title: The Triple-Repeat Protein Anakonda Controls Epithelial Tricellular Junction Formation in Drosophila.
abstract: In epithelia, specialized tricellular junctions (TCJs) mediate cell contacts at three-cell vertices. TCJs are fundamental to epithelial biology and disease, but only a few TCJ components are known, and how they assemble at tricellular vertices is not understood. Here we describe a transmembrane protein, Anakonda (Aka), which localizes to TCJs and is essential for the formation of tricellular, but not bicellular, junctions in Drosophila. Loss of Aka causes epithelial barrier defects associated with irregular TCJ structure and geometry, suggesting that Aka organizes cell corners. Aka is necessary and sufficient for accumulation of Gliotactin at TCJs, suggesting that Aka initiates TCJ assembly by recruiting other proteins to tricellular vertices. Aka's extracellular domain has an unusual tripartite repeat structure that may mediate self-assembly, directed by the geometry of tricellular vertices. Conversely, Aka's cytoplasmic tail is dispensable for TCJ localization. Thus, extracellular interactions, rather than TCJ-directed intracellular transport, appear to mediate TCJ assembly.
authors.affiliation: Institute of Biomedicine, University of Gothenburg, Medicinaregatan 9A, 40530 Gothenburg, Sweden.
authors.forename: Sunitha
authors.initials: S
authors.lastname: Byri
authors.affiliation: Institute of Molecular Life Sciences, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: Tvisha
authors.initials: T
authors.lastname: Misra
authors.affiliation: Institute of Biomedicine, University of Gothenburg, Medicinaregatan 9A, 40530 Gothenburg, Sweden.
authors.forename: Zulfeqhar A
authors.initials: ZA
authors.lastname: Syed
authors.affiliation: Institute of Molecular Life Sciences, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: Tilmann
authors.initials: T
authors.lastname: Bätz
authors.affiliation: Institute of Molecular Life Sciences, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: Jimit
authors.initials: J
authors.lastname: Shah
authors.affiliation: Institute of Molecular Life Sciences, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Boril
authors.affiliation: Institute of Molecular Life Sciences, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: Jade
authors.initials: J
authors.lastname: Glashauser
authors.affiliation: Institute of Molecular Life Sciences, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: Tinri
authors.initials: T
authors.lastname: Aegerter-Wilmsen
authors.affiliation: Institute of Neurobiology, University of Münster, Badestrasse 9, 48149 Münster, Germany; Cluster of Excellence EXC 1003, Cells in Motion, CiM, 48149 Münster, Germany.
authors.forename: Till
authors.initials: T
authors.lastname: Matzat
authors.affiliation: Interfaculty Institute for Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany.
authors.forename: Bernard
authors.initials: B
authors.lastname: Moussian
authors.affiliation: Institute of Biomedicine, University of Gothenburg, Medicinaregatan 9A, 40530 Gothenburg, Sweden. Electronic address: anne.uv@gu.se.
authors.forename: Anne
authors.initials: A
authors.lastname: Uv
authors.affiliation: Institute of Neurobiology, University of Münster, Badestrasse 9, 48149 Münster, Germany; Cluster of Excellence EXC 1003, Cells in Motion, CiM, 48149 Münster, Germany; Institute of Molecular Life Sciences, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland. Electronic address: luschnig@uni-muenster.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Luschnig
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology* / Q000378:metabolism; D004848:Epithelium / Q000254:growth & development* / Q000378:metabolism; D015151:Immunoblotting; D007365:Intercellular Junctions / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D020449:Repetitive Sequences, Amino Acid; D019108:Tight Junctions / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C094064:gliotactin