Ligand for members of the frizzled family of seven transmembrane receptors. Can activate or inhibit canonical Wnt signaling, depending on receptor context (By similarity). Plays a role in normal embryonic development (PubMed:8275867). Found primarily in ectoderm with lower levels of expression in mesoderm. Detected in the head and tail with lower expression in the middle of the embryo. No expression was found in the notochord. Present in oocytes. Levels decrease during early embryo development and then increase considerably in neurula and tadpole stages. Palmitoleoylation is required for efficient binding to frizzled receptors. Depalmitoleoylation leads to Wnt signaling pathway inhibition. Belongs to the Wnt family.