Munc13 C2B domain is an activity-dependent Ca2+ regulator of synaptic exocytosis

Munc13 primes synaptic vesicles for exocytosis. Studies now reveal that the central C2B domain of Munc13 contains a structurally unusual Ca2+ binding site that confers specific phospholipid-binding properties to Munc13 and is essential for regulating exocytosis upon trains of action potentials.