University of Geneva, Switzerland
19 October 2020, 15:30:00
The unique ESCRT-III mechanics that drives membrane remodelling
ESCRT-III is the most ancient membrane remodelling machineries as it is the only one present in Archaea, and are thought to be essential for the creation and maintenance of an endomembrane system. As a matter of facts, it is the only machinery that can work on every membrane: ER, endosomes/lysosomes, plasma membrane, but also the autophagosome and pathogen’s vacuoles. In opposition to other machineries such as Cathrin or COPs, ESCRT-III is composed of small subunits all sharing the same biochemical structure, making difficult to apprehend the structure/function link. By reconstituting in vitro ESCRT-III mediated membrane deformation and fission, we will discuss the mechanism by which ESCRT-III is dynamically remodelling membranes. In particular, we will show that sequential assembly of helical filaments with different dimensions, orientations to the membrane and rigidities, drives deformation and then fission. We will then discuss the essential biochemical activities required for this function, and should be common to all species, from Archaea to mammals.