Transverse pattern of microfilament bundles induced in epitheliocytes by cylindrical substrata

Cylindrical culture substrata are known to induced longitudinal orientation of polarized fibroblasts and corresponding alignment of actin microfilament bundles in these cells. We studied microfilament bundle distribution in two cell types, fibroblasts and epitheliocytes, spread on two kinds of anisotropic substrata, quartz glass cylinders with a diameter 32 microns and narrow (25-40 microns wide) flat glass adhesive strips with non-adhesive borders. Rat embryo and human diploid fibroblasts, as expected, formed predominantly longitudinally aligned bundles on both substrata. In contrast, transverse bundles on cylinders and randomly oriented bundles on flat strips were formed in IAR-2 and MDCK epithelial cells. We interpret these data as showing that the epitheliocyte attempts to override the guiding influence of anisotropic substrata. The microfilament bundle pattern on cylinders depends on the integrity of the microtubules. Colcemid-induced microtubule depolymerization caused formation of longitudinal as well as transverse bundles both in fibroblasts and epitheliocytes, thus diminishing the differences in microfilament bundle patterns in two cell types. These results show that microtubules control the cell-type-specific distribution of microfilament bundles both in polarized fibroblasts and in discoid epitheliocytes. However, the results of this control are opposite: microtubules enhance cell polarization in fibroblasts, but prevent it in epithelial cells.

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Composition and function of PDZ protein complexes during cell polarization

AJP Renal Physiology ◽

10.1152/ajprenal.00086.2003 ◽

2003 ◽

Vol 285 (3) ◽

pp. F377-F387 ◽

Cited By ~ 88

Author(s):

Michael H. Roh ◽

Ben Margolis

Keyword(s):

Epithelial Cells ◽

Current Knowledge ◽

Protein Complexes ◽

Cell Types ◽

Cell Polarization ◽

Differential Distribution ◽

Pdz Proteins ◽

Homologous Protein ◽

Pdz Protein ◽

And Function

Complexes consisting of PDZ proteins have been implicated in a variety of cellular processes. In recent years, it has become increasingly clear that PDZ proteins play essential roles during the establishment of spatial asymmetry in various metazoan cell types such as epithelial cells. Epithelial cells possess asymmetry with respect to the apicobasal axis reflected by the differential distribution of proteins and lipids in the apical and basolateral surfaces. In Drosophila, three PDZ protein complexes have been shown to play crucial functions during the establishment of cell-cell adhesions and epithelial cell polarity: Bazooka/Dm-Par6/DaPKC, Crumbs/Stardust/Discs Lost, and Scribble/Discs Large/Lethal Giant Larvae. In this review, we focus primarily on our current knowledge of the localization and function of these complexes in Drosophila epithelia. We also discuss recent data that enhance our understanding of the homologous protein complexes and their roles during junctional assembly and polarization of mammalian epithelial cells.

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Polarization and Myelination in Myelinating Glia

ISRN Neurology ◽

10.5402/2012/769412 ◽

2012 ◽

Vol 2012 ◽

pp. 1-28 ◽

Cited By ~ 12

Author(s):

Toshihiro Masaki

Keyword(s):

Nervous System ◽

Epithelial Cells ◽

Schwann Cells ◽

Myelin Sheath ◽

Nerve Impulse ◽

Membrane System ◽

Cell Types ◽

Cell Polarization ◽

Polarization Study ◽

Myelinating Glia

Myelinating glia, oligodendrocytes in central nervous system and Schwann cells in peripheral nervous system, form myelin sheath, a multilayered membrane system around axons enabling salutatory nerve impulse conduction and maintaining axonal integrity. Myelin sheath is a polarized structure localized in the axonal side and therefore is supposed to be formed based on the preceding polarization of myelinating glia. Thus, myelination process is closely associated with polarization of myelinating glia. However, cell polarization has been less extensively studied in myelinating glia than other cell types such as epithelial cells. The ultimate goal of this paper is to provide insights for the field of myelination research by applying the information obtained in polarity study in other cell types, especially epithelial cells, to cell polarization of myelinating glia. Thus, in this paper, the main aspects of cell polarization study in general are summarized. Then, they will be compared with polarization in oligodendrocytes. Finally, the achievements obtained in polarization study for epithelial cells, oligodendrocytes, and other types of cells will be translated into polarization/myelination process by Schwann cells. Then, based on this model, the perspectives in the study of Schwann cell polarization/myelination will be discussed.

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SNARE expression and localization in renal epithelial cells suggest mechanism for variability of trafficking phenotypes

AJP Renal Physiology ◽

10.1152/ajprenal.00185.2002 ◽

2002 ◽

Vol 283 (5) ◽

pp. F1111-F1122 ◽

Cited By ~ 50

Author(s):

Xin Li ◽

Seng Hui Low ◽

Masumi Miura ◽

Thomas Weimbs

Keyword(s):

Epithelial Cells ◽

Membrane Trafficking ◽

Mdck Cells ◽

Cell Types ◽

Intercalated Cells ◽

Cell Type ◽

Specific Distribution ◽

Protein Receptors ◽

Syntaxin 4

The apical- and basolateral-specific distribution of target soluble N-ethylmaleimide-sensitive factor attachment protein receptors (t-SNAREs) of the syntaxin family appear to be critical for polarity in epithelial cells. To test whether differential SNARE expression and/or subcellular localization may contribute to the known diversity of trafficking phenotypes of epithelial cell types in vivo, we have investigated the distribution of syntaxins 2, 3, and 4 in epithelial cells along the renal tubule. Syntaxins 3 and 4 are restricted to the apical and basolateral domains, respectively, in all cell types, indicating that their mutually exclusive localizations are important for cell polarity. The expression level of syntaxin 3 is highly variable, depending on the cell type, suggesting that it is regulated in concert with the cellular requirement for apical exocytic pathways. While syntaxin 4 localizes all along the basal and lateral plasma membrane domains in vivo, it is restricted to the lateral membrane in Madin-Darby canine kidney (MDCK) cells in two-dimensional monolayer culture. When cultured as cysts in collagen, however, MDCK cells target syntaxin 4 correctly to the basal and lateral membranes. Unexpectedly, the polarity of syntaxin 2 is inverted between different tubule cell types, suggesting a role in establishing plasticity of targeting. The vesicle-associated (v)-SNARE endobrevin is highly expressed in intercalated cells and colocalizes with the H+-ATPase in α- but not β-intercalated cells, suggesting its involvement in H+-ATPase trafficking in the former cell type. These results suggest that epithelial membrane trafficking phenotypes in vivo are highly variable and that different cell types express or localize SNARE proteins differentially as a mechanism to achieve this variability.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053383 ◽

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.

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Membrane microdomains: lessons from microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100140257 ◽

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.

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

Cells ◽

10.3390/cells10051065 ◽

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.

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Urine-Derived Epithelial Cells as Models for Genetic Kidney Diseases

Cells ◽

10.3390/cells10061413 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1413

Author(s):

Tjessa Bondue ◽

Fanny O. Arcolino ◽

Koenraad R. P. Veys ◽

Oyindamola C. Adebayo ◽

Elena Levtchenko ◽

...

Keyword(s):

Epithelial Cells ◽

Kidney Diseases ◽

Cell Types ◽

Cell Models ◽

Tubular Epithelial Cells ◽

Disease Mechanisms ◽

Proximal Tubular Epithelial Cells ◽

Proximal Tubular ◽

Disease Cell

Epithelial cells exfoliated in human urine can include cells anywhere from the urinary tract and kidneys; however, podocytes and proximal tubular epithelial cells (PTECs) are by far the most relevant cell types for the study of genetic kidney diseases. When maintained in vitro, they have been proven extremely valuable for discovering disease mechanisms and for the development of new therapies. Furthermore, cultured patient cells can individually represent their human sources and their specific variants for personalized medicine studies, which are recently gaining much interest. In this review, we summarize the methodology for establishing human podocyte and PTEC cell lines from urine and highlight their importance as kidney disease cell models. We explore the well-established and recent techniques of cell isolation, quantification, immortalization and characterization, and we describe their current and future applications.

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Differential expression of ORCC and CFTR induced by low temperature in CF airway epithelial cells

AJP Cell Physiology ◽

10.1152/ajpcell.1995.268.1.c243 ◽

1995 ◽

Vol 268 (1) ◽

pp. C243-C251 ◽

Cited By ~ 37

Author(s):

M. E. Egan ◽

E. M. Schwiebert ◽

W. B. Guggino

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Incubation Temperature ◽

Cell Types ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Channel Activity ◽

Patch Clamp Recording ◽

Cl Channel ◽

Channel Expression

When nonepithelial cell types expressing the delta F508-cystic fibrosis transmembrane conductance regulator (CFTR) mutation are grown at reduced temperatures, the mutant protein can be properly processed. The effect of low temperatures on Cl- channel activity in airway epithelial cells that endogenously express the delta F508-CFTR mutation has not been investigated. Therefore, we examined the effect of incubation temperature on both CFTR and outwardly rectifying Cl- channel (ORCC) activity in normal, in cystic fibrosis (CF)-affected, and in wild-type CFTR-complemented CF airway epithelia with use of a combination of inside-out and whole cell patch-clamp recording, 36Cl- efflux assays, and immunocytochemistry. We report that incubation of CF-affected airway epithelial cells at 25-27 degrees C is associated with the appearance of a protein kinase A-stimulated CFTR-like Cl- conductance. In addition to the appearance of CFTR Cl- channel activity, there is, however, a decrease in the number of active ORCC when cells are grown at 25-27 degrees C, suggesting that the decrease in incubation temperature may be associated with multiple alterations in ion channel expression and/or regulation in airway epithelial cells.

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EEA1, a Tethering Protein of the Early Sorting Endosome, Shows a Polarized Distribution in Hippocampal Neurons, Epithelial Cells, and Fibroblasts

Molecular Biology of the Cell ◽

10.1091/mbc.11.8.2657 ◽

2000 ◽

Vol 11 (8) ◽

pp. 2657-2671 ◽

Cited By ~ 117

Author(s):

Jean M. Wilson ◽

Meltsje de Hoop ◽

Natasha Zorzi ◽

Ban-Hock Toh ◽

Carlos G. Dotti ◽

...

Keyword(s):

Epithelial Cells ◽

Mammalian Cells ◽

Hippocampal Neurons ◽

Cell Types ◽

Early Endosomes ◽

Filamentous Material ◽

Endocytic Vesicles ◽

Fibroblastic Cells ◽

Darby Canine Kidney ◽

Endocytic Pathways

EEA1 is an early endosomal Rab5 effector protein that has been implicated in the docking of incoming endocytic vesicles before fusion with early endosomes. Because of the presence of complex endosomal pathways in polarized and nonpolarized cells, we have examined the distribution of EEA1 in diverse cell types. Ultrastructural analysis demonstrates that EEA1 is present on a subdomain of the early sorting endosome but not on clathrin-coated vesicles, consistent with a role in providing directionality to early endosomal fusion. Furthermore, EEA1 is associated with filamentous material that extends from the cytoplasmic surface of the endosomal domain, which is also consistent with a tethering/docking role for EEA1. In polarized cells (Madin-Darby canine kidney cells and hippocampal neurons), EEA1 is present on a subset of “basolateral-type” endosomal compartments, suggesting that EEA1 regulates specific endocytic pathways. In both epithelial cells and fibroblastic cells, EEA1 and a transfected apical endosomal marker, endotubin, label distinct endosomal populations. Hence, there are at least two distinct sets of early endosomes in polarized and nonpolarized mammalian cells. EEA1 could provide specificity and directionality to fusion events occurring in a subset of these endosomes in polarized and nonpolarized cells.

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