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Overexpressed Cavβ3 Inhibits N-Type (Cav2.2) Calcium Channel Currents Through A Hyperpolarizing Shift Of "Ultra-Slow" And "Closed-State" Inactivation, Takahiro Yasuda, Richard J. Lewis, David J. Adams
Overexpressed Cavβ3 Inhibits N-Type (Cav2.2) Calcium Channel Currents Through A Hyperpolarizing Shift Of "Ultra-Slow" And "Closed-State" Inactivation, Takahiro Yasuda, Richard J. Lewis, David J. Adams
Illawarra Health and Medical Research Institute
It has been shown that β auxiliary subunits increase current amplitude in voltage-dependent calcium channels. In this study, however, we found a novel inhibitory effect of β3 subunit on macroscopic Ba 2+ currents through recombinant N- and R-type calcium channels expressed in Xenopus oocytes. Overexpressed β3 (12.5 ng/cell cRNA) significantly suppressed N- and R-type, but not L-type, calcium channel currents at "physiological" holding potentials (HPs) of -60 and -80 mV. At a HP of -80 mV, coinjection of various concentrations (0-12.5 ng) of the β3 with Cav2.2α1 and α 2δ enhanced the maximum conductance of expressed channels at lower β3 …