Figure 4.
siRNA-Fyn inhibits phosphorylation of STAT1 (Ser727), ATF-2 (Thr71), and p38MAPK (Thr180/Tyr182). Cells were treated as described in Methods and Materials and phosphorylation of selected proteins was determined by Western blot. (A) Phosphorylation of ERKs (Ser42/Ser 44) was detected with a specific phospho-ERKs (Ser42/44) antibody and total ERKs protein levels were detected by a non-phospho-ERKs antibody (A, left). Fyn expression was confirmed in SiRNA-Fyn JB6 cells and mock cells by Western blot (A, right). (B) Phosphorylation of STAT1 (Ser727), ATF-2 (Thr71), and p38 MAPK (Thr180/Tyr182) were separately detected with specific phospho-STAT1, ATF-2, and p38MAP kinase antibodies. Total protein levels of STAT1, ATF-2, and p38 MAP kinase were detected by a non-phospho-STAT1, ATF-2, or p38 MAP kinase antibody, respectively. (C) SiRNA-Fyn JB6 cells and mock cells were treated with EGCG as described in Methods and Materials. Phosphorylation of STAT1 (Ser727), ATF-2 (Thr71), and p38 MAPK (Thr180/Tyr182) was also detected by Western blot. Respective total protein levels served as controls.