Regulates Wnt proteins sorting and secretion in a feedback regulatory mechanism. This reciprocal interaction plays a key role in the regulation of expression, subcellular location, binding and organelle-specific association of Wnt proteins. Also plays an important role in establishment of the anterior-posterior body axis formation during development (By similarity). Interacts with WNT3A. Interacts with WNT1, WNT3 and WNT5A. Belongs to the wntless family.