Affinage

LRRC8D

Volume-regulated anion channel subunit LRRC8D · UniProt Q7L1W4

Length
858 aa
Mass
98.2 kDa
Annotated
2026-06-10
39 papers in source corpus 15 papers cited in narrative 15 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

LRRC8D is a facultative pore-forming subunit of heteromeric volume-regulated anion channels (VRACs), which it forms by assembling at the plasma membrane with the obligatory LRRC8A subunit (and LRRC8B/C) (PMID:24782309, PMID:26530471). Cryo-EM of a native-like LRRC8A:D channel with 4:2 stoichiometry shows that incorporation of LRRC8D widens the extracellular selectivity-filter constriction and increases pore hydrophobicity relative to LRRC8A homomers, the structural basis for its distinctive substrate profile [PMID:32415200, PMID:bio_10.1101_2024.11.24.625074]. Functionally, LRRC8D-containing channels confer elevated permeability to uncharged organic osmolytes such as taurine and myo-inositol and to platinum-based drugs (cisplatin, carboplatin), while charged osmolyte release depends on LRRC8A/C/E channels (PMID:26530471, PMID:28833202). This drug-permeation activity is physiologically and clinically consequential: LRRC8D-mediated platinum uptake drives DNA damage in tumor cells, and its loss confers in vivo platinum resistance (PMID:36467895), and the activity requires N-terminal acetylation of LRRC8A/D by the Golgi acetyltransferase NAA60 (PMID:41053424). LRRC8D incorporation conversely suppresses channel transport of the immune second messenger cGAMP (PMID:33171122). LRRC8D-containing channels are gated and modulated by their environment — directly inhibited by oxidation of extracellular-loop cysteines (PMID:28841766, PMID:33932953), and lipid-occupied in the closed state with LRRC8D-induced lateral fenestrations proposed to permit pore lipid evacuation upon activation [PMID:bio_10.1101_2024.11.24.625074]. In vivo, LRRC8A/D channels reside at the basolateral membrane of renal proximal tubules where they are required for export of organic metabolites (PMID:35777784), and combined loss of LRRC8D and LRRC8E causes cochlear degeneration and congenital deafness with collapse of the endocochlear potential (PMID:38838775).

Mechanistic history

Synthesis pass · year-by-year structured walk · 15 steps
  1. 2014 Medium

    Established that LRRC8D has a transport function and physically assembles with other LRRC8 family members, answering whether LRRC8D is a plasma-membrane transport component.

    Evidence Genetic loss-of-function screen for blasticidin S import plus co-immunoprecipitation and topology assays in mammalian cells

    PMID:24782309

    Open questions at the time
    • Did not define the channel identity or that VRAC is the relevant conductance
    • Substrate scope limited to blasticidin S at this stage
  2. 2015 High

    Identified LRRC8D as a VRAC subunit that shapes pore permeability, answering how LRRC8D contributes to anion-channel function and explaining its role in chemotherapy uptake.

    Evidence CRISPR/siRNA knockout, isotopic platinum-drug uptake assays, electrophysiology and genetic rescue

    PMID:26530471

    Open questions at the time
    • Structural basis of altered permeability not yet resolved
    • Stoichiometry of LRRC8D within the hexamer undefined
  3. 2017 Medium

    Showed subunit-specific substrate selectivity, answering which osmolytes LRRC8D-containing channels preferentially conduct versus other heteromers.

    Evidence RNAi knockdown with radiotracer flux of taurine, myo-inositol and d-aspartate under hypoosmotic challenge in primary astrocytes

    PMID:28833202

    Open questions at the time
    • Selectivity inferred from knockdown rather than reconstituted defined channels
    • Single cell type
  4. 2017 Medium

    Defined redox regulation of LRRC8D channels, answering how oxidation differentially modulates VRAC heteromers and localizing the oxidation-sensitive sites.

    Evidence Electrophysiology of defined fluorescently tagged heteromers with pharmacological oxidation and domain-swap chimeras

    PMID:28841766 PMID:33932953

    Open questions at the time
    • Specific cysteine residues conferring inhibition not fully enumerated
    • Physiological oxidant relevant in vivo not established
  5. 2018 Medium

    Mapped the first extracellular loop as essential for channel activity, answering which LRRC8D domain enables functional VRAC assembly and gating.

    Evidence Chimeric channel mutagenesis with whole-cell patch clamp under hypotonicity

    PMID:29853476

    Open questions at the time
    • Mechanism by which EL1 confers volume sensing unresolved
    • Single-subunit chimera context
  6. 2018 Medium

    Implicated LRRC8D channels in pancreatic islet signaling, addressing a physiological context for LRRC8D-containing VRAC activity.

    Evidence Conditional LRRC8A knockout mice with patch-clamp, insulin secretion and glucose tolerance tests

    PMID:29773801

    Open questions at the time
    • LRRC8D role inferred from expression and partnership, not direct LRRC8D knockout
    • Permeant signaling molecule not directly identified
  7. 2020 High

    Provided a structural explanation for LRRC8D permeability, answering why LRRC8D channels conduct large organic substrates.

    Evidence Cryo-EM of the human LRRC8D homo-hexamer with structure-based electrophysiological mutagenesis

    PMID:32415200

    Open questions at the time
    • Homo-hexamer is not the physiological heteromeric assembly
    • Gating transitions not captured
  8. 2020 Medium

    Showed LRRC8D inhibits cGAMP transport, answering how subunit composition selects against immune second-messenger permeation.

    Evidence CRISPR knockout screens, subunit rescue, cGAMP transport assays and STING activation readouts

    PMID:33171122

    Open questions at the time
    • Structural basis for cGAMP exclusion by LRRC8D not defined
    • Single-lab functional inference
  9. 2021 Medium

    Linked LRRC8D to inflammatory signaling, answering whether LRRC8D-containing channels modulate Nox1/NF-κB pathways.

    Evidence Co-immunoprecipitation with Nox1, siRNA knockdown, NF-κB reporter and superoxide assays in vascular smooth muscle cells

    PMID:33932953

    Open questions at the time
    • Co-IP without reciprocal validation
    • Direct versus indirect modulation of NF-κB unresolved
  10. 2022 High

    Established an in vivo physiological role in the kidney, answering whether LRRC8A/D channels export metabolites at the basolateral proximal tubule membrane.

    Evidence Epitope-tagged knock-in localization and constitutive Lrrc8d knockout mice with histology and urine/serum metabolomics

    PMID:35777784

    Open questions at the time
    • Specific exported metabolites only partially defined
    • Tissue-specific contribution versus systemic effects not fully separated
  11. 2022 Medium

    Demonstrated in vivo chemotherapy relevance, answering whether LRRC8D loss confers platinum resistance and whether LRRC8D is dispensable for organismal viability.

    Evidence Conditional/constitutive knockout mice with platinum uptake, DNA damage assays and tumor treatment

    PMID:36467895

    Open questions at the time
    • Mechanism of residual platinum uptake via other subunits not quantified
    • Clinical translation untested
  12. 2024 Medium

    Defined a cochlear requirement, answering the in vivo consequence of losing LRRC8D-containing channels in the inner ear.

    Evidence Conditional LRRC8D/E double knockout mice with auditory brainstem response, endocochlear potential measurement and immunohistochemistry

    PMID:38838775

    Open questions at the time
    • Glutathione as the critical transported metabolite is inferential
    • LRRC8D-specific contribution versus LRRC8E not separated
  13. 2024 Medium

    Resolved the native-like heteromeric architecture and lipid-gating, answering how LRRC8D incorporation alters the pore and channel dynamics in the physiological 4:2 assembly.

    Evidence Cryo-EM of LRRC8A:D VRAC at 4:2 stoichiometry with electrophysiology (preprint)

    PMID:bio_10.1101_2024.11.24.625074

    Open questions at the time
    • Preprint, not peer-reviewed
    • Lipid-evacuation gating model awaits independent confirmation
  14. 2025 Medium

    Identified N-terminal acetylation as a required post-translational modification, answering how LRRC8A/D channels are regulated for drug uptake.

    Evidence Co-IP/mass spectrometry, acetylation and charge-substitution mutagenesis, drug uptake assays and in vivo tumor models

    PMID:41053424

    Open questions at the time
    • Mechanism by which N-terminal charge affects gating/permeation not structurally defined
    • Single-lab finding
  15. 2025 Low

    Proposed a neural stem cell signaling role, addressing whether LRRC8D modulates GABA/chloride transport in a defined circuit.

    Evidence Immunohistochemistry, in vivo circuit activation and proliferation/behavioral readouts

    PMID:40136675

    Open questions at the time
    • Correlative localization without direct biochemical dissection of LRRC8D's molecular role
    • GABA permeation through LRRC8D channels not directly measured

Open questions

Synthesis pass · forward-looking unresolved questions
  • How LRRC8D subunit incorporation is regulated to tune channel composition and substrate selectivity across tissues, and the gating transitions linking volume sensing, lipid evacuation and pore opening, remain unresolved.
  • No structure of an open/activated heteromeric channel
  • Signals controlling tissue-specific subunit assembly unknown
  • Full physiological substrate repertoire incomplete

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0005215 transporter activity 5 GO:0005198 structural molecule activity 2
Localization
GO:0005886 plasma membrane 3 GO:0031410 cytoplasmic vesicle 1
Pathway
R-HSA-382551 Transport of small molecules 4 R-HSA-8953897 Cellular responses to stimuli 3
Complex memberships
Volume-regulated anion channel (VRAC) LRRC8A:D heteromer

Evidence

Reading pass · 15 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2014 LRRC8D is required for import of the antibiotic blasticidin S into mammalian cells, demonstrating a transport function. LRRC8D localizes to the plasma membrane and physically interacts with LRRC8A, LRRC8B, and LRRC8C. Genetic screen/loss-of-function, co-immunoprecipitation, localization and topology assays The Journal of biological chemistry Medium 24782309
2015 LRRC8D is a subunit of heteromeric volume-regulated anion channels (VRACs). LRRC8A/LRRC8D-containing VRACs mediate ~50% of cellular cisplatin/carboplatin uptake under isotonic conditions, and cell swelling strongly enhances this uptake. Incorporation of LRRC8D increases VRAC permeability for cisplatin and taurine relative to channels lacking LRRC8D, indicating LRRC8D contributes to pore properties. CRISPR/siRNA knockout, isotopic drug uptake assays, electrophysiology, genetic rescue The EMBO journal High 26530471
2017 In primary rat astrocytes, LRRC8A/D-containing heteromeric VRACs preferentially mediate swelling-activated release of uncharged osmolytes (taurine, myo-inositol), whereas charged osmolyte (d-aspartate) release depends on LRRC8A/C/E-containing channels. LRRC8D knockdown strongly inhibits taurine and myo-inositol efflux without major effect on d-aspartate efflux, establishing subunit-specific substrate selectivity. RNAi knockdown, radiotracer flux assays with hypoosmotic challenge The Journal of physiology Medium 28833202
2017 LRRC8A/D heteromeric channels are strongly inhibited by oxidation of intracellular cysteine residues (by chloramine-T or tert-butyl hydroperoxide), in contrast to LRRC8A/E heteromers which are potentiated. The extracellular loop domains (EL1, EL2) of LRRC8D contain external oxidation sites that confer susceptibility to oxidant-mediated inhibition. Electrophysiology of heterologously expressed fluorescently tagged LRRC8 heteromers, pharmacological oxidation, domain-swap chimeras The Journal of physiology Medium 28841766 33932953
2018 Pancreatic islets prominently express LRRC8D alongside LRRC8A; LRRC8D-containing VRACs may mediate neurotransmitter-permeable channel activity in beta-cells, contributing to autocrine/paracrine signaling within islets. Loss of the essential subunit LRRC8A (which partners with LRRC8D) reduces first-phase glucose-induced insulin secretion and impairs glucose tolerance. Conditional knockout mice, patch-clamp electrophysiology, insulin secretion assays, glucose tolerance tests Nature communications Medium 29773801
2018 The first extracellular loop (EL1) of LRRC8D (connecting transmembrane domains 1 and 2) is essential for VRAC activity. Chimeric channels in which EL1 of LRRC8A is replaced with that of LRRC8D confer functional VRAC activity and volume-dependent regulation. Chimeric channel mutagenesis, whole-cell patch clamp, hypotonicity-induced current recording The Journal of general physiology Medium 29853476
2020 Cryo-EM structure of the human LRRC8D homo-hexamer reveals a two-fold symmetric arrangement. The extracellular pore constriction of LRRC8D is wider than in LRRC8A structures, explaining increased permeability for organic substrates. An N-terminal helix protrudes into the pore from the intracellular side and is implicated in gating. Structure-based electrophysiological mutagenesis confirmed these functional features. Cryo-EM structure determination, electrophysiology (structure-based mutagenesis) Communications biology High 32415200
2020 LRRC8D inhibits cGAMP transport through VRAC. LRRC8A:C and LRRC8A:E heteromers transport cGAMP and other 2'3'-cyclic dinucleotides, whereas LRRC8D incorporation into the complex reduces this transport activity. CRISPR knockout screens, genetic rescue with individual subunits, cGAMP transport assays, STING pathway activation readout Molecular cell Medium 33171122
2021 LRRC8D co-immunoprecipitates with NADPH oxidase 1 (Nox1) in vascular smooth muscle cells and co-localizes with Nox1 at the plasma membrane and in vesicles. LRRC8D knockdown potentiates NF-κB activation in response to TNFα, suggesting LRRC8D-containing VRACs negatively modulate this inflammatory signaling pathway. Co-immunoprecipitation, siRNA knockdown, NF-κB reporter assay, superoxide production assay The Journal of physiology Medium 33932953
2022 LRRC8D localizes to basolateral membranes of proximal tubules in the kidney. Constitutive deletion of Lrrc8d in mice causes proximal tubular injury, increased diuresis, and mild Fanconi-like symptoms, establishing LRRC8A/D channels as required for basolateral exit of organic compounds including metabolites in proximal tubules. Epitope-tagged knock-in mice for localization, constitutive Lrrc8d knockout mice, histology, urine/serum metabolomics Journal of the American Society of Nephrology : JASN High 35777784
2022 Loss of LRRC8D significantly reduces cis- and carboplatin uptake in BRCA1;p53-deficient mouse mammary tumor cells, resulting in reduced DNA damage and in vivo drug resistance. Lrrc8d deletion in mice does not affect viability or fertility, unlike Lrrc8a deletion. Conditional/constitutive gene knockout in mice, platinum drug uptake measurement, DNA damage assays, in vivo tumor treatment Cancer research communications Medium 36467895
2024 In the cochlea, LRRC8D is expressed in sensory hair cells and in the stria vascularis (alongside LRRC8A and LRRC8E). Combined ablation of LRRC8D and LRRC8E results in cochlear degeneration and congenital deafness, with severe reduction in the endocochlear potential and loss of Kir4.1 (KCNJ10) expression, suggesting LRRC8D-containing VRACs transport metabolites (e.g., glutathione) needed to maintain inner ear redox potential. Conditional knockout mice, auditory brainstem response, endocochlear potential measurement, immunohistochemistry, Western blot The Journal of biological chemistry Medium 38838775
2025 NAA60, an N-terminal acetyltransferase localized to the Golgi apparatus, acetylates the N-termini of LRRC8A and LRRC8D. Loss of NAA60 decreases cis- and carboplatin uptake; introduction of positively charged amino acids at the LRRC8A/D N-termini (mimicking absence of acetylation) similarly decreases platinum drug sensitivity, establishing N-terminal acetylation as a post-translational modification required for LRRC8A/D-mediated drug uptake. Co-immunoprecipitation/mass spectrometry, N-terminal acetylation assays, site-directed mutagenesis (charge substitution), drug uptake assays, in vivo tumor models Communications biology Medium 41053424
2024 Cryo-EM structures of a native-like LRRC8A:D VRAC with 4:2 stoichiometry reveal that LRRC8D subunits increase hydrophobicity and widen the selectivity filter compared to LRRC8A homomers, explaining LRRC8D-unique substrate selectivity. Lipids occupy the pore in the closed state (as in LRRC8A:C VRACs). Incorporation of LRRC8D disrupts packing of cytoplasmic LRR domains, increases channel dynamics, and opens lateral fenestrations proposed to be necessary for pore lipid evacuation and channel activation. Electrophysiology confirmed lipid-gating is a general VRAC property. Cryo-EM structure determination (4:2 stoichiometry), electrophysiology bioRxivpreprint Medium bio_10.1101_2024.11.24.625074
2025 In lateral ventricular neural stem cells, LRRC8D (a core VRAC component) participates in GABA transport/signaling and provides negative feedback to ChAT+ neurons in the ACC-subependymal circuit, with evidence that LRRC8D-regulated chloride and GABA transport modulates neural stem cell proliferation. Immunohistochemistry, in vivo circuit activation, functional behavioral/proliferation readouts Cells Low 40136675

Source papers

Stage 0 corpus · 39 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2015 Subunit composition of VRAC channels determines substrate specificity and cellular resistance to Pt-based anti-cancer drugs. The EMBO journal 225 26530471
2020 LRRC8A:C/E Heteromeric Channels Are Ubiquitous Transporters of cGAMP. Molecular cell 155 33171122
2018 LRRC8/VRAC anion channels enhance β-cell glucose sensing and insulin secretion. Nature communications 85 29773801
2017 Molecular composition and heterogeneity of the LRRC8-containing swelling-activated osmolyte channels in primary rat astrocytes. The Journal of physiology 85 28833202
2015 VRAC: molecular identification as LRRC8 heteromers with differential functions. Pflugers Archiv : European journal of physiology 70 26635246
2014 The protein synthesis inhibitor blasticidin s enters mammalian cells via leucine-rich repeat-containing protein 8D. The Journal of biological chemistry 67 24782309
2017 Subunit-dependent oxidative stress sensitivity of LRRC8 volume-regulated anion channels. The Journal of physiology 48 28841766
2004 LRRC8 involved in B cell development belongs to a novel family of leucine-rich repeat proteins. FEBS letters 47 15094057
2020 Cryo-EM structure of the volume-regulated anion channel LRRC8D isoform identifies features important for substrate permeation. Communications biology 44 32415200
2018 Intracellular and extracellular loops of LRRC8 are essential for volume-regulated anion channel function. The Journal of general physiology 39 29853476
2016 Specific and essential but not sufficient roles of LRRC8A in the activity of volume-sensitive outwardly rectifying anion channel (VSOR). Channels (Austin, Tex.) 33 27764579
2021 Mechanisms of Activation of LRRC8 Volume Regulated Anion Channels. Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology 29 33577730
2020 Volume-regulated anion channel as a novel cancer therapeutic target. International journal of biological macromolecules 26 32442571
2017 Leucine-rich repeat-containing 8B protein is associated with the endoplasmic reticulum Ca2+ leak in HEK293 cells. Journal of cell science 25 28972132
2020 LRRC8A homohexameric channels poorly recapitulate VRAC regulation and pharmacology. American journal of physiology. Cell physiology 23 33356947
2023 A target discovery pipeline identified ILT3 as a target for immunotherapy of multiple myeloma. Cell reports. Medicine 22 37467717
2021 Oxidant-resistant LRRC8A/C anion channels support superoxide production by NADPH oxidase 1. The Journal of physiology 22 33932953
2022 Renal Deletion of LRRC8/VRAC Channels Induces Proximal Tubulopathy. Journal of the American Society of Nephrology : JASN 20 35777784
2016 Distinct contributions of LRRC8A and its paralogs to the VSOR anion channel from those of the ASOR anion channel. Channels (Austin, Tex.) 17 27579940
2020 Identification of differentially expressed and methylated genes associated with rheumatoid arthritis based on network. Autoimmunity 16 32650679
2022 Recent Advances in the Structural Biology of the Volume-Regulated Anion Channel LRRC8. Frontiers in pharmacology 15 35645818
2022 Loss of the volume-regulated anion channel components LRRC8A and LRRC8D limits platinum drug efficacy. Cancer research communications 13 36467895
2022 Differential methylation patterns in lean and obese non-alcoholic steatohepatitis-associated hepatocellular carcinoma. BMC cancer 13 36474183
2009 Molecular signature of cell cycle exit induced in human T lymphoblasts by IL-2 withdrawal. BMC genomics 13 19505301
2009 Comparison between the stochastic search variable selection and the least absolute shrinkage and selection operator for genome-wide association studies of rheumatoid arthritis. BMC proceedings 13 20018011
2020 Generation of Stable cisPt Resistant Lung Adenocarcinoma Cells. Pharmaceuticals (Basel, Switzerland) 9 32485798
2023 Epigenome-Wide Association Study Reveals CpG Sites Associated with Thyroid Function and Regulatory Effects on KLF9. Thyroid : official journal of the American Thyroid Association 8 36719767
2022 Circuit-wide proteomics profiling reveals brain region-specific protein signatures in the male WKY rats with endogenous depression. Journal of affective disorders 8 36162674
2018 Determination of the mutational landscape in Taiwanese patients with papillary thyroid cancer by whole-exome sequencing. Human pathology 8 29753010
2015 VRACs swallow platinum drugs. The EMBO journal 8 26564094
2024 LRRC8/VRAC volume-regulated anion channels are crucial for hearing. The Journal of biological chemistry 5 38838775
2026 Endothelial LRRC8C Associates With LRRC8A and LRRC8B to Regulate Vascular Reactivity and Blood Pressure. Hypertension (Dallas, Tex. : 1979) 2 41636028
2025 Endothelial LRRC8C associates with LRRC8A and LRRC8B to regulate vascular reactivity and blood pressure. bioRxiv : the preprint server for biology 2 40894750
2025 Subunit-specific roles of LRRC8 proteins in determining glutamate permeability of astrocytic volume-regulated anion channels. bioRxiv : the preprint server for biology 1 40766626
2026 Multi-omics integration identifies NK cell dysregulation and a five-gene diagnostic signature in major depressive disorder. Frontiers in immunology 0 41601671
2026 Subunit-specific roles of LRRC8 proteins in determining glutamate permeability of astrocytic volume-regulated anion channels. American journal of physiology. Cell physiology 0 41740631
2025 Lateral Ventricular Neural Stem Cells Provide Negative Feedback to Circuit Activation Through GABAergic Signaling. Cells 0 40136675
2025 NAA60 facilitates LRRC8A- and LRRC8D-mediated platinum drug uptake. Communications biology 0 41053424
2025 Chromothriptic Translocation t(1;18): A Paradigm of Genomic Complexity in a Child with Normal Intellectual Development and Pyridoxine-Dependent Epilepsy. Genes 0 41300786

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