Asgard archaea shed light on the evolutionary origins of the eukaryotic ubiquitin-ESCRT machinery

Hatano, Tomoyuki and Palani, Saravanan and Papatziamou, Dimitra and Salzer, Ralf and Souza, Diorge P. and Tamarit, Daniel and Makwana, Mehul and Potter, Antonia and Haig, Alexandra and Xu, Wenjue and Townsend, David and Rochester, David and Bellini, Dom and Hussain, Hamdi M. A. and Ettema, Thijs J. G. and Löwe, Jan and Baum, Buzz and Robinson, Nicholas P. and Balasubramanian, Mohan (2022) Asgard archaea shed light on the evolutionary origins of the eukaryotic ubiquitin-ESCRT machinery. Nature Communications, 13 (1). ISSN 2041-1723

Abstract

The ESCRT machinery, comprising of multiple proteins and subcomplexes, is crucial for membrane remodelling in eukaryotic cells, in processes that include ubiquitin-mediated multivesicular body formation, membrane repair, cytokinetic abscission, and virus exit from host cells. This ESCRT system appears to have simpler, ancient origins, since many archaeal species possess homologues of ESCRT-III and Vps4, the components that execute the final membrane scission reaction, where they have been shown to play roles in cytokinesis, extracellular vesicle formation and viral egress. Remarkably, metagenome assemblies of Asgard archaea, the closest known living relatives of eukaryotes, were recently shown to encode homologues of the entire cascade involved in ubiquitin-mediated membrane remodelling, including ubiquitin itself, components of the ESCRT-I and ESCRT-II subcomplexes, and ESCRT-III and Vps4. Here, we explore the phylogeny, structure, and biochemistry of Asgard homologues of the ESCRT machinery and the associated ubiquitylation system. We provide evidence for the ESCRT-I and ESCRT-II subcomplexes being involved in ubiquitin-directed recruitment of ESCRT-III, as it is in eukaryotes. Taken together, our analyses suggest a pre-eukaryotic origin for the ubiquitin-coupled ESCRT system and a likely path of ESCRT evolution via a series of gene duplication and diversification events.