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Bridges RJ, Bradbury NA. Cystic Fibrosis, Cystic Fibrosis Transmembrane Conductance Regulator and Drugs: Insights from Cellular Trafficking. Handb Exp Pharmacol 2018; 245:385-425. [PMID: 29460152 DOI: 10.1007/164_2018_103] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The eukaryotic cell is organized into membrane-delineated compartments that are characterized by specific cadres of proteins sustaining biochemically distinct cellular processes. The appropriate subcellular localization of proteins is key to proper organelle function and provides a physiological context for cellular processes. Disruption of normal trafficking pathways for proteins is seen in several genetic diseases, where a protein's absence for a specific subcellular compartment leads to organelle disruption, and in the context of an individual, a disruption of normal physiology. Importantly, several drug therapies can also alter protein trafficking, causing unwanted side effects. Thus, a deeper understanding of trafficking pathways needs to be appreciated as novel therapeutic modalities are proposed. Despite the promising efficacy of novel therapeutic agents, the intracellular bioavailability of these compounds has proved to be a potential barrier, leading to failures in treatments for various diseases and disorders. While endocytosis of drug moieties provides an efficient means of getting material into cells, the subsequent release and endosomal escape of materials into the cytosol where they need to act has been a barrier. An understanding of cellular protein/lipid trafficking pathways has opened up strategies for increasing drug bioavailability. Approaches to enhance endosomal exit have greatly increased the cytosolic bioavailability of drugs and will provide a means of investigating previous drugs that may have been shelved due to their low cytosolic concentration.
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Affiliation(s)
- Robert J Bridges
- Department of Physiology and Biophysics, Chicago Medical School, North Chicago, IL, USA
| | - Neil A Bradbury
- Department of Physiology and Biophysics, Chicago Medical School, North Chicago, IL, USA.
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2
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Windheim M, Höning S, Leppard KN, Butler L, Seed C, Ponnambalam S, Burgert HG. Sorting Motifs in the Cytoplasmic Tail of the Immunomodulatory E3/49K Protein of Species D Adenoviruses Modulate Cell Surface Expression and Ectodomain Shedding. J Biol Chem 2016; 291:6796-812. [PMID: 26841862 DOI: 10.1074/jbc.m115.684787] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Indexed: 11/06/2022] Open
Abstract
The E3 transcription unit of human species C adenoviruses (Ads) encodes immunomodulatory proteins that mediate direct protection of infected cells. Recently, we described a novel immunomodulatory function for E3/49K, an E3 protein uniquely expressed by species D Ads. E3/49K of Ad19a/Ad64, a serotype that causes epidemic keratokonjunctivitis, is synthesized as a highly glycosylated type I transmembrane protein that is subsequently cleaved, resulting in secretion of its large ectodomain (sec49K). sec49K binds to CD45 on leukocytes, impairing activation and functions of natural killer cells and T cells. E3/49K is localized in the Golgi/trans-Golgi network (TGN), in the early endosomes, and on the plasma membrane, yet the cellular compartment where E3/49K is cleaved and the protease involved remained elusive. Here we show that TGN-localized E3/49K comprises both newly synthesized and recycled molecules. Full-length E3/49K was not detected in late endosomes/lysosomes, but the C-terminal fragment accumulated in this compartment at late times of infection. Inhibitor studies showed that cleavage occurs in a post-TGN compartment and that lysosomotropic agents enhance secretion. Interestingly, the cytoplasmic tail of E3/49K contains two potential sorting motifs, YXXΦ (where Φ represents a bulky hydrophobic amino acid) and LL, that are important for binding the clathrin adaptor proteins AP-1 and AP-2in vitro Surprisingly, mutating the LL motif, either alone or together with YXXΦ, did not prevent proteolytic processing but increased cell surface expression and secretion. Upon brefeldin A treatment, cell surface expression was rapidly lost, even for mutants lacking all known endocytosis motifs. Together with immunofluorescence data, we propose a model for intracellular E3/49K transport whereby cleavage takes place on the cell surface by matrix metalloproteases.
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Affiliation(s)
- Mark Windheim
- From the School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom, the Institute of Biochemistry, Hannover Medical School, 30625 Hannover, Germany
| | - Stefan Höning
- the Institute for Biochemistry I and Center for Molecular Medicine Cologne, 50931 Cologne, Germany, and
| | - Keith N Leppard
- From the School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Larissa Butler
- From the School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Christina Seed
- From the School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Sreenivasan Ponnambalam
- the School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Hans-Gerhard Burgert
- From the School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom,
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3
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Stoops EH, Caplan MJ. Trafficking to the apical and basolateral membranes in polarized epithelial cells. J Am Soc Nephrol 2014; 25:1375-86. [PMID: 24652803 DOI: 10.1681/asn.2013080883] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Renal epithelial cells must maintain distinct protein compositions in their apical and basolateral membranes in order to perform their transport functions. The creation of these polarized protein distributions depends on sorting signals that designate the trafficking route and site of ultimate functional residence for each protein. Segregation of newly synthesized apical and basolateral proteins into distinct carrier vesicles can occur at the trans-Golgi network, recycling endosomes, or a growing assortment of stations along the cellular trafficking pathway. The nature of the specific sorting signal and the mechanism through which it is interpreted can influence the route a protein takes through the cell. Cell type-specific variations in the targeting motifs of a protein, as are evident for Na,K-ATPase, demonstrate a remarkable capacity to adapt sorting pathways to different developmental states or physiologic requirements. This review summarizes our current understanding of apical and basolateral trafficking routes in polarized epithelial cells.
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Affiliation(s)
- Emily H Stoops
- Departments of Cellular & Molecular Physiology and Cell Biology, Yale University School of Medicine, New Haven, Connecticut
| | - Michael J Caplan
- Departments of Cellular & Molecular Physiology and Cell Biology, Yale University School of Medicine, New Haven, Connecticut
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4
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van den Hoorn T, Paul P, Jongsma MLM, Neefjes J. Routes to manipulate MHC class II antigen presentation. Curr Opin Immunol 2010; 23:88-95. [PMID: 21112200 DOI: 10.1016/j.coi.2010.11.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 11/02/2010] [Indexed: 11/28/2022]
Abstract
MHC class II molecules (MHC-II) present antigenic fragments acquired in the endocytic route to the immune system for recognition and activation of CD4+ T cells. This ignites a series of immune responses. MHC-II strongly correlates to most autoimmune diseases. Understanding the biology of MHC-II is therefore expected to translate into novel means of autoimmunity control or immune response improvement. Although the basic cell biology of MHC-II antigen presentation is well understood, many novel aspects have been uncovered in recent years including means of antigen delivery, preparation for MHC-II loading, transport processes and vaccination strategies. We will discuss past, present and future of these insights into the biology of MHC-II.
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Affiliation(s)
- Tineke van den Hoorn
- Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, Netherlands
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5
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Tarragó-Trani MT, Storrie B. Alternate routes for drug delivery to the cell interior: pathways to the Golgi apparatus and endoplasmic reticulum. Adv Drug Deliv Rev 2007; 59:782-97. [PMID: 17669543 PMCID: PMC2134838 DOI: 10.1016/j.addr.2007.06.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Accepted: 06/12/2007] [Indexed: 11/29/2022]
Abstract
The targeted delivery of drugs to the cell interior can be accomplished by taking advantage of the various receptor-mediated endocytic pathways operating in a particular cell. Among these pathways, the retrograde trafficking pathway from endosomes to the Golgi apparatus, and endoplasmic reticulum is of special importance since it provides a route to deliver drugs bypassing the acid pH, hydrolytic environment of the lysosome. The existence of pathways for drug or antigen delivery to the endoplasmic reticulum and Golgi apparatus has been to a large extent an outcome of research on the trafficking of A/B type-bacterial or plant toxins such as Shiga toxin within the cell. The targeting properties of these toxins reside in their B subunit. In this article we present an overview of the multiplicity of pathways to deliver drugs intracellularly. We highlight the retrograde trafficking pathway illustrated by Shiga toxin and Shiga-like toxin, and the potential role of the B subunit of these toxins as carriers of drugs, antigens and imaging agents.
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Affiliation(s)
- Maria Teresa Tarragó-Trani
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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6
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Guezguez B, Vigneron P, Alais S, Jaffredo T, Gavard J, Mège RM, Dunon D. A dileucine motif targets MCAM-l cell adhesion molecule to the basolateral membrane in MDCK cells. FEBS Lett 2006; 580:3649-56. [PMID: 16756976 DOI: 10.1016/j.febslet.2006.05.048] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 05/17/2006] [Accepted: 05/18/2006] [Indexed: 01/28/2023]
Abstract
Melanoma cell adhesion molecule (MCAM), an adhesion molecule belonging to the Ig superfamily, is an endothelial marker and is expressed in different epithelia. MCAM is expressed as two isoforms differing by their cytoplasmic domain: MCAM-l and MCAM-s (long and short). In order to identify the respective role of each MCAM isoform, we analyzed MCAM isoform targeting in polarized epithelial Madin-Darby canine kidney (MDCK) cells using MCAM-GFP chimeras. Confocal microscopy revealed that MCAM-s and MCAM-l were addressed to the apical and basolateral membranes, respectively. Transfection of MCAM-l mutants established that a single dileucine motif (41-42) of the cytoplasmic domain was required for MCAM-l basolateral targeting in MDCK cells. Although double labelling experiments showed that MCAM-l is not a component of adherens junctions and focal adhesions, its expression on basolateral membranes suggests that MCAM-l is involved in epithelium insuring.
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Affiliation(s)
- Borhane Guezguez
- Université Pierre et Marie, Curie-Paris 6, CNRS UMR 7622, Bat C 6ème étage, Case 24, 9 quai Saint-Bernard, 75252 Paris Cedex 05, France
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7
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Doumanov JA, Daubrawa M, Unden H, Graeve L. Identification of a basolateral sorting signal within the cytoplasmic domain of the interleukin-6 signal transducer gp130. Cell Signal 2005; 18:1140-6. [PMID: 16274960 DOI: 10.1016/j.cellsig.2005.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Accepted: 09/09/2005] [Indexed: 01/30/2023]
Abstract
Interleukin-6-type cytokine receptors are expressed in polarized cells such as hepatocytes and intestinal cells. For the interleukin-6-receptor gp80 and its signal transducer gp130, a preferential basolateral localization was demonstrated in Madin-Darby canine kidney (MDCK) cells and two basolateral sorting signals were identified within the cytoplasmic domain of gp80. The cytoplasmic tail of gp130 is responsible for signaling via the Janus kinase/signal transducer and activator of transcription pathway. In addition, it mediates the internalization of the receptor complex which is dependent on a di-leucine motif. Truncated gp130 lacking the cytoplasmic domain is sorted apically in MDCK cells. For identification of the basolateral sorting signal(s) of gp130, a series of deletion mutants in the cytoplasmic domain of gp130 have been generated and stably expressed in MDCK cells. Biotinylation analyses of these mutants show that a ten amino acids sequence between amino acids 782 and 792 which contains the di-leucine internalization motif is also essential for a basolateral sorting. Accordingly, we detect apical delivery of a gp130 mutant in which the di-leucine motif has been exchanged by two alanines (gp130LL/AA). These findings indicate that the di-leucine motif which directs the internalization of the IL-6 receptor complex also mediates the basolateral sorting of the signal transducer gp130.
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Affiliation(s)
- Jordan A Doumanov
- Institut für Biologische Chemie und Ernährungswissenschaft, Universität Hohenheim, Garbenstr. 30, D-70599 Stuttgart, Germany
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8
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Newton EE, Wu Z, Simister NE. Characterization of basolateral-targeting signals in the neonatal Fc receptor. J Cell Sci 2005; 118:2461-9. [PMID: 15923659 DOI: 10.1242/jcs.02367] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The neonatal Fc receptor, FcRn, transports proteins through cells, avoiding degradative compartments. FcRn is used in many physiological processes where proteins must remain intact while they move through cells. These contexts include the transport of IgG antibodies from mother to offspring, and the protection of IgG and albumin from catabolism. In polarized cell models, FcRn in the plasma membrane is predominantly at the basolateral surface. This distribution depends on two signals that overlap endocytosis signals. One of these signals resembles a YXXPhi motif, but with a tryptophan in place of the critical tyrosine residue; the other is a DDXXXLL signal. We examined the effects of mutations in and around these signals on the basolateral targeting of rat FcRn in rat inner medullary collecting duct cells. We also studied a second acidic cluster, Glu331/Glu333, some distance from either endocytosis signal. Some amino acid substitutions in the W-2 and W+3 positions disrupted the tryptophan-based basolateral-targeting signal without impairing its function in endocytosis. The tryptophan-based basolateral targeting and endocytosis signals are thus distinct but overlapping, as has been seen for collinear tyrosine-based signals. Surprisingly, the tryptophan-based basolateral-targeting signal required the aspartate pair of the dileucine-based signal. This acidic cluster, separated by two amino acids from the Phi residue of the tryptophan signal, is therefore a component of both of the basolateral-targeting signals. The acidic cluster Glu-331/Glu333 was not required for basolateral targeting, but its replacement reduced endocytosis.
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Affiliation(s)
- Estelle E Newton
- Rosenstiel Center for Basic Biomedical Sciences and Biology Department, Brandeis University, Waltham, MA 02254-9110, USA
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9
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Mousavi SA, Malerød L, Berg T, Kjeken R. Clathrin-dependent endocytosis. Biochem J 2004; 377:1-16. [PMID: 14505490 PMCID: PMC1223844 DOI: 10.1042/bj20031000] [Citation(s) in RCA: 260] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2003] [Revised: 09/11/2003] [Accepted: 09/23/2003] [Indexed: 11/17/2022]
Abstract
The process by which clathrin-coated vesicles are produced involves interactions of multifunctional adaptor proteins with the plasma membrane, as well as with clathrin and several accessory proteins and phosphoinositides. Here we review recent findings highlighting new insights into mechanisms underlying clathrin-dependent endocytosis.
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Affiliation(s)
- Seyed Ali Mousavi
- Department of Biology, University of Oslo, P.O. Box 1050, Blindern, N-0316 Oslo, Norway
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10
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Nordeng TW, Gregers TF, Kongsvik TL, Méresse S, Gorvel JP, Jourdan F, Motta A, Bakke O. The cytoplasmic tail of invariant chain regulates endosome fusion and morphology. Mol Biol Cell 2002; 13:1846-56. [PMID: 12058053 PMCID: PMC117608 DOI: 10.1091/mbc.01-10-0478] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The major histocompatibility complex class II associated invariant chain (Ii) has been shown to inhibit endocytic transport and to increase the size of endosomes. We have recently found that this property has a significant impact on antigen processing and presentation. Here, we show in a cell-free endosome fusion assay that expression of Ii can increase fusion after phosphatidylinositol 3-kinase activity is blocked by wortmannin. In live cells wortmannin was also not able to block formation of the Ii-induced enlarged endosomes. The effects of Ii on endosomal transport and morphology depend on elements within the cytoplasmic tail. Data from mutagenesis analysis and nuclear magnetic resonance-based structure calculations of the Ii cytoplasmic tail demonstrate that free negative charges that are not involved in internal salt bridges are essential for both interactions between the tails and for the formation of enlarged endosomes. This correlation indicates that it is interactions between the Ii cytoplasmic tails that are involved in endosome fusion. The combined data from live cells, cell-free assays, and molecular dynamic simulations suggest that Ii molecules on different vesicles can promote endosome docking and fusion and thereby control endosomal traffic of membrane proteins and endosomal content.
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Affiliation(s)
- Tommy W Nordeng
- Centre d'Immunologie de Marseille-Luminy, Centre National de la Recherche Scientifique-INSERM-Univ-Med, 13288 Marseille, Cedex 09, France
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11
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Kongsvik TL, Höning S, Bakke O, Rodionov DG. Mechanism of interaction between leucine-based sorting signals from the invariant chain and clathrin-associated adaptor protein complexes AP1 and AP2. J Biol Chem 2002; 277:16484-8. [PMID: 11854303 DOI: 10.1074/jbc.m201583200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cytoplasmic tail of the invariant chain contains two leucine-based sorting signals, and each of those seems sufficient to route the invariant chain to its intracellular destination in either normal or polarized cells. It is believed that the intracellular routing of the invariant chain is mediated by its interactions with the clathrin-associated adaptor protein complexes AP1 and AP2. We () have previously demonstrated the in vitro interactions between the cytoplasmic tail of the invariant chain and AP1/AP2 complexes. These interactions were specific and depended on the critical leucine residues in the invariant chain's sorting signals. In the present study, we decided to investigate the molecular mechanism of these interactions. To this end, we constructed a set of glutathione S-transferase fusion proteins that contained the intact cytoplasmic tail of the invariant chain and its various mutants to define residues important for its interactions with AP1 and AP-2. Our results demonstrated the importance of several residues other than the critical leucine residues for such interactions. A strong correlation between in vitro binding of AP2 to the invariant chain and in vivo internalization of the invariant chain was observed, confirming the primary role of AP2 in recognition of endocytic signals. In addition, we demonstrated different requirements for AP1 and AP2 binding to cytoplasmic tail of the invariant chain, which may reflect that the different sorting pathways mediated by AP1 and AP2 involve their recognition of the primary structure of the sorting signal.
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Affiliation(s)
- Thomas L Kongsvik
- Division of Molecular Cell Biology, Department of Biology, University of Oslo, P. O. Box 1050 Blindern, N-0316 Oslo, Norway
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12
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Jablonka-Shariff A, Garcia-Campayo V, Boime I. Evolution of lutropin to chorionic gonadotropin generates a specific routing signal for apical release in vivo. J Biol Chem 2002; 277:879-82. [PMID: 11723109 DOI: 10.1074/jbc.c100402200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
One of the fundamental differences among mammals is the mechanism of maintaining the corpus luteum of pregnancy. Placentation in primates is associated with the production of the glycoprotein hormone chorionic gonadotropin (CG), which is secreted into the maternal serum and stimulates progesterone synthesis from the corpus luteum, which is essential for early development of the embryo. CG together with the pituitary hormones lutropin (LH), follitropin, and thyrotropin constitute the family of glycoprotein hormones comprised of a common alpha subunit and a hormone-specific beta subunit. The LHbeta and CGbeta subunits share 85% amino acid sequence identity, and functionally LH and CG are interchangeable. CGbeta evolved by a recent gene duplication event from the LHbeta locus, and despite the close relationship between them, their modes of secretion are quite different. CG release from the placenta is apically directed, whereas LH is released from the basal side of the cell, and the determinant(s) for this redirected trafficking are unknown. Here, using the polarized Madin-Darby canine kidney (MDCK) cell line, we provide evidence for the molecular basis of the different secretory patterns of LH and CG in vivo. The apical targeting of CG is programmed by a carboxyl-terminal sequence, which encodes a novel sorting signal. It is also apparent that the presence of the O-linked oligosaccharides in the CTP sequence contributes to this apical routing. The CTP, which is absent in LH, redirects CG to the maternal serum and permits the unique arrangement for primate placentation. Our data also show that the MDCK cells can distinguish the different secretory pathways for the gonadotropins and will be a valuable model for elucidating the determinants associated with the unique sorting of these functionally related hormones.
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Affiliation(s)
- Albina Jablonka-Shariff
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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13
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Miranda KC, Khromykh T, Christy P, Le TL, Gottardi CJ, Yap AS, Stow JL, Teasdale RD. A dileucine motif targets E-cadherin to the basolateral cell surface in Madin-Darby canine kidney and LLC-PK1 epithelial cells. J Biol Chem 2001; 276:22565-72. [PMID: 11312273 DOI: 10.1074/jbc.m101907200] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
E-cadherin is a major adherens junction protein of epithelial cells, with a central role in cell-cell adhesion and cell polarity. Newly synthesized E-cadherin is targeted to the basolateral cell surface. We analyzed targeting information in the cytoplasmic tail of E-cadherin by utilizing chimeras of E-cadherin fused to the ectodomain of the interleukin-2alpha (IL-2alpha) receptor expressed in Madin-Darby canine kidney and LLC-PK(1) epithelial cells. Chimeras containing the full-length or membrane-proximal half of the E-cadherin cytoplasmic tail were correctly targeted to the basolateral domain. Sequence analysis of the membrane-proximal tail region revealed the presence of a highly conserved dileucine motif, which was analyzed as a putative targeting signal by mutagenesis. Elimination of this motif resulted in the loss of Tac/E-cadherin basolateral localization, pinpointing this dileucine signal as being both necessary and sufficient for basolateral targeting of E-cadherin. Truncation mutants unable to bind beta-catenin were correctly targeted, showing, contrary to current understanding, that beta-catenin is not required for basolateral trafficking. Our results also provide evidence that dileucine-mediated targeting is maintained in LLC-PK(1) cells despite the altered polarity of basolateral proteins with tyrosine-based signals in this cell line. These results provide the first direct insights into how E-cadherin is targeted to the basolateral membrane.
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Affiliation(s)
- K C Miranda
- Institute for Molecular Bioscience, the Department of Biochemistry, and the Department of Physiology & Pharmacology, University of Queensland, Brisbane, Queensland 4072, Australia
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14
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Wehrle-Haller B, Imhof BA. Stem cell factor presentation to c-Kit. Identification of a basolateral targeting domain. J Biol Chem 2001; 276:12667-74. [PMID: 11152680 DOI: 10.1074/jbc.m008357200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stem cell factor (also known as mast cell growth factor and kit-ligand) is a transmembrane growth factor with a highly conserved cytoplasmic domain. Basolateral membrane expression in epithelia and persistent cell surface exposure of stem cell factor are required for complete biological activity in pigmentation, fertility, learning, and hematopoiesis. Here we show by site-directed mutagenesis that the cytoplasmic domain of stem cell factor contains a monomeric leucine-dependent basolateral targeting signal. N-terminal to this motif, a cluster of acidic amino acids serves to increase the efficiency of basolateral sorting mediated by the leucine residue. Hence, basolateral targeting of stem cell factor requires a mono-leucine determinant assisted by a cluster of acidic amino acids. This mono-leucine determinant is functionally conserved in colony-stimulating factor-1, a transmembrane growth factor related to stem cell factor. Furthermore, this leucine motif is not capable of inducing endocytosis, allowing for persistent cell surface expression of stem cell factor. In contrast, the mutated cytoplasmic tail found in the stem cell factor mutant Mgf(Sl17H) induces constitutive endocytosis by a motif that is related to signals for endocytosis and lysosomal targeting. Our findings therefore present mono-leucines as a novel type of protein sorting motif for transmembrane growth factors.
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Affiliation(s)
- B Wehrle-Haller
- Department of Pathology, Centre Medical Universitaire, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland.
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15
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Martens AS, Bode JG, Heinrich PC, Graeve L. The cytoplasmic domain of the interleukin-6 receptor gp80 mediates its basolateral sorting in polarized madin-darby canine kidney cells. J Cell Sci 2000; 113 ( Pt 20):3593-602. [PMID: 11017875 DOI: 10.1242/jcs.113.20.3593] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The IL-6 receptor complex is expressed in different polarized epithelial cells such as liver hepatocytes and intestinal cells. It consists of two subunits: gp80, which binds the ligand, and gp130, which is responsible for signal transduction. In stably transfected Madin-Darby canine kidney (MDCK) cells we have studied the localization of the human IL-6 receptor subunits and found that gp80 and gp130 are predominantly expressed at the basolateral membrane. Analysis of MDCK cells expressing truncated forms of gp80 or gp130 showed that loss of the cytoplasmic domains results in apical delivery. Expression of deletion mutants of gp80 in MDCK cells led to the identification of two discontinous motifs responsible for basolateral sorting: a membrane-proximal tyrosine-based motif (YSLG) and a more membrane-distal dileucine-type motif (LI). Activation of signal transducer and activator of transcription-3 (STAT-3) only occurred via basolaterally located gp80, suggesting that endogenous gp130 is also constrained to the basolateral plasma membrane. Our identification of a basolateral sorting signal within the cytoplasmic region of gp80 for the first time attributes a function to this domain.
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Affiliation(s)
- A S Martens
- Institute of Biochemistry, Universitätsklinikum der Rheinisch-Westfälischen Technischen Hochschule, Pauwelsstrasse 30, Germany.
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16
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Rodionov DG, Nordeng TW, Kongsvik TL, Bakke O. The cytoplasmic tail of CD1d contains two overlapping basolateral sorting signals. J Biol Chem 2000; 275:8279-82. [PMID: 10722655 DOI: 10.1074/jbc.275.12.8279] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CD1d is a member of the CD1 polypeptide family that represents a new arm of host defense against invading pathogens. In our previous work (Rodionov, D. G., Nordeng, T. W., Pedersen, K., Balk, S. P., and Bakke, O. (1999) J. Immunol. 162, 1488-1495) we have shown that CD1d contained a classic tyrosine-based internalization signal (YQGV) in its short cytoplasmic tail. CD1d is expressed in polarized epithelial cells, and we found that the cytoplasmic tail of CD1d also contained information for basolateral sorting. Interestingly, a mutation of the critical tyrosine residue of the endosomal sorting signal did not result in the loss of basolateral targeting of the mutant CD1d. To search for a basolateral sorting signal we have constructed a full set of alanine mutants, but no single alanine substitution inactivated the signal. However, deletions or mutations of either the C-terminal valine/leucine pair or the critical tyrosine residue from the internalization signal and either residue from the C-terminal valine/leucine pair inactivated basolateral sorting. Our data thus suggest that the cytoplasmic tail contains two overlapping basolateral signals, one tyrosine- and the other leucine-based, each being sufficient to direct CD1d to the basolateral membrane of polarized Madin-Darby canine kidney cells.
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Affiliation(s)
- D G Rodionov
- Division of Molecular Cell Biology, Department of Biology, University of Oslo, 0316 Oslo, Norway
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Hofmann MW, Höning S, Rodionov D, Dobberstein B, von Figura K, Bakke O. The leucine-based sorting motifs in the cytoplasmic domain of the invariant chain are recognized by the clathrin adaptors AP1 and AP2 and their medium chains. J Biol Chem 1999; 274:36153-8. [PMID: 10593899 DOI: 10.1074/jbc.274.51.36153] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Recognition of sorting signals within the cytoplasmic tail of membrane proteins by adaptor protein complexes is a crucial step in membrane protein sorting. The three known adaptor complexes, AP1, AP2, and AP3, have all been shown to recognize tyrosine- and leucine-based sorting signals, which are the most common sorting signals within membrane protein cytoplasmic tails. Although tyrosine-based signals are recognized by the micro-chains of adaptor complexes, the subunit recognizing leucine-based sorting signals is less clear. In this report we show by surface plasmon resonance that the two leucine-based sorting signals within the cytoplasmic tail of the invariant chain bind independently from each other to AP1 and AP2 but not to AP3. We also show that both motifs can be recognized by the micro-chains of AP1 and AP2. Moreover, by using monomeric as well as trimeric invariant chain constructs, we show that adaptor binding does not require trimerization of the invariant chain.
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Affiliation(s)
- M W Hofmann
- Center for Molecular Biology, University of Heidelberg, 69120 Heidelberg, Germany
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18
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Bakke O, Nordeng TW. Intracellular traffic to compartments for MHC class II peptide loading: signals for endosomal and polarized sorting. Immunol Rev 1999; 172:171-87. [PMID: 10631946 DOI: 10.1111/j.1600-065x.1999.tb01365.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In this review we focus on the traffic of MHC class II and endocytosed antigens to intracellular compartments where antigenic peptides are loaded. We also discuss briefly the nature of the peptide loading compartment and the sorting signals known to direct antigen receptors and MHC class II and associated molecules to this location. MHC class II molecules are expressed on a variety of polarized epithelial and endothelial cells, and polarized cells are thus potentially important for antigen presentation. Here we review some cell biological aspects of polarized sorting of MHC class II and the associated invariant chain and the signals that are involved in the sorting process to the basolateral domain. The molecules involved in sorting and loading of peptide may modulate antigen presentation, and in particular we discuss how invariant chain may change the cellular phenotype and the kinetics of the endosomal pathway.
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Affiliation(s)
- O Bakke
- Department of Biology, University of Oslo, Norway.
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19
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El Nemer W, Colin Y, Bauvy C, Codogno P, Fraser RH, Cartron JP, Le Van Kim CL. Isoforms of the Lutheran/basal cell adhesion molecule glycoprotein are differentially delivered in polarized epithelial cells. Mapping of the basolateral sorting signal to a cytoplasmic di-leucine motif. J Biol Chem 1999; 274:31903-8. [PMID: 10542217 DOI: 10.1074/jbc.274.45.31903] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lu and Lu(v13) are two glycoprotein (gp) isoforms that belong to the immunoglobulin superfamily and carry both the Lutheran (Lu) blood group antigens and the basal cell adhesion molecule epithelial cancer antigen. Lu (85 kDa) and Lu(v13) (78 kDa) gps, which differ only in the length of their cytoplasmic domain, are adhesion molecules that bind laminin. In nonerythroid tissues, the Lu/basal cell adhesion molecule antigens are predominantly expressed in the endothelium of blood vessel walls and in the basement membrane region of normal epithelial cells, whereas they exhibit a nonpolarized expression in some epithelial cancers. Here, we analyzed the polarization of Lu and Lu(v13) gps in epithelial cells by confocal microscopy and domain-selective biotinylation assays. Differentiated human colon carcinoma Caco-2 cells exhibited a polarized expression of endogenous Lu antigens associated with a predominant expression of the Lu isoform at the basolateral domain of the plasma membrane and a very low expression of the Lu(v13) isoform at both the apical and basolateral domains. Analysis of transfected Madin-Darby canine kidney cells revealed a basolateral expression of Lu gp and a nonpolarized expression of Lu(v13) gp. Delivery of Lu(v13) to both apical and basolateral surfaces showed similar kinetics, indicating that this isoform is directly transported to each surface domain. A dileucine motif at position 608-609, specific to the Lu isoform, was characterized as a dominant basolateral sorting signal that prevents Lu gp from taking the apical delivery pathway.
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Affiliation(s)
- W El Nemer
- INSERM U76, Institut National de la Transfusion Sanguine, 6 rue Alexandre Cabanel, 75015 Paris, France
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20
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Simonsen A, Pedersen KW, Nordeng TW, von der Lippe A, Stang E, Long EO, Bakke O. Polarized Transport of MHC Class II Molecules in Madin-Darby Canine Kidney Cells Is Directed by a Leucine-Based Signal in the Cytoplasmic Tail of the β-Chain. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.5.2540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
MHC class II molecules are found on the basolateral plasma membrane domain of polarized epithelial cells, where they can present Ag to intraepithelial lymphocytes in the vascular space. We have analyzed the sorting information required for efficient intracellular localization and polarized distribution of MHC class II molecules in stably transfected Madin-Darby canine kidney cells. These cells were able to present influenza virus particles to HLA-DR1-restricted T cell clones. Wild-type MHC class II molecules were located on the basolateral plasma membrane domain, in basolateral early endosomes, and in late multivesicular endosomes, the latter also containing the MHC class II-associated invariant chain and an HLA-DM fusion protein. A phenylalanine-leucine residue within the cytoplasmic tail of the β-chain was required for basolateral distribution, efficient internalization, and localization of the MHC class II molecules to basolateral early endosomes. However, distribution to apically located, late multivesicular endosomes did not depend on signals in the class II cytoplasmic tails as both wild-type class II molecules and mutant molecules lacking the phenylalanine-leucine motif were found in these compartments. Our results demonstrate that sorting information in the tails of class II dimers is an absolute requirement for their basolateral surface distribution and intracellular localization.
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Affiliation(s)
- Anne Simonsen
- *Department of Biology, University of Oslo, Oslo, Norway; and
| | | | | | | | - Espen Stang
- *Department of Biology, University of Oslo, Oslo, Norway; and
| | - Eric O. Long
- †Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852
| | - Oddmund Bakke
- *Department of Biology, University of Oslo, Oslo, Norway; and
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21
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Nordeng TW, Bakke O. Overexpression of proteins containing tyrosine- or leucine-based sorting signals affects transferrin receptor trafficking. J Biol Chem 1999; 274:21139-48. [PMID: 10409667 DOI: 10.1074/jbc.274.30.21139] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Targeting of many transmembrane proteins to post-Golgi compartments is dependent on cytoplasmically exposed sorting signals. The most widely used signals conform to the tyrosine- or the leucine-based motifs. Both types of signals have been implicated in protein localization to the same intracellular compartments, but previous results from both cell-free experiments and studies of transfected cell lines have indicated that the two types of signals interact with separate components of the sorting machinery. We have overexpressed several transmembrane proteins in stably transfected Madin-Darby canine kidney cells using an inducible promoter system. Overexpression of proteins containing tyrosine- or leucine-based sorting signals resulted in reduced internalization of the transferrin receptor, whereas recycling and polarized distribution was not influenced. Our results indicate that proteins with tyrosine- and leucine-based sorting signals can be transported along common saturable pathways.
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Affiliation(s)
- T W Nordeng
- Division of Molecular Cell Biology, Department of Biology, University of Oslo, Oslo 0316, Norway.
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22
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Kachinsky AM, Froehner SC, Milgram SL. A PDZ-containing scaffold related to the dystrophin complex at the basolateral membrane of epithelial cells. J Biophys Biochem Cytol 1999; 145:391-402. [PMID: 10209032 PMCID: PMC2133114 DOI: 10.1083/jcb.145.2.391] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Membrane scaffolding complexes are key features of many cell types, serving as specialized links between the extracellular matrix and the actin cytoskeleton. An important scaffold in skeletal muscle is the dystrophin-associated protein complex. One of the proteins bound directly to dystrophin is syntrophin, a modular protein comprised entirely of interaction motifs, including PDZ (protein domain named for PSD-95, discs large, ZO-1) and pleckstrin homology (PH) domains. In skeletal muscle, the syntrophin PDZ domain recruits sodium channels and signaling molecules, such as neuronal nitric oxide synthase, to the dystrophin complex. In epithelia, we identified a variation of the dystrophin complex, in which syntrophin, and the dystrophin homologues, utrophin and dystrobrevin, are restricted to the basolateral membrane. We used exogenously expressed green fluorescent protein (GFP)-tagged fusion proteins to determine which domains of syntrophin are responsible for its polarized localization. GFP-tagged full-length syntrophin targeted to the basolateral membrane, but individual domains remained in the cytoplasm. In contrast, the second PH domain tandemly linked to a highly conserved, COOH-terminal region was sufficient for basolateral membrane targeting and association with utrophin. The results suggest an interaction between syntrophin and utrophin that leaves the PDZ domain of syntrophin available to recruit additional proteins to the epithelial basolateral membrane. The assembly of multiprotein signaling complexes at sites of membrane specialization may be a widespread function of dystrophin-related protein complexes.
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Affiliation(s)
- A M Kachinsky
- Department of Cell and Molecular Physiology and Curriculum in Neurobiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7545, USA
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23
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Simmen T, Nobile M, Bonifacino JS, Hunziker W. Basolateral sorting of furin in MDCK cells requires a phenylalanine-isoleucine motif together with an acidic amino acid cluster. Mol Cell Biol 1999; 19:3136-44. [PMID: 10082580 PMCID: PMC84107 DOI: 10.1128/mcb.19.4.3136] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Furin is a subtilisin-related endoprotease which processes a wide range of bioactive proteins. Furin is concentrated in the trans-Golgi network (TGN), where proteolytic activation of many precursor proteins takes place. A significant fraction of furin, however, cycles among the TGN, the plasma membrane, and endosomes, indicating that the accumulation in the TGN reflects a dynamic localization process. The cytosolic domain of furin is necessary and sufficient for TGN localization, and two signals are responsible for retrieval of furin to the TGN. A tyrosine-based (YKGL) motif mediates internalization of furin from the cell surface into endosomes. An acidic cluster that is part of two casein kinase II phosphorylation sites (SDSEEDE) is then responsible for retrieval of furin from endosomes to the TGN. In addition, the acidic EEDE sequence also mediates endocytic activity. Here, we analyzed the sorting of furin in polarized epithelial cells. We show that furin is delivered to the basolateral surface of MDCK cells, from where a significant fraction of the protein can return to the TGN. A phenylalanine-isoleucine motif together with the acidic EEDE cluster is required for basolateral sorting and constitutes a novel signal regulating intracellular traffic of furin.
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Affiliation(s)
- T Simmen
- Institute of Biochemistry, BIL Biomedical Research Center, University of Lausanne, CH-1066 Epalinges, Switzerland
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