Multiscale (re)modeling of lipid bilayer membranes

Many phenomena of biological membranes are inherently multi-scalar: their observation and description requires very different length and time-scales. Especially membrane remodeling processes that are essential for many important cellular activities, such as endo- and exocytosis, cell division, infection, immune response or cell-cell communication, involve large scale morphological changes of the membrane, which are initiated and controlled by molecular scale interactions. The large-scale behavior of the membrane is intimately coupled to the atomic detail of the system, so that for a successful model, the contributions at all scales have to be included. This chapter gives an overview of the computational methods used to model lipid bilayer membranes and their interactions with proteins and other molecules at different levels of resolution. Then strategies to connect the models at different scales in order to provide a multi-resolution picture are described. Methods to quantify free energy changes associated with complex collective rearrangement are outlined. The last sections summarize examples for the application of these methods to pore formation, reshaping membranes into buds and membrane tubes as well as membrane fusion