David Ernest James (born in Sydney in 1958) is a cell biologist who discovered the glucose transporter GLUT4. He has also been responsible for the molecular dissection of the intracellular trafficking pathways that regulate GLUT4 translocation to the cell surface, the topological mapping of the insulin signal transduction pathway, the creation of a method for studying in vivo metabolism in small animals, and the use of this method to gain insights into whole-animal fuel metabolism and homeostasis.