Complex eukaryotic-like actin regulation systems from Asgard archaea

摘要: Asgard archaea genomes contain potential eukaryotic-like genes that provide intriguing insight for the evolution of eukaryotes. The actin polymerization/depolymerization cycle is critical providing force and structure a variety processes in eukaryotes, including membrane remodelling. Here, we identify filament severing, capping, annealing bundling, monomer sequestration activities by gelsolin proteins from Thorarchaeota (Thor), which complete eukaryote-like depolymerization cycle. Thor gelsolins are comprised one or two copies prototypical domain appear to be record an initial pre-eukaryotic gene duplication event, since eukaryotic generally three six domains. X-ray crystal determination these complex with mammalian revealed similar interactions first human gelsolin. two-domain, but not one-domain, calcium-binding sites, manifested calcium-controlled activities. Expression two-domain cells led enhanced disassembly on ionomycin-triggered calcium release. This functional demonstration, at cellular level, provides evidence calcium-regulated cytoskeleton archaea, indicates predates In dynamic bundled filaments responsible shaping filopodia microvilli. By correlation, formation protrusions observed Lokiarchaeota cell bodies may involve gelsolin-regulated structures.