AP-1

Activator Protein 1 (AP-1) is not a single protein, but a collective term referring to dimeric transcription factors composed of Jun (c-Jun, JunB, JunD), Fos (c-Fos, FosB, Fra-1, Fra-2) ATF (activating transcription factor, ATF-2, ATF-3/LRF1, ATF-4, ATF-5, ATF-6B, ATF-7, BATF, BATF-2, BATF-3, JDP2) or MAF (c-MAF, MafA, MafB, MafF, MafG, MafK and Nrl) subunits that bind to a common DNA site, the AP-1-binding site. AP-1 is involved in a plethora of cellular and physiological functions. It is acknowledged as a master integrator of a myriad of extracellular signals allowing cells to adapt to changes in their environment. AP-1 has also been implicated in various severe diseases. These include transplant rejection, fibrosis, organ injury and a variety of inflammatory pathologies such as rheumatoid arthritis, asthma and psoriasis. In addition, cancer is undoubtedly the most documented pathology involving AP-1 where its activity is often dysregulated and contributes to cell transformation, tumor progression, aggressiveness and resistance to treatments.