the Raf–MEK–ERK pathway induces phosphorylation of ATF2 Thr71, whereas subsequent ATF2 Thr69 phosphorylation requires the Ral–RalGDS–Src–p38 pathway. Cooperation between ERK and p38 was found to be essential for ATF2 activation by these mitogens; the activity of p38 and JNK/SAPK in growth factor-stimulated fibroblasts is insufficient to phosphorylate ATF2 Thr71 or Thr69 + 71 significantly by themselves, while ERK cannot dual phosphorylate ATF2 Thr69 + 71 efficiently.
At the beginning of this reaction, 1 molecule of 'ATP', and 1 molecule of 'ATF-2' are present. At the end of this reaction, 1 molecule of 'ADP', and 1 molecule of 'ATF-2-P' are present.
This reaction is mediated by the 'protein kinase activity' of 'MAPK1-P'.