Assembly of a prokaryotic organelle by Tic20-like proteins

• Applicant: Dr. Rene Uebe
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 414946895

The biogenesis and assembly of membranous cell organelles requires a multitude of processes, including membrane remodeling and correct spatio-temporal targeting of proteins. While these processes are relatively well characterized in eukaryotes, the biogenesis and assembly of prokaryotic organelles is often still poorly understood. In this project, I aim to analyze the protein assembly of magnetosomes, unique magnetic organelles from magnetotactic bacteria. My preliminary results indicate that MamF-like proteins which are related to Tic20, a protein translocating channel of the inner membrane of chloroplasts, play a central role during the protein assembly of magnetosomes. To understand their roles during magnetosome assembly we will first identify all proteins that are mistargeted in a mutant lacking all mamF-like genes by proteomic and immunochemical analyses. Subsequently, we will determine if these putative substrates directly interact with MamF-like proteins using bacterial two-hybrid assays and PAGE-based methods. After identification of MM targeting determinants within substrate and MamF-like proteins, we will establish a fluorescence microscopic magnetosome targeting assay to identify the mechanism and timing of the MamF-mediated magnetosome membrane assembly. Subsequently, we aim verify the targeting mechanism using microscopic, physiologic, or biochemical methods. Finally, our functional characterization of these Tic20-related MamF-like proteins will not only be important to generally understand protein targeting to a prokaryotic organelle but also help to elucidate the roles of Tic20-like proteins in non-photosynthetic organisms and shed new lights in the evolution of organelle-specific protein translocons in eukaryotes.

• DFG Programme: Research Grants