title: Scribble is required for normal epithelial cell-cell contacts and lumen morphogenesis in the mammalian lung.
abstract: During lung development, proper epithelial cell arrangements are critical for the formation of an arborized network of tubes. Each tube requires a lumen, the diameter of which must be tightly regulated to enable optimal lung function. Lung branching and lumen morphogenesis require close epithelial cell-cell contacts that are maintained as a result of adherens junctions, tight junctions and by intact apical-basal (A/B) polarity. However, the molecular mechanisms that maintain epithelial cohesion and lumen diameter in the mammalian lung are unknown. Here we show that Scribble, a protein implicated in planar cell polarity (PCP) signalling, is necessary for normal lung morphogenesis. Lungs of the Scrib mouse mutant Circletail (Crc) are abnormally shaped with fewer airways, and these airways often lack a visible, 'open' lumen. Mechanistically we show that Scrib genetically interacts with the core PCP gene Vangl2 in the developing lung and that the distribution of PCP pathway proteins and Rho mediated cytoskeletal modification is perturbed in Scrib(Crc/Crc) lungs. However A/B polarity, which is disrupted in Drosophila Scrib mutants, is largely unaffected. Notably, we find that Scrib mediates functions not attributed to other PCP proteins in the lung. Specifically, Scrib localises to both adherens and tight junctions of lung epithelia and knockdown of Scrib in lung explants and organotypic cultures leads to reduced cohesion of lung epithelial cells. Live imaging of Scrib knockdown lungs shows that Scrib does not affect bud bifurcation, as previously shown for the PCP protein Celsr1, but is required to maintain epithelial cohesion. To understand the mechanism leading to reduced cell-cell association, we show that Scrib associates with β-catenin in embryonic lung and the sub-cellular distribution of adherens and tight junction proteins is perturbed in mutant lung epithelia. Our data reveal that Scrib is required for normal lung epithelial organisation and lumen morphogenesis by maintaining cell-cell contacts. Thus we reveal novel and important roles for Scrib in lung development operating via the PCP pathway, and in regulating junctional complexes and cell cohesion.
authors.affiliation: Mammalian Genetics Unit, Medical Research Council, Harwell, UK.
authors.forename: Laura L
authors.initials: LL
authors.lastname: Yates
authors.forename: Carsten
authors.initials: C
authors.lastname: Schnatwinkel
authors.forename: Lee
authors.initials: L
authors.lastname: Hazelwood
authors.forename: Lauren
authors.initials: L
authors.lastname: Chessum
authors.forename: Anju
authors.initials: A
authors.lastname: Paudyal
authors.forename: Helen
authors.initials: H
authors.lastname: Hilton
authors.forename: M Rosario
authors.initials: MR
authors.lastname: Romero
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wilde
authors.forename: Debora
authors.initials: D
authors.lastname: Bogani
authors.forename: Jeremy
authors.initials: J
authors.lastname: Sanderson
authors.forename: Caroline
authors.initials: C
authors.lastname: Formstone
authors.forename: Jennifer N
authors.initials: JN
authors.lastname: Murdoch
authors.forename: Lee A
authors.initials: LA
authors.lastname: Niswander
authors.forename: Andy
authors.initials: A
authors.lastname: Greenfield
authors.forename: Charlotte H
authors.initials: CH
authors.lastname: Dean
mesh_terms: D022005:Adherens Junctions / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D002450:Cell Communication / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D016764:Cell Polarity / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D004848:Epithelium / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D055785:Gene Knockdown Techniques; D021621:Imaging, Three-Dimensional; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008168:Lung / Q000166:cytology* / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D008322:Mammals / Q000196:embryology*; D051379:Mice; D008954:Models, Biological; D009024:Morphogenesis / Q000187:drug effects; D060172:Morpholinos / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism; D062827:Zonula Occludens-2 Protein / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D060172:Morpholinos; D009419:Nerve Tissue Proteins; D043562:Receptors, G-Protein-Coupled; D062827:Zonula Occludens-2 Protein; D051176:beta Catenin; D020742:rhoA GTP-Binding Protein; C117380:Celsr1 protein, mouse; C431577:Ltap protein, mouse; C508433:scrib protein, mouse