scholarly journals PATJ regulates tight junction formation and polarity in mammalian epithelial cells

2005 ◽  
Vol 168 (5) ◽  
pp. 705-711 ◽  
Author(s):  
Kunyoo Shin ◽  
Sam Straight ◽  
Ben Margolis
Keyword(s):  
Tight Junction ◽  
Protein Complexes ◽  
Transmembrane Protein ◽  
Complex Function ◽  
Cell Polarization ◽  
Tight Junction Protein ◽  
Apical Region ◽  
Tight Junction Formation ◽  
Junction Protein ◽  
Junction Formation

Recent studies have revealed an important role for tight junction protein complexes in epithelial cell polarity. One of these complexes contains the apical transmembrane protein, Crumbs, and two PSD95/discs large/zonula occludens domain proteins, protein associated with Lin seven 1 (PALS1)/Stardust and PALS1-associated tight junction protein (PATJ). Although Crumbs and PALS1/Stardust are known to be important for cell polarization, recent studies have suggested that Drosophila PATJ is not essential and its function is unclear. Here, we find that PATJ is targeted to the apical region and tight junctions once cell polarization is initiated. We show using RNAi techniques that reduction in PATJ expression leads to delayed tight junction formation as well as defects in cell polarization. These effects are reversed by reintroduction of PATJ into these RNAi cells. This study provides new functional information on PATJ as a polarity protein and increases our understanding of the Crumbs–PALS1–PATJ complex function in epithelial polarity.

Tight junction protein cingulin is expressed by maternal and embryonic genomes during early mouse development

Development ◽  
1993 ◽  
Vol 117 (3) ◽  
pp. 1145-1151 ◽  
Author(s):  
Q. Javed ◽  
T.P. Fleming ◽  
M. Hay ◽  
S. Citi
Keyword(s):  
Tight Junction ◽  
Cell Mass ◽  
Preimplantation Embryos ◽  
Cell Contact ◽  
Mouse Development ◽  
Early Cleavage ◽  
Cell Stage ◽  
Tight Junction Formation ◽  
Junction Protein ◽  
Junction Formation

The expression of the tight junction peripheral membrane protein, cingulin (140 × 10(3) M(r), was investigated in mouse eggs and staged preimplantation embryos by immunoblotting and immunoprecipitation. Polyclonal antibody to chicken brush cingulin detected a single 140 × 10(3) M(r) protein in immunoblots of unfertilised eggs and all preimplantation stages. Relative protein levels were high in eggs and early cleavage stages, declined during later cleavage and increased again in expanding blastocysts. Quantitative immunoprecipitation of metabolically labelled eggs and staged embryos also revealed a biphasic pattern for cingulin synthesis with relative net levels being high in unfertilised eggs, minimal during early cleavage, rising 2.3-fold specifically at the onset of compaction (8-cell stage, when tight junction formation begins), and increasing further at a linear rate during morula and blastocyst stages. Cingulin synthesis in eggs is not influenced by fertilisation (or aging, if unfertilised), but this level declines sharply after first cleavage. These results indicate that cingulin is expressed by both maternal and embryonic genomes. The turnover of maternal cingulin (unfertilised eggs) and embryonic cingulin at a stage before tight junction formation begins (4-cell stage) is higher (t1/2 approximately 4 hours) than cingulin synthesised after tight junction formation (blastocysts; t1/2 approximately 10 hours). This increase in cingulin stability is reversed in the absence of extracellular calcium. Cingulin synthesis is also tissue-specific in blastocysts, being up-regulated in trophectoderm and down-regulated in the inner cell mass. Taken together, the results suggest that (i) cingulin may have a role during oogenesis and (ii) cell-cell contact patterns regulate cingulin biosynthesis during early morphogenesis, contributing to lineage-specific epithelial maturation.

scholarly journals PALS1 Regulates E-Cadherin Trafficking in Mammalian Epithelial Cells

2007 ◽  
Vol 18 (3) ◽  
pp. 874-885 ◽  
Author(s):  
Qian Wang ◽  
Xiao-Wei Chen ◽  
Ben Margolis
Keyword(s):  
Tight Junction ◽  
Adherens Junction ◽  
Cell Periphery ◽  
Madin Darby Canine Kidney ◽  
Tight Junction Formation ◽  
Junction Protein ◽  
Evolutionarily Conserved ◽  
Junction Formation ◽  
Darby Canine Kidney ◽  
E Cadherin

Protein Associated with Lin Seven 1 (PALS1) is an evolutionarily conserved scaffold protein that targets to the tight junction in mammalian epithelia. Prior work in our laboratory demonstrated that the knockdown of PALS1 in Madin Darby canine kidney cells leads to tight junction and polarity defects. We have created new PALS1 stable knockdown cell lines with more profound reduction of PALS1 expression, and a more severe defect in tight junction formation was observed. Unexpectedly, we also observed a severe adherens junction defect, and both defects were corrected when PALS1 wild type and certain PALS1 mutants were expressed in the knockdown cells. We found that the adherens junction structural component E-cadherin was not effectively delivered to the cell surface in the PALS1 knockdown cells, and E-cadherin puncta accumulated in the cell periphery. The exocyst complex was also found to be mislocalized in PALS1 knockdown cells, potentially explaining why E-cadherin trafficking is disrupted. Our results suggest a broad and evolutionarily conserved role for the tight junction protein PALS1 in the biogenesis of adherens junction.

scholarly journals Spatio-temporal expression pattern and role of the tight junction protein MarvelD3 in pancreas development and function

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charlotte Heymans ◽  
Ophélie Delcorte ◽  
Catherine Spourquet ◽  
Mylah Villacorte-Tabelin ◽  
Sébastien Dupasquier ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tight Junction ◽  
Expression Pattern ◽  
Pancreatic Tissue ◽  
Cell Polarization ◽  
Tight Junction Protein ◽  
Jnk Pathway ◽  
Genetic Ablation ◽  
Junction Protein

AbstractTight junction complexes are involved in the establishment and maintenance of cell polarity and the regulation of signalling pathways, controlling biological processes such as cell differentiation and cell proliferation. MarvelD3 is a tight junction protein expressed in adult epithelial and endothelial cells. In Xenopus laevis, MarvelD3 morphants present differentiation defects of several ectodermal derivatives. In vitro experiments further revealed that MarvelD3 couples tight junctions to the MEKK1-JNK pathway to regulate cell behaviour and survival. In this work, we found that MarvelD3 is expressed from early developmental stages in the exocrine and endocrine compartments of the pancreas, as well as in endothelial cells of this organ. We thoroughly characterized MarvelD3 expression pattern in developing pancreas and evaluated its function by genetic ablation. Surprisingly, inactivation of MarvelD3 in mice did not alter development and differentiation of the pancreatic tissue. Moreover, tight junction formation and organization, cell polarization, and activity of the JNK-pathway were not impacted by the deletion of MarvelD3.

scholarly journals The Tight Junction Protein ZO-1 Establishes a Link between the Transmembrane Protein Occludin and the Actin Cytoskeleton

1998 ◽  
Vol 273 (45) ◽  
pp. 29745-29753 ◽  
Author(s):  
Alan S. Fanning ◽  
Brian J. Jameson ◽  
Lynne A. Jesaitis ◽  
James Melvin Anderson
Keyword(s):  
Tight Junction ◽  
Actin Cytoskeleton ◽  
Transmembrane Protein ◽  
Tight Junction Protein ◽  
Junction Protein
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