Figure 1 ARF-GEFs and vesicle formation (a) ARF GDP/GTP cycle. Cytosolic ARF-GDP is recruited to membrane by ARF-GEF mediating GDP-GTP exchange. ARF-GAP stimulated GTP hydrolysis leads to dissociation of ARF-GDP from the membrane. | Figure 2 Membrane fusion through SNARE complex formation Disassembly of the cis-SNARE complex converts the open form of syntaxin to a closed form (5), which has to be reverted before trans-SNARE complex formation (1). |