title: Redox control of Hsp70-Co-chaperone interaction revealed by expression of a thioredoxin-like Arabidopsis protein.
abstract: By using a yeast functional complementation assay, we have identified AtTDX, a new Arabidopsis thaliana gene, encoding a two-domain 42-kDa protein. The amino-terminal domain of AtTDX is closely related to the co-chaperone Hsp70-interacting protein HIP, whereas its carboxyl-terminal part contains a thioredoxin domain. Both in vivo and in vitro assays showed that AtTDX is a protein-disulfide reductase. We next found that the HIP domain of AtTDX is capable of interacting with the ATPase domain of Ssb2, a yeast heat-shock protein 70 chaperone. Strikingly, the AtTDX-Ssb2 interaction can be released under oxidative stress, a redox-dependent regulation involving the thioredoxin activity of AtTDX. A mutation inactivating the cysteine 20 of the ATPase domain of Ssb2 was found to stabilize the AtTDX-Ssb2 interaction that becomes redox-insensitive. As cysteine 20 is conserved in virtually all the Hsp70 chaperones, our results suggest that this residue might be more generally the target of redox regulations of chaperone binding activity.
authors.affiliation: Laboratoire Génome et Développement des Plantes, CNRS, UMR 5096, Université de Perpignan, 52 Avenue de Villeneuve, 66860 Perpignan, France. vignols@univ-perp.fr
authors.forename: Florence
authors.initials: F
authors.lastname: Vignols
authors.forename: Nabil
authors.initials: N
authors.lastname: Mouaheb
authors.forename: Dominique
authors.initials: D
authors.lastname: Thomas
authors.forename: Yves
authors.initials: Y
authors.lastname: Meyer
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae; D013879:Thioredoxins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C504764:AtTDX protein, Arabidopsis; D018840:HSP70 Heat-Shock Proteins; C105426:Hip chaperone; D018832:Molecular Chaperones; D010940:Plant Proteins; D013879:Thioredoxins