View source for 8dxq


==Structure of LRRC8C-LRRC8A(IL125) Chimera, Class 4==
<StructureSection load='8dxq' size='340' side='right'caption='[[8dxq]], [[Resolution|resolution]] 3.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8dxq]] is a 7 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=8DXQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8DXQ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.8&#8491;</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=8dxq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8dxq OCA], [https://pdbe.org/8dxq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8dxq RCSB], [https://www.ebi.ac.uk/pdbsum/8dxq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8dxq ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/LRC8A_HUMAN LRC8A_HUMAN] Autosomal agammaglobulinemia. The disease is caused by mutations affecting the gene represented in this entry. A chromosomal aberration involving LRRC8 has been found in a patient with congenital agammaglobulinemia. Translocation t(9;20)(q33.2;q12). The translocation truncates the LRRC8 gene, resulting in deletion of the eighth, ninth, and half of the seventh LRR domains.
== Function ==
[https://www.uniprot.org/uniprot/LRC8C_HUMAN LRC8C_HUMAN] Non-essential component of the volume-regulated anion channel (VRAC, also named VSOAC channel), an anion channel required to maintain a constant cell volume in response to extracellular or intracellular osmotic changes (PubMed:24790029, PubMed:26824658, PubMed:28193731). The VRAC channel conducts iodide better than chloride and can also conduct organic osmolytes like taurine (PubMed:24790029, PubMed:26824658, PubMed:28193731). Plays a redundant role in the efflux of amino acids, such as aspartate and glutamate, in response to osmotic stress (PubMed:24790029, PubMed:26824658, PubMed:28193731). The VRAC channel also mediates transport of immunoreactive cyclic dinucleotide GMP-AMP (2'-3'-cGAMP), an immune messenger produced in response to DNA virus in the cytosol (PubMed:33171122). Channel activity requires LRRC8A plus at least one other family member (LRRC8B, LRRC8C, LRRC8D or LRRC8E); channel characteristics depend on the precise subunit composition (PubMed:24790029, PubMed:26824658, PubMed:28193731).<ref>PMID:24790029</ref> <ref>PMID:26824658</ref> <ref>PMID:28193731</ref> <ref>PMID:33171122</ref> [https://www.uniprot.org/uniprot/LRC8A_HUMAN LRC8A_HUMAN] Essential component of the volume-regulated anion channel (VRAC, also named VSOAC channel), an anion channel required to maintain a constant cell volume in response to extracellular or intracellular osmotic changes (PubMed:24725410, PubMed:24790029, PubMed:26530471, PubMed:26824658, PubMed:28193731, PubMed:29769723). The VRAC channel conducts iodide better than chloride and can also conduct organic osmolytes like taurine (PubMed:24725410, PubMed:24790029, PubMed:26530471, PubMed:26824658, PubMed:28193731). Mediates efflux of amino acids, such as aspartate and glutamate, in response to osmotic stress (PubMed:28193731). LRRC8A and LRRC8D are required for the uptake of the drug cisplatin (PubMed:26530471). Required for in vivo channel activity, together with at least one other family member (LRRC8B, LRRC8C, LRRC8D or LRRC8E); channel characteristics depend on the precise subunit composition (PubMed:24790029, PubMed:26824658, PubMed:28193731). Can form functional channels by itself (in vitro) (PubMed:26824658). Involved in B-cell development: required for the pro-B cell to pre-B cell transition (PubMed:14660746). Also required for T-cell development (By similarity).[UniProtKB:Q80WG5]<ref>PMID:14660746</ref> <ref>PMID:24725410</ref> <ref>PMID:24790029</ref> <ref>PMID:26530471</ref> <ref>PMID:26824658</ref> <ref>PMID:28193731</ref> <ref>PMID:29769723</ref> 
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== Publication Abstract from PubMed ==
Volume-regulated anion channels (VRACs) mediate volume regulatory Cl(-) and organic solute efflux from vertebrate cells. VRACs are heteromeric assemblies of LRRC8A-E proteins with unknown stoichiometries. Homomeric LRRC8A and LRRC8D channels have a small pore, hexameric structure. However, these channels are either non-functional or exhibit abnormal regulation and pharmacology, limiting their utility for structure-function analyses. We circumvented these limitations by developing novel homomeric LRRC8 chimeric channels with functional properties consistent with those of native VRAC/LRRC8 channels. We demonstrate here that the LRRC8C-LRRC8A(IL1(25)) chimera comprising LRRC8C and 25 amino acids unique to the first intracellular loop (IL1) of LRRC8A has a heptameric structure like that of homologous pannexin channels. Unlike homomeric LRRC8A and LRRC8D channels, heptameric LRRC8C-LRRC8A(IL1(25)) channels have a large-diameter pore similar to that estimated for native VRACs, exhibit normal DCPIB pharmacology, and have higher permeability to large organic anions. Lipid-like densities are located between LRRC8C-LRRC8A(IL1(25)) subunits and occlude the channel pore. Our findings provide new insights into VRAC/LRRC8 channel structure and suggest that lipids may play important roles in channel gating and regulation.

Cryo-EM structures of an LRRC8 chimera with native functional properties reveal heptameric assembly.,Takahashi H, Yamada T, Denton JS, Strange K, Karakas E Elife. 2023 Mar 10;12:e82431. doi: 10.7554/eLife.82431. PMID:36897307<ref>PMID:36897307</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8dxq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ion channels 3D structures|Ion channels 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Denton JS]]
[[Category: Karakas E]]
[[Category: Strange K]]
[[Category: Takahashi H]]
[[Category: Yamada T]]