Actin signaling modulates neuronal gene expression. A, R62D decreased, G15S increased, and S14C did not influence SRF luciferase activity in neurons. B, R62D antagonized constitutively active SRF (SRF-VP16)-induced luciferase activity. C–F, SRF-VP16 (E) partially rescued R62D-decreased neurite length in contrast to SRF-VP16ΔMADS (D) used as control (quantified in F). G–M, R62D expression, confined to the nucleus (R62DNLS), was recognized by its FLAG tag. R62DNLS-positive neurons (H, J, L, arrows) showed severe structural abnormalities including decreased neurite length and lack of growth-cone filopodia. In control neurons (K), growth cones were collapsed by ephrin-A5 (K, arrowheads). Contrastingly, ephrin-A5 failed to collapse a growth cone (L, arrowhead) of an R62DNLS-expressing neuron (L, arrow; quantified in M). N, R62DNLS decreased SRF luciferase activity and counteracted SRF-VP16 enhanced gene activity (see B). O, SRF-VP16 fully rescued R62DNLS-decreased neurite length. P, Cytoplasmic R62D and R62DNLS modulated expression of MAL, but not SRF. R62DNLS decreased expression of a 100 kDa MAL protein, but upregulated a MAL variant of ∼70 kDa. Cytoplasmic R62D increased abundance of the 70 kDa MAL protein, but not of 100 kDa MAL. Triplicate culture of three different mice for R62D and R62DNLS are shown. Scale bars (C–E, G–L), 5 μm.