Fig. 10. Dpp signaling regulates IPC morphogenesis in the Drosophila pupal retina. Dpp signaling is required to achieve correct cell-cell contacts, cell positions and cell shape during IPC patterning. This function requires the activity of DE-cadherin (Cad) and Rho1 and is opposed by Rst. This suggests that Dpp signaling acts as an intermediary or `third force' between the Rst and DE-cadherin adhesion systems, providing a point of fine and dynamic regulation of the adherens junctions during epithelial maturation. A balanced interplay between these three systems is essential to regulate IPC patterning during morphogenesis of the pupal retina. The placement of Rho1 after DE-cadherin is speculative. See text for details.