Intra- and intermolecular distances between the Ca_v1.2 calcium channel α_1C and β subunits measured by three-color FRET microscopy.

P<0.002 vs. β₃.

P<0.05 vs. β_2d.

P<0.05 vs. β₃.

P<0.05 vs. r_V-R in Vα_1C+α_1CC+Rβ_2d.

FRET efficiency between the indicated fluorophores fused to the α_1C and β_1b, β_2d or β₃ subunits was measured in the plasma membrane of expressing COS1 cells and fitted to a Gaussian function. In cases when the routine curve fit showed two significantly different Gaussian distributions, the corresponding dispersion coefficients c (mean±SEM) are shown for both distances (see Experimental Procedures). V – mVenus, C- mCerulean, R – tagRFP. Shown values of r are mean±SEM. Number of cells is shown in parentheses.