Kinase Subfamily IP3K

Kinase Classification: Group PKL: Family IP3K

IP3K (ITPKA) is a non-protein kinase that phosphorylates inositol (1,4,5) tri-phosphate on the 3 position, to create Ins(1,3,4,5)P4.

Kinase Domain

The IPPK kinase domain is most similar to that of PIPK, which is itself a remote member of the PKL fold, and related to other inositol phosphate kinase families [1, 2].

related both to the PKL kinases as well as to the ATP-Grasp fold of ATP-driven enzymes. This was first predicted by deep sequence comparison [3] and confirmed by a crystal structure [1]. Like PIPK kinases, the N-lobe is closer to PKL while the C-lobe has similarities to the ATP-Grasp fold. The K72, D166 and D184 catalytic residues of PKLs are well conserved in IP3K [3].

Evolution

The family is found in most eukaryotes, and has three copies in human (ITPKA, ITPKB, ITPKC).

Naming

As with most inositol kinases, IP3K have several names, I3P3K, ITPK (inositol-trisphosphate 3-kinase)

References

2. Miller GJ and Hurley JH. Crystal structure of the catalytic core of inositol 1,4,5-trisphosphate 3-kinase. Mol Cell. 2004 Sep 10;15(5):703-11. DOI:10.1016/j.molcel.2004.08.005 |
3. Cheek S, Ginalski K, Zhang H, and Grishin NV. A comprehensive update of the sequence and structure classification of kinases. BMC Struct Biol. 2005 Mar 16;5:6. DOI:10.1186/1472-6807-5-6 |

Unlinked References

1. Gonzalez pmid= 15350214