A timeline of events during yeast exocytosis. Several Myo2p motors (one is shown for simplicity) transport a vesicle to sites of exocytosis via interactions with Sec4p, the exocyst (through Sec15p), and an unknown component interacting with PI4P (shown with a question mark). Vesicle tethering via the exocyst complex physically attaches the vesicle to the cortex, which lasts for 18 s in wild-type cells. Myo2p motors are released gradually, with all dissociated ∼4 s before fusion. This may indicate that Sec4-GTP is also hydrolyzed on a continuum. Finally, the GEF Sec2p and the exocyst complex are released at the moment of vesicle fusion, which then likely breaks into vesicle-associated and plasma membrane–associated components for another round of tethering. Not shown is the recycling event of the SNARE proteins, Sec4p by GDI, or the recycling of the unknown component of the receptor complex.