The plastidial Arabidopsis thaliana NFU1 protein binds and delivers [4Fe-4S] clusters to specific client proteins

The plastidial Arabidopsis thaliana NFU1 protein binds and delivers [4Fe-4S] clusters to specific client proteins

Mélanie Roland (1) , Jonathan Przybyla-Toscano (1) , Florence Vignols (2) , Nathalie Berger (2) , Tamanna Azam (3) , Loïck Christ (1) , Veronique Santoni (2) , Hui-Chen Wu (2) , Tiphaine Dhalleine (1) , Michael K. Johnson (3) , Christian Dubos (2) , Jérémy Couturier (1) , Nicolas Rouhier (1)

1 IAM - Interactions Arbres-Microorganismes
2 BPMP - Biochimie et Physiologie Moléculaire des Plantes
3 Department of Chemistry and Center for Metalloenzyme Studies

Proteins incorporating iron-sulfur (Fe-S) co-factors are required for a plethora of metabolic processes. Their maturation depends on three Fe-S cluster assembly machineries in plants, located in the cytosol, mitochondria, and chloroplasts. After de novo formation on scaffold proteins, transfer proteins load Fe-S clusters onto client proteins. Among the plastidial representatives of these transfer proteins, NFU2 and NFU3 are required for the maturation of the [4Fe-4S] clusters present in photosystem I subunits, acting upstream of the high-chlorophyll fluorescence 101 (HCF101) protein. NFU2 is also required for the maturation of the [2Fe-2S]-containing dihydroxyacid dehydratase, important for branched-chain amino acid synthesis. Here, we report that recombinant Arabidopsis thaliana NFU1 assembles one [4Fe-4S] cluster per homodimer. Performing co-immunoprecipitation experiments and assessing physical interactions of NFU1 with many [4Fe-4S]-containing plastidial proteins in binary yeast two-hybrid assays, we also gained insights into the specificity of NFU1 for the maturation of chloroplastic Fe-S proteins. Using bimolecular fluorescence complementation and in vitro Fe-S cluster transfer experiments, we confirmed interactions with two proteins involved in isoprenoid and thiamine biosynthesis, 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase and 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate synthase, respectively. An additional interaction detected with the scaffold protein SUFD enabled us to build a model in which NFU1 receives its Fe-S cluster from the SUFBC2D scaffold complex and serves in the maturation of specific [4Fe-4S] client proteins. The identification of the NFU1 partner proteins reported here more clearly defines the role of NFU1 in Fe-S client protein maturation in Arabidopsis chloroplasts among other SUF components.

Mots clés: sulfur; maturation; protein assembly; chloroplast; iron–sulfur protein; Arabidopsis thaliana; NFU; iron-sulfur cluster; protein maturation; transfer protein; sulfur mobilization (SUF); scaffold protein; plant metabolism; protein-protein interaction

Domaines: Biologie végétale; Sciences du Vivant [q-bio]

Mélanie Roland, Jonathan Przybyla-Toscano, Florence Vignols, Nathalie Berger, Tamanna Azam, et al.. The plastidial Arabidopsis thaliana NFU1 protein binds and delivers [4Fe-4S] clusters to specific client proteins. Journal of Biological Chemistry, 2020, 295 (6), pp.1727-1742. ⟨10.1074/jbc.RA119.011034⟩. ⟨hal-02473677⟩