Research interests

Cells in plants are constantly challenged by environmental stress factors and developmental changes. The homeostasis of metabolic pathways participates in the perception of external signals (e.g. redox control) and forms the basis for cellular and developmental adaptation. Plants are excellent model systems to study fundamental questions of cellular regulation. Sulfur metabolism provides such an example due to its essential function in provision of sulfur amino acids and contribution to abiotic and biotic stress resistance. The sensing and signal transduction of homeotic distubances and adaptive responses in this central pathway is investigated in Arabidopsis thaliana at the molecular and biochemical level. Complete genome sequence, mutant collections, easy genetics and transformation make the world-wide Arabidopsis community a leading force of basic research.

Our research at the Heidelberg Institute for Plant Sciences focuses on three aspects. First, the function of the oligo-heteromeric cysteine synthase complex in sensing of the reduced sulfur status is investigated. The fluctuating concentrations of two sulfur-related metabolites drive the equilibrium of complex formation and catalytic activities of the protein subunits. Second, subcellular compartmentation of sulfur metabolism, membrane transport and regulatory interaction of sulfate reduction and sulfur amino acid sbiosynthesis are investigated. Mutagenesis, protein modeling, crystallization, flux analyses, fluorescence resonance energy transfer and celluar compartmentation are used in this project. Third, redox homoeostasis and redox signaling are important elementes of communication between cells and their environment. Glutathione reductase mutants, live cell imaging of redox potential and intracellular communication are topics of this project. Finally, co-translational protein N-acetylation is a common maturation process in the cytosol of eukaryotic cells but less understood with respect to mechanism, function and protein quality. We analyse this process using plant yand east loss of function mutants.

 

Methods applied

Protein and metabolite biochemistry HPLC, mass spectrometry, proteomics, protein analytics, protein interaction, mutagenesis; confocal microscopy/live cell imaging of metabolites, FRET; genetic transformation of plants, yeast, bacteria; isotope labeling, metabolite flux analysis.