Module 4: Figure SRF and AP-1
Activation of serum response factor (SRF) and activating protein-1 (AP-1).
One of the earliest consequences of growth factor activity is to stimulate the transcription of the transcription factors c-Fos and c-Jun. The latter then forms a dimer through a leucine zipper and binds to the 12-O-tetradecanoylphorbol 13-acetate (also called phorbol 12-myristate 13-acetate) (TPA)-responsive element (TRE). The interaction with TRE is regulated both by phosphorylation and by the oxidation state of a highly conserved cysteine residue located in the DNA-binding domain. A redox factor 1 (Ref-1) controls the redox state of a cysteine residue in the DNA-binding domain.