Daam1 regulates the endocytosis of EphB during the convergent extension of the zebrafish notochord

Convergent extension (CE) movement of cells is one of the fundamental processes that control the organized morphogenesis of tissues and organs. The molecular events connecting the noncanonical Writ pathway and CE movement, however, are not well understood. We show that subcellular localization of Daaml, an essential component of noncanonical Writ signaling, changes dynamically during notochord formation. In the early phases, Daaml complexes with EphB receptors and Disheveled 2. This complex is incorporated into endocytic vesicles in a dynamin-dependent manner, thereby resulting in the removal of EphB from the cell surface with subsequent switching of cell adhesiveness. In the next step, Daaml colocalizes with the actin cytoskeleton to induce morphological extension of cells. We elucidate the molecular mechanism underlying the CE movement of notochord cells with Daaml as a dynamic coordinator of enclocytosis and cytoskeletal remodeling.