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MGP004620

UniProt Annotations

Entry Information
Gene Namediphosphoinositol pentakisphosphate kinase 2
Protein EntryVIP2_HUMAN
UniProt IDO43314
SpeciesHuman
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative splicing; Named isoforms=2; Name=1; IsoId=O43314-1; Sequence=Displayed; Name=2; IsoId=O43314-2; Sequence=VSP_030636; Note=No experimental confirmation available.;
Biophysicochemical PropertiesKinetic parameters: KM=0.13 uM for InsP6 {ECO:0000269|PubMed:17690096}; KM=0.19 uM for InsP7 {ECO:0000269|PubMed:17690096}; Vmax=0.39 nmol/min/mg enzyme with InsP6 as substrate {ECO:0000269|PubMed:17690096}; Vmax=1.38 nmol/min/mg enzyme with InsP7 as substrate {ECO:0000269|PubMed:17690096};
Catalytic ActivityATP + 1D-myo-inositol 1-diphosphate 2,3,4,5,6- pentakisphosphate = ADP + 1D-myo-inositol 1,5-bis(diphosphate) 2,3,4,6-tetrakisphosphate.
Catalytic ActivityATP + 1D-myo-inositol 5-diphosphate 1,2,3,4,6- pentakisphosphate = ADP + 1D-myo-inositol 1,5-bis(diphosphate) 2,3,4,6-tetrakisphosphate.
Catalytic ActivityATP + 1D-myo-inositol hexakisphosphate = ADP + 1D-myo-inositol 1-diphosphate 2,3,4,5,6-pentakisphosphate.
Catalytic ActivityATP + 1D-myo-inositol hexakisphosphate = ADP + 1D-myo-inositol 5-diphosphate 1,2,3,4,6-pentakisphosphate.
DomainThe polyphosphoinositide-binding domain mediates binding of PtdIns(3,4,5)P3 and InsP6. Despite its similarity with the phosphatase domain of histidine acid phosphatases, it has no phosphatase activity.
FunctionBifunctional inositol kinase that acts in concert with the IP6K kinases IP6K1, IP6K2 and IP6K3 to synthesize the diphosphate group-containing inositol pyrophosphates diphosphoinositol pentakisphosphate, PP-InsP5, and bis- diphosphoinositol tetrakisphosphate, (PP)2-InsP4. PP-InsP5 and (PP)2-InsP4, also respectively called InsP7 and InsP8, regulate a variety of cellular processes, including apoptosis, vesicle trafficking, cytoskeletal dynamics, exocytosis, insulin signaling and neutrophil activation. Phosphorylates inositol hexakisphosphate (InsP6) at positions 1 or 3 to produce PP-InsP5 which is in turn phosphorylated by IP6Ks to produce (PP)2-InsP4. Alternatively, phosphorylates at position 1 or 3 PP-InsP5, produced by IP6Ks from InsP6, to produce (PP)2-InsP4. {ECO:0000269|PubMed:17690096, ECO:0000269|PubMed:17702752}.
Sequence CautionSequence=BAA24863.2; Type=Erroneous initiation; Evidence={ECO:0000305}; Sequence=EAW49076.1; Type=Erroneous gene model prediction; Evidence={ECO:0000305};
SimilarityBelongs to the histidine acid phosphatase family. VIP1 subfamily. {ECO:0000305}.
Subcellular LocationCytoplasm, cytosol {ECO:0000269|PubMed:17690096}.
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