RT Journal Article
SR Electronic
T1 Redox response of iron-sulfur glutaredoxin GRXS17 activates its holdase activity to protect plants from heat stress
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.01.07.896506
DO 10.1101/2020.01.07.896506
A1 Laura Martins
A1 Johannes Knuesting
A1 Laetitia Bariat
A1 Avilien Dard
A1 Sven A. Freibert
A1 Christophe H. Marchand
A1 David Young
A1 Nguyen Ho Thuy Dung
A1 Anne Debures
A1 Julio Saez-Vasquez
A1 Stéphane D. Lemaire
A1 Roland Lill
A1 Joris Messens
A1 Renate Scheibe
A1 Jean-Philippe Reichheld
A1 Christophe Riondet
YR 2020
UL http://biorxiv.org/content/early/2020/01/07/2020.01.07.896506.abstract
AB Living organisms use a large panel of mechanisms to protect themselves from environmental stress. Particularly, heat stress induces misfolding and aggregation of proteins which are guarded by chaperone systems. Here, we examine the function the glutaredoxin GRXS17, a member of thiol reductases families in the model plant Arabidopsis thaliana. GRXS17 is a nucleocytosolic monothiol glutaredoxin consisting of an N-terminal thioredoxin (TRX)-domain and three CGFS-active site motif-containing GRX-domains that coordinate three iron-sulfur (Fe-S) clusters in a glutathione (GSH)-dependent manner. As a Fe-S cluster-charged holoenzyme, GRXS17 is likely involved in the maturation of cytosolic and nuclear Fe-S proteins. In addition to its role in cluster biogenesis, we showed that GRXS17 presents both foldase and redox-dependent holdase activities. Oxidative stress in combination with heat stress induces loss of its Fe-S clusters followed by subsequent formation of disulfide bonds between conserved active site cysteines in the corresponding TRX domains. This oxidation leads to a shift of GRXS17 to a high-MW complex and thus, activates its holdase activity. Moreover, we demonstrate that GRXS17 is specifically involved in plant tolerance to moderate high temperature and protects root meristematic cells from heat-induced cell death. Finally, we showed that upon heat stress, GRXS17 changes its client proteins, possibly to protect them from heat injuries. Therefore, we propose that the iron-sulfur cluster enzyme glutaredoxin GRXS17 is an essential guard to protect proteins against moderate heat stress, likely through a redox-dependent chaperone activity. All in all, we reveal the mechanism of an Fe-S cluster-dependent activity shift, turning the holoenzyme GRXS17 into a holdase that prevents damage caused by heat stress.