Phosphatidylinositol-4-Kinase Type 2 Alpha (PI4K2a)

Phosphatidylinositolpolyphosphates (PtdInsPs) are centrally involved in many biologic processes, ranging from cell growth and organization of the actin cytoskeleton to endo- and exocytosis. PI4KII phosphorylates PtdIns at the D-4 position, an essential step in the biosynthesis of PtdInsPs . By peptide sequencing, database analysis, and RT-PCR of A431 total RNA, they obtained a full-length PI4KII cDNA. The deduced 479-amino acid protein has a calculated molecular mass of about 54 kD. PI4KII has a kinase domain and a leucine zipper, but no transmembrane sequence or acylation motif. Northern blot analysis detected a 6.6-kb transcript in all tissues examined. Expression was highest in kidney, brain, heart, skeletal muscle, and placenta, and was lowest in colon, thymus, and small intestine.