Phosphatidylinositol transfer protein alpha （PITPNA） is found in the cytoplasm， where it catalyzes the transfer of phosphatidylinositol （PI） and phosphatidylcholine （PC） between membranes. PITPNA belongs to a family of lipid-binding proteins which transfer molecules of phosphatidylinositol or phosphatidylcholine between membrane surfaces. PITPNA is implicated in phospholipase C signaling and in the production of phosphatidylinositol 3， 4， 5-trisphosphate （PIP3） by phosphoinositide-3-kinase.
