May act as a scaffold to localize and regulate type I phosphatidylinositol 4-phosphate 5-kinases to specific compartments within the cell, where they generate PI(4,5)P2 for actin nucleation, signaling and scaffold protein recruitment and conversion to PI(3,4,5)P3. Interacts with type I phosphatidylinositol 4-phosphate 5-kinases, including PIP5K1A AND PIP5K1B. Localized to large cytoplasmic vesicular structures. Highly expressed in brain and testis, relatively to heart, spleen, lung, liver, skeletal muscle and kidney. In spite of its similarity to other phosphatidylinositol kinases, lacks intrinsic lipid kinase activity.