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

• DOI: 10.1093/plphys/kiab172
• Publication Date: 2021-04-13T17:29:50Z
• Authors: Anna Moseler; Inga Kruse; Andrew E Maclean; Luca Pedroletti; Marina Franceschetti; Stephan Wagner; Regina Wehler; Katrin Fischer-Sc...; Gernot Poschet; Markus Wirtz; Peter Dörmann; Tatjana M Hildebr...; Rüdiger Hell; Markus Schwarzländer; Janneke Balk; Andreas J Meyer
• Keywords: Mitochondrial matrix

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