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Unravelling new metal- or redox-dependent proteins and processes in plants

PI: Nicolas Rouhier (UMR 1136 Interactions Arbres/Microorganismes — IAM)

Pr Roland Lill (Univ. of Marburg), Pr Johannes Herrmann (Univ. of Kaiserslautern), Dr Claude Didierjean (Université de Lorraine), Dr Pascal Rey (CEA Cadarache, AMU) ; Dr Jean Philippe Reichheld (Univ. of Perpignan); Pr Andreas J. Meyer (Univ. of Bonn), Dr Janneke Balk (John Innes Centre and University of East Anglia); Dr Frédéric Gaymard (INRA/Univ of Montpellier).


Context — Major cellular functions are controlled at several steps through oxidoreduction reactions including electron transfer reactions catalyzed by metalloproteins, notably iron and copper-containing proteins, and by thiol-containing proteins in the case of dithiol-disulfide exchanges. By controlling several developmental stages, the photosynthetic rates and several aspects of the stress responses, these redox mechanisms are particularly crucial in plants. Cysteinyl residues are central to these reactions serving as catalytic or redox centers, as metal ligands or as regulatory switches through their capacity to adopt several oxidation states in proteins in response to different redox signals.

Objectives — While there is no unique protein signature, the CXXC motifs are particularly suited for disulfide bond formation and for the coordination of metals as exemplified by the Fe2S2 centers found in ferredoxins. Thus, by identifying and characterizing proteins of unknown function and possessing one or several conserved CXXC motifs, the global objective of the MetOx proposal is to identify new redox-regulated or metal-binding proteins.

Approach — From the in silico analyses of several plant genomes, we will select about 50 candidate proteins and perform a thorough biochemical and structural characterization of the corresponding recombinant proteins, before deciphering the biological roles of the most promising candidates using genetic approaches.

Expected results and impacts — We anticipate that the proposed approach will allow (i) unravelling new redox-regulated cellular processes or signaling pathways in poplar and more generally in plants which are controlled by redox reactions i.e., assisted by thiol-disulfide exchanges or by metalloproteins and (ii) understanding how the functions of these proteins are controlled at the cellular level.