Cells Lacking Rieske Iron-Sulfur Protein Have a Reactive Oxygen Species-Associated Decrease in Respiratory Complexes I and IV

All bactericidal antibiotics were recently proposed to kill by inducing reactive oxygen species (ROS) production, causing destabilization of iron-sulfur (Fe-S) clusters and generating Fenton chemistry. We find that the ROS response is dispensable upon treatment with bactericidal antibiotics. Furthermore, we demonstrate that Fe-S clusters are required for killing only by aminoglycosides. In contrast to cells, using the major Fe-S cluster biosynthesis machinery, ISC, cells using the alternative machinery, SUF, cannot efficiently mature respiratory complexes I and II, resulting in impendence of the proton motive force (PMF), which is required for bactericidal aminoglycoside uptake. Similarly, during iron limitation, cells become intrinsically resistant to aminoglycosides by switching from ISC to SUF and down-regulating both respiratory complexes. We conclude that Fe-S proteins promote aminoglycoside killing by enabling their uptake.

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The essential iron-sulfur protein Rli1 is an important target accounting for inhibition of cell growth by reactive oxygen species

Molecular Biology of the Cell ◽

10.1091/mbc.e12-05-0413 ◽

2012 ◽

Vol 23 (18) ◽

pp. 3582-3590 ◽

Cited By ~ 49

Author(s):

Alawiah Alhebshi ◽

Theodora C. Sideri ◽

Sara L. Holland ◽

Simon V. Avery

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Ribosomal Subunit ◽

Reactive Oxygen ◽

Oxygen Species ◽

Sulfur Protein ◽

Iron Sulfur Protein ◽

Cellular Components

Oxidative stress mediated by reactive oxygen species (ROS) is linked to degenerative conditions in humans and damage to an array of cellular components. However, it is unclear which molecular target(s) may be the primary “Achilles’ heel” of organisms, accounting for the inhibitory action of ROS. Rli1p (ABCE1) is an essential and highly conserved protein of eukaryotes and archaea that requires notoriously ROS-labile cofactors (Fe-S clusters) for its functions in protein synthesis. In this study, we tested the hypothesis that ROS toxicity is caused by Rli1p dysfunction. In addition to being essential, Rli1p activity (in nuclear ribosomal-subunit export) was shown to be impaired by mild oxidative stress in yeast. Furthermore, prooxidant resistance was decreased by RLI1 repression and increased by RLI1 overexpression. This Rlip1 dependency was abolished during anaerobicity and accentuated in cells expressing a FeS cluster–defective Rli1p construct. The protein's FeS clusters appeared ROS labile during in vitro incubations, but less so in vivo. Instead, it was primarily55FeS-cluster supply to Rli1p that was defective in prooxidant-exposed cells. The data indicate that, owing to its essential nature but dependency on ROS-labile FeS clusters, Rli1p function is a primary target of ROS action. Such insight could help inform new approaches for combating oxidative stress–related disease.

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