Fast Vesicle Fusion in Living Cells Requires at Least Three SNARE Complexes

Abstract

Three's the Charm The molecular machinery mediating membrane fusion during secretion from a cell requires a complex of so-called SNARE protein that forms a coiled bundle of four parallel α-helices. Mohrmann et al. (p. 502 , published online 16 September) developed an elegant approach to find out how many SNARE complexes are required to promote secretion of individual secretory vesicles in living chromaffin cells by titrating the ratio of wild-type and mutant SNARE proteins expressed. For fast synchronous release, a minimum of three SNARE complexes per vesicle were required. Fewer SNARE complexes resulted in slower release.