title: A dicotyledon-specific glutaredoxin GRXC1 family with dimer-dependent redox regulation is functionally redundant with GRXC2.
abstract: The major known function of glutaredoxins (Grxs) is to reduce disulphide bridges. Recently, some have also been shown to interact with iron-sulphur clusters. These can be classified in two subgroups: class II Grx are found in all living organisms and are implicated in assembly of iron-sulphur clusters, while class I Grx are represented by only two members known to form a holodimer structure containing a cluster in vitro, but with an unknown function different from class II. Here, we report that in eukaryotic plants, GRXC1 (class I) orthologs are exclusively present in dicotyledonous plants, suggesting a specific function. Indeed, in Arabidopsis thaliana, reducing activity of recombinant GRXC1 is regulated by redox-dependent stability of the cluster. In planta, GRXC1 has been found predominantly in a holodimeric form, indicating the presence of the cluster in vivo. This suggests that GRXC1 acts as a redox sensor, reducing downstream pathways under oxidative conditions. GRXC2, the closest homolog of GRXC1, is unable to form a cluster in vitro. Knock-out mutants in grxc1 or grxc2 are aphenotypic, but the double mutant produces a lethal phenotype at an early stage after pollinization, suggesting that GRXC1 and GRXC2 share redundant and vital functions.
authors.affiliation: Laboratoire Génome et Développement des Plantes, UMR 5096 CNRS-UPVD, 58 Avenue de Villeneuve - Bat T, 66860 Perpignan Cedex, France. christophe.riondet@univperp.fr
authors.forename: Christophe
authors.initials: C
authors.lastname: Riondet
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Desouris
authors.forename: Jocelyne Guilleminot
authors.initials: JG
authors.lastname: Montoya
authors.forename: Yvette
authors.initials: Y
authors.lastname: Chartier
authors.forename: Yves
authors.initials: Y
authors.lastname: Meyer
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Reichheld
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D005816:Genetic Complementation Test; D054477:Glutaredoxins / Q000235:genetics / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D019684:Magnoliopsida / Q000201:enzymology* / Q000235:genetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010641:Phenotype; D010802:Phylogeny; D054817:Pollination; D055503:Protein Multimerization; D055550:Protein Stability; D011994:Recombinant Proteins; D036226:Seedlings / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion
chemical_list: D029681:Arabidopsis Proteins; D054477:Glutaredoxins; D007506:Iron-Sulfur Proteins; D011994:Recombinant Proteins; D007501:Iron