Cacna1a
Domain
Each of the four internal repeats contains five hydrophobic transmembrane segments (S1, S2, S3, S5, S6) and one positively charged transmembrane segment (S4). S4 segments probably represent the voltage-sensor and are characterized by a series of positively charged amino acids at every third position.
Function
Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. The isoform alpha-1A gives rise to P and/or Q-type calcium currents. P/Q-type calcium channels belong to the 'high-voltage activated' (HVA) group and are specifically blocked by the spider omega-agatoxin-IVA (AC P30288) (PubMed:1311418). They are however insensitive to dihydropyridines (DHP).
Sequence Similarities
Belongs to the calcium channel alpha-1 subunit (TC 1.A.1.11) family. CACNA1A subfamily.
Tissue Specificity
Brain specific. Purkinje cells contain predominantly P-type VSCC, the Q-type being a prominent calcium current in cerebellar granule cells. Also found in heart, in kidney distal convoluted tubule (DCT), and in pituitary.
Cellular localization
- Cell membrane
- Multi-pass membrane protein
Alternative names
Cach4, Cacn3, Cacnl1a4, Cacna1a, Voltage-dependent P/Q-type calcium channel subunit alpha-1A, Brain calcium channel I, Rat brain class A, Voltage-gated calcium channel subunit alpha Cav2.1, BI, RBA-I