AUTHOR=Li Binbin, Niswander Lee A. TITLE=TMEM132A, a Novel Wnt Signaling Pathway Regulator Through Wntless (WLS) Interaction JOURNAL=Frontiers in Cell and Developmental Biology VOLUME=8 YEAR=2020 URL=https://www.frontiersin.org/articles/10.3389/fcell.2020.599890 DOI=10.3389/fcell.2020.599890 ISSN=2296-634X ABSTRACT=Wnt signaling pathway plays indispensable roles in embryonic development and adult tissue homeostasis. However, the regulatory mechanisms involved in Wnt ligand trafficking within and secretion from the signal sending cells is still relatively uncharacterized. Here, we discover a novel regulator of Wnt signaling pathway called transmembrane protein 132A (TMEM132A). Our evidence shows a physical and functional interaction of TMEM132A with the Wnt ligand transporting protein Wntless (WLS). We show that TMEM132A stabilizes Wnt ligand, enhances WLS–Wnt ligand interaction, and activates the Wnt signaling pathway. Our results shed new light on the cellular mechanism underlying the fundamental aspect of WNT secretion from Wnt signal sending cells.