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Original Article |
Correspondence to: David Schubert, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd., La Jolla, CA 92037. Tel:(858) 453-4100, ext
Oxidative stress and highly specific decreases in glutathione (GSH) are associated with nerve cell death in Parkinson's disease. Using an experimental nerve cell model for oxidative stress and an expression cloning strategy, a gene involved in oxidative stressinduced programmed cell death was identified which both mediates the cell death program and regulates GSH levels. Two stress-resistant clones were isolated which contain antisense gene fragments of the translation initiation factor (eIF)2
and express a low amount of eIF2
. Sensitivity is restored when the clones are transfected with full-length eIF2
; transfection of wild-type cells with the truncated eIF2
gene confers resistance. The phosphorylation of eIF2
also results in resistance to oxidative stress. In wild-type cells, oxidative stress results in rapid GSH depletion, a large increase in peroxide levels, and an influx of Ca2+. In contrast, the resistant clones maintain high GSH levels and show no elevation in peroxides or Ca2+ when stressed, and the GSH synthetic enzyme
-glutamyl cysteine synthetase (
GCS) is elevated. The change in
GCS is regulated by a translational mechanism. Therefore, eIF2
is a critical regulatory factor in the response of nerve cells to oxidative stress and in the control of the major intracellular antioxidant, GSH, and may play a central role in the many neurodegenerative diseases associated with oxidative stress.
Key Words:
oxidative stress, glutathione, eIF2
, resistance, glutamate
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