Dr. Joanne Johnson's research examines events at the molecular level that ultimately lead to cell growth. Among the events is activation of cell surface receptors by ligand molecules, which leads to generation of specialized lipids in the cell membrane. These lipids act as signals to promote membrane binding and activation of proteins. Johnson is assessing the role of Diacylglycerol (DAG), and two newly identified proteins, RasGRP and CalDAG1. Johnson is specifically investigating how DAG and other lipids influence membrane binding and activity of RasGRP and CalDAG1, which function to activate the Ras protein, a critical switch in the control of cell growth. Knowledge of this process may lead to development of specific inhibitor drugs controlling cell growth and defending against tumours.