ReMembrane · How do tetraspanin proteins organize, shape, and remodel biological membranes?

Our bodies rely on protein driven shaping and remodelling of our cells’ membranes to function. Uncovering the mechanisms of remodelling of the cell membrane is, therefore, essential for understanding biological processes such as fertilization, but also to allow for precise intervention in them when needed. The interplay between protein position, membrane tension, and local curvature is believed to dictate these processes. However, experimental verifications of this hypothesis in specific biological systems are scarce. Here, I propose to apply my expertise in the characterization of mechanical properties and remodelling of membranes to obtain ground-breaking quantitative details of the shaping and remodelling mechanisms in which the Tetraspanin (TSPN) family of proteins are involved. TSPNs provide an ideal case study for several reasons, they are of extreme importance to biological processes such as viral infection, they are well characterized by biochemical, genetic and proteomics approaches, and their mode of action is suspected to depend on membrane tension and curvature. Of specific interest is the role of TSPN in the formation of the newly discovered cellular organelles, called migrasomes, which are a new cell-cell communication paradigm. This proposed project addresses TSPN functions by a bottom-up approach, reconstituting the processes of interest from simple building blocks and characterizing the distinguished roles of membrane tension and curvature. To this end we will use several new assays based on combined optical tweezers, micropipette aspiration and confocal microscopy as well as AFM that will operate on crafted membrane model systems. Our unique experimental approach will allow us to recreate the conditions leading to migrasome formation, egg-sperm, and viral membrane fusion. Revealing the mechanisms underlying these processes will have direct impact on the development of infertility treatments, non-hormonal contraceptives, and novel anti-viral drugs.