My early research interest is bioenergetics which led to the identification of V-type proton pumps during my graduate years in late Dr. Efraim Racker’s laboratory. Since joining the faculty of UT Southwestern, I have continued the research on mammalian V-ATPases with the goal to understand the structure, function, and regulation of ATP-driven V-type proton pumps. In recent years, my research interest has expanded to enzymes that transport lipids including sterols and phospholipids, either as metabolites or cellular signals. Among these transporters, the main project in the lab is ABCG5 and ABCG8, which, as members of a superfamily of ATP-Binding-Cassette transporters, form a heterodimer and play important roles in sterol transport. The focus of our research in the present is the biochemistry and molecular characterization of ABCG5/ABCG8 transporter, aiming at understanding the mechanism by which this transport system operates to translocate cholesterol cross membranes.