Inositol phosphates are important signaling molecules involved in numerous cellular functions. Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), aka IP3, is a second messenger produced by phospholipase C catalyzed hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2). IP3 binds to the IP3-receptor on the endoplasmic reticulum causing calcium to be released through the opening of a tetrameric ion channel. IP3 is rapidly metabolized by a specific series of inositol phosphatases and kinases.
