The Aryl Hydrocarbon receptor (AhR) is ligand activated transcription factor that regulates wide spectrum of gene expression. The main mediator of AhR is 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) or polycyclic aromatic hydrocarbons which are widespread environmental pollutant causing a variety of severe health effects, e.g. immunosuppression, carcinogenesis and hepatotoxicity.
AhR is a member of basic helix-loop-helix-Per-Arnt-Sim (bHLH-PAS) superfamily of transcription factors. In the absence of ligand, the AhR can be found in the cytosol, bound to a dimer of the heat shock protein of 90 kDa (Hsp90) and the immunophilin-like protein, AIP (also known as XAP2 and ARA9). Upon ligand binding, the AHR translocates to the nucleus and binds with ARNT. The AHR/ARNT heterodimer binds to xenobiotic response elements and regulates a diverse set of genes.
Proteins on this pathway have targeted assays available via the [CPTAC Assay Portal](https://assays.cancer.gov/available_assays?wp_id=WP2586).