AHR Protein, Human (His)

The Aryl Hydrocarbon Receptor (AHR) is a ligand-activated transcription factor that enables cellular adaptation to environmental, dietary, microbial, and metabolic cues, playing critical roles in development, immunity, and cancer. Upon ligand binding, AHR translocates to the nucleus, heterodimerizes with ARNT, and induces gene expression by binding to xenobiotic response elements (XRE). It regulates diverse processes, including angiogenesis, hematopoiesis, drug/lipid metabolism, cell motility, and immune modulation. Xenobiotics (e.g., halogenated aromatic hydrocarbons) act as ligands, triggering phase I/II metabolizing enzyme gene expression (e.g., CYP1A1). Natural ligands from plants, microbiota, and endogenous metabolism (e.g., tryptophan derivatives) also potently activate AHR. Notably, AHR suppresses anti-tumor immunity—tryptophan catabolites (indoles, kynurenic acid) promote cancer cell motility and dampen adaptive immunity via AHR activation. Additionally, AHR inhibits the circadian gene PER1 by repressing CLOCK-BMAL1-mediated transcription. by similar: The AHR:ARNT heterodimer binds the core DNA sequence 5'-TGCGTG-3' within dioxin response elements (DRE) to activate target gene transcription.