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 (PubMed:20018874). Functions as a upstream regulator of FGF10 expression. Plays an important role in embryonic lung development. May contribute to embryonic brain development by regulating the proliferation of dopaminergic precursors and neurons (By similarity). {ECO:0000250|UniProtKB:P21552, ECO:0000269|PubMed:20018874}. This is the function of ENSG00000105989 (WNT2, Wnt family member 2).