Calcium Channel, Voltage Dependent, T-Type, Alpha 1I Subunit (CACNa1I)

T-type channels, such as CACNA1I, are activated by small membrane depolarizations and can generate burst firing and pacemaker activity. The deduced 2,016-amino acid protein shows a membrane topology with 4 domains, each consisting of 6 membrane-spanning segments, a pore loop, and cytoplasmic and extracellular connecting loops. The N and C termini are cytoplasmic. The putative extracellular loops contain 5 potential N-glycosylation sites and 17 cysteines that may contribute to proper protein conformation. The long intracellular interdomain loops contain 28 potential phosphorylation sites. The membrane-spanning segments of CACNA1I are 84% identical to the membrane-spanning segments of CACNA1G and CACNA1H.