scholarly journals Identification of ZO-1: a high molecular weight polypeptide associated with the tight junction (zonula occludens) in a variety of epithelia.

1986 ◽  
Vol 103 (3) ◽  
pp. 755-766 ◽  
Author(s):  
B R Stevenson ◽  
J D Siliciano ◽  
M S Mooseker ◽  
D A Goodenough

A tight junction-enriched membrane fraction has been used as immunogen to generate a monoclonal antiserum specific for this intercellular junction. Hybridomas were screened for their ability to both react on an immunoblot and localize to the junctional complex region on frozen sections of unfixed mouse liver. A stable hybridoma line has been isolated that secretes an antibody (R26.4C) that localizes in thin section images of isolated mouse liver plasma membranes to the points of membrane contact at the tight junction. This antibody recognizes a polypeptide of approximately 225,000 D, detectable in whole liver homogenates as well as in the tight junction-enriched membrane fraction. R26.4C localizes to the junctional complex region of a number of other epithelia, including colon, kidney, and testis, and to arterial endothelium, as assayed by immunofluorescent staining of cryostat sections of whole tissue. This antibody also stains the junctional complex region in confluent monolayers of the Madin-Darby canine kidney epithelial cell line. Immunoblot analysis of Madin-Darby canine kidney cells demonstrates the presence of a polypeptide similar in molecular weight to that detected in liver, suggesting that this protein is potentially a ubiquitous component of all mammalian tight junctions. The 225-kD tight junction-associated polypeptide is termed "ZO-1."

1988 ◽  
Vol 106 (4) ◽  
pp. 1141-1149 ◽  
Author(s):  
J M Anderson ◽  
B R Stevenson ◽  
L A Jesaitis ◽  
D A Goodenough ◽  
M S Mooseker

ZO-1, originally identified by mAb techniques, is the first protein shown to be specifically associated with the tight junction. Here we describe and compare the physical characteristics of ZO-1 from mouse liver and the Madin-Darby canine kidney (MDCK) epithelial cell line. The ZO-1 polypeptide has an apparent size of 225 kD in mouse tissues and 210 kD in canine-derived MDCK cells as determined by SDS-PAGE/immunoblot analysis. ZO-1 from both sources is optimally solubilized from isolated plasma membranes by either 6 M urea or high pH conditions; partial solubilization occurs with 0.3 M KCl. The nonionic detergents, Triton X-100 and octyl-beta-D-glucopyranoside, do not solubilize ZO-1. These solubility properties indicate that ZO-1 is a peripherally associated membrane protein. ZO-1 was purified to electrophoretic homogeneity from [35S]methionine metabolically labeled MDCK cells by a combination of gel filtration and immunoaffinity chromatography. Purified ZO-1 has an s20,w of 5.3 and Stokes radius of 8.6 nm. These values suggest that purified ZO-1 is an asymmetric monomeric molecule. Corresponding values for mouse liver ZO-1, characterized in impure protein extracts, were 6 s20,w and 9 nm. ZO-1 was shown to be a phosphoprotein in MDCK cells metabolically labeled with [32P]orthophosphate; analysis of phosphoamino acids from purified ZO-1 revealed only phosphoserine. ZO-1 epitope number was determined by Scatchard analysis of competitive and saturable binding of two different 125I-mAbs to SDS-solubilized proteins from liver and MDCK cells immobilized on nitrocellulose. Saturation binding occurs at 26 ng mAb/mg liver and 63 ng/mg of MDCK cell protein. This is equivalent to 30,000 ZO-1 molecules per MDCK cell assuming a single epitope/ZO-1 molecule.


2003 ◽  
Vol 14 (5) ◽  
pp. 1757-1768 ◽  
Author(s):  
Erika S. Wittchen ◽  
Julie Haskins ◽  
Bruce R. Stevenson

We previously demonstrated that exogenous expression of a truncated form of the tight junction protein ZO-3 affected junctional complex assembly and function. Current results indicate that this ZO-3 construct influences actin cytoskeleton dynamics more globally. We show that expression of the amino-terminal half of ZO-3 (NZO-3) in Madin-Darby canine kidney cells results in a decreased number of stress fibers and focal adhesions and causes an increased rate of cell migration in a wound healing assay. We also demonstrate that RhoA activity is reduced in NZO-3–expressing cells. We determined that ZO-3 interacts with p120 catenin and AF-6, proteins localized to the junctional complex and implicated in signaling pathways important for cytoskeleton regulation and cell motility. We also provide evidence that NZO-3 interacts directly with the C terminus of ZO-3, and we propose a model where altered interactions between ZO-3 and p120 catenin in NZO-3–expressing cells affect RhoA GTPase activity. This study reveals a potential link between ZO-3 and RhoA-related signaling events.


1987 ◽  
Vol 7 (4) ◽  
pp. 1326-1337
Author(s):  
S L Warren ◽  
W J Nelson

Madin-Darby canine kidney (MDCK) cells form polarized, multicellular epithelial structures in vitro. Low-level expression of pp60v-src in MDCK cells elicits plasticity in these multicellular structures. Plasticity was revealed by the displacement of cells from mechanically stressed regions of the epithelial monolayers; however, the two-dimensional relationship between the cells in the remainder of the monolayer was maintained. Electron microscopy of multicellular structures revealed abnormal separation of the lateral membranes of adjacent cells and selective uncoupling of the junctional complex; the zonula adherens was disrupted, but the zonula occludens and desmosomes were retained. Significantly, this result was not accompanied by transformation of the cells, as judged by the absence of anchorage-independent growth potential. These results demonstrate a nonmitogenic biological activity of pp60v-src which is experimentally dissociable from transformation. This morphoregulatory action on higher-order epithelial structures may reflect a function of related cellular tyrosine kinases.


1987 ◽  
Vol 7 (4) ◽  
pp. 1326-1337 ◽  
Author(s):  
S L Warren ◽  
W J Nelson

Madin-Darby canine kidney (MDCK) cells form polarized, multicellular epithelial structures in vitro. Low-level expression of pp60v-src in MDCK cells elicits plasticity in these multicellular structures. Plasticity was revealed by the displacement of cells from mechanically stressed regions of the epithelial monolayers; however, the two-dimensional relationship between the cells in the remainder of the monolayer was maintained. Electron microscopy of multicellular structures revealed abnormal separation of the lateral membranes of adjacent cells and selective uncoupling of the junctional complex; the zonula adherens was disrupted, but the zonula occludens and desmosomes were retained. Significantly, this result was not accompanied by transformation of the cells, as judged by the absence of anchorage-independent growth potential. These results demonstrate a nonmitogenic biological activity of pp60v-src which is experimentally dissociable from transformation. This morphoregulatory action on higher-order epithelial structures may reflect a function of related cellular tyrosine kinases.


2001 ◽  
Vol 12 (8) ◽  
pp. 2257-2274 ◽  
Author(s):  
Raul Rojas ◽  
Wily G. Ruiz ◽  
Som-Ming Leung ◽  
Tzuu-Shuh Jou ◽  
Gerard Apodaca

Polarized epithelial cells maintain the asymmetric composition of their apical and basolateral membrane domains by at least two different processes. These include the regulated trafficking of macromolecules from the biosynthetic and endocytic pathway to the appropriate membrane domain and the ability of the tight junction to prevent free mixing of membrane domain-specific proteins and lipids. Cdc42, a Rho family GTPase, is known to govern cellular polarity and membrane traffic in several cell types. We examined whether this protein regulated tight junction function in Madin-Darby canine kidney cells and pathways that direct proteins to the apical and basolateral surface of these cells. We used Madin-Darby canine kidney cells that expressed dominant-active or dominant-negative mutants of Cdc42 under the control of a tetracycline-repressible system. Here we report that expression of dominant-active Cdc42V12 or dominant-negative Cdc42N17 altered tight junction function. Expression of Cdc42V12 slowed endocytic and biosynthetic traffic, and expression of Cdc42N17 slowed apical endocytosis and basolateral to apical transcytosis but stimulated biosynthetic traffic. These results indicate that Cdc42 may modulate multiple cellular pathways required for the maintenance of epithelial cell polarity.


2000 ◽  
Vol 11 (3) ◽  
pp. 849-862 ◽  
Author(s):  
Yan-hua Chen ◽  
Qun Lu ◽  
Eveline E. Schneeberger ◽  
Daniel A. Goodenough

In the Madin-Darby canine kidney epithelial cell line, the proteins occludin and ZO-1 are structural components of the tight junctions that seal the paracellular spaces between the cells and contribute to the epithelial barrier function. In Ras-transformed Madin-Darby canine kidney cells, occludin, claudin-1, and ZO-1 were absent from cell–cell contacts but were present in the cytoplasm, and the adherens junction protein E-cadherin was weakly expressed. After treatment of the Ras-transformed cells with the mitogen-activated protein kinase kinase (MEK1) inhibitor PD98059, which blocks the activation of mitogen-activated protein kinase (MAPK), occludin, claudin-1, and ZO-1 were recruited to the cell membrane, tight junctions were assembled, and E-cadherin protein expression was induced. Although it is generally believed that E-cadherin–mediated cell–cell adhesion is required for tight junction assembly, the recruitment of occludin to the cell–cell contact area and the restoration of epithelial cell morphology preceded the appearance of E-cadherin at cell–cell contacts. Both electron microscopy and a fourfold increase in the transepithelial electrical resistance indicated the formation of functional tight junctions after MEK1 inhibition. Moreover, inhibition of MAPK activity stabilized occludin and ZO-1 by differentially increasing their half-lives. We also found that during the process of tight junction assembly after MEK1 inhibition, tyrosine phosphorylation of occludin and ZO-1, but not claudin-1, increased significantly. Our study demonstrates that down-regulation of the MAPK signaling pathway causes the restoration of epithelial cell morphology and the assembly of tight junctions in Ras-transformed epithelial cells and that tyrosine phosphorylation of occludin and ZO-1 may play a role in some aspects of tight junction formation.


2012 ◽  
Vol 302 (2) ◽  
pp. R300-R311 ◽  
Author(s):  
M. B. Engelund ◽  
A. S. L. Yu ◽  
J. Li ◽  
S. S. Madsen ◽  
N. J. Færgeman ◽  
...  

Claudins are the major determinants of paracellular epithelial permeability in multicellular organisms. In Atlantic salmon ( Salmo salar L.), we previously found that mRNA expression of the abundant gill-specific claudin 30 decreases during seawater (SW) acclimation, suggesting that this claudin is associated with remodeling of the epithelium during salinity change. This study investigated localization, protein expression, and function of claudin 30. Confocal microscopy showed that claudin 30 protein was located at cell-cell interfaces in the gill filament in SW- and fresh water (FW)-acclimated salmon, with the same distribution, overall, as the tight junction protein ZO-1. Claudin 30 was located at the apical tight junction interface and in cell membranes deeper in the epithelia. Colocalization with the α-subunit of the Na+-K+-ATPase was negligible, suggesting limited association with mitochondria-rich cells. Immunoblotting of gill samples showed lower claudin 30 protein expression in SW than FW fish. Retroviral transduction of claudin 30 into Madin-Darby canine kidney cells resulted in a decreased conductance of 19%. The decreased conductance correlated with a decreased permeability of the cell monolayer to monovalent cations, whereas permeability to chloride was unaffected. Confocal microscopy revealed that claudin 30 was expressed in the lateral membrane, as well as in tight junctions of Madin-Darby canine kidney cells, thereby paralleling the findings in the native gill. This study suggests that claudin 30 functions as a cation barrier between pavement cells in the gill and also has a general role in cell-cell adhesion in deeper layers of the epithelium.


2016 ◽  
Vol 105 (2) ◽  
pp. 630-638 ◽  
Author(s):  
Mathias Kaiser ◽  
Sudharani Chalapala ◽  
Christian Gorzelanny ◽  
Ramu Sridhar Perali ◽  
Francisco Martin Goycoolea

2007 ◽  
Vol 292 (3) ◽  
pp. C1094-C1102 ◽  
Author(s):  
Shobha Gopalakrishnan ◽  
Mark A. Hallett ◽  
Simon J. Atkinson ◽  
James A. Marrs

Renal ischemia and in vitro ATP depletion result in disruption of the epithelial tight junction barrier, which is accompanied by breakdown of plasma membrane polarity. Tight junction formation is regulated by evolutionarily conserved complexes, including that of atypical protein kinase C (aPKC), Par3, and Par6. The aPKC signaling complex is activated by Rac and regulated by protein phosphorylation and associations with other tight junction regulatory proteins, for example, mLgl. In this study, we examined the role of aPKC signaling complex during ATP depletion and recovery in Madin-Darby canine kidney cells. ATP depletion reduced Rac GTPase activity and induced Par3, aPKCζ, and mLgl-1 redistribution from sites of cell-cell contact, which was restored following recovery from ATP depletion. Zonula occludens (ZO)-1 and Par3 phosphorylation was reduced and association of aPKCζ with its substrates Par3 and mLgl-1 was stabilized in ATP-depleted Madin-Darby canine kidney cells. ATP depletion also induced a stable association of Par3 with Tiam-1, a Rac GTPase exchange factor, which explains how aPKCζ and Rac activities were suppressed. Experimental inhibition of aPKCζ during recovery from ATP depletion interfered with reassembly of ZO-1 and Par3 at cell junctions. These data indicate that aPKC signaling is impaired during ATP depletion, participates in tight junction disassembly during cell injury and is important for tight junction reassembly during recovery.


Sign in / Sign up

Export Citation Format

Share Document