Figure 4.

Double mutant M335A/E373Q of the Slack channel can be functionally expressed but displays a complete loss of sodium sensitivity. A, Sample single-channel current traces of M335A/E373Q mutant with different cytosolic Na⁺ concentrations. B–D, Total amplitude histogram of single-channel currents with 0−1000 mm [Na⁺]_i was fitted with a Gaussian function. E, Comparison of averaged p_o values of M335A/E373Q in different cytosolic Na⁺ concentrations (Table 3). F, Sample traces of M335A/E373A in 0 and 200 mm [Na⁺]_i, respectively. G, Total amplitude histogram of single-channel currents with 0–400 mm [Na⁺]_i were fitted with a Gaussian function, respectively. The open probabilities of the M335A/E373A in different cytosolic sodium concentrations (Table 3).