Activates the Hippo/SWH (Sav/Wts/Hpo) signaling pathway, a signaling pathway that plays a pivotal role in organ size control and tumor suppression by restricting proliferation and promoting apoptosis (PubMed:8269855, PubMed:20159598, PubMed:27462444, PubMed:26954546). The core of this pathway is composed of a kinase cascade wherein Hippo (Hpo), in complex with its regulatory protein Salvador (Sav), phosphorylates and activates Warts (Wts) in complex with its regulatory protein Mats, which in turn phosphorylates and inactivates the Yorkie (Yki) oncoprotein. Ex acts synergistically along with Mer and Kibra to regulate the Hippo signaling pathway (PubMed:20159598). Involved in the control of cell proliferation in imaginal disks (PubMed:8269855, PubMed:27462444). May bind to certain proteins of signal transduction pathways by interaction with their SH3 domains (PubMed:20159598). Required for apical localization of Schip1 (PubMed:26954546). Forms a complex with Kibra and Mer (PubMed:20159598). Interacts (via RXPPXY motif) with Kibra (via domain WW 1) (PubMed:20159598). Interacts with Mer and Hpo (via SARAH domain) (PubMed:20159598). Interacts with Schip1; the interaction results in recruitment of Schip1 to the apical cell membrane (PubMed:26954546). Interacts with ack and yki (PubMed:27462444). Apical surface of disk cells. Detected in wing disks (at protein level). Phosphorylated by Ack at several tyrosines including Tyr-227, Tyr-423, Tyr-679, Tyr-766 and Tyr-1103. Hyperplasia of the imaginal disk resulting in wing overgrowth (PubMed:8269855). This overgrowth is limited to specific regions along the 2 wing axes (PubMed:8269855). Defects also in eyes, head, thorax and limbs where duplication and bulging often occur (PubMed:8269855). RNAi-mediated knockdown reduces the amount of Schip1 in the apical region of the cell.