Post-translational regulation of ATP synthase assembly in chloroplasts

• Applicant: Privatdozent Dr. Thilo Fabian Rühle, Ph.D.
• Subject Area: Plant Physiology ; Plant Biochemistry and Biophysics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 500626297

ATP synthases in chloroplasts and cyanobacteria are nanomotors that harness the light-driven proton gradient across thylakoid membranes for ATP generation in photosynthesis. The structure and molecular function of thylakoid ATP synthases are well studied. One aim of current research is to optimize or specifically adapt their activity. However, structural modifications or adjustments of complex amounts require knowledge about the modular assembly process and the involved auxiliary factors, which can also play a role in the regulation of specific assembly steps.The project will therefore focus on an auxiliary factor (AtCGL160) from Arabidopsis that is responsible for the critical step in the recruitment of the stromal assembly module CF1. Mutant analysis, biochemical studies and genetic biosensors will be employed to investigate the influence of AtCGL160-dependent CF1 recruitment on chloroplast energetics. Furthermore, the complex between CF1 and the N-terminal domain of AtCGL160 will be structurally determined by high-resolution cryo-electron microscopy to elucidate the molecular mechanism of AtCGL160-dependent CF1 recruitment. In addition, the role of the suppressor PAF1 in ATP synthase assembly and its function as a possible antagonist to AtCGL160 will be investigated in Arabidopsis. Since PAF1-like proteins are also found in cyanobacteria, we will extend our analyses to Synechocystis and comparative studies will reveal evolutionary aspects of ATP synthase assembly between cyanobacteria and chloroplasts. As a long-term goal, the research project will elucidate regulatory principles of thylakoid ATP synthase assembly and provide elegant strategies for manipulating the ATP budget and proton circuits in photoautotrophic organisms.

• DFG Programme: Research Grants