Xenbase Image ID: 121431

Figure 3. . MTSET effects on ionic currents of Shaker WTT and F370C mutant channels. (A) Activation curves of WTT and F370C channels, before and after 10.8 mM·s exposure to MTSET. Plotted is the normalized tail current at −100 mV following depolarizations to the indicated voltages. Boltzmann fits yielded V1/2 = −51 ± 1 mV and z = 3.8 ± 0.4 for WTT, and V1/2 = −54 ± 1 mV and z = 6.4 ± 0.8 for F370C. After MTSET exposure, the WTT currents were essentially unchanged with V1/2 = −55 ± 0.8 mV and z = 3.6 ± 0.4. Tail currents in F370C channels were reduced from ∼1 nA to a residual <5 pA for all tested depolarizations. (B) F370C currents in an inside-out patch exposed to 0.5 mM MTSET (1 min old). Depolarizations were given to +80 mV from a −80 mV holding potential every 830 ms; currents from sweeps 1, 4, 7, and 19 are shown. (C) The elicited current is plotted as a function of cumulative MTSET exposure. There is no MTSET effect on WTT Shaker channels (circles). (D) Scaled activation time course of the F370C current sweeps shown in B. The rising phase slows down as the MTSET modification progresses. (E) The corresponding scaled tail currents. The deactivation time courses of the three sweeps are indistinguishable. In all experiments, the computed MTSET exposure was corrected for hydrolysis as described in materials and methods. Image published in: Yang Y et al. (2004) Copyright © 2004, The Rockefeller University Press. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View

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