MTSET modification of L280C, I307C, and L415C.

<p><b>A</b>. Effect of MTSET on wildtype or mutant ASIC1a expressed in <i>Xenopus</i> oocytes. MTSET (300 µM) was applied at pH 7.4 for 3 minutes and removed by washing with pH 7.4 solutions. pH 5.0-evoked currents after MTSET incubation (“+ MTSET”) were compared to control currents in the same oocyte measured before MTSET application (“Control”). <b>B</b>–<b>C</b>. Quantification of (<b>B</b>) tau of inactivation (<i>n</i> = 6-8) and (<b>C</b>) residual current (<i>n</i> = 6-7). <b>D</b>. Representative recordings of steady-state desensitization (SSD) before and after MTSET modification. Oocytes were maintained at a basal of pH 7.9 and then incubated with pH 6.7 for 2 minutes to induce SSD (shaded bars) prior to activation with pH 5.0 (white bars). <b>E</b>. Quantification of MTSET-dependent changes in SSD (<i>n</i> = 5-6). <b>F</b>. Representative traces of MTSET exposure on pH-dependent activation. MTSET was applied as above and the response to pH 5.0 (white bars) or pH 6.5 (gray bars) from basal pH 7.4 was measured. <b>G</b>. Quantification of pH 6.5-mediated activation before and after MTSET modification (<i>n</i> = 6-8). Data are mean ± SEM. “**” and “***” indicate <i>p</i>-values < 0.01 and 0.001, respectively. Significance was determined with paired Student’s t-tests.