PD Dr. Bettina Bölter
1. Characterisation of protein transport into chloroplasts - analysis of composition and regulation of translocation complexes
Chloroplasts are semi-autonomous endosymbiotic organelles, which depend on the post-translational import of proteins from the cytosol. Protein translocation into chloroplasts is mediated by two multi-subunit complexes in the outer (TOC) and the inner (TIC) envelope membrane, which constitute the general import pathway. Other routes into the chloroplast seem to exist but knowledge about these is scarce. The process of protein import needs to be tightly regulated at several levels to ensure that all needs of the chloroplast and the surrounding cell are met at any given time.
Our group works on the characterisation of the import process and analysis of the TIC complex composition as well as on the function of the individual components. We are especially interested in import regulation at the level of TIC and how signals are transferred to the surrounding cell. We could recently show that the redox status of the organelle is a crucial parameter for import activity and TIC composition. It connects fundamental metabolic functions in the chloroplasts with the fine-tuning of protein import, showing the potential to react in a very complex manner to primary metabolism and environmental changes.
2. Characterisation of metabolite transport across the Chloroplast outer envelope membrane
Besides photosynthesis chloroplast perform a multitude of biosynthetic processes, such as synthesis of amino and fatty acid as well as of secondary compounds. On the one hand, these metabolites need to be transported to the surrounding cell; on the other hand, chloroplasts require “building material” from other compartments in the cell. Therefore, a massive exchange of metabolites via either transporter proteins in the inner envelope or channel proteins in the outer envelope membrane takes place.
Our group especially focusses on the identification and analysis of channel proteins in the outer chloroplast membrane. Within the SFB-TR175 we study how regulation of metabolite transport is achieved under changing environmental conditions.
PD Dr. Bettina Bölter (group leader)
Petra Schuhmann (PhD student)
Melanie Barth (PhD Student)
Sebnem Akbas (PhD Student)
Beate Häusler (technical personnel)
Franka Andersch (technical personnel)