Cellular Redox Systems Impact the Aggregation of Cu,Zn Superoxide Dismutase Linked to Familial Amyotrophic Lateral Sclerosis.
Protein misfolding is implicated in neurodegenerative diseases such as ALS, where mutations of superoxide dismutase 1 (SOD1) account for about 20% of the inherited mutations. Human SOD1 (hSOD1) contains four cysteines, including Cys(57) and Cys(146), which have been linked to protein stability and folding via forming a disulfide bond, and Cys(6) and Cys(111) as free thiols. But the roles of the cellular oxidation-reduction (redox) environment in SOD1 folding and aggregation are not well understood. Here we explore the effects of cellular redox systems on the aggregation of hSOD1 proteins. We found that the known hSOD1 mutations G93A and A4V increased the capability of the thioredoxin and glutaredoxin systems to reduce hSOD1 compared with wild-type hSOD1. Treatment with inhibitors of these redox systems resulted in an increase of hSOD1 aggregates in the cytoplasm of cells transfected with mutants but not in cells transfected with wild-type hSOD1 or those containing a secondary C111G mutation. This aggregation may be coupled to changes in the redox state of the G93A and A4V mutants upon mild oxidative stress. These results strongly suggest that the thioredoxin and glutaredoxin systems are the key regulators for hSOD1 aggregation and may play critical roles in the pathogenesis of ALS.
From the Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177, Stockholm, Sweden, the Department of Pathology and Experimental Therapeutics, Faculty of Medicine, Campus Bellvitge, University of Barcelona, Feixa Llarga s/n. Hospitalet de Llobregat, 08907 Barcelona, Spain, and the Bellvitge Biomedical Research Institute, Gran Via de l'Hospitalet, 199-203, L'Hospitalet de Llobregat, Barcelona, 08908 Barcelona, Spain.
Cristina
C
Álvarez-Zaldiernas
From the Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177, Stockholm, Sweden, junlu@swu.edu.cn.
Jun
J
Lu
From the Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177, Stockholm, Sweden.
Yujuan
Y
Zheng
From the Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177, Stockholm, Sweden.
Hongqian
H
Yang
the Department of Pathology and Experimental Therapeutics, Faculty of Medicine, Campus Bellvitge, University of Barcelona, Feixa Llarga s/n. Hospitalet de Llobregat, 08907 Barcelona, Spain, and the Bellvitge Biomedical Research Institute, Gran Via de l'Hospitalet, 199-203, L'Hospitalet de Llobregat, Barcelona, 08908 Barcelona, Spain.
Juan
J
Blasi
the Department of Pathology and Experimental Therapeutics, Faculty of Medicine, Campus Bellvitge, University of Barcelona, Feixa Llarga s/n. Hospitalet de Llobregat, 08907 Barcelona, Spain, and the Bellvitge Biomedical Research Institute, Gran Via de l'Hospitalet, 199-203, L'Hospitalet de Llobregat, Barcelona, 08908 Barcelona, Spain solsona@ub.edu.
Carles
C
Solsona
From the Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177, Stockholm, Sweden, arne.holmgren@ki.se.
Arne
A
Holmgren
D019943:Amino Acid Substitution; D000690:Amyotrophic Lateral Sclerosis / Q000201:enzymology / Q000235:genetics; D000818:Animals; D045744:Cell Line, Tumor; D054477:Glutaredoxins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D020125:Mutation, Missense; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D066263:Protein Aggregation, Pathological / Q000201:enzymology / Q000235:genetics; D017510:Protein Folding; D051381:Rats; D000072105:Superoxide Dismutase-1 / Q000235:genetics / Q000378:metabolism; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism
D054477:Glutaredoxins; C000606290:SOD1 protein, human; D013879:Thioredoxins; C000606292:Sod1 protein, rat; D000072105:Superoxide Dismutase-1
ALS (Lou Gehrig disease); SOD1; cysteine 111; glutaredoxin; glutathione; oxidative stress; protein aggregation; reduction-oxidation (redox); thiol; thioredoxin