Cloning and expression of a cDNA encoding human inositol 1,4,5-trisphosphate 3-kinase C
| Autor: | Valérie Pouillon, Colette Moreau, Christophe Erneux, Kazunaga Takazawa, Stephen B. Shears, Valérie Dewaste |
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| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | Biochemical Journal. 352:343-351 |
| ISSN: | 1470-8728 0264-6021 |
| DOI: | 10.1042/bj3520343 |
| Popis: | Inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)] 3-kinase catalyses the phosphorylation of Ins(1,4,5)P(3) to Ins(1,3,4,5)P(4). cDNAs encoding two isoenzymes of Ins(1,4,5)P(3) 3-kinase (3-kinases A and B) have been described previously. In the present study, we report the cloning of a full-length 2052 bp cDNA encoding a third human isoenzyme of the Ins(1,4,5)P(3) 3-kinase family, referred to as isoform C. This novel enzyme has a calculated molecular mass of 75. 207 kDa and a K(m) for Ins(1,4,5)P(3) of 6 microM. Northern-blot analysis showed the presence of a transcript of approx. 3.9 kb in various human tissues. Inositol trisphosphate 3-kinase C demonstrates enzymic activity when expressed in DH5alphaF' bacteria or COS-7 cells. Calcium alone decreases the Ins(1,4,5)P(3) 3-kinase activity of the 3-kinase C isoenzyme in transfected COS-7 cells. This inhibitory effect is reversed in the presence of calmodulin. The recombinant bacterial 3-kinase C can be adsorbed on calmodulin-Sepharose in the presence of calcium. The present data show that Ins(1,4,5)P(3) 3-kinase C: (i) shares a conserved catalytic domain of about 275 amino acids with the two other mammalian isoforms, (ii) could be purified on a calmodulin-Sepharose column and (iii) could be distinguished from the A and B isoenzymes by the effects of calcium and of calmodulin. |
| Databáze: | OpenAIRE |
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