Both transport within the cell and secretion to the outside depend on small membrane bubbles called vesicles that can form from existing membranes. When vesicles arrive at their destination, they fuse into the target membrane. How vesicles merging in and out of membranes can achieve high specificity and the high speed required to keep, for example, our brains in working order, was a complete mystery until 1993. In that year, the group of James Rothman at the Memorial Sloan-Kettering Cancer Center, New York, discovered a group of proteins called Snares. Recent results from the same laboratory now explain in detail how these proteins control and drive membrane fusion.
Snare is short for SNAP receptors.
SNAP stands for Soluble NSF Attachment Proteins. But just remember that Snares are proteins attached to membranes, which tend to 'ensnare' vesicles. When they reported the discovery of Snares in 1993, Rothman's group put forward what is now known as the 'Snare hypothesis', proposing that Snares control the specificity of membrane fusion. Although this topic has generated a lot of research and interest among cell biologists, it is only in recent years that firm evidence for this hypothesis has been found. In 1999, Rothman's group demonstrated that recombination of test vesicles in vitro actually leads to the contents of the vesicles being mixed.