Activator protein 1 complex (AP-1)

The Activator protein 1 (AP-1) complex is a dimeric transcription factor primarily composed of members of the Jun (c-Jun, JunB, JunD) and Fos (c-Fos, FosB, Fra-1, Fra-2) protein families, characterized by their basic leucine zipper (bZIP) domains [Hess et al., 2004, Chemical Reviews]. It plays a pivotal role in converting extracellular signals, such as growth factors, cytokines, and environmental stressors, into specific gene expression patterns that govern cell proliferation, differentiation, and apoptosis [Shaulian & Karin, 2002, Nature Cell Biology]. AP-1 binds to the heptameric DNA sequence 5'-TGAG/CTCA-3', known as the TPA-responsive element (TRE), to initiate transcription [UniProt, 2024]. In clinical contexts, AP-1 is frequently overexpressed in various cancers, contributing to tumor progression, metastasis, and drug resistance, and it is a key driver of pro-inflammatory cytokine production in diseases like rheumatoid arthritis and psoriasis [Zenz et al., 2008, Nature Reviews Cancer]. Pharmacological targeting of AP-1 involves small molecules like T-5224, which inhibits its DNA-binding activity, and indirect modulation via glucocorticoids or retinoids that interfere with its transcriptional assembly [Aikawa et al., 2008, Arthritis & Rheumatism; NIH, 2023].

Other names

AP1Activator protein 1Jun-Fos complexTranscription factor AP-1

Inhibition of DNA binding at the TRE site, interference with dimerization of Jun and Fos subunits, and transrepression by nuclear receptors.