Three SNARE proteins are known to be in a complex involved in vacuole–vacuole fusion. Ungermann et al. identify two additional SNAREs in this complex, suggesting that SNARE complexes can be larger and more complicated than previously thought (page ).
Other researchers have determined the crystal structure of a complex of purified neuronal SNARE proteins implicated in synaptic exocytosis. The structure is built around a core of four parallel coiled-coil domains contributed by three proteins. The established complex of vacuolar SNARE proteins was consistent with this model (although it seemed that each protein only contributed a single coiled-coil), but Ungermann et al. use immunoaffinity purification and mass spectrometry to add two more SNAREs, Vti1p and Ykt6p, bringing the total to five. The authors use immunoprecipitation to confirm that the proteins define a single complex, and antibodies and mutants to show that both of the new proteins are required for fusion....
