hnRNP A2 activates the Ras-MAPK-ERK pathway. (A,B) PHM-1 (A) and HuH7 (B) cells transduced with the indicated retroviruses were seeded in six-well plates (1 × 105 cells/well for PHM-1 cells, 2 × 105 cells/well for HuH7 cells). Cells were serum-starved for 24 h (0.1% FCS) and stimulated with EGF (10 nM) for 30 min. Cells were lysed and immunoblotted for expression of phosphorylated and total MEK1/2, ERK1/2 and T7-Tag (A) or hnRNP A2/B1 and hnRNP A1/A1b (B). β-Actin was used as a loading control. Fold increase of ERK1/2 or MEK1/2 was normalized (phosphorylated/total protein levels) to that of untreated empty vector, which was arbitrarily set at one. Shown here is one representative experiment out of three repeats (see also Supplemental Fig. S4).
