Securing SNAREs for assembly.

SNARE proteins are essential for exocytosis, mediating the fusion of vesicles with their target membrane. Tethering factors play a key role in chaperoning SNARE assembly; however, the underlying molecular mechanisms are not well-understood. Here, Travis et al. report two crystal structures of a yeast tethering factor, the Dsl1 complex, bound with two SNARE proteins, revealing new insights into how tethering factors bridge vesicles to target membranes, recruit multiple SNARE proteins, trigger their conformational changes, and facilitate SNARE assembly.