Fig. 6.

Pathogenic mechanism of a secretion-competent ADLTE mutation, LGI1^R474Q. a–c Tandem-affinity purification (TAP) of LGI1^WT and LGI1^R474Q tagged with FLAG and His₆ from the indicated mouse brain extracts. Shown are the silver staining of TAP eluates (a) and Western blots of input (left) and TAP eluates (right) with indicated antibodies (b). Quantification of the amount of co-purified ADAM22 and ADAM23 with tagged LGI1 is shown in the graph (c). Known co-purified proteins were indicated (a). **P < 0.01; n.s. not significant; n = 3 independent experiments (c). Two-tailed Student’s t test was used. d, e Immunoprecipitation (IP) of ADAM23 from the indicated mouse brain extracts. Shown are Western blots of input (left) and IP (right) samples with indicated antibodies (d). Quantification of the amount of ADAM22 co-immunoprecipitated with ADAM23 is shown in the graph (e). f, g IP of ADAM22 from the indicated mouse brain extracts. **P < 0.01; *P < 0.05; n = 4 independent experiments. One-way ANOVA followed by post hoc Tukey’s test was used (e, g). Results are shown as mean ± s.e. h Model of tripartite complex comprising ADAM22–LGI1–ADAM23 at 1:2:1 stoichiometry. Two heterodimers, LGI1–ADAM22 and LGI1–ADAM23, are arranged in the LGI1-mediated head-to-head configuration to form the tetrameric complex (left). The R474Q mutation (asterisk) in LGI1 disrupts the LGI1–LGI1 interaction (right)