Bridging the lipid divide: archaeal ESCRT-III binds phosphoinositol and polarises the cytokinetic membrane

Abstract

All cells remodel their membranes to divide. The highly conserved ESCRT-III system forms contractile polymers which, through direct interactions with membrane lipids, remodel membranes across the tree of life. In exploring how ESCRT-III divides the chemically and structurally unique archaeal membrane, we reveal that the homologue CdvB1 is required for the establishment of a distinct membrane domain within the division bridge of Sulfolobus acidocaldarius, associated with an accumulation of membrane-spanning inositol phosphate lipids. We show that CdvB1 associates with phosphoinositides in vitro and that this interaction aids cytokinesis in vivo. Together, we suggest that although eukaryotes inherited their membrane lipids from bacteria during eukaryogenesis, key features of the ESCRT-III:membrane interface that allow these polymers to bind, organise, and remodel eukaryotic membranes, may originate in archaea.