Calcium channel β subunits differentially modulate recovery of the channel from inactivation

Abstract
We examined the effects of calcium channel β subunits upon the recovery from inactivation of α1 subunits expressed in Xenopus oocytes. Recovery of the current carried by the L‐type α1 subunit (cyCav1) from the jellyfish Cyanea capillata was accelerated by coexpression of any β subunit, but the degree of potentiation differed according to which β isoform was coexpressed. The Cyanea β subunit was most effective, followed by the mammalian b3, b4, and β2a subtypes. Recovery of the human Cav2.3 subunit was also modulated by β subunits, but was slowed instead. β3 was the most potent subunit tested, followed by β4, then β2a, which had virtually no effect. These results demonstrate that different β subunit isoforms can affect recovery of the channel to varying degrees, and provide an additional mechanism by which β subunits can differentially regulate α1 subunits.