Cloning, mutagenesis, and deletion of DISC1 and Kal-7 were conducted as described in the prior publication25 (link). Wild-type, constitutively-active (Rac1-CA, G12V), and dominant-negative form of Rac1 (Rac1-DN, T17N) were from Missouri University of Science and Technology (Rolla, MO). H1-RNA polymerase III promoter-driven shRNA against DISC1 (#1 with strong effect and #2 with weaker effect), which also carry EGFP under the downstream of CMV promoter, were previously described25 (link). Cultured cells were transfected with plasmids by the use of LipofectAMINE2000 (Invitrogen). In primary neuron culture, 2μg of pSuper-Venus RNAi were transfected into 1.5 × 105 cells. For 293 cells, 2 μg of pRK/DISC1-HA expression construct and 2 μg of pSuper-Venus RNAi construct were transfected (at 90 % confluence in 18 mm dish). In standard analyses, primary neurons were transfected after 23 DIV and maintained for 1–6 days after transfection.