Figure 4. N-terminal domains of SNAP-25 sensitize Kv2.1 channels to TEA inhibition.

HEK-293 cells transiently transfected with Kv2.1 were perfused externally with TEA from 0.01 to 30 mM in the presence of internally dialysed GST (1 pM, n=6), S180 (1 pM, n=5), S197 or S206 (1 pM, n=5). Currents evoked are as described in Figure 1 and were measured at +50 mV. The current in the presence of TEA was normalized to pre-drug values, and expressed as the fraction of the current that was blocked. Data were fit with the Hill equation I/I_o=1/{1+(IC₅₀^h/[TEA]^h)}, where I/I_o is the fraction of current blocked, IC₅₀ is the concentration at which 50% of the current is blocked by TEA, and h is the Hill coefficient.