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Kol I, Rishiq A, Cohen M, Kahlon S, Pick O, Dassa L, Stein N, Bar-On Y, Wolf DG, Seidel E, Mandelboim O. CLPTM1L is a GPI-anchoring pathway component targeted by HCMV. J Cell Biol 2023; 222:e202207104. [PMID: 37389656 PMCID: PMC10316631 DOI: 10.1083/jcb.202207104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 04/03/2023] [Accepted: 05/19/2023] [Indexed: 07/01/2023] Open
Abstract
The GPI-anchoring pathway plays important roles in normal development and immune modulation. MHC Class I Polypeptide-related Sequence A (MICA) is a stress-induced ligand, downregulated by human cytomegalovirus (HCMV) to escape immune recognition. Its most prevalent allele, MICA*008, is GPI-anchored via an uncharacterized pathway. Here, we identify cleft lip and palate transmembrane protein 1-like protein (CLPTM1L) as a GPI-anchoring pathway component and show that during infection, the HCMV protein US9 downregulates MICA*008 via CLPTM1L. We show that the expression of some GPI-anchored proteins (CD109, CD59, and MELTF)-but not others (ULBP2, ULBP3)-is CLPTM1L-dependent, and further show that like MICA*008, MELTF is downregulated by US9 via CLPTM1L during infection. Mechanistically, we suggest that CLPTM1L's function depends on its interaction with a free form of PIG-T, normally a part of the GPI transamidase complex. We suggest that US9 inhibits this interaction and thereby downregulates the expression of CLPTM1L-dependent proteins. Altogether, we report on a new GPI-anchoring pathway component that is targeted by HCMV.
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Affiliation(s)
- Inbal Kol
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Ahmed Rishiq
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Mevaseret Cohen
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Shira Kahlon
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Ophir Pick
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Liat Dassa
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Natan Stein
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Yotam Bar-On
- Department of Immunology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Dana G. Wolf
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
- Clinical Virology Unit, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Einat Seidel
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
| | - Ofer Mandelboim
- The Concern Foundation Laboratories at the Lautenberg Center for Immunology and Cancer Research, Institute for Medical Research Israel Canada, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
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2
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Choudhury SR, Babes L, Rahn JJ, Ahn BY, Goring KAR, King JC, Lau A, Petri B, Hao X, Chojnacki AK, Thanabalasuriar A, McAvoy EF, Tabariès S, Schraeder C, Patel KD, Siegel PM, Kopciuk KA, Schriemer DC, Muruve DA, Kelly MM, Yipp BG, Kubes P, Robbins SM, Senger DL. Dipeptidase-1 Is an Adhesion Receptor for Neutrophil Recruitment in Lungs and Liver. Cell 2020; 178:1205-1221.e17. [PMID: 31442408 DOI: 10.1016/j.cell.2019.07.017] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 05/14/2019] [Accepted: 07/11/2019] [Indexed: 12/22/2022]
Abstract
A hallmark feature of inflammation is the orchestrated recruitment of neutrophils from the bloodstream into inflamed tissue. Although selectins and integrins mediate recruitment in many tissues, they have a minimal role in the lungs and liver. Exploiting an unbiased in vivo functional screen, we identified a lung and liver homing peptide that functionally abrogates neutrophil recruitment to these organs. Using biochemical, genetic, and confocal intravital imaging approaches, we identified dipeptidase-1 (DPEP1) as the target and established its role as a physical adhesion receptor for neutrophil sequestration independent of its enzymatic activity. Importantly, genetic ablation or functional peptide blocking of DPEP1 significantly reduced neutrophil recruitment to the lungs and liver and provided improved survival in models of endotoxemia. Our data establish DPEP1 as a major adhesion receptor on the lung and liver endothelium and identify a therapeutic target for neutrophil-driven inflammatory diseases of the lungs.
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Affiliation(s)
- Saurav Roy Choudhury
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Liane Babes
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jennifer J Rahn
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Bo-Young Ahn
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Kimberly-Ann R Goring
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jennifer C King
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Arthur Lau
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Björn Petri
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Snyder Institute for Chronic Diseases Mouse Phenomics Resource Laboratory, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Xiaoguang Hao
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Andrew K Chojnacki
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Ajitha Thanabalasuriar
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Erin F McAvoy
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Sébastien Tabariès
- Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Christoph Schraeder
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Kamala D Patel
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Peter M Siegel
- Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Karen A Kopciuk
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Oncology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, AB T2S 3C3, Canada
| | - David C Schriemer
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Daniel A Muruve
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Margaret M Kelly
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Pathology and Laboratory Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Bryan G Yipp
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Critical Care Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Paul Kubes
- Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Stephen M Robbins
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Oncology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Donna L Senger
- Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Oncology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
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Kim HJ, Roh IS, Park HC, Ahn SB, Suh TY, Park KJ, Kang HE, Sohn HJ. Establishment of a Madin-Darby bovine kidney cell line expressing anchorless bovine prion protein. J Vet Med Sci 2018; 80:909-912. [PMID: 29618668 PMCID: PMC6021889 DOI: 10.1292/jvms.17-0521] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Enzyme-linked immunosorbent assay (ELISA) performed using extensively purified
bacterially expressed bovine prion protein (PrP) shows decreased cross-reactivity. We
generated a transduced Madin–Darby bovine kidney (MDBK) cell line continuously expressing
glycosylphosphatidylinositol (GPI)-anchorless bovine PrP (designated as MDBK ∆GPI protein)
by using a lentiviral expression system. The present study also described the method for
purifying bovine PrP through sequential culturing without the need for complex
purification protocol. Our results showed that the purified bovine PrP could be used as an
immunogen for developing anti-PrP monoclonal antibodies. Together, our results suggest
that the new GPI-anchorless bovine PrP and its purification method can be used for
performing basic studies for employing a cell-based approach.
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Affiliation(s)
- Hyo-Jin Kim
- OIE Reference Laboratory for CWD, Foreign Animal Disease Research Division, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbukdo 39660, Korea
| | - In-Soon Roh
- OIE Reference Laboratory for CWD, Foreign Animal Disease Research Division, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbukdo 39660, Korea
| | - Hoo-Chang Park
- OIE Reference Laboratory for CWD, Foreign Animal Disease Research Division, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbukdo 39660, Korea
| | - Su Bi Ahn
- OIE Reference Laboratory for CWD, Foreign Animal Disease Research Division, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbukdo 39660, Korea
| | - Tae-Young Suh
- OIE Reference Laboratory for CWD, Foreign Animal Disease Research Division, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbukdo 39660, Korea
| | - Kyung-Je Park
- OIE Reference Laboratory for CWD, Foreign Animal Disease Research Division, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbukdo 39660, Korea
| | - Hae-Eun Kang
- OIE Reference Laboratory for CWD, Foreign Animal Disease Research Division, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbukdo 39660, Korea
| | - Hyun-Joo Sohn
- OIE Reference Laboratory for CWD, Foreign Animal Disease Research Division, Animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbukdo 39660, Korea
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Chasen NM, Asady B, Lemgruber L, Vommaro RC, Kissinger JC, Coppens I, Moreno SNJ. A Glycosylphosphatidylinositol-Anchored Carbonic Anhydrase-Related Protein of Toxoplasma gondii Is Important for Rhoptry Biogenesis and Virulence. mSphere 2017; 2:e00027-17. [PMID: 28529974 PMCID: PMC5437132 DOI: 10.1128/msphere.00027-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/19/2017] [Indexed: 01/06/2023] Open
Abstract
Carbonic anhydrase-related proteins (CARPs) have previously been described as catalytically inactive proteins closely related to α-carbonic anhydrases (α-CAs). These CARPs are found in animals (both vertebrates and invertebrates) and viruses as either independent proteins or domains of other proteins. We report here the identification of a new CARP (TgCA_RP) in the unicellular organism Toxoplasma gondii that is related to the recently described η-class CA found in Plasmodium falciparum. TgCA_RP is posttranslationally modified at its C terminus with a glycosylphosphatidylinositol anchor that is important for its localization in intracellular tachyzoites. The protein localizes throughout the rhoptry bulbs of mature tachyzoites and to the outer membrane of nascent rhoptries in dividing tachyzoites, as demonstrated by immunofluorescence and immunoelectron microscopy using specific antibodies. T. gondii mutant tachyzoites lacking TgCA_RP display a growth and invasion phenotype in vitro and have atypical rhoptry morphology. The mutants also exhibit reduced virulence in a mouse model. Our results show that TgCA_RP plays an important role in the biogenesis of rhoptries. IMPORTANCEToxoplasma gondii is an intracellular pathogen that infects humans and animals. The pathogenesis of T. gondii is linked to its lytic cycle, which starts when tachyzoites invade host cells and secrete proteins from specialized organelles. Once inside the host cell, the parasite creates a parasitophorous vacuole (PV) where it divides. Rhoptries are specialized secretory organelles that contain proteins, many of which are secreted during invasion. These proteins have important roles not only during the initial interaction between parasite and host but also in the formation of the PV and in the modification of the host cell. We report here the identification of a new T. gondii carbonic anhydrase-related protein (TgCA_RP), which localizes to rhoptries of mature tachyzoites. TgCA_RP is important for the morphology of rhoptries and for invasion and growth of parasites. TgCA_RP is also critical for parasite virulence. We propose that TgCA_RP plays a role in the biogenesis of rhoptries.
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Affiliation(s)
- Nathan M. Chasen
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Beejan Asady
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Leandro Lemgruber
- Instituto Nacional de Metrologia, Inmetro-RJ, UFRJ, Rio de Janeiro, Brazil
| | | | - Jessica C. Kissinger
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
- Department of Genetics, University of Georgia, Athens, Georgia, USA
- Institute of Bioinformatics, University of Georgia, Athens, Georgia, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Silvia N. J. Moreno
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
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5
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Le Parc A, Honvo Houéto E, Pigat N, Chat S, Leonil J, Chanat E. The membrane-associated form of α(s1)-casein interacts with cholesterol-rich detergent-resistant microdomains. PLoS One 2014; 9:e115903. [PMID: 25549363 PMCID: PMC4280128 DOI: 10.1371/journal.pone.0115903] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 12/02/2014] [Indexed: 12/19/2022] Open
Abstract
Caseins, the main milk proteins, interact with colloidal calcium phosphate to form the casein micelle. The mesostructure of this supramolecular assembly markedly influences its nutritional and technological functionalities. However, its detailed molecular organization and the cellular mechanisms involved in its biogenesis have been only partially established. There is a growing body of evidence to support the concept that α(s1)-casein takes center stage in casein micelle building and transport in the secretory pathway of mammary epithelial cells. Here we have investigated the membrane-associated form of α(s1)-casein in rat mammary epithelial cells. Using metabolic labelling we show that α(s1)-casein becomes associated with membranes at the level of the endoplasmic reticulum, with no subsequent increase at the level of the Golgi apparatus. From morphological and biochemical data, it appears that caseins are in a tight relationship with membranes throughout the secretory pathway. On the other hand, we have observed that the membrane-associated form of α(s1)-casein co-purified with detergent-resistant membranes. It was poorly solubilised by Tween 20, partially insoluble in Lubrol WX, and substantially insoluble in Triton X-100. Finally, we found that cholesterol depletion results in the release of the membrane-associated form of α(s1)-casein. These experiments reveal that the insolubility of α(s1)-casein reflects its partial association with a cholesterol-rich detergent-resistant microdomain. We propose that the membrane-associated form of α(s1)-casein interacts with the lipid microdomain, or lipid raft, that forms within the membranes of the endoplasmic reticulum, for efficient forward transport and sorting in the secretory pathway of mammary epithelial cells.
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Affiliation(s)
- Annabelle Le Parc
- UR1196 Génomique et Physiologie de la Lactation, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
| | - Edith Honvo Houéto
- UR1196 Génomique et Physiologie de la Lactation, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
| | - Natascha Pigat
- UR1196 Génomique et Physiologie de la Lactation, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
| | - Sophie Chat
- UR1196 Génomique et Physiologie de la Lactation, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
| | - Joëlle Leonil
- UMR1253 Science et Technologie du Lait et de l'Œuf, Institut National de la Recherche Agronomique, Rennes, France
| | - Eric Chanat
- UR1196 Génomique et Physiologie de la Lactation, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
- * E-mail:
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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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Anti-tetherin activities of HIV-1 Vpu and Ebola virus glycoprotein do not involve removal of tetherin from lipid rafts. J Virol 2012; 86:5467-80. [PMID: 22398279 DOI: 10.1128/jvi.06280-11] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BST-2/tetherin is an interferon-inducible host restriction factor that blocks the release of newly formed enveloped viruses. It is enriched in lipid raft membrane microdomains, which are also the sites of assembly of several enveloped viruses. Viral anti-tetherin factors, such as the HIV-1 Vpu protein, typically act by removing tetherin from the cell surface. In contrast, the Ebola virus glycoprotein (GP) is unusual in that it blocks tetherin restriction without apparently altering its cell surface localization. We explored the possibility that GP acts to exclude tetherin from the specific sites of virus assembly without overtly removing it from the cell surface and that lipid raft exclusion is the mechanism involved. However, we found that neither GP nor Vpu had any effect on tetherin's distribution within lipid raft domains. Furthermore, GP did not prevent the colocalization of tetherin and budding viral particles. Contrary to previous reports, we also found no evidence that GP is itself a raft protein. Together, our data indicate that the exclusion of tetherin from lipid rafts is not the mechanism used by either HIV-1 Vpu or Ebola virus GP to counteract tetherin restriction.
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9
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Abstract
Infection by prions involves conversion of a host-encoded cell surface protein (PrP(C)) to a disease-related isoform (PrP(Sc)). PrP(C) carries two glycosylation sites variably occupied by complex N-glycans, which have been suggested by previous studies to influence the susceptibility to these diseases and to determine characteristics of prion strains. We used the Rov cell system, which is susceptible to sheep prions, to generate a series of PrP(C) glycosylation mutants with mutations at one or both attachment sites. We examined their subcellular trafficking and ability to convert into PrP(Sc) and to sustain stable prion propagation in the absence of wild-type PrP. The susceptibility to infection of mutants monoglycosylated at either site differed dramatically depending on the amino acid substitution. Aglycosylated double mutants showed overaccumulation in the Golgi compartment and failed to be infected. Introduction of an ectopic glycosylation site near the N terminus fully restored cell surface expression of PrP but not convertibility into PrP(Sc), while PrP(C) with three glycosylation sites conferred cell permissiveness to infection similarly to the wild type. In contrast, predominantly aglycosylated molecules with nonmutated N-glycosylation sequons, produced in cells expressing glycosylphosphatidylinositol-anchorless PrP(C), were able to form infectious PrP(Sc). Together our findings suggest that glycosylation is important for efficient trafficking of anchored PrP to the cell surface and sustained prion propagation. However, properly trafficked glycosylation mutants were not necessarily prone to conversion, thus making it difficult in such studies to discern whether the amino acid changes or glycan chain removal most influences the permissiveness to prion infection.
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Lee SH, Yu SY, Nakayama J, Khoo KH, Stone EL, Fukuda MN, Marth JD, Fukuda M. Core2 O-glycan structure is essential for the cell surface expression of sucrase isomaltase and dipeptidyl peptidase-IV during intestinal cell differentiation. J Biol Chem 2010; 285:37683-92. [PMID: 20841351 DOI: 10.1074/jbc.m110.162735] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Alterations in glycosylation play an important role during intestinal cell differentiation. Here, we compared expression of mucin-type O-glycan synthases from proliferating and differentiated HT-29 and Caco-2 cells. Mucin-type O-glycan structures were analyzed at both stages by mass spectrometry. Core2 β1,6-N-acetylglucosaminyltransferase-2 (C2GnT-2) was markedly increased in differentiated HT-29 and Caco-2 cells, but the core3 structure was hardly detectable. To determine whether such differential expression of mucin-type O-glycan structures has physiological significance in intestinal cell differentiation, expression of sucrase isomaltase (SI) and dipeptidyl-peptidase IV (DPP-IV), two well known intestinal differentiation markers, was examined. Interestingly, the fully glycosylated mature form of SI was decreased in C2GnT-2 knock-out mice but not in core2 N-acetylglucosaminyltransferase-3 (C2GnT-3) nulls. In addition, expression of SI and DPP-IV was dramatically reduced in C2GnT-1-3 triple knock-out mice. These patterns were confirmed by RNAi analysis; C2GnT-2 knockdown significantly reduced cell surface expression of SI and DPP-IV in Caco-2 cells. Similarly, overexpression of the core3 structure in HT-29 cells attenuated cell surface expression of both enzymes. These findings indicate that core3 O-glycan structure regulates cell surface expression of SI and DPP-IV and that core2 O-glycan is presumably an essential mucin-type O-glycan structure found in both molecules in vivo. Finally, goblet cells in the upper part of the crypt showed impaired maturation in the core2 O-glycan-deficient mice. These studies are the first to clearly identify functional mucin-type O-glycan structures modulating cell surface expression of SI and DPP-IV during the intestinal cell differentiation.
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Affiliation(s)
- Seung Ho Lee
- Glycobiology Unit, Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA
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11
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Domains in biological membranes. Exp Cell Res 2009; 315:2871-8. [PMID: 19632223 DOI: 10.1016/j.yexcr.2009.07.020] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/16/2009] [Accepted: 07/18/2009] [Indexed: 12/31/2022]
Abstract
Our current view on biological membranes has gradually evolved from the influential fluid mosaic model of the early 1970s to a distinctively more complex picture. Biological membranes are now assumed to encompass multiple membrane domains and a plethora of protein-lipid and protein-protein interactions that compartmentalize and temporarily order what has originally been envisioned to be mostly random. In this minireview, we will first highlight some structural principles that govern membrane domain formation and permit a classification of membrane domains. We will then focus on the still controversial issue of lipid-based membrane domains, or lipid rafts, and discuss recent advances in detecting these enigmatic structures in living cells. Finally we will evaluate biochemical approaches to characterize lipid rafts and discuss their contribution to the emerging topic of lipid raft diversity.
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12
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Fujiwara M, Hamada S, Hiratsuka M, Fukao Y, Kawasaki T, Shimamoto K. Proteome analysis of detergent-resistant membranes (DRMs) associated with OsRac1-mediated innate immunity in rice. PLANT & CELL PHYSIOLOGY 2009; 50:1191-200. [PMID: 19502382 PMCID: PMC2709549 DOI: 10.1093/pcp/pcp077] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 05/29/2009] [Indexed: 05/18/2023]
Abstract
OsRac1, a member of the Rac/Rop GTPase family, plays important roles as a molecular switch in rice innate immunity, and the active form of OsRac1 functions in the plasma membrane (PM). To study the precise localization of OsRac1 in the PM and its possible association with other signaling components, we performed proteomic analysis of DRMs (detergent-resistant membranes) isolated from rice suspension-cultured cells transformed with myc-tagged constitutively active (CA) OsRac1. DRMs are regions of the PM that are insoluble after Triton X-100 treatment under cold conditions and are thought to be involved in various signaling processes in animal, yeast and plant cells. We identified 192 proteins in DRMs that included receptor-like kinases (RLKs) such as Xa21, nucleotide-binding leucine-rich repeat (NB-LRR)-type disease resistance proteins, a glycosylphosphatidylinositol (GPI)-anchored protein, syntaxin, NADPH oxidase, a WD-40 repeat family protein and various GTP-binding proteins. Many of these proteins have been previously identified in the DRMs isolated from other plant species, and animal and yeast cells, validating the methods used in our study. To examine the possible association of DRMs and OsRac1-mediated innate immunity, we used rice suspension-cultured cells transformed with myc-tagged wild-type (WT) OsRac1 and found that OsRac1 and RACK1A, an effector of OsRac1, shifted to the DRMs after chitin elicitor treatment. These results suggest that OsRac1-mediated innate immunity is associated with DRMs in the PM.
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Affiliation(s)
- Masayuki Fujiwara
- Laboratory of Plant Protein Analysis, Plant Education Unit, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0192 Japan
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0192 Japan
| | - Satoshi Hamada
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0192 Japan
| | - Minori Hiratsuka
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0192 Japan
| | - Yoichiro Fukao
- Laboratory of Plant Protein Analysis, Plant Education Unit, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0192 Japan
| | - Tsutomu Kawasaki
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0192 Japan
| | - Ko Shimamoto
- Laboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, 630-0192 Japan
- *Corresponding author: E-mail, ; Fax: +81-743-72-5502
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Wetzel G, Heine M, Rohwedder A, Naim HY. Impact of glycosylation and detergent-resistant membranes on the function of intestinal sucrase-isomaltase. Biol Chem 2009; 390:545-9. [DOI: 10.1515/bc.2009.077] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Sucrase-isomaltase (SI) is a highly N- and O-glycosylated intestinal brush border membrane protein. SI is sorted with high fidelity to the apical membrane via O-linked glycans that mediate its association with lipid rafts or detergent-resistant membranes (DRMs). Here, we show that N- and O-glycosylation and DRMs are implicated in the regulation of the function of SI in intestinal Caco-2 cells. The activities of sucrase (SUC) and isomaltase (IM) increase substantially in DRMs when N- and O-glycosylation patterns are intact. Disruption of DRMs by solubilization with Triton X-100 at 37°C substantially reduces the activities of SUC and IM. Furthermore, modulation of O-glycosylation by benzyl-2-acetamido-2-deoxy-α-d-galactopyranoside and N-glycosylation by deoxymannojirimycin is linked to a decreased capacity of SI to associate with DRMs, with a subsequent reduction of the enzymatic activities of SUC and IM. This is the first report that reveals a direct role of N- and O-glycans in association with DRMs in regulating the function of a membrane glycoprotein.
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