title: Epithelial tricellular junctions act as interphase cell shape sensors to orient mitosis.
abstract: The orientation of cell division along the long axis of the interphase cell--the century-old Hertwig's rule--has profound roles in tissue proliferation, morphogenesis, architecture and mechanics. In epithelial tissues, the shape of the interphase cell is influenced by cell adhesion, mechanical stress, neighbour topology, and planar polarity pathways. At mitosis, epithelial cells usually adopt a rounded shape to ensure faithful chromosome segregation and to promote morphogenesis. The mechanisms underlying interphase cell shape sensing in tissues are therefore unknown. Here we show that in Drosophila epithelia, tricellular junctions (TCJs) localize force generators, pulling on astral microtubules and orienting cell division via the Dynein-associated protein Mud independently of the classical Pins/Gαi pathway. Moreover, as cells round up during mitosis, TCJs serve as spatial landmarks, encoding information about interphase cell shape anisotropy to orient division in the rounded mitotic cell. Finally, experimental and simulation data show that shape and mechanical strain sensing by the TCJs emerge from a general geometric property of TCJ distributions in epithelial tissues. Thus, in addition to their function as epithelial barrier structures, TCJs serve as polarity cues promoting geometry and mechanical sensing in epithelial tissues.
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Floris
authors.initials: F
authors.lastname: Bosveld
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Olga
authors.initials: O
authors.lastname: Markova
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Boris
authors.initials: B
authors.lastname: Guirao
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Martin
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Institut Jacques Monod, CNRS UMR7592 15 rue Hélène Brion, 75205 Paris Cedex 13, France.
authors.forename: Anaëlle
authors.initials: A
authors.lastname: Pierre
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Maria
authors.initials: M
authors.lastname: Balakireva
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Gaugue
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Anna
authors.initials: A
authors.lastname: Ainslie
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Christophorou
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.|Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA.
authors.forename: David K
authors.initials: DK
authors.lastname: Lubensky
authors.affiliation: Institut Jacques Monod, CNRS UMR7592 15 rue Hélène Brion, 75205 Paris Cedex 13, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Minc
authors.affiliation: Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Yohanns
authors.initials: Y
authors.lastname: Bellaïche
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins; D016764:Cell Polarity; D048430:Cell Shape; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology*; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D005260:Female; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000378:metabolism; D007365:Intercellular Junctions; D007399:Interphase; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D009419:Nerve Tissue Proteins / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D020730:Guanine Nucleotide Dissociation Inhibitors; D008565:Membrane Proteins; C411670:Mud protein, Drosophila; D009419:Nerve Tissue Proteins; C405164:Pins protein, Drosophila; D019206:GTP-Binding Protein alpha Subunits, Gi-Go