Figure 1.

INF2 maintains podocyte cortical actin by opposing Rho/mDia activity. (A) Podocytes (undifferentiated) were respectively transfected with universal negative control siRNA duplex (control), INF2-targeting siRNA (INF2 KD), INF2 KD+DN-RhoA, INF2 KD+DN-mDia1, or INF2 KD, followed by treatment with cell permeable C3 transferase (Cytoskeleton Inc.; Rho inhibitor I, 1.0 µg/ml for 2 hours). Cortactin, DN RhoA (DN mDia1), and actin filaments (F-actin) were co-illustrated by immunofluorescent stain (Cortactin in red, DN-RhoA/DN mDia1 in green, and F-actin in blue). (B) INF2 knockdown by siRNA was confirmed by Western blotting. (C) High transfection efficiency of siRNA as reflected by Cy3-labeled siRNA duplex. The transfection efficiency was calculated as the number of Cy3-positive cells/100 cells with positive stain of DAPI. Both the relative area of cortical actin mesh (D) and the relative length of cortactin-positive membrane (E) were calculated for 20 randomly selected cells in each group; data were expressed as mean ± standard deviation. The difference among groups was statistically analyzed using one-way ANOVA and least significant difference test. *P<0.05 versus cells with INF2 KD only.