Original Con Involvement of Na+/K+-ATPase a i

asc hio ug e 25 Free Radical Biology & MedicIntroduction Na+/K+-ATPase, or sodium pump, is a ubiquitous trans-membrane enzyme that has long been ascribed the function of transporting Na+ and K+ across the plasma membrane [1,2]. Recently, we have demonstrated that Na/K-ATPase is an important signal transducer in cardiac myocytes [3–6]. Binding of ouabain to the Na+/K+-ATPase stimulates multiple pathways including activation of phospholipase C (PLC)/protein kinase C (PKC) cascade [7] and Src/EGFR/Ras/Raf/ERK1/2 cascade [8] and increased production of ROS [9]. ROS, such as the superoxide radical and H2O2, are continuously produced i