Interplay between Anakonda, Gliotactin, and M6 for Tricellular Junction Assembly and Anchoring of Septate Junctions in Drosophila Epithelium.

Autor:	Esmangart de Bournonville T; Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes), UMR 6290, 2 Avenue du Professeur Leon Bernard, 35000 Rennes, France; Equipe Labellisée Ligue Nationale contre le Cancer, 14 Rue Corvisart, 75013 Paris, France., Le Borgne R; Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes), UMR 6290, 2 Avenue du Professeur Leon Bernard, 35000 Rennes, France; Equipe Labellisée Ligue Nationale contre le Cancer, 14 Rue Corvisart, 75013 Paris, France. Electronic address: roland.leborgne@univ-rennes1.fr.
Jazyk:	angličtina
Zdroj:	Current biology : CB [Curr Biol] 2020 Nov 02; Vol. 30 (21), pp. 4245-4253.e4. Date of Electronic Publication: 2020 Aug 27.
DOI:	10.1016/j.cub.2020.07.090
Abstrakt:	In epithelia, tricellular junctions (TCJs) serve as pivotal sites for barrier function and integration of both biochemical and mechanical signals [1-3]. In Drosophila, TCJs are composed of the transmembrane protein Sidekick at the adherens junction (AJ) level, which plays a role in cell-cell contact rearrangement [4-6]. At the septate junction (SJ) level, TCJs are formed by Gliotactin (Gli) [7], Anakonda (Aka) [8, 9], and the Myelin proteolipid protein (PLP) M6 [10, 11]. Despite previous data on TCJ organization [12-14], TCJ assembly, composition, and links to adjacent bicellular junctions (BCJs) remain poorly understood. Here, we have characterized the making of TCJs within the plane of adherens junctions (tricellular adherens junction [tAJ]) and the plane of septate junctions (tricellular septate junction [tSJ]) and report that their assembly is independent of each other. Aka and M6, whose localizations are interdependent, act upstream to localize Gli. In turn, Gli stabilizes Aka at tSJ. Moreover, tSJ components are not only essential at vertex, as we found that loss of tSJ integrity induces micron-length bicellular SJ (bSJ) deformations. This phenotype is associated with the disappearance of SJ components at tricellular contacts, indicating that bSJs are no longer connected to tSJs. Reciprocally, SJ components are required to restrict the localization of Aka and Gli at vertex. We propose that tSJs function as pillars to anchor bSJs to ensure the maintenance of tissue integrity in Drosophila proliferative epithelia. Competing Interests: Declaration of Interests The authors declare no competing interests. (Copyright © 2020 Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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