Figure 1.

Kinetics of Nav1.5 channel activation were not affected by FGF13 isoforms. (A) Diagram for FGF13 isoforms. Alternative splicing FGF13 isoforms are schematically shown with different color. (B) Representative families of currents recorded from tsA201 cells transiently co-transfected with Nav1.5 and either pIRES-GFP (Control) or one of the FGF13 isoforms (FGF13S, FGF13U and FGF13VY) subcloned into pIRES-GFP vector. (C) Summarized relative peak currents density for control or the FGF13 isoforms (**P < 0.01, compared to control). Numbers of cells tested are shown on the top of each column. (D) Steady-state conductance-voltage relationships of Nav1.5 channels in the absence and presence of FGF13 isoforms. Conductance was normalized to single Boltzmann fits, whose averages are represented by solid curves. (E) Normalized peak current-voltage relationships of Nav1.5 elicited from a holding potential of −120 mV to the indicated test voltages.