[Sorting, recycling and WNT signaling: Wntless and retromer functions].

Cell-cell signaling is essential for the development of multi-cellular organisms. Indeed, membrane traffic is required for the correct sorting and function of receptors and ligands. In the past decades, many genetic screens performed in C. elegans and Drosophila have been crucial to identify the role of intracellular traffic in signaling. In this review, we discuss recent work that led to the identification of Wntless, a sorting receptor for WNT, and of the retromer, a protein complex required for the recycling of Wntless from endosomes to the trans-Golgi network.