Helping Wingless take flight: how WNT proteins are secreted

Abstract

Recent studies have identified some of the factors that are involved in WNT secretion and have brought the focus of WNT research to the issue of how WNT proteins are secreted. What are the possible mechanisms that underlie this process? How functional WNT proteins are made and how their secretion is regulated is becoming a focal point for the WNT-signalling field. Recently, lipoprotein particles, WNT lipid modifications, the conserved transmembrane protein Wntless (WLS; also known as EVI and SRT) and the retromer complex have been implicated in WNT secretion. Our aim is to synthesize ideas from these new findings for the mechanisms that underlie WNT secretion.