Transmembrane Protein 88 (TMEM88)

TMEM88, a two-transmembrane-type protein. The interaction between the PDZ domain of Dvl and the C-terminal tail of TMEM88 was confirmed by using NMR and fluorescence spectroscopy. TMEM88 attenuated the Wnt/β-catenin signaling induced by Wnt-1 ligand in a dose-dependent manner, and TMEM88 knockdown by RNAi increased Wnt activity. In Xenopus, TMEM88 protein is sublocalized at the cell membrane and inhibits Wnt signaling induced by Xdsh but not β-catenin.  TMEM88 protein inhibits the formation of a secondary axis normally induced by Xdsh. TMEM88 plays a role in regulating Wnt signaling. Indeed, analysis of microarray data revealed that the expression of the Tmem88 gene was strongly correlated with that of Wnt signaling-related genes in embryonic mouse intestines. TMEM88 associates with Dvl proteins and regulates Wnt signaling in a context-dependent manner.