Inhibition of IL-2–induced Akt function by inactivating Syk.
(A) IL-2–starved NK92 cells were treated with piceatannol or DMSO or infected with recombinant vaccinia virus encoding SykT or CD56 irrelevant control gene. Cells were then stimulated with IL-2 and analyzed for Syk protein kinase activation. The same membrane was probed with anti-Syk to check for equal loading. (B) NK92 cells were treated with 10, 25, or 50 μM piceatannol or DMSO were stimulated with IL-2 and analyzed for Akt phosphorylation with Ser473-specific antibody. The same membrane was stripped and reprobed with anti–pan-Akt to check for equal loading. (C) NK92 cells treated with piceatannol, LY294002, wortmannin, or DMSO were stimulated with IL-2 before Western blot analysis of Akt phosphorylation Akt kinase activation with histone H2B as the substrate. The same membrane was probed with anti–pan-Akt to check for equal loading. (D) NK92 cells infected with recombinant vaccinia virus encoding SykT, p85(DN), or CD56 irrelevant control gene were stimulated with IL-2 and analyzed for Akt phosphorylation and Akt kinase activation. The same membrane was stripped and reprobed with anti–pan-Akt. Results are representative of 1 of 4 independent experiments.
