Secretion of Wnt proteins

Secretion of Wnt proteins

 

Upon translation, Wnt proteins (yellow ovals) undergo a series of modifications as they transit through the secretory pathway and associate with several proteins, including Porcupine (Porc)  in the endoplasmic reticulum. All Wnt proteins harbor a covalent lipid modification: a palmitate, attached by the palmitoyltransferase Porcupine. The transmembrane protein Wntless (Wls) exclusively binds to lipidated Wnt proteins and transfers them to the plasma membrane for secretion.  Once secreted, Wnt proteins may be incorporated into secretory vesicles wherein Wls continues to bind Wnt proteins, perhaps  presenting lipidated Wnt proteins to their cognate Frizzled receptors.Wnt secretion