Insulin regulates the storage of dietary glucose by stimulating glucose uptake into muscle and fat cells. Insulin increases glucose uptake into these cells by recruiting vesicles containing the Glut4 glucose transporter to the cell surface. Thus, insulin controls glucose uptake by regulating Glut4 trafficking between the interior and cell surface. Understanding how insulin regulates Glut4 traffic is key for understanding the molecular changes underlying type 2 diabetes.

We use quantitative optical microscopy to study insulin-regulated membrane trafficking. Some of the main objectives of our work are to characterize the Glut4 trafficking pathway in the presence and absence of insulin, to identify how the insulin-signal transduction regulates the movement of Glut4 vesicles, and to understand how other hormones control the tone of insulin response. The ultimate objective is to translate what we learn at the subcellular and cellular levels to a better understanding of whole-body insulin action and glucose metabolism. In addition to studies of Glut4 trafficking, we are also interested in applying cell biological and imaging methods to understand the role of the tumor microenvironment in human lung cancer.