Aconitase (Aco1p) is a multifunctional protein: It is an enzyme of the tricarboxylic acid cycle. In animal cells, Aco1p also is a cytosolic protein binding to mRNAs to regulate iron metabolism. In yeast, Aco1p was identified as a component of mtDNA nucleoids. Here we show that yeast Aco1p protects mtDNA from excessive accumulation of point mutations and ssDNA breaks and suppresses reductive recombination of mtDNA. Aconitase binds to both ds- and ssDNA, with a preference for GC-containing sequences. Therefore, mitochondria are opportunistic organelles that seize proteins, such as metabolic enzymes, for construction of the nucleoid, an mtDNA maintenance/segregation apparatus.
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http://dx.doi.org/10.1073/pnas.0703078104 | DOI Listing |
Two aconitase isoforms are present in mammalian cells: the mitochondrial aconitase (ACO2) that catalyzes the reversible isomerization of citrate to isocitrate in the citric acid cycle, and the bifunctional cytosolic enzyme (ACO1), which also plays a role as an RNA-binding protein in the regulation of intracellular iron metabolism. Aconitase activities in the different subcellular compartments can be selectively inactivated by different genetic defects, iron depletion, and oxidative or nitrative stress. Aconitase contains a [4Fe-4S] cluster that is essential for substrate coordination and catalysis.
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Cyclica Inc., 207 Queens Quay W Suite 420, Toronto, ON, M5J 1A7, Canada.
Despite the vital role of iron and vulnerability of iron metabolism in disease states, it remains largely unknown whether chemicals interacting with cellular proteins are responsible for perturbation of iron metabolism. We previously demonstrated that cisplatin was an inhibitor of the iron regulatory system by blocking IRP2 (iron regulatory protein 2) binding to an iron-responsive element (IRE) located in the 3'- or 5'-UTR (untranslated region) of key iron metabolism genes such as transferrin receptor 1 (TfR1) and ferritin mRNAs. To guide the development of new chemical probes to modulate the IRP-IRE regulatory system, we used an artificial intelligence (AI)-based ligand design and screened a chemical library composed of cysteine-reactive warheads.
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Henan Provincial People's Hospital, People's Hospital of Henan University, People's Hospital of Zhengzhou University, Zhengzhou, China.
Background And Purpose: Infantile cerebellar retinal degeneration (ICRD) (OMIM #614559) is a rare autosomal recessive inherited disease associated with mutations in the aconitase 2 (ACO2) gene. We report a Chinese girl with novel compound heterozygous variants in , who presented at 7 months of age with psychomotor retardation, truncal hypotonia, and ophthalmologic abnormalities. This study aims to investigate the potential molecular mechanisms underlying deficiency-induced neuropathy.
View Article and Find Full Text PDFOrphanet J Rare Dis
November 2024
Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, Medical Genetics Institute of Henan Province, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, 450000, China.
Background: Cellular iron metabolism is essential for maintaining various biological processes in organisms, and this is influenced by the function of iron-responsive element-binding protein 2 (IRP2), encoded by the IREB2 gene. Since 2019, three cases of a genetic neurodegenerative syndrome resulting from compound heterozygous mutations in IREB2 have been documented, highlighting the crucial role of IRP2 in regulating iron metabolism homeostasis. This study aims to investigate the molecular basis in a single proband born to non-consanguineous healthy parents, presenting with severe psychomotor developmental abnormalities and microcytic anemia.
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