EvoLunch Seminar: Felix Frey (Institute of Science and Technology Austria, AT)

Lipid membranes define cells and structure their interiors. Here we study two distinct membrane designs that have evolved across the tree of life and their ability to remodel. (1) Plant endosomes are enclosed in flexible bilayer membranes, formed by single-headed lipids, from which small vesicles continuously pinch off. The reshaping of the endosomal membrane is mediated by filamentous proteins of the ESCRT-III family. Strikingly, in endosomes of flowering plant cells, arrays of concatenated membrane vesicles can form, which are connected either in parallel or in series with the membrane base. By combining computer simulations, continuum theory and electron tomography, we study the emerging budding patterns at plant endosomal membranes. (2) Archaea have membranes that can differ drastically in organization from bacteria and eukaryotes and typically contain mixtures of single-headed bilayer lipids and double-headed bolalipids. While this composition is believed to enable extremophile archaea to survive harsh environments, the physical mechanisms underlying the remodeling of archaeal membranes are often unknown. Through the development of a minimal computational model, we systematically explore the physical properties of archaeal membranes.