Introduction of the poly-glycine substitution in the α₁2.2 subunit disrupts (PG6), while poly-alanine substitution (PA6) preserves Ca_vβ regulation.

<p>Panels A–D show data obtained with PG6, while panels E–H show data obtained with PA6. (A, E) Peak current-voltage relationships normalized to cell capacitance for the respective α₁ mutant expressed alone or with β2a or β3. (B, F) Activation represented by the normalized conductance (G/G_max). The residual current after either 25 ms (C) or 350 ms (G) of depolarization divided by the maximum inward current, and plotted against test potential. Representative traces normalized to the peak inward current are shown in the inset. (D, H) Comparison of the β2a and β3 effects on steady-state inactivation estimated using 15 s prepulses to varying potentials. Dotted lines represent steady-state inactivation measured for WT channels in the presence of β3 (α₁2.2+α₂δ1+β3).