Key regulator of the Wnt signaling pathway that mediates lipid modification of Wnt proteins. Acts as a protein-serine O-palmitoleoyltransferase that catalyzes the attachment of palmitoleate, a 16-carbon monounsaturated fatty acid (C16:1(9Z)), to Wnt proteins. Serine palmitoleoylation of WNT proteins is required for efficient binding to frizzled receptors. Has a role in cell specification, specifically in blastomere signaling. Involved in cytosketetal polarity. Required for the orientation of mitotic spindle axis