Voltage-gated Ca²⁺ channels (Ca_V), enable the passage of Ca²⁺ ions in a voltage-dependent manner. These heteromeric entities are formed in part by the pore-forming α1 subunit which determines the biophysical and pharmacological properties of the channel¹.

Ca_V1 and Ca_V2 channels are high-voltage activated (HVA) Ca_V channels. The a1 subunit of these channels normally interacts and associates with α2δ subunit, a membrane anchored protein and Ca_Vβ, a cytosolic protein¹.

Four α2δ subunits have been cloned to date: α2δ1-4. This subunit originates from a single gene. The corresponding protein is modified by post-translational cleavage yielding a α2 subunit which is disulfide bonded to the δ subunit². All α2δ subunits are GPI- (glycosylphosphatidylinositol) anchored proteins³. The role of this subunit is important for the membrane trafficking of the α1 subunit, and also has a role in influencing the biophysical properties of the channel¹.

α2δ can be expressed as various splice variants and expressed in a tissue specific manner. α2δ2 can be detected in the brain, heart, lung, spleen and liver⁴.

Gabapentin and pregabalin are two commonly used anti-epileptic drugs. They act on Ca_V channels via the α2δ1 and α2δ2 subunits by disturbing their membrane trafficking, thereby decreasing Ca²⁺ currents.