The lipid binding proteins known as phosphatidylinositol transfer proteins (PITP) facilitate the formation of phosphatidylinositol derived second messenger molecules, which are related to the phospholipase C and phosphoinositide 3-kinase pathways. PITP are ubiquitously expressed proteins that transfer phosphatidylinositol (PI) and phosphatidylcholine (PC) between membranes enriched in PI or PC to membranes that are deficient in PI or PC. PITP mobilizes PI from the endoplasmic recticulum and regulates the release of PI from stored vesicles in the Golgi network. In mammalian cells, three smaller forms of soluble PITP are present, designated PITP(alpha), PITP(beta) and retinal degeneration B (rdgB) beta. PITP(beta) is a 271 amino acid protein that is widely expressed in various tissues. Though required for Golgi targeting, constitutive phosphorylation of Ser-262 has no effect on phospholipid transfer activity. There are two isoforms of PITP(beta) that are produced as a result of alternative splicing events.