Ligand for members of the frizzled family of seven transmembrane receptors. Probable developmental protein. May be a signaling molecule which affects the development of discrete regions of tissues. Is likely to signal over only few cell diameters. Binds receptor tyrosine kinase cam-1 (PubMed:17942487). Together with Wnt ligand cwn-2, regulates the migration of CAN, ALM, BDU and HSN neurons during embryogenesis, the migration of QL and QR neuroblast descendants during larval development, and polarity of ALM neurons (PubMed:16109397, PubMed:16516839, PubMed:18622031, PubMed:25917219). Also acts with the Wnt ligand egl-20 to direct HSN neuron migration (PubMed:16516839). Acts through the Wnt receptor cfz-2 to direct ALM migration (PubMed:16109397). Also plays a role in axon growth and guidance in HSN and male CP neurons (PubMed:16109397). In addition, together with Wnt ligand cwn-2, negatively regulates developmental neurite pruning of AIM neurons probably by acting as a ligand for receptor tyrosine kinase cam-1 (PubMed:19561603). Probably by activating the Wnt/Frizzled pathway, may regulate vulva development (PubMed:17942487). May act redundantly with other Wnt ligands such as cwn-2 and mom-2 to control seam cell polarity (PubMed:22022276). Expressed in intestine, some head neurons and ventral nerve cord and pharyngeal neurons (PubMed:19561603). Expressed in the tail and weakly expressed in the vulva and body wall muscles (PubMed:20711352). Expressed highly in posterior dorsal and ventral muscle cells (PubMed:22022276). Detected in all larval forms and adults, but is most abundant in the embryonic stage (PubMed:8510930). First expressed in the embryonic tail at the comma stage of embryogenesis (PubMed:16516839). In newly hatched larvae, it is expressed in four stripes of cells lining the dorsal and ventral posterior quadrants of the body (PubMed:16516839). Expression spreads anteriorly becoming restricted to the ventral side of the body as development progresses (PubMed:16516839). Palmitoleoylation is required for efficient binding to frizzled receptors. Depalmitoleoylation leads to Wnt signaling pathway inhibition. Defective ALM, BDU and QR neuroblast migration and irregular HSN and CP axon growth and guidance (PubMed:16109397). Double knockout with cwn-2 results in ALM and CAN migration defects (PubMed:16109397). Double knockout with either cwn-2 or egl-20 results in HSN migration defects (PubMed:16516839). Triple knockout with cwn-2 and cfz-2 results in enhanced neuronal cell migratory defects (PubMed:16109397). Belongs to the Wnt family.