start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page=117 end-page=33 dt-received= dt-revised= dt-accepted= dt-pub-year=2020 dt-pub=20200818 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Insights into the evolution of regulated actin dynamics via characterization of primitive gelsolin/cofilin proteins from Asgard archaea en-subtitle= kn-subtitle= en-abstract= kn-abstract=Asgard archaea genomes contain potential eukaryotic-like genes that provide intriguing insight for the evolution of eukaryotes. The eukaryotic actin polymerization/depolymerization cycle is critical for providing force and structure in many processes, including membrane remodeling. In general, Asgard genomes encode two classes of actin-regulating proteins from sequence analysis, profilins and gelsolins. Asgard profilins were demonstrated to regulate actin filament nucleation. Here, we identify actin filament severing, capping, annealing and bundling, and monomer sequestration activities by gelsolin proteins from Thorarchaeota (Thor), which complete a eukaryotic-like actin depolymerization cycle, and indicate complex actin cytoskeleton regulation in Asgard organisms. Thor gelsolins have homologs in other Asgard archaea and comprise one or two copies of the prototypical gelsolin domain. This appears to be a record of an initial preeukaryotic gene duplication event, since eukaryotic gelsolins are generally comprise three to six domains. X-ray structures of these proteins in complex with mammalian actin revealed similar interactions to the first domain of human gelsolin or cofilin with actin. Asgard two-domain, but not one-domain, gelsolins contain calcium-binding sites, which is manifested in calcium-controlled activities. Expression of two-domain gelsolins in mammalian cells enhanced actin filament disassembly on ionomycin-triggered calcium release. This functional demonstration, at the cellular level, provides evidence for a calcium-controlled Asgard actin cytoskeleton, indicating that the calcium-regulated actin cytoskeleton predates eukaryotes. In eukaryotes, dynamic bundled actin filaments are responsible for shaping filopodia and microvilli. By correlation, we hypothesize that the formation of the protrusions observed from Lokiarchaeota cell bodies may involve the gelsolin-regulated actin structures. en-copyright= kn-copyright= en-aut-name=Ak?lCaner en-aut-sei=Ak?l en-aut-mei=Caner kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=TranLinh T. en-aut-sei=Tran en-aut-mei=Linh T. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=Orhant-PriouxMagali en-aut-sei=Orhant-Prioux en-aut-mei=Magali kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=BaskaranYohendran en-aut-sei=Baskaran en-aut-mei=Yohendran kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=ManserEdward en-aut-sei=Manser en-aut-mei=Edward kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=BlanchoinLaurent en-aut-sei=Blanchoin en-aut-mei=Laurent kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=RobinsonRobert C. en-aut-sei=Robinson en-aut-mei=Robert C. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Institute of Molecular and Cell Biology, Agency for Science, Technology and Research kn-affil= affil-num=2 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=3 en-affil=CytomorphoLab, Interdisciplinary Research Institute of Grenoble kn-affil= affil-num=4 en-affil=aInstitute of Molecular and Cell Biology, Agency for Science, Technology and Research kn-affil= affil-num=5 en-affil=aInstitute of Molecular and Cell Biology, Agency for Science, Technology and Research kn-affil= affil-num=6 en-affil=CytomorphoLab, Interdisciplinary Research Institute of Grenoble kn-affil= affil-num=7 en-affil=cResearch Institute for Interdisciplinary Science, Okayama University kn-affil= en-keyword=actin kn-keyword=actin en-keyword=gelsolin kn-keyword=gelsolin en-keyword=Asgard archaea kn-keyword=Asgard archaea en-keyword=eukaryogenesis kn-keyword=eukaryogenesis en-keyword=X-ray crystallography kn-keyword=X-ray crystallography END