|
|
||||||||
CELLULAR METABOLISM
Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708-0328
Submitted 10 July 2003 ; accepted in final form 14 October 2003
Although copper is an essential metal, it is capable of catalyzing the formation of reactive oxygen species that can cause intracellular oxidative damage. We investigated the hypothesis that metal- and oxidative stress-responsive signal transduction pathways mediate the cellular and molecular responses associated with copper exposure. Transient transfection assays using COS-7 cells and mouse metallothionein-I (MT-I) or rat NAD(P)H:oxidoreductase 1-based reporter genes demonstrate that copper activates transcription via metal and antioxidant response elements. Concomitant with copper exposures is a decrease in the level of total glutathione and an increase in oxidized glutathione. Depletion of glutathione, before copper exposure, increases metal- and oxidative stress-inducible transcription and cytotoxicity. Pretreatment with the reactive oxygen scavengers aspirin or vitamin E provides partial protection against copper toxicity and reduces inducible transcription. Experiments using signal transduction inhibitors and a metal transcription factor (MTF)-1 null cell line demonstrate that copper-inducible MT-I transcription is regulated by protein kinase C and mitogen-activated protein kinase signaling pathways and requires MTF-1. The results of these studies indicate that copper activates transcription through both metal- and oxidative stress-responsive signal transduction pathways.
metallothionein; signal transduction; MAPK
This article has been cited by other articles:
![]() |
Y. Zhao, S. Gao, I.-N. Chou, P. Toselli, P. Stone, and W. Li Inhibition of the Expression of Lysyl Oxidase and Its Substrates in Cadmium-Resistant Rat Fetal Lung Fibroblasts Toxicol. Sci., April 1, 2006; 90(2): 478 - 489. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |