Plays an important role in determining body shape and sensory ray morphology, possibly by acting as a signaling molecule outside the expressing cell. Expressed in hypodermis first at the two-fold stage and throughout the larval stages but not at the adult stage. Detected in the body seams after the L4 stage with expression maintained in adults. Detected in the male tail structural cells at the late L4 stage and also maintained in adults. Detected at different developmental stages in vulva, PQR neurons and several neuronal processes in the head region. The EGF-like domain and the SXC (ShKT) domain are essential for the biological activity of the protein. May function as protein interaction domains.