8DXP image
Entry Detail
PDB ID:
8DXP
EMDB ID:
Title:
Structure of LRRC8C-LRRC8A(IL125) Chimera, Class 3
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2022-08-02
Release Date:
2023-03-22
Method Details:
Experimental Method:
Resolution:
3.70 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Volume-regulated anion channel subunit LRRC8C,Volume-regulated anion channel subunit LRRC8A
Chain IDs:A, B, C, D, E, F, G
Chain Length:825
Number of Molecules:7
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Cryo-EM structures of a LRRC8 chimera with native functional properties reveal heptameric assembly.
Elife 12 ? ? (2023)
PMID: 36897307 DOI: 10.7554/eLife.82431

Abstact

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(IL125) 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(IL125) 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(IL125) 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.

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