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| | ==Crystal Structure of the MDA5 Helicase Insert Domain== | | ==Crystal Structure of the MDA5 Helicase Insert Domain== |
| - | <StructureSection load='3ts9' size='340' side='right' caption='[[3ts9]], [[Resolution|resolution]] 2.00Å' scene=''> | + | <StructureSection load='3ts9' size='340' side='right'caption='[[3ts9]], [[Resolution|resolution]] 2.00Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[3ts9]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3TS9 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3TS9 FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[3ts9]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3TS9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3TS9 FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.003Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">Ifih1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=10090 Mus musculus])</td></tr>
| + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> |
| - | <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> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3ts9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ts9 OCA], [https://pdbe.org/3ts9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3ts9 RCSB], [https://www.ebi.ac.uk/pdbsum/3ts9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3ts9 ProSAT]</span></td></tr> |
| - | <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=3ts9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ts9 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3ts9 RCSB], [http://www.ebi.ac.uk/pdbsum/3ts9 PDBsum]</span></td></tr> | + | |
| | </table> | | </table> |
| - | <div style="background-color:#fffaf0;">
| + | == Function == |
| - | == Publication Abstract from PubMed == | + | [https://www.uniprot.org/uniprot/IFIH1_MOUSE IFIH1_MOUSE] 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 mRNA lacking 2'-O-methylation at their 5' cap and long-dsRNA (>1 kb in length). 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. Responsible for detecting the Picornaviridae family members such as encephalomyocarditis virus (EMCV), mengo encephalomyocarditis virus (ENMG), and theiler's murine encephalomyelitis virus (TMEV). Can also detect other viruses such as dengue virus (DENV), west Nile virus (WNV), and reovirus. Also involved in antiviral signaling in response to viruses containing a dsDNA genome, such as vaccinia virus. Plays an important role in amplifying innate immune signaling through recognition of RNA metabolites that are produced during virus infection by ribonuclease L (RNase L). May play an important role in enhancing natural killer cell function and may be involved in growth inhibition and apoptosis in several tumor cell lines.<ref>PMID:12015121</ref> <ref>PMID:16625202</ref> <ref>PMID:17942531</ref> <ref>PMID:19656871</ref> <ref>PMID:21217758</ref> |
| - | Melanoma differentiation-associated gene-5 (MDA5) detects viral double-stranded RNA in the cytoplasm. RNA binding induces MDA5 to activate the signalling adaptor MAVS through interactions between the caspase recruitment domains (CARDs) of the two proteins. The molecular mechanism of MDA5 signalling is not well understood. Here, we show that MDA5 cooperatively binds short RNA ligands as a dimer with a 16-18-basepair footprint. A crystal structure of the MDA5 helicase-insert domain demonstrates an evolutionary relationship with the archaeal Hef helicases. In X-ray solution structures, the CARDs in unliganded MDA5 are flexible, and RNA binds on one side of an asymmetric MDA5 dimer, bridging the two subunits. On longer RNA, full-length and CARD-deleted MDA5 constructs assemble into ATP-sensitive filaments. We propose a signalling model in which the CARDs on MDA5-RNA filaments nucleate the assembly of MAVS filaments with the same polymeric geometry.
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| - | | + | |
| - | MDA5 cooperatively forms dimers and ATP-sensitive filaments upon binding double-stranded RNA.,Berke IC, Modis Y EMBO J. 2012 Feb 7. doi: 10.1038/emboj.2012.19. PMID:22314235<ref>PMID:22314235</ref>
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| - | | + | |
| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
| + | |
| - | </div> | + | |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| | + | [[Category: Large Structures]] |
| | [[Category: Mus musculus]] | | [[Category: Mus musculus]] |
| - | [[Category: RNA helicase]]
| + | [[Category: Berke IC]] |
| - | [[Category: Berke, I C]] | + | [[Category: Modis Y]] |
| - | [[Category: Modis, Y]] | + | |
| - | [[Category: Antiviral protein]]
| + | |
| - | [[Category: Dexd/h helicase]]
| + | |
| - | [[Category: Fancm helicase]]
| + | |
| - | [[Category: Helix bundle]]
| + | |
| - | [[Category: Hydrolase]]
| + | |
| - | [[Category: Rig-i-like helicase]]
| + | |
| - | [[Category: Sf2 helicase]]
| + | |
| - | [[Category: Super family 2 helicase]]
| + | |
| Structural highlights
Function
IFIH1_MOUSE 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 mRNA lacking 2'-O-methylation at their 5' cap and long-dsRNA (>1 kb in length). 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. Responsible for detecting the Picornaviridae family members such as encephalomyocarditis virus (EMCV), mengo encephalomyocarditis virus (ENMG), and theiler's murine encephalomyelitis virus (TMEV). Can also detect other viruses such as dengue virus (DENV), west Nile virus (WNV), and reovirus. Also involved in antiviral signaling in response to viruses containing a dsDNA genome, such as vaccinia virus. Plays an important role in amplifying innate immune signaling through recognition of RNA metabolites that are produced during virus infection by ribonuclease L (RNase L). May play an important role in enhancing natural killer cell function and may be involved in growth inhibition and apoptosis in several tumor cell lines.[1] [2] [3] [4] [5]
References
- ↑ Kovacsovics M, Martinon F, Micheau O, Bodmer JL, Hofmann K, Tschopp J. Overexpression of Helicard, a CARD-containing helicase cleaved during apoptosis, accelerates DNA degradation. Curr Biol. 2002 May 14;12(10):838-43. PMID:12015121
- ↑ Kato H, Takeuchi O, Sato S, Yoneyama M, Yamamoto M, Matsui K, Uematsu S, Jung A, Kawai T, Ishii KJ, Yamaguchi O, Otsu K, Tsujimura T, Koh CS, Reis e Sousa C, Matsuura Y, Fujita T, Akira S. Differential roles of MDA5 and RIG-I helicases in the recognition of RNA viruses. Nature. 2006 May 4;441(7089):101-5. Epub 2006 Apr 9. PMID:16625202 doi:http://dx.doi.org/nature04734
- ↑ Loo YM, Fornek J, Crochet N, Bajwa G, Perwitasari O, Martinez-Sobrido L, Akira S, Gill MA, Garcia-Sastre A, Katze MG, Gale M Jr. Distinct RIG-I and MDA5 signaling by RNA viruses in innate immunity. J Virol. 2008 Jan;82(1):335-45. Epub 2007 Oct 17. PMID:17942531 doi:http://dx.doi.org/10.1128/JVI.01080-07
- ↑ Pichlmair A, Schulz O, Tan CP, Rehwinkel J, Kato H, Takeuchi O, Akira S, Way M, Schiavo G, Reis e Sousa C. Activation of MDA5 requires higher-order RNA structures generated during virus infection. J Virol. 2009 Oct;83(20):10761-9. doi: 10.1128/JVI.00770-09. Epub 2009 Aug 5. PMID:19656871 doi:10.1128/JVI.00770-09
- ↑ Zust R, Cervantes-Barragan L, Habjan M, Maier R, Neuman BW, Ziebuhr J, Szretter KJ, Baker SC, Barchet W, Diamond MS, Siddell SG, Ludewig B, Thiel V. Ribose 2'-O-methylation provides a molecular signature for the distinction of self and non-self mRNA dependent on the RNA sensor Mda5. Nat Immunol. 2011 Feb;12(2):137-43. doi: 10.1038/ni.1979. Epub 2011 Jan 9. PMID:21217758 doi:10.1038/ni.1979
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