Effect of temperature on the assembly of tight junctions and on the mobility of lipids in membranes of HT29 cells

1990 ◽  
Vol 97 (1) ◽  
pp. 119-125
Author(s):  
E. Cohen ◽  
I. Ophir ◽  
Y.I. Henis ◽  
A. Bacher ◽  
Y. Ben Shaul

In the human colon adenocarcinoma cell line HT29, tight junctions can be induced by treatment with appropriate proteases or salt solutions. The temperature dependence of induced tight junction formation is characterized by a marked sigmoidal behavior. The different methods of induction used in this study were characterized by threshold temperatures ranging from 15 to 32 degrees C. Fluorescence photobleaching recovery measurements of the lateral diffusion of a fluorescent phospholipid probe in the cellular plasma membrane gave no evidence for a phase transition or for alteration in the organization of membrane lipids in lateral domains in the temperature range between 0 and 37 degrees C. Moreover, dynamic parameters of the probe in the plasma membrane did not change substantially on mild treatment with trypsin. Thus, the temperature dependence of tight junction formation is not dictated by the bulk properties of the cytoplasmic membrane lipids. The observed temperature dependence suggests that the assembly of tight junctions is a cooperative process, which may involve conformational rearrangement in a protein precursor subsequent to its proteolytic activation.

1997 ◽  
Vol 137 (6) ◽  
pp. 1393-1401 ◽  
Author(s):  
Akira Sakakibara ◽  
Mikio Furuse ◽  
Mitinori Saitou ◽  
Yuhko Ando-Akatsuka ◽  
Shoichiro Tsukita

Occludin is an integral membrane protein localizing at tight junctions in epithelial and endothelial cells. Occludin from confluent culture MDCK I cells resolved as several (>10) bands between 62 and 82 kD in SDS-PAGE, of which two or three bands of the lowest Mr were predominant. Among these bands, the lower predominant bands were essentially extracted with 1% NP-40, whereas the other higher Mr bands were selectively recovered in the NP-40–insoluble fraction. Alkaline phosphatase treatment converged these bands of occludin both in NP-40–soluble and -insoluble fractions into the lowest Mr band, and phosphoamino acid analyses identified phosphoserine (and phosphothreonine weakly) in the higher Mr bands of occludin. These findings indicated that phosphorylation causes an upward shift of occludin bands and that highly phosphorylated occludin resists NP-40 extraction. When cells were grown in low Ca medium, almost all occludin was NP-40 soluble. Switching from low to normal Ca medium increased the amount of NP-40–insoluble occludin within 10 min, followed by gradual upward shift of bands. This insolubilization and the band shift correlated temporally with tight junction formation detected by immunofluorescence microscopy. Furthermore, we found that the anti–chicken occludin mAb, Oc-3, did not recognize the predominant lower Mr bands of occludin (non- or less phosphorylated form) but was specific to the higher Mr bands (phosphorylated form) on immunoblotting. Immunofluorescence microscopy revealed that this mAb mainly stained the tight junction proper of intestinal epithelial cells, whereas other anti-occludin mAbs, which can recognize the predominant lower Mr bands, labeled their basolateral membranes (and the cytoplasm) as well as tight junctions. Therefore, we conclude that non- or less phosphorylated occludin is distributed on the basolateral membranes and that highly phosphorylated occludin is selectively concentrated at tight juctions as the NP-40–insoluble form. These findings suggest that the phosphorylation of occludin is a key step in tight junction assembly.


2007 ◽  
Vol 18 (5) ◽  
pp. 1744-1755 ◽  
Author(s):  
Volker M. Stucke ◽  
Evy Timmerman ◽  
Joel Vandekerckhove ◽  
Kris Gevaert ◽  
Alan Hall

Three groups of evolutionarily conserved proteins have been implicated in the establishment of epithelial cell polarity: the apically-localized proteins of the Par (Par3-Par6-aPKC-Cdc42) and Crumbs groups (Crb3-PALS1-PATJ) and the basolaterally localized proteins of the Dlg group (Dlg1-Scribble-Lgl). During epithelial morphogenesis, these proteins participate in a complex network of interdependent interactions that define the position and functional organization of adherens junctions and tight junctions. However, the biochemical pathways through which they control polarity are poorly understood. In this study, we identify an interaction between endogenous hDlg1 and MPP7, a previously uncharacterized MAGUK-p55 subfamily member. We find that MPP7 targets to the lateral surface of epithelial cells via its L27N domain, through an interaction with hDlg1. Loss of either hDlg1 or MPP7 from epithelial Caco-2 cells results in a significant defect in the assembly and maintenance of functional tight junctions. We conclude that the formation of a complex between hDlg1 and MPP7 promotes epithelial cell polarity and tight junction formation.


2009 ◽  
Vol 296 (1) ◽  
pp. L101-L108 ◽  
Author(s):  
Yael Grumbach ◽  
Nga Vu Thi Quynh ◽  
Raphaël Chiron ◽  
Valérie Urbach

Lipoxin A4 (LXA4) is a biologically active eicosanoid produced in human airways that displays anti-inflammatory properties. In cystic fibrosis and severe asthma, LXA4 production has been reported to be decreased, and, in such diseases, one of the consequences of airway inflammation is disruption of the tight junctions. In the present study, we investigated the possible role of LXA4 on tight junction formation, using transepithelial electrical resistance (TER) measurements, Western blotting, and immunofluorescence. We observed that exposure to LXA4 (100 nM) for 2 days significantly increased zonula occludens-1 (ZO-1), claudin-1, and occludin expression at the plasma membrane of confluent human bronchial epithelial 16HBE14o- cells. LXA4 (100 nM) stimulated the daily increase of the 16HBE14o- cell monolayer TER, and this effect was inhibited by boc-2 (LXA4 receptor antagonist). LXA4 also had a rapid effect on ZO-1 immunofluorescence at the plasma membrane and increased TER within 10 min. In conclusion, our experiments provide evidence that LXA4 plays certainly a new role for the regulation of tight junction formation and stimulation of the localization and expression of ZO-1 at the plasma membrane through a mechanism involving the LXA4 receptor.


2002 ◽  
Vol 115 (12) ◽  
pp. 2485-2495 ◽  
Author(s):  
Tomonori Hirose ◽  
Yasushi Izumi ◽  
Yoji Nagashima ◽  
Yoko Tamai-Nagai ◽  
Hidetake Kurihara ◽  
...  

The mammalian protein ASIP/PAR-3 interacts with atypical protein kinase C isotypes (aPKC) and shows overall sequence similarity to the invertebrate proteins C. elegans PAR-3 and Drosophila Bazooka, which are crucial for the establishment of polarity in various cells. The physical interaction between ASIP/PAR-3 and aPKC is also conserved in C. elegans PAR-3 and PKC-3 and in Drosophila Bazooka and DaPKC. In mammals, ASIP/PAR-3 colocalizes with aPKC and concentrates at the tight junctions of epithelial cells, but the biological meaning of ASIP/PAR-3 in tight junctions remains to be clarified. In the present study, we show that ASIP/PAR-3 staining distributes to the subapical domain of epithelial cell-cell junctions, including epithelial cells with less-developed tight junctions, in clear contrast with ZO-1, another tight-junction-associated protein, the staining of which is stronger in cells with well-developed tight junctions. Consistently, immunogold electron microscopy revealed that ASIP/PAR-3 concentrates at the apical edge of tight junctions, whereas ZO-1 distributes alongside tight junctions. To clarify the meaning of this characteristic localization of ASIP, we analyzed the effects of overexpressed ASIP/PAR-3 on tight junction formation in cultured epithelial MDCK cells. The induced overexpression of ASIP/PAR-3, but not its deletion mutant lacking the aPKC-binding sequence, promotes cell-cell contact-induced tight junction formation in MDCK cells when evaluated on the basis of transepithelial electrical resistance and occludin insolubilization. The significance of the aPKC-binding sequence in tight junction formation is also supported by the finding that the conserved PKC-phosphorylation site within this sequence,ASIP-Ser827, is phosphorylated at the most apical tip of cell-cell contacts during the initial phase of tight junction formation in MDCK cells. Together,our present data suggest that ASIP/PAR-3 regulates epithelial tight junction formation positively through interaction with aPKC.


1993 ◽  
Vol 121 (3) ◽  
pp. 491-502 ◽  
Author(s):  
M Itoh ◽  
A Nagafuchi ◽  
S Yonemura ◽  
T Kitani-Yasuda ◽  
S Tsukita ◽  
...  

We previously identified a 220-kD constitutive protein of the plasma membrane undercoat which colocalizes at the immunofluorescence microscopic level with cadherins and occurs not only in epithelial M., S. Yonemura, A. Nagafuchi, Sa. Tsukita, and Sh. Tsukita. 1991. J. Cell Biol. 115:1449-1462). To clarify the nature and possible functions of this protein, we cloned its full-length cDNA and sequenced it. Unexpectedly, we found mouse 220-kD protein to be highly homologous to rat protein ZO-1, only a part of which had been already sequenced. This relationship was confirmed by immunoblotting with anti-ZO-1 antibody. As protein ZO-1 was originally identified as a component exclusively underlying tight junctions in epithelial cells, where cadherins are not believed to be localized, we analyzed the distribution of cadherins and the 220-kD protein by ultrathin cryosection immunoelectron microscopy. We found that in non-epithelial cells lacking tight junctions cadherins and the 220-kD protein colocalize, whereas in epithelial cells (e.g., intestinal epithelial cells) bearing well-developed tight junctions cadherins and the 220-kD protein are clearly segregated into adherens and tight junctions, respectively. Interestingly, in epithelial cells such as hepatocytes, which tight junctions are not so well developed, the 220-kD protein is detected not only in the tight junction zone but also at adherens junctions. Furthermore, we show in mouse L cells transfected with cDNAs encoding N-, P-, E-cadherins that cadherins interact directly or indirectly with the 220-kD protein. Possible functions of the 220-kD protein (ZO-1) are discussed with special reference to the molecular mechanism for adherens and tight junction formation.


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