Membrane Organization and Contact Sites
Biological membranes are crucial for life. The plasma membrane forms a lipid-based barrier that protects the cell from its environment, while a dedicated set of membrane proteins allow for selective material exchange between the cytosol and the extracellular space. In eukaryotic cells, additional internal membranes enable the formation of intracellular compartments with defined biochemical functions, the organelles.
Different types of membranes are characterized by fundamentally distinct protein and lipid compositions, which is the molecular basis for their unique functions. Structural and compositional variation is not only observed between distinct membranes, but can also occur within one continuous membrane, resulting in formation of specialized membrane subdomains. Such heterogeneity within one membrane is brought about by a transient or temporally persistent lateral organization of membrane components. Membrane subdomains can for example be defined by their protein and/or lipid composition, as observed in membrane rafts, by curvature, such as seen in tubular and flat regions of many organelle membranes, or by function, such as local secretion hotspots in the endoplasmic reticulum, or respiration hotspots in specialized regions of the mitochondrial inner membrane.
A special type of membrane subdomains are membrane contact sites. These are defined places where different types of membranes are physically attached to each other via proteinaceous tether machineries. Membrane contact sites are equipped with a unique set of resident molecules, and fulfill numerous biological functions, including direct inter-organelle material transport, signaling, and organelle membrane dynamics and inheritance.
As one of the workgroups within the DGZ we aim to provide a platform for regular exchanges between researchers in this very active area of cell biology, connect junior scientists with the community in Germany and provide a regular food-for-thoughts meeting, in pandemic times and beyond.