The evolution and mechanism of bacterial and archaeal ESCRT-III-like systems

The endosomal sorting complex required for transport-III (ESCRT-III) system is an ancient protein family involved in membrane remodelling. Recent phylogenetic and structural analyses reveal its conservation across the tree of life, including bacteria and archaea, suggesting an evolutionary origin predating the last universal common ancestor. These findings underscore the importance of the ESCRT-III superfamily to our origins, particularly with the recognition of their contribution to eukaryogenesis through the Asgard archaea lineage. Bacterial systems, often with a single ESCRT-III-like protein, offer a simple model for understanding how ESCRT-III can function as both membrane sensor and sculptor. This review explores the structural dynamics, evolutionary trajectories, and biological significance of ESCRT-III in bacteria and archaea. We describe how ESCRT-III polymerises and assembles conserved filaments with the coating of flat or positively curved membranes prevalent, at least in vitro. Finally, we highlight common mechanistic principles and unique adaptations that enable ESCRT-III systems to support diverse cellular processes across evolutionary domains.