Regulation of Phosphatidylinositol Kinases and Metabolism by Wnt3a and Dvl

Wnt signaling plays important roles in various physiological and pathophysiological processes. The pathway that leads to β-catenin stabilization is initiated by Wnt binding to its cell surface receptors, which induces the formation of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) via activation of phosphatidylinositol 4-phosphate 5-kinase (PIP5K) type I. Here, we show that Wnt also stimulated the production of phosphatidylinositol 4-phosphate (PtdIns(4)P), which depended on Frizzled (Fz), Dishevelled (Dvl), and phosphatidylinositol 4-kinase (PI4K) type IIα in HEK293T cells. Dvl directly interacted with and activated PI4KIIα by increasing its Vmax for ATP and PtdIns. In addition, Dvl regulated PI4KIIα and PIP5KI via different domains. Moreover, Dvl, PI4KIIα, and PIP5KI appeared to form a ternary complex upon Wnt3a stimulation. This complex may allow efficient production of PtdIns(4,5)P2 from PtdIns, which is far more abundant than PtdIns(4)P in cells. Therefore, this study provides new insights into the mechanism by which Wnt3a regulates the production of PtdIns(4,5)P2.