Metallothionein Mediates the Level and Activity of Nuclear Factor ΚB in Murine Fibroblasts
| Autor: | Wendy Kennette, Rudolfs K. Zalups, James Koropatnick, Heather L. Butcher, Olga Collins |
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| Rok vydání: | 2004 |
| Předmět: |
Mice
Knockout Pharmacology Reporter gene Expression vector Genetic Vectors NF-kappa B Transcription Factor RelA Transfection Fibroblasts Biology Molecular biology Mice IκBα Apoptosis Cell Line Tumor NIH 3T3 Cells Animals Humans Molecular Medicine Metallothionein Transcription factor Nuclear localization sequence |
| Zdroj: | Journal of Pharmacology and Experimental Therapeutics. 310:589-598 |
| ISSN: | 1521-0103 0022-3565 |
| DOI: | 10.1124/jpet.104.066126 |
| Popis: | The zinc-binding protein metallothionein (MT) is associated with resistance to apoptosis. We examined whether MT regulates the zinc-dependent antiapoptotic transcription factor nuclear factor KappaB (NF-KappaB), which is up-regulated under many conditions that lead to elevated MT expression. NF-KappaB protein levels and NF-KappaB-dependent reporter gene activity were examined in clonal MT(+) (MT-WT) and MT(-) (MT-KO) fibroblastic cell lines. The amount of cellular NF-KappaB p65 protein in MT-KO was less than 20% of the amount in MT-WT cells, in accord with increased sensitivity of MT-KO cells to apoptosis. NF-KappaB p65 mRNA levels, and NF-KappaB p50 subunit and IKappaBalpha protein levels, were unchanged. NF-KappaB activity assessed by expression of a transfected NF-KappaB reporter construct was less than half that observed in MT-KO cells. Decreased nuclear localization of NF-KappaB p65 in MT-KO clones was not responsible for differences in activity. In fact, MT-KO cells had higher nuclear levels of NF-KappaB p65 than did MT-WT cells, despite a lower cellular NF-KappaB level and function, suggesting that metallothionein mediated the specific activity of NF-KappaB. Reconstitution of MT by stable incorporation of an MT-1 expression vector in MT-KO cells resulted in increased NF-KappaB p65 (but not IKappaBalpha or NF-KappaB p50), increased NF-KappaB-dependent reporter activity, and increased resistance to apoptosis. These data support the hypothesis that metallothionein positively regulates the cellular level and activity of NF-KappaB. |
| Databáze: | OpenAIRE |
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