Inositol lipids play a major role in cell signaling by functioning as precursors of second
messengers. Of the three common inositol-containing lipids found in the plasma membrane,
phosphatidylinositol (4, 5)-bisphosphate is hydrolyzed to give diacylglycerol, which
stimulates protein kinase C, and inositol 1, 4, 5-trisphosphate, which diffuses into the cell to
release intracellular calcium. Inositol 1, 4, 5-trisphosphate is metabolized to give free inositol
by two separate pathways. Lithium inhibits the final dephosphorylation step of both …