My laboratory seeks to understand how human cells sense hormones, growth factors, and stress and how they integrate and transduce these signals to make decisions to polarize, move, or divide. We investigate these cellular regulatory systems by identifying the key signaling components and measuring when and where signaling occurs as we watch cells decide to move forward or enter the cell cycle. We have been intrigued by the near universal importance of locally-acting Ca2+ and phosphoinositide lipid second messenger signals, Rho and Ras family small GTPases, and protein kinases in controlling these decision processes. Our projects are focused on understanding the general principles of how signal transduction systems work, which often requires the development of new experimental and analysis tools involving fluorescent microscopy, small molecule and light perturbations, systematic siRNA screens, bioinformatics, genomics, and quantitative modeling of signaling pathways.