Table 1.

Biophysical properties of Ca_V1.2 mutants

Ca_V1.2 WT or mutant was co-expressed with Ca_Vβ3 and either pmCherry–mock vector or pmCherry–Ca_Vα2δ1–HA WT or mutants using a 4:4:4 μg ratio. Biophysical parameters were measured in the presence of 2 mm Ca²⁺ as described elsewhere (25, 27). Activation properties (E_{0.5, act} and ΔG_act) were estimated from the mean I–V relationships and fitted to a Boltzmann equation. Null-current cells outnumbered the cells with inward currents for Ca_V1.2 D181R (12 null cells) and D181G (8 null cells). The data are shown as the mean ± S.E. of the number of cells (1 cell per experiment), and the total number of experiments carried over several months appears in parentheses. Statistical analysis was carried out against the values obtained in the presence of the mock pmCherry–N1 vector. NE means: no inward current;*, p < 0.01;**, p < 0.001.

CaV1.2 WT or mutants with CaVβ3 and mCherry–CaVα2δ1–HA	Electrophysiological properties in 2 mm Ca2+
	Peak current density	E0.5, act	ΔGact
	pA/pF	mV	kcal mol−1
mCherry mock vector	−2.5 ± 0.3 (25)	+8 ± 2	+0.5 ± 0.1
CaV1.2 WT	−18 ± 1 (243)**	−8.3 ± 0.2**	−0.78 ± 0.03**
CaV1.2-BTX (Ser-182)	−2 ± 1 (18)	+6 ± 1	+0.4 ± 0.1
CaV1.2-HA (Ser-182)	−5 ± 2 (10)	+7 ± 1	+0.5 ± 0.1
CaV1.2-HA (Glu-331)	−17 ± 4 (10)**	−8.8 ± 0.5**	−0.8 ± 0.1**
CaV1.2-HA (Asp-710)	−16 ± 2 (19)**	−8.8 ± 0.3**	−0.80 ± 0.04**
CaV1.2 E179G	−27 ± 2 (8)**	−11 ± 1**	−1 ± 0.1**
CaV1.2 E179A	−21 ± 3 (16)**	−5 ± 2**	−0.5 ± 0.1**
CaV1.2 E179I	−20 ± 3 (9)**	−7 ± 1**	−0.6 ± 0.1**
CaV1.2 E179R	−16 ± 3 (13)**	−6 ± 1**	−0.6 ± 0.1**
CaV1.2 D180G	−18 ± 2 (18)**	−2 ± 1*	−0.04 ± 0.08*
CaV1.2 D180I	−8 ± 1 (12)**	+3 ± 1	+0.24 ± 0.07
CaV1.2 D180A	−9 ± 1 (14)**	+3 ± 1	+0.2 ± 0.1
CaV1.2 D180E	−18 ± 3 (15)**	−3 ± 1*	−0.2 ± 0.1*
CaV1.2 D181G	−3 ± 2 (3)	+7 ± 4	+0.4 ± 0.3
CaV1.2 D181A	−4 ± 1 (8)**	+11 ± 6	+0.4 ± 0.2
CaV1.2 D181R	−1 ± 1 (2)	+6 ± 1	+ 0.4 ± 0.1
CaV1.2 D181E	−14 ± 3 (14)**	−4 ± 1*	−0.2 ± 0.1*
CaV1.2 D180E/D181E	−24 ± 8 (8)**	+5 ± 2	+0.3 ± 0.2
CaV1.2 S182G	−9 ± 2 (20)**	−7 ± 1**	−0.5 ± 0.1**
CaV1.2 S182A	−23 ± 7 (9)**	−8 ± 2**	−0.8 ± 0.2**
CaV1.2 S182R	−23 ± 7 (9)**	−7 ± 2**	−0.6 ± 0.1**
CaV1.2 N183G	−11 ± 2 (9)**	−7 ± 2**	−0.7 ± 0.1**
CaV1.2 N183A	−24 ± 6 (7)**	−11 ± 1**	−1 ± 0.1**
CaV1.2 N183R	−13 ± 3 (7)**	−6 ± 1**	−0.5 ± 0.1**
CaV1.2 N183Q	−7 ± 1 (7)**	−3 ± 2*	−0.3 ± 0.1*
CaV1.2 A184G	−28 ± 7 (9)**	−11 ± 1**	−1.2 ± 0.2**
CaV1.2 A184D	−22 ± 4 (9)**	−7 ± 2**	−0.8 ± 0.2**
CaV1.2 A184R	−12 ± 3 (17)**	−7 ± 1**	−0.6 ± 0.1**
CaV1.2 S957G	−26 ± 4 (6)**	−12 ± 1**	−1.3 ± 0.2**
CaV1.2 K1100A	−19 ± 4 (9)**	−9 ± 1**	−0.9 ± 0.1**
CaV1.2 K1100A + CaVα2δ1–HA E174A	−14 ± 4 (9)**	−7 ± 1**	−0.6 ± 0.1**
CaV1.2 I1104G	−21 ± 5 (10)**	−12 ± 2**	−1.1 ± 0.2**
CaV1.2 G1109A	−14 ± 4 (10)**	−7 ± 1**	−0.7 ± 0.2**
CaV1.2 H1113G	−26 ± 7 (8)**	−8 ± 2	−0.8 ± 0.2
CaV1.2 R1119A	−12 ± 2 (31)**	−10 ± 1**	−0.9 ± 0.1**
CaV1.2 R1119A + CaVα2δ1–HA D171A	−10 ± 2 (9)**	−8 ± 1**	−0.7 ± 0.1**