Subproject 7

Transport and insertion mechanisms of plastid-encoded thylakoid membrane proteins

Project leader: Prof. Dr. Danja Schünemann

The biogenesis of photosynthetic protein complexes of the chloroplast thylakoid membrane requires highly specific protein sorting, integration and assembly mechanisms of nucleus as well as plastid encoded subunits. Central steps in the biogenesis of photosystem II (PS II) are the cotranslational insertion of the plastid encoded D1 protein into the thylakoid membrane and its subsequent assembly into functional PS II. Previous work indicated that soluble and membrane integral components of the chloroplast signal recognition particle (SRP)-dependent protein targeting machinery are involved in these processes. The aims of this proposal are (i) to unravel the function of these components in PS II biogenesis in higher plants on a detailed molecular level and to reveal differences to the prokaryotic SRP-dependent protein insertion and (ii) to get a comprehensive picture of transport mechanisms for chloroplast encoded thylakoid membrane proteins.