Behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions

Tricellulin is an important component of tricellular tight junctions (TJs) and is involved in the formation of tricellular contacts. However, little is known about its regulation during the assembly and disassembly of tricellular TJs. By using the well-differentiated pancreatic cancer cell line HPAC...

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Main Authors:	Takasawa, Akira, Kojima, Takashi, Ninomiya, Takafumi, Tsujiwaki, Mitsuhiro, Murata, Masaki, Tanaka, Satoshi, Sawada, Norimasa
Format:	Online
Language:	English
Published:	Springer-Verlag 2012
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3536962/

id	pubmed-3536962
recordtype	oai_dc
spelling	pubmed-35369622013-01-04 Behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions Takasawa, Akira Kojima, Takashi Ninomiya, Takafumi Tsujiwaki, Mitsuhiro Murata, Masaki Tanaka, Satoshi Sawada, Norimasa Regular Article Tricellulin is an important component of tricellular tight junctions (TJs) and is involved in the formation of tricellular contacts. However, little is known about its regulation during the assembly and disassembly of tricellular TJs. By using the well-differentiated pancreatic cancer cell line HPAC, which highly expresses tricellulin at tricellular contacts, we have investigated changes in the localization, expression and phosphorylation of tricellulin and in its TJ functions as a barrier and fence during the destruction and formation of TJs induced by changes in the extracellular calcium concentration. During both extracellular Ca2+ depletion caused by EGTA treatment and Ca2+ repletion after Ca2+ starvation, the expression of tricellulin increased in whole lysates and in Triton-X-100-insoluble fractions without any change in its mRNA. The increases in immunoreactivity revealed by Western blotting were prevented by alkaline phosphatase treatment. Immunoprecipitation assays showed that tricellulin was phosphorylated on threonine residues when it increased after Ca2+ depletion and repletion. In the early stage after Ca2+ repletion, tricellulin was expressed not only at tricellular contacts but also in the cytoplasm and at bicellular borders. In confocal laser microscopy, tricellulin was observed at the apical-most regions and basolateral membranes of tricellular contacts after Ca2+ repletion. Knockdown of tricellulin delayed the recovery of the barrier and fence functions after Ca2+ repletion. Thus, the dynamic behavior of tricellulin during the destruction and formation of TJs under various extracellular calcium conditions seems to be closely associated with the barrier and fence functions of TJs. Springer-Verlag 2012-10-17 2013-01 /pmc/articles/PMC3536962/ /pubmed/23073616 http://dx.doi.org/10.1007/s00441-012-1512-7 Text en © The Author(s) 2012
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Takasawa, Akira Kojima, Takashi Ninomiya, Takafumi Tsujiwaki, Mitsuhiro Murata, Masaki Tanaka, Satoshi Sawada, Norimasa
spellingShingle	Takasawa, Akira Kojima, Takashi Ninomiya, Takafumi Tsujiwaki, Mitsuhiro Murata, Masaki Tanaka, Satoshi Sawada, Norimasa Behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions
author_facet	Takasawa, Akira Kojima, Takashi Ninomiya, Takafumi Tsujiwaki, Mitsuhiro Murata, Masaki Tanaka, Satoshi Sawada, Norimasa
author_sort	Takasawa, Akira
title	Behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions
title_short	Behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions
title_full	Behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions
title_fullStr	Behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions
title_full_unstemmed	Behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions
title_sort	behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions
description	Tricellulin is an important component of tricellular tight junctions (TJs) and is involved in the formation of tricellular contacts. However, little is known about its regulation during the assembly and disassembly of tricellular TJs. By using the well-differentiated pancreatic cancer cell line HPAC, which highly expresses tricellulin at tricellular contacts, we have investigated changes in the localization, expression and phosphorylation of tricellulin and in its TJ functions as a barrier and fence during the destruction and formation of TJs induced by changes in the extracellular calcium concentration. During both extracellular Ca2+ depletion caused by EGTA treatment and Ca2+ repletion after Ca2+ starvation, the expression of tricellulin increased in whole lysates and in Triton-X-100-insoluble fractions without any change in its mRNA. The increases in immunoreactivity revealed by Western blotting were prevented by alkaline phosphatase treatment. Immunoprecipitation assays showed that tricellulin was phosphorylated on threonine residues when it increased after Ca2+ depletion and repletion. In the early stage after Ca2+ repletion, tricellulin was expressed not only at tricellular contacts but also in the cytoplasm and at bicellular borders. In confocal laser microscopy, tricellulin was observed at the apical-most regions and basolateral membranes of tricellular contacts after Ca2+ repletion. Knockdown of tricellulin delayed the recovery of the barrier and fence functions after Ca2+ repletion. Thus, the dynamic behavior of tricellulin during the destruction and formation of TJs under various extracellular calcium conditions seems to be closely associated with the barrier and fence functions of TJs.
publisher	Springer-Verlag
publishDate	2012
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3536962/
_version_	1611944594037014528

Behavior of tricellulin during destruction and formation of tight junctions under various extracellular calcium conditions

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