Ligand for members of the frizzled family of seven transmembrane receptors. Probable developmental protein. May be a signaling molecule which affects the development of discrete regions of tissues. Is likely to signal over only few cell diameters. Predominantly in neuroectodermal tissues. Undetectable in the blastula. Appears with gastrulation, is present throughout neurulation and organogenesis, and decrease to barely detectable levels in hatched larvae. Palmitoleoylation is required for efficient binding to frizzled receptors. Depalmitoleoylation leads to Wnt signaling pathway inhibition. Belongs to the Wnt family.