Cooperates with insulin-like peptides to stimulate the proliferation, polarization and motility of imaginal disk cells. May act by stabilizing the binding of insulin-like peptides to its receptor through a simultaneous interaction with both molecules to form a multiprotein signaling complex (By similarity). Glycosylated. Lacks the typical Glu active site in position 154 that is replaced by a Gln residue, preventing the hydrolase activity. Its precise function remains unclear. Belongs to the glycosyl hydrolase 18 family. IDGF subfamily.