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Meabon JS, De Laat R, Ieguchi K, Wiley JC, Hudson MP, Bothwell M. LINGO-1 protein interacts with the p75 neurotrophin receptor in intracellular membrane compartments. J Biol Chem 2015; 290:9511-20. [PMID: 25666623 DOI: 10.1074/jbc.m114.608018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Indexed: 11/06/2022] Open
Abstract
Axon outgrowth inhibition in response to trauma is thought to be mediated via the binding of myelin-associated inhibitory factors (e.g. Nogo-66, myelin-associated glycoprotein, oligodendrocyte myelin glycoprotein, and myelin basic protein) to a putative tripartite LINGO-1·p75(NTR)·Nogo-66 receptor (NgR) complex at the cell surface. We found that endogenous LINGO-1 expression in neurons in the cortex and cerebellum is intracellular. Mutation or truncation of the highly conserved LINGO-1 C terminus altered this intracellular localization, causing poor intracellular retention and increased plasma membrane expression. p75(NTR) associated predominantly with natively expressed LINGO-1 containing immature N-glycans, characteristic of protein that has not completed trans-Golgi-mediated processing, whereas mutant forms of LINGO-1 with enhanced plasma membrane expression did not associate with p75(NTR). Co-immunoprecipitation experiments demonstrated that LINGO-1 and NgR competed for binding to p75(NTR) in a manner that is difficult to reconcile with the existence of a LINGO-1·p75(NTR)·NgR ternary complex. These findings contradict models postulating functional LINGO-1·p75(NTR)·NgR complexes in the plasma membrane.
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Affiliation(s)
- James S Meabon
- From the Departments of Psychiatry and Behavioral Sciences, the Mental Illness Research Education and Clinical Center, Veterans Affairs Medical Center, Seattle, Washington 98108
| | | | - Katsuaki Ieguchi
- the Department of Pharmacology, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | | | - Mark P Hudson
- Physiology and Biophysics, University of Washington, Seattle, Washington 98195
| | - Mark Bothwell
- Physiology and Biophysics, University of Washington, Seattle, Washington 98195,
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Driesbaugh KH, Buzza MS, Martin EW, Conway GD, Kao JPY, Antalis TM. Proteolytic activation of the protease-activated receptor (PAR)-2 by the glycosylphosphatidylinositol-anchored serine protease testisin. J Biol Chem 2014; 290:3529-41. [PMID: 25519908 DOI: 10.1074/jbc.m114.628560] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protease-activated receptors (PARs) are a family of seven-transmembrane, G-protein-coupled receptors that are activated by multiple serine proteases through specific N-terminal proteolytic cleavage and the unmasking of a tethered ligand. The majority of PAR-activating proteases described to date are soluble proteases that are active during injury, coagulation, and inflammation. Less investigation, however, has focused on the potential for membrane-anchored serine proteases to regulate PAR activation. Testisin is a unique trypsin-like serine protease that is tethered to the extracellular membrane of cells through a glycophosphatidylinositol (GPI) anchor. Here, we show that the N-terminal domain of PAR-2 is a substrate for testisin and that proteolytic cleavage of PAR-2 by recombinant testisin activates downstream signaling pathways, including intracellular Ca(2+) mobilization and ERK1/2 phosphorylation. When testisin and PAR-2 are co-expressed in HeLa cells, GPI-anchored testisin specifically releases the PAR-2 tethered ligand. Conversely, knockdown of endogenous testisin in NCI/ADR-Res ovarian tumor cells reduces PAR-2 N-terminal proteolytic cleavage. The cleavage of PAR-2 by testisin induces activation of the intracellular serum-response element and NFκB signaling pathways and the induction of IL-8 and IL-6 cytokine gene expression. Furthermore, the activation of PAR-2 by testisin results in the loss and internalization of PAR-2 from the cell surface. This study reveals a new biological substrate for testisin and is the first demonstration of the activation of a PAR by a serine protease GPI-linked to the cell surface.
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Affiliation(s)
- Kathryn H Driesbaugh
- From the Department of Physiology, Center for Vascular and Inflammatory Diseases, and
| | - Marguerite S Buzza
- From the Department of Physiology, Center for Vascular and Inflammatory Diseases, and
| | - Erik W Martin
- From the Department of Physiology, Center for Vascular and Inflammatory Diseases, and
| | - Gregory D Conway
- From the Department of Physiology, Center for Vascular and Inflammatory Diseases, and
| | - Joseph P Y Kao
- From the Department of Physiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Toni M Antalis
- From the Department of Physiology, Center for Vascular and Inflammatory Diseases, and
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Albersen M, Berkers J, Dekoninck P, Deprest J, Lue TF, Hedlund P, Lin CS, Bivalacqua TJ, Van Poppel H, De Ridder D, Van der Aa F. Expression of a Distinct Set of Chemokine Receptors in Adipose Tissue-Derived Stem Cells is Responsible for In Vitro Migration Toward Chemokines Appearing in the Major Pelvic Ganglion Following Cavernous Nerve Injury. Sex Med 2014; 1:3-15. [PMID: 25356281 PMCID: PMC4184711 DOI: 10.1002/sm2.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Adipose tissue-derived stem cells (ADSCs) herald tremendous promise for clinical application in a wide range of injuries and diseases. Several preclinical reports demonstrate their efficacy in the treatment of cavernous nerve (CN) injury-induced erectile dysfunction in rats. It was recently illustrated that these effects were established as a result of ADSC migration to the major pelvic ganglion (MPG) where these cells induced neuroregeneration in loco. AIMS The study aims to identify chemotactic factors in the MPG following injury and to match upregulated chemokines to their respective receptors in human ADSC on the genomic, structural, and functional levels. METHODS Quantitative real-time polymerase chain reaction, fluorescence-activated cell sorting (FACS), intracellular FACS, immunofluorescence microscopy, migration assays, and calcium imaging were used in this study. MAIN OUTCOME MEASURES The main outcomes are chemokine expression in the MPG following CN injury, and the functional and structural presence of chemokine receptors in ADSC. RESULTS CCR4, CX3CR1, and XCR1 are functionally and structurally present in human ADSC, and are activated by the chemokines CCL2, CX3CL1, and XCL1 respectively, which are upregulated in the MPG following CN injury. CXCR4 and its ligand CXCL12 (SDF1) are likely no major homing factors for ADSC. Expression of chemokine receptor mRNA in ADSC did not necessarily translate into receptor presence at the cell surface and/or functional activation of these receptors. Most of the expressed chemokine receptors were detected in the intracellular compartment of these cells. CONCLUSIONS We identified the ligand/chemokine receptor pairs CCL2/CCR4, CX3CL1/CX3CR1, and XCL1/XCR1 as potentially responsible for ADSC homing toward the MPG following CN injury. The intracellular localization of various chemokine receptors likely indicates redirecting of chemokine receptors to the cell surface under specific cellular conditions. Furthermore, modification of expression of these receptors at the genomic level may potentially lead to improved migration toward injury sites and thus enhancement of treatment efficacy. Albersen M, Berkers J, Dekoninck P, Deprest J, Lue TF, Hedlund P, Lin C-S, Bivalacqua TJ, Van Poppel H, De Ridder D, and Van der Aa F. Expression of a distinct set of chemokine receptors in adipose tissue-derived stem cells is responsible for in vitro migration toward chemokines appearing in the major pelvic ganglion following cavernous nerve injury. Sex Med 2013;1:3-15.
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Affiliation(s)
- Maarten Albersen
- Laboratory of Experimental Urology, Department of Development and Regeneration, University of Leuven Leuven, Belgium ; Laboratory of Experimental Gynecology, Department of Development and Regeneration, University of Leuven Leuven, Belgium
| | - Joost Berkers
- Laboratory of Experimental Urology, Department of Development and Regeneration, University of Leuven Leuven, Belgium
| | - Philip Dekoninck
- Laboratory of Experimental Gynecology, Department of Development and Regeneration, University of Leuven Leuven, Belgium
| | - Jan Deprest
- Laboratory of Experimental Gynecology, Department of Development and Regeneration, University of Leuven Leuven, Belgium
| | - Tom F Lue
- Knuppe Molecular Urology Laboratory, Department of Urology, University of California San Francisco, CA, USA
| | - Petter Hedlund
- Department of Urology, Urological Research Institute, Vita-Salute San Raffaele University Milan, Italy
| | - Ching-Shwun Lin
- Knuppe Molecular Urology Laboratory, Department of Urology, University of California San Francisco, CA, USA
| | - Trinity J Bivalacqua
- Department of Urology, The James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions Baltimore, MD, USA
| | - Hendrik Van Poppel
- Laboratory of Experimental Urology, Department of Development and Regeneration, University of Leuven Leuven, Belgium
| | - Dirk De Ridder
- Laboratory of Experimental Urology, Department of Development and Regeneration, University of Leuven Leuven, Belgium
| | - Frank Van der Aa
- Laboratory of Experimental Urology, Department of Development and Regeneration, University of Leuven Leuven, Belgium
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Lutz D, Loers G, Kleene R, Oezen I, Kataria H, Katagihallimath N, Braren I, Harauz G, Schachner M. Myelin basic protein cleaves cell adhesion molecule L1 and promotes neuritogenesis and cell survival. J Biol Chem 2014; 289:13503-18. [PMID: 24671420 DOI: 10.1074/jbc.m113.530238] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The cell adhesion molecule L1 is a Lewis(x)-carrying glycoprotein that plays important roles in the developing and adult nervous system. Here we show that myelin basic protein (MBP) binds to L1 in a Lewis(x)-dependent manner. Furthermore, we demonstrate that MBP is released by murine cerebellar neurons as a sumoylated dynamin-containing protein upon L1 stimulation and that this MBP cleaves L1 as a serine protease in the L1 extracellular domain at Arg(687) yielding a transmembrane fragment that promotes neurite outgrowth and neuronal survival in cell culture. L1-induced neurite outgrowth and neuronal survival are reduced in MBP-deficient cerebellar neurons and in wild-type cerebellar neurons in the presence of an MBP antibody or L1 peptide containing the MBP cleavage site. Genetic ablation of MBP in shiverer mice and mutagenesis of the proteolytically active site in MBP or of the MBP cleavage site within L1 as well as serine protease inhibitors and an L1 peptide containing the MBP cleavage site abolish generation of the L1 fragment. Our findings provide evidence for novel functions of MBP in the nervous system.
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Affiliation(s)
- David Lutz
- From the Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
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Maier PJ, Zemoura K, Acuña MA, Yévenes GE, Zeilhofer HU, Benke D. Ischemia-like oxygen and glucose deprivation mediates down-regulation of cell surface γ-aminobutyric acidB receptors via the endoplasmic reticulum (ER) stress-induced transcription factor CCAAT/enhancer-binding protein (C/EBP)-homologous protein (CHOP). J Biol Chem 2014; 289:12896-907. [PMID: 24668805 DOI: 10.1074/jbc.m114.550517] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cerebral ischemia frequently leads to long-term disability and death. Excitotoxicity is believed to be the main cause for ischemia-induced neuronal death. Although a role of glutamate receptors in this process has been firmly established, the contribution of metabotropic GABAB receptors, which control excitatory neurotransmission, is less clear. A prominent characteristic of ischemic insults is endoplasmic reticulum (ER) stress associated with the up-regulation of the transcription factor CCAAT/enhancer-binding protein-homologous protein (CHOP). After inducing ER stress in cultured cortical neurons by sustained Ca(2+) release from intracellular stores or by a brief episode of oxygen and glucose deprivation (in vitro model of cerebral ischemia), we observed an increased expression of CHOP accompanied by a strong reduction of cell surface GABAB receptors. Our results indicate that down-regulation of cell surface GABAB receptors is caused by the interaction of the receptors with CHOP in the ER. Binding of CHOP prevented heterodimerization of the receptor subunits GABAB1 and GABAB2 and subsequent forward trafficking of the receptors to the cell surface. The reduced level of cell surface receptors diminished GABAB receptor signaling and, thus, neuronal inhibition. These findings indicate that ischemia-mediated up-regulation of CHOP down-regulates cell surface GABAB receptors by preventing their trafficking from the ER to the plasma membrane. This mechanism leads to diminished neuronal inhibition and may contribute to excitotoxicity in cerebral ischemia.
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Affiliation(s)
- Patrick J Maier
- From the Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Lee MM, Nasirikenari M, Manhardt CT, Ashline DJ, Hanneman AJ, Reinhold VN, Lau JTY. Platelets support extracellular sialylation by supplying the sugar donor substrate. J Biol Chem 2014; 289:8742-8. [PMID: 24550397 DOI: 10.1074/jbc.c113.546713] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Sizable pools of freely circulating glycosyltransferases are in blood, but understanding their physiologic contributions has been hampered because functional sources of sugar donor substrates needed to drive extracellular glycosylation have not been identified. The blood-borne ST6Gal-1 produced and secreted by the liver is the most noted among the circulatory glycosyltransferases, and decorates marrow hematopoietic progenitor cells with α2,6-linked sialic acids and restricts blood cell production. Platelets, upon activation, secrete a plethora of bioactive molecules including pro- and anti-inflammatory mediators. Cargos of sugar donor substrates for glycosyltransferase activity have also been reported in platelets. Here, we implemented a cell-based system to interrogate platelets for their ability to deliver effectively the sugar donor substrate for extracellular ST6Gal-1 to function. We report that thrombin-activated platelets, at physiologic concentration and pH, can efficiently and effectively substitute for CMP-sialic acid in extracellular ST6Gal-1-mediated sialylation of target cell surfaces. Activated platelets can also supply the sialic acid donor to sialylate the synthetic acceptor, Gal(β1,4)GlcNAcα-o-benzyl, with the product Sia(α2,6)Gal(β1,4)GlcNAcα-o-benzyl structurally confirmed by LC/MS. Platelet-secreted donor substrate was recovered in the 100,000 × g sediment, strongly suggesting the association of this otherwise soluble substrate, putatively CMP-sialic acid, within platelet microparticles. Sequestration within microparticles may facilitate delivery of glycosylation substrate at effective dosages to sites of extracellular glycosylation while minimizing excessive dilution.
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Affiliation(s)
- Melissa M Lee
- From the Departments of Molecular and Cellular Biology, and
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Möller-Hackbarth K, Dewitz C, Schweigert O, Trad A, Garbers C, Rose-John S, Scheller J. A disintegrin and metalloprotease (ADAM) 10 and ADAM17 are major sheddases of T cell immunoglobulin and mucin domain 3 (Tim-3). J Biol Chem 2013; 288:34529-44. [PMID: 24121505 DOI: 10.1074/jbc.m113.488478] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
T cell immunoglobulin and mucin domain 3 (Tim-3) dampens the response of CD4(+) and CD8(+) effector T cells via induction of cell death and/or T cell exhaustion and enhances the ability of macrophages to clear pathogens via binding to galectin 9. Here we provide evidence that human Tim-3 is a target of A disintegrin and metalloprotease (ADAM)-mediated ectodomain shedding resulting in a soluble form of Tim-3. We identified ADAM10 and ADAM17 as major sheddases of Tim-3 as shown by ADAM-specific inhibitors and the ADAM10 pro-domain in HEK293 cells and ADAM10/ADAM17-deficient murine embryonic fibroblasts. PMA-induced shedding of Tim-3 was abrogated by deletion of amino acids Glu(181)-Asp(190) of the stalk region and Tim-3 lacking the intracellular domain was not efficiently cleaved after PMA stimulation. Surprisingly, a single lysine residue within the intracellular domain rescues shedding of Tim-3. Shedding of endogenous Tim-3 was found in primary human CD14(+) monocytes after PMA and ionomycin stimulation. Importantly, the recently described down-regulation of Tim-3 from Toll-like receptor-activated CD14(+) monocytes was caused by ADAM10- and ADAM17-mediated shedding. Inhibition of Tim-3 shedding from lipopolysaccharide-induced monocytes did not influence lipopolysaccharide-induced TNFα and IL-6 but increases IL-12 expression. In summary, we describe Tim-3 as novel target for ADAM-mediated ectodomain shedding and suggest a role of Tim-3 shedding in TLR-mediated immune responses of CD14(+) monocytes.
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Affiliation(s)
- Katja Möller-Hackbarth
- From the Institute of Biochemistry, Medical Faculty, Christian-Albrechts-University, 24098 Kiel, Germany and
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Abstract
Natalizumab antibody to α4-integrins is used in therapy of multiple sclerosis and Crohn's disease. A crystal structure of the Fab bound to an α4 integrin β-propeller and thigh domain fragment shows that natalizumab recognizes human-mouse differences on the circumference of the β-propeller domain. The epitope is adjacent to but outside of a ligand-binding groove formed at the interface with the β-subunit βI domain and shows no difference in structure when bound to Fab. Competition between Fab and the ligand vascular cell adhesion molecule (VCAM) for binding to cell surface α4β1 shows noncompetitive antagonism. In agreement, VCAM docking models suggest that binding of domain 1 of VCAM to α4-integrins is unimpeded by the Fab, and that bound Fab requires a change in orientation between domains 1 and 2 of VCAM for binding to α4β1. Mapping of species-specific differences onto α4β1 and α4β7 shows that their ligand-binding sites are highly conserved. Skewing away from these conserved regions of the epitopes recognized by current therapeutic function-blocking antibodies has resulted in previously unanticipated mechanisms of action.
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Affiliation(s)
- Yamei Yu
- From the Program in Cellular and Molecular Medicine, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
| | - Thomas Schürpf
- From the Program in Cellular and Molecular Medicine, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
| | - Timothy A Springer
- From the Program in Cellular and Molecular Medicine, Children's Hospital Boston and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115.
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Johnson TK, Brown LA, Denell RE. Changes in cell surface proteins of culturedDrosophila cells exposed to 20-hydroxyecdysone. ACTA ACUST UNITED AC 1983; 192:103-107. [PMID: 28305504 DOI: 10.1007/bf00848486] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/1982] [Accepted: 01/26/1983] [Indexed: 11/24/2022]
Abstract
Drosophila cell lines have provided popular material for study of the mechanisms by which steroid hormones regulate cellular events. Previous investigations at the organismic or organ level have suggested that ecdysteroids are bound by a cytoplasmic receptor, and that the resulting complex translocates to the nucleus where it results in active transcription of a few genes. The protein products of these primary responding genes then modulate a larger series of secondary transcriptional changes. In cultured cells, other investigators have detected the hormonally-induced synthesis of only 4-5 new polypeptides through 72 h of treatment. Although these proteins may represent the gene products associated with the primary response, this small number of changes is surprising in view of the rapid morphological alteration of the cells and changes in such surface-mediated behavior as substrate adhesion and agglutinability observed within the same time interval. In this report, we show that lactoperoxidase-catalyzed radioiodination followed by 2-dimensional polyacrylamide gel electrophoresis and autoradiography provide an effective protocol for visualizing cell surface proteins of a Drosophila cell line. Among the more than 175 labeled species detected, comparisons of control cells with those treated by 20-hydroxyecdysone for 72 h shows at least 27 differences. We interpret these differences as the result of the secondary transcriptional response to the hormone.
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Affiliation(s)
| | - Leslie Ann Brown
- Division of Biology, Kansas State University, 66506, Manhattan, KS, USA
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