Inositol-tetrakisphosphate 1-kinase 1

UniProtKB accession:  Q84Y01

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UniProtKB description:  Kinase that can phosphorylate various inositol polyphosphate such as Ins(3,4,5,6)P4 or Ins(1,3,4)P3 and participates in phytic acid biosynthesis in developing seeds (PubMed:12586875, PubMed:32123645). Phosphorylates Ins(3,4,5,6)P4 at position 1 to form Ins(1,3,4,5,6)P5. This reaction is thought to have regulatory importance, since Ins(3,4,5,6)P4 is an inhibitor of plasma membrane Ca(2+)-activated Cl(-) channels, while Ins(1,3,4,5,6)P5 is not (PubMed:12586875). Also phosphorylates Ins(1,3,4)P3 on O-5 and O-6 to form Ins(1,3,4,6)P4, an essential molecule in the hexakisphosphate (InsP6) pathway (PubMed:12586875). Also able to phosphorylate Ins(3,5,6)P3 but not Ins(1,4,5)P3, Ins(2,4,5)P3, Ins(1,3,4,6)P4 nor Ins(1,3,5,6)P4. Has higher specific activity on Ins(3,4,5,6)P4 than Ins(1,3,4)P3 and Ins(3,5,6)P3 (PubMed:12586875). Can also could use Ins(1,2,5,6)P4 as a substrate (PubMed:12586875). Able to add a beta-phosphate to the 3 positions of Ins(1,2,3,4,5)P5 and to add beta-phosphate to InsP6 to yield 5-InsP7, thus exhibiting InsP6 kinase activity (PubMed:35635723). Has also Ins(1,3,4,5,6)P5 phosphatase activity (PubMed:35635723).