In:
Molecular Biology of the Cell, American Society for Cell Biology (ASCB), Vol. 24, No. 18 ( 2013-09-15), p. 2876-2884
Abstract:
Reactive oxygen species (ROS) consist of potentially toxic, partly reduced oxygen species and free radicals. After H 2 O 2 treatment, yeast cells significantly increase superoxide radical production. Respiratory chain complex III and possibly cytochrome b function are essential for this increase. Disruption of complex III renders cells sensitive to H 2 O 2 but not to the superoxide radical generator menadione. Of interest, the same H 2 O 2 -sensitive mutant strains have the lowest superoxide radical levels, and strains with the highest resistance to H 2 O 2 have the highest levels of superoxide radicals. Consistent with this correlation, overexpression of superoxide dismutase increases sensitivity to H 2 O 2 , and this phenotype is partially rescued by addition of small concentrations of menadione. Small increases in levels of mitochondrially produced superoxide radicals have a protective effect during H 2 O 2 -induced stress, and in response to H 2 O 2 , the wild-type strain increases superoxide radical production to activate this defense mechanism. This provides a direct link between complex III as the main source of ROS and its role in defense against ROS. High levels of the superoxide radical are still toxic. These opposing, concentration-dependent roles of the superoxide radical comprise a form of hormesis and show one ROS having a hormetic effect on the toxicity of another.
Type of Medium:
Online Resource
ISSN:
1059-1524
,
1939-4586
DOI:
10.1091/mbc.e13-01-0052
Language:
English
Publisher:
American Society for Cell Biology (ASCB)
Publication Date:
2013
detail.hit.zdb_id:
1474922-1
SSG:
12
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