The CACNA2D2 protein encodes the alpha2delta-2 auxiliary subunit of voltage-gated calcium channels (VGCCs). This subunit plays a critical role in modulating calcium channel trafficking, function, and pharmacology in neurons. Mutations in CACNA2D2 cause autosomal recessive neurological disorders including epilepsy, cerebellar ataxia, and autism spectrum disorders.
:: infobox .infobox-protein ===
Structure
The alpha2delta-2 protein is a unique auxiliary subunit with distinctive structural features:
Protein Architecture
Alpha2 domain (N-terminal, ~1000 aa): Large extracellular domain containing multiple protein-protein interaction motifs, including a Von Willebrand factor type A domain (vWFA)
Delta domain (C-terminal): Single transmembrane segment that anchors the protein to the plasma membrane
Disulfide bonds: Covalent linkage between alpha2 and delta domains after proteolytic processing
Post-Translational Processing
The CACNA2D2 protein is synthesized as a single precursor that undergoes proteolytic cleavage to generate mature alpha2 and delta polypeptides that remain associated through disulfide bonds. This processing is essential for proper channel assembly and function.
Normal Function
The alpha2delta-2 subunit modulates voltage-gated calcium channel activity through multiple mechanisms:
Channel Modulation
Trafficking promotion: Facilitates the transport of the main alpha1 subunit to the plasma membrane
Current amplitude enhancement: Increases the magnitude of calcium currents
Voltage dependence modification: Shifts activation/inactivation curves
Kinetics alteration: Modifies activation and inactivation time constants
[Calcium Signaling in Neurodegeneration](/mechanisms/calcium-dysregulation)
[Epilepsy Mechanisms](/diseases/epilepsy)
[Cerebellar Ataxia](/diseases/cerebellar-ataxia)
References
[Unknown, Dolphin AC. Calcium channel auxiliary α2δ and β subunits: trafficking and function (2012) (2012)](https://doi.org/10.1038/nrn3086)
[Payne HL et al., CACNA2D2 mutations cause epilepsy and autism (2015) (2015)](https://doi.org/10.1093/brain/awv146)
[Barclay J et al., Ducky mouse: a calcium channel mutation causing ataxia and epilepsy (2001) (2001)](https://doi.org/10.1016/S0896-6273(01)
[Brodbeck J et al., The ducky mutation in Cacna2d2 results in altered Purkinje cell morphology (2002) (2002)](https://doi.org/10.1523/JNEUROSCI.22-14-05955.2002)
[Wang J et al., Targeting α2δ subunits for chronic pain treatment (2019) (2019)](https://doi.org/10.1016/j.pharmthera.2019.01.002)