Phosphatidylinositol 4-phosphate

Phosphatidylinositol 4-phosphate (PtdIns4P or PI4P) is a precursor of Phosphatidylinositol (4,5)-bisphosphate. PtdIns4P is prevalent in the membrane of the Golgi apparatus.

In the Golgi apparatus, PtdIns4P binds to the GTP-binding protein ARF and to effector proteins, including four-phosphate-adaptor protein 1 and 2 (FAPP1 and FAPP2). This three molecule complex recruits proteins that need to be carried to the cell membrane.