Alternative splicing within the I-II loop controls surface expression of T-type Ca(v)3.1 calcium channels

Molecular diversity of T-type/Cav3 Ca2+ channels is created by expression of three genes and alternative splicing of those genes. Prompted by the important role of the I-II linker in gating and surface expression of Cav3 channels, we describe here the properties of a novel variant that partially deletes this loop. The variant is abundantly expressed in rat brain, even exceeding transcripts with the complete exon 8. Electrophysiological analysis of the Δ8b variant revealed enhanced current density compared to Cav3.1a, but similar gating. Luminometry experiments revealed an increase in the expression of Δ8b channels at the plasma membrane. We conclude that alternative splicing of Cav3 channels regulates surface expression and may underlie disease states in which T-channel current density is increased.