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Many essential proteins in the cells of higher organisms are ferried from one organelle to the next inside small membrane packages. When they arrive at their target, these vesicles merge with the membrane they find there, an event called fusion. Growth, secretion and other vital processes all depend on this complex phenomenon. Recently cellular proteins have been identified that seem to control fusion mechanisms in all eukaryotic cells, from yeast to humans.
Certain cytoplasmic proteins, called NSF proteins (N-ethyl-maleimide-sensitive fusion proteins) and SNAPs (soluble NSF attachment proteins), are essential for membrane fusion inside mammalian cells. According to the researchers, the high specificity in the fusion machinery is due to membrane proteins, called SNAREs (this means both SNAP receptor and trap). The four SNARE proteins had previously been identified as components of the synapses between neurons.
[Scientific American, June 1993, 11, and, in more detail, Nature 362 (1993), 318-324, 353-355, 297-298.]