Fe-S Cluster Biogenesis in Plastids and Mitochondria in Plants

Iron-sulfur (Fe-S) clusters are essential, inorganic cofactors of Fe-S proteins involved in numerous vital developmental processes. Although simple in structure Fe-S clusters are not formed spontaneously but require an intricate interplay of a number of p roteins and in plants Fe-S cluster biogenesis takes place in both plastids and mitochondria. Although Fe-S cluster biogenesis in both organelles is vital for plant development little is known regarding the proteins involved. The objective of this proposal is to use cutting-edge molecular and cell biological tools to dissect Fe-S cluster biogenesis in plastids and mitochondria in Arabidopsis by functionally characterizing key SUF (mobilization of sulfur) and ISC (iron-sulfur-cluster) proteins. Using loss-o f-function mutants/inducible RNAi technology the role of the plastid-localized SUF protein AtSufC/AtNAP7, the plastid- and mitochondrial-localized AtSufE and the mitochondrial-localized ISC proteins AtHscA and AtHscB, will be determined throughout plant d evelopment. To determine the biochemical and cell biological properties of these proteins ATPase assays, subcellular localization studies (YFP fusion proteins, immunogold TEM studies) and protein-protein interaction experiments (Yeast two-hybrid, immunopr ecipitation, Bimolecular Fluorescence Complementation, Fluorescence Energy Resonance Transfer) will be conducted. To understand the coordination of Fe-S cluster biogenesis in plastids and mitochondria, organelle-targeted inactivation and detailed localisa tion studies will be performed using AtSufE. Although fundamental in nature, this research will lay the foundation for future research projects tailoring plants with increased resistance towards Fe-S cluster damage in response to UV irradiation and oxidat ive stresses. This research represents active collaborations between The University of Stavanger, University of Marburg (Germany), University of Munich (Germany) and University of Bergen (MIC).