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. 2019 Sep 26;151(11):1300–1318. doi: 10.1085/jgp.201912390

Figure 3.

Figure 3.

Variable efficacy of open-channel block by peptides from Purkinje cell proteins expressing β4 peptide-like sequences. (A) Na currents recorded in CA3 neurons without added intracellular peptides (left), with 200 µM β4 peptide (middle), and with 200 µM mutant β4 peptide mimicking the sequence in peptide-deletion mice (right). 50 mM extracellular Na, 0 TTX. Scale bars apply to all traces. (B) Top, Sequences of peptides tested aligned to the β4 peptide sequence. Green, conserved residues; yellow, conserved charge; white, nonconserved residues. Bottom, peak relative resurgent current for each peptide. (C) Na currents recorded with 200 µM intracellular FGF14-1a, GPR158, FGFR3, and MCTP1 peptides. Scale bars apply to all four traces. (D) Mean normalized transient current traces at −30 mV with 200 µM (left) or 400 µM (right) β4 (blue) or FGF14-1a (red) peptide. Scale bars apply to both traces. Inset, decay τfast and τslow for double exponential fits of transient current decay with 400 µM peptide. Data in B and D are mean ± SEM. *, P < 0.05. (E) Sample relative resurgent-like current traces with 200 µM FGF14-1a, FGF13-1a, and FGF14_L7S peptides.