Hydrolyzes the phosphatidylinositol 4,5-bisphosphate (PIP2) to generate 2 second messenger molecules diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3). DAG mediates the activation of protein kinase C (PKC), while IP3 releases Ca(2+) from intracellular stores (By similarity). a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-4,5-bisphosphate) + H2O = 1D-myo-inositol 1,4,5-trisphosphate + a 1,2-diacyl-sn-glycerol + H(+) Binds 5 Ca(2+) ions per subunit. Two of the Ca(2+) ions are bound to the C2 domain. Localizes at the cleavage furrow during cytokinesis. The C2 domain is a Ca(2+)-dependent membrane-targeting module. The PH domain mediates interaction with the surface membrane by binding to PIP2.