TABLE 3.
Parameters from Boltzmann fits of steady-state inactivation gating for wild-type NaV1.5 and DIII-IV linker alanine mutants
The number of cells is shown in parentheses. All channel types except for Y1494A show a calcium-dependent shift in the voltage dependence of inactivation gating. The impact of calcium on the slope factor, k, was more modest and was significant for only F1473A, Y1494A, and Y1495A.
0 μm Ca2+ |
10 μm Ca2+ |
|||
---|---|---|---|---|
V0.5 | k | V0.5 | k | |
mV | mV | |||
Wild type NaV1.5 | −109.4 ± 0.7 (7) | 8.8 ± 0.2 | −97.1 ± 1.0 (9)a | 8.1 ± 0.3 |
F1473A | −94.6 ± 1.2 (8) | 8.1 ± 0.3 | −88.0 ± 1.4 (9)a | 6.3 ± 0.1a |
Y1494A | −101.5 ± 1.5 (9) | 7.6 ± 0.3 | −100.7 ± 1.4 (10) | 6.3 ± 0.1a |
Y1495A | −106.8 ± 1.4 (6) | 8.6 ± 0.1 | −97.3 ± 0.96 (6)a | 7.0 ± 0.2a |
F1520A | −108.3 ± 0.2 (5) | 8.3 ± 0.2 | −96.9 ± 1.1 (5)a | 8.3 ± 0.2 |
F1522A | −110.0 ± 0.6 (5) | 8.0 ± 0.4 | −98.1 ± 0.6 (5)a | 7.3 ± 0.06 |
a Student's t test p < 0.005 versus 0 μm Ca2+.