Expression of raf Oncogenes Activates the PEA1 Transcription Factor Motif

PEA1 (AP1) motif transcription enhancer activity was stimulated by v-raf and more efficiently by activated c-raf-1 or A-raf than by their normal counterparts, in agreement with a role for PEA1 in transformation by raf. Mutations in the ATP-binding site of v-raf prevented activation, suggesting that phosphorylation is somehow required.