The C2A domain regulates the fusion step of synaptic vesicle exocytosis. The vesicles eventually fuse with the lysosome whereupon the vesicle contents are digested. With larger vesicles and thicker vesicle walls, scoria sinks rapidly. Amphetamine enantiomers are also substrates for a specific neuronal synaptic vesicle uptake transporter called VMAT2. Myosin V is involved in vesicle and organelle transport. AP180 is used in synaptic vesicle formation. Tetanus toxin is then internalized again via endocytosis, this time in an acidic vesicle. A liposome is a spherical vesicle having at least one lipid bilayer. The first step after endocytosis is the acidification of the endocytotic vesicle. This is due to depletion of synaptic vesicle contents. These viruses are nonlytic and form virions characterized by a lipid vesicle enclosing the genome. The ingested particle becomes trapped within a pouch, known as a vesicle, inside the cytoplasm. This marker corresponds with the proteins on the vesicle traveling to the membrane. With the hydrophobic patches exposed, the toxin is able to slide into the vesicle membrane. Pericytes are responsible for tight junction formation and vesicle trafficking amongst endothelial cells.