Ligand for members of the frizzled family of seven transmembrane receptors. Can activate or inhibit canonical Wnt signaling, depending on receptor context. Required during embryogenesis for extension of the primary anterior-posterior axis. Neuroectodermal and non-neuroectodermal tissues. Abundant in the blastula until gastrulation, barely detectable during gastrulation, and increase again during neurulation. Detected throughout the remaining development and in hatched larvae. Palmitoleoylation is required for efficient binding to frizzled receptors. Depalmitoleoylation leads to Wnt signaling pathway inhibition. Belongs to the Wnt family.