FIGURE 4:

The effect of RhoA inhibitor C3 transferase on filopodial assembly and SV clustering. (A–C) Control neurons expressing GFP had filopodia and SV clusters along axons, and after treatment with C3 toxin (A′–C′) they showed an increase in axonal filopodia and SV clustering. (D–F) WTp120 expression enhanced both filopodial assembly and SV clustering, and addition of C3 toxin to these neurons (D′–F′) did not further elevate the effect. (G–I) Δp120 expression suppressed the formation of filopodia and SV clusters, and, significantly, this inhibitory effect of Δp120 was reversed in the presence of C3 toxin (G′–I′). These changes in the densities of filopodia and SV clusters are quantified in J and K. Mean and SEM are shown. *p < 0.05, ***p < 0.001, compared with control; ^p < 0.05, ^^p < 0.01, ^^^p < 0.001, compared with no treatment.