Role of the Adherens Junction Protein Fascin in the Regulation of Tight Junction Permeability in the Mouse Mammary Gland

2004 ◽  
Author(s):  
Neal E. Beeman ◽  
Margaret Neville
Keyword(s):  
Mammary Gland ◽  
Tight Junction ◽  
Adherens Junction ◽  
Mouse Mammary Gland ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Tight Junction Permeability

scholarly journals A Synthetic Peptide Corresponding to the Extracellular Domain of Occludin Perturbs the Tight Junction Permeability Barrier

1997 ◽  
Vol 136 (2) ◽  
pp. 399-409 ◽  
Author(s):  
Vivian Wong ◽  
Barry M. Gumbiner
Keyword(s):  
Epithelial Cell ◽  
Tight Junction ◽  
Adherens Junction ◽  
Extracellular Domain ◽  
Integral Membrane Protein ◽  
Epithelial Cell Line ◽  
Permeability Barrier ◽  
Junction Protein ◽  
Tight Junction Permeability

Occludin, the putative tight junction integral membrane protein, is an attractive candidate for a protein that forms the actual sealing element of the tight junction. To study the role of occludin in the formation of the tight junction seal, synthetic peptides (OCC1 and OCC2) corresponding to the two putative extracellular domains of occludin were assayed for their ability to alter tight junctions in Xenopus kidney epithelial cell line A6. Transepithelial electrical resistance and paracellular tracer flux measurements indicated that the second extracellular domain peptide (OCC2) reversibly disrupted the transepithelial permeability barrier at concentrations of < 5 μM. Despite the increased paracellular permeability, there were no changes in gross epithelial cell morphology as determined by scanning EM. The OCC2 peptide decreased the amount of occludin present at the tight junction, as assessed by indirect immunofluorescence, as well as decreased total cellular content of occludin, as assessed by Western blot analysis. Pulse-labeling and metabolic chase analysis suggested that this decrease in occludin level could be attributed to an increase in turnover of cellular occludin rather than a decrease in occludin synthesis. The effect on occludin was specific because other tight junction components, ZO-1, ZO-2, cingulin, and the adherens junction protein E-cadherin, were unaltered by OCC2 treatment. Therefore, the peptide corresponding to the second extracellular domain of occludin perturbs the tight junction permeability barrier in a very specific manner. The correlation between a decrease in occludin levels and the perturbation of the tight junction permeability barrier provides evidence for a role of occludin in the formation of the tight junction seal.

116. Contribution of claudin-11 to the inter-Sertoli cell tight junction, in vitro

2005 ◽  
Vol 17 (9) ◽  
pp. 72
Author(s):  
M. J. McCabe ◽  
P. G. Stanton
Keyword(s):  
Tight Junction ◽  
Mrna Expression ◽  
Sertoli Cell ◽  
Adhesion Molecule ◽  
Sertoli Cells ◽  
Adherens Junction ◽  
Adherens Junction Protein ◽  
Junction Protein

The inter-Sertoli cell tight junction (TJ) forms the blood testis barrier (BTB) between Sertoli cells and is composed of three major transmembrane proteins: claudin-11, occludin and junctional adhesion molecule. Formation of the BTB occurs during puberty associating with an increase in circulating gonadotrophins. Claudin-11 and occludin are hormonally regulated in vitro although their importance to the function of the TJ is unknown. The aim of this study was to investigate the contribution of claudin-11 to the inter-Sertoli cell TJ in vitro by blocking gene expression using RNA interference. Two claudin-11-specific siRNA fragments were designed for this purpose. Sertoli cells in primary culture formed stable TJs within 5 days as measured by transepithelial electrical resistance (TER). The addition of siRNA for 2 days resulted in a significant (P < 0.01) 55% (mean, SD, n = 4 cultures) decrease in TER along with a major reduction in claudin-11 localisation to the TJ as assessed by immunocytochemistry. The specificity of the siRNA was shown by the presence of extensive immunostaining of occludin and of the adherens junction protein β-catenin in the same treatments. Similarly, claudin-11 mRNA expression significantly (P < 0.01) decreased by 71% (mean, SD, n = 3 cultures) in response to both claudin-11 siRNA fragments. Occludin mRNA expression was not affected. It is concluded that claudin-11 contributes at least 55% to the function of the rat Sertoli cell TJ in vitro. It is hypothesised that the remaining 45% of TJ function can be attributed to other integral proteins, such as occludin and junctional adhesion molecule. It is expected that claudin-11 and other TJ proteins play a pivotal role in the function of the BTB in vivo with potential implications in fertility and contraception.

scholarly journals The Tight Junction Protein Occludin and the Adherens Junction Protein α-Catenin Share a Common Interaction Mechanism with ZO-1

2004 ◽  
Vol 280 (5) ◽  
pp. 3747-3756 ◽  
Author(s):  
Sebastian L. Müller ◽  
Michael Portwich ◽  
Anke Schmidt ◽  
Darkhan I. Utepbergenov ◽  
Otmar Huber ◽  
...  
Keyword(s):  
Tight Junction ◽  
Interaction Mechanism ◽  
Adherens Junction ◽  
Tight Junction Protein ◽  
Adherens Junction Protein ◽  
Junction Protein

scholarly journals Connecting Exosomes and Connexins

Cancers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 476 ◽  
Author(s):  
Joanna Gemel ◽  
John Kilkus ◽  
Glyn Dawson ◽  
Eric Beyer
Keyword(s):  
Gap Junction ◽  
Extracellular Vesicles ◽  
Recipient Cell ◽  
Adherens Junction ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Endoplasmic Reticulum Protein ◽  
Gap Junction Protein ◽  
Junction Proteins

Intercellular communication is accomplished by passage of ions and small molecules through gap junction channels in directly contacting cells or by secretion and response to transmitters, hormones and extracellular vesicles in cells that are distant from each other. Recent studies have suggested that there may be overlap of these processes; specifically, small extracellular vesicles may contain subunit gap junction proteins, connexins. We isolated and analyzed extracellular vesicles secreted by cultured microvascular endothelial cells. These vesicles had a diameter of ~120 nm. They contained four exosomal proteins (flotillin-1, CD63, CD81 and Alix) and the gap junction protein, connexin43. They did not contain an endoplasmic reticulum protein (Grp94) or an adherens junction protein (VE-cadherin). Secretion of vesicles was increased by treatment of the cells with staurosporine. Our data confirm that the gap junction protein, connexin43, can be secreted in vesicles with the properties of exosomes. Although the role of vesicular connexin is not clearly known, we speculate that it might participate in docking/fusion of the exosomes with the recipient cell, transmission of vesicular contents, or cellular signaling.

scholarly journals Mechanisms involved in AMPK-mediated deposition of tight junction components to the plasma membrane

2020 ◽  
Vol 318 (3) ◽  
pp. C486-C501
Author(s):  
Jingshing Wu ◽  
Pascal Rowart ◽  
Francois Jouret ◽  
Brandon M. Gassaway ◽  
Vanathy Rajendran ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Tight Junction ◽  
Adherens Junction ◽  
Bound State ◽  
Ampk Activation ◽  
Zonula Occludens ◽  
Adherens Junction Protein ◽  
Junction Protein ◽  
Associated Proteins ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase (AMPK) activation promotes early stages of epithelial junction assembly. AMPK activation in MDCK renal epithelial cells facilitates localization of the junction-associated proteins aPKCζ and Par3 to the plasma membrane and promotes conversion of Cdc42, a key regulator of epithelial polarization and junction assembly, to its active GTP bound state. Furthermore, Par3 is an important regulator of AMPK-mediated aPKCζ localization. Both aPKCζ and Par3 serve as intermediates in AMPK-mediated junction assembly, with inhibition of aPKCζ activity or Par3 knockdown disrupting AMPK’s ability to facilitate zonula occludens (ZO-1) localization. AMPK phosphorylates the adherens junction protein afadin and regulates its interaction with the tight-junction protein zonula occludens-1. Afadin is phosphorylated at two critical sites, S228 (residing within an aPKCζ consensus site) and S1102 (residing within an AMPK consensus site), that are differentially regulated during junction assembly and that exert different effects on the process. Expression of phospho-defective mutants (S228A and S1102A) perturbed ZO-1 localization to the plasma membrane during AMPK-induced junction assembly. Expression of S228A increased the ZO-1/afadin interaction, while S1102A reduced this interaction during extracellular calcium-induced junction assembly. Inhibition of aPKCζ activity also increased the ZO-1/afadin interaction. Taken together, these data suggest that aPKCζ phosphorylation of afadin terminates the ZO-1/afadin interaction and thus permits the later stages of junction assembly.

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