Research in my laboratory focuses on the dysregulation of intracellular protein trafficking events that occur in cancer and neurodegenerative disease. Protein transport studies were initiated in yeast and the insights gained from the yeast system have been applied to trafficking events that occur in mammalian cells. Our current work centers on activators of the Rab5/Vps21p family of small GTPases. In mammalian cells, Rab5 plays a critical role in regulating movement of cell surface receptors through the early stages of the endocytic pathway. We have identified a family of proteins that integrate Rab5 activation with several cell signaling cascades and are currently dissecting the role these proteins play in regulating cell surface receptor trafficking and cell signaling in normal and disease states.