Figure 2. Depletion of protein kinase C (PKC)δ prevented ethambutol (EMB)-induced vacuolar formation. Retinal pigment epithelium (RPE)50 (A) or ARPE19 (C) and (D) were transfected with none (MOCK), shRNA of lamin (control shRNA), or combinations of shRNA fragments of PKCα (90/92 in A), PKC βII (D/A2 in A and C), or PKCδ (F/H, G/H in A and E/G in C), for 36 h followed by treatment with 0.8 mM EMB for 24 h. Pictures were taken under a phase contrast microscope with 200× (A, C) and 400× (D) magnification. (B) and (E) are quantitations of cytoplasmic vacuolization for (A) and (D), respectively, performed as described in Methods. These results are representative of five reproducible experiments. The number of vacuoles/per field were compared between indicated treatment groups using one way ANOVA followed by Dunnett’s post hoc tests. The asterisks (* and **) indicate statistical significance (p<0.05 and p<0.005, respectively, n=5) between the indicated groups.