(A) Western blot analysis of Akt1 and PINCH1 upon single or combined siRNA-mediated Akt1 and PINCH1 knockdown in DLD1 cells. Radiation survival of DLD1 PINCH1 knockdown cells was determined upon Akt1 siRNA knockdown (mean ± SD; n = 3; *P < 0.05, **P < 0.01, t test). (B) Total and phosphorylated amounts of exogenous RFP-Akt1 (WT, S473D/T308D, S473A, S473A/T308A or ΔPH) and associated signaling molecules were evaluated in DLD1 PINCH1 knockdown cultures by Western blotting. (C) Clonogenic radiation survival (0–6 Gy X-rays) was measured in DLD1 PINCH1 knockdown cultures transiently transfected with RFP-Akt1 plasmids expressing WT, S473D/T308D, S473A, S473A/T308A, or ΔPH (mean ± SD; n = 3; *P < 0.05, **P < 0.01, t test). Representative images demonstrate colony formation under tested experimental conditions.