Etablishing the role of glutaredoxins in mitochondrial redox homeostasis and associated plant cell function
Final Report Abstract
Glutaredoxins (Grx) are small ubiquitous enzymes, generally involved in re-reduction of diverse oxidative modifications using glutathione. In recent years data has accumulated about the important role Grx play in the cellular redox network, especially under certain stress conditions which promote oxidation of protein thiols. In order to gain a better understanding of how energy metabolism and redox regulation mediated by Grxs are linked, mitochondria are of specific interest. Despite evidence for multiple Grxs in Arabidopsis mitochondria, combined analysis of subcellular localisation of GFP fusion proteins and proteomics of isolated mitochondria has shown that there is really only one key player, AtGrxS15. In order to uncover the impact of AtGrxS15 in Arabidopsis mitochondria different in vitro and in vivo experimental approaches were employed. A AtGrxS15 T-DNA insertion line with modified 5’ UTR leads to altered expression patterns of the two splice variants and subsequently to a knockdown at the protein level. The reduced amount of AtGrxS15 results in a growth phenotype with significantly shorter roots compared to wildtype plants. A mitochondrial-focused stress, application of the complex III specific inhibitor Antimycin A, leads to even shorter roots for the transgenic line. Different forms of arsenic promote the generation of an even stronger growth phenotype with an additional effect on the leaves. The AtGrxS15 T-DNA insertion line shows smaller rosettes compared to wildtype plants. These results indicate that mitochondria are involved in the detoxification of arsenic compounds, and moreover reveal that AtGrxS15 is a crucial element within this pathway. Taken together these findings have greatly improved the current understanding of Grx function in plant mitochondria.
Publications
- „Establishing the role of Glutaredoxins in mitochondrial redox homeostasis and associated plant cell function“, Society for Experimental Botany (SEB) Annual Main Meeting in Prague, Czech Republic, 30.06.2010 to 03.07.2010
- „Knockdown of mitochondrial-located Glutaredoxin S15 reveals a role in tolerance to ETC inhibition and arsenic toxicity“, International Conference for Plant Mitochondrial Biology (ICPMB), Hohenroda, Germany, 14.5.2011 to 19.5.2011
