Affinage

CACNA2D2

Voltage-dependent calcium channel subunit alpha-2/delta-2 · UniProt Q9NY47

Length
1150 aa
Mass
129.8 kDa
Annotated
2026-04-28
31 papers in source corpus 18 papers cited in narrative 18 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

CACNA2D2 encodes the α2δ-2 auxiliary subunit of voltage-gated calcium channels, serving as a critical modulator of calcium channel trafficking, current amplitude, and gating across multiple CaV subtypes (CaV1.2, CaV2.1, CaV2.2, CaV3.1) in the nervous system and heart (PMID:10766861, PMID:10762351). In cerebellar Purkinje cells, α2δ-2 resides in lipid raft microdomains with CaV2.1, traffics to the plasma membrane via Rab11-dependent recycling endosomes — a pathway blocked by gabapentin/pregabalin — and is required for proper climbing fiber synapse structure, multivesicular release, and postsynaptic calcium coupling to retrograde endocannabinoid signaling and afterhyperpolarization (PMID:16928863, PMID:20861389, PMID:32086258, PMID:34783012). Beyond its canonical calcium channel role, α2δ-2 forms a direct complex with GluK1 kainate receptors via its C-terminus to promote their synaptic surface expression and current independently of calcium channel function (PMID:39439207). Loss-of-function mutations in CACNA2D2 cause epileptic encephalopathy, cerebellar ataxia, and cardiac abnormalities in mice and humans (PMID:11487633, PMID:15331424, PMID:39161180).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 2000 High

    Establishing α2δ-2 as a functional calcium channel auxiliary subunit resolved whether the newly cloned CACNA2D2 gene product modulates channel activity: co-expression potentiated current amplitude across N-type, L-type, and T-type channels and shifted voltage-dependent gating.

    Evidence Heterologous co-expression with multiple α1 subunits in Xenopus oocytes, two-electrode voltage clamp

    PMID:10762351 PMID:10766861

    Open questions at the time
    • No native tissue validation at this stage
    • Trafficking mechanism for current enhancement unknown
    • Stoichiometry of α2δ-2 in channel complexes not defined
  2. 2001 High

    The ducky mouse demonstrated that α2δ-2 is required in vivo for normal calcium channel current density in Purkinje cells and that a truncated α2δ-2 acts as a dominant-negative, linking loss of function to cerebellar pathology.

    Evidence Patch-clamp on acutely dissociated Purkinje cells from du/du mice; in vitro dominant-negative assay with truncated protein

    PMID:11487633 PMID:11756448

    Open questions at the time
    • Mechanism by which α2δ-2 controls current density (trafficking vs. channel open probability) unresolved
    • Purkinje cell dendritic morphology defects not mechanistically linked to channel function
  3. 2003 High

    The entla allele revealed that the α2-δ disulfide linkage is structurally critical: disruption halved Purkinje cell Ca2+ currents and drastically reduced gabapentin binding, linking protein structural integrity to both channel function and drug pharmacology.

    Evidence Biochemical and electrophysiological characterization of entla mice carrying a 39-amino-acid duplication; radioligand binding

    PMID:14660671

    Open questions at the time
    • Atomic-level structural basis for disulfide linkage requirement unknown
    • Whether gabapentin binding loss is cause or consequence of misfolding not distinguished
  4. 2004 High

    Targeted Cacna2d2 knockout confirmed organismal requirements for α2δ-2: cerebellar granule cell apoptosis, Purkinje cell loss, enhanced seizure susceptibility, and cardiac bradycardia established α2δ-2 as essential for CNS and cardiac physiology.

    Evidence Knockout mouse phenotyping with histopathology, EEG, and cardiac monitoring

    PMID:15331424

    Open questions at the time
    • Cell-autonomous vs. circuit-level contributions to seizures not separated
    • Cardiac mechanism (channel subtype involved) not defined
  5. 2006 High

    Discovery that α2δ-2 and CaV2.1 are concentrated in lipid raft microdomains in cerebellum, and that the R282A mutation reduces both gabapentin affinity and functional channel enhancement, established raft localization as a feature of native α2δ-2 complexes.

    Evidence Detergent-resistant membrane fractionation, co-immunoprecipitation from cerebellum, electrophysiology with R282A mutant, cholesterol depletion

    PMID:16928863

    Open questions at the time
    • Functional consequence of raft disruption in neurons not tested
    • Identity of raft-associated binding partners beyond stomatin-family not explored
  6. 2010 High

    Mechanistic dissection of gabapentin action revealed that the drug blocks α2δ-2 recycling from Rab11-positive endosomes to the plasma membrane rather than promoting internalization, identifying the specific trafficking step regulated by the drug.

    Evidence Surface trafficking assay with BBS-tagged α2δ-2, dominant-negative Rab11 co-expression, R282A mutagenesis, electrophysiology in cell lines and neurons

    PMID:20861389

    Open questions at the time
    • Whether Rab11-dependent recycling is the primary steady-state trafficking route for α2δ-2 in vivo not established
    • Molecular intermediates between gabapentin binding and Rab11 pathway blockade unknown
  7. 2011 High

    In vivo pharmacogenetic dissection using R279A knockin mice showed that pregabalin's anxiolytic effect operates through α2δ-1 rather than α2δ-2, delineating subunit-specific pharmacological roles despite shared drug binding.

    Evidence Point-mutant knockin mice (α2δ-1 R217A and α2δ-2 R279A), Vogel conflict behavioral test with pregabalin

    PMID:21558437

    Open questions at the time
    • Whether other gabapentinoid effects (analgesic, anticonvulsant) are similarly subunit-specific not addressed
    • Mechanism by which α2δ-1 vs. α2δ-2 differentially regulate anxiety circuits unknown
  8. 2020 High

    Loss of α2δ-2 was shown to reorganize climbing fiber synapse architecture — terminals relocate proximally, double their release sites, and increase multivesicular release — revealing a trans-synaptic structural role for the auxiliary subunit beyond biophysical channel modulation.

    Evidence Whole-cell patch-clamp, VGLUT2 immunofluorescence, electron microscopy, and computational modeling in Cacna2d2 KO cerebellar slices

    PMID:32086258

    Open questions at the time
    • Molecular pathway linking postsynaptic α2δ-2 loss to presynaptic structural remodeling not identified
    • Whether this trans-synaptic effect depends on calcium channel function or an independent role unresolved
  9. 2021 High

    α2δ-2 was found to be specifically required for coupling postsynaptic calcium entry to depolarization-induced suppression of excitation (DSE) and afterhyperpolarization in Purkinje cells, without affecting total calcium influx, revealing a role in calcium microdomain signaling.

    Evidence Whole-cell electrophysiology in Cacna2d2 KO Purkinje cells with pharmacological dissection of DSE and AHP

    PMID:34783012

    Open questions at the time
    • Whether α2δ-2 scaffolds endocannabinoid synthesis machinery or positions channels near specific effectors not determined
    • Calcium sensor identity for the α2δ-2-dependent coupling not identified
  10. 2024 High

    A human DEE-associated R593P mutation was shown to drastically reduce α2δ-2 membrane expression and synaptic targeting, impair presynaptic CaV2.1 abundance and calcium transients, and reduce trans-synaptic GABAA receptor recruitment, providing a mechanistic basis for the human disease mutation.

    Evidence Electrophysiology in tsA201 cells, lentiviral expression in primary hippocampal neurons, immunocytochemistry, calcium imaging, mEPSC recordings

    PMID:39161180

    Open questions at the time
    • Whether R593P represents a trafficking-deficient or folding-deficient class of mutation not resolved
    • In vivo knockin confirmation of R593P phenotype lacking
  11. 2025 High

    Discovery of a direct α2δ-2–GluK1 kainate receptor complex, mediated by the α2δ-2 C-terminus and independent of calcium channel function, fundamentally expanded the functional scope of α2δ-2 beyond voltage-gated calcium channel biology.

    Evidence Reciprocal co-immunoprecipitation from cerebellum and HEK293 cells, electrophysiology, surface expression assay, C-terminus peptide disruption, conditional CRISPR knockdown with behavioral validation

    PMID:39439207

    Open questions at the time
    • Structural basis of α2δ-2–GluK1 interaction not resolved
    • Whether other α2δ subunits interact with kainate receptors not tested
    • Synaptic consequences of GluK1 loss of surface expression via α2δ-2 mechanism in Purkinje cells not fully characterized

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include the structural basis for α2δ-2's dual roles as a calcium channel subunit and GluK1 receptor partner, the molecular identity of the trans-synaptic signaling pathway through which postsynaptic α2δ-2 controls presynaptic climbing fiber morphology, and the contribution of α2δ-2 to cardiac channel complexes.
  • No high-resolution structure of α2δ-2 in complex with CaV or GluK1
  • Trans-synaptic signaling mechanism for climbing fiber remodeling unknown
  • Cardiac α2δ-2 channel complex identity and function uncharacterized

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0098772 molecular function regulator activity 5 GO:0005215 transporter activity 3 GO:0005198 structural molecule activity 2
Localization
GO:0005886 plasma membrane 4 GO:0005768 endosome 1 GO:0031410 cytoplasmic vesicle 1
Pathway
R-HSA-112316 Neuronal System 4 R-HSA-382551 Transport of small molecules 3 R-HSA-162582 Signal Transduction 2 R-HSA-9609507 Protein localization 2
Partners
CACNA1ACACNA1CCACNA1ECACNA1GDNMT1GRIK1RAB11A
Complex memberships
CaV2.1/P-Q-type calcium channel complexα2δ-2–GluK1 kainate receptor complex

Evidence

Reading pass · 18 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2000 CACNA2D2 encodes the α2δ-2 auxiliary subunit of voltage-gated Ca2+ channels; when co-expressed with α1B/β3 in Xenopus oocytes, α2δ-2 increased peak N-type Ca2+ currents 9-fold; co-expression with α1C increased L-type currents 2-fold and with α1G increased T-type currents 1.8-fold, establishing α2δ-2 as a functional channel auxiliary subunit that potentiates current amplitude across multiple channel types. cRNA co-injection in Xenopus oocytes, electrophysiology The Journal of biological chemistry High 10766861
2000 α2δ-2 co-expression with α1C, α1E, and α1A subunits increased current density and shifted voltage dependence of activation and inactivation in a hyperpolarizing direction; co-expression with α1G accelerated decay and shifted steady-state inactivation, demonstrating gating modulation beyond simple current enhancement. Heterologous co-expression in Xenopus oocytes, electrophysiology The European journal of neuroscience High 10762351
2001 Loss-of-function mutations in Cacna2d2 (ducky mouse) reduce voltage-gated Ca2+ channel current density in cerebellar Purkinje cells without altering single-channel conductance, identifying α2δ-2 as required for normal calcium channel current amplitude specifically in Purkinje cells. Patch-clamp electrophysiology on acutely dissociated Purkinje cells from du/du mice; genetic mapping and sequencing The Journal of neuroscience High 11487633
2001 The truncated ducky α2δ-2 protein (encoded by first 3 exons + 8 novel amino acids due to premature stop) acts as a dominant-negative when co-expressed with CaV2.1/β4 in vitro, reducing current density, whereas wild-type α2δ-2 increases it; du/du Purkinje cells show abnormal dendritic tree morphology. In vitro co-expression assay (Xenopus oocytes), Western blot detection of truncated protein, Purkinje cell morphology analysis in du/du mice The Journal of biological chemistry High 11756448
2003 The entla allele of Cacna2d2 encodes a full-length protein with a 39-amino-acid duplication near the N-terminus that disrupts the disulfide linkage between the α2 and δ portions; this results in 50% reduction in Ca2+ current density in Purkinje cells and >60% reduction in [3H]gabapentin maximum binding to cerebellar membranes. Western blot, patch-clamp electrophysiology on Purkinje cells, radioligand binding assay with [3H]gabapentin The Journal of biological chemistry High 14660671
2004 Targeted disruption of Cacna2d2 in mice causes cerebellar granule cell apoptosis followed by Purkinje cell depletion, enhanced seizure susceptibility, and cardiac abnormalities including bradycardia, genetically demonstrating that α2δ-2 functions as an in vivo component of P/Q-type calcium channels essential for CNS and cardiac function. Knockout mouse phenotyping: histopathology, EEG, cardiac monitoring The American journal of pathology High 15331424
2006 α2δ-2 is completely concentrated in cholesterol-rich lipid raft microdomains in cerebellum, where it colocalizes with and co-immunoprecipitates with CaV2.1 and stomatin-family proteins; cholesterol depletion disrupts rafts and enhances CaV2.1/α2δ-2/β4 currents; a point mutation (R282A) reduces gabapentin affinity and reduces functional enhancement of CaV2.1 currents, linking raft association and gabapentin-binding site integrity to α2δ-2 function. Detergent-resistant membrane fractionation, co-immunoprecipitation, electrophysiology, cholesterol depletion, point mutagenesis The Journal of neuroscience High 16928863
2010 Gabapentin specifically blocks the recycling of α2δ-2 from Rab11-positive recycling endosomes to the plasma membrane (not internalization); this effect requires gabapentin binding to α2δ-2 (abrogated by R282A mutation) and is prevented by dominant-negative Rab11 S25N, leading to reduced α2δ-2 cell-surface levels and reduced calcium channel currents. α-bungarotoxin binding site-tagged α2δ-2 surface trafficking assay, dominant-negative Rab11 co-expression, electrophysiology in cell lines and primary neurons The Journal of neuroscience High 20861389
2011 Pregabalin's anxiolytic-like effect in the Vogel conflict test is mediated through the α2δ-1 subunit, not α2δ-2: α2δ-1 R217A knockin mice are insensitive to pregabalin whereas α2δ-2 R279A knockin mice retain pregabalin response, establishing the binding-site specificity for in vivo pharmacological action. Point-mutant knockin mouse strains (R217A and R279A), behavioral pharmacology (Vogel conflict test) The Journal of pharmacology and experimental therapeutics High 21558437
2020 Loss of α2δ-2 in Purkinje cells alters climbing fiber (CF) synapse structure and function: CF terminals relocate more proximally on dendrites, CF terminals show twice as many vesicle release sites (by EM), multivesicular transmission increases, and CF-evoked EPSC amplitude increases with faster decay due to enhanced glutamate reuptake, collectively degrading complex spike information transfer and contributing to ataxia. Whole-cell patch-clamp in acute cerebellar slices from Cacna2d2 KO mice, VGLUT2 immunofluorescence, electron microscopy, computational modeling The Journal of neuroscience High 32086258
2021 α2δ-2 is required for functional coupling of postsynaptic voltage-dependent calcium entry to depolarization-induced suppression of excitation (DSE, via retrograde endocannabinoid signaling) and to spike afterhyperpolarization in Purkinje cells; loss of α2δ-2 disrupts these calcium-dependent signaling outputs without affecting total calcium influx. Whole-cell patch-clamp recordings in Cacna2d2 KO mouse Purkinje cells, pharmacological dissection of DSE and AHP The Journal of physiology High 34783012
2024 The DEE-associated p.R593P (mouse R596P) mutation in α2δ-2 drastically decreases membrane expression and synaptic targeting of α2δ-2, alters biophysical properties of postsynaptic CaV1.3 channels, reduces presynaptic CaV2.1 abundance and presynaptic calcium transients in hippocampal neurons, reduces trans-synaptic recruitment of GABAA receptors and presynaptic synapsin clustering at glutamatergic synapses, and decreases amplitudes of glutamatergic miniature PSCs. Heterologous expression in tsA201 cells (electrophysiology), primary hippocampal neuron culture with lentiviral transduction, immunocytochemistry, calcium imaging, mEPSC recordings Journal of neurochemistry High 39161180
2025 α2δ-2 forms a direct protein complex with GluK1 (but not GluK2) kainate receptors via its C-terminus, independently of its role as a calcium channel subunit; α2δ-2 co-expression augments GluK1 currents in HEK293 cells and promotes surface expression of GluK1; pregabalin binding to α2δ-2 abrogates this augmentation; conditional Purkinje cell knockdown of Cacna2d2 or Grik1 impairs motor coordination. Co-immunoprecipitation from cerebellar tissue and HEK293 cells, whole-cell patch-clamp in HEK293 and Purkinje cells, surface expression assay, CRISPR/Cas9 conditional knockdown, rotarod/beam-walking behavioral testing, α2δ-2 C-terminus peptide disruption Brain : a journal of neurology High 39439207
2003 CACNA2D2 overexpression in 3p21.3-deficient NSCLC cells elevates intracellular free Ca2+, causes mitochondrial membrane depolarization prior to apoptosis, and triggers cytochrome c release, caspase-3 activation, and PARP cleavage, linking α2δ-2 to a Ca2+-dependent mitochondrial apoptosis pathway in cancer cells. Adenoviral vector-mediated gene transfer, intracellular Ca2+ measurement, mitochondrial membrane potential assay, cytochrome c immunoblot, caspase-3 activity assay Oncogene Medium 12555074
2019 The lncRNA MIR210HG promotes CACNA2D2 promoter methylation by recruiting DNMT1; MIR210HG knockdown increases CACNA2D2 expression and inhibits NSCLC cell proliferation, an effect reversed by CACNA2D2 knockdown, positioning CACNA2D2 as an epigenetically silenced growth suppressor downstream of MIR210HG-DNMT1. RNA binding protein immunoprecipitation (RIP), chromatin immunoprecipitation (ChIP), bisulfite sequencing, siRNA knockdown, rescue experiments OncoTargets and therapy Medium 31190878
2024 circMYLK4 physically interacts with CACNA2D2 protein, inhibiting Ca2+ release from the sarcoplasmic reticulum in skeletal muscle, which decreases cytoplasmic Ca2+, suppresses glycogen breakdown enzymes PHKB and PHKG1, and shifts metabolism from glycolysis to mitochondrial oxidative phosphorylation. Multi-omics (transcriptomics, proteomics, phosphoproteomics, metabolomics), RNA pulldown/RIP to identify circMYLK4-CACNA2D2 interaction, intracellular Ca2+ measurement The Journal of biological chemistry Medium 38823637
2017 miR-1231 targets Cacna2d2 and suppresses its expression in ischemic hearts; knockdown of miR-1231 ameliorates arrhythmias in rat MI hearts, while Cacna2d2 knockdown alone induces arrhythmias despite miR-1231 inhibition, placing Cacna2d2 downstream of miR-1231 in the regulation of cardiac rhythm. miRNA target prediction validated by gene expression array, in vivo miR-1231 inhibition/overexpression in rat MI model, Cacna2d2 siRNA knockdown, ECG recording American journal of translational research Medium 28469787
2022 Following surgical decompression in a rat cervical spondylotic myelopathy model, α2δ-2 expression decreases in the anterior horn while axonal regeneration markers (5HT, GAP43) increase; gabapentin-mediated inhibition of α2δ-2 after decompression further enhances axonal regeneration and functional recovery, identifying α2δ-2 as an inhibitor of axonal regeneration in the injured spinal cord. Western blot and immunofluorescence for α2δ-2, 5HT, and GAP43 in rat spinal cord; gabapentin pharmacological intervention; behavioral assessment BMC neuroscience Low 35778700

Source papers

Stage 0 corpus · 31 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2001 Ducky mouse phenotype of epilepsy and ataxia is associated with mutations in the Cacna2d2 gene and decreased calcium channel current in cerebellar Purkinje cells. The Journal of neuroscience : the official journal of the Society for Neuroscience 243 11487633
2000 Functional properties of a new voltage-dependent calcium channel alpha(2)delta auxiliary subunit gene (CACNA2D2). The Journal of biological chemistry 145 10766861
2006 The calcium channel alpha2delta-2 subunit partitions with CaV2.1 into lipid rafts in cerebellum: implications for localization and function. The Journal of neuroscience : the official journal of the Society for Neuroscience 125 16928863
2001 The ducky mutation in Cacna2d2 results in altered Purkinje cell morphology and is associated with the expression of a truncated alpha 2 delta-2 protein with abnormal function. The Journal of biological chemistry 120 11756448
2010 The alpha2delta ligand gabapentin inhibits the Rab11-dependent recycling of the calcium channel subunit alpha2delta-2. The Journal of neuroscience : the official journal of the Society for Neuroscience 114 20861389
2000 Neuronal distribution and functional characterization of the calcium channel alpha2delta-2 subunit. The European journal of neuroscience 99 10762351
2004 Cerebellar ataxia, seizures, premature death, and cardiac abnormalities in mice with targeted disruption of the Cacna2d2 gene. The American journal of pathology 78 15331424
2013 A novel null homozygous mutation confirms CACNA2D2 as a gene mutated in epileptic encephalopathy. PloS one 72 24358150
2003 CACNA2D2-mediated apoptosis in NSCLC cells is associated with alterations of the intracellular calcium signaling and disruption of mitochondria membrane integrity. Oncogene 72 12555074
2003 entla, a novel epileptic and ataxic Cacna2d2 mutant of the mouse. The Journal of biological chemistry 72 14660671
2019 LncRNA MIR210HG promotes proliferation and invasion of non-small cell lung cancer by upregulating methylation of CACNA2D2 promoter via binding to DNMT1. OncoTargets and therapy 66 31190878
2015 CACNA2D2 promotes tumorigenesis by stimulating cell proliferation and angiogenesis. Oncogene 44 25619833
2011 Anxiolytic-like activity of pregabalin in the Vogel conflict test in α2δ-1 (R217A) and α2δ-2 (R279A) mouse mutants. The Journal of pharmacology and experimental therapeutics 41 21558437
2020 α2δ-2 Protein Controls Structure and Function at the Cerebellar Climbing Fiber Synapse. The Journal of neuroscience : the official journal of the Society for Neuroscience 26 32086258
2019 Biallelic CACNA2D2 variants in epileptic encephalopathy and cerebellar atrophy. Annals of clinical and translational neurology 26 31402629
2018 Epileptic Encephalopathy and Cerebellar Atrophy Resulting from Compound Heterozygous CACNA2D2 Variants. Case reports in genetics 20 30410802
2016 Do Copy Number Changes in CACNA2D2, CACNA2D3, and CACNA1D Constitute a Predisposing Risk Factor for Alzheimer's Disease? Frontiers in genetics 17 27379157
2017 miR-1231 exacerbates arrhythmia by targeting calciumchannel gene CACNA2D2 in myocardial infarction. American journal of translational research 15 28469787
2021 α2δ-2 is required for depolarization-induced suppression of excitation in Purkinje cells. The Journal of physiology 8 34783012
2024 A biallelic mutation in CACNA2D2 associated with developmental and epileptic encephalopathy affects calcium channel-dependent as well as synaptic functions of α2δ-2. Journal of neurochemistry 7 39161180
2016 Genetic susceptibility to postherniotomy pain. The influence of polymorphisms in the Mu opioid receptor, TNF-α, GRIK3, GCH1, BDNF and CACNA2D2 genes. Scandinavian journal of pain 5 28850479
2023 MicroRNA-423-5p Mediates Cocaine-Induced Smooth Muscle Cell Contraction by Targeting Cacna2d2. International journal of molecular sciences 4 37047559
2020 Association of the CACNA2D2 gene with schizophrenia in Chinese Han population. PeerJ 4 32071821
2025 α2δ-2 regulates synaptic GluK1 kainate receptors in Purkinje cells and motor coordination. Brain : a journal of neurology 3 39439207
2024 Circular RNA circMYLK4 shifts energy metabolism from glycolysis to OXPHOS by binding to the calcium channel auxiliary subunit CACNA2D2. The Journal of biological chemistry 3 38823637
2025 iPSC screening identifies CACNA2D2 as a potential therapeutic target for FTLD-Tau. European journal of cell biology 2 40158290
2024 Altered Hippocampal Activation in Seizure-Prone CACNA2D2 Knock-out Mice. eNeuro 1 38749701
2023 Altered hippocampal activation in seizure-prone CACNA2D2 knockout mice. bioRxiv : the preprint server for biology 1 37986872
2022 Cacna2d2 inhibits axonal regeneration following surgical decompression in a rat model of cervical spondylotic myelopathy. BMC neuroscience 1 35778700
2026 A CACNA2D2-Related Recessive Form of Cerebellar Abiotrophy in Angus Cattle. Animal genetics 0 41873845
2026 CACNA2D2 rs56287038:G>T and SCN1A rs2298771:C>T Variants Are Associated with Antiseizure Medication Response in Turkish Epilepsy Patients : A Pilot Study. Neuropsychobiology 0 41961764