The compartmentalization of cells ensures a highly specific distribution of nucleic acids, proteins and metabolites. At the same time, intracellular compartments must communicate and exchange molecules. Two major systems enable exchange between compartments: compartmental gates and contact sites. While compartmental gates mediate the selective partitioning of molecules between cytoplasm and organelles or within a membrane, contact sites represent direct physical connections between compartment-enclosing membranes. Thus, within living cells, compartmental gates and contact sites represent two complementary systems, which functionally cooperate or directly interact with each other to coordinate compartmentalized processes. The SFB1190 is committed to addressing the role of compartmental gates and contact sites in cellular organization and physiology. We aim to understand how they achieve a selective distribution of molecules and thus functionally define and diversify cellular compartments.