Component of the Fat (ft) signaling pathway that functions in normal development of various organs such as the wing and leg (PubMed:19710173, PubMed:21379328). In developing imaginal disks, involved in regulating both the protein levels and apical localization of ft and ds (PubMed:19710173). Involved in establishing planar cell polarity (PCP) along the anterior-posterior axis of the wing (the early Fz signaling event), probably by acting upstream of ds and ft to regulate Fz activity (PubMed:21379328). Interacts with ft (via intracellular domain) and ds (via intracellular domain). In wing imaginal disks, strong cytoplasmic expression in the wing pouch but in regions of the wing hinge preferentially expressed in the sub-apical membrane. Broadly expressed in the developing imaginal disks including the wing, leg and eye, and the neuroepithelium of the optic lobes of the brain. In the eye imaginal disk, expression is highest in the morphogenetic furrow and in the wing imaginal disk it is highest near the dorsal-ventral (DV) compartment boundary. Viable and fertile. Wings are slightly shorter with a decreased distance between cross-veins. Belongs to the LIX1 family.