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We all want to have a long life in good health. This is impossible without high quality food. Our group is interested in finding out how plants can grow well, even if environmental conditions are not optimal. This knowledge can help to provide farmers of the future with improved seed material for high quality and quantity harvests, as a basis for healthy human nutrition.
Adaptation of plants to changing environmental conditions requires sophisticated signal transduction and compensation strategies. Virtually all signal transduction pathways encompass steps to modify proteins already present in the cell. Such posttranslational modifications can occur by attaching a small protein to the substrate. The modifier proteins ubiquitin and small ubiquitin-related modifier (SUMO) are the focus of our research. We use biochemical and genetic tools to study modification pathways, in particular the N-degron (formerly N-end rule) pathway for ubiquitin conjugation, and a recently discovered pathway that links several SUMO proteins as a chain to the substrate. Both pathways have important functions in signal transduction for environmental adaptation.
Andreas Bachmair studied in Vienna, where he also got his PhD (with Helmut Ruis, 1984). After a postdoctoral stay with Alex Varshavsky (MIT, Cambridge, USA; 1985-1988), he stayed at the Max Planck Institute for Plant Breeding Research (Cologne, Germany) as a postdoc with Jeff Schell (1988-1991) and then joined the Institute of Botany of the University of Vienna (1991-2002). He moved to the Max Planck Institute for Plant Breeding Research (Cologne, Germany) as a group leader (2002-2008), before taking an Associate Professor position at the Max Perutz Labs. Since 2019, he is a full professor at the Max Perutz Labs.
The amino terminus of a protein is frequently modified, e.g. by addition of acetyl groups, or by proteolytic cleavage to generate the mature protein, or a protein variant. So-called N-recognins bind to amino termini to influence the protein half life. We are interested in N-recognins for amino-terminal Leu in plants. We identified mutants that stabilize a model protein with Leu amino terminus. Mutated genes are investigated to understand the biological significance of this protein degradation pathway.
Proteins can be covalently linked to SUMO. In most cases, one SUMO moiety is added. We have recently discovered that the SUMO conjugation machinery chooses specific proteins for attachment of SUMO chains, whereas other substrates obtain only single SUMO moieties (Tomanov et al., 2018, Biochem J 475: 61-68). A SUMO chain probably leads to proteolytic destruction of the substrate, due to the existence of SUMO chain binding ubiquitin ligases. We are studying this process with the help of mutants and in vitro reconstruction of the reaction.
The Scope, Functions, and Dynamics of Posttranslational Protein Modifications.
Millar, A Harvey; Heazlewood, Joshua L; Giglione, Carmela; Holdsworth, Michael J; Bachmair, Andreas; Schulze, Waltraud X
Sumoylation and phosphorylation: hidden and overt links.
Tomanov, Konstantin; Nukarinen, Ella; Vicente, Jorge; Mendiondo, Guillermina M; Winter, Nikola; Nehlin, Lilian; Weckwerth, Wolfram; Holdsworth, Michael J; Teige, Markus; Bachmair, Andreas
SUMO chain formation relies on the amino-terminal region of SUMO-conjugating enzyme and has dedicated substrates in plants.
Tomanov, Konstantin; Nehlin, Lilian; Ziba, Ionida; Bachmair, Andreas
Distinct branches of the N-end rule pathway modulate the plant immune response.
Vicente, Jorge; Mendiondo, Guillermina M; Pauwels, Jarne; Pastor, Victoria; Izquierdo, Yovanny; Naumann, Christin; Movahedi, Mahsa; Rooney, Daniel; Gibbs, Daniel J; Smart, Katherine; Bachmair, Andreas; Gray, Julie E; Dissmeyer, Nico; Castresana, Carmen; Ray, Rumiana V; Gevaert, Kris; Holdsworth, Michael J
FWF Special Research Program (SFB) F 7904 TP4 N-degron pathways in plants
Project title: “Novel tasks of the plant N-end rule degradation pathway" (P 31114)”
The project supports research on the N-end rule pathway. One specific research question is how proteins that carry an amino-terminal Leucine are degraded in plants.