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Fig. 8 | BMC Biology

Fig. 8

From: Genomic, functional and structural analyses elucidate evolutionary innovation within the sea anemone 8 toxin family

Fig. 8

SA8-induced inhibition of hKV1.2 and selectivity profile of SA8. A Representative whole-cell hKV1.2 current traces were recorded using the voltage protocol shown above the raw current traces. Depolarizing pulses were repeated every 15 s, selected traces are shown in the absence of blockers (black, control) and upon reaching equilibrium block in the presence of 100 nM SA8 (red) or 14 nM charybdotoxin (ChTx, green, positive control). B Low affinity, concentration-dependent block of hKV1.2 channels by SA8 was determined by fitting a straight line to the reciprocal of the remaining current fraction (1/RCF) plotted as a function of SA8 concentration. The remaining current fraction (RCF) was calculated as I/I0, where I0 is the peak current in the absence and I is the peak current at the equilibrium block in the presence of SA8 at concentrations of 0.01, 0.1, 1, and 10 µM (filled circles). Points on the linear concentration–response curve represent the mean of four independent measurements where the error bars represent the standard error of mean (SEM). The line was drawn using linear least squares fit and the reciprocal of the slope of the best fit yielded an IC50 of 40.8 ± 4.9 µM. C The effect of SA8 (100 nM, except for KV10.1 and NaV1.7 which were tested at 1 µM) on the peak currents was reported as the RCF. Bars represent the mean of 3–6 independent measurements; error bars indicate the SEM. Data are shown for the following channels: HkV1.1 (n = 4), hKV1.2 (n = 4), hKV1.3 (n = 3), hKV10.1 (n = 4), hKV11.1 (n = 5), mKCa1.1 (n = 4), hKCa3.1 (n = 6), hTRPA1 (n = 5), hTRPV1 (n = 5), and hNaV1.7 (n = 5) (for details of the expression systems, solutions, and voltage protocols, see Materials and Methods, and for raw current traces see Additional File 13: Figure S9). SA8 did not inhibit any of the investigated channels at the applied concentrations. Supporting data values are available in Additional File 3: File S1

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