Phosphatidylinositol-4-Phosphate-5-Kinase Type I Alpha (PIP5K1a)

Phosphatidylinositol-4-phosphate 5-kinases synthesize phosphatidylinositol 4,5-bisphosphate by phosphorylating phosphatidylinositol 4-phosphate.The deduced 549-amino acid protein has the conserved kinase homology domain of PIP5K family members. Within this domain, PIP5K1A shows 83% and 35% amino acid identity with PIP5K1B and PIP5K2A , respectively. Overall, the PIP5K1A and PIP5K1B proteins are 64% identical. Recombinant PIP5K1A expressed in bacteria had a molecular mass of approximately 66.3 kD. The authors isolated additional PIP5K1A cDNAs which they suggested represent splicing isoforms. Northern blot analysis detected a major 4.2-kb PIP5K1A transcript which had a wide tissue distribution.