TASK-3 activation after Cys-159 covalent modification is impaired by L122D and V136E. Currents records from FRT monolayers expressing TASK-3 M159C (A), M159C/V136E (B), and M159C/L122D (C) exposed to 5 mM NEM, a cysteine-selective alkylating agent. Details of currents records are as described in Fig. 3. (D) Peak steady-state normalized current following 5 mM NEM modification for M159C, M159C/V136E, and M159C/L122D. Data are fitted as in Fig. 3; n = at least 3 ± S.D. for each. ***P < 0.001, statistical significance relative to TASK-3 M159C as determined by a one-way ANOVA and a post hoc Bonferroni multiple comparison test.