Inositol-1,4,5-Trisphosphate-3-Kinase C (ITPKC)

ITPKC encodes a member of the inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)] 3-kinase family of enzymes that catalyze the phosphorylation of inositol 1,4,5-trisphosphate to 1,3,4,5-tetrakisphosphate. The encoded protein is localized to the nucleus and cytoplasm and has both nuclear import and nuclear export activity. Single nucleotide polymorphisms in this gene are associated with Kawasaki disease.Sequence analysis predicted that the 683-amino acid protein contains an Ins(1,4,5)P3-binding site with a lys262 residue that is conserved in ITPKA and ITPKB, a conserved ATP-binding site, and 6 potential protein kinase C phosphorylation sites. In contrast to ITPKA and ITPKB, ITPKC has no calmodulin kinase II phosphorylation site. Functional analysis indicated that ITPKC is relatively weakly activated by the calcium-calmodulin complex.