This study reports a novel splice variant form of the voltage-dependent calcium channel β2 subunit (β2g): This variant is composed of the conserved amino-terminal sequences of the β2a subunit, but lacks the β-subunit interaction domain (BID), which is thought essential for interactions with the α1 subunit. Gene structure analysis revealed that this gene was composed of 13 translated exons spread over 107 kb of the genome. The gene structure of the β2 subunit was similar in exon-intron organization to the murine β3 and human β4 subunits. Electrophysiological evaluation revealed that β2a and β2g, affected channel properties in different ways. The β2a subunit increased the peak amplitude, but failed to increase channel inactivation, while β2g had no significant effects on either the peak current amplitude or channel inactivation. Other β subunits, such as β3 and β4, significantly increased the peak current and accelerated current inactivation.
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