InterPro domain: IPR044766

This entry represents the N-terminal SNARE motif found in plant SNAP25 homologues, SNAP29, SNAP30 and SNAP33 [ 1 , 2 , 3 ], and in the novel plant SNAREs (NPSNs) 11, 12 and 13 from Arabidopsis thaliana [ 4 , 4 ]. SNAP33 and NPS11 play a key role in cytokinesis [ 5 , 5 ]. SNAP33, the most studied SNAP25 homologue in Arabidopsis, is also involved in triggering innate immune responses. SNAP29 and SNAP30 have not been well-characterised yet [ 5 ].

Soluble N-ethylmaleimide attachment protein receptor (SNARE) proteins are a family of membrane-associated proteins characterised by an alpha-helical coiled-coil domain called the SNARE motif [ 5 ]. These proteins are classified as v-SNAREs and t-SNAREs based on their localisation on vesicle or target membrane; another classification scheme defines R-SNAREs and Q-SNAREs, as based on the conserved arginine or glutamine residue in the centre of the SNARE motif [ 6 ]. SNAREs are localised to distinct membrane compartments of the secretory and endocytic trafficking pathways, and contribute to the specificity of intracellular membrane fusion processes.

The t-SNARE domain consists of a 4-helical bundle with a coiled-coil twist. The SNARE motif contributes to the fusion of two membranes. SNARE motifs fall into four classes: homologues of syntaxin 1a (t-SNARE), VAMP-2 (v-SNARE), and the N- and C-terminal SNARE motifs of SNAP-25.

1. The Arabidopsis genome. An abundance of soluble N-ethylmaleimide-sensitive factor adaptor protein receptors. Plant Physiol 124, 1558-69
2. SNARE complexes of different composition jointly mediate membrane fusion in Arabidopsis cytokinesis. Mol Biol Cell 24, 1593-601
3. Functions of the Plant Qbc SNARE SNAP25 in Cytokinesis and Biotic and Abiotic Stress Responses. Mol Cells 43, 313-322
4. NPSN11 is a cell plate-associated SNARE protein that interacts with the syntaxin KNOLLE. Plant Physiol 129, 530-9
5. The molecular machinery of synaptic vesicle exocytosis. Cell. Mol. Life Sci. 60, 942-60
6. Conserved structural features of the synaptic fusion complex: SNARE proteins reclassified as Q- and R-SNAREs. Proc. Natl. Acad. Sci. U.S.A. 95, 15781-6