Ligand for members of the frizzled family of seven transmembrane receptors (Probable). Acts in the canonical Wnt signaling pathway by promoting beta-catenin-dependent transcriptional activation (PubMed:25451226). Developmental protein that promotes cell proliferation in the developing spinal cord (PubMed:25451226). Has a role in osteoblast function, bone development and bone homeostasis (By similarity). Forms a soluble 1:1 complex with AFM; this prevents oligomerization and is required for prolonged biological activity. The complex with AFM may represent the physiological form in body fluids (By similarity). Interacts with PORCN (PubMed:25451226). Expression in the met-mesencephalic region. N-glycosylated. N-glycosylation favors subsequent palmitoleoylation. Palmitoleoylation is required for efficient binding to frizzled receptors. Palmitoleoylation is necessary for proper trafficking to cell surface (Probable). Depalmitoleoylated by NOTUM, leading to inhibit Wnt signaling pathway (By similarity). Belongs to the Wnt family. A palmitoylation site was proposed at Cys-91, but it was later shown that this cysteine is engaged in a disulfide bond.