Imagine the chaos on the streets if there were no road signs or lights to coordinate traffic. Cells also have traffic routes for transferring molecular cargo to-and-from specific membrane destinations within their interior. However, without some way to coordinate the cellular traffic of lipids and proteins within cells, gridlock would result and growth would come to a standstill. Our research focuses on two important questions about membrane transport within cells: (i) what are the critical molecular parts needed for these transport machines to work; (ii) is there a cellular regulator that coordinates the movement of all these different transport machines? Using Saccharomyces cerevisiae (budding yeast) as a living test tube, our research has identified mechanisms for how sterols like cholesterol are transferred from inside the cell to its outer membrane. We have also discovered a regulatory mechanism that integrates the transport cycle of membrane proteins going to-and-from the cell surface. Through our research we are answering fundamental questions about the dynamics of cell growth, which has direct implications for human health and combating disease.