Intracellular membrane fusion: SNAREs only?

The past two years have seen vigorous attempts to elucidate the mechanism driving intracellular membrane fusion, Much attention was focused on the role of SNARE complexes. Their crystal structure was solved and fusion was reconstituted using proteoliposomes with purified SNAREs suggesting them to be the minimal machinery for fusion. Work on physiological membranes, however, points in another direction and has spurred a hot debate on the function of SNAREs.