Loading...
SOD1 mutations disrupt redox-sensitive Rac regulation of NADPH oxidase in a familial ALS model
Harraz, Maged M. Marden, Jennifer J. Zhou, Weihong Zhang, Yulong Williams, Aislinn Schöneich, Christian Engelhardt, John F.
Harraz, Maged M.
Marden, Jennifer J.
Zhou, Weihong
Zhang, Yulong
Williams, Aislinn
Schöneich, Christian
Engelhardt, John F.
Citations
Altmetric:
Abstract
Neurodegeneration in familial amyotrophic lateral sclerosis (ALS) is associated with enhanced redox stress caused by dominant mutations in superoxide dismutase–1 (SOD1). SOD1 is a cytosolic enzyme that facilitates the conversion of superoxide (O2•–) to H2O2. Here we demonstrate that SOD1 is not just a catabolic enzyme, but can also directly regulate NADPH oxidase–dependent (Nox-dependent) O2•– production by binding Rac1 and inhibiting its GTPase activity. Oxidation of Rac1 by H2O2 uncoupled SOD1 binding in a reversible fashion, producing a self-regulating redox sensor for Nox-derived O2•– production. This process of redox-sensitive uncoupling of SOD1 from Rac1 was defective in SOD1 ALS mutants, leading to enhanced Rac1/Nox activation in transgenic mouse tissues and cell lines expressing ALS SOD1 mutants. Glial cell toxicity associated with expression of SOD1 mutants in culture was significantly attenuated by treatment with the Nox inhibitor apocynin. Treatment of ALS mice with apocynin also significantly increased their average life span. This redox sensor mechanism may explain the gain-of-function seen with certain SOD1 mutations associated with ALS and defines new therapeutic targets.
Description
This is the publisher's version, also available electronically from http://www.jci.org/articles/view/34060
Date
2008-02-01
Journal Title
Journal ISSN
Volume Title
Publisher
American Society for Clinical Investigation
Collections
Research Projects
Organizational Units
Journal Issue
Keywords
Citation
Harraz, Maged M. et al. (2008). SOD1 mutations disrupt redox-sensitive Rac regulation of NADPH oxidase in a familial ALS model. Journal of Clinical Investigation 118(2):659-670. http://www.dx.doi.org/10.1172/JCI34060