Figure 2. Ca_V1.1 structures involved in curtailing calcium currents.

A, top view of the Ca_V1.1 channel with the four homologous repeats shown in different colours, using the high‐resolution cryo‐EM structure of Wu et al. (2015). B and C, side views of VSD IV models constructed of the high‐resolution cryo‐EM structure (B), and our Rosetta structure models (C), of the two splice variants with and without exon 29 (grey) (Tuluc et al. 2015). Note the overall similarity of the predicted and experimentally obtained structures. Inclusion of exon 29 slightly displaces IVS3 and IVS4 relative to each other, resulting in a channel which fails to activate during physiological depolarizations. D and F, side view structure of the channel pore. E and G, critical pore residues of the calcium selectivity filter of the rabbit channel (rb‐α_1S) and the single amino acid substitutions which render the two fish Ca_V1.1 paralogues (zf‐α_1S‐a, ‐b, medaka‐α_1S‐b) non‐conductive (Schredelseker et al. 2010).