Human Aryl Hydrocarbon Receptor (AhR) Protein

Background

AHR is a ligand-activated transcription factor involved in sensing and responding to environmental toxins, such as dioxins and polycyclic aromatic hydrocarbons (PAHs). Upon ligand binding, AHR translocates from the cytoplasm to the nucleus, where it forms a heterodimer with the Aryl Hydrocarbon Receptor Nuclear Translocator (ARNT) and binds to DNA at xenobiotic response elements (XREs), regulating the expression of detoxification enzymes like CYP1A1 and CYP1B1. AHR is expressed in a variety of tissues, including the liver, skin, and immune system, and plays roles in xenobiotic metabolism, immune regulation, cell differentiation, and circadian rhythm modulation. Dysregulation of AHR activity is implicated in immune dysfunction, autoimmune diseases, and cancer, where it influences tumor progression and metastasis. AHR’s dual role in both normal homeostasis and pathological conditions makes it a target of interest in toxicology, immunology, and cancer research.