Coevolution of Eukaryote-like Vps4 and ESCRT-III Subunits in the Asgard Archaea

The emergence of the endomembrane system is a key step in the evolution of cellular complexity during eukaryogenesis. The endosomal sorting complex required for transport (ESCRT) machinery is essential and required for the endomembrane system functions in eukaryotic cells. Recently, genes encoding eukaryote-like ESCRT protein components have been identified in the genomes of Asgard archaea, a newly proposed archaeal superphylum that is thought to include the closest extant prokaryotic relatives of eukaryotes. However, structural and functional features of Asgard ESCRT remain uncharacterized. Here, we show that Vps4, Vps2/24/46, and Vps20/32/60, the core functional components of the Asgard ESCRT, coevolved eukaryote-like structural and functional features. Phylogenetic analysis shows that Asgard Vps4, Vps2/24/46, and Vps20/32/60 are closely related to their eukaryotic counterparts. Molecular dynamics simulation and biochemical assays indicate that Asgard Vps4 contains a eukaryote-like microtubule-interacting and transport (MIT) domain that binds the distinct type 1 MIT-interacting motif and type 2 MIT-interacting motif in Vps2/24/46 and Vps20/32/60, respectively. The Asgard Vps4 partly, but much more efficiently than homologs from other archaea, complements the vps4 null mutant of Saccharomyces cerevisiae, further supporting the functional similarity between the membrane remodeling machineries of Asgard archaea and eukaryotes. Thus, this work provides evidence that the ESCRT complexes from Asgard archaea and eukaryotes are evolutionarily related and functionally similar. Thus, despite the apparent absence of endomembranes in Asgard archaea, the eukaryotic ESCRT seems to have been directly inherited from an Asgard ancestor, to become a key component of the emerging endomembrane system.