Glycosyl phosphatidylinositol membrane anchoring of melanotransferrin (p97): apical compartmentalization in intestinal epithelial cells

1993 ◽  
Vol 104 (4) ◽  
pp. 1155-1162
Author(s):  
R. Alemany ◽  
M.R. Vila ◽  
C. Franci ◽  
G. Egea ◽  
F.X. Real ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Iron Metabolism ◽  
Cell Transformation ◽  
Physiological Role ◽  
Kinetic Studies ◽  
Cell Types ◽  
Malignant Cell ◽  
Melanoma Cells ◽  
Glycosyl Phosphatidylinositol ◽  
Fetal Intestine

Melanotransferrin (p97) is an iron-binding membrane glycoprotein with 40% homology to transferrin and lactoferrin. It was first identified on the basis of its high level of expression in melanoma cells, as compared to normal melanocytes. It is also present in many cultured cell types. In normal tissues, p97 is expressed in fetal intestine, umbilical cord, sweat gland ducts and liver sinusoidal lining cells. Kinetic studies in melanoma cells have suggested that p97 plays a role in iron metabolism. We have examined expression of p97 in cell lines derived from human colorectal carcinomas which express a differentiated phenotype. When polarized, these cells showed a preferred apical distribution of p97, as demonstrated by immunohistochemistry, immune electron microscopy and domain-selective biotinylation. Correspondingly, p97 was only found on the apical brush border of epithelial cells in the fetal intestine. p97 was shown to be anchored to the membrane through a glycosyl phosphatidylinositol moiety by treatment with phophatidylinositol-specific phospholipase C (PI-PLC) and labeling with [14C]ethanolamine. These observations provide a basis for the elucidation of the physiological role of p97 in iron metabolism and its possible role in cell proliferation and malignant cell transformation.

scholarly journals MicroRNA profiling in BEAS-2B cells exposed to alpha radiation reveals potential biomarkers for malignant cellular transformation

2020 ◽  
Vol 9 (6) ◽  
pp. 834-844
Author(s):  
Xuhong Dang ◽  
Haipeng Lin ◽  
Youchen Li ◽  
Xiuli Guo ◽  
Yayi Yuan ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Epithelial Cells ◽  
Alpha Particle ◽  
Cell Transformation ◽  
Malignant Cell ◽  
Bronchial Epithelial Cells ◽  
Bronchial Epithelial ◽  
Radon Exposure ◽  
Particle Irradiation ◽  
Malignant Cell Transformation

Abstract The carcinogenicity of radon has been convincingly documented through epidemiological studies of underground miners. The risk of lung cancer from radon exposure is due to the continuous radioactive decay of this gas and subsequent emission of high-energy alpha decay particles. And the bronchial epithelial cells are the main targets of radon exposure. However, there is a lack of early warning indicators of lung cancer caused by radon in the physical examination of populations involved in occupations with higher exposure to radon. To assess the potential of a molecular-based marker approach for the early detection of human lung cancer induced by radon, human bronchial epithelial cell injury models induced by alpha-particle irradiation were constructed. The results of transwell migration assay, transwell invasion assay, and the expression of the epithelial–mesenchymal transition-related proteins showed that malignant cell transformation could be triggered by alpha irradiation. Potential microRNAs (miRNAs) (hsa-miR-3907, hsa-miR-6732-3p, hsa-miR-4788, hsa-miR-5001-5p, and hsa-miR-4257) were screened using miRNA chips in cell models. The pathway analyses of miRNAs selected using DIANA-miRPath v3.0 showed that miRNAs involved in malignant cell transformation were associated with cell adhesion molecules, extracellular matrix receptor interaction, and proteoglycans in cancer, among others, which are closely related to the occurrence and development of carcinogenesis. Reverse Transcription Quantitative Real-Time PCR (RT-qPCR) assay showed that five screened miRNAs were up-regulated in five lung cancer tissue samples. In conclusion, the results indicated that hsa-miR-3907, hsa-miR-6732-3p, hsa-miR-4788, hsa-miR-5001-5p, and hsa-miR-4257 may be potential early markers of the malignant transformation of bronchial epithelial cells induced by alpha-particle irradiation.

Chloride currents in primary cultures of rabbit proximal and distal convoluted tubules

1998 ◽  
Vol 275 (5) ◽  
pp. F651-F663 ◽  
Author(s):  
Isabelle Rubera ◽  
Michel Tauc ◽  
Michel Bidet ◽  
Chantal Poujeol ◽  
Béatrice Cuiller ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cultured Cells ◽  
Primary Cultures ◽  
Physiological Role ◽  
Cell Types ◽  
Patch Clamp Technique ◽  
Chloride Currents ◽  
Hypotonic Stress ◽  
Quantitative Measurements ◽  
Whole Cell Patch Clamp

Cl− conductances were studied in cultured rabbit proximal convoluted tubule (PCT) epithelial cells and compared with those measured in cultured distal bright convoluted tubule (DCTb) epithelial cells. Using the whole cell patch-clamp technique, three types of Cl− conductances were identified in DCTb cultured cells. These consisted of volume-sensitive, Ca2+-activated, and forskolin-activated Cl−currents. In PCT cultured cells, only volume-sensitive and Ca2+-activated Cl− currents were recorded. The characteristics of Ca2+-activated currents in PCT cells closely resembled those in DCTb cells. Volume-sensitive Cl− currents could be elicited both in PCT and in DCTb cells by hypotonic stress. The pharmacological profile of this conductance was established for both cell types. Forskolin activated a linear Cl− current in DCTb cells but not in PCT cells. This conductance was insensitive to DIDS and corresponds to cystic fibrosis transmembrane conductance regulator (CFTR)-like channels. Quantitative measurements of SPQ fluorescence showed that only the apical membrane of DCTb cells possessed a Cl− pathway that was sensitive to forskolin. RT-PCR experiments showed the presence of CFTR mRNA in both cultures, whereas immunostaining experiments revealed the expression of CFTR in DCTb cells only. The physiological role of the different types of channels is discussed.

scholarly journals Differential Regulation and Function of CD73, a Glycosyl-Phosphatidylinositol–linked 70-kD Adhesion Molecule, on Lymphocytes and Endothelial Cells

1997 ◽  
Vol 136 (2) ◽  
pp. 421-431 ◽  
Author(s):  
Laura Airas ◽  
Jussi Niemelä ◽  
Marko Salmi ◽  
Tarja Puurunen ◽  
David J. Smith ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tyrosine Phosphorylation ◽  
Vascular Endothelial Cells ◽  
Physiological Role ◽  
Lymphocyte Activation ◽  
Cell Types ◽  
Glycosyl Phosphatidylinositol ◽  
Surface Modulation ◽  
And Function ◽  
Different Cell Types

CD73, otherwise known as ecto-5′-nucleotidase, is a glycosyl-phosphatidylinositol–linked 70-kD molecule expressed on different cell types, including vascular endothelial cells (EC) and certain subtypes of lymphocytes. There is strong evidence for lymphocyte CD73 having a role in several immunological phenomena such as lymphocyte activation, proliferation, and adhesion to endothelium, but the physiological role of CD73 in other cell types is less clear. To compare the biological characteristics of CD73 in different cell types, we have studied the structure, function, and surface modulation of CD73 on lymphocytes and EC. CD73 molecules on lymphocytes are shed from the cell surface as a consequence of triggering with an antiCD73 mAb, mimicking ligand binding. In contrast, triggering of endothelial CD73 does not have any effect on its expression. Lymphocyte CD73 is susceptible to phosphatidylinositol phospholipase, whereas only a small portion of CD73 on EC could be removed by this enzyme. Furthermore, CD73 on EC was unable to deliver a tyrosine phosphorylation inducing signal upon mAb triggering, whereas triggering of lymphocyte CD73 can induce tyrosine phosphorylation. Despite the functional differences, CD73 molecules on lymphocytes and EC were practically identical structurally, when studied at the protein, mRNA, and cDNA level. Thus, CD73 is an interesting example of a molecule which lacks structural variants but yet has a wide diversity of biological functions. We suggest that the ligand- induced shedding of lymphocyte CD73 represents an important and novel means of controlling lymphocyte– EC interactions.

scholarly journals Knockout of the LRRC26 subunit reveals a primary role of LRRC26-containing BK channels in secretory epithelial cells

2017 ◽  
Vol 114 (18) ◽  
pp. E3739-E3747 ◽  
Author(s):  
Chengtao Yang ◽  
Vivian Gonzalez-Perez ◽  
Taro Mukaibo ◽  
James E. Melvin ◽  
Xiao-Ming Xia ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Physiological Role ◽  
Cell Types ◽  
Bk Channels ◽  
Specific Cell ◽  
Primary Role ◽  
Cellular Functions ◽  
Α Subunit ◽  
Voltage Dependent

Leucine-rich-repeat-containing protein 26 (LRRC26) is the regulatory γ1 subunit of Ca2+- and voltage-dependent BK-type K+ channels. BK channels that contain LRRC26 subunits are active near normal resting potentials even without Ca2+, suggesting they play unique physiological roles, likely limited to very specific cell types and cellular functions. By using Lrrc26 KO mice with a β-gal reporter, Lrrc26 promoter activity is found in secretory epithelial cells, especially acinar epithelial cells in lacrimal and salivary glands, and also goblet and Paneth cells in intestine and colon, although absent from neurons. We establish the presence of LRRC26 protein in eight secretory tissues or tissues with significant secretory epithelium and show that LRRC26 protein coassembles with the pore-forming BK α-subunit in at least three tissues: lacrimal gland, parotid gland, and colon. In lacrimal, parotid, and submandibular gland acinar cells, LRRC26 KO shifts BK gating to be like α-subunit-only BK channels. Finally, LRRC26 KO mimics the effect of SLO1/BK KO in reducing [K+] in saliva. LRRC26-containing BK channels are competent to contribute to resting K+ efflux at normal cell membrane potentials with resting cytosolic Ca2+ concentrations and likely play a critical physiological role in supporting normal secretory function in all secretory epithelial cells.

Effect of Calcium on the Growth and Differentiation of Cultured Rat Esophageal Epithelial Cells

1982 ◽  
Vol 40 ◽  
pp. 132-133
Author(s):  
W.T. Gunning ◽  
M.R. Marino ◽  
M.S. Babcock ◽  
G.D. Stoner
Keyword(s):  
Epithelial Cells ◽  
Cell Types ◽  
Replication Rate ◽  
Enzymatic Dissociation ◽  
Growth Assay ◽  
Epidermal Growth ◽  
Fetal Bovine ◽  
Esophageal Epithelial Cells ◽  
Cellular Replication

The role of calcium in modulating cellular replication and differentiation has been described for various cell types. In the present study, the effects of Ca++ on the growth and differentiation of cultured rat esophageal epithelial cells was investigated.Epithelial cells were isolated from esophagi taken from 8 week-old male CDF rats by the enzymatic dissociation method of Kaighn. The cells were cultured in PFMR-4 medium supplemented with 0.25 mg/ml dialyzed fetal bovine serum, 5 ng/ml epidermal growth factor, 10-6 M hydrocortisone 10-6 M phosphoethanolamine, 10-6 M ethanolamine, 5 pg/ml insulin, 5 ng/ml transferrin, 10 ng/ml cholera toxin and 50 ng/ml garamycin at 36.5°C in a humidified atmosphere of 3% CO2 in air. At weekly intervals, the cells were subcultured with a solution containing 1% polyvinylpyrrolidone, 0.01% EGTA, and 0.05% trypsin. After various passages, the replication rate of the cells in PFMR-4 medium containing from 10-6 M to 10-3 M Ca++ was determined using a clonal growth assay.

Membrane microdomains: lessons from microscopy

1995 ◽  
Vol 53 ◽  
pp. 776-777
Author(s):  
J.M. Robinson ◽  
J.M Oliver
Keyword(s):  
Spatial Distribution ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Plasma Membranes ◽  
Cell Types ◽  
Imaging Modalities ◽  
Membrane Microdomains ◽  
Membrane Domains ◽  
Lateral Heterogeneity ◽  
Functional Importance

Specialized regions of plasma membranes displaying lateral heterogeneity are the focus of this Symposium. Specialized membrane domains are known for certain cell types such as differentiated epithelial cells where lateral heterogeneity in lipids and proteins exists between the apical and basolateral portions of the plasma membrane. Lateral heterogeneity and the presence of microdomains in membranes that are uniform in appearance have been more difficult to establish. Nonetheless a number of studies have provided evidence for membrane microdomains and indicated a functional importance for these structures.This symposium will focus on the use of various imaging modalities and related approaches to define membrane microdomains in a number of cell types. The importance of existing as well as emerging imaging technologies for use in the elucidation of membrane microdomains will be highlighted. The organization of membrane microdomains in terms of dimensions and spatial distribution is of considerable interest and will be addressed in this Symposium.

scholarly journals The MAL Protein, an Integral Component of Specialized Membranes, in Normal Cells and Cancer

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1065
Author(s):  
Armando Rubio-Ramos ◽  
Leticia Labat-de-Hoz ◽  
Isabel Correas ◽  
Miguel A. Alonso
Keyword(s):  
Epithelial Cells ◽  
Large Body ◽  
Original Description ◽  
Cell Types ◽  
Future Research ◽  
Transmembrane Segments ◽  
Epsilon Toxin ◽  
Proteolipid Proteins ◽  
Polarized Epithelial Cells

The MAL gene encodes a 17-kDa protein containing four putative transmembrane segments whose expression is restricted to human T cells, polarized epithelial cells and myelin-forming cells. The MAL protein has two unusual biochemical features. First, it has lipid-like properties that qualify it as a member of the group of proteolipid proteins. Second, it partitions selectively into detergent-insoluble membranes, which are known to be enriched in condensed cell membranes, consistent with MAL being distributed in highly ordered membranes in the cell. Since its original description more than thirty years ago, a large body of evidence has accumulated supporting a role of MAL in specialized membranes in all the cell types in which it is expressed. Here, we review the structure, expression and biochemical characteristics of MAL, and discuss the association of MAL with raft membranes and the function of MAL in polarized epithelial cells, T lymphocytes, and myelin-forming cells. The evidence that MAL is a putative receptor of the epsilon toxin of Clostridium perfringens, the expression of MAL in lymphomas, the hypermethylation of the MAL gene and subsequent loss of MAL expression in carcinomas are also presented. We propose a model of MAL as the organizer of specialized condensed membranes to make them functional, discuss the role of MAL as a tumor suppressor in carcinomas, consider its potential use as a cancer biomarker, and summarize the directions for future research.

scholarly journals What Are the Potential Roles of Nuclear Perlecan and Other Heparan Sulphate Proteoglycans in the Normal and Malignant Phenotype

2021 ◽  
Vol 22 (9) ◽  
pp. 4415
Author(s):  
Anthony J. Hayes ◽  
James Melrose
Keyword(s):  
Gene Expression ◽  
Nuclear Envelope ◽  
Annulus Fibrosus ◽  
Heparan Sulphate ◽  
Cell Types ◽  
Malignant Cell ◽  
Cytoskeletal Proteins ◽  
Nucleus Pulposus Cells ◽  
Malignant Phenotype ◽  
Heparan Sulphate Proteoglycans

The recent discovery of nuclear and perinuclear perlecan in annulus fibrosus and nucleus pulposus cells and its known matrix stabilizing properties in tissues introduces the possibility that perlecan may also have intracellular stabilizing or regulatory roles through interactions with nuclear envelope or cytoskeletal proteins or roles in nucleosomal-chromatin organization that may regulate transcriptional factors and modulate gene expression. The nucleus is a mechano-sensor organelle, and sophisticated dynamic mechanoresponsive cytoskeletal and nuclear envelope components support and protect the nucleus, allowing it to perceive and respond to mechano-stimulation. This review speculates on the potential roles of perlecan in the nucleus based on what is already known about nuclear heparan sulphate proteoglycans. Perlecan is frequently found in the nuclei of tumour cells; however, its specific role in these diseased tissues is largely unknown. The aim of this review is to highlight probable roles for this intriguing interactive regulatory proteoglycan in the nucleus of normal and malignant cell types.

scholarly journals Homeostatic Functions of Tecrem, a CD46-Like Regulatory Protein of Complement Activation, on Epithelial Cells in Carp Fish

2021 ◽  
Vol 9 (7) ◽  
pp. 687
Author(s):  
Harsha Prakash ◽  
Shiori Motobe ◽  
Takahiro Nagasawa ◽  
Tomonori Somamoto ◽  
Miki Nakao
Keyword(s):  
Epithelial Cells ◽  
Regulatory Protein ◽  
Physiological Role ◽  
Aqueous Environment ◽  
Microbial Invasion ◽  
Epithelial Cell Lines ◽  
Expression Behavior ◽  
The Common ◽  
Ginbuna Crucian Carp ◽  
Junction Proteins

Fish mucosal surface is a significant interface for pathogens to infect from an aqueous environment. In addition to mucosal innate and adaptive immune factors, epithelial cells are considered as a significant physical barrier against microbial invasion. Previously, we identified a mammalian CD46-like complement regulatory protein (Tecrem) in teleost and detected its expression on epithelial cells derived from fin, suggesting its physiological role on the fish surface. This study examines the homeostatic roles of Tecrem in maintaining the fish epithelium, by analyzing the expression behavior of Tecrem on the fin-derived epithelial cell lines (KF-1 from the common carp and CFS from ginbuna crucian carp) using monoclonal and polyclonal anti-Tecrem antibodies. Expression of KF-1 protein was associated with the adhesion of KF-1, and the adhesion was enhanced by anti-Tecrem treatments of the cells. Stimulation of the epithelial cells with anti-Tecrem enhanced wound healing, protein expression of tight-junction proteins, and cell density of the KF-1 and CFS monolayer culture. These results suggest that Tecrem on epithelial cells play a homeostatic role in maintaining intactness of the surface epithelial barrier, implying that modification of Tecrem expression may develop a novel tool to improve the first-line defense against pathogens in aquaculture.

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