101
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Ou WJ, Cameron PH, Thomas DY, Bergeron JJ. Association of folding intermediates of glycoproteins with calnexin during protein maturation. Nature 1993; 364:771-6. [PMID: 8102790 DOI: 10.1038/364771a0] [Citation(s) in RCA: 431] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Calnexin, an endoplasmic reticulum transmembrane protein, represents a new type of molecular chaperone that selectively associates in a transient fashion with newly synthesized monomeric glycoproteins in HepG2 cells. Calnexin only recognizes glycoproteins when they are incompletely folded. Dissociation of glycoproteins from calnexin occurs at different rates and is related to the time taken for their folding, which may then initiate their differential transport rates from the endoplasmic reticulum.
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Affiliation(s)
- W J Ou
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
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102
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Abstract
The temperature sensitivity of nicotinic acetylcholine receptors (AChRs) from T. californica was used to identify steps in AChR subunit folding and oligomerization. Assembly intermediates were isolated by lowering to an assembly-permissive temperature. The earliest identifiable assembly intermediates, alpha beta gamma trimers, form minutes after subunit synthesis. alpha beta gamma delta tetramers are formed slowly by the addition of delta subunits to trimers, and finally a second alpha subunit is added to form alpha 2 beta gamma delta pentamers. Between these oligomerization steps, subunits fold as monitored by alpha-bungarotoxin-binding site formation, appearance of antigenic epitopes, changes in apparent molecular weight, and changes in detergent solubility. Subunit folding requires specific combinations of subunits and correlates in time with subunit additions, suggesting that these subunit folding events contribute to subunit recognition site formation during assembly.
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Affiliation(s)
- W N Green
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510
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103
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Roth J, Klöppel G, Madsen OD, Storch MJ, Heitz PU. Distribution patterns of proinsulin and insulin in human insulinomas: an immunohistochemical analysis in 76 tumors. ACTA ACUST UNITED AC 1993; 63:51-61. [PMID: 1362022 DOI: 10.1007/bf02899244] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The distribution of proinsulin and insulin immunoreactivity was studied in 76 human insulinomas and in normal pancreas. One trabecular and two solid insulinomas showed the staining pattern of normal beta cells. A "near normal" staining pattern (perinuclear proinsulin and diffuse or polarized insulin staining) existed in 10 of 27 trabecular and 11 of 44 solid insulinomas. An "intermediate" staining pattern (intense perinuclear as well as weaker diffuse proinsulin staining with diffuse or polarized insulin staining) was observed in 10 of 27 trabecular and 20 of 44 solid insulinomas. Different "abnormal" staining patterns were found in 6 of 27 trabecular and 6 of 44 solid insulinomas. Of the 5 glandular insulinomas, 4 exhibited a "near normal" and one an "abnormal" staining pattern. No correlation was found between any particular staining pattern and the multihormonality or malignancy of the insulinomas. The diffuse labeling for proinsulin in about 50% of the insulinomas is suggestive of abnormal prohormone processing.
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Affiliation(s)
- J Roth
- Department of Pathology, University of Zürich, Switzerland
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104
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Dupuis M, Peitsch MC, Hamann U, Stanley KK, Tschopp J. Mutations in the putative lipid-interaction domain of complement C9 result in defective secretion of the functional protein. Mol Immunol 1993; 30:95-100. [PMID: 8417379 DOI: 10.1016/0161-5890(93)90430-j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Complement protein C9 assembles with C5, C6, C7, C8 on the surface of target cells to form the lytic membrane attack complex (MAC). During MAC assembly and insertion into the target membrane, the hydrophilic, globular C9 partially unfolds to expose a hydrophobic lipid interaction domain. Several copies of amphiphilic C9 subsequently polymerize to form the characteristic ring-like MAC. Using a combined photoaffinity label and computer modeling approach, two amphipathic helices in a segment encompassing the amino acids 293-334 have been predicted to interact with membrane lipids. To elucidate the mechanism of C9 lipid binding and insertion, site-directed mutagenesis was used to change the amphipathic character of the helices. While some conservative amino acid replacements such as Thr307 by a Leu were tolerated and yielded fully active C9 when expressed in COS cells, successive changes of Leu305 into Val, Ala, and Glu on the hydrophobic site of the first helix gave rise to only partly or not secreted C9. All non-conservative amino acid replacements introduced on either side of the helices resulted in non-secreted C9 that was subsequently degraded intracellularly, indicating the importance of the correct folding of the presumptive transmembrane domain during biosynthesis. A natural secretion-incompetent mutant was found in which Val293, located in the proposed lipid-binding region, was lacking. Taken together, these findings suggest that the high incidence of homozygous C9 deficiencies may be due to a blockage in intracellular transport and secretion due to point mutations in this 'hot spot' region of the molecule.
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Affiliation(s)
- M Dupuis
- Institute of Biochemistry, University of Lausanne, Epalinges, Switzerland
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105
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Affiliation(s)
- S E Pontow
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110
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106
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Fourie AM, Coetzee GA, Gevers W, van der Westhuyzen DR. Low-density lipoprotein receptor point mutation results in expression of both active and inactive surface forms of the same mutant receptor. Biochemistry 1992; 31:12754-9. [PMID: 1463746 DOI: 10.1021/bi00166a007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
LDL receptors, expressed in cultured fibroblasts from patients homozygous for the FH Afrikaner-1 (FH1) mutation (Asp206 to Glu), are transported from the endoplasmic reticulum (ER) to the Golgi apparatus more slowly than in normal cells. In the present study, binding characteristics of FH1 cells for lipoprotein ligands (LDL and beta VLDL) and for receptor-specific monoclonal antibodies pointed to the existence of two surface forms of the same mutant receptor. One of these forms bound lipoproteins with normal high affinity whereas another did not. Binding studies of transfected hamster cells expressing only the mutant human gene confirmed the single-gene origin of the different forms. The existence of functionally distinct forms of the receptor protein was supported by the observation that only lipoprotein-binding receptor molecules were trapped intracellularly and degraded following ammonium chloride treatment of cells in the presence of ligand. The lipoprotein-binding receptor population was indistinguishable from normal receptors with respect to its affinity for LDL and beta VLDL, uptake and degradation of lipoprotein, and receptor recycling. Ligand blotting versus immunoblotting of receptors revealed normal-sized mutant receptors that were not recognized by lipoprotein ligand. Despite these differences, both mutant forms of the receptor were degraded at rates similar to those of normal receptors. We propose that the single amino acid substitution in this receptor interferes with the folding and/or posttranslational processing of precursor molecules in such a way that receptors adopt alternative stable structures.
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Affiliation(s)
- A M Fourie
- Department of Medical Biochemistry, University of Cape Town Medical School, South Africa
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107
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Pascale M, Erra M, Malagolini N, Serafini-Cessi F, Leone A, Bonatti S. Post-translational processing of an O-glycosylated protein, the human CD8 glycoprotein, during the intracellular transport to the plasma membrane. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)74024-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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108
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Callea F, Brisigotti M, Fabbretti G, Bonino F, Desmet VJ. Hepatic endoplasmic reticulum storage diseases. LIVER 1992; 12:357-62. [PMID: 1470006 DOI: 10.1111/j.1600-0676.1992.tb00589.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Endoplasmic Reticulum Storage Diseases (ERSD) represent a novel group of inborn errors of metabolism affecting secretory proteins and resulting in hepatocytic storage and plasma deficiency of the corresponding protein. The hepatocellular storage is due to a molecular abnormality hindering the translocation of the abnormal protein from the rough (RER) to the smooth endoplasmic reticulum (SER). The molecular abnormality is genetically determined; hence it is hereditary, congenital, familial and permanent. The storage is selective and exclusive for the mutant protein and predisposes to the development of chronic cryptogenic liver disease. ERSD include alpha-1-antitrypsin deficiency, fibrinogen storage and alpha-1-antichymotrypsin deficiency. Basically, the diagnosis of ERSD is a morphological one: immunohistochemistry and electron microscopy are essential tools for their identification.
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Affiliation(s)
- F Callea
- Department of Pathology, Children's Hospital G. Gaslini, Genova, Italy
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109
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Kupsch J, Saizawa KM, Eichmann K. Expression of murine soluble CD4 protein in baculovirus infected insect cells. Immunobiology 1992; 186:254-67. [PMID: 1490731 DOI: 10.1016/s0171-2985(11)80255-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The expression of murine soluble CD4 (L3T4) protein (sCD4) by baculovirus-infected insect cells was characterized. The yield of sCD4 reached 2 mg/l culture supernatant late in infection. Nevertheless, a large amount of sCD4 remained cell-associated, presumably in the endoplasmic reticulum or an early golgi compartment, as indicated by the endo-beta-N-acetyl-D-glucosaminidase H (endo-H) sensitivity of its carbohydrate chains. The secreted form of sCD4 is modified with both endo-beta-N-acetyl-D-glucosaminidase D (endo-D) and endo-H-sensitive oligosaccharides. It was possible that the incomplete secretion indicated faulty glycosylation or improper folding of the sCD4 protein. However, inhibitor studies showed that complete carbohydrate processing is not required for secretion of sCD4 by insect cells. Moreover, maintained reactivity with a panel of monoclonal Ab as well as phase partitioning experiments suggested that secretion is apparently not caused by misfolding of the sCD4 protein. Similar results were obtained with biologically active murine interleukin-4 produced by insect cells. This indicates that an inefficient secretory pathway may be a general problem of baculovirus-infected insect cells and is not a consequence of incorrect molecular conformation.
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Affiliation(s)
- J Kupsch
- Max-Planck-Institut für Immunbiologie, Freiburg, Germany
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110
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Baranski T, Cantor A, Kornfeld S. Lysosomal enzyme phosphorylation. I. Protein recognition determinants in both lobes of procathepsin D mediate its interaction with UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)50097-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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111
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Ljungdahl PO, Gimeno CJ, Styles CA, Fink GR. SHR3: a novel component of the secretory pathway specifically required for localization of amino acid permeases in yeast. Cell 1992; 71:463-78. [PMID: 1423607 DOI: 10.1016/0092-8674(92)90515-e] [Citation(s) in RCA: 165] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Mutations in SHR3 block amino acid uptake into yeast by reducing the levels of multiple amino acid permeases within the plasma membrane. SHR3 is a novel integral membrane protein component of the endoplasmic reticulum (ER). shr3 null mutants specifically accumulate amino acid permeases in the ER; other plasma membrane proteins, secretory proteins, and vacuolar proteins are processed and targeted correctly. Our findings suggest that SHR3 interacts with a structural domain shared by amino acid permeases, an interaction required for permease-specific processing and transport from the ER. Even in the presence of excess amino acids, shr3 mutants exhibit starvation responses. shr3 mutants constitutively express elevated levels of GCN4, and mutant shr3/shr3 diploids undergo dimorphic transitions that result in filamentous growth at enhanced frequencies.
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Affiliation(s)
- P O Ljungdahl
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142
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112
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Saraste J, Kuismanen E. Pathways of protein sorting and membrane traffic between the rough endoplasmic reticulum and the Golgi complex. SEMINARS IN CELL BIOLOGY 1992; 3:343-55. [PMID: 1457777 PMCID: PMC7128811 DOI: 10.1016/1043-4682(92)90020-v] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recent results have provided increasing evidence for the existence of an intermediate membrane compartment between the rough endoplasmic reticulum and the Golgi complex which seems to function in protein sorting and the regulation of membrane traffic in the early part of the exocytic pathway. Localization of resident marker proteins has shown that this compartment consists of both peripheral and central elements. The aim of the present review is to combine the data on the pre-Golgi compartment with previous ideas of membrane traffic at the ER-Golgi interface. We propose a model which describes how mobile, endosome-like elements of the pre-Golgi compartment function in the generation of the compositional and functional boundary between the widely distributed ER and the more centrally located Golgi stacks.
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Affiliation(s)
- J Saraste
- Ludwig Institute for Cancer Research, Stockholm Branch, Sweden
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113
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Pow DV, Morris JF. Tunicamycin, puromycin and brefeldin A influence the subcellular distribution of neuropeptides in hypothalamic magnocellular neurones of rat. Cell Tissue Res 1992; 269:547-60. [PMID: 1423514 DOI: 10.1007/bf00353909] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Magnocellular neurones in the supraoptic nuclei of normal Long Evans and homozygous Brattleboro rats were examined electron-microscopically after intracisternal injections of tunicamycin, puromycin, or brefeldin A. Moderate (50 micrograms) or high (200 micrograms) doses of tunicamycin caused the formation of electron-dense filamentous accretions in the endoplasmic reticulum (ER) cisterns of vasopressin neurones, but only the high dose of tunicamycin also caused accretions to form in the ER of some oxytocin neurones. Immunogold labelling of ultrathin sections from tunicamycin-treated rats revealed that, in about 5% of vasopressin neurones, the accretions could be immunogold-labelled for vasopressin and its associated neurophysin. However, in the majority of vasopressin neurones, the sections required trypsinisation before immunolabelling of the accretions could be detected. Small accretions in the ER of oxytocin neurones did not label for oxytocin or its neurophysin without prior trypsinisation, whereas larger accretions in other oxytocin cells could be labelled without prior trypsin treatment. Administration of puromycin resulted in the formation of small ER accretions in both vasopressin and oxytocin neurones. These accretions were immunolabelled with antisera, respectively, to vasopressin and oxytocin, but neurophysin-immunoreactivity was in most cases absent and was not revealed by treatment with trypsin, suggesting that neurophysin-immunoreactive epitopes were absent from truncated peptides forming the accretions. Brefeldin A caused dilatation of ER cisterns and disruption of the Golgi apparatus in both oxytocin and vasopressin neurones, but did not cause accretions to form in the ER.
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Affiliation(s)
- D V Pow
- Department of Human Anatomy, University of Oxford, UK
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114
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Kawaminami M, Tanaka K, Asawa T, Osugi S, Kawauchi H, Kurusu S, Hashimoto I. Association of annexin V with prolactin in the rat anterior pituitary gland. Biochem Biophys Res Commun 1992; 186:894-8. [PMID: 1386737 DOI: 10.1016/0006-291x(92)90830-e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
When pituitary extracts were subjected to non denaturing polyacrylamide gel electrophoresis, an unknown protein was found to associate with a proportion of the prolactin. This protein was dissociated from prolactin by sodium dodecyl sulfate. The protein was purified and sequenced. As the amino terminus was blocked, the amino acid sequences of three peptide fragments were determined. The obtained sequences of 41 amino acids were identical to partial sequences of a known protein, rat Annexin V. The molecular mass, 36 kDa, was also the same as the molecular weight of Annexin V. The existence of Annexin V mRNA in rat pituitary glands was also confirmed by polymerase chain reaction. These results show that Annexin V, a member of the calcium-dependent phospholipid binding proteins, is synthesized in the rat pituitary gland, and suggest its association with prolatin in the gland.
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Affiliation(s)
- M Kawaminami
- Laboratory of Veterinary Physiology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Aomori, Japan
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115
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Villalba J, Palmgren M, Berberián G, Ferguson C, Serrano R. Functional expression of plant plasma membrane H(+)-ATPase in yeast endoplasmic reticulum. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)49845-1] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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116
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Fujiwara T, Tsuji E, Misumi Y, Takami N, Ikehara Y. Selective cell-surface expression of dipeptidyl peptidase IV with mutations at the active site sequence. Biochem Biophys Res Commun 1992; 185:776-84. [PMID: 1351722 DOI: 10.1016/0006-291x(92)91693-k] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The cell surface expression of dipeptidyl peptidase IV (DPPIV) was examined in COS-1 cells transfected with its cDNA with or without mutations at the active site sequence Gly-Trp-Ser-Tyr-Gly (positions 629-633). Mutants with substitution of Trp630----Glu or Ser631----Ala were expressed on the cell surface as normally as the wild-type DPPIV, although the mutant with Ala631 had no enzyme activity. In contrast, any single substitutions of Gly at positions 629 and 633 resulted in no surface expression of the mutants, which were, instead, detected within the cells. When Tyr632 was substituted, one mutant (Tyr----Phe) was expressed on the surface, whereas the others (Tyr----Gly or Leu) were intracellularly retained. These results indicate that the surface expression of DPPIV is critically influenced by mutations at the active site sequence.
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Affiliation(s)
- T Fujiwara
- Department of Biochemistry, Fukuoka University School of Medicine, Japan
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117
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Endogenous glycosphingolipids move to the cell surface at a rate consistent with bulk flow estimates. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)49798-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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118
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Lodish H, Kong N, Wikström L. Calcium is required for folding of newly made subunits of the asialoglycoprotein receptor within the endoplasmic reticulum. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42340-x] [Citation(s) in RCA: 170] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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119
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Sandberg K, Ji H, Clark A, Shapira H, Catt K. Cloning and expression of a novel angiotensin II receptor subtype. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50109-0] [Citation(s) in RCA: 199] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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120
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Kurisu K, Ohsaki Y, Nagata K, Inai T, Kukita T. Heterogeneous distribution of the precursor of type I and type III collagen and fibronectin in the rough endoplasmic reticulum of palatal mesenchymal cells of the mouse embryo cultured in ascorbate-depleted medium. Cell Tissue Res 1992; 267:429-35. [PMID: 1571957 DOI: 10.1007/bf00319365] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In order to examine the intracellular distribution of precursors of type I and type III collagen and fibronectin in the palatal mesenchymal (MEPM) cells of the mouse embryo cultured under ascorbate-deficient conditions, immuno-electron-microscopic studies were carried out by use of affinity purified antibodies for these proteins. MEPM cells were obtained from the palatal shelves of 14-day-old mouse fetuses and cultured for 3-7 days in medium, either with or without 50 ng/dish/day ascorbic acid. Results obtained were as follows: (1) Although the rough endoplasmic reticulum (rER) of MEPM cells cultured for 5 days in ascorbate-supplemented medium was flattened, that in cells cultured in ascorbate-deficient medium had a distended or vesicular appearance. (2) Vesicular or distended rER showed heterogeneous staining for both type I and type III collagen, namely, some parts of rER showed positive staining for both types of collagen, while others showed negative staining. (3) Both type I and type III collagen showed codistribution in the same vesicular rER. (4) Vesicular rER showed negative or very faint labelling for fibronectin. These results may suggest regional differences in the function of rER.
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Affiliation(s)
- K Kurisu
- Second Department of Anatomy, Faculty of Dentistry, Kyushu University, Fukuoka, Japan
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121
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Miyazono K, Thyberg J, Heldin C. Retention of the transforming growth factor-beta 1 precursor in the Golgi complex in a latent endoglycosidase H-sensitive form. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42818-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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122
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Kaushansky K, Lopez JA, Brown CB. Role of carbohydrate modification in the production and secretion of human granulocyte macrophage colony-stimulating factor in genetically engineered and normal mesenchymal cells. Biochemistry 1992; 31:1881-6. [PMID: 1737041 DOI: 10.1021/bi00121a042] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Colony-stimulating factors (CSFs) are a group of acidic glycoproteins which stimulate the proliferation and differentiation of hematopoietic progenitor cells in vitro and stimulate hemopoiesis in vivo. Human GM-CSF contains two N-linked carbohydrate side chains of the complex acidic type and several sites of O-linked carbohydrate clustered on serine and threonine residues near the N-terminus of the molecule. Previous studies have failed to detect a significant functional role for the carbohydrate modification characteristic of human GM-CSF. Using permanent cell lines and transient expression systems which produce moderate to high levels of native or carbohydrate-deficient forms of the growth factor, the role of carbohydrate modification in the biosynthesis and secretion of GM-CSF was studied. Unlike a number of other secreted glycoproteins, the transient time and secretory efficiency of several carbohydrate-deficient mutants of GM-CSF are indistinguishable from those of the native growth factor in BHK, 293, COS, and ldlD cells. Furthermore, normal human endothelial cells and fibroblasts, which normally produce the growth factor, can synthesize and secrete GM-CSF that lacks all forms of carbohydrate modification. These studies help to point out the range of roles played by carbohydrate modification in the biosynthesis, assembly, and secretion of glycoprotein hormones.
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Affiliation(s)
- K Kaushansky
- Division of Hematology, University of Washington School of Medicine, Seattle 98195
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123
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Kuznetsov G, Brostrom M, Brostrom C. Demonstration of a calcium requirement for secretory protein processing and export. Differential effects of calcium and dithiothreitol. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50615-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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124
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Taub ME, Shen WC. Polarity in the transcytotic processing of apical and basal membrane-bound peroxidase-polylysine conjugates in MDCK cells. J Cell Physiol 1992; 150:283-90. [PMID: 1734033 DOI: 10.1002/jcp.1041500210] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A conjugate of horseradish peroxidase (HRP) to poly(L-lysine) (PLL) was used to characterize a non-lysosomal proteolytic compartment in the MDCK Strain I epithelial cell line. This compartment is expressed in a polar fashion, and is capable of degradation of the PLL moiety in the conjugate followed by release of HRP via a basal-to-apical, but not apical-to-basal, transcytotic pathway. This uptake, cleavage, and transport process appears to require approximately 2 hr, as there is a 2 hr lag-time between conjugate administration to the basal surface and HRP release to the apical medium. Monensin (10 microM) failed to inhibit this process, indicating that participation of the trans-Golgi network (TGN) in the trafficking of internalized conjugate is not the rate-determining step. Inhibition of HRP transport was found to be elicited by 50 micrograms/ml leupeptin, but only when applied to the basal surface. Brief trypsinization of either the basal or apical surfaces of cells preloaded with HRP conjugate showed no appreciable inhibitory effect on the apical release of HRP, indicating that an intracellular compartment rather than surface-bound enzymes is responsible for the degradation of the PLL moiety in the conjugate. Our results demonstrate the presence of an intracellular proteolytic compartment which is accessible in the basal-to-apical, but not apical-to-basal, transport pathway; and this compartment can be exploited for the transcytosis of membrane-bound molecules.
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Affiliation(s)
- M E Taub
- Department of Pharmaceutical Sciences, University of Southern California School of Pharmacy, Los Angeles 90033
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125
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Dynamics of the Interphase Golgi Apparatus in Mammalian Cells. ADVANCES IN MOLECULAR AND CELL BIOLOGY 1992. [DOI: 10.1016/s1569-2558(08)60178-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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126
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Lee AW. Signal transduction by the colony-stimulating factor-1 receptor; comparison to other receptor tyrosine kinases. CURRENT TOPICS IN CELLULAR REGULATION 1992; 32:73-181. [PMID: 1318184 DOI: 10.1016/b978-0-12-152832-4.50005-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- A W Lee
- Clinical Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892
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127
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Takami N, Oda K, Ikehara Y. Aberrant processing of alkaline phosphatase precursor caused by blocking the synthesis of glycosylphosphatidylinositol. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)48392-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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128
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Affiliation(s)
- F Wieland
- Institut für Biochemie I, Universität Heidelberg, Germany
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129
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Abstract
Considerable advances have been made in recent years in our understanding of the biochemistry of mucin-type glycoproteins. This class of compounds is characterized mainly by a high level of O-linked oligosaccharides. Initially, the glycoproteins were solely known as the major constituents of mucus. Recent studies have shown that mucins from the gastrointestinal tract, lungs, salivary glands, sweat glands, breast, and tumor cells are structurally related to high-molecular-weight glycoproteins, which are produced by epithelial cells as membrane proteins. During mucin synthesis, an orchestrated sequence of events results in giant molecules of Mr 4 to 6 x 10(6), which are stored in mucous granules until secretion. Once secreted, mucin forms a barrier, not only to protect the delicate epithelial cells against the extracellular environment, but also to select substances for binding and uptake by these epithelia. This review is designed to critically examine relations between structure and function of the different compounds categorized as mucin glycoproteins.
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Affiliation(s)
- G J Strous
- Laboratory of Cell Biology, University of Utrecht, The Netherlands
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130
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131
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Preuss D, Mulholland J, Kaiser CA, Orlean P, Albright C, Rose MD, Robbins PW, Botstein D. Structure of the yeast endoplasmic reticulum: localization of ER proteins using immunofluorescence and immunoelectron microscopy. Yeast 1991; 7:891-911. [PMID: 1803815 DOI: 10.1002/yea.320070902] [Citation(s) in RCA: 152] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The endoplasmic reticulum (ER) and other secretory compartments of Saccharomyces cerevisiae have biochemical functions that closely parallel those described in higher eukaryotic cells, yet the morphology of the yeast organelles is quite distinct. In order to associate ER functions with the corresponding cellular structures, we localized several proteins, each of which is expected to be associated with the ER on the basis of enzymatic activity, biological function, or oligosaccharide content. These marker proteins were visualized by immunofluorescence or immunoelectron microscopy, allowing definition of the S. cerevisiae ER structure, both in intact cells and at the ultrastructural level. Each marker protein was most abundant within the membranes that envelop the nucleus and several were also found in extensions of the ER that frequently juxtapose the plasma membrane. Double-labeling experiments were entirely consistent with the idea that the marker proteins reside within the same compartment. This analysis has permitted, for the first time, a detailed characterization of the ER morphology as yeast cells proceed through their growth and division cycles.
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Affiliation(s)
- D Preuss
- Department of Genetics, Stanford University Medical Center, CA 94305
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132
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Gliniak B, Kozak S, Jones R, Kabat D. Disulfide bonding controls the processing of retroviral envelope glycoproteins. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54452-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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133
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Myrset AH, Johnsen BR, Kulseth MA, Wassdal I, Helgeland L. Investigation of a possible correlation between rates of secretion and microsomal membrane association of plasma proteins synthesized by rat liver. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1070:229-36. [PMID: 1751530 DOI: 10.1016/0005-2736(91)90169-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The rates of secretion of complement C3, haptoglobin and plasminogen have been determined after pulse labelling with [3H]leucine, and compared to the secretion of prothrombin, albumin and transferrin investigated previously (Kvalvaag, A.H., Tollersrud, O.K. and Helgeland, L. (1988) Biochim. Biophys. Acta 937, 319-327). To study membrane association, rough microsomes were treated with increasing concentrations of saponin, sodium deoxycholate or Triton X-100. All six proteins were quantitated in the soluble and membrane fraction by enzyme immunoassays. At concentrations of saponin from 0.08% to 0.32%, each secretory protein showed a characteristic distribution, almost identical to that obtained with 0.05% sodium deoxycholate or 0.08% Triton X-100. Albumin and transferrin with half-times for secretion (t1/2) 30 and 75 min, respectively, are both almost exclusively found in the luminal fraction (greater than 95%). Prothrombin and plasminogen, which both show an intermediate t1/2 (approx. 55 min), are partially associated with the membranes, as only about 60% was released. Haptoglobin and complement C3 also show some association with the membranes (80-85% released). C3 is secreted at the same rate as prothrombin and plasminogen (t1/2 = 55 min), whereas haptoglobin is secreted more rapidly (t1/2 = 40 min). Accordingly, no correlation between kinetics of secretion and membrane association was demonstrated.
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Affiliation(s)
- A H Myrset
- Department of Biochemistry, University of Oslo, Norway
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134
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Melhus H, Nilsson T, Peterson PA, Rask L. Retinol-binding protein and transthyretin expressed in HeLa cells form a complex in the endoplasmic reticulum in both the absence and the presence of retinol. Exp Cell Res 1991; 197:119-24. [PMID: 1915658 DOI: 10.1016/0014-4827(91)90488-g] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To establish a suitable experimental system for studies of the interaction of retinol-binding protein (RBP) with transthyretin (TTR) we have expressed the corresponding cDNAs in HeLa cells. To investigate whether complex formation might occur already in the endoplasmic reticulum (ER), the C-terminal ER retention signal, KDEL, was attached to TTR. The tetrameric TTR-KDEL fusion protein was retained in the ER of HeLa cells. When RBP was co-expressed with TTR-KDEL, RBP was retained intracellularly. A cDNA-encoding purpurin, a protein which is 50% identical to RBP, was then expressed together with TTR-KDEL. Purpurin was not retained intracellularly and did not bind to TTR coupled to Sepharose. The effect of the vitamin A status on the secretion of TTR and RBP was examined. While TTR expressed alone was not retained intracellularly, TTR was retained in vitamin A-deficient cells when co-expressed with RBP. Addition of retinol stimulated rapid secretion of both proteins. These results demonstrate that TTR can form a complex with RBP in the ER. The data suggest that RBP and TTR are secreted as a complex.
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Affiliation(s)
- H Melhus
- Department of Cell Research, Uppsala University, Sweden
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135
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Ota Y, Asakura A, Matsuura Y, Kondo H, Hitoshio A, Iwane A, Tanaka T, Kikuchi M, Ikehara M. High-level secretion of the extracellular domain of the human growth hormone receptor using a baculovirus system. Gene 1991; 106:159-64. [PMID: 1937047 DOI: 10.1016/0378-1119(91)90195-h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A chemically synthesized gene (hGHR-ED) coding for the extracellular domain (ED) of the human growth hormone (hGH) receptor (hGHR) was inserted into the genome of Autographa californica nuclear polyhedrosis virus adjacent to the polyhedrin promoter. Spodoptera frugiperda cells infected with the recombinant virus secreted a protein with hGH-binding activity into the medium. The secreted 35-kDa protein was purified to near homogeneity. The purified protein exhibited a high binding affinity (Kd = 0.2-0.3 nM) to hGH. The highest cell production capability was estimated at more than 10-20 micrograms hGHR-ED/ml of culture. The inhibition of the hGHR-ED secretion by treatment with tunicamycin suggests that glycosylation is important for secretion.
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Affiliation(s)
- Y Ota
- Protein Engineering Research Institute, Osaka, Japan
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136
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Bibila TA, Flickinger MC. A model of interorganelle monoclonal antibody transport and secretion in mouse hybridoma cells. Biotechnol Bioeng 1991; 38:767-80. [DOI: 10.1002/bit.260380711] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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137
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Lodish H, Kong N. Cyclosporin A inhibits an initial step in folding of transferrin within the endoplasmic reticulum. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98546-7] [Citation(s) in RCA: 125] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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138
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Abstract
Several lines of investigation have shown that protein transport from the endoplasmic reticulum to the Golgi is more complex than previously imagined. Dynamic sorting of both membrane and soluble proteins is now believed to occur on the cis side of the Golgi apparatus with some proteins returning to the endoplasmic reticulum while others travel onwards.
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Affiliation(s)
- H R Pelham
- MRC Laboratory of Molecular Biology, Cambridge, UK
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139
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Geering K. The functional role of the beta-subunit in the maturation and intracellular transport of Na,K-ATPase. FEBS Lett 1991; 285:189-93. [PMID: 1649770 DOI: 10.1016/0014-5793(91)80801-9] [Citation(s) in RCA: 171] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The minimal functional enzyme unit of Na,K-ATPase consists of an alpha-beta complex. The alpha-subunit bears all functional domains of the enzyme and so far a regulatory role for the beta-subunit in the catalytic cycle has not been established. On the other hand, increasing experimental evidence suggests that the beta-subunit is an indispensable element for the structural and functional maturation of the enzyme as well as its intracellular transport to the plasma membrane. This brief review summarizes the experimental data supporting the hypothesis that assembly of the beta-subunit is needed for the alpha-subunit to acquire the correct, stable configuration necessary for the acquisition of functional properties and its exit from the ER.
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Affiliation(s)
- K Geering
- Institut de Pharmacologie et Toxicologie, Université de Lausanne, Switzerland
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140
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Watowich SS, Morimoto RI, Lamb RA. Flux of the paramyxovirus hemagglutinin-neuraminidase glycoprotein through the endoplasmic reticulum activates transcription of the GRP78-BiP gene. J Virol 1991; 65:3590-7. [PMID: 2041085 PMCID: PMC241361 DOI: 10.1128/jvi.65.7.3590-3597.1991] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The cellular glucose-regulated protein GRP78-BiP is a member of the HSP70 stress family of gene products, and the protein is a resident component of the endoplasmic reticulum, where it is thought to play a role in the folding and oligomerization of secretory and membrane-bound proteins. GRP78-BiP also binds to malfolded proteins, and this may be one mechanism for preventing their intracellular transport. An induction in synthesis of the GRP78-BiP protein occurs in cells infected with paramyxoviruses (R. W. Peluso, R. A. Lamb, and P. W. Choppin, Proc. Natl. Acad. Sci. USA 75:6120-6124, 1978). We have studied the expression and activity of the GRP78-BiP gene and synthesis of the GRP78-BiP protein during infection with the paramyxovirus simian virus 5 (SV5). We wished to identify the viral component capable of causing activation of GRP78-BiP since GRP78-BiP interacts specifically and transiently with the SV5 hemagglutinin-neuraminidase (HN) glycoprotein during HN folding (D. T. W. Ng, R. E. Randall, and R. A. Lamb, J. Cell Biol. 109:3273-3289, 1989). Expression of cDNAs of the SV5 wild-type HN glycoprotein and a mutant form of HN that is malfolded but not the SV5 F glycoprotein or SV5 cytoplasmic proteins P, V, and M caused increased amounts of GRP78-BiP mRNA to accumulate, as detected by nuclease S1 protection assays. As unfolded or malfolded forms of HN cannot be detected to accumulate during SV5 infection, the data suggest that the flux of HN through the ER in SV5-infected cells can cause activation of GRP78-BiP transcription.
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Affiliation(s)
- S S Watowich
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500
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141
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Kim P, Arvan P. Folding and assembly of newly synthesized thyroglobulin occurs in a pre-Golgi compartment. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98913-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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142
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Pulford DJ, Britton P. Intracellular processing of the porcine coronavirus transmissible gastroenteritis virus spike protein expressed by recombinant vaccinia virus. Virology 1991; 182:765-73. [PMID: 1850927 PMCID: PMC7131517 DOI: 10.1016/0042-6822(91)90617-k] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The Spike (S) protein from a virulent British field isolate of porcine transmissible gastroenteritis virus (TGEV) FS772/70 was constructed from cDNA and inserted into the vaccinia virus (VV) thymidine kinase gene locus under the control of the VV early/late gene P7.5k promoter. Recombinant S protein was synthesized as an endo-beta-N-acetylglucosaminidase H (Endo H)-sensitive glycoprotein with high mannose simple oligosaccharides (gp 190) that underwent post-translational modification to an Endo H-resistant glycoprotein with complex oligosaccharides (gp210). Immunofluorescence analysis demonstrated that the majority of recombinant S protein was retained at the Golgi but some S protein was expressed on the plasma membrane. Monoclonal antibodies (mAbs) raised against native S protein reacted with this recombinant S protein; also, mice infected with the recombinant vaccinia virus (rVV) expressing the S protein induced TGEV neutralizing antibodies. A truncated S protein (S delta) was also expressed in rVV-infected cells by introducing a deletion into the S protein cDNA that removed 292 amino acids from the C-terminus. The S delta protein (gp 170) was shown to be antigenically similar to TGEV S protein by immunofluorescence and immunoprecipitation tests but was retained in the endoplasmic reticulum and not expressed on the cell surface.
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Affiliation(s)
- D J Pulford
- Division of Molecular Biology, A.F.R.C., Institute for Animal Health, Compton Laboratory, Newbury, Berkshire, United Kingdom
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143
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Kodukula K, Micanovic R, Gerber L, Tamburrini M, Brink L, Udenfriend S. Biosynthesis of phosphatidylinositol glycan-anchored membrane proteins. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(20)64345-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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144
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Fyfe JC, Ramanujam KS, Ramaswamy K, Patterson DF, Seetharam B. Defective brush-border expression of intrinsic factor-cobalamin receptor in canine inherited intestinal cobalamin malabsorption. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(20)64349-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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145
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Mahuran DJ. The biochemistry of HEXA and HEXB gene mutations causing GM2 gangliosidosis. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1096:87-94. [PMID: 1825792 DOI: 10.1016/0925-4439(91)90044-a] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- D J Mahuran
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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146
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Lederkremer GZ, Lodish HF. An alternatively spliced miniexon alters the subcellular fate of the human asialoglycoprotein receptor H2 subunit. Endoplasmic reticulum retention and degradation or cell surface expression. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(17)35306-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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147
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Affiliation(s)
- S R Pfeffer
- Department of Biochemistry, Stanford University School of Medicine, CA 94305-5307
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148
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Glycosylation and structure of the yeast MF alpha 1 alpha-factor precursor is important for efficient transport through the secretory pathway. J Bacteriol 1991; 173:627-35. [PMID: 1987155 PMCID: PMC207053 DOI: 10.1128/jb.173.2.627-635.1991] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The MF alpha 1 gene encodes a precursor, prepro-alpha-factor, that undergoes several proteolytic processing steps within the classical secretory pathway to produce the mature peptide pheromone, alpha-factor. To investigate the role of structural features of the MF alpha 1 precursor in alpha-factor production, we analyzed the effect of mf alpha 1 mutations that alter precursor structure in a number of ways. These mutations resulted in decreased alpha-factor secretion and intracellular accumulation of pro-alpha-factor. With the exception of the mutant lacking all three N glycosylation sites, the pro-alpha-factor forms that accumulated were core glycosylated but had not yet undergone the addition of outer chain carbohydrate. The delay, therefore, occurred at a step prior to the first proteolytic processing step involved in maturation of the precursor and was probably due to inefficient endoplasmic reticulum-to-Golgi transport. Elimination of all three N-glycosylation sites caused a delay in disappearance of intracellular precursor, and alpha-factor secretion was also slowed. These data indicate that N glycosylation is important but not essential for transport of the precursor through the secretory pathway. The decreased alpha-factor secretion and increased precursor accumulation seen with many different structural changes of pro-alpha-factor indicate that the secretory pathway is extremely sensitive to changes in precursor structure. This sensitivity could cause inefficient secretion of heterologous proteins and hybrids between MF alpha 1 and heterologous proteins in yeast cells.
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149
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150
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Glycophospholipid membrane anchor attachment. Molecular analysis of the cleavage/attachment site. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(17)35308-5] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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