Interplay of MPP5a with Rab11 synergistically builds epithelial apical polarity and zonula adherens.

Adherens junctions remodeling regulated by apical polarity proteins constitutes a major driving force for tissue morphogenesis, though the precise mechanism remains inconclusive. Here we reported that Crumbs complex component MPP5a interacts with small GTPase Rab11 in Golgi to synergistically transport cadherin and Crumbs components to the apical domain, thus establishing the apical epithelial polarity and adherens junctions. In contrast, Par complex recruited by MPP5a is incapable to interact with Rab11 but may assemble cytoskeleton to facilitate the cadherin exocytosis. In accordance, dysfunction of MPP5a induced an invasive migration of epithelial cells. This adherens junctions remodeling pattern is frequently observed in zebrafish lens epithelial cells and neuroepithelial cells. The data identified an unrecognized MPP5a/Rab11 complex and described its essential role in guiding the apical polarization and zonula adherens formation in epithelial cells.