Wikipedia - Benutzerbeiträge [de]

Benutzer:Petra Delius/Gelsolin

2020-11-17T08:12:10Z

131.112.112.6:

{{Infobox_gene}}
'''Gelsolin''' is an [[actin]]-binding protein that is a key regulator of actin filament assembly and disassembly. Gelsolin is one of the most potent members of the actin-severing gelsolin/[[villin]] superfamily, as it severs with nearly 100% efficiency.<ref name="pmid24155256">{{cite journal | vauthors = Ghoshdastider U, Popp D, Burtnick LD, Robinson RC | title = The expanding superfamily of gelsolin homology domain proteins | journal = Cytoskeleton | volume = 70 | issue = 11 | pages = 775–95 | date = November 2013 | pmid = 24155256 | doi = 10.1002/cm.21149 | s2cid = 205643538 }}</ref><ref name="Sun">{{cite journal | vauthors = Sun HQ, Yamamoto M, Mejillano M, Yin HL | title = Gelsolin, a multifunctional actin regulatory protein | journal = The Journal of Biological Chemistry | volume = 274 | issue = 47 | pages = 33179–82 | date = November 1999 | pmid = 10559185 | doi = 10.1074/jbc.274.47.33179 | doi-access = free }}</ref>

Cellular gelsolin, found within the [[cytosol]] and [[mitochondria]],<ref name="Koya">{{cite journal | vauthors = Koya RC, Fujita H, Shimizu S, Ohtsu M, Takimoto M, Tsujimoto Y, Kuzumaki N | title = Gelsolin inhibits apoptosis by blocking mitochondrial membrane potential loss and cytochrome c release | journal = The Journal of Biological Chemistry | volume = 275 | issue = 20 | pages = 15343–9 | date = May 2000 | pmid = 10809769 | doi = 10.1074/jbc.275.20.15343 | doi-access = free }}</ref> has a closely related secreted form, [[Plasma gelsolin]], that contains an additional 24 AA N-terminal extension.<ref name=Kwiatkowski1986>{{cite journal | vauthors = Kwiatkowski DJ, Stossel TP, Orkin SH, Mole JE, Colten HR, Yin HL | title = Plasma and cytoplasmic gelsolins are encoded by a single gene and contain a duplicated actin-binding domain | journal = Nature | volume = 323 | issue = 6087 | pages = 455–8 | date = 1986-10-02 | pmid = 3020431 | doi = 10.1038/323455a0 | s2cid = 4356162 | bibcode = 1986Natur.323..455K }}</ref><ref name="Nag2013Gymnast">{{cite journal | vauthors = Nag S, Larsson M, Robinson RC, Burtnick LD | title = Gelsolin: the tail of a molecular gymnast | journal = Cytoskeleton | volume = 70 | issue = 7 | pages = 360–84 | date = July 2013 | pmid = 23749648 | doi = 10.1002/cm.21117 | s2cid = 23646422 }}</ref> Plasma gelsolin's ability to sever [[Actin#F-Actin|actin filaments]] helps the body recover from disease and injury that leaks cellular actin into the blood. Additionally it plays important roles in host [[Innate immune system|innate immunity]], activating [[macrophages]] and localizing of [[inflammation]].

== Structure ==

{{Infobox protein family
| align = left
| Symbol = Gelsolin
| Name = Gelsolin
| image = PDB 1pd0 EBI.jpg
| width =
| caption = crystal structure of the copii coat subunit, sec24, complexed with a peptide from the snare protein sed5 (yeast syntaxin-5)
| Pfam = PF00626
| Pfam_clan = CL0092
| InterPro = IPR007123
| SMART =
| PROSITE =
| MEROPS =
| SCOP = 1vil
| TCDB =
| OPM family =
| OPM protein =
| CAZy =
| CDD =
}}
Gelsolin is an 82-kD protein with six homologous subdomains, referred to as S1-S6. Each subdomain is composed of a five-stranded [[β-sheet]], flanked by two [[α-helix|α-helices]], one positioned perpendicular with respect to the strands and one positioned parallel. The β-sheets of the three [[N-terminal]] subdomains (S1-S3) join to form an extended β-sheet, as do the β-sheets of the [[C-terminal]] subdomains (S4-S6).<ref name="Kiselar">{{cite journal | vauthors = Kiselar JG, Janmey PA, Almo SC, Chance MR | title = Visualizing the Ca2+-dependent activation of gelsolin by using synchrotron footprinting | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 100 | issue = 7 | pages = 3942–7 | date = April 2003 | pmid = 12655044 | pmc = 153027 | doi = 10.1073/pnas.0736004100 | bibcode = 2003PNAS..100.3942K }}</ref>

== Regulation ==
Among the [[lipid]]-binding actin regulatory proteins, gelsolin (like [[cofilin]]) preferentially binds polyphosphoinositide (PPI).<ref name="Yu">{{cite journal | vauthors = Yu FX, Sun HQ, Janmey PA, Yin HL | title = Identification of a polyphosphoinositide-binding sequence in an actin monomer-binding domain of gelsolin | journal = The Journal of Biological Chemistry | volume = 267 | issue = 21 | pages = 14616–21 | date = July 1992 | pmid = 1321812 | doi = }}</ref> The binding sequences in gelsolin closely resemble the motifs in the other PPI-binding proteins.<ref name="Yu" />

Gelsolin's activity is stimulated by calcium ions (Ca2+).<ref name="Sun" /> Although the protein retains its overall structural integrity in both activated and deactivated states, the S6 helical tail moves like a latch depending on the concentration of calcium ions.<ref name="Burtnik">{{cite journal | vauthors = Burtnick LD, Urosev D, Irobi E, Narayan K, Robinson RC | title = Structure of the N-terminal half of gelsolin bound to actin: roles in severing, apoptosis and FAF | journal = The EMBO Journal | volume = 23 | issue = 14 | pages = 2713–22 | date = July 2004 | pmid = 15215896 | pmc = 514944 | doi = 10.1038/sj.emboj.7600280 }}</ref> The C-terminal end detects the calcium concentration within the cell. When there is no Ca2+ present, the tail of S6 shields the actin-binding sites on one of S2's helices.<ref name="Kiselar" /> When a calcium ion attaches to the S6 tail, however, it straightens, exposing the S2 actin-binding sites.<ref name="Burtnik" /> The N-terminal is directly involved in the severing of actin. S2 and S3 bind to the actin before the binding of S1 severs actin-actin bonds and caps the barbed end.<ref name="Yu" />

Gelsolin can be inhibited by a local rise in the concentration of [[phosphatidylinositol (4,5)-bisphosphate]] (PIP2), a PPI. This is a two step process. Firstly, (PIP2) binds to S2 and S3, inhibiting gelsolin from actin side binding. Then, (PIP2) binds to gelsolin’s S1, preventing gelsolin from severing actin, although (PIP2) does not bind directly to gelsolin's actin-binding site.<ref name="Yu" />

Gelsolin's severing of actin, in contrast to the severing of [[microtubules]] by [[katanin]], does not require any extra energy input.

==Cellular function==

As an important actin regulator, gelsolin plays a role in [[podosome]] formation (along with Arp3, [[cortactin]], and Rho GTPases).<ref name="Varon">{{cite journal | vauthors = Varon C, Tatin F, Moreau V, Van Obberghen-Schilling E, Fernandez-Sauze S, Reuzeau E, Kramer I, Génot E | display-authors = 6 | title = Transforming growth factor beta induces rosettes of podosomes in primary aortic endothelial cells | journal = Molecular and Cellular Biology | volume = 26 | issue = 9 | pages = 3582–94 | date = May 2006 | pmid = 16611998 | pmc = 1447430 | doi = 10.1128/MCB.26.9.3582-3594.2006 }}</ref>

Gelsolin also inhibits [[apoptosis]] by stabilizing the [[mitochondria]].<ref name="Koya" /> Prior to cell death, mitochondria normally lose [[membrane potential]] and become more permeable. Gelsolin can impede the release of [[cytochrome C]], obstructing the signal amplification that would have led to apoptosis.<ref name=pmid11039896>{{cite journal | vauthors = Kusano H, Shimizu S, Koya RC, Fujita H, Kamada S, Kuzumaki N, Tsujimoto Y | title = Human gelsolin prevents apoptosis by inhibiting apoptotic mitochondrial changes via closing VDAC | journal = Oncogene | volume = 19 | issue = 42 | pages = 4807–14 | date = October 2000 | pmid = 11039896 | doi = 10.1038/sj.onc.1203868 | doi-access = free }}</ref>

Actin can be cross-linked into a [[gel]] by actin cross-linking proteins. Gelsolin can turn this gel into a [[Sol (colloid)|sol]], hence the name gelsolin.

== Animal studies ==

Research in mice suggests that gelsolin, like other actin-severing proteins, is not expressed to a significant degree until after the early [[embryo]]nic stage—approximately 2 weeks in [[murine]] embryos.<ref name="Witke">{{cite journal | vauthors = Witke W, Sharpe AH, Hartwig JH, Azuma T, Stossel TP, Kwiatkowski DJ | title = Hemostatic, inflammatory, and fibroblast responses are blunted in mice lacking gelsolin | journal = Cell | volume = 81 | issue = 1 | pages = 41–51 | date = April 1995 | pmid = 7720072 | doi = 10.1016/0092-8674(95)90369-0 | doi-access = free }}</ref> In adult specimens, however, gelsolin is particularly important in motile cells, such as blood [[platelet]]s. Mice with null gelsolin-coding [[genes]] undergo normal [[Embryogenesis|embryonic development]], but the deformation of their blood platelets reduced their motility, resulting in a slower response to wound healing.<ref name="Witke" />

An insufficiency of gelsolin in mice has also been shown to cause increased permeability of the vascular pulmonary barrier, suggesting that gelsolin is important in the response to lung injury.<ref name="Becker">{{cite journal | vauthors = Becker PM, Kazi AA, Wadgaonkar R, Pearse DB, Kwiatkowski D, Garcia JG | title = Pulmonary vascular permeability and ischemic injury in gelsolin-deficient mice | journal = American Journal of Respiratory Cell and Molecular Biology | volume = 28 | issue = 4 | pages = 478–84 | date = April 2003 | pmid = 12654637 | doi = 10.1165/rcmb.2002-0024OC }}</ref>

== Related proteins ==

[[sequence (biology)|Sequence]] comparisons indicate an [[evolution]]ary relationship between gelsolin, villin, fragmin and severin.<ref name="pmid2850369">{{cite journal | vauthors = Way M, Weeds A | title = Nucleotide sequence of pig plasma gelsolin. Comparison of protein sequence with human gelsolin and other actin-severing proteins shows strong homologies and evidence for large internal repeats | journal = Journal of Molecular Biology | volume = 203 | issue = 4 | pages = 1127–33 | date = October 1988 | pmid = 2850369 | doi = 10.1016/0022-2836(88)90132-5 }}</ref> Six large repeating segments occur in gelsolin and villin, and 3 similar segments in severin and fragmin. While the multiple [[tandem repeat|repeat]]s have yet to be related to any known function of the actin-severing proteins, the [[Protein family|superfamily]] appears to have [[evolution|evolved]] from an ancestral [[sequence]] of 120 to 130 [[amino acid]] [[residue (chemistry)|residues]].<ref name="pmid24155256" /><ref name="pmid2850369"/>

Asgard archaea encode many functional gelsolins.<ref>{{cite journal | vauthors = Akıl C, Tran LT, Orhant-Prioux M, Baskaran Y, Manser E, Blanchoin L, Robinson RC | title = Insights into the evolution of regulated actin dynamics via characterization of primitive gelsolin/cofilin proteins from Asgard archaea | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 117 | issue = 33 | pages = 19904–19913 | date = August 2020 | pmid = 32747565 | doi = 10.1073/pnas.2009167117 | pmc = 7444086 | doi-access = free }}</ref>

== Interactions ==

Gelsolin is a [[cytoplasm|cytoplasmic]], calcium-regulated, actin-modulating [[protein]] that binds to the barbed ends of [[actin]] filaments, preventing [[monomer]] exchange (end-blocking or capping).<ref name="pmid3023087">{{cite journal | vauthors = Weeds AG, Gooch J, Pope B, Harris HE | title = Preparation and characterization of pig plasma and platelet gelsolins | journal = European Journal of Biochemistry | volume = 161 | issue = 1 | pages = 69–76 | date = November 1986 | pmid = 3023087 | doi = 10.1111/j.1432-1033.1986.tb10125.x }}</ref> It can promote nucleation (the assembly of monomers into filaments), as well as sever existing [[Protein filament|filaments]]. In addition, this protein binds with high affinity to [[fibronectin]]. [[Plasma gelsolin]] and cytoplasmic gelsolin are derived from a single [[gene]] by alternate initiation sites and differential [[splicing (genetics)|splicing]].

Gelsolin has been shown to [[Protein-protein interaction|interact]] with:
* [[Amyloid precursor protein]],<ref name="pmid10329371">{{cite journal | vauthors = Chauhan VP, Ray I, Chauhan A, Wisniewski HM | title = Binding of gelsolin, a secretory protein, to amyloid beta-protein | journal = Biochemical and Biophysical Research Communications | volume = 258 | issue = 2 | pages = 241–6 | date = May 1999 | pmid = 10329371 | doi = 10.1006/bbrc.1999.0623 }}</ref>
* [[Androgen receptor]],<ref name="pmid12941811">{{cite journal | vauthors = Nishimura K, Ting HJ, Harada Y, Tokizane T, Nonomura N, Kang HY, Chang HC, Yeh S, Miyamoto H, Shin M, Aozasa K, Okuyama A, Chang C | display-authors = 6 | title = Modulation of androgen receptor transactivation by gelsolin: a newly identified androgen receptor coregulator | journal = Cancer Research | volume = 63 | issue = 16 | pages = 4888–94 | date = August 2003 | pmid = 12941811 | doi = }}</ref>
* [[PTK2B]],<ref name="pmid12578912">{{cite journal | vauthors = Wang Q, Xie Y, Du QS, Wu XJ, Feng X, Mei L, McDonald JM, Xiong WC | display-authors = 6 | title = Regulation of the formation of osteoclastic actin rings by proline-rich tyrosine kinase 2 interacting with gelsolin | journal = The Journal of Cell Biology | volume = 160 | issue = 4 | pages = 565–75 | date = February 2003 | pmid = 12578912 | pmc = 2173747 | doi = 10.1083/jcb.200207036 }}</ref> and
* [[VDAC1]].<ref name="pmid11039896"/>

== See also ==
* [[Plasma gelsolin]]
* [[Cortactin]]
* [[Villin]]
* [[Supervillin]]
* [[Finnish type amyloidosis]]
{{clear}}

== References ==
{{reflist|30em}}

== External links ==
* {{MeshName|Gelsolin}}

{{Calcium signaling}}
{{Calcium-binding proteins}}
{{Cytoskeletal Proteins}}

{{PDB_Gallery|geneid=2934}}
* http://www.bioaegistherapeutics.com

[[Category:Proteins]]

Asgard-Archaeen

2020-08-28T09:10:16Z

131.112.112.6:

{{Automatic taxobox
| image =
| image_alt =
| image_caption =
| taxon = Asgard
| authority = [[Katarzyna Zaremba-Niedzwiedzka]], ''et al.'' 2017
| subdivision_ranks = [[Phylum|Phyla]]
| subdivision_ref =
| subdivision = *"[[Lokiarchaeota]]" [[Anja Spang|Spang]] et al. 2015
*"[[Thorarchaeota]]" [[Kiley W. Seitz|Seitz]] et al. 2016
*"[[Odinarchaeota]]" Katarzyna Zaremba-Niedzwiedzka et al. 2017
*"[[Heimdallarchaeota]]" Katarzyna Zaremba-Niedzwiedzka et al. 2017
| range_map = Global distribution of metagenomic-assembled sequences of Asgard archaea.png
| synonyms = *''Eukaryomorpha''
| synonyms_ref = <ref>{{cite journal | authors = Fournier GP, Poole AM. | year = 2018 | title = A Briefly Argued Case That Asgard Archaea Are Part of the Eukaryote Tree | journal = Front. Microbiol. | volume = 9 | pages = 1896 | doi = 10.3389/fmicb.2018.01896 | pmid = 30158917 | pmc = 6104171}}
</ref>
}}

'''Asgard''' or '''Asgardarchaeota'''<ref>Violette Da Cunha, Morgan Gaia, Daniele Gadelle, Arshan Nasir, Patrick Forterre: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5484517/ Lokiarchaea are close relatives of Euryarchaeota, not bridging the gap between prokaryotes and eukaryotes], in: PLoS Genet. 2017 Jun; 13(6): e1006810.
2017 Jun 12, [[doi: 10.1371/journal.pgen.1006810]]</ref> is a proposed [[superphylum]] consisting of a group of [[archaea]] that includes [[Lokiarchaeota]], [[Thorarchaeota]], [[Odinarchaeota]], and [[Heimdallarchaeota]].<ref name="Zaremba">{{Cite journal|last=Zaremba-Niedzwiedzka|first=Katarzyna|last2=Caceres|first2=Eva F.|last3=Saw|first3=Jimmy H.|last4=Bäckström|first4=Disa|last5=Juzokaite|first5=Lina|last6=Vancaester|first6=Emmelien|last7=Seitz|first7=Kiley W.|last8=Anantharaman|first8=Karthik|last9=Starnawski|first9=Piotr|date=11 January 2017|title=Asgard archaea illuminate the origin of eukaryotic cellular complexity|journal=Nature|language=En|volume=541|issue=7637|pages=353–358|doi=10.1038/nature21031|pmid=28077874|issn=1476-4687|bibcode=2017Natur.541..353Z|url=https://escholarship.org/content/qt0qh5400s/qt0qh5400s.pdf?t=pgp8bj}}</ref> A representative of the group was cultivated.<ref name=":0">{{Cite journal|last=Imachi|first=Hiroyuki|last2=Nobu|first2=Masaru K.|last3=Nakahara|first3=Nozomi|last4=Morono|first4=Yuki|last5=Ogawara|first5=Miyuki|last6=Takaki|first6=Yoshihiro|last7=Takano|first7=Yoshinori|last8=Uematsu|first8=Katsuyuki|last9=Ikuta|first9=Tetsuro|last10=Ito|first10=Motoo|last11=Matsui|first11=Yohei|date=2020-01-23|title=Isolation of an archaeon at the prokaryote–eukaryote interface|journal=Nature|language=en|volume=577|issue=7791|pages=519–525|doi=10.1038/s41586-019-1916-6|pmid=31942073|pmc=7015854|bibcode=2020Natur.577..519I|issn=1476-4687}}</ref> The Asgard superphylum represents the closest [[Prokaryote|prokaryotic]] relatives of [[eukaryote]]s<ref name="Eme">{{Cite journal|last=Eme|first=Laura|last2=Spang|first2=Anja|last3=Lombard|first3=Jonathan|last4=Stairs|first4=Courtney W.|last5=Ettema|first5=Thijs J. G.|date=10 November 2017|title=Archaea and the origin of eukaryotes|journal=Nature Reviews Microbiology|language=En|volume=15|issue=12|pages=711–723|doi=10.1038/nrmicro.2017.133|pmid=29123225|issn=1740-1534|url=https://zenodo.org/record/3451113}}</ref>, which possibly emerged from an ancestral lineage of Asgardarchaeota after assimilating bacteria through the process of [[symbiogenesis]]<ref name="Eme"/><ref>{{Cite journal|last=Williams|first=Tom A.|last2=Cox|first2=Cymon J.|last3=Foster|first3=Peter G.|last4=Szöllősi|first4=Gergely J.|last5=Embley|first5=T. Martin|date=2019-12-09|title=Phylogenomics provides robust support for a two-domains tree of life|journal=Nature Ecology & Evolution|language=en|volume=4|issue=1|pages=138–147|doi=10.1038/s41559-019-1040-x|issn=2397-334X|pmc=6942926|pmid=31819234}}</ref>.

== Discovery ==
In the summer of 2010, sediments from a gravity [[Core sample|core]] taken in the rift valley on the Knipovich ridge in the Arctic Ocean, near the so-called [[Loki's Castle]] [[hydrothermal vent]] site, were analysed. Specific sediment horizons previously shown to contain high abundances of novel archaeal lineages, were subjected to [[Metagenomics|metagenomic analysis]].<ref>{{cite journal |last1=Jørgensen |first1=Steffen Leth |last2=Hannisdal |first2=Bjarte |last3=Lanzen |first3=Anders |last4=Baumberger |first4=Tamara |last5=Flesland |first5=Kristin |last6=Fonseca |first6=Rita |last7=Øvreås |first7=Lise |last8=Steen |first8=Ida H |last9=Thorseth |first9=Ingunn H |last10=Pedersen |first10=Rolf B |last11=Schleper |first11=Christa |title=Correlating microbial community profiles with geochemical data in highly stratified sediments from the Arctic Mid-Ocean Ridge |journal=PNAS |date=September 5, 2012 |volume=109 |issue=42 |pages=E2846–55 |doi=10.1073/pnas.1207574109 |pmid=23027979 |pmc=3479504}}</ref><ref>{{cite journal |last1=Jørgensen |first1=Steffen Leth |last2=Thorseth |first2=Ingunn H |last3=Pedersen |first3=Rolf B |last4=Baumberger |first4=Tamara |last5=Schleper |first5=Christa |title=Quantitative and phylogenetic study of the Deep Sea Archaeal Group in sediments of the Arctic mid-ocean spreading ridge |journal=Frontiers in Microbiology |date=October 4, 2013 |doi=10.3389/fmicb.2013.00299 |pmid=24109477 |pmc=3790079 |volume=4|pages=299 }}</ref>

In 2015, an [[Uppsala University]]-led team proposed the ''[[Lokiarchaeota]]'' phylum based on [[phylogenetic]] analyses using a set of [[Highly conserved sequence|highly conserved]] protein-coding genes.<ref name="SpangSaw2015">{{Cite journal|last=Spang|first=Anja|last2=Saw|first2=Jimmy H.|last3=Jørgensen|first3=Steffen L.|last4=Zaremba-Niedzwiedzka|first4=Katarzyna|last5=Martijn|first5=Joran|last6=Lind|first6=Anders E.|last7=Eijk|first7=Roel van|last8=Schleper|first8=Christa|last9=Guy|first9=Lionel|date=May 2015|title=Complex archaea that bridge the gap between prokaryotes and eukaryotes|journal=Nature|language=En|volume=521|issue=7551|pages=173–179|doi=10.1038/nature14447|pmid=25945739|issn=1476-4687|pmc=4444528|bibcode=2015Natur.521..173S}}</ref> Through a reference to the hydrothermal vent complex from which the first genome sample originated, the name refers to [[Loki]], the Norse shape-shifting god.<ref name="Yong">{{Cite news|url=https://www.theatlantic.com/science/archive/2017/01/our-origins-in-asgard/512645/|title=Break in the Search for the Origin of Complex Life|last=Yong|first=Ed|work=The Atlantic|access-date=2018-03-21|language=en-US}}</ref> The Loki of mythology has been described as "a staggeringly complex, confusing, and ambivalent figure who has been the catalyst of countless unresolved scholarly controversies",<ref>{{cite journal |last1=von Schnurbein |first1=Stefanie |title=The Function of Loki in Snorri Sturluson's "Edda" |journal=History of Religions |date=November 2000 |volume=40 |issue=2 |pages=109–124 |doi=10.1086/463618}}</ref> analogous to the role of Lokiarchaeota in the debates about the origin of eukaryotes.<ref name="SpangSaw2015"/><ref>{{cite journal |last1=Spang |first1=Anja |last2=Eme |first2=Laura |last3=Saw |first3=Jimmy H. |last4=Caceres |first4=Eva F. |last5=Zaremba-Niedzwiedzka |first5=Katarzyna |last6=Lombard |first6=Jonathan |last7=Guy |first7=Lionel |last8=Ettema |first8=Thijs J. G. |last9=Rokas |first9=Antonis |title=Asgard archaea are the closest prokaryotic relatives of eukaryotes |journal=PLOS Genetics |date=29 March 2018 |volume=14 |issue=3 |pages=e1007080 |doi=10.1371/journal.pgen.1007080|pmid=29596421 |pmc=5875740 }}</ref>

In 2016, a [[University of Texas at Austin|University of Texas]]-led team discovered ''[[Thorarchaeota]]'' from samples taken from the [[White Oak River]] in North Carolina, named in reference to [[Thor]], another Norse god.<ref>{{Cite journal|last=Seitz|first=Kiley W|last2=Lazar|first2=Cassandre S|last3=Hinrichs|first3=Kai-Uwe|last4=Teske|first4=Andreas P|last5=Baker|first5=Brett J|date=29 January 2016|title=Genomic reconstruction of a novel, deeply branched sediment archaeal phylum with pathways for acetogenesis and sulfur reduction|journal=The ISME Journal|language=En|volume=10|issue=7|pages=1696–1705|doi=10.1038/ismej.2015.233|pmid=26824177|pmc=4918440|issn=1751-7370}}</ref>

Additional samples from Loki's Castle, [[Yellowstone National Park]], [[Bay of Aarhus|Aarhus Bay]], an aquifer near the [[Colorado River]], New Zealand's [[Radiata Pool]], hydrothermal vents near [[Taketomi Island]], Japan, and the [[White Oak River]] estuary in the United States led researchers to discover ''[[Odinarchaeota]]'' and ''[[Heimdallarchaeota]]'',<ref name="Zaremba"/> and following the naming convention having been established to use Norse deities, the archaea were named for [[Odin]] and [[Heimdallr]], respectively. Researchers therefore, named the superphylum containing these microbes “[[Asgard]]”, after the realm of the deities in Norse mythology.<ref name="Zaremba"/>

In January 2020, scientists reported that ''[[Candidatus Prometheoarchaeum syntrophicum]]'', a member of Lokiarcheota, may be a possible link between the simple [[prokaryotic]] microorganisms and the complex [[eukaryotic]] microorganisms occurring approximately two billion years ago.<ref name="NYT-2020115">{{cite news |last=Zimmer |first=Carl |title=This Strange Microbe May Mark One of Life's Great Leaps - A organism living in ocean muck offers clues to the origins of the complex cells of all animals and plants. |url=https://www.nytimes.com/2020/01/15/science/cells-eukaryotes-archaea.html |date=15 January 2020 |work=[[The New York Times]] |accessdate=16 January 2020 }}</ref><ref name=":0" />

== Description ==
{{Expand section|date=September 2019}}

Asgard members encode many eukaryotic signature proteins, including novel GTPases, membrane-remodelling proteins like [[ESCRT]] and [[CHMP4B|SNF7]], a [[ubiquitin]] modifier system, and N-[[glycosylation]] pathway homologs.<ref name="Zaremba"/>

Asgard archaeons have a regulated [[actin]] [[cytoskeleton]], and the [[profilin]]s and [[gelsolin]]s they use can interact with eukaryotic actins.<ref>{{cite journal |last1=Akıl |first1=Caner |last2=Robinson |first2=Robert C. |title=Genomes of Asgard archaea encode profilins that regulate actin |journal=Nature |date=3 October 2018 |volume=562 |issue=7727 |pages=439–443 |doi=10.1038/s41586-018-0548-6|pmid=30283132 |bibcode=2018Natur.562..439A }}</ref> <ref>{{cite biorxiv |last1=Akıl |first1=Caner |last2=Tran |first2=Linh T. |last3= Orhant-Prioux |first3=Magali |last4=Baskaran |first4=Yohendran |last5=Manser |first5=Edward |last6=Blanchoin |first6=Laurent |last7=Robinson |first7=Robert C. |title=Complex eukaryotic-like actin regulation systems from Asgard archaea |date=14 September 2019 | |biorxiv=10.1101/768580}}</ref> <ref>{{cite journal |last1=Akıl |first1=Caner |last2=Tran |first2=Linh T. |last3= Orhant-Prioux |first3=Magali |last4=Baskaran |first4=Yohendran |last5=Manser |first5=Edward |last6=Blanchoin |first6=Laurent |last7=Robinson |first7=Robert C. |title=Insights into the evolution of regulated actin dynamics via characterization of primitive gelsolin/cofilin proteins from Asgard archaea |journal=PNAS |date=18 August 2020 |volume=117 |issue=33 |pages=19904-19913 |doi=10.1073/pnas.2009167117|pmid=32747565}}</ref> They also seem to form vesicles under [[cryoEM]]. Some may have a [[PKD domain]] [[S-layer]].<ref name=":0" />

===Metabolism===
<gallery mode="packed" heights="180" style="font-size:100%; line-height:130%">
Asgard archaea Phyla.png|Metabolic pathways of Asgard archaea, variation by Phyla<ref name="kindler2019"/>
Asgard archaea in various environments.png|Metabolic pathways of Asgard archaea, variation by environment<ref name="kindler2019"/>
</gallery>

Asgard archaea are [[obligate anaerobe]]s. They have a [[Wood–Ljungdahl pathway]] and perform [[glycolysis]]. Members can be [[autotroph]]s, [[ heterotroph]]s, or [[phototroph]]s using [[heliorhodopsin]].<ref name="kindler2019">{{Cite journal |last=MacLeod |first=Fraser |last2=Kindler |first2=Gareth S. |last3=Wong |first3=Hon Lun |last4=Chen |first4=Ray |last5=Burns |first5=Brendan P. |date=2019 |title=Asgard archaea: Diversity, function, and evolutionary implications in a range of microbiomes |journal=AIMS Microbiology |volume=5 |issue=1 |pages=48–61 |doi=10.3934/microbiol.2019.1.48 |issn=2471-1888 |pmc=6646929 |pmid=31384702}}</ref> One member, Candidatus ''Prometheoarchaeum syntrophicum'', performs [[syntrophy]] with a sulfur-reducing proteobacteria and a [[methanogenic]] archaea.<ref name=":0" />

The [[RuBisCO]] they have are not carbon-fixing, but likely used for nucleoside salvaging.<ref name="kindler2019"/>

== Classification ==
The phylogenetic relationship of this group is still under discussion. The relationship of the members is approximately as follows:<ref name="Eme"/><ref>{{Cite journal|last=Williams|first=Tom A.|last2=Cox|first2=Cymon J.|last3=Foster|first3=Peter G.|last4=Szöllősi|first4=Gergely J.|last5=Embley|first5=T. Martin|date=2019-12-09|title=Phylogenomics provides robust support for a two-domains tree of life|journal=Nature Ecology & Evolution|language=en|volume=4|issue=1|pages=138–147|doi=10.1038/s41559-019-1040-x|issn=2397-334X|pmc=6942926|pmid=31819234}}</ref>

{{Clade
|label1=[[Proteoarchaeota]]
|style=font-size:80%; line-height:80%+
|1={{Clade
| label1=[[TACK]]
| 1={{Clade
| 1=[[Korarchaeota]]
| 2={{Clade
| 1=[[Crenarchaeota]]
| 2={{Clade
| 1={{Clade |1=[[Aigarchaeota]]|2=[[Geoarchaeota]]}}
| 2={{Clade |1=[[Thaumarchaeota]] |2=[[Bathyarchaeota]]}} }} }} }}
| label2=Asgard
| 2={{Clade
| 1={{Clade |1=[[Lokiarchaeota]] |2=[[Odinarchaeota]] |3=[[Thorarchaeota]]}}
| 2={{Clade |1=[[Heimdallarchaeota]]
| label2=(+[[Alphaproteobacteria|α─Proteobacteria]])
|2=[[Eukaryota]] }} }} }}
}}
The Heimdallarchaeota are considered the deepest branching Asgard archaea.<ref name=":0" /> The Eukaryotes may be sister to the Heimdallarchaeota or the Asgard archaea. A favored scenario is syntrophy, where one organism depends on the feeding of the other. In this case, the syntrophy may have been due to the Asgard archaea having been incorporated in an unknown type of bacteria, developing into the nucleus. An α-proteobacterium was incorporated to become the mitochondrion.<ref>{{Cite journal|last=López-García|first=Purificación|last2=Moreira|first2=David|date=2019-07-01|title=Eukaryogenesis, a syntrophy affair|journal=Nature Microbiology|language=en|volume=4|issue=7|pages=1068–1070|doi=10.1038/s41564-019-0495-5|issn=2058-5276|pmc=6684364|pmid=31222170}}</ref>

==References==
{{Reflist}}

==External links==
* Traci Watson: [https://www.nature.com/articles/d41586-019-01496-w#ref-CR7 The trickster microbes that are shaking up the tree of life], in: [[Nature (journal)|Nature]], 14 May 2019

{{Archaea classification|state=collapsed}}
{{Taxonbar|from=Q45003302}}

[[Category:Archaea]]
[[Category:Superphyla]]