1
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Vigano MA, Ell CM, Kustermann MMM, Aguilar G, Matsuda S, Zhao N, Stasevich TJ, Affolter M, Pyrowolakis G. Protein manipulation using single copies of short peptide tags in cultured cells and in Drosophila melanogaster. Development 2021; 148:dev191700. [PMID: 33593816 PMCID: PMC7990863 DOI: 10.1242/dev.191700] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 02/09/2021] [Indexed: 01/01/2023]
Abstract
Cellular development and function rely on highly dynamic molecular interactions among proteins distributed in all cell compartments. Analysis of these interactions has been one of the main topics in cellular and developmental research, and has been mostly achieved by the manipulation of proteins of interest (POIs) at the genetic level. Although genetic strategies have significantly contributed to our current understanding, targeting specific interactions of POIs in a time- and space-controlled manner or analysing the role of POIs in dynamic cellular processes, such as cell migration or cell division, would benefit from more-direct approaches. The recent development of specific protein binders, which can be expressed and function intracellularly, along with advancement in synthetic biology, have contributed to the creation of a new toolbox for direct protein manipulations. Here, we have selected a number of short-tag epitopes for which protein binders from different scaffolds have been generated and showed that single copies of these tags allowed efficient POI binding and manipulation in living cells. Using Drosophila, we also find that single short tags can be used for POI manipulation in vivo.
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Affiliation(s)
- M Alessandra Vigano
- Growth and Development, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Clara-Maria Ell
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany
- Institute for Biology I, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
- Center for Biological Systems Analysis, University of Freiburg, Habsburgerstrasse 49, 79104 Freiburg, Germany
| | - Manuela M M Kustermann
- Institute for Biology I, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
- Center for Biological Systems Analysis, University of Freiburg, Habsburgerstrasse 49, 79104 Freiburg, Germany
| | - Gustavo Aguilar
- Growth and Development, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Shinya Matsuda
- Growth and Development, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Ning Zhao
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Timothy J Stasevich
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Markus Affolter
- Growth and Development, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - George Pyrowolakis
- Institute for Biology I, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
- Center for Biological Systems Analysis, University of Freiburg, Habsburgerstrasse 49, 79104 Freiburg, Germany
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2
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Land MA, Chapman HL, Davis-Reyes BD, Felsing DE, Allen JA, Moeller FG, Elferink LA, Cunningham KA, Anastasio NC. Serotonin 5-HT 2C Receptor Cys23Ser Single Nucleotide Polymorphism Associates with Receptor Function and Localization In Vitro. Sci Rep 2019; 9:16737. [PMID: 31723224 PMCID: PMC6853916 DOI: 10.1038/s41598-019-53124-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 10/21/2019] [Indexed: 11/09/2022] Open
Abstract
A non-synonymous single nucleotide polymorphism of the human serotonin 5-HT2C receptor (5-HT2CR) gene that converts a cysteine to a serine at amino acid codon 23 (Cys23Ser) appears to impact 5-HT2CR pharmacology at a cellular and systems level. We hypothesized that the Cys23Ser alters 5-HT2CR intracellular signaling via changes in subcellular localization in vitro. Using cell lines stably expressing the wild-type Cys23 or the Ser23 variant, we show that 5-HT evokes intracellular calcium release with decreased potency and peak response in the Ser23 versus the Cys23 cell lines. Biochemical analyses demonstrated lower Ser23 5-HT2CR plasma membrane localization versus the Cys23 5-HT2CR. Subcellular localization studies demonstrated O-linked glycosylation of the Ser23 variant, but not the wild-type Cys23, may be a post-translational mechanism which alters its localization within the Golgi apparatus. Further, both the Cys23 and Ser23 5-HT2CR are present in the recycling pathway with the Ser23 variant having decreased colocalization with the early endosome versus the Cys23 allele. Agonism of the 5-HT2CR causes the Ser23 variant to exit the recycling pathway with no effect on the Cys23 allele. Taken together, the Ser23 variant exhibits a distinct pharmacological and subcellular localization profile versus the wild-type Cys23 allele, which could impact aspects of receptor pharmacology in individuals expressing the Cys23Ser SNP.
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Affiliation(s)
| | - Holly L Chapman
- Center for Addiction Research, Galveston, TX, USA.,Department of Pharmacology and Toxicology, Galveston, TX, USA
| | | | - Daniel E Felsing
- Center for Addiction Research, Galveston, TX, USA.,Department of Pharmacology and Toxicology, Galveston, TX, USA
| | - John A Allen
- Center for Addiction Research, Galveston, TX, USA.,Department of Pharmacology and Toxicology, Galveston, TX, USA
| | - F Gerard Moeller
- Center for Addiction Research, Galveston, TX, USA.,Department of Psychiatry, Virginia Commonwealth University, Richmond, VA, USA
| | - Lisa A Elferink
- Center for Addiction Research, Galveston, TX, USA.,Department of Neuroscience, Cell Biology and Anatomy, University of Texas Medical Branch, Galveston, TX, USA
| | - Kathryn A Cunningham
- Center for Addiction Research, Galveston, TX, USA.,Department of Pharmacology and Toxicology, Galveston, TX, USA
| | - Noelle C Anastasio
- Center for Addiction Research, Galveston, TX, USA. .,Department of Pharmacology and Toxicology, Galveston, TX, USA.
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3
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Briant K, Johnson N, Swanton E. Transmembrane domain quality control systems operate at the endoplasmic reticulum and Golgi apparatus. PLoS One 2017; 12:e0173924. [PMID: 28384259 PMCID: PMC5383021 DOI: 10.1371/journal.pone.0173924] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 02/28/2017] [Indexed: 01/14/2023] Open
Abstract
Multiple protein quality control systems operate to ensure that misfolded proteins are efficiently cleared from the cell. While quality control systems that assess the folding status of soluble domains have been extensively studied, transmembrane domain (TMD) quality control mechanisms are poorly understood. Here, we have used chimeras based on the type I plasma membrane protein CD8 in which the endogenous TMD was substituted with transmembrane sequences derived from different polytopic membrane proteins as a mode to investigate the quality control of unassembled TMDs along the secretory pathway. We find that the three TMDs examined prevent trafficking of CD8 to the cell surface via potentially distinct mechanisms. CD8 containing two distinct non-native transmembrane sequences escape the ER and are subsequently retrieved from the Golgi, possibly via Rer1, leading to ER localisation at steady state. A third chimera, containing an altered transmembrane domain, was predominantly localised to the Golgi at steady state, indicating the existence of an additional quality control checkpoint that identifies non-native transmembrane domains that have escaped ER retention and retrieval. Preliminary experiments indicate that protein retained by quality control mechanisms at the Golgi are targeted to lysosomes for degradation.
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Affiliation(s)
- Kit Briant
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Nicholas Johnson
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Eileithyia Swanton
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
- * E-mail:
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4
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Briant K, Koay YH, Otsuka Y, Swanton E. ERAD of proteins containing aberrant transmembrane domains requires ubiquitylation of cytoplasmic lysine residues. J Cell Sci 2015; 128:4112-25. [PMID: 26446255 PMCID: PMC4712780 DOI: 10.1242/jcs.171215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 09/28/2015] [Indexed: 11/29/2022] Open
Abstract
Clearance of misfolded proteins from the endoplasmic reticulum (ER) is mediated by the ubiquitin-proteasome system in a process known as ER-associated degradation (ERAD). The mechanisms through which proteins containing aberrant transmembrane domains are degraded by ERAD are poorly understood. To address this question, we generated model ERAD substrates based on CD8 with either a non-native transmembrane domain but a folded ER luminal domain (CD8TMD*), or the native transmembrane domain but a misfolded luminal domain (CD8LUM*). Although both chimeras were degraded by ERAD, we found that the location of the folding defect determined the initial site of ubiquitylation. Ubiquitylation of cytoplasmic lysine residues was required for the extraction of CD8TMD* from the ER membrane during ERAD, whereas CD8LUM* continued to be degraded in the absence of cytoplasmic lysine residues. Cytoplasmic lysine residues were also required for degradation of an additional ERAD substrate containing an unassembled transmembrane domain and when a non-native transmembrane domain was introduced into CD8LUM*. Our results suggest that proteins with defective transmembrane domains are removed from the ER through a specific ERAD mechanism that depends upon ubiquitylation of cytoplasmic lysine residues. Summary: Proteins containing defective transmembrane domains are removed from the endoplasmic reticulum through a specific mechanism that depends upon the ubiquitylation of cytoplasmic lysine residues.
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Affiliation(s)
- Kit Briant
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Yee-Hui Koay
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Yuka Otsuka
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Eileithyia Swanton
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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5
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D'Agostino M, Crespi A, Polishchuk E, Generoso S, Martire G, Colombo SF, Bonatti S. ER reorganization is remarkably induced in COS-7 cells accumulating transmembrane protein receptors not competent for export from the endoplasmic reticulum. J Membr Biol 2014; 247:1149-59. [PMID: 25086772 DOI: 10.1007/s00232-014-9710-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/15/2014] [Indexed: 10/24/2022]
Abstract
The newly synthesized mutant L501fsX533 Frizzled-4 form and the alpha3beta4 nicotinic acetylcholine receptor expressed in the absence of nicotine accumulate in the endoplasmic reticulum of COS-7 cells and induce the formation of large areas of smooth and highly convoluted cisternae. This results in a generalized block of the transport to the Golgi complex of newly synthesized proteins. Intriguingly, both effects happen peculiarly in COS-7 cells; HeLa, Huh-7, and HEK293 cells expressing the two receptors at similar level than COS-7 cells show normal ER and normal transport toward the plasma membrane. These results question the conclusion that a dominant-negative mechanism would explain the dominance of the mutant L501fsX533 Fz4 allele in the transmission of a form of Familial exudative vitreoretinopathy. Moreover, they indicate that the coordination of endoplasmic reticulum homeostasis in COS-7 cells is particularly error prone. This finding suggests that COS-7 cells may be extremely useful to study the molecular mechanisms regulating endoplasmic reticulum size and architecture.
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Affiliation(s)
- Massimo D'Agostino
- Department of Molecular medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
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6
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Andersen DC, Goochee CF. The effect of ammonia on the O-linked glycosylation of granulocyte colony-stimulating factor produced by chinese hamster ovary cells. Biotechnol Bioeng 2012; 47:96-105. [PMID: 18623371 DOI: 10.1002/bit.260470112] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Ammonium ion concentrations ranging from 0 to 10 mM are shown to significantly reduce the sialylation of granuiocyte colony-stimulating factor (G-CSF) produced by recombinant Chinese hamster ovary cells. Specifically, the degree of completion of the final reaction in the O-linked glycosylation pathway, the addition of sialic acid in an alpha(2,6) linkage to N-acetylgalactosamine, is reduced by NH(4) (+) concentrations of as low as 2 mM. The effect of ammonia on sialylation is rapid, sustained, and does not affect the secretion rate of G-CSF. Additionally, the effect can be mimicked using the weak base chloroquine, suggesting that the effect is related to the weak base characteristics of ammonia. In support of this hypothesis, experiments using brefeldin A suggest that the addition of sialic acid in an alpha(2,6) linkage to N-acetylgalactosamine occurs in the trans-Golgi compartment prior to the trans-Golgi network, which would be expected under normal conditions to have a slightly acidic pH in the range from 6.5 to 6.75. Ammonium ion concentrations of 10 mM would be expected to reduce significantly the differences in pH between acidic intracellular compartments and the cytoplasm. The pH-activity profile for the CHO O-linked alpha(2,6) sialytransferase using monosialylated G-CSF as a substrate reveals a twofold decrease in enzymatic activity across the pH range from 6.75 to 7.0.Mathematical modeling of this sialylation reaction supports the hypothesis that this twofold decrease in sialyltransferase activity resulting from an ammoniainduced increase in trans-Golgi pH could produce the observed decrease in G-CSF sialylation. (c) 1995 John Wiley & Sons, Inc.
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Affiliation(s)
- D C Andersen
- Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025
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7
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D'Agostino M, Tornillo G, Caporaso MG, Barone MV, Ghigo E, Bonatti S, Mottola G. Ligand of Numb proteins LNX1p80 and LNX2 interact with the human glycoprotein CD8α and promote its ubiquitylation and endocytosis. J Cell Sci 2011; 124:3545-56. [DOI: 10.1242/jcs.081224] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
E3 ubiquitin ligases give specificity to the ubiquitylation process by selectively binding substrates. Recently, their function has emerged as a crucial modulator of T-cell tolerance and immunity. However, substrates, partners and mechanism of action for most E3 ligases remain largely unknown. In this study, we identified the human T-cell co-receptor CD8 α-chain as binding partner of the ligand of Numb proteins X1 (LNX1p80 isoform) and X2 (LNX2). Both LNX mRNAs were found expressed in T cells purified from human blood, and both proteins interacted with CD8α in human HPB-ALL T cells. By using an in vitro assay and a heterologous expression system we showed that the interaction is mediated by the PDZ (PSD95-DlgA-ZO-1) domains of LNX proteins and the cytosolic C-terminal valine motif of CD8α. Moreover, CD8α redistributed LNX1 or LNX2 from the cytosol to the plasma membrane, whereas, remarkably, LNX1 or LNX2 promoted CD8α ubiquitylation, downregulation from the plasma membrane, transport to the lysosomes, and degradation. Our findings highlight the function of LNX proteins as E3 ligases and suggest a mechanism of regulation for CD8α localization at the plasma membrane by ubiquitylation and endocytosis.
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Affiliation(s)
- Massimo D'Agostino
- Dipartimento di Biochimica e Biotecnologie Mediche, University of Naples ‘Federico II’, Via S. Pansini 5, 80131 Naples, Italy
| | - Giusy Tornillo
- Dipartimento di Biochimica e Biotecnologie Mediche, University of Naples ‘Federico II’, Via S. Pansini 5, 80131 Naples, Italy
| | - Maria Gabriella Caporaso
- Dipartimento di Biochimica e Biotecnologie Mediche, University of Naples ‘Federico II’, Via S. Pansini 5, 80131 Naples, Italy
| | - Maria Vittoria Barone
- Dipartimento di Pediatria, European Laboratory For the Investigation of Food Induced Disease, University of Naples ‘Federico II’, Via S. Pansini 5, 80131 Naples, Italy
| | - Eric Ghigo
- URMITE, CNRS UMR6236-IRD 3R198, Université de la Méditerranée, 27 Bd Jean Moulin 13358 Marseille CEDEX 05, France
| | - Stefano Bonatti
- Dipartimento di Biochimica e Biotecnologie Mediche, University of Naples ‘Federico II’, Via S. Pansini 5, 80131 Naples, Italy
| | - Giovanna Mottola
- Dipartimento di Biochimica e Biotecnologie Mediche, University of Naples ‘Federico II’, Via S. Pansini 5, 80131 Naples, Italy
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8
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NKG2D ligand MICA is retained in the cis-Golgi apparatus by human cytomegalovirus protein UL142. J Virol 2009; 83:12345-54. [PMID: 19793804 DOI: 10.1128/jvi.01175-09] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) evades T-cell recognition by down-regulating expression of major histocompatibility complex (MHC) class I and II molecules on the surfaces of infected cells. Contrary to the "missing-self" hypothesis, HCMV-infected cells are refractory to lysis by natural killer (NK) cells. Inhibition of NK cell function is mediated by a number of HCMV immune evasion molecules, which operate by delivering inhibitory signals to NK cells and preventing engagement of activating ligands. One such molecule is UL142, which is an MHC class I-related glycoprotein encoded by clinical isolates and low-passage-number strains of HCMV. UL142 is known to down-modulate surface expression of MHC class I-related chain A (MICA), which is a ligand of the activating NK receptor NKG2D. However, the mechanism by which UL142 interferes with MICA is unknown. Here, we show that UL142 localizes predominantly to the endoplasmic reticulum (ER) and cis-Golgi apparatus. The transmembrane domain of UL142 mediates its ER localization, while we propose that the UL142 luminal domain is involved in its cis-Golgi localization. We also confirm that UL142 down-modulates surface expression of full-length MICA alleles while having no effect on the truncated allele MICA*008. However, we demonstrate for the first time that UL142 retains full-length MICA alleles in the cis-Golgi apparatus. In addition, we propose that UL142 interacts with nascent MICA en route to the cell surface but not mature MICA at the cell surface. Our data also demonstrate that the UL142 luminal and transmembrane domains are involved in recognition and intracellular sequestration of full-length MICA alleles.
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9
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Renna M, Faraonio R, Bonatti S, De Stefano D, Carnuccio R, Tajana G, Remondelli P. Nitric oxide-induced endoplasmic reticulum stress activates the expression of cargo receptor proteins and alters the glycoprotein transport to the Golgi complex. Int J Biochem Cell Biol 2006; 38:2040-8. [PMID: 16899390 DOI: 10.1016/j.biocel.2006.05.016] [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: 01/13/2006] [Revised: 05/15/2006] [Accepted: 05/27/2006] [Indexed: 11/28/2022]
Abstract
The endoplasmic reticulum Golgi intermediate compartment 53 protein recycles continuously between the endoplasmic reticulum and the Golgi complex and ensures the anterograde transport of specific glycoproteins with the assistance of the Multiple Clotting Factor Deficiency adaptor protein. Therefore, to analyze the effect of the endoplasmic reticulum stress on the secretory pathway beyond the endoplasmic reticulum, we analyzed the expression of both proteins in J774 macrophages incubated with the nitric oxide donor DETA NONOate or with thapsigargin. Both proteins accumulated progressively, by a transcriptional mechanism, in response to these inducers. Nitric oxide also induced a higher level of calreticulin and glucose regulated 78 protein, two endoplasmic reticulum proteins controlled by the unfolded protein response. Interestingly, nitric oxide induced the processing of the activating transcription factor 6alpha of the unfolded protein response, while thapsigargin also induced the activation of the transcription factor X-box Binding Protein 1. In addition, we showed that the accumulation of both transporters occurred simultaneously with the activation of endoplasmic reticulum-stress-dependent apoptosis, suggesting that these proteins may participate in the events that will eventually decide the fate of the cell. Induction of endoplasmic reticulum stress affected the rate of anterograde transport of a reporter glycoprotein, indicating that the endoplasmic reticulum to Golgi transport is remarkably impaired. Our results indicate that increased levels of cargo receptor proteins might have a function either in the quality control of protein folding in the endoplasmic reticulum or in the homeostasis of the intermediate compartment and Golgi complex during cell stress.
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Affiliation(s)
- Maurizio Renna
- Dipartimento di Biochimica e Biotecnologie Mediche, University of Naples Federico II, via S. Pansini 5, 1-80131 Naples, Italy
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10
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Op De Beeck A, Rouillé Y, Caron M, Duvet S, Dubuisson J. The transmembrane domains of the prM and E proteins of yellow fever virus are endoplasmic reticulum localization signals. J Virol 2004; 78:12591-602. [PMID: 15507646 PMCID: PMC525104 DOI: 10.1128/jvi.78.22.12591-12602.2004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The immature flavivirus particle contains two envelope proteins, prM and E, that are associated as a heterodimer. Virion morphogenesis of the flaviviruses occurs in association with endoplasmic reticulum (ER) membranes, suggesting that there should be accumulation of the virion components in this compartment. This also implies that ER localization signals must be present in the flavivirus envelope proteins. In this work, we looked for potential subcellular localization signals in the yellow fever virus envelope proteins. Confocal immunofluorescence analysis of the subcellular localization of the E protein in yellow fever virus-infected cells indicated that this protein accumulates in the ER. Similar results were obtained with cells expressing only prM and E. Chimeric proteins containing the ectodomain of CD4 or CD8 fused to the transmembrane domains of prM or E were constructed, and their subcellular localization was studied by confocal immunofluorescence and by analyzing the maturation of their associated glycans. Although a small fraction was detected in the ER-to-Golgi intermediate and Golgi compartments, these chimeric proteins were located mainly in the ER. The C termini of prM and E form two antiparallel transmembrane alpha-helices. Interestingly, the first transmembrane passage contains enough information for ER localization. Taken altogether, these data indicate that, besides their role as membrane anchors, the transmembrane domains of yellow fever virus envelope proteins are ER retention signals. In addition, our data show that the mechanisms of ER retention of the flavivirus and hepacivirus envelope proteins are different.
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Affiliation(s)
- Anne Op De Beeck
- Unité Hépatite C, CNRS-UPR2511, Institut de Biologie de Lille, 1 rue Calmette, BP447, 59021 Lille cedex, France
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11
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Spatuzza C, Renna M, Faraonio R, Cardinali G, Martire G, Bonatti S, Remondelli P. Heat Shock Induces Preferential Translation of ERGIC-53 and Affects Its Recycling Pathway. J Biol Chem 2004; 279:42535-44. [PMID: 15292203 DOI: 10.1074/jbc.m401860200] [Citation(s) in RCA: 22] [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
ERGIC-53 is a lectin-like transport receptor protein, which recirculates between the ER and the Golgi complex and is required for the intracellular transport of a restricted number of glycoproteins. We show in this article that ERGIC-53 accumulates during the heat shock response. However, at variance with the unfolded protein response, which results in enhanced transcription of ERGIC-53 mRNA, heat shock leads only to enhanced translation of ERGIC-53 mRNA. In addition, the half-life of the protein does not change during heat shock. Therefore, distinct signal pathways of the cell stress response modulate the ERGIC-53 protein level. Heat shock also affects the recycling pathway of ERGIC-53. The protein rapidly redistributes in a more peripheral area of the cell, in a vesicular compartment that has a lighter sedimentation density on sucrose gradient in comparison to the compartment that contains the majority of ERGIC-53 at 37 degrees C. This effect is specific, as no apparent reorganization of the endoplasmic reticulum, intermediate compartment and Golgi complex is morphologically detectable in the cells exposed to heat shock. Moreover, the anterograde transport of two unrelated reporter proteins is not affected. Interestingly, MCFD2, which interacts with ERGIC-53 to form a complex required for the ER-to-Golgi transport of specific proteins, is regulated similarly to ERGIC-53 in response to cell stress. These results support the view that ERGIC-53 alone, or in association with MCFD2, plays important functions during cellular response to stress conditions.
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MESH Headings
- 5' Untranslated Regions
- Base Sequence
- Biological Transport
- Blotting, Northern
- Blotting, Western
- Carrier Proteins/metabolism
- Cell Line
- Centrifugation, Density Gradient
- Electrophoresis, Polyacrylamide Gel
- Endoplasmic Reticulum/metabolism
- Fluorescent Antibody Technique, Indirect
- Gene Expression Regulation
- Genes, Reporter
- Genistein/pharmacology
- Glycoproteins/metabolism
- Golgi Apparatus/metabolism
- Hot Temperature
- Humans
- Immunoblotting
- Immunoprecipitation
- Lectins/metabolism
- Mannose-Binding Lectins/genetics
- Mannose-Binding Lectins/physiology
- Membrane Proteins/genetics
- Membrane Proteins/physiology
- Microscopy, Electron
- Microscopy, Fluorescence
- Molecular Sequence Data
- Promoter Regions, Genetic
- Protein Binding
- Protein Biosynthesis
- Protein Structure, Tertiary
- Quercetin/pharmacology
- RNA/metabolism
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Sucrose/pharmacology
- Temperature
- Time Factors
- Transcriptional Activation
- Transfection
- Vesicular Transport Proteins
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Affiliation(s)
- Carmen Spatuzza
- Dipartimento di Biochimica e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, I-80131, Naples, Italy
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12
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Iodice L, Sarnataro S, Bonatti S. The carboxyl-terminal valine is required for transport of glycoprotein CD8 alpha from the endoplasmic reticulum to the intermediate compartment. J Biol Chem 2001; 276:28920-6. [PMID: 11384990 DOI: 10.1074/jbc.m103558200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
There is evidence that a carboxyl-terminal valine residue is an anterograde transport signal for type I transmembrane proteins. Removal of the signal would either delay glycosylation in the Golgi complex of proteins destined to recycle to the endoplasmic reticulum or determine accumulation in the endoplasmic reticulum of newly synthesized proteins destined for the plasma membrane. We used the human CD8 alpha glycoprotein to investigate the role of the carboxyl-terminal valine in the exocytic pathway. Using immunofluorescence light microscopy, metabolic labeling, and cell fractionation, we demonstrate that removal of the carboxyl-terminal valine residue delays transport of CD8 alpha from the endoplasmic reticulum to the intermediate compartment. Removal of the residue did not affect the other steps of the exocytic pathway or the folding/dimerization and glycosylation processes. Therefore, it is likely that this signal plays a role in the transport of CD8 alpha from the endoplasmic reticulum to the intermediate compartment either before or during the formation of the transport vesicles that drive the exit the protein from the endoplasmic reticulum.
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Affiliation(s)
- L Iodice
- Department of Biochemistry and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy
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13
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Bermak JC, Li M, Bullock C, Zhou QY. Regulation of transport of the dopamine D1 receptor by a new membrane-associated ER protein. Nat Cell Biol 2001; 3:492-8. [PMID: 11331877 DOI: 10.1038/35074561] [Citation(s) in RCA: 210] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Many structural determinants for G protein-coupled receptor (GPCR) functions have been defined, but little is known concerning the regulation of their transport from the endoplasmic reticulum (ER) to the cell surface. Here we show that a carboxy-terminal hydrophobic motif, FxxxFxxxF, which is highly conserved among GPCRs, functions independently as an ER-export signal for the dopamine D1 receptor. A newly identified ER-membrane-associated protein, DRiP78, binds to this motif. Overexpression or sequestration of DRiP78 leads to retention of D1 receptors in the ER, reduced ligand binding, and a slowdown in the kinetics of receptor glycosylation. Our results indicate that DRiP78 may regulate the transport of a GPCR by binding to a specific ER-export signal.
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Affiliation(s)
- J C Bermak
- Department of Pharmacology, University of California, Irvine, California 92697, USA
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14
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Abstract
To investigate whether human immunodeficiency virus (HIV)-1 and HIV-1 antigens modulate surface and cytoplasmic CD8 or CD3, as well as CD4, we used cell permeabilization reagents, surface/cytoplasmic fluorescent staining, multiparameter flow cytometric techniques and an in vitro culture system in which relatively few lymphocytes are actively infected with HIV. Human peripheral blood lymphocytes were: not stimulated, not stimulated but HIV-inoculated, phytohaemagglutinin (PHA)-stimulated, PHA/HIV-inoculated (PHA/HIV), or placed into media with soluble gp120, Rev or Nef. HIV inoculation and Nef had striking modulatory effects on CD8. The cytoplasmic CD8 median fluorescent intensity (MFI) of positive lymphocytes was lower for cells in unstimulated/HIV-infected cultures than unstimulated cultures (44 versus 62% of ex vivo value, P = 0.032) and lower for cells in PHA/HIV cultures than in PHA cultures (56 versus 100% of ex vivo, P = 0.041). The surface CD8 MFI values for Nef were significantly lower than the ex vivo value (75% of ex vivo, P = 0.006). At days 2-7 of culture, Rev was associated with slight reductions in surface CD4 MFI (58% of ex vivo versus 78% of ex vivo for unstimulated cultures, P = 0.047) and greater effects on cytoplasmic CD3 MFI (131 versus 179% of ex vivo for unstimulated cultures, P = 0.035), and surface CD8 MFI (70% of ex vivo, P = 0.006 versus ex vivo value). The globality of Rev's effects suggests these are related to a shared processing pathway, i.e. not due to direct interaction with CD3, CD4 and CD8; the effects of HIV inoculation and Nef on CD8 expression appear to be more CD8 specific. Because CD8 is essential for cytotoxic T-cell function, its down-modulation could inhibit this activity, including anti-HIV cytotoxicity. Given the critical roles of CD3 and CD8 in T-lymphocyte signal transduction and antigen responsiveness, the effects of HIV, Rev and Nef on these molecules have clinically significant implications concerning the pathogenesis and treatment of HIV.
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Affiliation(s)
- J Jason
- Mailstop A-25, Immunology Branch, DASTLR/NCID, Centers for Disease Control and Prevention, Department of Health and Human Services, Public Health Service, 1600 Clifton Road NE, Atlanta, GA 30333, USA.
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15
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Pascale MC, Remondelli P, Leone A, Bonatti S. Assembly of the CD8alpha/p56(lck) protein complex in stably expressing rat epithelial cells. FEBS Lett 2000; 480:226-30. [PMID: 11034334 DOI: 10.1016/s0014-5793(00)01945-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have previously characterized the biogenesis of the human CD8alpha protein expressed in rat epithelial cells. We now describe the biosynthesis, post-translational maturation and hetero-oligomeric assembly of the human CD8alpha/p56(lck) protein complex in stable transfectants obtained from the same cell line. There were no differences in the myristilation of p56(lck), or in the dimerization, O-glycosylation and transport to the plasma membrane of CD8alpha, between cells expressing either one or both proteins. In the doubly expressing cells, dimeric forms of CD8alpha established hetero-oligomeric complexes with p56(lck), as revealed by co-immunoprecipitation assays performed with anti-CD8alpha antibody. Moreover, p56(lck) bound in these hetero-oligomeric complexes was endowed with auto- and hetero-phosphorylating activity. The present study shows that: (1) the newly synthesized p56(lck) binds rapidly to CD8alpha and most of the p56(lck) is bound to CD8alpha at steady state; (2) CD8alpha/p56(lck) protein complexes are formed at internal membranes as well as at the plasma membrane; and (3) about 50% of complexed p56(lck) reaches the cell surface.
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Affiliation(s)
- M C Pascale
- Dipartimento di Scienze Farmaceutiche, Università di Salerno, Fisciano-Salerno, Italy
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16
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Mottola G, Jourdan N, Castaldo G, Malagolini N, Lahm A, Serafini-Cessi F, Migliaccio G, Bonatti S. A new determinant of endoplasmic reticulum localization is contained in the juxtamembrane region of the ectodomain of hepatitis C virus glycoprotein E1. J Biol Chem 2000; 275:24070-9. [PMID: 10783397 DOI: 10.1074/jbc.m910400199] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Hepatitis C virus glycoproteins E1 and E2 do not reach the plasma membrane of the cell but accumulate intracellularly, mostly in the endoplasmic reticulum. Previous studies based on transient expression assays have shown that the transmembrane domains of both glycoproteins are sufficient to localize reporter proteins in the endoplasmic reticulum and that other localization signals may be contained in the ectodomain of E1 protein. To identify such signals we generated chimeric proteins between E1 and two reporter proteins, the human CD8 glycoprotein and the human alkaline phosphatase, and analyzed their subcellular localization in stable as well as transient transfectants. Our results showed that (i) an independent localization determinant for the endoplasmic reticulum is present in the juxtamembrane region of the ectodomain of E1 protein and (ii) the localization dictated by this determinant is either due to direct retention or to a recycling mechanism from the intermediate compartment/cis-Golgi complex region, which is clearly different from those previously described for other retrieval signals. These results show for the first time in mammalian cells that the localization in the endoplasmic reticulum of transmembrane protein can be determined by specific targeting signals acting in the lumen of the compartment.
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Affiliation(s)
- G Mottola
- Dipartimento di Biochimica e Biotecnologie Mediche, Università di Napoli Federico II, 80131 Napoli, Italy
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17
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Kern P, Hussey RE, Spoerl R, Reinherz EL, Chang HC. Expression, purification, and functional analysis of murine ectodomain fragments of CD8alphaalpha and CD8alphabeta dimers. J Biol Chem 1999; 274:27237-43. [PMID: 10480942 DOI: 10.1074/jbc.274.38.27237] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Soluble mouse CD8alphaalpha and CD8alphabeta dimers corresponding to the paired ectodomains (CD8(f)) or their respective component Ig-like domains (CD8) were expressed in Chinese hamster ovary cells or the glycosylation variant Lec3.2.8.1 cells as secreted proteins using a leucine zipper strategy. The affinity of CD8alphaalpha(f) for H-2K(b) as measured by BIAcore revealed a approximately 65 microM K(d), similar to that of CD8alphabeta(f). Consistent with this result, CD8alphaalpha(f) as well as CD8alphabeta(f) blocked the effector function of N15 T cell receptor transgenic cytolytic T cells in a comparable, dose-dependent fashion. Furthermore, both Lec3.2.8.1-produced and Chinese hamster ovary-produced CD8 homodimers and heterodimers were active in the inhibition assay. These results suggest that the Ig-like domains of CD8 molecules are themselves sufficient to block the requisite transmembrane CD8-pMHC interaction between cytolytic T lymphocytes and target cells. Moreover, given the similarities in co-receptor affinities for pMHC, the findings suggest that the greater efficiency of CD8alphabeta versus CD8alphaalpha co-receptor function on T cells is linked to differences within their membrane-bound stalk regions and/or intracellular segments. As recently shown for sCD8alphaalpha, the yield, purity and homogeneity of the deglycosylated protein resulting from this expression system is sufficient for crystallization and x-ray diffraction at atomic resolution.
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Affiliation(s)
- P Kern
- Laboratory of Immunobiology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA
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18
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Lotti LV, Mottola G, Torrisi MR, Bonatti S. A different intracellular distribution of a single reporter protein is determined at steady state by KKXX or KDEL retrieval signals. J Biol Chem 1999; 274:10413-20. [PMID: 10187831 DOI: 10.1074/jbc.274.15.10413] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To establish the specific contribution to protein topology of KKXX and KDEL retrieval motifs, we have determined by immunogold electron microscopy and cell fractionation the intracellular distribution at steady state of the transmembrane and anchorless versions of human CD8 protein, tagged with KKXX (CD8-E19) and KDEL (CD8-K), respectively, and stably expressed in epithelial rat cells (Martire, G., Mottola, G., Pascale, M. C., Malagolini, N., Turrini, I., Serafini-Cessi, F., Jackson, M. R., and Bonatti, S. (1996) J. Biol. Chem. 271, 3541-3547). The CD8-E19 protein is represented by a single form, initially O-glycosylated: only about half of it is located in the endoplasmic reticulum, whereas more than 30% of the total is present in the intermediate compartment and cis-Golgi complex. In the latter compartments, CD8-E19 colocalizes with beta-coat protein (COP) (COPI component) and shows the higher density of labeling. Conversely, about 90% of the total CD8-KDEL protein is localized in clusters on the endoplasmic reticulum, where significant co-localization with Sec-23p (COPII component) is observed, and unglycosylated and initially O-glycosylated forms apparently constitute a single pool. Altogether, these results suggest that KKXX and KDEL retrieval motifs have different topological effects on theirs own at steady state: the first results in a specific enrichment in the intermediate compartment and cis-Golgi complex, and the latter dictates residency in the endoplasmic reticulum.
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Affiliation(s)
- L V Lotti
- Istituto Nazionale Ricerca sul Cancro di Genova, Sezione di Biotecnologie, Viale Regina Elena 324, 00161, Rome, Italy
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19
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Cocquerel L, Duvet S, Meunier JC, Pillez A, Cacan R, Wychowski C, Dubuisson J. The transmembrane domain of hepatitis C virus glycoprotein E1 is a signal for static retention in the endoplasmic reticulum. J Virol 1999; 73:2641-9. [PMID: 10074109 PMCID: PMC104019 DOI: 10.1128/jvi.73.4.2641-2649.1999] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/1998] [Accepted: 12/16/1998] [Indexed: 11/20/2022] Open
Abstract
Hepatitis C virus (HCV) glycoproteins E1 and E2 assemble to form a noncovalent heterodimer which, in the cell, accumulates in the endoplasmic reticulum (ER). Contrary to what is observed for proteins with a KDEL or a KKXX ER-targeting signal, the ER localization of the HCV glycoprotein complex is due to a static retention in this compartment rather than to its retrieval from the cis-Golgi region. A static retention in the ER is also observed when E2 is expressed in the absence of E1 or for a chimeric protein containing the ectodomain of CD4 in fusion with the transmembrane domain (TMD) of E2. Although they do not exclude the presence of an intracellular localization signal in E1, these data do suggest that the TMD of E2 is an ER retention signal for HCV glycoprotein complex. In this study chimeric proteins containing the ectodomain of CD4 or CD8 fused to the C-terminal hydrophobic sequence of E1 were shown to be localized in the ER, indicating that the TMD of E1 is also a signal for ER localization. In addition, these chimeric proteins were not processed by Golgi enzymes, indicating that the TMD of E1 is responsible for true retention in the ER, without recycling through the Golgi apparatus. Together, these data suggest that at least two signals (TMDs of E1 and E2) are involved in ER retention of the HCV glycoprotein complex.
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Affiliation(s)
- L Cocquerel
- CNRS-UMR319, IBL/Institut Pasteur de Lille, 59021 Lille Cedex, France
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20
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Nickel W, Malsam J, Gorgas K, Ravazzola M, Jenne N, Helms JB, Wieland FT. Uptake by COPI-coated vesicles of both anterograde and retrograde cargo is inhibited by GTPgammaS in vitro. J Cell Sci 1998; 111 ( Pt 20):3081-90. [PMID: 9739081 DOI: 10.1242/jcs.111.20.3081] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
On the basis of the cell surface protein CD8 we have constructed reporter molecules for both anterograde and retrograde transport from the Golgi complex. The cytoplasmic tail of CD8 was exchanged by a construct comprising a hemagglutinin (HA) epitope, the C-terminal sequence of the viral protein E19 (containing a KKXX retrieval signal) followed by a myc epitope (CD8-LT). Due to this masking of the KKXX retrieval signal CD8-LT is transported to the cell surface. Since the KKXX motif is joined to the myc epitope via a thrombin cleavage site, CD8-LT in isolated Golgi membranes can be proteolytically converted into an unmasked reporter molecule for retrograde transport (CD8-ST) in vitro. A CHO cell line stably expressing CD8-LT was generated and used for the isolation of Golgi membranes. These membranes were shown to contain CD8-LT en route to the cell surface. By addition of thrombin, CD8-LT could be efficiently converted into CD8-ST, and this allows us to study the sorting into coat protein COPI-coated vesicles of these different kinds of cargo on a comparative basis. COPI-coated vesicles were generated in vitro from Golgi membranes containing either CD8-LT or CD8-ST. When the incubation was performed in the presence of GTP, both CD8-LT and CD8-ST were packaged into COPI-coated vesicles. However, COPI-coated vesicles generated in the presence of the slowly hydrolyzable analogue of GTP, GTP(γ)S contained strikingly lower amounts of CD8-LT and CD8-ST. While COPI-coated vesicles accumulated about 12-fold in the presence of GTPgammaS these vesicles together contained only one fifth of cargo compared to the few vesicles generated in the absence of GTPgammaS. These data indicate that cargo packaging into COPI-coated vesicles requires hydrolysis of GTP.
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Affiliation(s)
- W Nickel
- Biochemie-Zentrum Heidelberg (BZH), Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 328, Germany
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21
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Nickel W, Sohn K, Bünning C, Wieland FT. p23, a major COPI-vesicle membrane protein, constitutively cycles through the early secretory pathway. Proc Natl Acad Sci U S A 1997; 94:11393-8. [PMID: 9326620 PMCID: PMC23477 DOI: 10.1073/pnas.94.21.11393] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A novel type I transmembrane protein of COPI-coated vesicles, p23, has been demonstrated to be localized mainly to the Golgi complex. This protein and p24, another member of the p24 family, have been shown to bind coatomer via their short cytoplasmic tails. Here we demonstrate that p23 continuously cycles through the early secretory pathway. The cytoplasmic tail of p23 is shown to act as a functional retrieval signal as it confers endoplasmic reticulum (ER) residence to a CD8-p23 fusion protein. This ER localization is, at least in part, a result of retrieval from post-ER compartments because CD8-p23 fusion proteins receive post-ER modifications. In contrast, the cytoplasmic tail of p24 has been shown not to retrieve a CD8-p24 fusion protein. The coatomer binding motifs FF and KK in the cytoplasmic tail of p23 are reported to influence the steady-state localization of the CD8-p23 fusion protein within the ER-Golgi recycling pathway. It appears that the steady-state Golgi localization of endogenous p23 is maintained by its lumenal domain, as a fusion protein with the lumenal domain of CD8, and the membrane span as well as the cytoplasmic tail of p23 is no longer detected in the Golgi.
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Affiliation(s)
- W Nickel
- Biochemie-Zentrum Heidelberg, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany.
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22
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Abstract
Members of the p24 family of putative cargo receptors are proposed to contain retrograde and anterograde trafficking signals in their cytoplasmic domain to facilitate coat protein binding and cycling in the secretory pathway. We have analyzed the role of the transmembrane domain (TMD) of a p24 protein isolated from COPI-coated intra-Golgi transport vesicles. CD8-p24 chimeras were transiently expressed in COS7 cells and analyzed by immunofluorescence and pulse-chase experiments. The localization and transit of the wild-type chimera from the endoplasmic reticulum (ER) through the Golgi complex involved a glutamic acid residue and a conserved glutamine in the TMD. The TMD glutamic acid mediated the localization of the chimeras to the ER in the absence of the conserved glutamine. Efficient ER exit required the TMD glutamine and was further facilitated by a pair of phenylalanine residues in the cytoplasmic tail. TMD residues of p24 proteins may mediate the interaction with integral membrane proteins of the vesicle budding machinery to ensure p24 packaging into transport vesicles.
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Affiliation(s)
- K Fiedler
- Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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23
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Ramachandran U, Peterkofsky B. Aberrant O-glycosylation in the collagenous domain of pro alpha2(I) procollagen subunits synthesized by chemically transformed hamster fibroblasts. Arch Biochem Biophys 1997; 342:29-37. [PMID: 9185611 DOI: 10.1006/abbi.1997.0101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chemically transformed Syrian hamster embryo fibroblasts (NQT-SHE) do not synthesize the pro alpha1(I) subunit of type I collagen, but they secrete two forms of the pro alpha2(I) subunit (N33 and N50) with abnormal post-translational modifications localized in the alpha2CB3,5 cyanogen bromide peptide of the collagenous domain (B. Peterkofsky and W. Prather (1992) J. Biol. Chem. 267 5388-5395). Isoelectric focusing and treatment of the modified chains with glycosidases and biotinylated Jacalin lectin identified the modifications as Gal beta1,3-GalNAc-O-Ser/Thr with or without a terminal sialic acid in an alpha2,6 linkage. Unhydroxylated N33 alpha-chains also reacted with Jacalin, confirming that the abnormal modification was O-glycosylation and not hyperhydroxylation of proline or lysine. Cells were treated with benzyl GalNAc, a competitive inhibitor of galactosyl transferase that prevents addition of Gal to GalNAc-O-Ser/Thr and thus blocks elongation of O-glycosyl chains. Treated cells secreted pro alpha2(I) chains containing GalNAc-O-Ser/Thr but no galactose or sialic acid, which suggested that Gal addition takes place before sialylation. Treatment of NQT-SHE cells with monensin and brefeldin A inhibited secretion and led to intracellular accumulation of pro alpha2(I) chains that contained only GalNAc. Therefore, it appears that GalNAc addition to pro alpha2(I) chains in NQT-SHE cells occurs in the cis-Golgi, while sialic acid and galactose are added in the trans-Golgi network. The pro alpha2(I) chains produced by NQT-SHE cells most likely are modified because they are in the denatured state, and thus potential O-glycosylation sites become available that would not be exposed in normal triple helical procollagen.
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Affiliation(s)
- U Ramachandran
- Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892-4255, USA
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24
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Fiedler K, Veit M, Stamnes MA, Rothman JE. Bimodal interaction of coatomer with the p24 family of putative cargo receptors. Science 1996; 273:1396-9. [PMID: 8703076 DOI: 10.1126/science.273.5280.1396] [Citation(s) in RCA: 258] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Cytoplasmic domains of members of the p24 family of putative cargo receptors were shown to bind to coatomer, the coat protein of COPI-coated transport vesicles. Domains that contained dilysine endoplasmic reticulum retrieval signals bound the alpha-, beta'-, and epsilon-COP subunits of coatomer, whereas other p24 domains bound the beta-, gamma-, and zeta-COP subunits and required a phenylalanine-containing motif. Transit of a CD8-p24 chimera from the endoplasmic reticulum through the Golgi complex was slowed when the phenylalanine motif was mutated, suggesting that this motif may function as an anterograde transport signal. The either-or bimodal binding of coatomer to p24 tails suggests models for how coatomer can potentially package retrograde-directed and anterograde-directed cargo into distinct COPI-coated vesicles.
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Affiliation(s)
- K Fiedler
- Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA
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25
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Martire G, Mottola G, Pascale MC, Malagolini N, Turrini I, Serafini-Cessi F, Jackson MR, Bonatti S. Different fate of a single reporter protein containing KDEL or KKXX targeting signals stably expressed in mammalian cells. J Biol Chem 1996; 271:3541-7. [PMID: 8631959 DOI: 10.1074/jbc.271.7.3541] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In mammalian cells, resident luminal and type I transmembrane proteins of the endoplasmic reticulum usually contain KDEL and KKXX at the carboxyl terminus. These sequences induce retrieval from compartments located downstream in the secretory pathway. It has been suggested that the retrieval may occur from multiple sites, ranging from the intermediate compartment to the trans-Golgi network. To compare the retrieval of luminal and type I membrane proteins, we have used different forms of a single reporter, the human CD8 glycoprotein, stably expressed in FRT cells. Metabolic labeling and oligosaccharide analysis show that the mechanism based on the KDEL signal is leaky. With time, the KDEL-containing CD8 form reaches the trans/trans-Golgi network compartments, where the protein is terminally glycosylated. At this stage, the retrieval mechanism stops being effective and the protein is consequently secreted. Conversely, the mechanism based on the KKXX signal guarantees that most of the KKXX-containing CD8 form resides in the endoplasmic reticulum, little in the Golgi complex and undetectable levels at the plasma membrane. The O-glycosylation of this protein comprises for the vast majority the sole addition of peptide-bound GalNAc that occurs in an early Golgi compartment.
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Affiliation(s)
- G Martire
- Dipartimento di Biochimica e Biotecnologie Mediche, Università di Napoli "Federico II," 80131 Naples, Italy
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26
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Balow JP, Kerase KP. Isolation of newly expressed surface T cell antigen receptor complexes by serial precipitation with anti-TCR antibodies and immobilized streptavidin. J Immunol Methods 1996; 189:251-8. [PMID: 8613676 DOI: 10.1016/0022-1759(95)00255-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Expression of the multisubunit T cell antigen receptor (TCR) complex is an enigmatic process requiring coordinated regulation of at least six different gene products (alpha, beta, gamma, delta, epsilon, and zeta), the ordered pairing of partner chains within the endoplasmic reticulum (ER), and intracellular transport of complete, but not incomplete, TCR complexes to the cell surface. Movement of nascent TCR glycoproteins from the ER to the Golgi compartment is easily studied using various lectins and/or glycosidases specific for oligosaccharide modifications that occur within the Golgi system. In contrast, cell surface transport of TCR complexes is relatively difficult to assess, since this requires physical separation of intracellular complexes from surface TCR complexes. In the current report we describe a method for the isolation of newly transported surface TCR complexes which utilizes metabolic and surface techniques in conjunction with serial precipitation methods. Specifically, we describe the use of anti-TCR antibodies and immobilized streptavidin to isolate nascent TCR alpha proteins localized on the plasma membrane. This technique is rapid, specific, and provides a novel approach for studying the intracellular transport of nascent immune receptor molecules to the cell surface.
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Affiliation(s)
- J P Balow
- National Cancer Institute, National Institute of Health, Building 10, Room 3N119, Bethesda, MD 20892-1260, USA
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27
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Glycosylation and Maturation Rate of Membrane and Secretory Forms of Human CD8α Glycoprotein. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995. [DOI: 10.1007/978-1-4615-1885-3_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Mancini P, Lotti LV, Pascale MC, Bonatti S, Torrisi MR. Surface distribution and partition during freeze-fracture of CD8 antigens on human lymphocytes and on epithelial transfected cells. HISTOCHEMISTRY 1994; 102:51-7. [PMID: 7814270 DOI: 10.1007/bf00271049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Freeze-fracture immunocytochemistry was used to analyse the surface distribution, redistribution induced by antibodies, and partition during freeze-fracture, of CD8 molecules on human T lymphocytes and rat epithelial transfected (FRT-U10) cells. Immunogold labelling of CD8 antigens was uniform over the unfractured cell surfaces of both lymphocytes and epithelial transfected cells. After freeze-fracture, the gold particles were associated with the exoplasmic outer leaflets of the plasma membranes in both cell types. In lymphocytes, incubation with antibodies at 37 degrees C up to 20 min induced patching and capping of the antigens on the unfractured cell surface. After fracture, the patched molecules appeared associated with the protoplasmic inner leaflet of the plasma membranes. Parallel antibody-treatment at 37 degrees C of FRT-U10 cells induced clustering of CD8 molecules but failed to cause further aggregation in larger patches or in caps. After freeze-fracture, the immunolabelling was clustered, but associated with the exoplasmic outer leaflet of the plasma membranes as in untreated cells. The different redistribution induced by antibodies and the different behaviour on fracture of the redistributed molecules in the two cell types may be regulated by CD8 interaction with the cytoskeleton.
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Affiliation(s)
- P Mancini
- Dipartimento di Medicina Sperimentale, Università di Roma, Italy
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29
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Kumagai AK, Dwyer KJ, Pardridge WM. Differential glycosylation of the GLUT1 glucose transporter in brain capillaries and choroid plexus. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1193:24-30. [PMID: 8038191 DOI: 10.1016/0005-2736(94)90328-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The sodium-independent GLUT1 glucose transporter is expressed in high density in human erythrocytes and in tissues which serve a barrier function. In the polarized endothelial cells of the brain capillaries, which comprise the blood-brain barrier (BBB), GLUT1 is expressed on both apical and basolateral membranes; however, in the epithelium of the choroid plexus, GLUT1 expression is restricted to the basolateral surface. The present study examined whether these differences in subcellular localization of GLUT1 at the BBB and choroid plexus could be correlated with differential N-linked or O-linked glycosylation of the protein. Western blot analysis of solubilized brain capillaries (BC) and choroid plexus (CP) revealed that while the BC GLUT1 had an average molecular mass identical to that of the purified human erythrocyte transporter (54 kDa), the CP GLUT1 was of lower molecular mass (47 kDa). Treatment of brain capillaries and choroid plexus with N-glycanase resulted in a shift in the mobility of the GLUT1 of both samples to a lower molecular mass of 42 kDa; however, in contrast, treatment with O-glycanase produced no change in the mobility patterns of GLUT1, but did result in O-linked deglycosylation of another BBB marker, gamma-glutamyl transpeptidase. In conclusion, BBB and choroid plexus GLUT1 are subject to differential N-linked glycosylation with the protein having an N-linked carbohydrate side chain of higher molecular mass at the BBB in comparison to the choroid plexus.
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Affiliation(s)
- A K Kumagai
- Department of Medicine, UCLA School of Medicine 90024
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30
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Påhlsson P, Blackall DP, Ugorski M, Czerwinski M, Spitalnik SL. Biochemical characterization of the O-glycans on recombinant glycophorin A expressed in Chinese hamster ovary cells. Glycoconj J 1994; 11:43-50. [PMID: 8193553 DOI: 10.1007/bf00732431] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Alterations in N- and O-linked glycosylation affect cell surface expression and antigenicity of recombinant glycophorin A expressed in transfected Chinese hamster ovary (CHO) cells. To understand these effects further, glycophorin A was purified by immunoaffinity chromatography from transfected wild type and glycosylation deficient CHO cells. The O-glycans were characterized both biochemically, using gel filtration and high performance anion exchange chromatography, and immunologically, using carbohydrate specific monoclonal antibodies to probe Western blots. The O-glycans of human erythrocyte glycophorin A consist mainly of short oligosaccharides with one, two, or three sialic acid residues linked to a common disaccharide core, Gal beta 1-3GalNAc alpha 1-Ser/Thr, with the disialylated structure being the most abundant. With the exception of the trisialylated derivative, the same structures were found on recombinant glycophorin A expressed by wild type CHO cells. However, in contrast to human erythrocyte glycophorin A, the monosialylated oligosaccharide was the most abundant structure on the recombinant protein. Furthermore, recombinant glycophorin A was shown to express a small amount of the Tn antigen (GalNAc alpha 1-Ser/Thr). Recombinant glycophorin A had the same O-glycan composition, whether purified from clones expressing high or moderate levels of the recombinant glycoprotein. This indicates that the level of expression of the transfected glycoprotein did not affect its O-glycan composition. Deletion of the N-linked glycosylation site at Asn26, by introducing the Mi.I mutation (Thr28-->Met) by site-directed mutagenesis, did not markedly affect the O-glycan composition of the resulting recombinant glycoprotein expressed in wild type CHO cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P Påhlsson
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia 19104
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Schweizer A, Clausen H, van Meer G, Hauri H. Localization of O-glycan initiation, sphingomyelin synthesis, and glucosylceramide synthesis in Vero cells with respect to the endoplasmic reticulum-Golgi intermediate compartment. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)41738-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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32
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Bonatti S, Torrisi MR. The intermediate compartment between endoplasmic reticulum and Golgi complex in mammalian cells. Subcell Biochem 1993; 21:121-42. [PMID: 8256263 DOI: 10.1007/978-1-4615-2912-5_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- S Bonatti
- Department of Biochemistry and Medical Biotechnology, University of Naples Federico II, Italy
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