FunctionPhosphorylates phosphatidylinositol (PI) in the first committed step in the production of the second messenger inositol-1,4,5,-trisphosphate (PIP). May regulate Golgi disintegration/reorganization during mitosis, possibly via its phosphorylation. Involved in Golgi-to-plasma membrane trafficking.
Tissue specificityWidely expressed with highest levels in heart, skeletal muscle, pancreas, testis and ovary. Weakly expressed in liver.
Sequence similaritiesBelongs to the PI3/PI4-kinase family. Type III PI4K subfamily. Contains 1 PI3K/PI4K domain. Contains 1 PIK helical domain.
Cellular localizationEndomembrane system. Mitochondrion outer membrane. Rough endoplasmic reticulum membrane. Golgi apparatus. Cytoplasm, perinuclear region. Found in the outer membrane of mitochondria and membranes of the rough endoplasmic reticulum. Recruited to the Golgi complex by the small GTPase ARF to stimulate the synthesis of phosphatidylinositol 4,5-bisphosphate (PIP2) on the Golgi complex.