title: A functional role of the extracellular domain of Crumbs in cell architecture and apicobasal polarity.
abstract: Regulated cell shape changes in epithelial cells, which contribute to most organs and tissues, are at the basis of morphogenesis. Crumbs (Crb) is an essential apical determinant controlling epithelial apicobasal polarity. Here we provide evidence for a novel role of Crb apical localisation and stabilisation in controlling cell shape through apical domain organisation and adherens junction positioning. We find that Crb apical stabilisation requires the extracellular domain. In vivo results from Drosophila suggest that the extracellular domain assists Crb apical stabilisation by mediating Crb-Crb interactions at opposing cell membranes. We further confirm Crb-Crb extracellular interactions by showing that the extracellular domain of Crb is sufficient to promote cell aggregation in vitro. Furthermore, we report that Crb apical stabilisation mediated by the extracellular domain is also required for maintenance of Crb apicobasal polarity. Our results provide new insights into the mechanisms of apicobasal polarity and the cellular mechanisms of tissue architecture.
authors.affiliation: Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac, 10-12, 08028 Barcelona, Spain.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Letizia
authors.forename: Sara
authors.initials: S
authors.lastname: Ricardo
authors.forename: Bernard
authors.initials: B
authors.lastname: Moussian
authors.forename: Nicolás
authors.initials: N
authors.lastname: Martín
authors.forename: Marta
authors.initials: M
authors.lastname: Llimargas
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism*; D000818:Animals; D030801:Animals, Genetically Modified; D016764:Cell Polarity; D048430:Cell Shape / Q000235:genetics; D002478:Cells, Cultured; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000254:growth & development*; D004847:Epithelial Cells / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009024:Morphogenesis; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics
chemical_list: D029721:Drosophila Proteins; D008565:Membrane Proteins; C064360:crb protein, Drosophila
keywords: Cell architecture; Crumbs; Drosophila melanogaster; Morphogenesis