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4nqk

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==Structure of an Ubiquitin complex==
==Structure of an Ubiquitin complex==
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<StructureSection load='4nqk' size='340' side='right' caption='[[4nqk]], [[Resolution|resolution]] 3.70&Aring;' scene=''>
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<StructureSection load='4nqk' size='340' side='right'caption='[[4nqk]], [[Resolution|resolution]] 3.70&Aring;' scene=''>
== Structural highlights ==
== Structural highlights ==
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<table><tr><td colspan='2'>[[4nqk]] is a 10 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4NQK OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4NQK FirstGlance]. <br>
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<table><tr><td colspan='2'>[[4nqk]] is a 10 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4NQK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4NQK FirstGlance]. <br>
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</td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">DDX58 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN]), UBC ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.7&#8491;</td></tr>
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<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/RNA_helicase RNA helicase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.6.4.13 3.6.4.13] </span></td></tr>
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4nqk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4nqk OCA], [https://pdbe.org/4nqk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4nqk RCSB], [https://www.ebi.ac.uk/pdbsum/4nqk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4nqk ProSAT]</span></td></tr>
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4nqk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4nqk OCA], [http://pdbe.org/4nqk PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4nqk RCSB], [http://www.ebi.ac.uk/pdbsum/4nqk PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4nqk ProSAT]</span></td></tr>
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</table>
</table>
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== Disease ==
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[https://www.uniprot.org/uniprot/RIGI_HUMAN RIGI_HUMAN] Singleton-Merten dysplasia. The disease is caused by variants affecting the gene represented in this entry.
== Function ==
== Function ==
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[[http://www.uniprot.org/uniprot/DDX58_HUMAN DDX58_HUMAN]] Innate immune receptor which acts as a cytoplasmic sensor of viral nucleic acids and plays a major role in sensing viral infection and in the activation of a cascade of antiviral responses including the induction of type I interferons and proinflammatory cytokines. Its ligands include: 5'-triphosphorylated ssRNA and dsRNA and short dsRNA (<1 kb in length). In addition to the 5'-triphosphate moiety, blunt-end base pairing at the 5'-end of the RNA is very essential. Overhangs at the non-triphosphorylated end of the dsRNA RNA have no major impact on its activity. A 3'overhang at the 5'triphosphate end decreases and any 5'overhang at the 5' triphosphate end abolishes its activity. Upon ligand binding it associates with mitochondria antiviral signaling protein (MAVS/IPS1) which activates the IKK-related kinases: TBK1 and IKBKE which phosphorylate interferon regulatory factors: IRF3 and IRF7 which in turn activate transcription of antiviral immunological genes, including interferons (IFNs); IFN-alpha and IFN-beta. Detects both positive and negative strand RNA viruses including members of the families Paramyxoviridae: Human respiratory syncytial virus and measles virus (MeV), Rhabdoviridae: vesicular stomatitis virus (VSV), Orthomyxoviridae: influenza A and B virus, Flaviviridae: Japanese encephalitis virus (JEV), hepatitis C virus (HCV), dengue virus (DENV) and west Nile virus (WNV). It also detects rotavirus and reovirus. Also involved in antiviral signaling in response to viruses containing a dsDNA genome such as Epstein-Barr virus (EBV). Detects dsRNA produced from non-self dsDNA by RNA polymerase III, such as Epstein-Barr virus-encoded RNAs (EBERs). May play important roles in granulocyte production and differentiation, bacterial phagocytosis and in the regulation of cell migration.<ref>PMID:15208624</ref> <ref>PMID:16125763</ref> <ref>PMID:15708988</ref> <ref>PMID:16153868</ref> <ref>PMID:16127453</ref> <ref>PMID:17190814</ref> <ref>PMID:18636086</ref> <ref>PMID:19631370</ref> <ref>PMID:19576794</ref> <ref>PMID:19122199</ref> <ref>PMID:19211564</ref> <ref>PMID:19609254</ref> <ref>PMID:21742966</ref> [[http://www.uniprot.org/uniprot/UBC_HUMAN UBC_HUMAN]] Ubiquitin exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, DNA-damage responses as well as in signaling processes leading to activation of the transcription factor NF-kappa-B. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling.<ref>PMID:16543144</ref> <ref>PMID:19754430</ref>
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[https://www.uniprot.org/uniprot/RIGI_HUMAN RIGI_HUMAN] Innate immune receptor that senses cytoplasmic viral nucleic acids and activates a downstream signaling cascade leading to the production of type I interferons and pro-inflammatory cytokines (PubMed:15208624, PubMed:16125763, PubMed:15708988, PubMed:16127453, PubMed:16153868, PubMed:17190814, PubMed:18636086, PubMed:19122199, PubMed:19211564, PubMed:29117565, PubMed:28469175, PubMed:31006531, PubMed:34935440). Forms a ribonucleoprotein complex with viral RNAs on which it homooligomerizes to form filaments (PubMed:15208624, PubMed:15708988). The homooligomerization allows the recruitment of RNF135 an E3 ubiquitin-protein ligase that activates and amplifies the RIG-I-mediated antiviral signaling in an RNA length-dependent manner through ubiquitination-dependent and -independent mechanisms (PubMed:28469175, PubMed:31006531). Upon activation, associates with mitochondria antiviral signaling protein (MAVS/IPS1) that activates the IKK-related kinases TBK1 and IKBKE which in turn phosphorylate the interferon regulatory factors IRF3 and IRF7, activating transcription of antiviral immunological genes including the IFN-alpha and IFN-beta interferons (PubMed:28469175, PubMed:31006531). Ligands include 5'-triphosphorylated ssRNAs and dsRNAs but also short dsRNAs (<1 kb in length) (PubMed:15208624, PubMed:15708988, PubMed:19576794, PubMed:19609254, PubMed:21742966). In addition to the 5'-triphosphate moiety, blunt-end base pairing at the 5'-end of the RNA is very essential (PubMed:15208624, PubMed:15708988, PubMed:19576794, PubMed:19609254, PubMed:21742966). Overhangs at the non-triphosphorylated end of the dsRNA RNA have no major impact on its activity (PubMed:15208624, PubMed:15708988, PubMed:19576794, PubMed:19609254, PubMed:21742966). A 3'overhang at the 5'triphosphate end decreases and any 5'overhang at the 5' triphosphate end abolishes its activity (PubMed:15208624, PubMed:15708988, PubMed:19576794, PubMed:19609254, PubMed:21742966). Detects both positive and negative strand RNA viruses including members of the families Paramyxoviridae: Human respiratory syncytial virus and measles virus (MeV), Rhabdoviridae: vesicular stomatitis virus (VSV), Orthomyxoviridae: influenza A and B virus, Flaviviridae: Japanese encephalitis virus (JEV), hepatitis C virus (HCV), dengue virus (DENV) and west Nile virus (WNV) (PubMed:21616437, PubMed:21884169). It also detects rotaviruses and reoviruses (PubMed:21616437, PubMed:21884169). Detects and binds to SARS-CoV-2 RNAs which is inhibited by m6A RNA modifications (Ref.66). Also involved in antiviral signaling in response to viruses containing a dsDNA genome such as Epstein-Barr virus (EBV) (PubMed:19631370). Detects dsRNA produced from non-self dsDNA by RNA polymerase III, such as Epstein-Barr virus-encoded RNAs (EBERs). May play important roles in granulocyte production and differentiation, bacterial phagocytosis and in the regulation of cell migration.<ref>PMID:15208624</ref> <ref>PMID:15708988</ref> <ref>PMID:16125763</ref> <ref>PMID:16127453</ref> <ref>PMID:16153868</ref> <ref>PMID:17190814</ref> <ref>PMID:18636086</ref> <ref>PMID:19122199</ref> <ref>PMID:19211564</ref> <ref>PMID:19576794</ref> <ref>PMID:19609254</ref> <ref>PMID:19631370</ref> <ref>PMID:21742966</ref> <ref>PMID:28469175</ref> <ref>PMID:29117565</ref> <ref>PMID:31006531</ref> <ref>PMID:34935440</ref> <ref>PMID:17974005</ref> <ref>PMID:21616437</ref> <ref>PMID:21884169</ref>
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<div style="background-color:#fffaf0;">
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== Publication Abstract from PubMed ==
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Ubiquitin (Ub) has important roles in a wide range of intracellular signalling pathways. In the conventional view, ubiquitin alters the signalling activity of the target protein through covalent modification, but accumulating evidence points to the emerging role of non-covalent interaction between ubiquitin and the target. In the innate immune signalling pathway of a viral RNA sensor, RIG-I, both covalent and non-covalent interactions with K63-linked ubiquitin chains (K63-Ubn) were shown to occur in its signalling domain, a tandem caspase activation and recruitment domain (hereafter referred to as 2CARD). Non-covalent binding of K63-Ubn to 2CARD induces its tetramer formation, a requirement for downstream signal activation. Here we report the crystal structure of the tetramer of human RIG-I 2CARD bound by three chains of K63-Ub2. 2CARD assembles into a helical tetramer resembling a 'lock-washer', in which the tetrameric surface serves as a signalling platform for recruitment and activation of the downstream signalling molecule, MAVS. Ubiquitin chains are bound along the outer rim of the helical trajectory, bridging adjacent subunits of 2CARD and stabilizing the 2CARD tetramer. The combination of structural and functional analyses reveals that binding avidity dictates the K63-linkage and chain-length specificity of 2CARD, and that covalent ubiquitin conjugation of 2CARD further stabilizes the Ub-2CARD interaction and thus the 2CARD tetramer. Our work provides unique insights into the novel types of ubiquitin-mediated signal-activation mechanism, and previously unexpected synergism between the covalent and non-covalent ubiquitin interaction modes.
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Structural basis for ubiquitin-mediated antiviral signal activation by RIG-I.,Peisley A, Wu B, Xu H, Chen ZJ, Hur S Nature. 2014 May 1;509(7498):110-4. doi: 10.1038/nature13140. Epub 2014 Mar 2. PMID:24590070<ref>PMID:24590070</ref>
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From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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</div>
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<div class="pdbe-citations 4nqk" style="background-color:#fffaf0;"></div>
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== References ==
== References ==
<references/>
<references/>
__TOC__
__TOC__
</StructureSection>
</StructureSection>
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[[Category: Human]]
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[[Category: Homo sapiens]]
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[[Category: RNA helicase]]
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[[Category: Large Structures]]
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[[Category: Hur, S]]
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[[Category: Hur S]]
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[[Category: Peisley, A]]
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[[Category: Peisley A]]
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[[Category: Wu, B]]
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[[Category: Wu B]]
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[[Category: Card domain]]
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[[Category: Hydrolase-apoptosis complex]]
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Current revision

Structure of an Ubiquitin complex

PDB ID 4nqk

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