Time-specific regulation of airway clearance by the Drosophila J-domain transmembrane protein Wurst

At the end of embryogenesis, Drosophila and mammalian airways convert from liquid-filled to air-filled tubes. This process is regulated by Clathrin-mediated endocytosis. However, these molecular mechanisms are poorly understood. In Drosophila, the DnaJ transmembrane protein Wurst interacts with Clathrin and Hsc70 to mediate early steps of endocytosis. Wurst is expressed in epithelial tissues from early stages onwards. Here we show time- and tissue-specific requirement of Wurst in airway liquid-clearance and air-filling. RNAi experiments demonstrate that Wurst activity is specifically required at the final stage 17 of embryogenesis. Furthermore, we show that the apical membrane organizer Crumbs regulates Wurst-mediated airway liquid-air-transition.