1. Requirement for a β subunit for the modulation of whole-cell CaV2
Requirement for a β subunit for the modulation of whole-cell CaV2.2 currents by Gβγ in COS-7 cells.
Requirement for a β subunit for the modulation of whole-cell CaV2.2 currents by Gβγ in COS-7 cells. A, slowed activation of CaV2.2/β2a currents by Gβ1γ2 coexpression. Left top panel, voltage protocol, holding potential -80 mV, P1 and P2 test pulses to between -40 and +60 mV, with intervening prepulse to +100 mV; lower panel, example current traces for P1 and P2 to 0 mV for CaV2.2/β2a/Gβ1γ2. Right, plot of time constant for activation (τact) against voltage for P1 currents in the presence of Gβγ (•), compared with coexpression of β-ARK1 minigene (○). B, lack of slowed activation of CaV2.2 currents by Gβγ in the absence of CaVβ subunits. Left, example current traces for P1 and P2 to 0 mV for CaV2.2/Gβ1γ2. Right, plot and symbols as above. Note that traces in A are recorded in 1 mM Ba2+ and those in B are recorded in 10 mM Ba2+. Scale bars represent 10 pA/pF and 50 ms for both. Data replotted from Meir et al. (2000).
Annette C. Dolphin Pharmacol Rev 2003;55:
The American Society for Pharmacology and Experimental Therapeutics