Ligand for members of the frizzled family of seven transmembrane receptors (Probable). Functions in the canonical Wnt signaling pathway that results in activation of transcription factors of the TCF/LEF family (PubMed:26902720). Required for normal gastrulation, formation of the primitive streak, and for the formation of the mesoderm during early embryogenesis. Required for normal formation of the apical ectodermal ridge (By similarity). Required for normal embryonic development, and especially for limb development (PubMed:14872406). Forms a soluble 1:1 complex with AFM; this prevents oligomerization and is required for prolonged biological activity (PubMed:26902720). The complex with AFM may represent the physiological form in body fluids (PubMed:26902720).Interacts with PORCN. Interacts with WLS (By similarity). Palmitoleoylation is required for efficient binding to frizzled receptors. Depalmitoleoylation leads to Wnt signaling pathway inhibition. The disease is caused by variants affecting the gene represented in this entry. Belongs to the Wnt family.