Voltage-dependent calcium channel, T-type, alpha-1I subunit (IPR030162)

Short name: CACNA1I

Overlapping homologous superfamilies


Family relationships


This entry represents the T-type voltage-dependent calcium channel alpha-1I subtype, also known as Cav3.3. Sperm-specific CatSper1 and CatSper2 proteins can associate with and modulate the function of this channel, which might be important in the regulation of sperm motility [PMID: 17317015]. It may also play a role in regulating GABAergic neurons [PMID: 21344408].

Voltage-dependent calcium channels (VDCCs) 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. T-type VDCC belongs to low-voltage-activated (LVA) Ca2+ channels, whereas others belong to high-voltage-activated (HVA) Ca2+ channels.

VDCCs consist of subunits. The alpha-1 subunit constitute the pore region which determines the fundamental channel properties [PMID: 7516685]. Three types of alpha-1 subunit have been identified in T-type VDCCs molecules: alpha-1G [PMID: 10692398], alpha-1H [PMID: 9670923], and alpha-1I [PMID: 10749850]. T-currents generated by the alpha-1I subunit display slow kinetics that differ markedly from the alpha-1G and alpha-1H currents [PMID: 10594642, PMID: 10749850, PMID: 11073957].

GO terms

Biological Process

GO:0070509 calcium ion import
GO:0030317 flagellated sperm motility
GO:0019228 neuronal action potential

Molecular Function

GO:0008332 low voltage-gated calcium channel activity

Cellular Component

GO:0005891 voltage-gated calcium channel complex

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.