Enzymes of the Poly-(ADP-ribose)-polymerase (PARP) group influence signal transduction in response to both, attack by plant pathogens and adverse abiotic conditions such as drought, heat or high light stress. PARP proteins comprise an N-terminal sensor domain and a C-terminal catalytic domain. When activated by cellular stress conditions PARPs catalyse the covalent attachment of ADP-ribose units onto themselves and onto target proteins. We aim to obtain a better understanding of how this post-translational modification affects plant stress responses.
In addition to the canonical PARPs that are conserved in higher eukaryotes plants evolved a unique group of PARP-like proteins. These proteins are characterized by a central PARP-like domain but differ from canonical PARPs in their N- and C-terminal domains. Arabidopsis RCD1, the founding member of this protein family, lacks enzymatic activity. Nevertheless RCD1 and sequence-related proteins from rice and wheat also influence stress responses. We aim to elucidate how RCD1-type proteins affect plant stress signalling at the level of transcriptional regulation.
To gain a better understanding of plant PARPs and PARP-like proteins we use state-of-the-art molecular biology tools and plant stress assays. We also aim to obtain structural information on PARPs and PARP-like proteins to build a molecular framework that will allow us to understand the molecular function of these proteins in signal transduction. For a structural characterization of PARPs and PARP-like proteins we collaborate with the group of Prof. Markus Wahl at FU Berlin and the BESSY II synchrotron at Helmholtz Centre Berlin.