The SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein (SNAP) receptor) family are a large group of proteins that mediate vesicle-fusion steps in the endocytic and secretory pathways. SNAREs are cytoplasmic, membrane-anchored proteins that contain a 60 amino acid SNARE domain that interacts with other SNARE domains: three form the target membrane and one form the vesicle membrane, to form a four-helix bundle that pulls the two membranes in close proximity and promotes fusion. After fusion, the complexes are dissembled by NSF (N-ethylmaleimide-sensitive factor) and SNAPs (Soluble NSF Attachment Proteins). (Adapted from PMID:15893389 and FBrf0216182).