Adherens junctions (AJs), which are specialised E-cadherin-based cell contacts, are continuously remodelled during tissue morphogenesis, as cells change shape and position. The accumulation of Bazooka (Baz), the Drosophila PAR3 homologue, is thought to specify where new E-cadherin complexes are deposited during AJ remodelling, but what regulates Baz localisation? Here, Alexandre Djiane and colleagues show that the scaffold protein Magi regulates Baz localization and hence AJ remodelling in Drosophila eye epithelial cells (p. ). By studying Magi mutants, the researchers first show that Magi is required for the correct sorting of interommatidial cells during pupal eye development. They further show that Magi directly interacts with the Ras association domain protein RASSF8. This interaction, they report, is mediated by a WW domain-PPxY binding motif and is required for Magi function in the fly eye. They further demonstrate that Magi recruits a RASSF8-ASPP complex to AJs and that this, in turn, is required for the cortical recruitment of Baz to AJs during junctional remodelling. Overall, these findings highlight the importance of this novel Magi-RASSF8-ASPP complex for AJ remodelling and tissue morphogenesis.
