Phosphatidylinositol 5-phosphate 4-kinase type-2 alpha (PIP4K2A) is a member of the phosphatidylinositol-4-phosphate 5-kinase family. It contains 1 PIPK domain and is expressed ubiquitously, with high levels in the brain. It catalyzes the phosphorylation of phosphatidylinositol 5-phosphate (PtdIns5P) on the fourth hydroxyl of the myo-inositol ring, to form phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). It may exert its function by regulating the levels of PtdIns5P, which functions in the cytosol by increasing AKT activity and in the nucleus signals through ING2. It may regulate the pool of cytosolic PtdIns5P in response to the activation of tyrosine phosphorylation, negatively regulate insulin-stimulated glucose uptake by lowering the levels of PtdIns5P. It also involved in thrombopoiesis, and the terminal maturation of megakaryocytes and regulation of their size.