(A) DISC1 can bind and phosphorylate GSK3β to tonically inhibit its activity, whereas truncated (tr) DISC1 is unable to phosphorylate GSK3β, releasing it from inhibition. (B,C) SV proteins interact with terminal membrane proteins to form SNARE complexes (see E) that dock vesicles to release sites. Upon Ca²⁺ influx through VGCCs (C), docked vesicles fuse with the plasma membrane to release neurotransmitter (D). (E) trDISC1 releases GSK3β from inhibition allowing it to phosphorylate (maroon spheres) VGCCs leading to their dissociation from the secretion machinery. Once uncoupled, VGCCs are ubiquitinated and degraded by the proteosome.