ID:ITPK1_HUMAN DESCRIPTION: RecName: Full=Inositol-tetrakisphosphate 1-kinase; EC=2.7.1.134; AltName: Full=Inositol 1,3,4-trisphosphate 5/6-kinase; Short=Inositol-triphosphate 5/6-kinase; Short=Ins(1,3,4)P(3) 5/6-kinase; EC=2.7.1.159; FUNCTION: Kinase that can phosphorylate various inositol polyphosphate such as Ins(3,4,5,6)P4 or Ins(1,3,4)P3. 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. 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. Also acts as an inositol polyphosphate phosphatase that dephosphorylate Ins(1,3,4,5)P4 and Ins(1,3,4,6)P4 to Ins(1,3,4)P3, and Ins(1,3,4,5,6)P5 to Ins(3,4,5,6)P4. May also act as an isomerase that interconverts the inositol tetrakisphosphate isomers Ins(1,3,4,5)P4 and Ins(1,3,4,6)P4 in the presence of ADP and magnesium. Probably acts as the rate-limiting enzyme of the InsP6 pathway. Modifies TNF-alpha-induced apoptosis by interfering with the activation of TNFRSF1A-associated death domain. CATALYTIC ACTIVITY: ATP + 1D-myo-inositol 3,4,5,6- tetrakisphosphate = ADP + 1D-myo-inositol 1,3,4,5,6- pentakisphosphate. CATALYTIC ACTIVITY: ATP + 1D-myo-inositol 1,3,4-trisphosphate = ADP + 1D-myo-inositol 1,3,4,5-tetrakisphosphate. CATALYTIC ACTIVITY: ATP + 1D-myo-inositol 1,3,4-trisphosphate = ADP + 1D-myo-inositol 1,3,4,6-tetrakisphosphate. COFACTOR: Binds 2 magnesium ions per subunit. BIOPHYSICOCHEMICAL PROPERTIES: Kinetic parameters: KM=0.3 uM for Ins(1,3,4)P3; KM=0.1 uM for Ins(3,4,5,6)P4; Vmax=320 pmol/min/ug enzyme with Ins(1,3,4)P3 as substrate; Vmax=780 pmol/min/ug enzyme enzyme with Ins(3,4,5,6)P4 as substrate; SUBUNIT: Monomer. Interacts with GPS1/COPS1. TISSUE SPECIFICITY: Expressed in brain > heart > skeletal muscle = kidney = pancreas = liver = placenta > lung. In brain, it is expressed in cerebellum, cerebral cortex, medulla, spinal cord, occipital lobe, frontal lobe, temporal lobe and putamen. SIMILARITY: Belongs to the ITPK1 family. SIMILARITY: Contains 1 ATP-grasp domain. CAUTION: PubMed:11533064 detected some protein kinase activity and ability to phosphorylate transcription factors c-jun/JUN and ATF2. However, PubMed:15762844 showed that it does not have protein kinase activity.
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
ModBase Predicted Comparative 3D Structure on Q13572
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
Protein Q13572 (Reactome details) participates in the following event(s):
R-HSA-994140 ITPK1 converts Ins-1,3,4-P3 to Ins-1,3,4,5-P4 R-HSA-994137 ITPK1 converts Ins-3,4,5,6-P4 to Ins-1,3,4,5,6-P5 R-HSA-2267372 ITPK1 converts Ins-1,3,4-P3 to Ins-1,3,4,6-P4 R-HSA-1855197 I(1,3,4)P3 is phosphorylated to I(1,3,4,6)P4 by ITPK1 in the cytosol R-HSA-1855172 I(1,3,4)P3 is phosphorylated to I(1,3,4,5)P4 by ITPK1 in the cytosol R-HSA-1855169 I(3,4,6)P3 is phosphorylated to I(1,3,4,6)P4 by ITPK1 in the cytosol R-HSA-1855171 I(1,3,4,6)P4 is dephosphorylated to I(1,3,4)P3 by ITPK1 in the cytosol R-HSA-1855159 I(1,3,4,6)P4 is dephosphorylated to I(3,4,6)P3 by ITPK1 in the cytosol R-HSA-1855219 I(1,3,4,5,6)P5 is dephosphorylated to I(3,4,5,6)P4 by ITPK1 in the cytosol R-HSA-1855162 I(3,4,5,6)P4 is phosphorylated to I(1,3,4,5,6)P5 by ITPK1 in the cytosol R-HSA-1855218 I(1,3,4,5)P4 is dephosphorylated to I(1,3,4)P3 by INPP5[3]/ITPK1 in the cytosol R-HSA-983231 Factors involved in megakaryocyte development and platelet production R-HSA-1855204 Synthesis of IP3 and IP4 in the cytosol R-HSA-1855167 Synthesis of pyrophosphates in the cytosol R-HSA-109582 Hemostasis R-HSA-1483249 Inositol phosphate metabolism R-HSA-1430728 Metabolism
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Common Gene Haplotype Alleles 
