Figure 2. Panel A shows families of... | Rockefeller University Press

Figure 2.

$All FGF-A homologues produce a similar rightward/depolarizing shift in SSI. (A) Families of currents resulting from the indicated SSI protocol (top) for NaV1.2 alone (top traces) or when coexpressed with FGF14A (red), FGF13A (blue), FGF12A (magenta), or FGF11A (green). Inactivation was elicited by a 500 ms conditioning pulse (left traces) to potentials over the range of −120 to 0 mV in 5 mV increments prior to a test pulse at 0 mV (right traces). (B) Effect of FGF14A on voltage dependence of SSI of NaV1.2 channels. Individual fractional availability was determined from INa evoked at 0 mV (test pulse) following a given conditioning potential with normalization to the maximum INa. Solid lines show Boltzmann fits to averaged data points (mean ± SD). (C) SSI curves and fits for NaV1.2+FGF13A. (D) NaV1.2+FGF12A. (E) NaV1.2+FGF11A. (F and G) Mean, SD, and individual estimates of Vh (F) and z (G) estimated from SSI curves (B−E) for NaV1.2 without and with the different FGF-A homologues. Numbers along bottom are the number of cells in each case. Fit parameters, N, and P values are summarized in Table S3. **P < 0.01, ***P < 0.001, and ****P < 0.0001. Refer to the image caption for details.$ Panel A shows families of sodium current traces with an inset steady state inactivation protocol on top, including conditioning pulses and test pulses, comparing NaV1.2 alone and with FGF14A, FGF13A, FGF12A, and FGF11A, with current and time scale bars. Panel B shows steady state inactivation curves of fractional availability versus command potential with data points, error bars, and fitted curves comparing wild type and FGF14A. Panel C shows steady state inactivation curves with data points, error bars, and fitted curves comparing wild type and FGF13A. Panel D shows steady state inactivation curves with data points, error bars, and fitted curves comparing wild type and FGF12A. Panel E shows steady state inactivation curves with data points, error bars, and fitted curves comparing wild type and FGF11A. Panel F shows scatter plot of half inactivation voltage values with individual data points, mean with error bars, and sample sizes indicated. Panel G shows scatter plot of slope factor values with individual data points, mean with error bars, and statistical significance indicated.

All FGF-A homologues produce a similar rightward/depolarizing shift in SSI. (A) Families of currents resulting from the indicated SSI protocol (top) for Na_V1.2 alone (top traces) or when coexpressed with FGF14A (red), FGF13A (blue), FGF12A (magenta), or FGF11A (green). Inactivation was elicited by a 500 ms conditioning pulse (left traces) to potentials over the range of −120 to 0 mV in 5 mV increments prior to a test pulse at 0 mV (right traces). (B) Effect of FGF14A on voltage dependence of SSI of Na_V1.2 channels. Individual fractional availability was determined from I_Na evoked at 0 mV (test pulse) following a given conditioning potential with normalization to the maximum I_Na. Solid lines show Boltzmann fits to averaged data points (mean ± SD). (C) SSI curves and fits for Na_V1.2+FGF13A. (D) Na_V1.2+FGF12A. (E) Na_V1.2+FGF11A. (F and G) Mean, SD, and individual estimates of V_h (F) and z (G) estimated from SSI curves (B−E) for Na_V1.2 without and with the different FGF-A homologues. Numbers along bottom are the number of cells in each case. Fit parameters, N, and P values are summarized in Table S3. **P < 0.01, ***P < 0.001, and ****P < 0.0001.