Protein-serine O-palmitoleoyltransferase that acts as a key regulator of the Wnt signaling pathway by mediating the attachment of palmitoleate, a 16-carbon monounsaturated fatty acid (C16:1), to Wnt proteins. Serine palmitoleylation of Wnt proteins is required for efficient binding to frizzled receptors (By similarity). Also facilitates the glycosylation of Wnt family members, including wg and Wnt5. The cotranslational disulfide bond formation of wg competes with the N-glycosylation. Porc stimulates the post-translational N-glycosylation by anchoring wg at the ER membrane, probably through acylation (PubMed:11821428, PubMed:15166250, PubMed:22108505, PubMed:8985181). (9Z)-hexadecenoyl-CoA + [Wnt protein]-L-serine = [Wnt protein]-O-(9Z)-hexadecenoyl-L-serine + CoA Interacts with wg and Wnt5. Expressed both maternally and zygotically. Belongs to the membrane-bound acyltransferase family. Porcupine subfamily. Was initially thought to mediate palmitoylation of Wnt proteins. It was later shown that it instead acts as a serine O-palmitoleoyltransferase that mediates the attachment of palmitoleate, a 16-carbon monounsaturated fatty acid (C16:1), to Wnt proteins.