My research is focused on the regulation of cell migration by signal transduction networks centered on Rho family small GTPases. I am particularly interested in understanding the control of the Rho GTPases within these networks by the much larger RhoGEF family, and how this control becomes dis-regulated in cancer and inflammation. To probe these signaling networks, I design and build fluorescent imaging tools to allow direct visualization of the activities of pathway components, including Rho GTPases and RhoGEFs, with particular emphasis on strategies that allow simultaneous visualization of multiple protein activities. In collaboration with researchers from the lab of Gaudenz Danuser, I use these tools to study feedback regulation and build causality maps of Rho GTPase and RhoGEF activities in migrating cells. With these new tools we can identify specific network connections and mechanistically link them to biological processes. I am also working on new biosensor approaches that minimize cell perturbation so that we can study low abundance molecules in GTPase circuits.