Phosphatidylinositol 4,5-biphosphate (PIP2) is a membrane phospholipid that has been implicated in a variety of cellular processes, including synaptic vesicle recycling and signal transduction pathways. PLCD4 hydrolyzes PIP2 to generate 2 second messenger molecules diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3).