Structural basis for the Rho- and phosphoinositide-dependent localization of the exocyst subunit Sec3

The Sec3 subunit of the yeast exocyst complex tethers secretory vesicles to the plasma membrane for exocytosis through interactions with a small GTPase and PtdIns(4,5)P2 in the target membrane. A new study describes the crystal structure of the N-terminal Rho1/Cdc42- and PtdIns(4,5)P2-binding domain of Sec3 in complex with Rho1.