May play a role in endocytic and/or exocytic pathways. a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol) + ATP = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol 4-phosphate) + ADP + H(+) Interacts with LAS17. Located at both the plasma and vacuolar membrane. Present with 56 molecules/cell in log phase SD medium. Belongs to the PI3/PI4-kinase family.