Inositol hexakisphosphate and diphosphoinositol-pentakisphosphate kinase 1 (PPIP5K1)

Bifunctional inositol kinase that acts in concert with the IP6K kinases IP6K1, IP6K2 and IP6K3 to synthesize the diphosphate group-containing inositol pyrophosphates diphosphoinositol pentakisphosphate, PP-InsP5, and bis- diphosphoinositol tetrakisphosphate, (PP)2-InsP4. PP-InsP5 and (PP)2-InsP4, also respectively called InsP7 and InsP8, regulate a variety of cellular processes, including apoptosis, vesicle trafficking, cytoskeletal dynamics, exocytosis, insulin signaling and neutrophil activation.

Phosphorylates inositol hexakisphosphate (InsP6) at positions 1 or 3 to produce PP-InsP5 that's in turn phosphorylated by IP6Ks to create (PP)2-InsP4. Instead, phosphorylates at position 1 or 3 PP-InsP5, produced by IP6Ks from InsP6, to create (PP)2-InsP4.