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Cell Signal. 1995 Sep;7(7):643-50.

Molecular study and regulation of D-myo-inositol 1,4,5-trisphosphate 3-kinase.

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Institut de Recherche Interdisciplinaire en Biologie Humaine et Nucléaire (IRIBHN), Université Libre de Bruxelles, Belgium.


D-myo-Inositol 1,4,5-trisphosphate (InsP3) is a critical second messenger involved in signal transduction, i.e., calcium homeostasis. InsP3-kinase directly regulates the levels of InsP3 and D-myo-inositol 1,3,4,5-tetrakisphosphate (InsP4). InsP3 3-kinase is a calmodulin (CaM)-dependent enzyme and is also a target for phosphorylation by protein kinase C (PKC). Molecular cloning of cDNA's encoding proteins presenting InsP3 3-kinase activity establish the existence of distinct isoenzymes (at least three: A, B and C). These isoforms are differentially expressed and regulated by calcium/CaM. Site-directed mutagenesis and chemical modification of InsP3 3-kinase A led to the identification of three charged residues involved in ATP/Mg2+ binding among the catalytic domain and a hydrophobic residue taking part of the CaM binding site.

[Indexed for MEDLINE]

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