Glycerophosphoinositol 5-phosphate (GroPI(5)P) is a synthetic, purified PI(5)P without acyl chains at the 1- and 2-positions of the glycerol. Phosphoinositides (PIPns) are minor components of cellular membranes but are integral signaling molecules for cellular communication. Phosphatidylinositol 5-phosphate (PI(5)P) is a rare lipid found in the nucleus that can bind the PHD finger of the nuclear adapter protein ING2. PI(5)P is phosphorylated to PI(4,5)P2 by Type II PIP kinases.