Xenbase Image ID: 128133

Figure 2. MTS-TBAO block and modification of TREK-1. (A) TREK-1 channel currents expressed in Xenopus oocytes measured at -80 mV in inside-out patches, activated from pH 8 by pH 5 and exposed to MTS-TBAO for 120 sec. A small and reversible block [8.2 ± 0.5% at 100 µM; (n = 4)] by the TBAO-moiety was obtained. (B) Concentration-response curves for tetrabutylammonium (TButA) inhibition of wild-type TREK-1 and G186C channels fitted to a standard Hill function with IC50 values and Hill-coefficients of 4.8 ± 0.3 mM and 1.4 ± 0.1 (n = 5) for wt; 0.5 ± 0.1 mM and 1.1 ± 0.1 for G186 (n = 6). Data points represent mean ± SEM (C) Structural model of the P1 subunits in the TREK-1 pore, the M3 and M4 helices from the P2 subunit are removed for clarity. The MTS-TBAO was linked to the introduced cysteines at position 186 with the SH-group in yellow, which is located in close proximity to the predicted QA binding site (green). (D) Application of MTS-TBAO on TREK-1-G186C mutant channels results in an initial fast block [24.2 ± 1% at 20 µM; (n = 5)] followed by a monoexponential time course [τ = 18.6 ± 3.9 sec; (n = 5)] for the modification of this cysteine that irreversibly reduced the current by up to 90%. Image published in: Rapedius M et al. (2012) Copyright © 2012 Landes Bioscience. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license Larger Image Printer Friendly View

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