Ligand for members of the frizzled family of seven transmembrane receptors. Functions in the canonical Wnt signaling pathway that results in activation of transcription factors of the TCF/LEF family. Required for normal embryonic mesoderm development and formation of caudal somites. Required for normal morphogenesis of the developing neural tube. Disulfide bonds have critical and distinct roles in secretion and activity. Loss of each conserved cysteine results in high molecular weight oxidized Wnt oligomers, which are formed through inter-Wnt disulfide bonding. Palmitoleoylation is required for efficient binding to frizzled receptors. Depalmitoleoylation leads to Wnt signaling pathway inhibition. Belongs to the Wnt family.