The key topics of this section are protein folding and trafficking. These are two fundamental processes, which are most important for the structural organization and functioning of the cell. The availability of more and more genome sequences combined with genomics and proteomics analyses in prokaryotes and eukaryotes will lead to the emergence of unifying themes and system-specific aspects. The cross-discipline research (with groups in area A and C) will allow us to understand these different aspects and is reflected in the different expertise and scientific backgrounds of the scientists present in this cluster (e.g. cryo-electron microscopy, crystallography, atomic-force-microscopy, single molecule analysis, imaging of protein-protein-interactions). This will enable us to obtain an unprecedented view of the folding of proteins and the modulation of this process by molecular chaperones (Buchner, Hartl) of movement of proteins and other biopolymers within cells (Schliwa) and across membranes (Soll, Heesemann). We will focus on bacterial secretion (Heesemann, Weinkauf), the membranes of mitochondria (Neupert, Hell) and chloroplasts (Soll, Schleiff).