Mitochondrial cysteine desulfurase iron-sulfur cluster S and aconitase are post-transcriptionally regulated by dietary iron in skeletal muscle of rats.
Cysteine desulfurase IscS is required for cellular iron-sulfur protein maturation in eukaryotes and prokaryotes. In this study, we examined the effect of dietary iron intake on the expression in rat skeletal muscle of IscS in relation to 2 iron-sulfur proteins, cytosolic aconitase (c-aconitase) and mitochondrial aconitase (m-aconitase). Three groups of male weanling Wistar rats were used; 1 group was fed an iron-deficient diet (D), and the other 2 groups were pair-fed (P) or freely fed (C) a control (35 mg Fe/kg diet) diet for 1 or 2 wk. At the end of wk 1 and 2, the mitochondrial IscS protein levels in the skeletal muscle of iron-deficient rats had decreased to 45 and 50% of those of the control and pair-fed rats, respectively, whereas the IscS mRNA levels did not differ among the 3 groups, indicating that iron deficiency affected the expression of IscS protein at the post-transcriptional level. Iron deficiency caused a 55-76% reduction in c-aconitase activity and an approximately 50% reduction in the c-aconitase protein level. The m-aconitase activity and protein level in iron-deficient rats also declined to 50 and 58-64% of the control levels, respectively. Our results indicate that dietary iron modulates mitochondrial IscS protein and aconitase at the post-transcriptional level, and mitochondrial IscS may be associated with this regulation of aconitase in skeletal muscle.
Liew
Yih-Fong
YF
Institute of Microbiology and Biochemistry, National Taiwan University, Taipei, Taiwan.
Shaw
Ning-Sing
NS
D000154:Aconitate Hydratase / Q000378:metabolism*; D000818:Animals; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D000090463:Iron Deficiencies; D019266:Iron, Dietary / Q000494:pharmacology*; D035925:Iron-Regulatory Proteins / Q000378:metabolism; D008297:Male; D008931:Mitochondria, Muscle / Q000201:enzymology*; D018482:Muscle, Skeletal / Q000201:enzymology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D019266:Iron, Dietary; D035925:Iron-Regulatory Proteins; D012333:RNA, Messenger; D000154:Aconitate Hydratase; D013437:Carbon-Sulfur Lyases; C080546:cysteine desulfurase