Fig. 6.

Model of Ouabain blocking the Na,K-ATPase pump and macropinocytosis, resulting in inhibition of Wnt signaling. The Na,K-ATPase transmembrane protein is a member of the P-type ATPase family that pumps three Na⁺ ions out of cells while pumping two K⁺ ions into cells, establishing the electrical potential across membranes. The cardiotonic steroid Ouabain is a selective Na,K-ATPase inhibitor targeting the α1-subunit that blocks macropinocytosis, lysosomes, and Wnt signaling.