Figure 7.
Reelin activates Cdc42-dependent cellular motility. A, Activity of Cdc42 in a motile neuron was visualized by using FRET (Raichu-Cdc42). YFP/CFP ratio images were calculated to represent FRET efficiency (normalized EA), which is not identical to but is correlated with the activities of Cdc42 (top). The YFP stacks were used to determine motility in parallel over time (bottom). B, To demonstrate the increase of Cdc42 activity, which is associated with neurite motility, four different time points are presented in A (blue lines, I-IV) and in B. The corresponding movie of the stack is presented in supplemental Movie S5, available at www.jneurosci.org as supplemental material. Experiments were performed at least five times and similar results were obtained. C, EAs in distal neurites were averaged from two time intervals of 5 min, 15 min after the addition of Mock or Reelin (means ± SEM; n ≥ 6; **p < 0.01 vs Mock). D, Effects of Wiskostatin and Secramine on Reelin-induced motility. The motility of WT neurons was determined before and after bath application of Reelin, Wiskostatin, Secramine, or in combination, as indicated (means ± SEM; n ≥ 6; **p < 0.01 vs controls; #p < 0.05 vs Reelin). Cont., Control.