CaV3.3 | voltage-dependent, T type, calcium channel subunit alpha-1I
L-Type (CaV1.1–CaV1.4), P/Q-Type (CaV2.1), N-Type (CaV2.2), R-Type (CaV2.3), T-Type (CaV3.1–CaV3.3)
Six transmembrane alpha helices (S1–S6), total of four homologous domains make up the tetrameric alpha subunit structure
One large alpha subunit forms a functional channel, accessory subunits ( α1, α2δ, β1-4, and γ) are crucial for robust expression, they functionally modulate the alpha subunit
CaV3.3 Background Information
Calcium channel, voltage-dependent, T type, alpha 1I subunit, also known as CACNA1I or CaV3.3, is a low voltage-activated channel with shows a moderate voltage-dependent inactivation. The channel generates low-threshold Ca2+ spikes leading to burst firing and low-frequency oscillatory discharge. Mutations of the CACNA1L gene are associated with epilepsy. CaV3.3 may be involved in sleep regulation.
CNS ( highly expressed in thalamic reticular neurons) and PNS.
Low threshold Ca2+ spike that mediates burst firing of neurons.
Childhood Absence Epilepsy, Childhood Electroclinical Syndrome, Epilepsy
Interacts with CATSPER1 and CATSPER2, leading to suppress T-type calcium channel activity. Furthermore it interacts with CACNB1, CACNB2, CACNB3, CACNA1B, CACNA1D, CACNA1E.
Mibefradil, nickel, verapamil
Patch Clamp: whole cell, room temperature
CaV channels often show a rundown phenomenon. Adequate intra- and extracellular solutions are essential for a good data quality.
Reviews and Links
- Catterall et al. (2005) International Union of Pharmacology. XLVIII. Nomenclature and structure-function relationships of voltage-gated calcium channels. Pharmacol Rev. 57 (4): 411–25.