Membrane targeting of palmitoylated Wnt and Hedgehog revealed by chemical probes

Palmitoylation of the Wnt and Hedgehog proteins is critical for maintaining their physiological functions. To date, there are no reported studies that characterize the cellular distribution of the palmitoylated forms of these proteins. Here, we describe the subcellular localization of palmitoylated Wnt and Sonic Hedgehog by using a highly sensitive and non-radioactive labeling method that utilizes alkynyl palmitic acid. We show that palmitoylated Wnt and Sonic Hedgehog localize to cellular membrane fractions only, highlighting a role for palmitoylation in the membrane association of these proteins. The method described herein has the utility to validate inhibitors of Wnt and Hedgehog acyltransferases in drug discovery, and enables further investigations of the role of palmitoylation in the secretion and signaling of these proteins.