-8. [DOI: 10.1016/j.bbagen.2008.03.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 02/11/2008] [Accepted: 03/06/2008] [Indexed: 11/30/2022]
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Sato K, Noda Y, Yoda K. Pga1 is an essential component of Glycosylphosphatidylinositol-mannosyltransferase II of Saccharomyces cerevisiae. Mol Biol Cell 2007; 18:3472-85. [PMID: 17615295 PMCID: PMC1951765 DOI: 10.1091/mbc.e07-03-0258] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The Saccharomyces cerevisiae essential gene YNL158w/PGA1 encodes an endoplasmic reticulum (ER)-localized membrane protein. We constructed temperature-sensitive alleles of PGA1 by error-prone polymerase chain reaction mutagenesis to explore its biological role. Pulse-chase experiments revealed that the pga1(ts) mutants accumulated the ER-form precursor of Gas1 protein at the restrictive temperature. Transport of invertase and carboxypeptidase Y were not affected. Triton X-114 phase separation and [(3)H]inositol labeling indicated that the glycosylphosphatidylinositol (GPI)-anchoring was defective in the pga1(ts) mutants, suggesting that Pga1 is involved in GPI synthesis or its transfer to target proteins. We found GPI18, which was recently reported to encode GPI-mannosyltransferase II (GPI-MT II), as a high-copy suppressor of the temperature sensitivity of pga1(ts). Both Gpi18 and Pga1 were detected in the ER by immunofluorescence, and they were coprecipitated from the Triton X-100-solubilized membrane. The gpi18(ts) and pga1(ts) mutants accumulated the same GPI synthetic intermediate at the restrictive temperature. From these results, we concluded that Pga1 is an additional essential component of the yeast GPI-MT II.
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Affiliation(s)
- Keisuke Sato
- Department of Biotechnology, University of Tokyo, Tokyo 113-8657, Japan
| | - Yoichi Noda
- Department of Biotechnology, University of Tokyo, Tokyo 113-8657, Japan
| | - Koji Yoda
- Department of Biotechnology, University of Tokyo, Tokyo 113-8657, Japan
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Orlean P, Menon AK. Thematic review series: lipid posttranslational modifications. GPI anchoring of protein in yeast and mammalian cells, or: how we learned to stop worrying and love glycophospholipids. J Lipid Res 2007; 48:993-1011. [PMID: 17361015 DOI: 10.1194/jlr.r700002-jlr200] [Citation(s) in RCA: 275] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI) anchoring of cell surface proteins is the most complex and metabolically expensive of the lipid posttranslational modifications described to date. The GPI anchor is synthesized via a membrane-bound multistep pathway in the endoplasmic reticulum (ER) requiring >20 gene products. The pathway is initiated on the cytoplasmic side of the ER and completed in the ER lumen, necessitating flipping of a glycolipid intermediate across the membrane. The completed GPI anchor is attached to proteins that have been translocated across the ER membrane and that display a GPI signal anchor sequence at the C terminus. GPI proteins transit the secretory pathway to the cell surface; in yeast, many become covalently attached to the cell wall. Genes encoding proteins involved in all but one of the predicted steps in the assembly of the GPI precursor glycolipid and its transfer to protein in mammals and yeast have now been identified. Most of these genes encode polytopic membrane proteins, some of which are organized in complexes. The steps in GPI assembly, and the enzymes that carry them out, are highly conserved. GPI biosynthesis is essential for viability in yeast and for embryonic development in mammals. In this review, we describe the biosynthesis of mammalian and yeast GPIs, their transfer to protein, and their subsequent processing.
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Affiliation(s)
- Peter Orlean
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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Pittet M, Conzelmann A. Biosynthesis and function of GPI proteins in the yeast Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:405-20. [PMID: 16859984 DOI: 10.1016/j.bbalip.2006.05.015] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Revised: 05/20/2006] [Accepted: 05/22/2006] [Indexed: 11/28/2022]
Abstract
Like most other eukaryotes, Saccharomyces cerevisiae harbors a GPI anchoring machinery and uses it to attach proteins to membranes. While a few GPI proteins reside permanently at the plasma membrane, a majority of them gets further processed and is integrated into the cell wall by a covalent attachment to cell wall glucans. The GPI biosynthetic pathway is necessary for growth and survival of yeast cells. The GPI lipids are synthesized in the ER and added onto proteins by a pathway comprising 12 steps, carried out by 23 gene products, 19 of which are essential. Some of the estimated 60 GPI proteins predicted from the genome sequence serve enzymatic functions required for the biosynthesis and the continuous shape adaptations of the cell wall, others seem to be structural elements of the cell wall and yet others mediate cell adhesion. Because of its genetic tractability S. cerevisiae is an attractive model organism not only for studying GPI biosynthesis in general, but equally for investigating the intracellular transport of GPI proteins and the peculiar role of GPI anchoring in the elaboration of fungal cell walls.
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Affiliation(s)
- Martine Pittet
- Department of Medicine, Division of Biochemistry, Chemin du Musée 5, CH-1700 Fribourg, Switzerland
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Vainauskas S, Menon AK. Ethanolamine phosphate linked to the first mannose residue of glycosylphosphatidylinositol (GPI) lipids is a major feature of the GPI structure that is recognized by human GPI transamidase. J Biol Chem 2006; 281:38358-64. [PMID: 17060324 DOI: 10.1074/jbc.m608896200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI) anchoring of proteins is catalyzed by GPI transamidase (GPIT), a multisubunit, endoplasmic reticulum (ER)-localized enzyme. GPIT recognizes ER-translocated proteins that have a GPI-directing C-terminal signal sequence and replaces this sequence with a preassembled GPI anchor. Although the GPI signal sequence has been extensively characterized, little is known about the structural features of the GPI lipid substrate that enable its recognition by GPIT. In a previous study we showed that mature GPIs could be co-immunoprecipitated with GPIT complexes containing functional subunits (Vainauskas, S., and Menon, A. K. (2004) J. Biol. Chem. 279, 6540-6545). We now use this approach, as well as a method that reconstitutes the interaction between GPIs and GPIT, to define the basis of the interaction between GPI and human GPIT. We report that (i) human GPIT can interact with GPI biosynthetic intermediates, not just mature GPIs competent for transfer to protein, (ii) the ethanolamine phosphate group on the third mannose residue of the GPI glycan is not critical for GPI recognition by GPIT, (iii) the ethanolamine phosphate residue linked to the first mannose of the GPI structure is a major feature of GPIs that is recognized by human GPIT, and (iv) the simplest GPI recognized by human GPIT is EtN-P-2Manalpha1-4GlcN-(acyl)-phosphatidyl-inositol. These studies define the molecular characteristics of GPI that are recognized by GPIT and open the way to identifying GPIT subunits that are involved in this process.
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Affiliation(s)
- Saulius Vainauskas
- Department of Biochemistry, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA
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Morita YS, Sena CBC, Waller RF, Kurokawa K, Sernee MF, Nakatani F, Haites RE, Billman-Jacobe H, McConville MJ, Maeda Y, Kinoshita T. PimE is a polyprenol-phosphate-mannose-dependent mannosyltransferase that transfers the fifth mannose of phosphatidylinositol mannoside in mycobacteria. J Biol Chem 2006; 281:25143-55. [PMID: 16803893 DOI: 10.1074/jbc.m604214200] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphatidylinositol mannosides (PIMs) are a major class of glycolipids in all mycobacteria. AcPIM2, a dimannosyl PIM, is both an end product and a precursor for polar PIMs, such as hexamannosyl PIM (AcPIM6) and the major cell wall lipoglycan, lipoarabinomannan (LAM). The mannosyltransferases that convert AcPIM2 to AcPIM6 or LAM are dependent on polyprenol-phosphate-mannose (PPM), but have not yet been characterized. Here, we identified a gene, termed pimE that is present in all mycobacteria, and is required for AcPIM6 biosynthesis. PimE was initially identified based on homology with eukaryotic PIG-M mannosyltransferases. PimE-deleted Mycobacterium smegmatis was defective in AcPIM6 synthesis, and accumulated the tetramannosyl PIM, AcPIM4. Loss of PimE had no affect on cell growth or viability, or the biosynthesis of other intracellular and cell wall glycans. However, changes in cell wall hydrophobicity and plasma membrane organization were detected, suggesting a role for AcPIM6 in the structural integrity of the cell wall and plasma membrane. These defects were corrected by ectopic expression of the pimE gene. Metabolic pulse-chase radiolabeling and cell-free PIM biosynthesis assays indicated that PimE catalyzes the alpha1,2-mannosyl transfer for the AcPIM5 synthesis. Mutation of an Asp residue in PimE that is conserved in and required for the activity of human PIG-M resulted in loss of PIM-biosynthetic activity, indicating that PimE is the catalytic component. Finally, PimE was localized to a distinct membrane fraction enriched in AcPIM4-6 biosynthesis. Taken together, PimE represents the first PPM-dependent mannosyl-transferase shown to be involved in PIM biosynthesis, where it mediates the fifth mannose transfer.
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Affiliation(s)
- Yasu S Morita
- Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
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Abstract
Glycosylphosphatidylinositol (GPI) is used for anchoring many cell surface proteins to the plasma membrane. Biosynthesis of GPI anchor, its attachment to proteins, and modification of GPI-anchored proteins (GPI-APs) en route to the plasma membrane are complex processes (Ferguson, 1999; Kinoshita and Inoue, 2000). GPI-AP-defective mutant cell lines derived from CHO and other cells have been very useful in elucidating GPI biosynthetic pathway and cloning genes involved in these processes. In this chapter, we overview GPI-AP biosynthesis, establishment and characterization of GPI-AP-defective mutant cell lines, expression cloning using those mutant cells, and characteristics of GPI-AP-defective mutant cell lines.
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Affiliation(s)
- Yusuke Maeda
- Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Japan
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