Apoptotic Fragmentation of Tricellulin
Apoptotic extrusion of cells from epithelial cell layers is of central importance for epithelial homeostasis. As a prerequisite cell−cell contacts between apoptotic cells and their neighbors have to be dissociated. Tricellular tight junctions (tTJs) represent specialized structures that se...
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doaj-ce4d4b6b91d74840b454020689c3ee742020-11-25T01:15:08ZengMDPI AGInternational Journal of Molecular Sciences1422-00672019-10-012019488210.3390/ijms20194882ijms20194882Apoptotic Fragmentation of TricellulinSusanne Janke0Sonnhild Mittag1Juliane Reiche2Otmar Huber3Department of Biochemistry II, Jena University Hospital, Friedrich Schiller University Jena, 07743 Jena, GermanyDepartment of Biochemistry II, Jena University Hospital, Friedrich Schiller University Jena, 07743 Jena, GermanyDepartment of Biochemistry II, Jena University Hospital, Friedrich Schiller University Jena, 07743 Jena, GermanyDepartment of Biochemistry II, Jena University Hospital, Friedrich Schiller University Jena, 07743 Jena, GermanyApoptotic extrusion of cells from epithelial cell layers is of central importance for epithelial homeostasis. As a prerequisite cell−cell contacts between apoptotic cells and their neighbors have to be dissociated. Tricellular tight junctions (tTJs) represent specialized structures that seal polarized epithelial cells at sites where three cells meet and are characterized by the specific expression of tricellulin and angulins. Here, we specifically addressed the fate of tricellulin in apoptotic cells. Methods: Apoptosis was induced by staurosporine or camptothecin in MDCKII and RT-112 cells. The fate of tricellulin was analyzed by Western blotting and immunofluorescence microscopy. Caspase activity was inhibited by Z-VAD-FMK or Z-DEVD-FMK. Results: Induction of apoptosis induces the degradation of tricellulin with time. Aspartate residues 487 and 441 were identified as caspase cleavage-sites in the C-terminal coiled-coil domain of human tricellulin. Fragmentation of tricellulin was inhibited in the presence of caspase inhibitors or when Asp487 or Asp441 were mutated to asparagine. Deletion of the tricellulin C-terminal amino acids prevented binding to lipolysis-stimulated lipoprotein receptor (LSR)/angulin-1 and thus should impair specific localization of tricellulin to tTJs. Conclusions: Tricellulin is a substrate of caspases and its cleavage in consequence contributes to the dissolution of tTJs during apoptosis.https://www.mdpi.com/1422-0067/20/19/4882tight junctiontricellulinlipolysis-stimulated lipoprotein receptor (lsr)angulinepithelial barriercell–cell contactapoptosiscaspase |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Susanne Janke Sonnhild Mittag Juliane Reiche Otmar Huber |
spellingShingle |
Susanne Janke Sonnhild Mittag Juliane Reiche Otmar Huber Apoptotic Fragmentation of Tricellulin International Journal of Molecular Sciences tight junction tricellulin lipolysis-stimulated lipoprotein receptor (lsr) angulin epithelial barrier cell–cell contact apoptosis caspase |
author_facet |
Susanne Janke Sonnhild Mittag Juliane Reiche Otmar Huber |
author_sort |
Susanne Janke |
title |
Apoptotic Fragmentation of Tricellulin |
title_short |
Apoptotic Fragmentation of Tricellulin |
title_full |
Apoptotic Fragmentation of Tricellulin |
title_fullStr |
Apoptotic Fragmentation of Tricellulin |
title_full_unstemmed |
Apoptotic Fragmentation of Tricellulin |
title_sort |
apoptotic fragmentation of tricellulin |
publisher |
MDPI AG |
series |
International Journal of Molecular Sciences |
issn |
1422-0067 |
publishDate |
2019-10-01 |
description |
Apoptotic extrusion of cells from epithelial cell layers is of central importance for epithelial homeostasis. As a prerequisite cell−cell contacts between apoptotic cells and their neighbors have to be dissociated. Tricellular tight junctions (tTJs) represent specialized structures that seal polarized epithelial cells at sites where three cells meet and are characterized by the specific expression of tricellulin and angulins. Here, we specifically addressed the fate of tricellulin in apoptotic cells. Methods: Apoptosis was induced by staurosporine or camptothecin in MDCKII and RT-112 cells. The fate of tricellulin was analyzed by Western blotting and immunofluorescence microscopy. Caspase activity was inhibited by Z-VAD-FMK or Z-DEVD-FMK. Results: Induction of apoptosis induces the degradation of tricellulin with time. Aspartate residues 487 and 441 were identified as caspase cleavage-sites in the C-terminal coiled-coil domain of human tricellulin. Fragmentation of tricellulin was inhibited in the presence of caspase inhibitors or when Asp487 or Asp441 were mutated to asparagine. Deletion of the tricellulin C-terminal amino acids prevented binding to lipolysis-stimulated lipoprotein receptor (LSR)/angulin-1 and thus should impair specific localization of tricellulin to tTJs. Conclusions: Tricellulin is a substrate of caspases and its cleavage in consequence contributes to the dissolution of tTJs during apoptosis. |
topic |
tight junction tricellulin lipolysis-stimulated lipoprotein receptor (lsr) angulin epithelial barrier cell–cell contact apoptosis caspase |
url |
https://www.mdpi.com/1422-0067/20/19/4882 |
work_keys_str_mv |
AT susannejanke apoptoticfragmentationoftricellulin AT sonnhildmittag apoptoticfragmentationoftricellulin AT julianereiche apoptoticfragmentationoftricellulin AT otmarhuber apoptoticfragmentationoftricellulin |
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1725154250165583872 |