Coordination of tissue homeostasis and growth by the Scribble-alpha-Catenin-Septate junction complex

Maintaining apicobasal polarity (ABP) is crucial for epithelial integrity and homeostasis during tissue development. Although intracellular mechanisms underlying ABP establishment have been well studied, it remains to be addressed how the ABP coordinates tissue growth and homeostasis. By studying Scribble, a key ABP determinant, we address molecular mechanisms underlying ABP-mediated growth control in the Drosophila wing imaginal disc. Our data reveal that genetic and physical interactions between Scribble, Septate junction complex and alpha-Catenin appear to be key for sustaining ABP-mediated growth control. Cells with conditional scribble knockdown instigate the loss of alpha-Catenin, ultimately leading to the formation of neoplasia accompanying with activation of Yorkie. In contrast, cells expressing wild type scribble progressively restore ABP in scribble hypomorphic mutant cells in a non-autonomous manner. Our findings provide unique insights into cellular communication among optimal and sub-optimal cells to regulate epithelial homeostasis and growth.