<p>The process of vesicular fusion with target membranes depends on a set of SNAREs (SNAP-Receptors), which are associated with the fusing membranes [<cite idref="PUB00005793"/>, <cite idref="PUB00005792"/>]. Target SNAREs (t-SNAREs) are localised on the target membrane and belong to two different families, the syntaxin-like family and the SNAP-25 like family. One member of each family, together with av-SNARE localised on the vesicular membrane, are required for fusion. </p> <p>The Syntaxins are type-I transmembrane proteins that contain several regions with coiled-coil propensity in their cytosolic part, the SNARE motif. SNAP-25 (<db_xref db="INTERPRO" dbkey="IPR000928"/>) is a protein consisting of two coiled-coil regions, which is associated with the membrane by lipid anchors. SNARE motifs assemble into parallel four helix bundles stabilised by the burial of these hydrophobic helix faces in the bundle core. Monomeric SNARE motifs are disordered so this assembly reaction is accompanied by a dramatic increase in alpha-helical secondary structure [<cite idref="PUB00014194"/>]. The parallel arrangement of SNARE motifs within complexes bring the transmembrane anchors, and the two membranes, into close proximity. Recently, it was shown that the two coiled-coil regions of SNAP-25 andone of the coiled-coil regions of the syntaxins are related [<cite idref="PUB00005782"/>]. This domain is found in both Syntaxin and SNAP-25 families as well as in other proteins.</p> Target SNARE coiled-coil domain