PPIP5K2 (diphosphoinositol pentakisphosphate kinase 2) is a bifunctional inositol kinase that synthesizes inositol pyrophosphates (PP-InsPs), including PP-InsP5 (InsP7) and (PP)2-InsP4 (InsP8), working in concert with IP6K kinases 1234. The enzyme phosphorylates inositol hexakisphosphate (InsP6) at position 1 to produce PP-InsP5, which is further phosphorylated by IP6Ks to generate (PP)2-InsP4 12. PPIP5K2 possesses both kinase and phosphatase activities, with kinetic properties insulated from cellular bioenergetic stress 5. These PP-InsP products regulate diverse cellular processes including apoptosis, vesicle trafficking, cytoskeletal dynamics, exocytosis, insulin signaling, and neutrophil activation 1234. PPIP5K2 is essential for normal hearing; mutations cause autosomal recessive sensorineural hearing loss (DFNB100), with the gene expressed in cochlear and vestibular hair cells 4. Beyond auditory function, PPIP5K2 promotes tumorigenesis in multiple cancers: it facilitates colorectal cancer through DNA homologous recombination repair 6 and non-small cell lung cancer via AKT/mTOR signaling 7. Machine learning studies nominate PPIP5K2 within the inositol phosphate biosynthetic pathway as potentially involved in Parkinson's disease 8, while variants have been identified in keratoconus 9.