The Molecular Physiology of Tight Junction Pores

Physiology ◽  
2004 ◽  
Vol 19 (6) ◽  
pp. 331-338 ◽  
Author(s):  
Christina M. Van Itallie ◽  
James Melvin Anderson
Keyword(s):  
Cell Adhesion ◽  
Caenorhabditis Elegans ◽  
Tight Junction ◽  
Electrical Resistance ◽  
Large Family ◽  
Paracellular Transport ◽  
Molecular Physiology ◽  
Ionic Charge ◽  
Charge Selectivity ◽  
Cell Adhesion Proteins

Tight junctions form selective barriers that regulate paracellular transport across epithelia. A large family of tetraspanning cell-cell adhesion proteins called claudins create the barrier and regulate electrical resistance, size, and ionic charge selectivity. Study of inherited human claudin diseases and the outcome of the genetic manupulation of claudins in mice, Drosophila, and Caenorhabditis elegans are furthering our understanding of paracellular physiology.

Claudins create charge-selective channels in the paracellular pathway between epithelial cells

2002 ◽  
Vol 283 (1) ◽  
pp. C142-C147 ◽  
Author(s):  
Oscar R. Colegio ◽  
Christina M. Van Itallie ◽  
Heather J. McCrea ◽  
Christoph Rahner ◽  
James Melvin Anderson
Keyword(s):  
Electrical Resistance ◽  
Freeze Fracture ◽  
Extracellular Domain ◽  
Inducible Promoter ◽  
Site Directed Mutagenesis ◽  
Solute Flux ◽  
Ionic Charge ◽  
Cell Monolayers ◽  
Charge Selectivity ◽  
Freeze Fracture Electron Microscopy

Epithelia separate tissue spaces by regulating the passage of ions, solutes, and water through both the transcellular and paracellular pathways. Paracellular permeability is defined by intercellular tight junctions, which vary widely among tissues with respect to solute flux, electrical resistance, and ionic charge selectivity. To test the hypothesis that members of the claudin family of tight junction proteins create charge selectivity, we assessed the effect of reversing the charge of selected extracellular amino acids in two claudins using site-directed mutagenesis. Claudins were expressed in cultured Madin-Darby canine kidney cell monolayers under an inducible promoter, and clones were compared with and without induction for transmonolayer electrical resistance and dilution potentials. Expression and localization of claudins were determined by immunoblotting, immunofluorescence microscopy, and freeze-fracture electron microscopy. We observed that substituting a negative for a positive charge at position 65 in the first extracellular domain of claudin-4 increased paracellular Na+ permeability. Conversely, substituting positive for negative charges at three positions in the first extracellular domain of claudin-15, singly and in combination, reversed paracellular charge selectivity from a preference for Na+ to Cl−. These results support a model where claudins create charge-selective channels in the paracellular space.

Claudins at the gate: determinants of renal epithelial tight junction paracellular permeability

2006 ◽  
Vol 290 (3) ◽  
pp. F572-F579 ◽  
Author(s):  
Daniel F. Balkovetz
Keyword(s):  
Tight Junction ◽  
Membrane Lipids ◽  
Expression Patterns ◽  
Large Family ◽  
Paracellular Permeability ◽  
Paracellular Transport ◽  
Renal Epithelial Cell ◽  
Culture Models ◽  
Epithelial Tight Junction ◽  
Renal Tubular

The epithelial tight junction (TJ) is responsible for the control of paracellular transport between epithelial cells (gate function) and the maintenance of apical/basolateral polarity by preventing the diffusion of membrane lipids and/or proteins from one surface domain to another (fence function). Renal tubule epithelia in the mammalian nephron have TJs that determine paracellular transport characteristics. Paracellular transport across renal tubular epithelial TJs (gate function) varies in different segments of the nephron. A large family of recently identified TJ-associated transmembrane proteins named claudins appear to determine the paracellular permeability properties of the TJ. A combination of inherited human diseases, renal epithelial cell culture models, and nephron expression patterns of claudins is providing important clues about how claudin molecules determine the TJ gate function of renal epithelia in different segments of the nephron.

scholarly journals Structure-Based Virtual Screening Allows the Identification of Efficient Modulators of E-Cadherin-Mediated Cell–Cell Adhesion

2019 ◽  
Vol 20 (14) ◽  
pp. 3404 ◽  
Author(s):  
Andrea Dalle Vedove ◽  
Federico Falchi ◽  
Stefano Donini ◽  
Aurelie Dobric ◽  
Sebastien Germain ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Virtual Screening ◽  
Adherens Junction ◽  
Large Family ◽  
Calcium Dependent ◽  
Molecule Inhibitor ◽  
Dependent Cell ◽  
Cell Adhesion Proteins ◽  
E Cadherin ◽  
Cell Cell

Cadherins are a large family of transmembrane calcium-dependent cell adhesion proteins that orchestrate adherens junction formation and are crucially involved in tissue morphogenesis. Due to their important role in cancer development and metastasis, cadherins can be considered attractive targets for drug discovery. A recent crystal structure of the complex of a cadherin extracellular portion and a small molecule inhibitor allowed the identification of a druggable interface, thus providing a viable strategy for the design of cadherin dimerization modulators. Here, we report on a structure-based virtual screening approach that led to the identification of efficient and selective modulators of E-cadherin-mediated cell–cell adhesion. Of all the putative inhibitors that were identified and experimentally tested by cell adhesion assays using human pancreatic tumor BxPC-3 cells expressing both E-cadherin and P-cadherin, two compounds turned out to be effective in inhibiting stable cell–cell adhesion at micromolar concentrations. Moreover, at the same concentrations, one of them also showed anti-invasive properties in cell invasion assays. These results will allow further development of novel and selective cadherin-mediated cell–cell adhesion modulators for the treatment of a variety of cadherin-expressing solid tumors and for improving the efficiency of drug delivery across biological barriers.

scholarly journals A Putative Catenin–Cadherin System Mediates Morphogenesis of the Caenorhabditis elegans Embryo

1998 ◽  
Vol 141 (1) ◽  
pp. 297-308 ◽  
Author(s):  
Michael Costa ◽  
William Raich ◽  
Cristina Agbunag ◽  
Ben Leung ◽  
Jeff Hardin ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Caenorhabditis Elegans ◽  
Cell Shape ◽  
Shape Change ◽  
Adherens Junctions ◽  
The Body ◽  
C Elegans ◽  
Cell Shape Change ◽  
Filament Bundles ◽  
Cell Adhesion Proteins

During morphogenesis of the Caenorhabditis elegans embryo, hypodermal (or epidermal) cells migrate to enclose the embryo in an epithelium and, subsequently, change shape coordinately to elongate the body (Priess, J.R., and D.I. Hirsh. 1986. Dev. Biol. 117:156– 173; Williams-Masson, E.M., A.N. Malik, and J. Hardin. 1997. Development [Camb.]. 124:2889–2901). We have isolated mutants defective in morphogenesis that identify three genes required for both cell migration during body enclosure and cell shape change during body elongation. Analyses of hmp-1, hmp-2, and hmr-1 mutants suggest that products of these genes anchor contractile actin filament bundles at the adherens junctions between hypodermal cells and, thereby, transmit the force of bundle contraction into cell shape change. The protein products of all three genes localize to hypodermal adherens junctions in embryos. The sequences of the predicted HMP-1, HMP-2, and HMR-1 proteins are related to the cell adhesion proteins α-catenin, β-catenin/Armadillo, and classical cadherin, respectively. This putative catenin–cadherin system is not essential for general cell adhesion in the C. elegans embryo, but rather mediates specific aspects of morphogenetic cell shape change and cytoskeletal organization.

Claudin Tight Junction Proteins: Novel Aspects in Paracellular Transport

2008 ◽  
Vol 28 (6) ◽  
pp. 577-584 ◽  
Author(s):  
Constanze Will ◽  
Michael Fromm ◽  
Dominik Müller
Keyword(s):  
Tight Junction ◽  
Solute Transport ◽  
Molecular Mechanisms ◽  
Family Members ◽  
Transport Processes ◽  
Paracellular Transport ◽  
Solute Flux ◽  
Solute Fluxes ◽  
Essential Components ◽  
Renal Tubular

Claudins are essential components of the intercellular tight junction and major determinants of paracellular solute fluxes across epithelia and endothelia. Many members of this family display a distinct charge or size specificity, whereas others render the epithelium impermeable to transport. Due to intercellular localization, claudin-mediated transport processes are passive and driven by an electrochemical gradient. In epithelial tissues, claudins exhibit a temporal–spatial expression pattern corresponding with regional and local solute transport profiles. Whereas paracellular transport mechanisms in organs such as intestine and kidney have been extensively investigated, little is known about the molecular mechanisms determining solute transport in the peritoneum, and thus the determinants of peritoneal dialysis. Given the ubiquitous expression of claudins in endothelia and epithelia, it is predictable that claudins also contribute to pore formation and determination in the peritoneum, and that they are involved in solute flux. Therefore, we review the basic characteristics of claudin family members and their function as exemplified in renal tubular transport and give an outlook to what extent claudin family members might be of importance for solute reabsorption across the peritoneal membrane.

Tc8, a Tourist-like Transposon in Caenorhabditis elegans

Genetics ◽  
2001 ◽  
Vol 158 (3) ◽  
pp. 1081-1088 ◽  
Author(s):  
Quang Hien Le ◽  
Kime Turcotte ◽  
Thomas Bureau
Keyword(s):  
Caenorhabditis Elegans ◽  
Expressed Sequence Tags ◽  
Large Family ◽  
Insertion Sequences ◽  
Normal Plant ◽  
Nematode Caenorhabditis Elegans ◽  
Plant Genomes ◽  
Plant Genes ◽  
Expressed Sequence ◽  
Eukaryotic Genomes

Abstract Members of the Tourist family of miniature inverted-repeat transposable elements (MITEs) are very abundant among a wide variety of plants, are frequently found associated with normal plant genes, and thus are thought to be important players in the organization and evolution of plant genomes. In Arabidopsis, the recent discovery of a Tourist member harboring a putative transposase has shed new light on the mobility and evolution of MITEs. Here, we analyze a family of Tourist transposons endogenous to the genome of the nematode Caenorhabditis elegans (Bristol N2). One member of this large family is 7568 bp in length, harbors an ORF similar to the putative Tourist transposase from Arabidopsis, and is related to the IS5 family of bacterial insertion sequences (IS). Using database searches, we found expressed sequence tags (ESTs) similar to the putative Tourist transposases in plants, insects, and vertebrates. Taken together, our data suggest that Tourist-like and IS5-like transposons form a superfamily of potentially active elements ubiquitous to prokaryotic and eukaryotic genomes.

Initial Attachment of MC3T3-E1 Cells on Nano-HAp Surfaces

2007 ◽  
Vol 361-363 ◽  
pp. 1115-1118
Author(s):  
Un Hye Kwon ◽  
Jung Suk Han ◽  
In Young Ryu ◽  
Dae Joon Kim
Keyword(s):  
Surface Roughness ◽  
Cell Adhesion ◽  
Fluorescence Microscopy ◽  
Cell Morphology ◽  
Confocal Laser ◽  
Initial Attachment ◽  
Zirconia Ceramics ◽  
Initial Cell ◽  
Cell Adhesion Proteins ◽  
Initial Cell Adhesion

The initial osteoblast like cell response to bioactive nano-sized hydroxyapatite (HAp) and bioinert zirconia was evaluated with the cell morphology by SEM and cell adhesion proteins by fluorescence microscopy. Surface roughness also measured by a confocal laser microscopy. The surface roughness and topography was almost identical among specimens. The nano-sized HAp specimens showed better initial cell adhesion and activity than bioinert zirconia ceramics.

scholarly journals Claudin-4 augments alveolar epithelial barrier function and is induced in acute lung injury

2009 ◽  
Vol 297 (2) ◽  
pp. L219-L227 ◽  
Author(s):  
Charlie Wray ◽  
Ying Mao ◽  
Jue Pan ◽  
Anita Chandrasena ◽  
Frank Piasta ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Tight Junction ◽  
Pulmonary Edema ◽  
Barrier Function ◽  
Mapk Pathway ◽  
Paracellular Transport ◽  
Epithelial Barrier ◽  
Altered Expression ◽  
Alveolar Epithelial

Intact alveolar barrier function is associated with better outcomes in acute lung injury patients; however, the regulation of alveolar epithelial paracellular transport during lung injury has not been extensively investigated. This study was undertaken to determine whether changes in tight junction claudin expression affect alveolar epithelial barrier properties and to determine the mechanisms of altered expression. In anesthetized mice exposed to ventilator-induced lung injury, claudin-4 was specifically induced among tight junction structural proteins. Real-time PCR showed an eightfold increase in claudin-4 expression in the lung injury model. To examine the role of this protein in barrier regulation, claudin-4 function was inhibited with small interfering RNA (siRNA) and a blocking peptide derived from the binding domain of Clostridium perfringens enterotoxin (CPEBD). Inhibition of claudin-4 decreased transepithelial electrical resistance but did not alter macromolecule permeability in primary rat and human epithelial cells. In mice, CPEBD decreased air space fluid clearance >33% and resulted in pulmonary edema during moderate tidal volume ventilation that did not induce edema in control peptide-treated mice. In vitro phorbol ester induced a ninefold increase in claudin-4 expression that was dependent on PKC activation and the JNK MAPK pathway. These data establish that changes in alveolar epithelial claudin expression influence paracellular transport, alveolar fluid clearance rates, and susceptibility to pulmonary edema. We hypothesize that increased claudin-4 expression early in acute lung injury represents a mechanism to limit pulmonary edema and that the regulation of alveolar epithelial claudin expression may be a novel target for acute lung injury therapy.

Stage-specific patterns of collagen gene expression during development of Caenorhabditis elegans

1985 ◽  
Vol 5 (2) ◽  
pp. 363-372
Author(s):  
G N Cox ◽  
D Hirsh
Keyword(s):  
Caenorhabditis Elegans ◽  
Protein Composition ◽  
Large Family ◽  
Major Protein ◽  
Mrna Levels ◽  
Mrna Accumulation ◽  
C Elegans ◽  
Collagen Protein ◽  
Protein Components ◽  
Collagen Genes

Collagens are the major protein components of the Caenorhabditis elegans cuticle and are encoded by a large family of 40 to 150 closely related but nonidentical genes. We have determined temporal patterns of mRNA accumulation for a large number of collagen genes by screening recombinant phages and plasmids containing cloned collagen genes under high stringency conditions with 32P-labeled cDNA preparations specific for eggs or three postembryonic molts. We find that collagen mRNA levels are regulated both temporally and quantitatively during C. elegans development. Most genes studied exhibit one of four patterns of mRNA accumulation which correlate with changes in cuticle morphology and collagen protein composition during development. Our results suggest that, in general, there is a progressive activation of new collagen genes during normal development.

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