A, OLA1-knockdown HeLa cells (stably transfected by shRNA, upper panel) and MDA-MB-231 cells (transiently transfected by siRNA, lower panel) were analyzed by immunoblotting for their expression of FAK and its phosphorylation. The effectiveness of OLA1-knockdown was evidenced by anti-OLA1 antibody probing and equivalent protein loading was verified with anti-β-actin antibody. B, Immunoblot analysis of OLA1-knockdown HeLa cells for detecting cytoskeletal signaling proteins including Crb2, Rac/cdc42, VASP, N-WASP, and their phosphorylation modification (pRac/cdc42, Ser71; pVASP, Ser157), with the corresponding antibodies. C, Additional immunoblot analysis with anti-cofilin and anti-phospho-cofilin (Ser3) antibodies. β-actin was used as a loading control. Note that in these experiments (A–C) duplicate samples prepared from independently transfected cells were loaded and analyzed on the same blot (to emphasize technical consistency). D, Densitomeric analysis of immunoblots shows fold changes of the FAK and pCofilin levels in OLA1 deficient cells compared to control cells. Data represent mean ± SD values from 3 independent experiments. **, p < 0.001.