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Tian S, Muneeruddin K, Choi MY, Tao L, Bhuiyan RH, Ohmi Y, Furukawa K, Furukawa K, Boland S, Shaffer SA, Adam RM, Dong M. Genome-wide CRISPR screens for Shiga toxins and ricin reveal Golgi proteins critical for glycosylation. PLoS Biol 2018; 16:e2006951. [PMID: 30481169 PMCID: PMC6258472 DOI: 10.1371/journal.pbio.2006951] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 10/02/2018] [Indexed: 12/15/2022] Open
Abstract
Glycosylation is a fundamental modification of proteins and membrane lipids. Toxins that utilize glycans as their receptors have served as powerful tools to identify key players in glycosylation processes. Here, we carried out Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9-mediated genome-wide loss-of-function screens using two related bacterial toxins, Shiga-like toxins (Stxs) 1 and 2, which use a specific glycolipid, globotriaosylceramide (Gb3), as receptors, and the plant toxin ricin, which recognizes a broad range of glycans. The Stxs screens identified major glycosyltransferases (GTs) and transporters involved in Gb3 biosynthesis, while the ricin screen identified GTs and transporters involved in N-linked protein glycosylation and fucosylation. The screens also identified lysosomal-associated protein transmembrane 4 alpha (LAPTM4A), a poorly characterized four-pass membrane protein, as a factor specifically required for Stxs. Mass spectrometry analysis of glycolipids and their precursors demonstrates that LAPTM4A knockout (KO) cells lack Gb3 biosynthesis. This requirement of LAPTM4A for Gb3 synthesis is not shared by its homolog lysosomal-associated protein transmembrane 4 beta (LAPTM4B), and switching the domains between them determined that the second luminal domain of LAPTM4A is required, potentially acting as a specific "activator" for the GT that synthesizes Gb3. These screens also revealed two Golgi proteins, Transmembrane protein 165 (TMEM165) and Transmembrane 9 superfamily member 2 (TM9SF2), as shared factors required for both Stxs and ricin. TMEM165 KO and TM9SF2 KO cells both showed a reduction in not only Gb3 but also other glycosphingolipids, suggesting that they are required for maintaining proper levels of glycosylation in general in the Golgi. In addition, TM9SF2 KO cells also showed defective endosomal trafficking. These studies reveal key Golgi proteins critical for regulating glycosylation and glycolipid synthesis and provide novel therapeutic targets for blocking Stxs and ricin toxicity.
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Affiliation(s)
- Songhai Tian
- Department of Urology, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Surgery, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Khaja Muneeruddin
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Mass Spectrometry Facility, University of Massachusetts Medical School, Shrewsbury, Massachusetts, United States of America
| | - Mei Yuk Choi
- Division of Genetics, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Liang Tao
- Department of Urology, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Surgery, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Robiul H. Bhuiyan
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Matsumoto, Kasugai, Aichi, Japan
| | - Yuhsuke Ohmi
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Matsumoto, Kasugai, Aichi, Japan
| | - Keiko Furukawa
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Matsumoto, Kasugai, Aichi, Japan
| | - Koichi Furukawa
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Matsumoto, Kasugai, Aichi, Japan
| | - Sebastian Boland
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Scott A. Shaffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Mass Spectrometry Facility, University of Massachusetts Medical School, Shrewsbury, Massachusetts, United States of America
| | - Rosalyn M. Adam
- Department of Urology, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Surgery, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Min Dong
- Department of Urology, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Department of Surgery, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
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Westman JS, Benktander J, Storry JR, Peyrard T, Hult AK, Hellberg Å, Teneberg S, Olsson ML. Identification of the Molecular and Genetic Basis of PX2, a Glycosphingolipid Blood Group Antigen Lacking on Globoside-deficient Erythrocytes. J Biol Chem 2015; 290:18505-18. [PMID: 26055721 DOI: 10.1074/jbc.m115.655308] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 11/06/2022] Open
Abstract
The x2 glycosphingolipid is expressed on erythrocytes from individuals of all common blood group phenotypes and elevated on cells of the rare P/P1/P(k)-negative p blood group phenotype. Globoside or P antigen is synthesized by UDP-N-acetylgalactosamine:globotriaosyl-ceramide 3-β-N-acetylgalactosaminyltransferase encoded by B3GALNT1. It is the most abundant non-acid glycosphingolipid on erythrocytes and displays the same terminal disaccharide, GalNAcβ3Gal, as x2. We encountered a patient with mutations in B3GALNT1 causing the rare P-deficient P1 (k) phenotype and whose pretransfusion plasma was unexpectedly incompatible with p erythrocytes. The same phenomenon was also noted in seven other unrelated P-deficient individuals. Thin-layer chromatography, mass spectrometry, and flow cytometry were used to show that the naturally occurring antibodies made by p individuals recognize x2 and sialylated forms of x2, whereas x2 is lacking on P-deficient erythrocytes. Overexpression of B3GALNT1 resulted in synthesis of both P and x2. Knockdown experiments with siRNA against B3GALNT1 diminished x2 levels. We conclude that x2 fulfills blood group criteria and is synthesized by UDP-N-acetylgalactosamine: globotriaosylceramide 3-β-N-acetylgalactosaminyltransferase. Based on this linkage, we proposed that x2 joins P in the GLOB blood group system (ISBT 028) and is renamed PX2 (GLOB2). Thus, in the absence of a functional P synthase, neither P nor PX2 are formed. As a consequence, naturally occurring anti-P and anti-PX2 can be made. Until the clinical significance of anti-PX2 is known, we also recommend that rare P1 (k) or P2 (k) erythrocyte units are preferentially selected for transfusion to P(k) patients because p erythrocytes may pose a risk for hemolytic transfusion reactions due to their elevated PX2 levels.
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Affiliation(s)
- Julia S Westman
- From the Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, SE-22184 Lund, Sweden
| | - John Benktander
- the Institute of Biomedicine, The Sahlgrenska Academy, Gothenburg University, SE-40530 Gothenburg, Sweden
| | - Jill R Storry
- From the Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, SE-22184 Lund, Sweden, the Clinical Immunology and Transfusion Medicine, Laboratory Medicine, Office of Medical Services, Region Skåne, SE-22185 Lund, Sweden
| | - Thierry Peyrard
- the Institut National de la Transfusion Sanguine (INTS), Département Centre National de Référence pour les Groupes Sanguins, F-75015 Paris, France, and the Laboratory of Excellence GR-Ex, F-75015 Paris, France
| | - Annika K Hult
- From the Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, SE-22184 Lund, Sweden, the Clinical Immunology and Transfusion Medicine, Laboratory Medicine, Office of Medical Services, Region Skåne, SE-22185 Lund, Sweden
| | - Åsa Hellberg
- From the Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, SE-22184 Lund, Sweden, the Clinical Immunology and Transfusion Medicine, Laboratory Medicine, Office of Medical Services, Region Skåne, SE-22185 Lund, Sweden
| | - Susann Teneberg
- the Institute of Biomedicine, The Sahlgrenska Academy, Gothenburg University, SE-40530 Gothenburg, Sweden,
| | - Martin L Olsson
- From the Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, SE-22184 Lund, Sweden, the Clinical Immunology and Transfusion Medicine, Laboratory Medicine, Office of Medical Services, Region Skåne, SE-22185 Lund, Sweden,
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Aryal RP, Ju T, Cummings RD. Identification of a novel protein binding motif within the T-synthase for the molecular chaperone Cosmc. J Biol Chem 2014; 289:11630-11641. [PMID: 24616093 DOI: 10.1074/jbc.m114.555870] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Prior studies suggested that the core 1 β3-galactosyltransferase (T-synthase) is a specific client of the endoplasmic reticulum chaperone Cosmc, whose function is required for T-synthase folding, activity, and consequent synthesis of normal O-glycans in all vertebrate cells. To explore whether the T-synthase encodes a specific recognition motif for Cosmc, we used deletion mutagenesis to identify a cryptic linear and relatively hydrophobic peptide in the N-terminal stem region of the T-synthase that is essential for binding to Cosmc (Cosmc binding region within T-synthase, or CBRT). Using this sequence information, we synthesized a peptide containing CBRT and found that it directly interacts with Cosmc and also inhibits Cosmc-assisted in vitro refolding of denatured T-synthase. Moreover, engineered T-synthase carrying mutations within CBRT exhibited diminished binding to Cosmc that resulted in the formation of inactive T-synthase. To confirm the general recognition of CBRT by Cosmc, we performed a domain swap experiment in which we inserted the stem region of the T-synthase into the human β4GalT1 and found that the CBRT element can confer Cosmc binding onto the β4GalT1 chimera. Thus, CBRT is a unique recognition motif for Cosmc to promote its regulation and formation of active T-synthase and represents the first sequence-specific chaperone recognition system in the ER/Golgi required for normal protein O-glycosylation.
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Affiliation(s)
- Rajindra P Aryal
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Tongzhong Ju
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322.
| | - Richard D Cummings
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322.
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Sethi MK, Buettner FFR, Ashikov A, Bakker H. In vitro assays of orphan glycosyltransferases and their application to identify Notch xylosyltransferases. Methods Mol Biol 2013; 1022:307-20. [PMID: 23765671 DOI: 10.1007/978-1-62703-465-4_23] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Here we describe a systematic approach to determine the activity of putative glycosyltransferases with a focus on orphan members of the glycosyltransferase 8 family. An assay that measures the hydrolysis activity of glycoslytransferases can indicate the donor nucleotide sugar specificity without previous knowledge about the acceptor. Knowing the donor specificity, the acceptor specificity can subsequently be determined using synthetic acceptors. Three putative glycosyltransferases, now renamed GXYLT1, GXYLT2, and XXYLT1, have been identified this way as xylosyltransferases and in addition have been shown to act on O-glucosylated EGF repeats of Notch.
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Affiliation(s)
- Maya K Sethi
- Department of Cellular Chemistry, Hannover Medical School, Hannover, Germany
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