The breast cancer associated gene 3 (BCA3)-Rac1 interaction promotes nuclear factor-κB (NF-κB) signaling in 293 cells. (A) Upper panel: the indicated BCA3 constructs were transfected into 293 cells and immunoprecipitation performed using an anti-Rac1 antibody. Anti-His tag antibody was used to develop the blots. Full length BCA3, fragments 1+2 and 2+3 co-immunoprecipitated with Rac1 but there was almost no interaction of Rac1 with fragment 3. As shown in lanes 5 and 6, fragments 1 and 2 could not be individually expressed. Lower panel: inputs of the BCA3 constructs. (B) The indicated BCA3 constructs were co-transfected into 293 cells along with the Rac1 and the NF-κB luciferase reporter construct, and luciferase assays performed in the absence of tumor necrosis factor-α (TNF-α). Full-length BCA3 plus Rac1 and fragment 1+2 plus Rac1 significantly enhanced NF-κB activity. Data were analyzed by one-way ANOVA with Bonferroni post-test corrections (**p<0.01; ***p<0.001; NS, p>0.05). NS, not significant.