Impairing the actin flow–L1 linkage by myc-NES-ΔN-shootin1 inhibits L1-dependent axon outgrowth. Neurons overexpressing myc-NES-ΔN-shootin1 or myc-GST were cultured on L1-Fc– or polylysine-coated coverslips for 48 h and stained by anti-myc antibody (A). Some were cotransfected with shRNA against L1. (B) The lengths of axons or the longest neuritis. (C) The percentage reduction in axons by expressing myc-NES-ΔN-shootin1 (mean ± SEM; *, P < 0.05, ***, P < 0.01; n = 3 independent cultures, 1,370 neurons were examined). Bar, 50 μm.