FIGURE 1.

Schematical presentation of the structure of AP-1 proteins. Activator protein 1 (AP-1) proteins include the JUN, FOS, activating transcription factor (ATF), and musculoaponeurotic fibrosarcoma (MAF) protein families, which can form homodimers and heterodimers through their leucine-zipper domains. The AP-1 proteins exhibit several domains, including the bZIP domain (leucine zipper plus basic domain), transactivation domains, and docking sites for several kinases, such as JNK or ERK. These kinases modulate the activity of those transcription factors by phosphorylation of serine and threonine residues.