FIGURE 4.
The P149Q (FGF12B) and P154Q (FGF13U) affect interaction with certain NaV1.x C termini and modulation of the respective NaV1.x channel. A, surface of FGF13 (PDB: 3HBW). Highlighted in blue are the 8 amino acids that comprise the predicted NaV1.x binding site (9); in red is P154 (using FGF13U numbering, homologous to Pro149 in FGF12B). B, Coomassie-stained gel showing bacterial cell supernatant (S) or metal affinity purified material (P) for the indicated combinations of a His6-tagged NaV1.x with the indicated mutant FHF. The FHF position is indicated by an arrowhead. C, immunoblots with the indicated antibodies (IB) of whole cell lysates or after immunoprecipitation with the indicated antibodies (IP) showing that NaV1.1 co-immunoprecipitates with FGF13U, but not the mutant FGF13UP/Q. D, intermediate inactivation for the indicated NaV1.x/FHF pairs. Protocol and details are the same as in Fig. 1E and Fig. 3D. Note that data previously shown in Fig. 1E and Fig. 3D are displayed as a solid or dashed line, without symbols. Fit parameters, statistics, and N are in Table 1.