Figure 6.

Fyn^CA modulated the biophysical properties of Nav1.7 in ND7/23 cells through mechanisms unrelated to phosphorylation of Y1470 and Y1471. (a) The left panels shows the representative WT or YYFF mutant currents recorded from ND7/23 cells cotransfected with Fyn^CA or Fyn^DN. Cells expressing WT channels generated relative larger sodium currents when compared with cells expressing mutant channels. The right panel is the histogram of the mean current densities. Fyn^CA increased current densities of both WT and YYFF mutant channels. Data are presented as means ± SE, *p < 0.05 versus corresponding Fyn^DN control by Mann–Whitney test. (b) The left panel shows the representative Western blot image of membrane expression of WT and YYFF mutant channels cotransfected with Fyn^CA or Fyn^DN in ND7/23 cells. The right panel is the histogram of mean surface expressions of WT and YYFF channels normalized by the membrane expression level of WT/Fyn^CA. Data are obtained from six experiments and presented as mean ± SE, *p < 0.05 WT/Fyn^CA versus WT/Fyn^DN or YYFF/Fyn^CA versus YYFF/Fyn^DN; #p < 0.05, YYFF/Fyn^CA versus WT/Fyn^CA, by one-way ANOVA test. (c) The activation and steady-state fast inactivation curves of WT and mutant channels cotransfected with Fyn^CA or Fyn^DN. Fyn^CA shifted both activation and fast inactivation curves of WT channels to the hyperpolarizing direction in ND7/23 cells, which was remained in mutant channels. Data are presented as means ± SE. (d) The steady-state slow inactivation of WT and YYFF mutant channels. Fyn^CA shifted the slow inactivation curve of both channels to the hyperpolarizing direction and reduced the percentage of channels that are resistant to slow inactivation (R_resist). Data are presented as means ± SE. WT: wild type; YYFF: Nav1.7rG-Y1470F/Y1471F; GFP: Green Fluorescent Protein; GAPDH: glyceraldehyde phosphate dehydrogenase.