CACNA1E

CACNA1E is the gene that encodes the alpha‑1E subunit of the voltage‑gated Ca²⁺ channel, also known as the N‑type calcium channel α1E. This protein is a core component of the tetrameric channel complex that mediates calcium entry into excitable cells in response to membrane depolarization. The channel is predominantly expressed in neurons, where it plays a critical role in neurotransmitter release, synaptic plasticity and neuronal excitability. In pancreatic β‑cells it contributes to insulin secretion, while in cardiac myocytes it can influence calcium handling, although its expression is relatively lower in heart tissue compared with other calcium channel types.

Alternative splicing of CACNA1E generates several transcript variants that differ in their C‑terminal intracellular tail; some isoforms are enriched in the cerebellum and hippocampus, suggesting region‑specific regulatory functions. The protein contains the six repeat domain architecture characteristic of voltage‑gated calcium channels, each repeat comprising four transmembrane helices (S1–S4) and a pore‑forming loop between S5 and S6. The channel is activated by high‑voltage depolarization and is sensitive to tetrodotoxin‑like toxins such as ω‑conotoxins, which specifically block N‑type channels.

Mutations in CACNA1E have been implicated in various neurological disorders. Autosomal dominant missense variants have been associated with early‑onset epilepsy, intellectual disability, and developmental delay. A distinct set of mutations appears linked to episodic ataxia type 7, a rare neurogenetic disorder characterized by brief episodes of ataxia and dysarthria. Genome‑wide association studies have also suggested a role for common CACNA1E variants in migraine susceptibility and in the regulation of pain sensitivity. Functional studies in mouse models lacking the α1E subunit show impaired synaptic transmission and altered locomotor behavior, reinforcing its importance in neuronal function.

Because of its central role in calcium signaling, CACNA1E is a potential therapeutic target. Small‑molecule blockers of N‑type calcium channels, such as ω‑conotoxin MVIIA (ziconotide), are used clinically to treat severe chronic pain, although these drugs act at the channel level rather than modulating the gene directly. Ongoing research seeks to develop more selective modulators that could correct specific biophysical defects caused by pathogenic CACNA1E variants.