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Parnis S, Nicoletti C, Ollendorff V, Massey-Harroche D. Enterocytin: A new specific enterocyte marker bearing a B30.2-like domain. J Cell Physiol 2004; 198:441-51. [PMID: 14755549 DOI: 10.1002/jcp.10418] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Enterocyte differentiation is correlated to the expression of specific proteins which only a few of them are identified. In this study, we characterize a new marker of enterocyte differentiation using monoclonal antibodies. We showed that small intestinal enterocytes specifically express a new 47 kDa protein named Enterocytin. Expression of this protein increase along the crypt-villus axis and it is concentrated in the terminal web, lateral plasma membrane domain, and nucleus membrane of mature enterocytes. A 1.8-kb cDNA of Enterocytin was isolated by expression cloning from a cDNA library of rabbit small intestine. The amino acid sequence obtained shows an N-terminal region with a coiled-coil structure and a B30.2-like domain in the C-terminus region. By co-transfection and immunoprecipitation procedures on Cos cells, it was observed that the coiled-coil domain is involved in the homodimerization of Enterocytin. In the human intestine, a similar 47 kDa protein was detected, exclusively in the small intestinal enterocytes. In addition, expression of this protein in Caco2 cells is correlated with the state of differentiation of these cells. The restricted expression of Enterocytin in the intestine and its localization in mature cells suggest that it may contribute to the differentiation processes and maintenance of the enterocytic polarity.
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Affiliation(s)
- Stéphane Parnis
- Institut Méditerranéen de Recherche en Nutrition, Faculté des Sciences de Saint Jérôme, Avenue Escadrille Normandie-Niemen, Marseille cedex, France
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Schindler JF. Aminopeptidases function as endocytic receptors in the trophotaenial placenta of the goodeid fish, Ameca splendens (Teleostei: Atheriniformes). JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, COMPARATIVE EXPERIMENTAL BIOLOGY 2003; 299:213-22. [PMID: 12975809 DOI: 10.1002/jez.a.10282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Viviparity in goodeid teleosts is characterized by the elaboration of trophotaeniae, extraembryonic proctodaeal appendages facilitating maternal-embryonic nutrient transfer. The trophotaenial absorptive cells (TACs) express aminopeptidases (APs) such as APA, APN, gamma-glutamyltransferase (gamma-GT), dipeptidyl aminopeptidase (DAP) IV, and neutral endopeptidase (NEP) as inferred from the results of cleavage experiments with, respectively, Glu-alpha-(4M beta NA), Ala-(4M beta NA), Glu-gamma-(4M beta NA), Gly-Pro-(4M beta NA), and Gl-(Ala)(3)-(4M beta NA). Enzyme reaction product was localized to the apical and basolateral plasma membrane as well as to some intracellular compartments. In the accompanying report (Schindler, 2003) evidence is presented that the trophotaeniae of Ameca splendens embryos randomly, yet specifically, bind and ingest proteins as well as certain copolymers of amino acids. Present results demonstrate that endocytosis is significantly inhibitable by unspecific proteinase inhibitors, such as diisopropylphosphorofluoride, phenylmethanesulfonylfluoride, antipain, 1.10-phenanthroline, and dithiothreitol. The specific microbial AP inhibitors amastatin, bestatin, and phosphoramidon suppressed protein binding to TACs more effectively when added in combination than did either agent alone. Moreover, in the presence of 4M beta NA assay substrates of APs the capability of TACs to bind proteins was significantly reduced. Conversely, the rate at which 4M beta NA substrates were cleaved by trophotaenial APs was modified in the presence of proteins. Depending on protein concentrations the AP-catalyzed reactions either decreased or increased in velocity. Analysis of the enzyme kinetics by methods of linear transformation suggests that proteins bind to APs competitively, thereby adopting the role of enzyme inhibitors. On the other hand, protein binding to APs appears to be a signal to translocate enzymes from an internal pool to the surface membrane. In the presence of primaquine, the rate of AP-catalyzed cleavage of 4M beta NA substrates was significantly reduced. That can be put down to the fact that weak bases disrupt the recycling of endocytosed membrane constituents. In conclusion, there is evidence that APs in the trophotaenial placenta of A. splendens function as scavenger receptors mediating in the delivery of embryotrophic proteins for lysosomal degradation.
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Abstract
Transcytosis, the vesicular transport of macromolecules from one side of a cell to the other, is a strategy used by multicellular organisms to selectively move material between two environments without altering the unique compositions of those environments. In this review, we summarize our knowledge of the different cell types using transcytosis in vivo, the variety of cargo moved, and the diverse pathways for delivering that cargo. We evaluate in vitro models that are currently being used to study transcytosis. Caveolae-mediated transcytosis by endothelial cells that line the microvasculature and carry circulating plasma proteins to the interstitium is explained in more detail, as is clathrin-mediated transcytosis of IgA by epithelial cells of the digestive tract. The molecular basis of vesicle traffic is discussed, with emphasis on the gaps and uncertainties in our understanding of the molecules and mechanisms that regulate transcytosis. In our view there is still much to be learned about this fundamental process.
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Affiliation(s)
- Pamela L Tuma
- Hunterian 119, Department of Cell Biology, 725 N Wolfe St, Baltimore, MD 21205, USA
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Abstract
Absorptive cells are the main cells present in the intestinal epithelium. The plasma membrane of these tall columnar cells reflects their high degree of polarization, by dividing into apical and basolateral domains with different compositions. The most characteristic structure of these cells consists of closely packed apical microvilli with the same height, looking like a brush, which is why they were named the brush border. The concentrated pattern of some apical markers observed in a restricted brush border domain shows that mature enterocytes are hyperpolarized epithelial cells: the filamentous brush border glycocalyx is anchored at the top of the microvilli and the annexin XIII is concentrated in the lower three fourths. Many studies have been carried out on the biosynthesis and intracellular pathway of domain markers. The results show clearly that the basolateral markers take a direct pathway from the trans-Golgi network to the basolateral membrane. However, the two apical pathways, one direct and one indirect pathway via the basolateral membrane, are used, depending on the apical protein involved. Efficient protein sorting and addressing are essential to the establishment and maintenance of cell polarity, on which the integrity of the epithelial barrier depends.
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Affiliation(s)
- D Massey-Harroche
- Laboratoire de biologie et de biochimie de la nutrition, URA 1820, Faculté des Sciences de Saint Jérôme, Case 342, 13397, Marseille Cedex 20, France.
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Soubeyran P, André F, Lissitzky JC, Mallo GV, Moucadel V, Roccabianca M, Rechreche H, Marvaldi J, Dikic I, Dagorn JC, Iovanna JL. Cdx1 promotes differentiation in a rat intestinal epithelial cell line. Gastroenterology 1999; 117:1326-38. [PMID: 10579974 DOI: 10.1016/s0016-5085(99)70283-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Homeobox genes are involved in establishing and maintaining differentiated patterns in adult tissues. Cdx1 might carry out that function in the intestinal epithelium because its expression is specific to that tissue and increases during development. METHODS Cdx1 expression was induced in IEC-6 intestinal epithelial cells by stable transfection, and subsequent changes in cell growth, resistance to apoptosis, migration, and differentiation were monitored. RESULTS Compared with control, IEC-6/Cdx1 cells proliferated more rapidly, were more resistant to apoptosis, and migrated 3-4 times faster, as shown by an in vitro wound assay. IEC-6/Cdx1 cells in culture formed multilayers. Morphology of the top layer was similar to that of columnar epithelium, with cells showing typical features of differentiated enterocytes, including complex junctions and well-developed microvilli with glycocalix. Expression of 2 markers of enterocyte differentiation, aminopeptidase N and villin, was induced in IEC-6/Cdx1 cells. Aminopeptidase N was targeted to the basolateral membrane, and villin was localized to the cytoplasm. Actin filaments, which were mostly present in transcytoplasmic stress fibers in control cells, were redistributed to the cortex in Cdx1-transfected cells. CONCLUSIONS Cdx1 expression in IEC-6 cells induces phenotypic changes characteristic of differentiating enterocytes, suggesting an important role for Cdx1 in the transition from stem cells to proliferating/transit cells.
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Affiliation(s)
- P Soubeyran
- INSERM Unité 315, Laboratoire de Physiologie et Pathologie Digestives, Marseille, France
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Corbeil D, Röper K, Hannah MJ, Hellwig A, Huttner WB. Selective localization of the polytopic membrane protein prominin in microvilli of epithelial cells - a combination of apical sorting and retention in plasma membrane protrusions. J Cell Sci 1999; 112 ( Pt 7):1023-33. [PMID: 10198284 DOI: 10.1242/jcs.112.7.1023] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Prominin is a recently identified polytopic membrane protein expressed in various epithelial cells, where it is selectively associated with microvilli. When expressed in non-epithelial cells, prominin is enriched in plasma membrane protrusions. This raises the question of whether the selective association of prominin with microvilli in epithelial cells is solely due to its preference for, and stabilization in, plasma membrane protrusions, or is due to both sorting to the apical plasma membrane domain and subsequent enrichment in plasma membrane protrusions. To investigate this question, we have generated stably transfected MDCK cells expressing either full-length or C-terminally truncated forms of mouse prominin. Confocal immunofluorescence and domain-selective cell surface biotinylation experiments on transfected MDCK cells grown on permeable supports demonstrated the virtually exclusive apical localization of prominin at steady state. Pulse-chase experiments in combination with domain-selective cell surface biotinylation showed that newly synthesized prominin was directly targeted to the apical plasma membrane domain. Immunoelectron microscopy revealed that prominin was confined to microvilli rather than the planar region of the apical plasma membrane. Truncation of the cytoplasmic C-terminal tail of prominin impaired neither its apical cell surface expression nor its selective retention in microvilli. Both the apical-specific localization of prominin and its selective retention in microvilli were maintained when MDCK cells were cultured in low-calcium medium, i.e. in the absence of tight junctions. Taken together, our results show that: (i) prominin contains dual targeting information, for direct delivery to the apical plasma membrane domain and for the enrichment in the microvillar subdomain; and (ii) this dual targeting does not require the cytoplasmic C-terminal tail of prominin and still occurs in the absence of tight junctions. The latter observation suggests that entry into, and retention in, plasma membrane protrusions may play an important role in the establishment and maintenance of the apical-basal polarity of epithelial cells.
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Affiliation(s)
- D Corbeil
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Dresden, and Department of Neurobiology, University of Heidelberg, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany
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Massey-Harroche D, Mayran N, Maroux S. Polarized localizations of annexins I, II, VI and XIII in epithelial cells of intestinal, hepatic and pancreatic tissues. J Cell Sci 1998; 111 ( Pt 20):3007-15. [PMID: 9739074 DOI: 10.1242/jcs.111.20.3007] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The cellular and subcellular localizations of annexins I, II, VI and XIII in the rabbit intestine, liver and pancreas were studied by performing immunofluorescence labeling on thin frozen tissue sections using specific monoclonal antibodies. The expression of annexins was found to be finely regulated. Annexins XIII and I were expressed exclusively in the small intestine and the colon, respectively, whereas annexin II was present in all the tissues tested and annexin VI specifically in the liver and pancreas. These different annexins were concentrated in the basolateral domain of polarized cells, and some of them had an extra-apical localization: annexin XIII was concentrated in the lower 3/4 of enterocyte brush border microvilli; annexin II was present in the upper part of the terminal web in intestinal absorbent cells as well as in the bile canalicular area in hepatocytes, whereas annexin VI was detected on some apical vesicles concentrated around the bile canaliculi. In pancreatic acinar cells, the presence of annexin II on some zymogen granules provides further evidence that annexin II may be involved in exocytic events. In conclusion, this study shows that the basolateral domain of polarized cells appears to be the main site where annexins are located, and they may therefore be involved in the important cellular events occurring at this level.
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Affiliation(s)
- D Massey-Harroche
- Laboratoire de biologie et de biochimie de la nutrition, URA 1820, Faculté des Sciences de Saint Jérôme, Case 342, Marseille Cedex 20, France.
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Maury J, Bernadac A, Rigal A, Maroux S. Expression and glycosylation of the filamentous brush border glycocalyx (FBBG) during rabbit enterocyte differentiation along the crypt-villus axis. J Cell Sci 1995; 108 ( Pt 7):2705-13. [PMID: 7593311 DOI: 10.1242/jcs.108.7.2705] [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: 11/20/2022] Open
Abstract
The filamentous brush border glycocalyx forming the ‘enteric surface coat’ of the intestinal epithelium is composed in rabbits of a 400 kDa mucin-type glycoprotein, which was purified using the 3A4 monoclonal antibody. This monoclonal antibody recognizes a filamentous brush border glycocalyx-specific glycosidic structure containing an O-acetylated sialic acid, which is absent from all the other glycoproteins in the epithelium, with the exception of certain goblet cell mucins. Here we establish that only 50% of the rabbits tested synthesized this glycosidic structure. Upon immunolabeling surface epithelia and sections of jejunum from these rabbits, the carbohydrate epitope recognized by the 3A4 mAb was found to be present on the filamentous brush border glycocalyx of a variable number of enterocytes, which were patchily distributed over all the villi. This heterogeneous expression of 3A4 antigenicity, which was also observed in the crypts, suggests the existence of differences between the patterns of differentiation of enterocytes, which results in the expression of different pools of glycosyltransferases and/or acetyl transferases. In mature enterocytes, the 3A4 determinants were present only on the filamentous brush border glycocalyx, which is anchored solely to the membrane microdomain at the tip of brush border microvilli. However, expression of 3A4 antigenicity begins in the median third of crypts, in enterocytes with a short, thin brush border devoid of apical filamentous brush border glycocalyx. Here the 3A4 epitopes were present over the whole brush border membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Maury
- Laboratoire de Biochimie et Biologie de la Nutrition, CNRS-URA 1820, Faculté des Sciences de Saint Jéroôme, Marseille, France
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Maury J, Nicoletti C, Guzzo-Chambraud L, Maroux S. The filamentous brush border glycocalyx, a mucin-like marker of enterocyte hyper-polarization. ACTA ACUST UNITED AC 1995. [PMID: 7535695 DOI: 10.1111/j.1432-1033.1995.tb20267.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The probably sole constituent of the filamentous brush border glycocalyx, which has been defined on the basis of electron microscopic data as a set of filaments radiating from the tip of rabbit intestinal brush border microvilli, has been purified. It consists of a mucin-type glycoprotein that can be solubilized by either Triton extraction or papain treatment of the brush border membrane vesicles but is insensitive to phosphatidylinositol phospholipase C. The detergent- and papain-solubilized forms both have the same apparent molecular mass of 400 kDa (SDS/PAGE). This suggests that the filamentous brush border glycocalyx may be anchored to the membrane by a small hydrophobic peptidic tail. Ser, Thr, Pro and Ala amount to 65% of the protein core amino acid residues. The glycosidic moiety, which amounts to 73% of the molecular mass, has high O-acetylated sialic acid contents. A monoclonal antibody (3A4) raised against the purified material was produced which specifically recognized the 400-kDa band by immunoprecipitation and immunoblotting, and the filamentous brush border glycocalyx of villus enterocytes when jejunum sections were immunolabelled. The 3A4 determinant was identified with a filamentous brush border glycocalyx-specific carbohydrate structure containing an O-acetylated sialic acid. The fact that the labeled glycocalyx was anchored entirely in a membrane microdomain at the tip of the microvilli shows that mature enterocytes are hyper-polarized epithelial cells.
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Affiliation(s)
- J Maury
- Laboratoire de Biochimie et Biologie de la Nutrition, CNRS-URA 1820, Faculté des Sciences de Saint Jérôme, Marseille, France
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Lanctôt C, Fournier H, Howell S, Boileau G, Crine P. Direct targeting of neutral endopeptidase (EC 3.4.24.11) to the apical cell surface of transfected LLC-PK1 cells and unpolarized secretion of its soluble form. Biochem J 1995; 305 ( Pt 1):165-71. [PMID: 7826324 PMCID: PMC1136445 DOI: 10.1042/bj3050165] [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: 01/27/2023]
Abstract
LLC-PK1 cells were transfected with a cDNA encoding rabbit neutral endopeptidase (NEP; EC 3.4.24.11), an abundant enzyme of the kidney proximal brush border. Clones of cells expressing high levels of the protein were isolated. Selective biotinylation and radioimmunolabelling were used to determine that 85-95% of NEP was localized in the apical domain of filter-grown LLC-PK1 cells. Pulse-chase and selective biotinylation studies revealed that the majority (85%) of newly made NEP was directly targeted to the apical membrane. However, a soluble form of NEP was found to be secreted in approximately equal amounts from both sides of the monolayer when expressed in LLC-PK1 cells. Transfected pro-opiomelanocortin, a pituitary hormone precursor, was secreted almost exclusively into the basolateral medium, suggesting that the bulk flow is to the basolateral membrane. This behaviour contrasts with that observed in MDCK cells, where both the transmembrane and secreted forms of NEP are directly targeted to the apical membrane and where the secretion of pro-opiomelanocortin is unpolarized.
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Affiliation(s)
- C Lanctôt
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Québec, Canada
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Nicolas F, Tiveron MC, Davoust J, Reggio H. GPI membrane anchor is determinant in intracellular accumulation of apical plasma membrane proteins in the non-polarized human colon cancer cell line HT-29 18. J Cell Sci 1994; 107 ( Pt 10):2679-89. [PMID: 7876337 DOI: 10.1242/jcs.107.10.2679] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have compared the intracellular localization of plasma membrane proteins anchored either with a transmembrane segment or with a glycosylphosphatidylinositol moiety to estimate the effects of membrane anchor on protein segregation in the non-polarized form of the human colon cancer cell line HT-29 18. We have monitored two endogenous proteins: the carcinoembryonic antigen, a glycosylphosphatidylinositol protein and the transmembrane protein dipeptidyl peptidase IV, and two transfected proteins: the glycosylphosphatidylinositol protein Thy-1 and an engineered transmembrane form of Thy-1. Using immunocytochemistry on ultra-thin cryosections and confocal microscopy, we detected a carcinoembryonic antigen-rich vesicular compartment, excluding classical pre-lysosomal and lysosomal markers such as mannose 6-phosphate receptor, lamp-1 and cathepsin D. This compartment, where carcinoembryonic antigen accumulated, excluded the transmembrane protein dipeptidyl peptidase IV and was reduced during the polarization of the cells. Moreover, the glycosylphosphatidylinositol form of Thy-1 also accumulated in the carcinoembryonic antigen-rich compartment whereas the transmembrane form of Thy-1 was excluded. We proposed that, in the non-polarized HT-29 18 cells, accumulation of glycosylphosphatidylinositol proteins independently of transmembrane proteins reveals different intracellular fates for proteins according to their anchor in the plasma membrane.
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Affiliation(s)
- F Nicolas
- Laboratoire de Génétique et de Physiologie du Développement, UMR CNRS 9943, Faculté des Sciences de Luminy, Marseille, France
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O'Callaghan B, Synguelakis M, Le Gal la Salle G, Morel N. Characterization of aminopeptidase N from Torpedo marmorata kidney. Biol Cell 1994; 81:121-30. [PMID: 7849605 PMCID: PMC7131328 DOI: 10.1016/s0248-4900(94)80003-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A major antigen of the brush border membrane of Torpedo marmorata kidney was identified and purified by immunoprecipitation. The sequence of its 18 N terminal amino acids was determined and found to be very similar to that of mammalian amino-peptidase N (EC 3.4.11.2). Indeed aminopeptidase N activity was efficiently immunoprecipitated by monoclonal antibody 180K1. The purified antigen gives a broad band at 180 kDa after SDS-gel electrophoresis, which, after treatment by endoglycosidase F, is converted to a thinner band at 140 kDa. This antigen is therefore heavily glycosylated. Depending on solubilization conditions, both the antigen and peptidase activity were recovered either as a broad peak with a sedimentation coefficient of 18S (2% CHAPS) or as a single peak of 7.8S (1% CHAPS plus 0.2% C12E9), showing that Torpedo aminopeptidase N behaves as an oligomer stabilized by hydrophobic interactions, easily converted into a 160 kDa monomer. The antigen is highly concentrated in the apical membrane of proximal tubule epithelial cells (600 gold particles/microns2 of brush border membrane) whereas no labeling could be detected in other cell types or in other membranes of the same cells (basolateral membranes, vacuoles or vesicles). Monoclonal antibodies prepared here will be useful tools for further functional and structural studies of Torpedo kidney aminopeptidase N.
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Affiliation(s)
- B O'Callaghan
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, 91198 Gif-sur-Yvette, France
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Rémy L, Jacquier MF, Daémi N, Doré JF, Lissitzky JC. Comparative tumor morphogenesis of two human colon adenocarcinoma cell clones xenografted in the immunosuppressed newborn rat. Differentiation 1993; 54:191-200. [PMID: 7903648 DOI: 10.1111/j.1432-0436.1993.tb01601.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Two clones derived from the human adenocarcinoma cell line LoVo, E2 and C5 xenografted subcutaneously to immunosuppressed newborn rats, respectively produced well-differentiated and undifferentiated tumors. The comparative morphogenesis of these tumors was performed on xenografts explanted as early as 18 h and up to 21 days after grafting by studying the progressive setting of the enterocyte differentiation marker dipeptidylpeptidase IV, the basal lamina component laminin and the alpha 6 integrin subunit. E2 xenografts which were entirely undifferentiated 18 h after grafting, presented well-polarized acini-like tumoral islets 6 h later, i.e. only 1 day after injection. Basement membranes, which were not organized at this moment, may not be necessary for morphological polarization. The chronology of function antigens polarization was characterized by formation of a basement membrane 5 days after the graft with associated basal sorting of alpha 6 integrin. The polarization of alpha 6 integrin took, however, longer to be achieved while apical addressing of dipeptidylpeptidase IV was the last to be completed. In contrast, C5 tumors never differentiated. Even 21 days after grafting alpha 6 integrin remained pericellular, dipeptidylpeptidase IV was underexpressed and laminin was found as perilobular patches. Quantitative differences in laminin or alpha 6 integrin expression could not account for the differences in the polarization process observed in the two variants.
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Affiliation(s)
- L Rémy
- INSERM U 218, Centre Léon Bérard, Lyon, France
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Pinches SA, Gribble SM, Beechey RB, Ellis A, Shaw JM, Shirazi-Beechey SP. Preparation and characterization of basolateral membrane vesicles from pig and human colonocytes: the mechanism of glucose transport. Biochem J 1993; 294 ( Pt 2):529-34. [PMID: 8396917 PMCID: PMC1134487 DOI: 10.1042/bj2940529] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Membrane vesicles were isolated from the basolateral domains of pig and normal human colonocytes. The activity of the ouabain-sensitive K(+)-activated phosphatase, the basolateral membrane marker, was enriched 13-fold in these membrane vesicles over the original homogenate. The membranes displayed cross-reactions with antibodies to the (Na+/K+)ATPase and the RLA class I major histocompatibility antigen, both known indicators of the basolateral membrane. There was negligible contamination by other organelles and the luminal membrane, as revealed by marker-enzyme analysis and Western blotting, using an antibody to villin. The vesicles transported D-glucose in a cytochalasin B-inhibitable Na(+)-independent manner, with a Km of 28.1 +/- 0.8 mM and Vmax. of 3.1 +/- 0.4 nmol/s per mg of protein. The transport was inhibited by 2-deoxy-D-glucose and 3-O-methyl-D-glucose, but not by L-glucose or methyl-alpha-D-glucose. Probing the colonocyte basolateral membranes with an antibody against the C-terminus of the human liver GLUT 2 produced a cross-reaction at 52 kDa. These properties indicate the presence of a GLUT 2 isoform on the basolateral membranes of human and pig colonocytes.
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Affiliation(s)
- S A Pinches
- Department of Biochemistry, University of Wales, Aberystwyth, Dyfed, U.K
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Transepithelial Transport of Proteins by Intestinal Epithelial Cells. PHARMACEUTICAL BIOTECHNOLOGY 1993. [DOI: 10.1007/978-1-4615-2898-2_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
This chapter focuses on the interaction of viruses with epithelial cells. The role of specific pathways of virus entry and release in the pathogenesis of viral infection is examined together with the mechanisms utilized by viruses to circumvent the epithelial barrier. Polarized epithelial cells in culture, which can be grown on permeable supports, provide excellent systems for investigating the events in virus entry and release at the cellular level, and much information is being obtained using such systems. Much remains to be learned about the precise routes by which many viruses traverse the epithelial barrier to initiate their natural infection processes, although important information has been obtained in some systems. Another area of great interest for future investigation is the process of virus entry and release from other polarized cell types, including neuronal cells.
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Affiliation(s)
- S P Tucker
- Department of Microbiology, University of Alabama, Birmingham 35294
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17
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Quaroni A, Nichols BL, Quaroni E, Hurst K, Herrera L, Weiser MM, Hamilton SR. Expression and different polarity of aminopeptidase N in normal human colonic mucosa and colonic tumors. Int J Cancer 1992; 51:404-11. [PMID: 1375588 DOI: 10.1002/ijc.2910510312] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Expression and cellular localization of brush-border enzymes (aminopeptidase N, dipeptidylpeptidase IV, lactase, maltase) in normal human colon, colonic polyps and malignant intestinal tumors were investigated with a panel of monoclonal antibodies reacting with either native or denatured proteins. The enzymes were detected on cryostat sections by indirect immunofluorescence staining, or affinity-purified and analyzed by gel electrophoresis and immunoblotting. Dipeptidylpeptidase IV, lactase and maltase were absent from all samples examined, while aminopeptidase N (APN) was detected at the basal membrane of the epithelial cells in most specimens of colon obtained from individuals free of intestinal tumors. In contrast, APN was frequently localized at the luminal membrane of the surface epithelium in large-intestinal mucosa distal to tumors, adenomas and hyperplastic polyps, and from members of hereditary colon cancer syndrome families. APN was also expressed in colonic tumors, where it was present in an apical cell membrane location in 3/23 adenomas and 14/35 adenocarcinomas examined. No correlation was found between tumor-cell invasiveness (classified by "Dukes" stage) and expression or cellular location of aminopeptidase N. Histologically, all positive tumors were moderately or well differentiated. These results suggest that aminopeptidase N is normally expressed in adult human colon, but epithelial cells in the large and small intestine differ in their ways of sorting this enzyme intracellularly and eventually inserting it into different aspects of their surface membrane, a process which may be altered at an early stage of carcinogenesis.
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Affiliation(s)
- A Quaroni
- Section of Physiology, Cornell Univesity, Ithaca, NY 14853
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Saucan L, Palade GE. Differential colchicine effects on the transport of membrane and secretory proteins in rat hepatocytes in vivo: bipolar secretion of albumin. Hepatology 1992; 15:714-21. [PMID: 1551647 DOI: 10.1002/hep.1840150427] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We carried out a comparative investigation on the effects of colchicine (25 mumoles/100 gm body wt) on the intracellular transport, processing and discharge by secretion or proteolytic processing of a membrane protein (i.e., the polymeric IgA receptor) and a secretory protein (i.e., albumin) in rat hepatocytes. The results obtained indicated the following: (a) the transport and processing of polymeric IgA receptor is strongly inhibited and delayed, but the appearance of secretory component in the bile is not arrested; (b) polymeric IgA receptor reaches the sinusoidal plasmalemma in colchicine-treated specimens, as it does in controls; (c) albumin discharge into the plasma is strongly inhibited and markedly delayed in colchicine-treated as compared with control animals; (d) the reverse applies for albumin secretion in the bile, which is increased by a large factor; (e) newly synthesized albumin secreted directly from hepatocytes in control and in colchicine-treated animals is the major source of bile albumin; and (f) colchicine affects in different ways the polymeric IgA receptor and albumin arrival at the sinusoidal front and especially at the biliary front of the hepatocyte.
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Affiliation(s)
- L Saucan
- Division of Cellular and Molecular Medicine, University of California, San Diego, La Jolla 92093
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19
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Le Bivic A, Sambuy Y, Patzak A, Patil N, Chao M, Rodriguez-Boulan E. An internal deletion in the cytoplasmic tail reverses the apical localization of human NGF receptor in transfected MDCK cells. J Biophys Biochem Cytol 1991; 115:607-18. [PMID: 1655809 PMCID: PMC2289181 DOI: 10.1083/jcb.115.3.607] [Citation(s) in RCA: 133] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A cDNA encoding the full-length 75-kD human nerve growth factor receptor was transfected into MDCK cells and its product was found to be expressed predominantly (80%) on the apical membrane, as a result of vectorial targeting from an intracellular site. Apical hNGFR bound NGF with low affinity and internalized it inefficiently (6% of surface bound NGF per hour). Several mutant hNGFRs were analyzed, after transfection in MDCK cells, for polarized surface expression, ligand binding, and endocytosis. Deletionof juxta-membrane attachment sites for a cluster of O-linked sugars did not alter apical localization. A mutant receptor lacking the entire cytoplasmic tail (except for the five proximal amino acids) was also expressed on the apical membrane, suggesting that information for apical sorting was contained in the ectoplasmic or transmembrane domains. However, a 58 amino acid deletion in the hNGFR tail that moved a cytoplasmic tyrosine (Tyr 308) closer to the membrane into a more charged environment resulted in a basolateral distribution of the mutant receptor and reversed vectorial (basolateral) targeting. The basolateral mutant receptor also internalized 125I-NGF rapidly (90% of surface bound NGF per hour), exhibited a larger intracellular fraction and displayed a considerably shortened half-life (approximately 3 h). We suggest that hNGFR with the internal cytoplasmic deletion expresses a basolateral targeting signal, related to endocytic signals, that is dominant over apical targeting information in the ecto/transmembrane domains. These results apparently contradict a current model that postulates that basolateral targeting is a default mechanism.
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Affiliation(s)
- A Le Bivic
- Department of Cell Biology and Anatomy, Cornell University Medical College, New York, NY 10021
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20
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Neutral endopeptidase, a major brush border protein of the kidney proximal nephron, is directly targeted to the apical domain when expressed in Madin-Darby canine kidney cells. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)55066-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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21
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Involvement of both vectorial and transcytotic pathways in the preferential apical cell surface localization of rat dipeptidyl peptidase IV in transfected LLC-PK1 cells. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)55050-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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22
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Schaerer E, Neutra MR, Kraehenbuhl JP. Molecular and cellular mechanisms involved in transepithelial transport. J Membr Biol 1991; 123:93-103. [PMID: 1956074 DOI: 10.1007/bf01998081] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- E Schaerer
- Swiss Institute for Experimental Cancer Research, University of Lausanne, Epalinges
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23
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Gilbert T, Le Bivic A, Quaroni A, Rodriguez-Boulan E. Microtubular organization and its involvement in the biogenetic pathways of plasma membrane proteins in Caco-2 intestinal epithelial cells. J Cell Biol 1991; 113:275-88. [PMID: 1672691 PMCID: PMC2288937 DOI: 10.1083/jcb.113.2.275] [Citation(s) in RCA: 190] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We characterized the three-dimensional organization of microtubules in the human intestinal epithelial cell line Caco-2 by laser scanning confocal microscopy. Microtubules formed a dense network approximately 4-microns thick parallel to the cell surface in the apical pole and a loose network 1-micron thick in the basal pole. Between the apical and the basal bundles, microtubules run parallel to the major cell axis, concentrated in the vicinity of the lateral membrane. Colchicine treatment for 4 h depolymerized 99.4% of microtubular tubulin. Metabolic pulse chase, in combination with domain-selective biotinylation, immune and streptavidin precipitation was used to study the role of microtubules in the sorting and targeting of four apical and one basolateral markers. Apical proteins have been recently shown to use both direct and transcytotic (via the basolateral membrane) routes to the apical surface of Caco-2 cells. Colchicine treatment slowed down the transport to the cell surface of apical and basolateral proteins, but the effect on the apical proteins was much more drastic and affected both direct and indirect pathways. The final effect of microtubular disruption on the distribution of apical proteins depended on the degree of steady-state polarization of the individual markers in control cells. Aminopeptidase N (APN) and sucrase-isomaltase (SI), which normally reach a highly polarized distribution (110 and 75 times higher on the apical than on the basolateral side) were still relatively polarized (9 times) after colchicine treatment. The decrease in the polarity of APN and SI was mostly due to an increase in the residual basolateral expression (10% of control total surface expression) since 80% of the newly synthesized APN was still transported, although at a slower rate, to the apical surface in the absence of microtubules. Alkaline phosphatase and dipeptidylpeptidase IV, which normally reach only low levels of apical polarity (four times and six times after 20 h chase, nine times and eight times at steady state) did not polarize at all in the presence of colchicine due to slower delivery to the apical surface and increased residence time in the basolateral surface. Colchicine-treated cells displayed an ectopic localization of microvilli or other apical markers in the basolateral surface and large intracellular vacuoles. Polarized secretion into apical and basolateral media was also affected by microtubular disruption. Thus, an intact microtubular network facilitates apical protein transport to the cell surface of Caco-2 cells via direct and indirect routes; this role appears to be crucial for the final polarity of some apical plasma membrane proteins but only an enhancement factor for others.
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Affiliation(s)
- T Gilbert
- Department of Cell Biology and Anatomy, Cornell University Medical College, New York 10021
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24
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25
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Protein traffic between distinct plasma membrane domains: isolation and characterization of vesicular carriers involved in transcytosis. Cell 1991; 64:81-9. [PMID: 1986870 DOI: 10.1016/0092-8674(91)90210-p] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have isolated a population of vesicular carriers involved in the transport (transcytosis) of proteins from the basolateral to the apical plasma membrane of hepatocytes. The obtained fraction was enriched in compartments containing known transcytosed proteins and depleted in elements of the secretory pathway, Golgi elements, basolateral plasma membrane, as well as early endosomal components. The fraction was analyzed by biochemical and immunological procedures. Antibodies raised against the proteins in the fraction recognized a single 108K antigen. Based on its subcellular distribution, the 108K antigen may represent a novel marker for transcytotic vesicular carriers.
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26
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Abstract
The cell surface membrane is the boundary between a cell and its environment. In case of polarized epithelial cells, the apical plasma membrane is frequently the boundary between an organism and its environment. The plasmalemma possesses the elements that endow a cell with the capacity to converse with its environment. Plasmalemmal receptor and transducer proteins allow the cell to recognize and respond to various external influences. Membrane-associated proteins anchor cells to their substrata and mediate their integration into tissues. Many properties of a given cell type may be attributed to the protein composition of its plasma membrane. Most cells go to large lengths to control the nature and distribution of polypeptides that populate their plasmalemmas. Cells regulate the expression of genes encoding plasma membrane proteins. Proteins destined for the insertion into the plasma membrane pass through a complex system of processing organelles prior to arriving at their site of ultimate functional residence. Each of these organelles makes a unique contribution to the maturation of these proteins as they transit through them. This chapter discusses the postsynthetic steps involved in the biogenesis of plasma membrane proteins. The chapter discusses some of the events common to all plasmalemmal polypeptides, with special emphasis on those that contribute directly to the character of the cell surface. The chapter then discusses the specializations, associated with cell types, possessing differentiated cell surface sub-domains. The chapter highlights some of the important and fascinating questions confronting investigators interested in the cell biology of the plasma membrane.
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27
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Wessels HP, Hansen GH, Fuhrer C, Look AT, Sjöström H, Norén O, Spiess M. Aminopeptidase N is directly sorted to the apical domain in MDCK cells. J Cell Biol 1990; 111:2923-30. [PMID: 1980123 PMCID: PMC2116386 DOI: 10.1083/jcb.111.6.2923] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In different epithelial cell types, integral membrane proteins appear to follow different sorting pathways to the apical surface. In hepatocytes, several apical proteins were shown to be transported there indirectly via the basolateral membrane, whereas in MDCK cells a direct sorting pathway from the trans-Golgi-network to the apical membrane has been demonstrated. However, different proteins had been studied in these cells. To compare the sorting of a single protein in both systems, we have expressed aminopeptidase N, which already had been shown to be sorted indirectly in hepatocytes, in transfected MDCK cells. As expected, it was predominantly localized to the apical domain of the plasma membrane. By monitoring the appearance of newly synthesized aminopeptidase N at the apical and basolateral surface, it was found to be directly sorted to the apical domain in MDCK cells, indicating that the sorting pathways are indeed cell type-specific.
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Affiliation(s)
- H P Wessels
- Department of Biochemistry, University of Basel, Switzerland
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28
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Le Bivic A, Quaroni A, Nichols B, Rodriguez-Boulan E. Biogenetic pathways of plasma membrane proteins in Caco-2, a human intestinal epithelial cell line. J Cell Biol 1990; 111:1351-61. [PMID: 1976637 PMCID: PMC2116246 DOI: 10.1083/jcb.111.4.1351] [Citation(s) in RCA: 185] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We studied the sorting and surface delivery of three apical and three basolateral proteins in the polarized epithelial cell line Caco-2, using pulse-chase radiolabeling and surface domain-selective biotinylation (Le Bivic, A., F. X. Real, and E. Rodriguez-Boulan. 1989. Proc. Natl. Acad. Sci. USA. 86:9313-9317). While the basolateral proteins (antigen 525, HLA-I, and transferrin receptor) were targeted directly and efficiently to the basolateral membrane, the apical markers (sucrase-isomaltase [SI], aminopeptidase N [APN], and alkaline phosphatase [ALP]) reached the apical membrane by different routes. The large majority (80%) of newly synthesized ALP was directly targeted to the apical surface and the missorted basolateral pool was very inefficiently transcytosed. SI was more efficiently targeted to the apical membrane (greater than 90%) but, in contrast to ALP, the missorted basolateral pool was rapidly transcytosed. Surprisingly, a distinct peak of APN was detected on the basolateral domain before its accumulation in the apical membrane; this transient basolateral pool (at least 60-70% of the enzyme reaching the apical surface, as measured by continuous basal addition of antibodies) was efficiently transcytosed. In contrast with their transient basolateral expression, apical proteins were more stably localized on the apical surface, apparently because of their low endocytic capability in this membrane. Thus, compared with two other well-characterized epithelial models, MDCK cells and the hepatocyte, Caco-2 cells have an intermediate sorting phenotype, with apical proteins using both direct and indirect pathways, and basolateral proteins using only direct pathways, during biogenesis.
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Affiliation(s)
- A Le Bivic
- Department of Cell Biology and Anatomy, Cornell University Medical College, New York 10021
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29
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van 't Hof W, van Meer G. Generation of lipid polarity in intestinal epithelial (Caco-2) cells: sphingolipid synthesis in the Golgi complex and sorting before vesicular traffic to the plasma membrane. J Cell Biol 1990; 111:977-86. [PMID: 2391372 PMCID: PMC2116282 DOI: 10.1083/jcb.111.3.977] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Generation of intestinal epithelial lipid polarity was studied in Caco-2 cells. Confluent monolayers on filters incorporated the exchangeable lipid N-6-NBD-aminocaproyl-sphingosine (C6-NBD-ceramide) from liposomes. The fluorescent ceramide was converted equally to C6-NBD-glucosylceramide and C6-NBD-sphingomyelin, analogues of lipids enriched on the apical and basolateral surface, respectively, of intestinal cells in vivo. Below 16 degrees C, where vesicular traffic is essentially blocked, each fluorescent product accumulated in the Golgi area. At 37 degrees C, 50% had been transported to the cell surface within 0.5 h, as measured by selective extraction of the fluorescent lipids onto BSA in the medium ("back-exchange") at 10 degrees C. Transport to the two surfaces could be assayed separately, as a diffusion barrier existed for both NBD-lipids and BSA. C6-NBD-glucosylceramide was enriched twofold apically, whereas C6-NBD-sphingomyelin was equally distributed over both domains. Polarities did not decrease when 37 degrees C incubations were carried out in the presence of increasing BSA concentrations to trap the fluorescent lipids immediately after their arrival at the cell surface. Within 10 min from the start of synthesis, both products displayed their typical surface polarity. Lipid transcytosis displayed a half time of hours. In conclusion, newly synthesized sphingolipids in Caco-2 cells are sorted before reaching the cell surface. Transcytosis is not required for generating the in vivo lipid polarity.
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Affiliation(s)
- W van 't Hof
- Department of Cell Biology, Medical School, University of Utrecht, The Netherlands
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30
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Dyer J, Beechey RB, Gorvel JP, Smith RT, Wootton R, Shirazi-Beechey SP. Glycyl-L-proline transport in rabbit enterocyte basolateral-membrane vesicles. Biochem J 1990; 269:565-71. [PMID: 2167659 PMCID: PMC1131624 DOI: 10.1042/bj2690565] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The properties of a peptide-transport system in rabbit enterocyte basolateral membrane were examined with glycyl-L-proline as the substrate. Basolateral-membrane vesicles prepared from rabbit proximal intestine were characterized in terms of both purity and orientation. Marker-enzyme assays show that the basolateral-membrane marker, ouabain-sensitive K(+)-activated phosphatase, is enriched 17-fold with respect to the initial homogenate. The activities of enzymes used as markers for other membranes and organelles are low, and contamination of the final membrane fraction with these is minimal. The use of immunoblotting techniques further confirms the absence of brush-border-membrane contamination. Proteins in the basolateral-membrane vesicle preparation gave no cross-reaction with antibodies against the 140 kDa antigen and the Na+/glucose-symport protein, markers specific to the brush-border membrane of the enterocyte. Conversely, antibodies raised against the classical basolateral-membrane marker, the RLA class I histocompatibility complex, reacted strongly with a 43 kDa basolateral-membrane protein. The orientation of the basolateral-membrane vesicles was shown to be predominantly inside-out on determination by two independent criteria. The uptake of [1-14C]glycyl-L-proline by these vesicles is stimulated by the presence of an inwardly directed pH gradient, and this stimulation can be abolished by the proton ionophores carbonyl cyanide p-trichloromethoxyphenylhydrazone (CCCP) and tetrachlorotrifluoromethylbenzimidazole (TTFB). Transport is also inhibited by HgCl2, thimerosal, Na+ and other glycyl dipeptides.
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Affiliation(s)
- J Dyer
- Department of Biochemistry, University College of Wales, Aberystwyth, U.K
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31
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Casanova JE, Breitfeld PP, Ross SA, Mostov KE. Phosphorylation of the polymeric immunoglobulin receptor required for its efficient transcytosis. Science 1990; 248:742-5. [PMID: 2110383 DOI: 10.1126/science.2110383] [Citation(s) in RCA: 228] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The endosomal compartment of polarized epithelial cells is a major crossroads for membrane traffic. Proteins entering this compartment from the cell surface are sorted for transport to one of several destinations: recycling to the original cell surface, targeting to lysosomes for degradation, or transcytosis to the opposite surface. The polymeric immunoglobulin receptor (pIgR), which is normally transcytosed from the basolateral to the apical surface, was used as a model to dissect the signals that mediate this sorting event. When exogenous receptor was expressed in Madin-Darby Canine Kidney (MDCK) cells, it was shown that phosphorylation of pIgR at the serine residue at position 664 is required for efficient transcytosis. Replacement of this serine with alanine generated a receptor that is transcytosed only slowly, and appears to be recycled. Conversely, substitution with aspartic acid (which mimics the negative charge of the phosphate group) results in rapid transcytosis. It was concluded that phosphorylation is the signal that directs the pIgR from the endosome into the transcytotic pathway.
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Affiliation(s)
- J E Casanova
- Department of Anatomy, University of California, San Francisco 94143
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32
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Le Bivic A, Sambuy Y, Mostov K, Rodriguez-Boulan E. Vectorial targeting of an endogenous apical membrane sialoglycoprotein and uvomorulin in MDCK cells. J Biophys Biochem Cytol 1990; 110:1533-9. [PMID: 2335561 PMCID: PMC2200188 DOI: 10.1083/jcb.110.5.1533] [Citation(s) in RCA: 132] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We studied the cell-surface delivery pathways of newly synthesized membrane glycoproteins in MDCK cells and for this purpose we characterized an endogenous apical integral membrane glycoprotein. By combining a pulse-chase protocol with domain-selective cell-surface biotinylation, immune precipitation, and streptavidin-agarose precipitation (Le Bivic et al. 1989. Proc. Natl. Acad. Sci USA. 86:9313-9317), we followed the appearance at the cell surface of a major apical sialoglycoprotein, gp114, a basolateral protein, uvomorulin, and a transcytosing protein, the polyimmunoglobulin receptor (pIg-R). We determined that both gp114 and uvomorulin appeared to be delivered directly to their respective surface, with mistargeting levels of 8 and 2%, respectively. Using the same technique, the pIg-R was first detected on the basolateral domain and then on the apical domain, to be finally released into the apical medium, as described (Mostov, K. E., and D. L. Deitcher. 1986. Cell. 46:613-621). To directly determine whether the gp114 pool present on the basolateral surface was a precursor of the apical gp114, we compared it with the equivalent pIg-R pool, by labeling with sulfo-NHS-SS-biotin, a cleavable, tight junction-impermeable probe, and by following the fraction of this probe that became resistant to basal glutathione and accessible to apical glutathione during incubation at 37 degrees C. We found that, contrary to pIg-R, basolateral gp114 was poorly endocytosed and was not transcytosed to the apical side. These results demonstrate that an endogenous apical integral membrane glycoprotein of Madin-Darby canine kidney cells is sorted intracellularly and is vectorially targeted to the apical surface.
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Affiliation(s)
- A Le Bivic
- Department of Cell Biology and Anatomy, Cornell University Medical College, New York 10021
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33
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Schiechl H. N-terminal amino acid sequence, immunohistochemical localization and tissue distribution of a plasma membrane protein (Prot17) of rat enterocytes. HISTOCHEMISTRY 1990; 93:513-8. [PMID: 2332352 DOI: 10.1007/bf00266410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Prot17, a protein of the basolateral membrane of rat small intestine with a mol.wt. of 17 kDa, can be isolated using a previously described method (Schiechl 1988). It occurs in the membrane as an oligomer with a mol.wt. of 90 kDa. In the present study a polyclonal antibody specific for Prot17 was used to explore by immunohistochemical techniques the tissue distribution of Prot17 and its ultrastructural localization within the cells. Furthermore the amino acid sequence of the N-terminal part of this molecule up to position 17 could be analyzed. The results are summarized as follows: Prot17 is a membrane anchored protein. Its partial amino acid sequence suggests that it is neither identical nor related to other known proteins. Immunofluorescence studies revealed, that it occurs only in epithelial cells. It is mainly found in the absorptive and goblet cells of the intestine and the acinar cells of the pancreas. Smaller quantities are found also in the bile duct epithelium of the liver, in the proximal tubule cells of the kidney and in the cells of the respiratory epithelium. Ultrastructural localization of Prot17 was possible in the intestinal epithelium and pancreas acinar cells. In both cell types it was found in the basolateral and microvillous membrane. In pancreas, Prot17 was also detected in the membrane of the zymogen granules. In the absorptive cells of the intestine Prot17 was found in both the membrane and the contents of subluminal vesicles. Furthermore, in apical granules of secretory cells of the respiratory epithelium binding of Prot17 specific antibody was found in the granular content, the membrane being negative.
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Affiliation(s)
- H Schiechl
- Institut für Histologie und Embryologie, Universität Graz, Austria
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34
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Matter K, Brauchbar M, Bucher K, Hauri HP. Sorting of endogenous plasma membrane proteins occurs from two sites in cultured human intestinal epithelial cells (Caco-2). Cell 1990; 60:429-37. [PMID: 2302734 DOI: 10.1016/0092-8674(90)90594-5] [Citation(s) in RCA: 222] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We studied the postsynthetic sorting of endogenous plasma membrane proteins in a polarized epithelial cell line, Caco-2. Pulse-chase radiolabeling was combined with domain-specific cell surface assays to monitor the arrival of three apical and one basolateral protein at the apical and basolateral cell surface. Apical proteins were inserted simultaneously into both membrane domains. The fraction targeted to the basolateral domain was different for the three apical proteins and was subsequently sorted to the apical domain by transcytosis at different rates. In contrast, a basolateral protein was found in the basolateral membrane only. Thus, sorting of plasma membrane proteins occurred from two sites: the Golgi apparatus and the basolateral membrane. These data explain apparently conflicting results of earlier studies.
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Affiliation(s)
- K Matter
- Department of Pharmacology, University of Basel, Switzerland
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35
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Molitoris BA, Nelson WJ. Alterations in the establishment and maintenance of epithelial cell polarity as a basis for disease processes. J Clin Invest 1990; 85:3-9. [PMID: 2404027 PMCID: PMC296379 DOI: 10.1172/jci114427] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- B A Molitoris
- Department of Medicine, Veterans Administration Medical Center, Denver 80220
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36
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Graeve L, Drickamer K, Rodriguez-Boulan E. Polarized endocytosis by Madin-Darby canine kidney cells transfected with functional chicken liver glycoprotein receptor. J Cell Biol 1989; 109:2809-16. [PMID: 2687287 PMCID: PMC2115943 DOI: 10.1083/jcb.109.6.2809] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We have studied the expression of the chicken hepatic glycoprotein receptor (chicken hepatic lectin [CHL]) in Madin-Darby canine kidney (MDCK) cells, by transfection of its cDNA under the control of a retroviral promotor. Transfected cell lines stably express 87,000 surface receptors/cell with a kd = 13 nM. In confluent monolayers, approximately 40% of CHL is localized at the plasma membrane. 98% of the surface CHL is expressed at the basolateral surface where it performs polarized endocytosis and degradation of glycoproteins carrying terminal N-acetylglucosamine at a rate of 50,000 ligand molecules/h. Studies of the half-life of metabolically labeled receptor and of the stability of biotinylated cell surface receptor after internalization indicate that transfected CHL performs several rounds of uptake and recycling before it gets degraded. The successful expression of a functional basolateral receptor in MDCK cells opens the way for the characterization of the mechanisms that control targeting and recycling of proteins to the basolateral membrane of epithelial cells.
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Affiliation(s)
- L Graeve
- Department of Cell Biology and Anatomy, Cornell University Medical College, New York 10021
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37
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Trahair JF, Neutra MR, Gordon JI. Use of transgenic mice to study the routing of secretory proteins in intestinal epithelial cells: analysis of human growth hormone compartmentalization as a function of cell type and differentiation. J Biophys Biochem Cytol 1989; 109:3231-42. [PMID: 2689454 PMCID: PMC2115925 DOI: 10.1083/jcb.109.6.3231] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The intestinal epithelium is a heterogeneous cell monolayer that undergoes continuous renewal and differentiation along the crypt-villus axis. We have used transgenic mice to examine the compartmentalization of a regulated endocrine secretory protein, human growth hormone (hGH), in the four exocrine cells of the mouse intestinal epithelium (Paneth cells, intermediate cells, typical goblet cells, and granular goblet cells), as well as in its enteroendocrine and absorptive (enterocyte) cell populations. Nucleotides -596 to +21 of the rat liver fatty acid binding protein gene, when linked to the hGH gene (beginning at nucleotide +3) direct efficient synthesis of hGH in the gastrointestinal epithelium of transgenic animals (Sweetser, D. A., D. W. McKeel, E. F. Birkenmeier, P. C. Hoppe, and J. I. Gordon. 1988. Genes & Dev. 2:1318-1332). This provides a powerful in vivo model for analyzing protein sorting in diverse, differentiating, and polarized epithelial cells. Using EM immunocytochemical techniques, we demonstrated that this foreign polypeptide hormone entered the regulated basal granules of enteroendocrine cells as well as the apical secretory granules of exocrine Paneth cells, intermediate cells, and granular goblet cells. This suggests that common signals are recognized by the "sorting mechanisms" in regulated endocrine and exocrine cells. hGH was targeted to the electron-dense cores of secretory granules in granular goblet and intermediate cells, along with endogenous cell products. Thus, this polypeptide hormone contains domains that promote its segregation within certain exocrine granules. No expression of hGH was noted in typical goblet cells, suggesting that differences exist in the regulatory environments of granular and typical goblet cells. In enterocytes, hGH accumulated in dense-core granules located near apical and lateral cell surfaces, raising the possibility that these cells, which are known to conduct constitutive vesicular transport toward both apical and basolateral surfaces, also contain a previously unrecognized regulated pathway. Together our studies indicate that transgenic mice represent a valuable system for analyzing trafficking pathways and sorting mechanisms of secretory proteins in vivo.
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Affiliation(s)
- J F Trahair
- Department of Anatomy and Cellular Biology, Harvard Medical School, Boston, Massachusetts 02115
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Le Bivic A, Real FX, Rodriguez-Boulan E. Vectorial targeting of apical and basolateral plasma membrane proteins in a human adenocarcinoma epithelial cell line. Proc Natl Acad Sci U S A 1989; 86:9313-7. [PMID: 2687880 PMCID: PMC298485 DOI: 10.1073/pnas.86.23.9313] [Citation(s) in RCA: 170] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We studied the surface delivery pathways followed by newly synthesized plasma membrane proteins in intestinal cells. To this end, we developed an assay and characterized an epithelial cell line (SK-CO-15) derived from human colon adenocarcinoma. Polarized confluent monolayers (2000 omega.cm2), grown on polycarbonate filter chambers, were pulsed with radioactive methionine/cysteine and, at different times of chase, the protein fraction reaching the apical or basolateral surface was recovered by domain-selective biotinylation, immunoprecipitation, and immobilized streptavidin precipitation. Both an apical and a basolateral marker were found to be delivered vectorially to the respective surface, with a sorting efficiency of 50:1 for the basolateral marker and 14:1 for the apical marker.
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Affiliation(s)
- A Le Bivic
- Department of Cell Biology and Anatomy, Cornell University Medical College, New York, NY 10021
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Lisanti MP, Le Bivic A, Sargiacomo M, Rodriguez-Boulan E. Steady-state distribution and biogenesis of endogenous Madin-Darby canine kidney glycoproteins: evidence for intracellular sorting and polarized cell surface delivery. J Biophys Biochem Cytol 1989; 109:2117-27. [PMID: 2808522 PMCID: PMC2115858 DOI: 10.1083/jcb.109.5.2117] [Citation(s) in RCA: 141] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We used domain-selective biotinylation/125I-streptavidin blotting (Sargiacomo, M., M. P. Lisanti, L. Graeve, A. Le Bivic, and E. Rodriguez-Boulan. 1989 J. Membr. Biol. 107:277-286), in combination with lectin precipitation, to analyze the apical and basolateral glycoprotein composition of Madin-Darby canine kidney (MDCK) cells and to explore the role of glycosylation in the targeting of membrane glycoproteins. All six lectins used recognized both apical and basolateral glycoproteins, indicating that none of the sugar moieties detected were characteristic of the particular epithelial cell surface. Pulse-chase experiments coupled with domain-selective glycoprotein recovery were designed to detect the initial appearance of newly synthesized glycoproteins at the apical or basolateral cell surface. After a short pulse with a radioactive precursor, glycoproteins reaching each surface were biotinylated, extracted, and recovered via precipitation with immobilized streptavidin. Several basolateral glycoproteins (including two sulfated proteins) and at least two apical glycoproteins (one of them the major sulfated protein of MDCK cells) appeared at the corresponding surface after 20-40 min of chase, but were not detected in the opposite surface, suggesting that they were sorted intracellularly and vectorially delivered to their target membrane. Several "peripheral" apical proteins were detected at maximal levels on the apical surface immediately after the 15-min pulse, suggesting a very fast intracellular transit. Finally, domain-selective labeling of surface carbohydrates with biotin hydrazide (after periodate oxidation) revealed strikingly different integral and peripheral glycoprotein patterns, resembling the Con A pattern, after labeling with sulfo-N-hydroxy-succinimido-biotin. The approaches described here should be useful in characterizing the steady-state distribution and biogenesis of endogenous cell surface components in a variety of epithelial cell lines.
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Affiliation(s)
- M P Lisanti
- Department of Cell Biology and Anatomy, Cornell University Medical College, New York 10021
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Abstract
Polarized epithelial cells play fundamental roles in the ontogeny and function of a variety of tissues and organs in mammals. The morphogenesis of a sheet of polarized epithelial cells (the trophectoderm) is the first overt sign of cellular differentiation in early embryonic development. In the adult, polarized epithelial cells line all body cavities and occur in tissues that carry out specialized vectorial transport functions of absorption and secretion. The generation of this phenotype is a multistage process requiring extracellular cues and the reorganization of proteins in the cytoplasm and on the plasma membrane; once established, the phenotype is maintained by the segregation and retention of specific proteins and lipids in distinct apical and basal-lateral plasma membrane domains.
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Affiliation(s)
- E Rodriguez-Boulan
- Department of Cell Biology and Anatomy, Cornell University Medical College, New York, NY 10021
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41
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Cereijido M, Ponce A, Gonzalez-Mariscal L. Tight junctions and apical/basolateral polarity. J Membr Biol 1989. [DOI: 10.1007/bf01870987] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Gorvel JP, Mishal Z, Liegey F, Rigal A, Maroux S. Conformational change of rabbit aminopeptidase N into enterocyte plasma membrane domains analyzed by flow cytometry fluorescence energy transfer. J Cell Biol 1989; 108:2193-200. [PMID: 2472401 PMCID: PMC2115577 DOI: 10.1083/jcb.108.6.2193] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Membrane vesicle preparations are very appropriate material for studying the topology of glycoproteins integrated into specialized plasma membrane domains of polarized cells. Here we show that the flow cytometric measurement of fluorescence energy transfer used previously to study the relationship between surface components of isolated cells can be applied to membrane vesicles. The fluorescein and rhodamine derivatives of a monoclonal antibody (4H7.1) that recognized one common epitope of the rabbit and pig aminopeptidase N were used for probing the oligomerization and conformational states of the enzyme integrated into the brush border and basolateral membrane vesicles prepared from rabbit and pig enterocytes. The high fluorescent energy transfer observed in the case of pig enzyme integrated into both types of vesicles and in the case of the rabbit enzyme integrated into basolateral membrane vesicles agreed very well with the existence of a dimeric organization, which was directly demonstrated by cross-linking experiments. Although with the latter technique we observed that the rabbit aminopeptidase was also dimerized in the brush border membrane, no energy transfer was detected with the corresponding vesicles. This indicates that the relative positions of two associated monomers differ depending on whether the rabbit aminopeptidase is transiently integrated into the basolateral membrane or permanently integrated into the brush border membrane. Cross-linking of aminopeptidases solubilized by detergent and of their ectodomains liberated by trypsin showed that only interactions between anchor domains maintained the dimeric structure of rabbit enzyme whereas interactions between ectodomains also exist in the pig enzyme. This might explain why the noticeable change in the organization of the two ectodomains observed in the case of rabbit aminopeptidase N does not occur in the case of pig enzyme.
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Affiliation(s)
- J P Gorvel
- Centre de Biochimie et de Biologie Moléculaire, Centre National de la Recherche Scientifique, Marseille, France
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Eilers U, Klumperman J, Hauri HP. Nocodazole, a microtubule-active drug, interferes with apical protein delivery in cultured intestinal epithelial cells (Caco-2). J Cell Biol 1989; 108:13-22. [PMID: 2642910 PMCID: PMC2115365 DOI: 10.1083/jcb.108.1.13] [Citation(s) in RCA: 149] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The polarized delivery of membrane proteins to the cell surface and the initial secretion of lysosomal proteins into the culture medium were studied in the polarized human intestinal adenocarcinoma cell line Caco-2 in the presence or absence of the microtubule-active drug nocodazole. The appearance of newly synthesized proteins at the plasma membrane was measured by their sensitivity to proteases added either to the apical or the basolateral surface of cells grown on nitrocellulose filters. Nocodazole was found to reduce the delivery to the cell surface of an apical membrane protein, aminopeptidase N, and to lead to its partial missorting to the basolateral surface, whereas the drug had no influence on the delivery of a basolateral 120-kD membrane protein defined by a monoclonal antibody. Furthermore, nocodazole selectively blocked the apical secretion of two lysosomal proteins, cathepsin D and acid alpha-glucosidase, whereas the drug had no influence on their basolateral secretion. These results suggest that in Caco-2 cells an intact microtubular network is important for the transport of newly synthesized proteins to the apical cell surface.
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Affiliation(s)
- U Eilers
- Department of Pharmacology, Biocenter of the University of Basel, Switzerland
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Maroux S, Coudrier E, Feracci H, Gorvel JP, Louvard D. Molecular organization of the intestinal brush border. Biochimie 1988; 70:1297-306. [PMID: 3147722 DOI: 10.1016/0300-9084(88)90198-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The brush border of enterocytes represents one of the more specialized apical poles of epithelial cells. It is formed by particularly well-developed apical plasma membrane microvilli, whose shape is ensured by a highly organized cytoskeleton. The molecular organization of the cytoskeleton is described. Whereas several cytoskeleton proteins are ubiquitous, villin is highly specific for intestinal cells and can be used as a differentiation marker of these cells. The major glycoproteins, in particular hydrolases, of the brush border membrane have been characterized. They have many common structural features, in particular their mode of integration into the membrane by their N-terminal hydrophobic sequences that also plays the role of the 'signal peptide' responsible for their co-translational insertions into the endoplasmic reticulum. Studies on the biosynthesis and intracellular pathway of aminopeptidase N strongly suggest that sorting of apical and basolateral glycoproteins could occur after their integration into the basolateral domain.
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Rindler MJ, Traber MG. A specific sorting signal is not required for the polarized secretion of newly synthesized proteins from cultured intestinal epithelial cells. J Cell Biol 1988; 107:471-9. [PMID: 2458357 PMCID: PMC2115219 DOI: 10.1083/jcb.107.2.471] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Caco-2 cells, derived from human colon, have the morphological, functional, and biochemical properties of small intestinal epithelial cells. After infection with enveloped viruses, influenza virions assembled at the apical plasma membrane while vesicular stomatitis virus (VSV) particles appeared exclusively at the basolateral membrane, similar to the pattern observed in virus-infected Madin-Darby canine kidney (MDCK). When grown in Millicell filter chamber devices and labeled with [35S]methionine, Caco-2 monolayers released all of their radiolabeled secretory products preferentially into the basal chamber. Among the proteins identified were apolipoproteins AI and E, transferrin, and alpha-fetoprotein. No proteins were observed to be secreted preferentially from the apical cell surface. The lysosomal enzyme beta-hexosaminidase was also secreted primarily from the basolateral surface of the cells in the presence or absence of lysosomotropic drugs or tunicamycin, which inhibit the targetting of lysosomal enzymes to lysosomes. Neither of these drug treatments significantly affected the polarized secretion of other nonlysosomal proteins. In addition, growth hormone (GH), which is released in a nonpolar fashion from MDCK cells, was secreted exclusively from the basolateral membrane after transfection of Caco-2 cells with GH cDNA in a pSV2-based expression vector. Similar results were obtained in transient expression experiments and after selection of permanently transformed Caco-2 cells expressing GH. Since both beta-hexosaminidase and GH would be expected to lack sorting signals for polarized exocytosis in epithelial cells, these results indicate that in intestinal cells, proteins transported via the basolateral secretory pathway need not have specific sorting signals.
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Affiliation(s)
- M J Rindler
- Department of Cell Biology, New York University Medical Center, New York 10016
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Bartles JR, Hubbard AL. Plasma membrane protein sorting in epithelial cells: do secretory pathways hold the key? Trends Biochem Sci 1988; 13:181-4. [PMID: 3255200 DOI: 10.1016/0968-0004(88)90147-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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