Regulation of ER Ca2+ store by TSP4. A, Sample traces show the effect of TSP4 on the Ca2+ transient induced by release of ER stores by caffeine (20 mM). B, Summary data show reduced releasable Ca2+ stores, measured as Ca2+ transient amplitude, in mouse neurons incubated in TSP4. C, Summary data show TSP4 effects in rat neurons. D, Sample traces show the effect of TSP4 on the Ca2+ transient induced by the release of stores by the SERCA blocker TG, 1 μM. E, Summary data show TSP4 suppresses the TG-induced Ca2+ transient amplitude. F, Summary data show TSP4 suppresses the TG-induced elevation of resting [Ca2+] i. * p <0.05, ** p < 0.01, *** p < 0.001.