%0 Journal Article %A Aguilar-Aragon, Mario %A Bonello, Teresa T %A Bell, Graham P %A Fletcher, Georgina C %A Thompson, Barry J %D 2020 %T Adherens junction remodelling during mitotic rounding of pseudostratified epithelial cells. %U https://crick.figshare.com/articles/journal_contribution/Adherens_junction_remodelling_during_mitotic_rounding_of_pseudostratified_epithelial_cells_/12464681 %2 https://crick.figshare.com/ndownloader/files/23085875 %K E-cadherin %K cortex %K mitosis %K myosin %K Thompson FC001180 %K 0601 Biochemistry and Cell Biology %K Developmental Biology %X Epithelial cells undergo cortical rounding at the onset of mitosis to enable spindle orientation in the plane of the epithelium. In cuboidal epithelia in culture, the adherens junction protein E-cadherin recruits Pins/LGN/GPSM2 and Mud/NuMA to orient the mitotic spindle. In the pseudostratified columnar epithelial cells of Drosophila, septate junctions recruit Mud/NuMA to orient the spindle, while Pins/LGN/GPSM2 is surprisingly dispensable. We show that these pseudostratified epithelial cells downregulate E-cadherin as they round up for mitosis. Preventing cortical rounding by inhibiting Rho-kinase-mediated actomyosin contractility blocks downregulation of E-cadherin during mitosis. Mitotic activation of Rho-kinase depends on the RhoGEF ECT2/Pebble and its binding partners RacGAP1/MgcRacGAP/CYK4/Tum and MKLP1/KIF23/ZEN4/Pav. Cell cycle control of these Rho activators is mediated by the Aurora A and B kinases, which act redundantly during mitotic rounding. Thus, in Drosophila pseudostratified epithelia, disruption of adherens junctions during mitosis necessitates planar spindle orientation by septate junctions to maintain epithelial integrity. %I The Francis Crick Institute