A secondary messenger that induces calcium mobilization; induces calcium release from endosomes and lysosomes via TPC2 and TPC1; induces calcium mobilization in sea urchin and starfish eggs post fertilization to block polyspermy and activate embryogenesis; induces VEGF-mediated angiogenesis in HUVECs; alkalizes lysosomal pH, arresting autophagic flux in mouse embryonic stem cells