Catalyzes the phosphorylation of 1D-myo-inositol 1,4,5-trisphosphate (InsP3) into 1D-myo-inositol 1,3,4,5-tetrakisphosphate and participates to the regulation of calcium homeostasis (, ). Can phosphorylate inositol 2,4,5-triphosphate to inositol 2,4,5,6-tetraphosphate (By similarity).
Subcellular locations: Nucleus, Cytoplasm
Shuttles actively between nucleus and cytoplasm with both nuclear import and nuclear export activity.
Highly expressed in pancreas, skeletal muscle, liver, placenta and weakly in kidney and brain.