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. 2009 Oct 5;284(48):33265–33274. doi: 10.1074/jbc.M109.052910

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+.