Mutation of Y490 TrkB Shc binding site differentially affects block of TrkB-induced current suppression of Kv1.3 current by adaptor proteins nShc and Grb10. (A-F) Same experimental paradigm, notation, and analysis protocol as Fig. 9 with the substitution of mutant TrkB kinase (TrkBShc-) in which the recognition site (Y490) for nShc binding was altered by point mutation to F. Note that TrkB-induced current suppression observed in (B) is still blocked by co-transfection of nShc in (C) but not with Grb10 (D). Note that Grb10 co-transfection (E) but not nShc co-transfection (F) with Kv1.3 alone induced an increased rate of inactivation. (G) Histogram plot of the peak current amplitude for various transfection conditions and recordings as in (A-F). Data are normalized as a ratio of final current over initial current (I20/I0) and are expressed as mean ± S.E.M.; sample size as indicated. * = statistically significant by paired t-test at α ≤ 0.05. Dashed line = ratio of 1.0 or no change post-neurotrophin stimulation.