Dr. Jack Kaplan is a Benjamin Goldberg Professor in the Departments of Biochemistry and Molecular Genetics involvement with the investigation of membrane transport proteins began in studies using human red blood cells in efforts to demonstrate the relationship between the coupling of biochemical reactions and transport modes of the Na pump. These studies led to the invention of caged compounds (caged ATP, caged Pi and caged Ca) and the introduction of the photorelease approach in cellular and molecular physiology, biophysics and neurobiology. Subsequent studies of the Na pump in mammalian cells have contributed to the current understanding of its mechanism and regulation. About twelve years ago we initiated studies into Cu homeostasis in humans and published early studies on the mode of action of ATP7B, the Wilson Disease protein and one of the first structure-function and topology studies of hCTR1, the human high affinity uptake Cu transporter, utilizing heterologous expression in insect cells. This work established the membrane topology of hCTR1, and proposed a model for its action as a trimeric pore that has subsequently been confirmed in medium-resolution structures. We subsequently have moved into mammalian cell systems, where we now investigate its regulation and mechanism. In this work his lab uses cell biological, radioisotope, confocal imaging, TIRM, recombinant protein purification and antibody technologies. Their work has shed light on the mechanism of Cu uptake in human cells and its contribution to Cu regulation via regulatory endocytosis. Over those last four decades they have contributed new methods and approaches to the study of membrane transport processes that have been recognized by election as a Fellow of the Royal Society (1995), of the Biophysical Society (2000) and of AAAS (2015).