Biomaterial Database

The function of glutaredoxin GRXS15 is required for lipoyl-dependent dehydrogenases in mitochondria. 2021

Anna Moseler, and Inga Kruse, and Andrew E Maclean, and Luca Pedroletti, and Marina Franceschetti, and Stephan Wagner, and Regina Wehler, and Katrin Fischer-Schrader, and Gernot Poschet, and Markus Wirtz, and Peter Dörmann, and Tatjana M Hildebrandt, and Rüdiger Hell, and Markus Schwarzländer, and Janneke Balk, and Andreas J Meyer

Institute of Crop Science and Resource Conservation (INRES)-Chemical Signalling, University of Bonn, 53113 Bonn, Germany.

Iron-sulfur (Fe-S) clusters are ubiquitous cofactors in all life and are used in a wide array of diverse biological processes, including electron transfer chains and several metabolic pathways. Biosynthesis machineries for Fe-S clusters exist in plastids, the cytosol, and mitochondria. A single monothiol glutaredoxin (GRX) is involved in Fe-S cluster assembly in mitochondria of yeast and mammals. In plants, the role of the mitochondrial homolog GRXS15 has only partially been characterized. Arabidopsis (Arabidopsis thaliana) grxs15 null mutants are not viable, but mutants complemented with the variant GRXS15 K83A develop with a dwarf phenotype similar to the knockdown line GRXS15amiR. In an in-depth metabolic analysis of the variant and knockdown GRXS15 lines, we show that most Fe-S cluster-dependent processes are not affected, including biotin biosynthesis, molybdenum cofactor biosynthesis, the electron transport chain, and aconitase in the tricarboxylic acid (TCA) cycle. Instead, we observed an increase in most TCA cycle intermediates and amino acids, especially pyruvate, glycine, and branched-chain amino acids (BCAAs). Additionally, we found an accumulation of branched-chain α-keto acids (BCKAs), the first degradation products resulting from transamination of BCAAs. In wild-type plants, pyruvate, glycine, and BCKAs are all metabolized through decarboxylation by mitochondrial lipoyl cofactor (LC)-dependent dehydrogenase complexes. These enzyme complexes are very abundant, comprising a major sink for LC. Because biosynthesis of LC depends on continuous Fe-S cluster supply to lipoyl synthase, this could explain why LC-dependent processes are most sensitive to restricted Fe-S supply in grxs15 mutants.

UI	MeSH Term	Description	Entries
D007506	Iron-Sulfur Proteins	A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.	Iron-Sulfur Protein,Iron Sulfur Proteins,Iron Sulfur Protein,Protein, Iron-Sulfur,Proteins, Iron Sulfur,Proteins, Iron-Sulfur,Sulfur Proteins, Iron
D008058	Dihydrolipoamide Dehydrogenase	A flavoprotein containing oxidoreductase that catalyzes the reduction of lipoamide by NADH to yield dihydrolipoamide and NAD+. The enzyme is a component of several MULTIENZYME COMPLEXES.	Lipoamide Dehydrogenase,NAD Diaphorase,NADH Diaphorase,Diaphorase (Lipoamide Dehydrogenase),Dihydrolipoyl Dehydrogenase,Glycine Decarboxylase Complex L-Protein,L-Protein, Glycine Decarboxylase Complex,Lipoamide Dehydrogenase, Valine,Lipoic Acid Dehydrogenase,Lipoyl Dehydrogenase,Valine Lipoamide Dehydrogenase,Dehydrogenase, Dihydrolipoamide,Dehydrogenase, Dihydrolipoyl,Dehydrogenase, Lipoamide,Dehydrogenase, Lipoic Acid,Dehydrogenase, Lipoyl,Dehydrogenase, Valine Lipoamide,Diaphorase, NAD,Diaphorase, NADH,Glycine Decarboxylase Complex L Protein
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D005838	Genotype	The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.	Genogroup,Genogroups,Genotypes
D014644	Genetic Variation	Genotypic differences observed among individuals in a population.	Genetic Diversity,Variation, Genetic,Diversity, Genetic,Diversities, Genetic,Genetic Diversities,Genetic Variations,Variations, Genetic
D017343	Genes, Plant	The functional hereditary units of PLANTS.	Plant Genes,Gene, Plant,Plant Gene
D017360	Arabidopsis	A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.	Arabidopsis thaliana,Cress, Mouse-ear,A. thaliana,A. thalianas,Arabidopses,Arabidopsis thalianas,Cress, Mouse ear,Cresses, Mouse-ear,Mouse-ear Cress,Mouse-ear Cresses,thaliana, A.,thaliana, Arabidopsis,thalianas, A.
D054477	Glutaredoxins	A family of thioltransferases that contain two active site CYSTEINE residues, which either form a disulfide (oxidized form) or a dithiol (reduced form). They function as an electron carrier in the GLUTHIONE-dependent synthesis of deoxyribonucleotides by RIBONUCLEOTIDE REDUCTASES and may play a role in the deglutathionylation of protein thiols. The oxidized forms of glutaredoxins are directly reduced by the GLUTATHIONE.	Glutaredoxin,Glutaredoxin 1,Glutaredoxin 2,Glutaredoxin 3,Glutaredoxin 5,TTase-1,Thioltransferase,Thioltransferase-1,TTase 1,Thioltransferase 1