Dr. Raya Sorkin
School of Chemistry, Tel-Aviv University, Israel
Fundamental understanding of physiological processes that occur at biological membranes, such as membrane fusion, necessitates addressing not only the biochemical aspects, but also biophysical aspects such as membrane mechanical properties and membrane curvature. In this talk, I will show how we combine membrane model systems, micropipette aspiration, optical tweezers and confocal fluorescence microscopy to study membrane shaping and membrane fusion processes. I will describe a new tool we developed, where we form membrane bilayers supported on polystyrene microspheres which can be trapped and manipulated using optical tweezers. Using this approach, we demonstrate successful measurements of the interaction forces between the Spike protein of SARS CoV-2 and its human receptor, ACE2. We further use bead-supported membranes interacted with aspirated vesicles to reveal the inhibitory effect of membrane tension on hemifusion. I will also describe a particular case of membrane shaping during the formation of the newly discovered organelle termed migrasome. We show that tetraspanin proteins involved in migrasome formation strongly partition into curved membrane tethers, and we reveal a novel, two-step process of migrasome biogenesis.