The broad objective of our research program is to define the molecular basis of GTPase function in membrane transport through the secretory pathway of eukaryotic cells.
Movement involves the activity of both anterograde and retrograde transport vesicles.
These vesicles maintain a balance of membrane flow between organelles and recycle integral membrane components of the transport machinery. Vesicle-mediated transport is regulated by a diverse group of small GTPases that belong to the Ras superfamily. Transport through the secretory pathway involves a selective mechanism in which cargo molecules are concentrated into vesicles and resident proteins are excluded. Current evidence suggests that cargo may function as ligands to initiate a signal transduction pathway that leads to the assembly of vesicle coat complexes. Linked to each cargo sorting event is the activation of a GTPase to the GTP-bound form, thereby kinetically regulating the sequential and specific recruitment of coat components to membranes.