Acidic NAADP-releasable Ca2+ compartments in the megakaryoblastic cell line MEG01

► Two separate Ca2+ compartments in the megakaryoblastic cell line MEG01: the ER and an acidic lysosomal-like Ca2+ compartment. ► There is NAADP evoked Ca2+ release from acidic compartments and CICR in MEG01 cells. ► NAADP-induced Ca2+ release occurs through the activation of TPC1 and TPC2 in the megakaryoblastic cell line.