New insight in expression, transport, and secretion of brain-derived neurotrophic factor: Implications in brain-related diseases

Figure 2 Schematic illustration of activity-dependent brain-derived neurotrophic factor secretion. A possible mechanism of intracellular Ca²⁺-dependent secretion of BDNF suggested in literature. Ca²⁺ influx through NMDA receptor/L-type VGCC and subsequent Ca²⁺ release of internal stores via ryanodine receptors are required for secretion. CaMKII, PKA, synaptotagmin IV, and CAPS2 also critically contribute to the membrane fusion process of BDNF-containing vesicles. VGCC: L-type voltage-gated calcium channels; CaMKII: calcium/calmodulin-dependent protein kinase II; PKA: protein kinase A; CAPS2: Ca²⁺-dependent activator protein for secretion 2; BDNF: Brain-derived neurotrophic factor.