The strong correlation between tetanus-induced RP mobilization and PTP (Kim et al., 2009; Kuromi and Kidokoro, 2003), coupled with the essential roles of Vav-Rac1 signaling and F-actin cytoskeleton networks in RP mobilization (Kuromi and Kidokoro, 2003; Park et al., 2022), implies that Epac-dependent cAMP signaling acts by promoting Rap1/Vav/Rac1-dependent actin polymerization and thus SV mobilization via actin-based molecular motors. This evidence concerns the gene RAPGEF4 and tetanus.