The vesicle, shown in green, arrives at the active zone, shown in purple. Docking the vesicle to the presynaptic membrane involves the cooperation of many specialized proteins. Some of these proteins are found in the wall of the vesicle, some in the presynaptic membrane, and some in the cytoplasm between the two membranes. Interactions between these proteins bring the vesicle very close to the presynaptic membrane.