Fig 1: RacGAP Bcr knockdown in striatal/accumbal neurons enhances Rac/PAK signaling. (A) Striatal/accumbal brain slices were prepared from three 8-week-old C57BL/6J mice. The panels show the immunoblots of SRGAP2, SRGAP3, RICH, Bcr, Abr, and ß-Actin. (B) MDCKII cells were transfected with plasmids expressing the GST-tagged RacGAP domain of SRGAP2, SRGAP3, RICH2, Abr, or Bcr and were then stimulated with rHGF (100 pM, 15 min) at 37 °C. Transfected cells showing membrane ruffling were counted under confocal microscope. About 100 transfected cells for each group were counted. The error bars represent the mean ± SEM of three independent experiments. One-way ANOVA followed by Dunnett’s test, ns not significant, **** p < 0.0001. (C) Primary striatal/accumbal neurons were infected with EmGFP-control miRNA mimic-expressing AAV or EmGFP-Bcr miRNA mimic-expressing AAV at DIV 6. Bcr expression level was quantified by immunoblotting over three independent experiments. Upper panels show representative immunoblots. Quantification of the immunoblotting assay is shown in the bottom panels. The error bars represent the mean ± SEM of three independent experiments. One-way ANOVA followed by Dunnett’s test, **** p < 0.0001. (D) Primary striatal/accumbal neurons were infected with EmGFP-control miRNA mimic-expressing AAV or EmGFP-Bcr miRNA mimic-expressing AAV at DIV 6. PAK autophosphorylation was quantified by immunoblotting over three independent experiments. Upper panels show representative immunoblots. Quantification of the immunoblotting assay is shown in the bottom panel. The error bars represent the mean ± SEM of three independent experiments. One-way ANOVA followed by Dunnett’s test, * p < 0.05, ** p < 0.01. (E) Primary striatal/accumbal neurons were infected with EGFP-expressing AAV or EGFP-Bcr-GAP-expressing AAV. PAK autophosphorylation was quantified by immunoblotting over three independent experiments. Upper panels show representative immunoblots. Quantification of the immunoblotting assay is shown in the bottom panels. Student’s t-test, **** p < 0.0001.