The leading edge during dorsal closure as a model for epithelial plasticity: Pak is required for recruitment of the Scribble complex and septate junction formation

• DOI: 10.1242/dev.045088
• Publication Date: 2010-05-25T11:28:03Z
• Authors: Sami Bahri; Simon Wang; Ryan Conder; Juliana Choy; Stephanie Vlachos; Kevin Dong; Carlos Merino; Stephan Sigrist; Cristina Molnar; Xiaohang Yang; Edward Manser; Nicholas Harden
• Keywords: Cell polarity; CDC42; Lamellipodium; Filopodia; Epithelial polarity; Polarity (international relations)

Dorsal closure (DC) of the Drosophila embryo is a model for study wound healing and developmental epithelial fusions, involves sealing hole in epidermis through migration epidermal flanks over tissue occupying hole, amnioserosa. During DC, cells at edge migrating extend Rac- Cdc42-dependent actin-based lamellipodia filopodia from their leading (LE), which exhibits breakdown apicobasal polarity as adhesions are severed with neighbouring amnioserosa cells. Studies using mammalian have demonstrated that Scribble (Scrib), an important determinant functions protein complex, controls polarized cell recruitment Rac, Cdc42 serine/threonine kinase Pak, effector Rac Cdc42, to LE. We used DC follicular epithelium relationship between Pak Scrib complex membranes undergoing changes adhesion during development. propose that, LE membrane undergoes epithelial-to-mesenchymal-like transition initiate sheet migration, followed by mesenchymal-to-epithelial-like sheets meet up restore cell-cell adhesion. This latter event requires integrin-localized recruits septate junction formation. conclude there bidirectional interactions modulating plasticity. can recruit but, migratory up,