Activation of PKR Inhibits Cell Migration Figure 4. Activation of PKR inhibits cofilin. A: MDA-MB231 cells were treated with PIC (0 or 10 ng/ml) for indicated times. There were two controls; cells received no treatment (con) or cells were treated with Lipofectamine 2000 (Lipo). Cell lysates were collected for immunoblotting analysis of the phosphorylation/expression of PKR, p38 MAPK, MK2, LIMK1 and cofilin. The expression of actin served as a loading control. B: The relative levels of pp38, pMK2, pLIMK and pcofilin were quantified as described under the Materials and Methods and normalized to the expression of p38 MAPK, MK2, LIMK1 and cofilin respectively. * denotes a significant difference from untreated controls. C: MDA-MB231 cells were exposed to PIC (0 or 10 ng/ml) for 6 hours, and then cells were seeded on fibronectin-coated culture wells, allowing attachment for 3 hours. The expression of cofilin and actin was detected by immunofluorescent staining as described under the Materials and Methods. Arrows indicate the lamellipodia. Scale bar = 10 mm. These experiments were replicated three times. doi:10.1371/journal.pone.0047721.g004 PLOS ONE | www.plosone.org 7 October 2012 | Volume 7 | Issue 10 | e47721