TPC2-A1-P is a powerful and membrane permeable agonist of two pore channel 2 (TPC2) with an EC50 of 10.5 μM. TPC2-A1-P plays its role by mimicking the physiological actions of PI(3,5)P2. TPC2-A1-P also shows higher potency to induce Na2+ mobilisation from TPC2 than TPC-A1-N (HY-131614). TPC2-A1-P can be used to probe different functions of TPC2 channels in intact cells.