Induction of Tight Junctions in Human Connexin 32 (hCx32)-Transfected Mouse Hepatocytes: Connexin 32 Interacts with Occludin

Kojima, Takashi; Sawada, Norimasa; Chiba, Hideki; Kokai, Yasuo; Yamamoto, Masao; Urban, Marcia; Lee, Gang Hong; Hertzberg, Elliot L.; Mochizuki, Yohichi; Spray, David C.

doi:10.1006/bbrc.1999.1778

Cited by 87 publications

(53 citation statements)

References 38 publications

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“…The possibility of an occludin-connexin 26 interaction provides an interesting explanation for several previously reported observations that suggest a proximity of TJ and gap junction structures (3,5). A recent study has shown connexin 32 to directly interact with occludin (52). Our data localized the specific interaction of connexin 26 to a 27-amino acid domain of occludin.…”

Section: Zo-1 Interacts With Both Coiled-coil Domain Baitsupporting

confidence: 69%

The Coiled-coil Domain of Occludin Can Act to Organize Structural and Functional Elements of the Epithelial Tight Junction

Nusrat

Chen

Foley

et al. 2000

Journal of Biological Chemistry

179

124

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Occludin is an integral membrane protein that has been suggested to play a role in the organization and dynamic function of the epithelial tight junction (TJ). A number of other proteins have also been described to localize to the TJ. We have used a novel bait peptide method to investigate potential protein-protein interactions of the putative coiled-coil domain of occludin with some of these other TJ proteins. A 27-amino acid peptide of the human occludin sequence was synthesized, biotinylated at the N terminus, and modified to contain a photoactive moiety at either its hydrophobic or hydrophilic surface. These bait peptides were ␣-helical in solution, characteristic of coiled-coil structures. Photoactivation studies in the presence and absence of control peptides were used to assess the potential interactions in polarized sheets of a human intestinal cell line T84. Although a large number of proteins associated with the TJ or that are known to be involved in regulatory events of epithelial cells failed to be specifically labeled, occludin itself, ZO-1, protein kinase C-, c-Yes, the regulatory subunit of phosphatidylinositol 3-kinase, and the gap junction component connexin 26 were specifically labeled. Our data demonstrate the potential of one specific domain of occludin, contained within 27 amino acids, to coordinate the binding of proteins that have been previously suggested to modulate TJ structure and function.Over the last decade a number of proteins have been identified that localize to the tight junction (TJ) 1 structures of epithelial cells. Possible functional interactions between these proteins have been described (reviewed in Ref. 1). Critical extracellular interactions in TJs have been attributed to two transmembrane proteins, claudin(s) and occludin (2). Although it has been suggested that claudins recruit occludin to TJ sites (3), several recent studies have suggested instead that occludin dynamically regulates claudin-based TJ strands. Transfection of occludin mutants lacking either the intracellular (4) or extracellular (5) domains induces disruption of epithelial barrier properties. In addition, TJ barrier function is also influenced by incubation with peptides containing the two extracellular loop amino acid sequences (6 -8). As yet, analogous studies have not been described for claudin(s). Finally, disruption of TJ function mediated by the constitutive activation of Raf-1 is associated with down-regulation of occludin and claudin-1 expression, an effect that can be reversed by the reintroduction of occludin expression that in turn restores claudin-1 protein levels (9).Human occludin is approximately 65 kDa with what appears to be a 65-amino acid cytosolic N terminus, two extracellular loops of 46 and 48 amino acids separated by a 10-amino acid cytosolic loop, and a C-terminal tail of approximately 255 amino acids (10). Both the N-and C-terminal domains have a large number of serine and threonine residues, and the functionally active form of the protein localizing to the TJ appears to be hype...

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Section: Zo-1 Interacts With Both Coiled-coil Domain Baitsupporting

confidence: 69%

The Coiled-coil Domain of Occludin Can Act to Organize Structural and Functional Elements of the Epithelial Tight Junction

Nusrat

Chen

Foley

et al. 2000

Journal of Biological Chemistry

179

124

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“…Furthermore, TEM showed microvilli on the luminal surfaces of bile ductlike structures and junctional complexes, the basis of the cytoskeleton of epithelial tissue. Finally, strong expression of Cx32, which is the main protein of hepatocyte gap junctions, was observed [40,41] . These findings were considered to be the features of organoids which had adhered to the beads firmly until reaching a certain size.…”

Section: Discussionmentioning

confidence: 98%

Hepatic reconstruction from fetal porcine liver cells using a radial flow bioreactor

Ishii¹,

Saito²,

Marushima³

et al. 2008

WJG

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“…Previous work from our group described the gradual loss of β-catenin expression in older Mist1 KO animals (Pin et al, 2001) and it has been suggested that the loss of one type of junctional complex (e.g. adherens) can lead to the loss of other complexes (Fujimoto et al, 1997;Kojima et al, 1999). In order to determine if the loss of Cx32 expression was a result of disruption in other cell junctions, Mist1 KO and WT pancreas samples were co-stained for Cx32 and markers for zymogen granules (amylase), adherens junctions (β-catenin) and tight junctions (occludin).…”

Section: Expression Of Cx32 Is Significantly Reduced In Mist1 Ko Pancmentioning

confidence: 96%

Exocrine specific expression of Connexin32 is dependent on the basic helix-loop-helix transcription factor Mist1

Rukstalis

Kowalik

Zhu

et al. 2003

Journal of Cell Science

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Induction of Tight Junctions in Human Connexin 32 (hCx32)-Transfected Mouse Hepatocytes: Connexin 32 Interacts with Occludin

Cited by 87 publications

References 38 publications

The Coiled-coil Domain of Occludin Can Act to Organize Structural and Functional Elements of the Epithelial Tight Junction

The Coiled-coil Domain of Occludin Can Act to Organize Structural and Functional Elements of the Epithelial Tight Junction

Hepatic reconstruction from fetal porcine liver cells using a radial flow bioreactor

Exocrine specific expression of Connexin32 is dependent on the basic helix-loop-helix transcription factor Mist1

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