Unc13 proteins are required for vesicle docking and priming during exocytosis. In this issue of Neuron, Lai et al. (2017) demonstrate that Unc13 ensures that the SNAREs assemble into functional subcomplexes. In a second manuscript, Michelassi et al. (2017) identify a previously unknown autoinhibited state for Unc13 mediated by the tandem C1 and C2 domains.